[go: up one dir, main page]
More Web Proxy on the site http://driver.im/

WO2014016206A1 - Film with low ocs gel index - Google Patents

Film with low ocs gel index Download PDF

Info

Publication number
WO2014016206A1
WO2014016206A1 PCT/EP2013/065263 EP2013065263W WO2014016206A1 WO 2014016206 A1 WO2014016206 A1 WO 2014016206A1 EP 2013065263 W EP2013065263 W EP 2013065263W WO 2014016206 A1 WO2014016206 A1 WO 2014016206A1
Authority
WO
WIPO (PCT)
Prior art keywords
polypropylene
melt
melt strength
range
branched
Prior art date
Application number
PCT/EP2013/065263
Other languages
French (fr)
Inventor
Katja Klimke
Hermann Braun
Original Assignee
Borealis Ag
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Borealis Ag filed Critical Borealis Ag
Priority to CA2878305A priority Critical patent/CA2878305C/en
Priority to JP2015523504A priority patent/JP5986314B2/en
Priority to BR112015000853A priority patent/BR112015000853A2/en
Priority to ES13739223.9T priority patent/ES2626363T3/en
Priority to US14/414,825 priority patent/US9376549B2/en
Priority to IN10848DEN2014 priority patent/IN2014DN10848A/en
Priority to EP13739223.9A priority patent/EP2877535B1/en
Priority to KR1020157003771A priority patent/KR101531814B1/en
Priority to MX2015000615A priority patent/MX366376B/en
Priority to CN201380037223.9A priority patent/CN104718249B/en
Publication of WO2014016206A1 publication Critical patent/WO2014016206A1/en

Links

Classifications

    • CCHEMISTRY; METALLURGY
    • C08ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08LCOMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L51/00Compositions of graft polymers in which the grafted component is obtained by reactions only involving carbon-to-carbon unsaturated bonds; Compositions of derivatives of such polymers
    • C08L51/06Compositions of graft polymers in which the grafted component is obtained by reactions only involving carbon-to-carbon unsaturated bonds; Compositions of derivatives of such polymers grafted on to homopolymers or copolymers of aliphatic hydrocarbons containing only one carbon-to-carbon double bond
    • CCHEMISTRY; METALLURGY
    • C08ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08KUse of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K5/00Use of organic ingredients
    • C08K5/49Phosphorus-containing compounds
    • C08K5/51Phosphorus bound to oxygen
    • C08K5/52Phosphorus bound to oxygen only
    • CCHEMISTRY; METALLURGY
    • C08ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08FMACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F10/00Homopolymers and copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond
    • C08F10/04Monomers containing three or four carbon atoms
    • C08F10/06Propene
    • CCHEMISTRY; METALLURGY
    • C08ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08FMACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F2/00Processes of polymerisation
    • C08F2/46Polymerisation initiated by wave energy or particle radiation
    • C08F2/48Polymerisation initiated by wave energy or particle radiation by ultraviolet or visible light
    • CCHEMISTRY; METALLURGY
    • C08ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08FMACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F2/00Processes of polymerisation
    • C08F2/46Polymerisation initiated by wave energy or particle radiation
    • C08F2/52Polymerisation initiated by wave energy or particle radiation by electric discharge, e.g. voltolisation
    • CCHEMISTRY; METALLURGY
    • C08ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08FMACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F2/00Processes of polymerisation
    • C08F2/46Polymerisation initiated by wave energy or particle radiation
    • C08F2/54Polymerisation initiated by wave energy or particle radiation by X-rays or electrons
    • CCHEMISTRY; METALLURGY
    • C08ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08FMACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F210/00Copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond
    • C08F210/04Monomers containing three or four carbon atoms
    • C08F210/06Propene
    • CCHEMISTRY; METALLURGY
    • C08ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08FMACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F210/00Copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond
    • C08F210/16Copolymers of ethene with alpha-alkenes, e.g. EP rubbers
    • CCHEMISTRY; METALLURGY
    • C08ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08FMACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F255/00Macromolecular compounds obtained by polymerising monomers on to polymers of hydrocarbons as defined in group C08F10/00
    • C08F255/02Macromolecular compounds obtained by polymerising monomers on to polymers of hydrocarbons as defined in group C08F10/00 on to polymers of olefins having two or three carbon atoms
    • CCHEMISTRY; METALLURGY
    • C08ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08JWORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J5/00Manufacture of articles or shaped materials containing macromolecular substances
    • C08J5/18Manufacture of films or sheets
    • CCHEMISTRY; METALLURGY
    • C08ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08KUse of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K3/00Use of inorganic substances as compounding ingredients
    • C08K3/18Oxygen-containing compounds, e.g. metal carbonyls
    • C08K3/24Acids; Salts thereof
    • C08K3/26Carbonates; Bicarbonates
    • CCHEMISTRY; METALLURGY
    • C08ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08KUse of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K5/00Use of organic ingredients
    • C08K5/04Oxygen-containing compounds
    • C08K5/10Esters; Ether-esters
    • C08K5/11Esters; Ether-esters of acyclic polycarboxylic acids
    • CCHEMISTRY; METALLURGY
    • C08ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08LCOMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L23/00Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers
    • C08L23/02Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers not modified by chemical after-treatment
    • C08L23/10Homopolymers or copolymers of propene
    • C08L23/12Polypropene
    • CCHEMISTRY; METALLURGY
    • C08ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08LCOMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L23/00Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers
    • C08L23/02Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers not modified by chemical after-treatment
    • C08L23/10Homopolymers or copolymers of propene
    • C08L23/14Copolymers of propene
    • C08L23/142Copolymers of propene at least partially crystalline copolymers of propene with other olefins
    • CCHEMISTRY; METALLURGY
    • C08ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08JWORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J2351/00Characterised by the use of graft polymers in which the grafted component is obtained by reactions only involving carbon-to-carbon unsaturated bonds; Derivatives of such polymers
    • C08J2351/06Characterised by the use of graft polymers in which the grafted component is obtained by reactions only involving carbon-to-carbon unsaturated bonds; Derivatives of such polymers grafted on to homopolymers or copolymers of aliphatic hydrocarbons containing only one carbon-to-carbon double bond
    • CCHEMISTRY; METALLURGY
    • C08ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08LCOMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L23/00Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers
    • C08L23/26Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers modified by chemical after-treatment
    • C08L2023/40Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers modified by chemical after-treatment by reaction with compounds changing molecular weight
    • C08L2023/42Depolymerisation, vis-breaking or degradation
    • CCHEMISTRY; METALLURGY
    • C08ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08LCOMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L2203/00Applications
    • C08L2203/16Applications used for films
    • CCHEMISTRY; METALLURGY
    • C08ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08LCOMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L2205/00Polymer mixtures characterised by other features
    • C08L2205/02Polymer mixtures characterised by other features containing two or more polymers of the same C08L -group
    • C08L2205/025Polymer mixtures characterised by other features containing two or more polymers of the same C08L -group containing two or more polymers of the same hierarchy C08L, and differing only in parameters such as density, comonomer content, molecular weight, structure
    • CCHEMISTRY; METALLURGY
    • C08ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08LCOMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L2207/00Properties characterising the ingredient of the composition
    • C08L2207/06Properties of polyethylene
    • C08L2207/07Long chain branching

Definitions

  • the present invention relates to a method of providing a polypropylene composition having high melt strength and a low OCS gel index. Furthermore, the present invention also relates to a corresponding high melt strength (HMS) polypropylene composition with low OCS gel index.
  • HMS high melt strength
  • High melt strength polypropylene (HMS-PP) compositions are generally known in the art.
  • HMS-PP High melt strength polypropylene
  • one challenge within existing HMS-PP is their varying film quality.
  • the film quality is expressed via the gel index which is measured with the OCS gel inspection tool as described in WO 2008/022802.
  • additives are normally added to plastic materials in order to improve the performance thereof.
  • typical additives are e.g. antioxidants or pigments etc.
  • These additives are often added to the plastic base material in the form of an additive mixture having incorporated the additives into a small amount of polymer powder.
  • the additive mixture is sometimes also referred to as masterbatch.
  • the small quantity of polymer powder used for the additive mixture is normally dosed at the end of the HMS process.
  • the contribution to the final gel index of this additive mixture is often overlooked. Further up to now it has been not recognized that also the molecular weight of the base polymer powder in the manufacture of the high melt strength polypropylene (HMS- PP) has significant impact on the final optical properties.
  • EP 0 879 830 filed by Borealis in 1997, describes the basics of the Borealis high melt strength (HMS) post-reactor process where peroxide and butadiene are used to make long chain branched polypropylene (LCB-PP) materials.
  • HMS high melt strength
  • LCB-PP long chain branched polypropylene
  • MFRs powder melt flow rates
  • the object of the present invention is to provide a process which enables a skilled person to produce a polypropylene composition and a film made of said
  • the present invention relates to a process for providing a polypropylene composition comprising a branched polypropylene (b-PP), like comprising at least 90 wt.-% of a branched polypropylene (b-PP), the process comprises at least a step (a) in which a polypropylene (PP) is reacted with a thermally decomposing free radical- forming agent and optionally with bifunctionally unsaturated monomer(s) and/or with multifunctionally unsaturated low molecular weight polymer(s) obtaining thereby the branched polypropylene (b-PP),
  • the polypropylene (PP) has a melt flow rate MFR 2 (230°C) of more than 1.0
  • g/lOmin preferably in the range of more than 1.0 to 13.0 g/lOmin, like 3.0 to 13 g/lOmin;
  • the polypropylene composition and/or the branched polypropylene (b-PP) has/have a F 30 melt strength of more than 5.8 cN and a V30 melt extensibility of more than 200 mm/s, wherein the F 30 melt strength and the V30 melt extensibility are measured according to ISO 16790:2005.
  • the present invention further provides a polypropylene composition comprising
  • polypropylene composition has a melt flow rate MFR 2 (230 °C) measured according to ISO 1133 of 7.0 to
  • the individual components i.e. the polypropylene (PP), like the linear polypropylene (1- PP'), the polypropylene ( ⁇ '), like the linear polypropylene ( ⁇ - ⁇ '), the branched polypropylene (b-PP), and the additives (A), used in the instant invention as well as the polypropylene composition are described. Subsequently the claimed process is described in more detail. However any information or any preferred embodiment provided for the individual components or the polypropylene composition is also applicable for the inventive process, if reference is made to the individual components and the polypropylene composition, respectively.
  • PP polypropylene
  • ⁇ ' like the linear polypropylene
  • b-PP branched polypropylene
  • A additives
  • the branched polypropylene (b-PP) The major component for the polypropylene composition to be provided according to the invention is a branched polypropylene (b-PP).
  • a branched polypropylene differs from a linear polypropylene that the polypropylene backbone covers side chains whereas a non- branched polypropylene, i.e. a linear polypropylene, does not cover side chains.
  • the side chains have significant impact on the rheology of the polypropylene. Accordingly linear polypropylenes and branched polypropylenes can be clearly distinguished by its flow behavior under stress. Branching can be achieved by using specific catalysts, i.e. specific single-site catalysts, or by chemical modification.
  • branched polypropylene obtained by the use of a specific catalyst reference is made to EP 1 892 264.
  • a branched polypropylene obtained by chemical modification it is referred to EP 0 879 830 Al .
  • the branched polypropylene is also called high melt strength polypropylene.
  • the branched polypropylene (b-PP) according to the instant invention is obtained by chemical modification as described in more detail below and thus is a high melt strength
  • HMS-PP polypropylene
  • the branched polypropylene (b-PP), i.e. the high melt strength polypropylene (HMS-PP), as the major component of the polypropylene composition has a F 30 melt strength of more than 5.8 cN and a V30 melt extensibility of more than 200 mm/s, preferably has a F 30 melt strength of more than 5.8 to 20.0 cN and a V30 melt extensibility of more than 200 to 300 mm/s, in order to provide a resulting polypropylene composition with good shear thinning properties.
  • the F 30 melt strength and the V30 melt extensibility are measured according to ISO 16790:2005.
  • the instant polypropylene composition also has a F 30 melt strength of more than 5.8 cN and a V30 melt extensibility of more than 200 mm/s, preferably has a F 30 melt strength of more than 5.8 to 20.0 cN and a V30 melt extensibility of more than 200 to 300 mm/s.
  • the branched polypropylene (b-PP), i.e. the high melt strength polypropylene (HMS-PP), has
  • the branched polypropylene (b-PP), i.e. the high melt strength polypropylene (HMS-PP), has a F 30 melt strength of more than 5.8 cN and a V30 melt extensibility of more than 210 to 300 mm/s, like a F 30 melt strength of more than 5.8 to 20.0 cN and V30 melt extensibility of more than 220 to 300 mm/s, more preferably a F 30 melt strength of more than 6.0 cN and V30 melt extensibility of more than 225 mm/s, still more preferably a F 30 melt strength of 6.0 to 18.0 cN and V30 melt extensibility of 225 to 300 mm/s, yet more preferably a F 30 melt strength of 6.2 to 15.0 cN and V30 melt extensibility of 230 to 290 mm/s, still yet more preferably a F 30 melt strength of 6.2 to 13.0 cN and V30 melt extensibility of 230 to 290 mm/s, most
  • the branched polypropylene (b-PP), i.e. the high melt strength polypropylene (HMS-PP), can be further defined by the strain hardening factor (SHF). Accordingly it is preferred that the branched polypropylene (b-PP), i.e. the high melt strength polypropylene (HMS-PP), has a strain hardening factor (SHF) of at least 1.7, more preferably of at least 1.9, yet more preferably in the range of 1.9 to 7.0, still more preferably in the range of 1.9 to 6.5 measured at a strain rate of 3.0 s "1 and a Hencky strain of 2.5.
  • SHF strain hardening factor
  • said branched polypropylene (b-PP), preferably the high melt strength polypropylene (HMS-PP), has a melt flow rate MFR 2 (230 °C) measured according to ISO 1133 of at least 2.0 g/lOmin, more preferably in a range of 2.0 to 40.0 g/10 min, still more preferably in a range of 4.0 to 30.0 g/10 min, yet more preferably in a range of 5.0 to 20.0 g/10 min, like in the range of 7.0 to 13.0 g/lOmin, like 8.0 to 12.0 g/lOmin.
  • the branched polypropylene (b-PP), i.e. the high melt strength polypropylene (HMS-PP) has
  • melt flow rate MFR 2 (230 °C) of at least 2.0 g/lOmin, preferably in a range of 2.0 to 40.0 g/10 min, more preferably in a range of 4.0 to 30.0 g/10 min, still more preferably in a range of 5.0 to 20.0 g/10 min, yet more preferably in a range of 7.0 to 13.0 g/lOmin, like in a range of 8.0 to 12.0 g/lOmin;
  • the branched polypropylene (b-PP), i.e. the high melt strength polypropylene (HMS-PP), has a melt flow rate MFR 2 (230 °C) of at least 2.0 g/lOmin, a F 30 melt strength of more than 5.8 cN and a V30 melt extensibility of more than 210 to 300 mm/s, like a melt flow rate MFR 2 (230 °C) in a range of 2.0 to 40.0 g/10 min, a F 30 melt strength of more than 5.8 to 20.0 cN and V30 melt extensibility of more than 220 to 300 mm/s, more preferably a melt flow rate MFR 2 (230 °C) in a range of 4.0 to 30.0 g/10 min, a F 30 melt strength of more than 6.0 cN and V30 melt extensibility of more than 225 mm/s, still more preferably a melt flow rate MFR 2 (230 °C) in a range of 5.0 to 20.0
  • the branched polypropylene (b-PP), i.e. the high melt strength polypropylene (HMS-PP), has a melting point of at least 130°C, more preferably of at least 135°C and most preferably of at least 140°C.
  • the crystallization temperature is preferably at least 110 °C, more preferably at least 120 °C.
  • the branched polypropylene i.e. the high melt strength polypropylene (HMS- PP)
  • HMS- PP can be a branched random propylene copolymer (b-R-PP), i.e. a high melt strength random propylene copolymer (R-HMS-PP), or a branched propylene homopolymer (b-H- PP), i.e. a high melt strength propylene homopolymer (H-HMS-PP), the latter being preferred.
  • the expression "propylene homopolymer” refers to a polypropylene that consists substantially, i.e.
  • propylene units in the propylene homopolymer are detectable.
  • the branched polypropylene (b-PP), i.e. the high melt strength polypropylene (HMS- PP), is a branched random propylene copolymer (b-R-PP), i.e. a high melt strength random propylene copolymer (R-HMS-PP), it comprises monomers copolymerizable with propylene, for example comonomers such as ethylene and/or C4 to C12 ⁇ -olefins, in particular ethylene and/or C4 to C10 a-olefins, e.g. 1-butene and/or 1-hexene.
  • the branched random propylene copolymer (b-R-PP) i.e.
  • the high melt strength random propylene copolymer comprises, especially consists of, monomers copolymerizable with propylene from the group consisting of ethylene, 1-butene and 1-hexene. More specifically the branched random propylene copolymer (b-R-PP), i.e. the high melt strength random propylene copolymer (R-HMS-PP), comprises - apart from propylene - units derivable from ethylene and/or 1-butene. In a preferred embodiment the branched random propylene copolymer (b-R-PP), i.e.
  • the high melt strength random propylene copolymer comprises units derivable from ethylene and propylene only.
  • the comonomer content in the branched random propylene copolymer (b-R-PP), i.e. in the high melt strength random propylene copolymer (R-HMS-PP), is preferably in the range of more than 0.2 to 10.0 mol.- %, still more preferably in the range of more than 0.5 to 7.0 mol.-%.
  • the high melt strength polypropylene (HMS-PP) being either a high melt strength propylene homopolymer (H-HMS-PP) or a high melt strength random propylene copolymer (R-HMS-PP) may comprise additionally unsaturated monomers different to the comonomers defined for the high melt strength random propylene copolymer (R-HMS-PP).
  • the high melt strength propylene homopolymer (H- HMS-PP) or the high melt strength random propylene copolymer (R-HMS-PP) may comprise unsaturated units, like bifunctionally unsaturated monomer(s) and/or
  • HMS-PP high melt strength polypropylene
  • PP polypropylene
  • 1-PP linear polypropylene
  • the branched polypropylene (b-PP), i.e. the high melt strength polypropylene (HMS-PP), comprises
  • propylene ii) ethylene and/or C4 to C10 a-olefins, e.g. 1-butene and/or 1-hexene, preferably erthylene, and
  • Bifunctionally unsaturated or “multifunctionally unsaturated” as used above means preferably the presence of two or more non-aromatic double bonds, as in e.g. divinylbenzene or cyclopentadiene or polybutadiene. Only such bi- or multifunctionally unsaturated compounds are used which can be polymerized preferably with the aid of free radicals (see below). The unsaturated sites in the bi- or multifunctionally unsaturated compounds are in their chemically bound state not actually "unsaturated", because the double bonds are each used for a covalent bond to the polymer chains of the unmodified polypropylene, i.e. of the polypropylene (PP), preferably of the linear polypropylene (1-PP).
  • PP polypropylene
  • a thermally free radical forming agent e. g. decomposing free radical-forming agent, like a thermally decomposable peroxide.
  • the bifunctionally unsaturated monomers may be any organic compound having the same functionality as the bifunctionally unsaturated monomers.
  • divinyl compounds such as divinylaniline, m-divinylbenzene, p-divinylbenzene, divinylpentane and divinylpropane;
  • allyl compounds such as allyl acrylate, allyl methacrylate, allyl methyl maleate and allyl vinyl ether;
  • dienes such as 1,3 -butadiene, chloroprene, cyclohexadiene, cyclopentadiene, 2,3- dimethylbutadiene, heptadiene, hexadiene, isoprene and 1 ,4-pentadiene;
  • the multifunctionally unsaturated low molecular weight polymer preferably having a number average molecular weight (M n ) ⁇ 10000 g/mol may be synthesized from one or more unsaturated monomers.
  • 1 ,4-cis, 1 ,4-trans and 1 ,2-(vinyl) are predominantly in the 1 ,2-(vinyl) configuration copolymers of butadiene and styrene having 1,2- (vinyl) in the polymer chain.
  • a preferred low molecular weight polymer is polybutadiene, in particular a polybutadiene having more than 50.0 wt.-% of the butadiene in the l,2-(vinyl) configuration.
  • the branched polypropylene i.e. the high melt strength polypropylene (HMS-PP)
  • HMS-PP high melt strength polypropylene
  • the bifunctionally unsaturated monomer(s) and multifunctionally unsaturated low molecular weight polymer(s) together in the branched polypropylene, i.e. in the high melt strength polypropylene (HMS-PP), is 0.01 to 10.0 wt.-% based on said branched polypropylene, i.e. based on said high melt strength polypropylene (HMS-PP).
  • the branched polypropylene (b-PP), i.e. the high melt strength polypropylene (HMS-PP) is free of additives (A).
  • additives (A) are not brought in the polypropylene composition during the manufacture of the branched polypropylene (b- PP), i.e. of the high melt strength polypropylene (HMS-PP).
  • HMS-PP high melt strength polypropylene
  • the branched polypropylene (b-PP) i.e. the high melt strength polypropylene (HMS-PP)
  • HMS-PP high melt strength polypropylene
  • a modified polypropylene which is obtained by reacting the polypropylene (PP) with a thermally decomposing free radical-forming agent and optionally with bifunctionally unsaturated monomer(s) and/or with multifunctionally unsaturated low molecular weight polymer(s).
  • Essential aspect of the invention is that a specific unmodified polypropylene must be used in the present invention for the manufacture of the branched polypropylene (b-PP), i.e. of the high melt strength polypropylene (HMS-PP), and thus for the manufacture of the polypropylene composition comprising the branched polypropylene (b-PP), i.e. comprising the high melt strength polypropylene (HMS-PP).
  • HMS-PP high melt strength polypropylene
  • polypropylene (PP), preferably the linear polypropylene (1-PP), must have a rather low molecular weight and thus a rather high melt flow rate. Accordingly it is preferred that the polypropylene (PP), preferably the linear polypropylene (1-PP), has a melt flow rate MFR 2 (230°C) measured according to ISO 1133 of more than 1.0 g/lOmin, preferably in the range of more than 1.0 to 18.0 g/lOmin, like of more than 1.0 to 15.0 g/lOmin or of more than 1.1 to 15.0 g/lOmin, more preferably of more than 1.2 to 15.0 g/lOmin or of 1.5 to 15.0 g/lOmin, still more preferably of 2.0 to 15.0 g/lOmin, yet more preferably of 3.0 to 13.0 g/lOmin.
  • MFR 2 melt flow rate measured according to ISO 1133 of more than 1.0 g/lOmin, preferably in the range of more than 1.0 to 18.0 g/l
  • the polypropylene (PP), preferably the linear polypropylene (1-PP), has a melt flow rate MFR 2 (230°C) measured according to ISO 1133 of more than 1.0 g/lOmin, preferably in the range of more than 1.0 to 18.0 g/lOmin, like of more than 1.0 to 15.0 g/lOmin or of more than 1.1 to 15.0 g/lOmin, more preferably of more than 1.2 to 15.0 g/lOmin or of 1.5 to 15.0 g/lOmin, still more preferably of 2.0 to 15.0 g/lOmin, yet more preferably of 3.0 to 13.0 g/lOmin, with the proviso that the value of 10.0 g/lOmin is excluded.
  • MFR 2 melt flow rate measured according to ISO 1133 of more than 1.0 g/lOmin, preferably in the range of more than 1.0 to 18.0 g/lOmin, like of more than 1.0 to 15.0 g/lOmin or of more than 1.1 to
  • the branched polypropylene (b-PP), i.e. the high melt strength polypropylene (HMS-PP), differs from the polypropylene (PP) which is used for its manufacture that the backbone of the branched polypropylene (b-PP), i.e. of the high melt strength polypropylene (HMS-PP), covers side chains whereas the staring product, i.e. the polypropylene (PP), does not cover or nearby does not cover side chains.
  • the side chains have significant impact on the rheology of the polypropylene. Accordingly staring product, i.e. the polypropylene (PP), and the obtained branched polypropylene (b-PP), i.e. the high melt strength polypropylene (HMS- PP), can be clearly distinguished by its flow behavior under stress.
  • the polypropylene (PP) is preferably a linear polypropylene (1- PP).
  • the same considerations apply to the polypropylene ( ⁇ ') as discussed in detail below which is also in a preferred embodiment a linear polypropylene ( ⁇ - ⁇ ').
  • the term "linear polypropylene” indicates that the linear polypropylene, shows no or nearby no-branching structure. Due to the absence of branches, the linear polypropylenes, i.e. the linear polypropylene (1-PP) and the linear polypropylene ( ⁇ - ⁇ '), are preferably featured by a low V30 melt extensibility and/or a low F 30 melt strength.
  • linear polypropylene (1-PP) has
  • a V30 melt extensibility of below 200 mm/s preferably of below 190 mm/s, more preferably in the range of 100 to below 200 mm/s, still more preferably in the range of 120 to 190 mm/s, yet more preferably in the range of 120 to 175 mm/s, like in the range of 125 to 170 mm/s.
  • the linear polypropylene (1-PP) has a F 30 melt strength of more than 1.0 cN and a V30 melt extensibility of below 200 mm/s, preferably a F 30 melt strength of more than 2.0 cN and a V30 melt extensibility of below 190 mm/s, more preferably a F 30 melt strength in the range of 1.0 to 65 cN and a V30 melt extensibility in the range of 100 to below 200 mm/s, yet more preferably a F 30 melt strength in the range of 2.0 to 50 cN and in the range of 120 to 190 mm/s, still yet more preferably a F 30 melt strength in the range of 2.5 to 50 cN and in the range of 120 to 190 mm/s, like a F 30 melt strength in the range of 2.5 to 30 cN and a V30 melt extensibility in the range of 120 to 175 mm/s.
  • the linear polypropylene (1-PP) has
  • melt flow rate MFR 2 (230 °C) measured according to ISO 1133 of more than 1.0 g/lOmin, preferably in the range of more than 1.0 to 18.0 g/lOmin, like of more 1.0 to 15.0 g/1 Omin, more preferably of 1.5 to 15.0 g/1 Omin, still more preferably of 2.0 to 15.0 g/lOmin, yet more preferably of 3.0 to 13.0 g/lOmin;
  • a V30 melt extensibility of below 200 mm/s preferably of below 190 mm/s, more preferably in the range of 100 to below 200 mm/s, still more preferably in the range of 120 to 190 mm/s, yet more preferably in the range of 120 to 175 mm/s, like in the range of 125 to 170 mm/s.
  • the polypropylene (PP) is a linear polypropylene (1- PP) having a melt flow rate MFR 2 (230 °C) of more than 1.0 g/1 Omin, a F 30 melt strength of more than 1.0 cN and a V30 melt extensibility of below 200 mm/s, preferably a melt flow rate MFPv 2 (230 °C) in the range of more than 1.0 to 18.0 g/1 Omin, a F 30 melt strength of more than 2.0 cN and a V30 melt extensibility of below 190 mm/s, more preferably a melt flow rate MFPv 2 (230 °C) in the range of more 1.0 to 15.0 g/1 Omin, a F 30 melt strength in the range of 1.0 to 65 cN and a V30 melt extensibility in the range of 100 to below 200 mm/s, yet more preferably a melt flow rate MFR 2 (230 °C) in the range of more 1.5 to 15.0 g/1 Omin
  • polypropylene (PP), preferably the linear polypropylene (1-PP), is used in form of particles of specific size. Accordingly it is preferred that the polypropylene (PP), preferably the linear polypropylene (1-PP), has
  • the polypropylene (PP), preferably the linear polypropylene (1-PP), can be produced in a known manner for instance by employing a single-site or a Ziegler Natta catalyst.
  • the polypropylene (PP), preferably the linear polypropylene (1-PP) can be a propylene homopolymer (H-PP), preferably a linear propylene homopolymer (1-H-PP), or a propylene copolymer (R-PP), preferably a linear propylene copolymer (1-R-PP).
  • the polypropylene (PP) is a linear polypropylene (1-PP).
  • the polypropylene (PP) is a linear propylene homopolymer (1-H-PP). Accordingly all information provided with regard to melt flow rate MFR 2 (230°C), melting point, F 30 melt strength, V30 melt extensibility, and particle size and particle size distribution, respectively, applies especially for the linear propylene homopolymer (1-H-PP).
  • the polypropylene (PP), preferably the linear polypropylene (1- PP), is free of additives (A). Accordingly in case the instant polypropylene composition comprises additives (A), these additives (A) are not brought in the polypropylene composition during the manufacture of the branched polypropylene (b-PP), i.e. of the high melt strength polypropylene (HMS-PP).
  • HMS-PP high melt strength polypropylene
  • a further polypropylene ( ⁇ ') may be added.
  • This polypropylene ( ⁇ ') is preferably used to bring additives (A) in the instant polypropylene composition. It is a further finding of the present invention that especially good results in view of optical properties, i.e. in terms of low gel index, are achieved for the instant polypropylene composition if the additives (A) are brought in by use of a specific polypropylene carrier. Accordingly in a preferred embodiment the additives (A) are introduced in the instant polypropylene composition in the form of an additive mixture (AM), wherein said additive mixture comprises, preferably consists of, the polypropylene ( ⁇ ') and the additives (A).
  • AM additive mixture
  • polypropylene (PP') > is a linear polypropylene ( ⁇ - ⁇ ').
  • MFPv 2 melt flow rate measured according to ISO 1133 of more than 1.0 g/lOmin, preferably in the range of more than 1.0 to 18.0 g/lOmin, like of more 1.0 to 15.0 g/lOmin, more preferably of 1.5
  • the polypropylene ( ⁇ ') is preferably a linear polypropylene (1- PP') and thus shows no or nearby no-branching structure. Due to the absence of branches the linear polypropylene ( ⁇ - ⁇ ') is preferably featured by a low V30 melt extensibility and/or a low F 30 melt strength. Thus it is preferred that the linear polypropylene ( ⁇ - ⁇ ') has
  • a V30 melt extensibility of below 200 mm/s preferably of below 190 mm/s, more preferably in the range of 100 to below 200 mm/s, still more preferably in the range of 120 to 190 mm/s, yet more preferably in the range of 120 to 175 mm/s, like in the range of 125 to 170 mm/s.
  • the linear polypropylene ( ⁇ - ⁇ ') has a F 30 melt strength of more than 1.0 cN and a V30 melt extensibility of below 200 mm/s, preferably a F 30 melt strength of more than 2.0 cN and a V30 melt extensibility of below 190 mm/s, more preferably a F 30 melt strength in the range of 1.0 to 65 cN and a V30 melt extensibility in the range of 100 to below 200 mm/s, yet more preferably a F 30 melt strength in the range of 2.0 to 50 cN and in the range of 120 to 190 mm/s, still yet more preferably a F 30 melt strength in the range of 2.5 to 50 cN and in the range of 120 to 190 mm/s, like a F 30 melt strength in the range of 2.5 to 30 cN and a V30 melt extensibility in the range of 120 to 175 mm/s.
  • the linear polypropylene ( ⁇ - ⁇ ') has a melt flow rate MFR 2 (230 °C) measured according to ISO 1133 of more than 1.0 g/lOmin, preferably in the range of more than 1.0 to 18.0 g/lOmin, like of more 1.0 to 15.0 g/1 Omin, more preferably of 1.5 to 15.0 g/1 Omin, still more preferably of 2.0 to 15.0 g/lOmin, yet more preferably of 3.0 to 13.0 g/lOmin;
  • V30 melt extensibility of below 200 mm/s preferably of below 190 mm/s, more preferably in the range of 100 to below 200 mm/s, still more preferably in the range of 120 to 190 mm/s, yet more preferably in the range of 120 to 175 mm/s, like in the range of 125 to 170 mm/s.
  • the polypropylene ( ⁇ ') is a linear polypropylene (1- PP') having a melt flow rate MFR 2 (230 °C) of more than 1.0 g/1 Omin, a F 30 melt strength of more than 1.0 cN and a V30 melt extensibility of below 200 mm/s, preferably a melt flow rate MFPv 2 (230 °C) in the range of more than 1.0 to 18.0 g/1 Omin, a F 30 melt strength of more than 2.0 cN and a V30 melt extensibility of below 190 mm/s, more preferably a melt flow rate MFPv 2 (230 °C) in the range of more 1.0 to 15.0 g/1 Omin, a F 30 melt strength in the range of 1.0 to 65 cN and a V30 melt extensibility in the range of 100 to below 200 mm/s, yet more preferably a melt flow rate MFR 2 (230 °C) in the range of more 1.5 to 15.0 g/l
  • the polypropylene (PP') > preferably the linear polypropylene ( ⁇ - ⁇ '), is used in form of particles of specific size. Accordingly it is preferred that the polypropylene (PP') > preferably the linear polypropylene ( ⁇ - ⁇ '), has (a) a particle size distribution dw of below 1,500 ⁇ ; more preferably below 1,000 ⁇ , still more preferably in the range of 50 to below 1,000 ⁇ , yet more preferably in the range of 100 to 800 ⁇ , like in the range of 150 to 600 ⁇ ;
  • the polypropylene (PP') > preferably the linear polypropylene ( ⁇ - ⁇ '), can be produced in a known manner for instance by employing a single-site or a Ziegler Natta catalyst.
  • the polypropylene ( ⁇ '), preferably the linear polypropylene ( ⁇ - ⁇ '), can be a propylene homopolymer ( ⁇ - ⁇ '), preferably a linear propylene homopolymer ( ⁇ - ⁇ - ⁇ '), or a propylene copolymer (R-PP'), preferably a linear propylene copolymer (1-R-PP').
  • the polypropylene ( ⁇ ') is a linear polypropylene ( ⁇ - ⁇ ').
  • the polypropylene ( ⁇ ') is a linear propylene homopolymer ( ⁇ - ⁇ - ⁇ '). Accordingly all information provided with regard to melt flow rate MFR 2 (230°C), melting point, F 30 melt strength, V30 melt extensibility, and particle size and particle size distribution, respectively, applies especially for the linear propylene homopolymer ( ⁇ - ⁇ - ⁇ ').
  • polypropylene (PP) and the polypropylene ( ⁇ ') are the same.
  • the polypropylene (PP) and the polypropylene ( ⁇ ') are linear propylene homopolymers, i.e. a linear propylene homopolymer (1-H-PP) and a linear propylene homopolymer ( ⁇ - ⁇ - ⁇ '), with the same properties, in particular in view of melt flow rate MFR 2 (230 °C), F 30 melt strength and V30 melt extensibility as discussed above.
  • the polypropylene ( ⁇ ') is used as a carrier to introduce the additives (A) in the polypropylene composition.
  • an additive mixture (AM) comprising, preferably consisting of, the polypropylene ( ⁇ ') and the additives (A) is used in the instant process for the manufacture of the polypropylene composition.
  • the additives (A) can be any additives useful in the technical area of the high melt strength polypropylene (HMS-PP) and its applications. Accordingly the additives (A) to be used in the polypropylene composition of the invention and thus in form of the additive mixture (AM) include, but are not limited to, stabilizers such as antioxidants (e.g. sterically hindered phenols, phosphites/phosphonites, sulphur containing antioxidants, alkyl radikal scavangers, aromatic amines, hindered amine stabilizers, or blends thereof), metal deactivators (e.g. Irganox MD 1024), or UV stabilizers (e.g. hindered amine light stabilizers).
  • stabilizers such as antioxidants (e.g. sterically hindered phenols, phosphites/phosphonites, sulphur containing antioxidants, alkyl radikal scavangers, aromatic amines, hindered amine stabilizer
  • modifiers such as antistatic or antifogging agents (e.g. ethoxylated amines and amides, or glycerol esters), acid scavengers (e.g. Ca-stearate), blowing agents, cling agents (e.g. polyisobutene), lubriciants and resins (ionomer waxes, PE- and ethylene copolymer waxes, Fischer-Tropsch waxes, Montan-based waxes, Fluoro-based compounds, or paraffin waxes), nucleating agents (e.g.
  • antistatic or antifogging agents e.g. ethoxylated amines and amides, or glycerol esters
  • acid scavengers e.g. Ca-stearate
  • blowing agents e.g. polyisobutene
  • cling agents e.g. polyisobutene
  • lubriciants and resins ionomer
  • talc benzoates, phosphorous-based compounds, sorbitoles, nonitol-based compounds, or amide-based compounds), as well as slip and antiblocking agents (e.g. erucamide, oleamide, talc natural silica and synthetic silica, or zeolites).
  • slip and antiblocking agents e.g. erucamide, oleamide, talc natural silica and synthetic silica, or zeolites.
  • the additives (A) are selected from the group consisting of antioxidants (e.g. sterically hindered phenols, phosphites/phosphonites, sulphur containing antioxidants, alkyl radikyl scavangers, aromatic amines, hindered amine stabilizers, or blends thereof), metal deactivators (e.g. Irganox MD 1024), or UV stabilizers (e.g. hindered amine light stabilizers), antistatic or antifogging agents (e.g. ethoxylated amines and amides, or glycerol esters), acid scavengers (e.g. Ca-stearate), blowing agents, cling agents (e.g.
  • antioxidants e.g. sterically hindered phenols, phosphites/phosphonites, sulphur containing antioxidants, alkyl radikyl scavangers, aromatic amines, hindered amine stabilizers
  • polyisobutene polyisobutene
  • lubriciants and resins ionomer waxes, PE- and ethylene copolymer waxes, Fischer-Tropsch waxes, Montan-based waxes, Fluoro-based compounds, or paraffin waxes
  • nucleating agents e.g. talc, benzoates, phosphorous-based compounds, sorbitoles, nonitol-based compounds, or amide-based compounds
  • slip agents e.g. erucamide, oleamide, talc natural silica and synthetic silica, or zeolites
  • antiblocking agents e.g. erucamide, oleamide, talc natural silica and synthetic silica, or zeolites
  • the total amount of additives (A) in the additive mixture (AM) is not more than 25 wt.-%, more preferably not more than 20 wt.-%, like in the range of 5 to 20 wt.-% based on the total weight of the additive mixture (AM).
  • polypropylene composition which comprises a branched polypropylene (b-PP), i.e. a high melt strength polypropylene (HMS-PP).
  • the instant polypropylene composition comprises a branched polypropylene (b-PP), i.e. a high melt strength polypropylene (HMS-PP), a polypropylene (PP') > preferably a linear polypropylene ( ⁇ - ⁇ '), and optionally at least one additive (A).
  • the major component in the instant polypropylene composition is the branched
  • the polypropylene composition comprises at least 70 wt.-%, more preferably at least 75 wt.-%, yet more preferably at least 80 wt.-%, still more preferably at least 85 wt.-%, still yet more preferably at least 90 wt.-%, like at least 95 wt.-%, of the branched polypropylene (b-PP), i.e. the high melt strength polypropylene (HMS-PP).
  • the instant polypropylene composition comprises
  • polypropylene (b) 1 to 20 parts by weight, preferably 1 to 10 parts by weight, more preferably 1 to 5 parts by weight, of polypropylene (PP') > preferably of the linear polypropylene (1- PP').
  • branched polypropylene (b-PP) i.e. the high melt strength polypropylene (HMS-PP)
  • polypropylene ( ⁇ ') preferably the linear polypropylene ( ⁇ - ⁇ ')
  • HMS-PP high melt strength polypropylene
  • ⁇ ' preferably the linear polypropylene ( ⁇ - ⁇ ')
  • polypropylene composition may comprise further at least one additive (A) as defined in more detail above but no other polymers in an amount exceeding 5 wt.-%, more preferably exceeding 2 wt.-%, still more preferably exceeding 1 wt.-%, based on the total weight of the polypropylene composition.
  • polypropylene composition consists of the branched polypropylene (b-PP), i.e. the high melt strength polypropylene (HMS-PP), the polypropylene ( ⁇ '), preferably the linear polypropylene ( ⁇ - ⁇ '), and at least one additive (A).
  • the total amount of additives (A) in the polypropylene composition is not more 5.0 wt.-%, more preferably not more than 1.0 wt.-%, like in the range of 0.005 to 0.5 wt.-%, based on the total weight of the polypropylene composition.
  • additives (A) optionally 0.005 to 5.0, preferably 0.005 to 2.0, more preferably 0.05 to 1.0, like 0.05 to 0.5, parts by weight of additives (A), wherein said additives(A) are preferably selected from the group consisting of antioxidants, metal deactivators, UV-stabilizers, antistatic agents, antifogging agents, acid scavengers, blowing agents, cling agents, lubricants, nucleating agents, slip agents, antiblocking agents and mixtures thereof.
  • the branched polypropylene (b-PP) i.e the high melt strength polypropylene (HMS-PP)
  • HMS-PP high melt strength polypropylene
  • the final polypropylene composition shows a similar rheology behavior as the branched polypropylene (b-PP), i.e. the high melt strength polypropylene (HMS-PP).
  • the instant polypropylene composition has a F 30 melt strength of more than 5.8 cN and a V30 melt extensibility of more than 210 to 300 mm/s, like a F 30 melt strength of more than 5.8 to 20.0 cN and V30 melt extensibility of more than 220 to 300 mm/s, more preferably a F 30 melt strength of more than 6.0 cN and V30 melt extensibility of more than 225 mm/s, still more preferably a F 30 melt strength of 6.0 to 18.0 cN and V30 melt extensibility of 225 to 300 mm/s, yet more preferably a F 30 melt strength of 6.2 to 15.0 cN and V30 melt extensibility of 230 to 290 mm/s, still yet more preferably a F 30 melt strength of 6.2 to 13.0 cN and V30 melt extensibility of 230 to 290 mm/s, most preferably a F 30 melt strength of 6.0 to 12.0 cN and V30 melt extensibility of 210 to
  • the instant polypropylene composition can be further defined by the strain hardening factor (SHF). Accordingly it is preferred that the instant polypropylene composition has a strain hardening factor (SHF) of at least 1.7, more preferably of at least 1.9, yet more preferably in the range of 1.9 to 7.0, still more preferably in the range of 1.9 to 6.5 measured at a strain rate of 3.0 s "1 and a Hencky strain of 2.5.
  • SHF strain hardening factor
  • the instant polypropylene composition has a melt flow rate MFR 2 (230 °C) measured according to ISO 1133 of at least 2.0 g/lOmin, more preferably in a range of 2.0 to 40.0 g/10 min, still more preferably in a range of 4.0 to 30.0 g/10 min, yet more preferably in a range of 5.0 to 20.0 g/10 min, like in the range of 7.0 to 13.0 g/lOmin, like 8.0 to 12.0 g/lOmin.
  • the instant polypropylene composition has
  • melt flow rate MFR 2 (230 °C) of at least 2.0 g/lOmin, preferably in a range of 2.0 to 40.0 g/10 min, more preferably in a range of 4.0 to 30.0 g/10 min, still more preferably in a range of 5.0 to 20.0 g/10 min, yet more preferably in a range of 7.0 to 13.0 g/lOmin, like in a range of 8.0 to 12.0 g/lOmin;
  • the instant polypropylene composition has a melt flow rate MFR 2 (230 °C) of at least 2.0 g/lOmin, a F 30 melt strength of more than 5.8 cN and a V30 melt extensibility of more than 210 to 300 mm/s, like a melt flow rate MFR 2 (230 °C) in a range of 2.0 to 40.0 g/10 min, a F 30 melt strength of more than 5.8 to 20.0 cN and V30 melt extensibility of more than 220 to 300 mm/s, more preferably a melt flow rate MFR 2 (230 °C) in a range of 4.0 to 30.0 g/10 min, a F 30 melt strength of more than 6.0 cN and V30 melt extensibility of more than 225 mm/s, still more preferably a melt flow rate MFR 2 (230 °C) in a range of 5.0 to 20.0 g/10 min, a F 30 melt strength of 6.0 to 18.0 cN and V30
  • the instant polypropylene composition and thus films made from said polypropylene composition show a reduced OCS gel index. Accordingly it is preferred that the instant polypropylene composition has OCS gel index of less than 1,000, preferably of less than 800, more preferably less than 500, still more preferably in the range of 5 to 800, yet more preferably in the range of 10 to 300, still yet more preferably in the range of 10 to 200.
  • additives (A) optionally 0.005 to 5.0, preferably 0.005 to 2.0, more preferably 0.05 to 1.0, like 0.05 to 0.5, parts by weight of additives (A), wherein said additives(A) are preferably selected from the group consisting of antioxidants, metal deactivators, UV-stabilizers, antistatic agents, antifogging agents, acid scavengers, blowing agents, cling agents, lubricants, nucleating agents, slip agents, antiblocking agents and mixtures thereof;
  • melt flow rate MFR 2 (230 °C) of at least 2.0 g/lOmin, preferably in a range of 2.0 to 40.0 g/10 min, more preferably in a range of 4.0 to 30.0 g/10 min, still more preferably in a range of 5.0 to 20.0 g/10 min, yet more preferably in a range of 7.0 to 13.0 g/lOmin, like in a range of 8.0 to 12.0 g/lOmin; and
  • OCS gel index of less than 1,000, preferably of less than 800, more preferably less than 500, still more preferably in the range of 5 to 800, yet more preferably in the range of 10 to 300, still yet more preferably in the range of 10 to 200;
  • V30 melt extensibility of more than 210 to 300 mm/s, like of more than 220 to 300 mm/s, more preferably of more than 225 mm/s, still more preferably of 225 to 300 mm/s, yet more preferably of 230 to 290 mm/s.
  • the present invention also features a film comprising the instant polypropylene composition described herein.
  • the film is a cast film or a blown film.
  • the film may also be a biaxially oriented film, like biaxially oriented blown film.
  • the differences between such films are known to the skilled person. Reference is made in this regard to the "Polypropylene Handbook", pages 405 to 414, 2 nd Edition, Nello Pasquini (Ed.), Hanser.
  • the film comprises at least 70 wt.-%, more preferably at least 80 wt.-%, more preferably at least 90 wt.-%, yet more preferably at least 95 wt.-%, of the polypropylene composition according to the instant invention.
  • the film consists of the instant polypropylene composition.
  • One essential aspect of the present invention is that the manufacture of the polypropylene composition comprising the branched polypropylene (b-PP), i.e. comprising the high melt strength polypropylene (HMS-PP), by using the polypropylene (PP), preferably the linear polypropylene (1-PP).
  • b-PP branched polypropylene
  • HMS-PP high melt strength polypropylene
  • the present invention relates to a process for providing a polypropylene composition comprising the branched polypropylene (b-PP), wherein the process comprises at least a step (a) in which a polypropylene (PP) is reacted with a thermally decomposing free radical-forming agent and optionally with biiunctionally unsaturated monomer(s) and/or with multifunctionally unsaturated low molecular weight polymer(s) obtaining thereby the branched polypropylene (b-PP).
  • the instant process comprises subsequent to step (a) a further step (b), in which to the branched polypropylene (b-PP), i.e.
  • the instant process comprises subsequent to step (a) a further step (b), in which to the branched polypropylene (b-PP), i.e. to the high melt strength polypropylene (HMS-PP), the additive mixture (AM) comprising the polypropylene ( ⁇ ') and the additives (A) is added.
  • a further step (b) in which to the branched polypropylene (b-PP), i.e. to the high melt strength polypropylene (HMS-PP), the additive mixture (AM) comprising the polypropylene ( ⁇ ') and the additives (A) is added.
  • step (a) the branched polypropylene (b-PP), i.e. the high melt strength polypropylene (HMS-PP), is obtained by treating the polypropylene (PP), preferably the linear polypropylene (1-PP), with thermally decomposing radical-forming agents.
  • PP polypropylene
  • PP linear polypropylene
  • polypropylene preferably the linear polypropylene (PP)
  • PP polypropylene
  • the chemical modification is accomplished by the additional use of bifunctionally unsaturated monomer(s) and/or multifunctionally unsaturated low molecular weight polymer(s) as chemically bound bridging unit(s).
  • a suitable method to obtain the branched polypropylene (b-PP), i.e. the high melt strength polypropylene (HMS-PP), is for instance disclosed in EP 0 787 750,
  • the amount of thermally decomposing radical-forming agents is preferably in the range of 0.05 to 3.00 wt.-% based on the amount of the polypropylene (PP).
  • the thermally decomposing radical-forming agents are added together with the bifunctionally unsaturated monomer(s) and/or with multifunctionally unsaturated low molecular weight polymer(s) to the polypropylene (PP), preferably to the linear polypropylene (1-PP).
  • PP polypropylene
  • the bifunctionally unsaturated monomer(s) and/or multifunctionally unsaturated low molecular weight polymer(s) is/are added to the polypropylene (PP), preferably to the linear polypropylene (1-PP), and subsequent the thermally decomposing radical- forming agents, or the other way round,
  • the thermally decomposing radical-forming agents are added to the polypropylene (PP), preferably to the linear polypropylene (1-PP), and subsequent the bifunctionally unsaturated monomer(s) and/or multifunctionally unsaturated low molecular weight polymer(s).
  • branched polypropylene i.e. the high melt strength polypropylene (HMS-PP)
  • HMS-PP high melt strength polypropylene
  • bifunctionally unsaturated monomer(s) and/or multifunctionally unsaturated low molecular weight polymer(s) are used in the presence of a thermally decomposing free radical-forming agent.
  • Peroxides are preferred thermally decomposing free radical- forming agents. More preferably the thermally decomposing free radical-forming agents are selected from the group consisting of acyl peroxide, alkyl peroxide, hydroperoxide, perester and peroxycarbonate.
  • Acyl peroxides benzoyl peroxide, 4-chlorobenzoyl peroxide, 3-methoxybenzoyl peroxide and/or methyl benzoyl peroxide.
  • Alkyl peroxides allyl t-butyl peroxide, 2,2-bis(t-butylperoxybutane), l,l-bis(t- butylperoxy)-3,3,5-trimethylcyclohexane, n-butyl-4,4-bis(t-butylperoxy) valerate, diisopropylaminomethyl-t-amyl peroxide, dimethylaminomethyl-t-amyl peroxide, diethylaminomethyl-t-butyl peroxide, dimethylaminomethyl-t-butyl peroxide, 1 , 1 -di-(t- amylperoxy)cyclohexane, t-amyl peroxide, t-butylcumyl peroxide, t-butyl peroxide and/or 1- hydroxybutyl n-butyl peroxide.
  • Peresters and peroxy carbonates butyl peracetate, cumyl peracetate, cumyl perpropionate, cyclohexyl peracetate, di-t-butyl peradipate, di-t-butyl perazelate, di-t-butyl perglutarate, di-t-butyl perthalate, di-t-butyl persebacate, 4-nitrocumyl perpropionate, 1 - phenylethyl perbenzoate, phenylethyl nitro-perbenzoate, t-butylbicyclo-(2,2, 1 )heptane percarboxylate, t-butyl-4-carbomethoxy perbutyrate, t-butylcyclobutane percarboxylate, t- butylcyclohexyl peroxycarboxylate, t-butylcyclopentyl percarboxylate, t-butylcyclopropane percarboxylate
  • step (b) is initiated when at least 70 %, preferably at least 80 %, yet more preferably at least 90 %, like at least 95 or 99 %, of the reaction between the polypropylene (PP) and the thermally decomposing free radical- forming agent and optionally the bifunctionally unsaturated monomer has taken place to obtain the branched polypropylene (b-PP), i.e. the high melt strength polypropylene (HMS-PP).
  • an extruder such as a twin screw extruder, is used for step (a) and (b).
  • extruder is particularly advantageous in that it can simultaneously be used for the preparation of the branched propylene (b-PP), i.e. the high melt strength polypropylene (HMS-PP), and subsequent for adding the polypropylene ( ⁇ ') or for adding the additive mixture (AM) to said branched propylene (b-PP).
  • HMS-PP high melt strength polypropylene
  • AM additive mixture
  • the polypropylene (PP) is added to an extruder together with - as described in detail above - the thermally decomposing free radical-forming agent, preferably a peroxide, and optionally with the bifunctionally unsaturated monomer(s) and/or with the multifunctionally unsaturated low molecular weight polymer(s), preferably with the bifunctionally unsaturated monomer(s) selected from divinyl compounds, allyl compounds or dienes, to provide the branched polypropylene (b-PP), i.e. the high melt strength polypropylene (HMS-PP), in step (a).
  • the thermally decomposing free radical-forming agent preferably a peroxide
  • the bifunctionally unsaturated monomer(s) and/or with the multifunctionally unsaturated low molecular weight polymer(s) preferably with the bifunctionally unsaturated monomer(s) selected from divinyl compounds, allyl compounds or dienes, to provide the branched polypropylene (b-PP), i.e
  • b-PP i.e. the high melt strength polypropylene
  • the term "downstream end of the extruder screw” is understood as within the last 60 % of the length of the extruder screw, preferably within the last 65 % of the length of the extruder screw, more preferably at least 70 % of the length of the extruder screw, like at least 75 % of the extruder screw.
  • the extruder (E) used for the instant process preferably comprises in operation direction a feed-throat (FT), a first mixing zone (MZl), a second mixing zone (MZ2) and a die (D), wherein between the first mixing zone (MZl) and the second mixing zone (MZ2) a side feed-throat (SFT) is located.
  • FT feed-throat
  • MZl first mixing zone
  • MZ2 second mixing zone
  • D die
  • the extruder is a screw extruder, like a twin screw extruder.
  • the polypropylene (PP), the thermally decomposing free radical- forming agent, preferably a peroxide, and optionally the bifunctionally unsaturated monomer and/or the multifunctionally unsaturated low molecular weight polymer monomer, preferably selected from divinyl compounds, allyl compounds or dienes, but not the polypropylene (PP') > ⁇ not the linear polypropylene ( ⁇ - ⁇ '), and not the additives (A), are fed via the feed-throat (FT), thereby preferably using a feeder, into the extruder and is/are subsequently passed downstream through the first mixing zone (MZl).
  • FT feed-throat
  • MZl first mixing zone
  • the shear stress in said first mixing zone (MZl) is of such extent that the polypropylene (PP) is molten and the chemical reaction with the radical- forming agent and with the optional bifunctionally unsaturated monomer and/or multifunctionally unsaturated low molecular weight polymer is initiated.
  • the polypropylene ( ⁇ '), preferably the linear polypropylene (1- PP'), or the additive mixture (AM) is added, i.e. fed into the extruder.
  • the polypropylene (PP') > preferably the linear polypropylene ( ⁇ - ⁇ '), or the additive mixture (AM) is added via the side feed-throat (SFT), thereby preferably using a side feeder.
  • the polypropylene composition including the polypropylene ( ⁇ '), preferably the linear polypropylene ( ⁇ - ⁇ '), or the additive mixture (AM) are passed downstream through the second mixing zone (MZ2). Finally the polypropylene composition is discharged via the die (D).
  • the first mixing zone (MZl) is longer than the second mixing zone (MZ2).
  • the length ratio between the first mixing zone (MZl) to the second mixing zone (MZ2) [mm (MZl) / mm (MZ2)] is at least 2/1, more preferably 3/1, yet more preferably in the range of 2/1 to 15/1, still more preferably 3/1 to 10/1.
  • the preparation of the films is accomplished known in the art.
  • the film can be produced by cast film or blown film technology. In the cast film technology the molten polypropylene composition is extruded through a slot extrusion die onto a chill roll to cool the polymer to a solid film.
  • the polypropylene composition is firstly compressed and liquefied in an extruder, it being possible for any additives to be already added to the polymer or introduced at this stage via a masterbatch.
  • the melt is then forced through a flat- film die (slot die), and the extruded film is taken off on one or more take-off rolls, during which it cools and solidifies. It has proven particularly favorable to keep the take-off roll or rolls, by means of which the extruded film is cooled and solidified, at a temperature from 10 to 50 °C, preferably from 10 to 40 °C, more preferably from 12 to 35 °C.
  • the obtained product is an unstretched film which can if desired biaxially stretched.
  • the polypropylene composition is extruded through an annular die and blown into a tubular film by forming a bubble which is collapsed between nip rollers after solidification.
  • the blown extrusion can be preferably effected at a temperature in the range 160 to 240 °C, and cooled by water or preferably by blowing gas (generally air) at a temperature of 10 to 50 °C to provide a frost line height of 0.5 to 8 times the diameter of the die.
  • the blow up ratio should generally be in the range of from 1.5 to 4, such as from 2 to 4, preferably 2.5 to 3.5.
  • the comonomer content is determined by quantitative Fourier transform infrared spectroscopy (FTIR) after basic assignment calibrated via quantitative 13 C nuclear magnetic resonance (NMR) spectroscopy in a manner well known in the art. Thin films are pressed to a thickness of 250 ⁇ and spectra recorded in transmission mode.
  • FTIR quantitative Fourier transform infrared spectroscopy
  • NMR quantitative 13 C nuclear magnetic resonance
  • the ethylene content of a polypropylene-co-ethylene copolymer is determined using the baseline corrected peak area of the quantitative bands found at 720-722 and 730- 733 cm “1 .
  • Propylene- 1 -butene-copolymers were evaluated at 767 cm "1 . Quantitative results are obtained based upon reference to the film thickness.
  • MFR 2 (230 °C) is measured according to ISO 1133 (230 °C, 2.16 kg load).
  • SHF Strain hardening factor
  • the strain hardening factor is defined as ⁇ ⁇ + ⁇ ( ⁇ 3 ⁇ + ( ⁇
  • r ⁇ g(t, s) is the uniaxial extensional viscosity; and ⁇ + (t) is three times the time dependent shear viscosity r ⁇ + (t) in the linear range of deformation.
  • Hub 2008 required the calculation of the discrete relaxation time spectrum from the storage and loss modulus data (G', G" ( ⁇ )).
  • the linear viscoelastic data (G', G" ( ⁇ )) is obtained by frequency sweep measurements undertaken at 180 °C for polypropylene or at 140 ° for polyethylene , on a Anton Paar MCR 300 coupled with 25 mm parallel plates.
  • the underlying calculation principles used for the determination of the discrete relaxation spectrum are described in Baumgartel M, Winter HH, "Determination of the discrete relaxation and retardation time spectra from dynamic mechanical data", Rheol.Acta
  • IRIS RheoHub 2008 expresses the relaxation time spectrum as a sum of N Maxwell modes o N -—
  • N used for determination of the discrete relaxation spectrum.
  • the choice for the maximum number of modes, N used for determination of the discrete relaxation spectrum, is done by using the option "optimum" from IRIS RheoHub 2008.
  • the equilibrium modulus G e was set at zero.
  • the non- linear fitting used to obtain ⁇ + (?) is performed on IRIS Rheo Hub 2008, using the Doi-Edwards model.
  • the uniaxial extensional viscosity, ⁇ ( ⁇ , ⁇ ) is obtained from uniaxial extensional flow measurements, conducted on an Anton Paar MCR 501 coupled with the Sentmanat extensional fixture (SER-1).
  • the temperature for the uniaxial extensional flow measurements was set at 180°C, applying extension (strain) rates ⁇ /dt ranging from 0.3 s "1 to 10 s "1 and covering a range of Hencky strain
  • the strain hardening behaviour is determined by the method as described in the article "Rheotens-Mastercurves and Drawability of Polymer Melts", M. H. Wagner, Polymer Engineering and Sience, Vol. 36, pages 925 to 935. The content of the document is included by reference.
  • the strain hardening behaviour of polymers is analysed by Rheotens apparatus (product of Gottfert, Siemensstr.2, 74711 Buchen, Germany) in which a melt strand is elongated by drawing down with a defined acceleration.
  • the Rheotens experiment simulates industrial spinning and extrusion processes.
  • a melt is pressed or extruded through a round die and the resulting strand is hauled off.
  • the stress on the extradate is recorded, as a function of melt properties and measuring parameters (especially the ratio between output and haul-off speed, practically a measure for the extension rate).
  • the gear pump was pre-adjusted to a strand extrusion rate of 5 mm/s, and the melt temperature was set to 200°C.
  • the spinline length between die and Rheotens wheels was 80 mm.
  • the take-up speed of the Rheotens wheels was adjusted to the velocity of the extruded polymer strand (tensile force zero): Then the experiment was started by slowly increasing the take-up speed of the Rheotens wheels until the polymer filament breaks. The acceleration of the wheels was small enough so that the tensile force was measured under quasi-steady conditions. The acceleration of the melt strand drawn down is 120 mm/sec 2 .
  • the Rheotens was operated in combination with the PC program EXTENS. This is a real-time data-acquisition program, which displays and stores the measured data of tensile force and drawdown speed. The end points of the Rheotens curve (force versus pulley rotary speed) is taken as the F 30 melt strength and drawability values.
  • the apparatus consists of a laboratory extruder ME 25/5200 VI with three heating zones, an adapter and a 150 mm broad die.
  • the follow-on unit encompasses a chillroll CR - 8, diameter 140 mm, including Haake C40P heating- and cooling device (15 to 90 °C), a line scan camera FS -5 / 4096 Pixel (dynamical digital converting of gray scale images) and a wind-up unit with automatic tension control up to 10 N.
  • the temperature setting for the heating zones at cylinder and die is classified for polypropylene according to MFR-ranges in three groups:
  • Group 1 MFR-range 0.3-2.0 g/10 min (230 °C/2.16 kg), temperatures
  • Group 2 MFR-range 2.0-10 g/10 min (230 °C/2.16 kg), temperatures
  • Group 3 MFR-range 10-33 g/10 min (230 °C/2.16 kg), temperatures
  • the film thickness is 50 ⁇
  • the number of found defects is, referring 1/m 2 , class-divided according to size and multiplied with the mass factor, adding up to the gelindex.
  • Size class 1 100-300 ⁇ mass factor x 0.1
  • Size class 2 301-600 ⁇ mass factor x 1.0
  • Size class 3 601-1000 ⁇ mass factor x 5.0
  • Size class 4 > 1000 ⁇ mass factor x 10
  • a gradation test was performed on the polymer samples.
  • the sieve analysis involved a nested column of sieves with wire mesh screen with the following sizes: >20 ⁇ , >32 ⁇ , >63 ⁇ , >100 ⁇ , >125 ⁇ , >160 ⁇ , > 200 ⁇ , >250 ⁇ , > 315 ⁇ , > 400 ⁇ , >500 ⁇ , >710 ⁇ , >1 mm, >1.4 mm, > 2 mm, >2.8 mm.
  • the samples were poured into the top sieve which has the largest screen openings. Each lower sieve in the column has smaller openings than the one above (see sizes indicated above).
  • At the base is the receiver.
  • the column was placed in a mechanical shaker. The shaker shook the column. After the shaking was completed the material on each sieve was weighed. The weight of the sample of each sieve was then divided by the total weight to give a percentage retained on each sieve.
  • 1-PPl is a linear propylene homopolymer having a MFR 2 (230°C) of 0.37 g/lOmin, a d 5 o of 1,100 ⁇ , a dgo of 1,650 ⁇ , a melting temperature Tm of 164 °C, a F 30 melt strength of 68 cN and V30 melt extensibility 146 mm/s.
  • 1-PP2 is a linear propylene homopolymer having a MFR 2 (230°C) of 3.48 g/lOmin, a d 5 o of 220 ⁇ , a dgo of 300 ⁇ , a melting temperature Tm of 160 °C, a F 30 melt strength of 6.5 cN and V30 melt extensibility 160 mm/s.
  • 1-PP3 is a linear propylene homopolymer having a MFR 2 (230°C) of 3.39 g/lOmin, a d 5 o of 700 ⁇ , a dgo of 1,100 ⁇ , a melting temperature Tm of 159 °C, a F 30 melt strength of 8.2 cN and V30 melt extensibility 155 mm/s.
  • Additive mixture a linear propylene homopolymer having a MFR 2 (230°C) of 3.39 g/lOmin, a d 5 o of 700 ⁇ , a dgo of 1,100 ⁇ , a melting temperature Tm of 159 °C, a F 30 melt strength of 8.2 cN and V30 melt extensibility 155 mm/s.
  • the linear polypropylenes 1-PP2 was used to provide additive mixture (AM) containing further additives as a masterbatch for incorporating into a base polymer of branched polypropylene.
  • the additive mixture contains 87.50 wt.-% of the linear polypropylenes 1- PP1, 10.00 wt.-% Irganox B 225 FF (antioxidant), and 2.50 wt.-% Hydrotalcit.
  • the branched polypropylene is produced (b-PP). Subsequently, via a side feeder, i.e. at the last 1/4 of the extruder length, the additive mixture is fed into the extruder to the produced branched polypropylene (b-PP)
  • the extruded polypropylene composition was discharged and pelletized. From the pellets films have been produced as described above (OCS gel index). The final properties are indicated in table 3.
  • Table 1 Set temperature profile in the extruder

Landscapes

  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Medicinal Chemistry (AREA)
  • Polymers & Plastics (AREA)
  • Organic Chemistry (AREA)
  • Health & Medical Sciences (AREA)
  • Manufacturing & Machinery (AREA)
  • Engineering & Computer Science (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Materials Engineering (AREA)
  • Compositions Of Macromolecular Compounds (AREA)
  • Processes Of Treating Macromolecular Substances (AREA)
  • Addition Polymer Or Copolymer, Post-Treatments, Or Chemical Modifications (AREA)

Abstract

Process for providing a polypropylene composition comprising a branched polypropylene in which a polypropylene with a melt flow rate MFR2 (230°C) of more than 1.0g/10min is reacted with a thermally decomposing free radical-forming agent and optionally with a bifunctionally unsaturated monomer obtaining thereby the branched polypropylene,wherein the polypropylene composition has a F30 melt strength of more than 5.8cN and a v30 melt extensibility of more than 200 mm/s.

Description

Film with low OCS gel index
The present invention relates to a method of providing a polypropylene composition having high melt strength and a low OCS gel index. Furthermore, the present invention also relates to a corresponding high melt strength (HMS) polypropylene composition with low OCS gel index.
High melt strength polypropylene (HMS-PP) compositions are generally known in the art. However, one challenge within existing HMS-PP is their varying film quality. The film quality is expressed via the gel index which is measured with the OCS gel inspection tool as described in WO 2008/022802.
Further, as known in the art, additives are normally added to plastic materials in order to improve the performance thereof. Examples of typical additives are e.g. antioxidants or pigments etc. These additives are often added to the plastic base material in the form of an additive mixture having incorporated the additives into a small amount of polymer powder. The additive mixture is sometimes also referred to as masterbatch. The small quantity of polymer powder used for the additive mixture is normally dosed at the end of the HMS process. However, the contribution to the final gel index of this additive mixture is often overlooked. Further up to now it has been not recognized that also the molecular weight of the base polymer powder in the manufacture of the high melt strength polypropylene (HMS- PP) has significant impact on the final optical properties. EP 0 879 830, filed by Borealis in 1997, describes the basics of the Borealis high melt strength (HMS) post-reactor process where peroxide and butadiene are used to make long chain branched polypropylene (LCB-PP) materials. This patent covers a wide range of powder melt flow rates (MFRs) and particle sizes. However, it does not specify the impact of the type of base polymer as well as the polypropylene powder used for the preparation of the additive mixture on the HMS quality in particular on the OCS film quality expressed via the gel index.
There remains a need in the art for a method to produce HMS-PP of reliable and/or improved quality. Accordingly the object of the present invention is to provide a process which enables a skilled person to produce a polypropylene composition and a film made of said
polypropylene composition with low gel content.
The present inventors now surprisingly found that the final gel index can be significantly reduced by increasing the MFR of the base polymer and optionally of the polypropylene powder used for the additive mixture. Thus, the present invention relates to a process for providing a polypropylene composition comprising a branched polypropylene (b-PP), like comprising at least 90 wt.-% of a branched polypropylene (b-PP), the process comprises at least a step (a) in which a polypropylene (PP) is reacted with a thermally decomposing free radical- forming agent and optionally with bifunctionally unsaturated monomer(s) and/or with multifunctionally unsaturated low molecular weight polymer(s) obtaining thereby the branched polypropylene (b-PP),
wherein
(a) the polypropylene (PP) has a melt flow rate MFR2 (230°C) of more than 1.0
g/lOmin, preferably in the range of more than 1.0 to 13.0 g/lOmin, like 3.0 to 13 g/lOmin;
(b) the polypropylene composition and/or the branched polypropylene (b-PP) has/have a F30 melt strength of more than 5.8 cN and a V30 melt extensibility of more than 200 mm/s, wherein the F30 melt strength and the V30 melt extensibility are measured according to ISO 16790:2005.
The present invention further provides a polypropylene composition comprising
(a) at least 90 parts by weight, like 95 to 99 parts by weight, of a branched
polypropylene (b-PP); and
(b) 1 to 5 parts by weight of a polypropylene (ΡΡ') having a melt flow rate MFR2
(230 °C) measured according to ISO 1133 of 1.0 to 18.0 g/lOmin,
wherein the polypropylene composition has a melt flow rate MFR2 (230 °C) measured according to ISO 1133 of 7.0 to
13.0 g/lOmin, and
a gel index of less than 1 ,000, preferably less 800;
and wherein further the polypropylene composition and/or the branched polypropylene (b- PP) has/have
a F30 melt strength of 5.8 to 13.0 cN, preferably of 6.0 to 12.5 cN, more preferably of 6.0 to 12.0 cN, and
a V30 melt extensibility of 210 to 300 mm/s,
wherein the F30 melt strength and the V30 melt extensibility are measured according to ISO 16790:2005.
In the following the invention is described in more detail.
First the individual components, i.e. the polypropylene (PP), like the linear polypropylene (1- PP'), the polypropylene (ΡΡ'), like the linear polypropylene (Ι-ΡΡ'), the branched polypropylene (b-PP), and the additives (A), used in the instant invention as well as the polypropylene composition are described. Subsequently the claimed process is described in more detail. However any information or any preferred embodiment provided for the individual components or the polypropylene composition is also applicable for the inventive process, if reference is made to the individual components and the polypropylene composition, respectively.
The branched polypropylene (b-PP) The major component for the polypropylene composition to be provided according to the invention is a branched polypropylene (b-PP). A branched polypropylene differs from a linear polypropylene that the polypropylene backbone covers side chains whereas a non- branched polypropylene, i.e. a linear polypropylene, does not cover side chains. The side chains have significant impact on the rheology of the polypropylene. Accordingly linear polypropylenes and branched polypropylenes can be clearly distinguished by its flow behavior under stress. Branching can be achieved by using specific catalysts, i.e. specific single-site catalysts, or by chemical modification. Concerning the preparation of a branched polypropylene obtained by the use of a specific catalyst reference is made to EP 1 892 264. With regard to a branched polypropylene obtained by chemical modification it is referred to EP 0 879 830 Al . In such a case the branched polypropylene is also called high melt strength polypropylene. The branched polypropylene (b-PP) according to the instant invention is obtained by chemical modification as described in more detail below and thus is a high melt strength
polypropylene (HMS-PP). Therefore the terms "branched polypropylene (b-PP)" and "high melt strength polypropylene (HMS-PP)" can be regarded in the instant invention as synonyms.
Therefore the branched polypropylene (b-PP), i.e. the high melt strength polypropylene (HMS-PP), as the major component of the polypropylene composition has a F30 melt strength of more than 5.8 cN and a V30 melt extensibility of more than 200 mm/s, preferably has a F30 melt strength of more than 5.8 to 20.0 cN and a V30 melt extensibility of more than 200 to 300 mm/s, in order to provide a resulting polypropylene composition with good shear thinning properties. The F30 melt strength and the V30 melt extensibility are measured according to ISO 16790:2005.
Typically the instant polypropylene composition also has a F30 melt strength of more than 5.8 cN and a V30 melt extensibility of more than 200 mm/s, preferably has a F30 melt strength of more than 5.8 to 20.0 cN and a V30 melt extensibility of more than 200 to 300 mm/s.
In a preferred embodiment, the branched polypropylene (b-PP), i.e. the high melt strength polypropylene (HMS-PP), has
(a) a F30 melt strength of more than 5.8 cN, like of more than 5.8 to 20.0 cN, more preferably of more than 6.0 cN, still more preferably of 6.0 to 18.0 cN, yet more preferably of 6.2 to 15.0 cN, still yet more preferably of 6.0 to 13.0 cN or of 6.2 to 13.0 cN, most preferably of 6.0 to 12.0 cN or of 6.5 to 12.0 cN, like of 6.6 to 12.0 cN or 6.6 to 11.5 cN; and
(b) a V30 melt extensibility of more than 210 to 300 mm/s, like of more than 220 to 300 mm/s, more preferably of more than 225 mm/s, still more preferably of 225 to 300 mm/s, yet more preferably of 230 to 290 mm/s.
In especially preferred embodiment the branched polypropylene (b-PP), i.e. the high melt strength polypropylene (HMS-PP), has a F30 melt strength of more than 5.8 cN and a V30 melt extensibility of more than 210 to 300 mm/s, like a F30 melt strength of more than 5.8 to 20.0 cN and V30 melt extensibility of more than 220 to 300 mm/s, more preferably a F30 melt strength of more than 6.0 cN and V30 melt extensibility of more than 225 mm/s, still more preferably a F30 melt strength of 6.0 to 18.0 cN and V30 melt extensibility of 225 to 300 mm/s, yet more preferably a F30 melt strength of 6.2 to 15.0 cN and V30 melt extensibility of 230 to 290 mm/s, still yet more preferably a F30 melt strength of 6.2 to 13.0 cN and V30 melt extensibility of 230 to 290 mm/s, most preferably a F30 melt strength of 6.0 to 12.0 cN and V30 melt extensibility of 230 to 290 mm/s, like a F30 melt strength of 6.6 to 11.5 cN and V30 melt extensibility of 230 to 290 mm/s.
Additionally or alternatively the branched polypropylene (b-PP), i.e. the high melt strength polypropylene (HMS-PP), can be further defined by the strain hardening factor (SHF). Accordingly it is preferred that the branched polypropylene (b-PP), i.e. the high melt strength polypropylene (HMS-PP), has a strain hardening factor (SHF) of at least 1.7, more preferably of at least 1.9, yet more preferably in the range of 1.9 to 7.0, still more preferably in the range of 1.9 to 6.5 measured at a strain rate of 3.0 s"1 and a Hencky strain of 2.5. Further it is preferred that said branched polypropylene (b-PP), preferably the high melt strength polypropylene (HMS-PP), has a melt flow rate MFR2 (230 °C) measured according to ISO 1133 of at least 2.0 g/lOmin, more preferably in a range of 2.0 to 40.0 g/10 min, still more preferably in a range of 4.0 to 30.0 g/10 min, yet more preferably in a range of 5.0 to 20.0 g/10 min, like in the range of 7.0 to 13.0 g/lOmin, like 8.0 to 12.0 g/lOmin. Hence in one specific embodiment, the branched polypropylene (b-PP), i.e. the high melt strength polypropylene (HMS-PP), has
(a) a melt flow rate MFR2 (230 °C) of at least 2.0 g/lOmin, preferably in a range of 2.0 to 40.0 g/10 min, more preferably in a range of 4.0 to 30.0 g/10 min, still more preferably in a range of 5.0 to 20.0 g/10 min, yet more preferably in a range of 7.0 to 13.0 g/lOmin, like in a range of 8.0 to 12.0 g/lOmin;
(b) a F30 melt strength of more than 5.8 cN, like of more than 5.8 to 20.0 cN, more preferably of more than 6.0 cN, still more preferably of 6.0 to 18.0 cN, yet more preferably of 6.2 to 15.0 cN, still yet more preferably of 6.0 to 13.0 cN or of 6.2 to 13.0 cN, most preferably of 6.0 to 12.0 cN or of 6.5 to 12.0 cN, like of 6.6 to 12.0 cN or 6.6 to 11.5 cN; and
(c) a V30 melt extensibility of more than 210 to 300 mm/s, like of more than 220 to 300 mm/s, more preferably of more than 225 mm/s, still more preferably of 225 to 300 mm/s, yet more preferably of 230 to 290 mm/s.
Accordingly in specific embodiment the branched polypropylene (b-PP), i.e. the high melt strength polypropylene (HMS-PP), has a melt flow rate MFR2 (230 °C) of at least 2.0 g/lOmin, a F30 melt strength of more than 5.8 cN and a V30 melt extensibility of more than 210 to 300 mm/s, like a melt flow rate MFR2 (230 °C) in a range of 2.0 to 40.0 g/10 min, a F30 melt strength of more than 5.8 to 20.0 cN and V30 melt extensibility of more than 220 to 300 mm/s, more preferably a melt flow rate MFR2 (230 °C) in a range of 4.0 to 30.0 g/10 min, a F30 melt strength of more than 6.0 cN and V30 melt extensibility of more than 225 mm/s, still more preferably a melt flow rate MFR2 (230 °C) in a range of 5.0 to 20.0 g/10 min, a F30 melt strength of 6.0 to 18.0 cN and V30 melt extensibility of 225 to 300 mm/s, yet more preferably a melt flow rate MFR2 (230 °C) in a range of 7.0 to 13.0 g/lOmin, a F30 melt strength of 6.2 to 15.0 cN and V30 melt extensibility of 230 to 290 mm/s, still yet more preferably a melt flow rate MFR2 (230 °C) in a range of 6.2 to 13.0 g/lOmin, a F30 melt strength of 6.2 to 13.0 cN and V30 melt extensibility of 230 to 290 mm/s, most preferably a melt flow rate MFR2 (230 °C) in a range of 8.0 to 12.0 g/lOmin, a F30 melt strength of 6.0 to 12.0 cN and v30 melt extensibility of 230 to 290 mm/s, like a melt flow rate MFR2 (230 °C) in a range of 7.0 to 13.0 g/lOmin, a F30 melt strength of 6.6 to 11.5 cN and V30 melt extensibility of 230 to 290 mm/s.
Preferably, the branched polypropylene (b-PP), i.e. the high melt strength polypropylene (HMS-PP), has a melting point of at least 130°C, more preferably of at least 135°C and most preferably of at least 140°C. The crystallization temperature is preferably at least 110 °C, more preferably at least 120 °C.
Further, the branched polypropylene (b-PP), i.e. the high melt strength polypropylene (HMS- PP), can be a branched random propylene copolymer (b-R-PP), i.e. a high melt strength random propylene copolymer (R-HMS-PP), or a branched propylene homopolymer (b-H- PP), i.e. a high melt strength propylene homopolymer (H-HMS-PP), the latter being preferred. For the purpose of the present invention, the expression "propylene homopolymer" refers to a polypropylene that consists substantially, i.e. of at least 97 mol.-%, preferably of at least 98 mol.-%, more preferably of at least 99 mol.-%, most preferably of at least 99.8 mol.-% of propylene units. In a preferred embodiment only propylene units in the propylene homopolymer are detectable.
In case the branched polypropylene (b-PP), i.e. the high melt strength polypropylene (HMS- PP), is a branched random propylene copolymer (b-R-PP), i.e. a high melt strength random propylene copolymer (R-HMS-PP), it comprises monomers copolymerizable with propylene, for example comonomers such as ethylene and/or C4 to C12 α-olefins, in particular ethylene and/or C4 to C10 a-olefins, e.g. 1-butene and/or 1-hexene. Preferably the branched random propylene copolymer (b-R-PP), i.e. the high melt strength random propylene copolymer (R- HMS-PP), comprises, especially consists of, monomers copolymerizable with propylene from the group consisting of ethylene, 1-butene and 1-hexene. More specifically the branched random propylene copolymer (b-R-PP), i.e. the high melt strength random propylene copolymer (R-HMS-PP), comprises - apart from propylene - units derivable from ethylene and/or 1-butene. In a preferred embodiment the branched random propylene copolymer (b-R-PP), i.e. the high melt strength random propylene copolymer (R-HMS-PP), comprises units derivable from ethylene and propylene only. The comonomer content in the branched random propylene copolymer (b-R-PP), i.e. in the high melt strength random propylene copolymer (R-HMS-PP), is preferably in the range of more than 0.2 to 10.0 mol.- %, still more preferably in the range of more than 0.5 to 7.0 mol.-%.
In this regard it is to mention that the high melt strength polypropylene (HMS-PP) being either a high melt strength propylene homopolymer (H-HMS-PP) or a high melt strength random propylene copolymer (R-HMS-PP) may comprise additionally unsaturated monomers different to the comonomers defined for the high melt strength random propylene copolymer (R-HMS-PP). In other words the high melt strength propylene homopolymer (H- HMS-PP) or the high melt strength random propylene copolymer (R-HMS-PP) may comprise unsaturated units, like bifunctionally unsaturated monomer(s) and/or
multifunctionally unsaturated low molecular weight polymer(s) as defined in detail below, being different to propylene, ethylene and other C4 to C12 a-olefins. Accordingly the definition of homopolymer and copolymer in view of the high melt strength polypropylene (HMS-PP) refers actually to the unmodified polypropylene, i.e. to the polypropylene (PP), preferably to the linear polypropylene (1-PP), used to obtain the melt strength polypropylene (HMS-PP) by chemical modification as defined in detail below.
Accordingly in one preferred embodiment the branched polypropylene (b-PP), i.e. the high melt strength polypropylene (HMS-PP), comprises
(a) if it is a high melt strength propylene homopolymer (H-HMS-PP) units derived from (i) propylene and
(ii) bifunctionally unsaturated monomer(s) and/or multifunctionally unsaturated low molecular weight polymer(s),
or
(b) if it is a high melt strength random propylene copolymer (R-HMS-PP) units derived from
(i) propylene (ii) ethylene and/or C4 to C10 a-olefins, e.g. 1-butene and/or 1-hexene, preferably erthylene, and
(iii) bifunctionally unsaturated monomer(s) and/or multifunctionally unsaturated low molecular weight polymer(s),
"Bifunctionally unsaturated" or "multifunctionally unsaturated" as used above means preferably the presence of two or more non-aromatic double bonds, as in e.g. divinylbenzene or cyclopentadiene or polybutadiene. Only such bi- or multifunctionally unsaturated compounds are used which can be polymerized preferably with the aid of free radicals (see below). The unsaturated sites in the bi- or multifunctionally unsaturated compounds are in their chemically bound state not actually "unsaturated", because the double bonds are each used for a covalent bond to the polymer chains of the unmodified polypropylene, i.e. of the polypropylene (PP), preferably of the linear polypropylene (1-PP). Reaction of the bifunctionally unsaturated monomer(s) and/or multifunctionally unsaturated low molecular weight polymer(s), preferably having a number average molecular weight (Mn) < 10000 g/mol, synthesized from one and/or more unsaturated monomers with the unmodified polypropylene, i.e. with the polypropylene (PP), preferably with the linear polypropylene (1-PP), are performed in the presence of a thermally free radical forming agent, e. g. decomposing free radical-forming agent, like a thermally decomposable peroxide.
The bifunctionally unsaturated monomers may be
divinyl compounds, such as divinylaniline, m-divinylbenzene, p-divinylbenzene, divinylpentane and divinylpropane;
allyl compounds, such as allyl acrylate, allyl methacrylate, allyl methyl maleate and allyl vinyl ether;
dienes, such as 1,3 -butadiene, chloroprene, cyclohexadiene, cyclopentadiene, 2,3- dimethylbutadiene, heptadiene, hexadiene, isoprene and 1 ,4-pentadiene;
- aromatic and/or aliphatic bis (maleimide) bis (citraconimide) and mixtures of these unsaturated monomers. Especially preferred bifunctionally unsaturated monomers are 1,3 -butadiene, isoprene, dimethyl butadiene and divinylbenzene. The multifunctionally unsaturated low molecular weight polymer, preferably having a number average molecular weight (Mn) < 10000 g/mol may be synthesized from one or more unsaturated monomers.
Examples of such low molecular weight polymers are
- polybutadienes, especially where the different microstructures in the polymer chain, i.e.
1 ,4-cis, 1 ,4-trans and 1 ,2-(vinyl) are predominantly in the 1 ,2-(vinyl) configuration copolymers of butadiene and styrene having 1,2- (vinyl) in the polymer chain.
A preferred low molecular weight polymer is polybutadiene, in particular a polybutadiene having more than 50.0 wt.-% of the butadiene in the l,2-(vinyl) configuration.
The branched polypropylene, i.e. the high melt strength polypropylene (HMS-PP), may contain more than one bifunctionally unsaturated monomer and/or multifunctionally unsaturated low molecular weight polymer. Even more preferred the amount of
bifunctionally unsaturated monomer(s) and multifunctionally unsaturated low molecular weight polymer(s) together in the branched polypropylene, i.e. in the high melt strength polypropylene (HMS-PP), is 0.01 to 10.0 wt.-% based on said branched polypropylene, i.e. based on said high melt strength polypropylene (HMS-PP). In a preferred embodiment the branched polypropylene (b-PP), i.e. the high melt strength polypropylene (HMS-PP), is free of additives (A). Accordingly in case the instant polypropylene composition comprises additives (A), these additives (A) are not brought in the polypropylene composition during the manufacture of the branched polypropylene (b- PP), i.e. of the high melt strength polypropylene (HMS-PP). The polypropylene (PP)
As mentioned above, the branched polypropylene (b-PP), i.e. the high melt strength polypropylene (HMS-PP), is a modified polypropylene, which is obtained by reacting the polypropylene (PP) with a thermally decomposing free radical-forming agent and optionally with bifunctionally unsaturated monomer(s) and/or with multifunctionally unsaturated low molecular weight polymer(s).
Essential aspect of the invention is that a specific unmodified polypropylene must be used in the present invention for the manufacture of the branched polypropylene (b-PP), i.e. of the high melt strength polypropylene (HMS-PP), and thus for the manufacture of the polypropylene composition comprising the branched polypropylene (b-PP), i.e. comprising the high melt strength polypropylene (HMS-PP). A particular finding is that the
polypropylene (PP), preferably the linear polypropylene (1-PP), must have a rather low molecular weight and thus a rather high melt flow rate. Accordingly it is preferred that the polypropylene (PP), preferably the linear polypropylene (1-PP), has a melt flow rate MFR2 (230°C) measured according to ISO 1133 of more than 1.0 g/lOmin, preferably in the range of more than 1.0 to 18.0 g/lOmin, like of more than 1.0 to 15.0 g/lOmin or of more than 1.1 to 15.0 g/lOmin, more preferably of more than 1.2 to 15.0 g/lOmin or of 1.5 to 15.0 g/lOmin, still more preferably of 2.0 to 15.0 g/lOmin, yet more preferably of 3.0 to 13.0 g/lOmin.
In one specific example the polypropylene (PP), preferably the linear polypropylene (1-PP), has a melt flow rate MFR2 (230°C) measured according to ISO 1133 of more than 1.0 g/lOmin, preferably in the range of more than 1.0 to 18.0 g/lOmin, like of more than 1.0 to 15.0 g/lOmin or of more than 1.1 to 15.0 g/lOmin, more preferably of more than 1.2 to 15.0 g/lOmin or of 1.5 to 15.0 g/lOmin, still more preferably of 2.0 to 15.0 g/lOmin, yet more preferably of 3.0 to 13.0 g/lOmin, with the proviso that the value of 10.0 g/lOmin is excluded. The branched polypropylene (b-PP), i.e. the high melt strength polypropylene (HMS-PP), differs from the polypropylene (PP) which is used for its manufacture that the backbone of the branched polypropylene (b-PP), i.e. of the high melt strength polypropylene (HMS-PP), covers side chains whereas the staring product, i.e. the polypropylene (PP), does not cover or nearby does not cover side chains. The side chains have significant impact on the rheology of the polypropylene. Accordingly staring product, i.e. the polypropylene (PP), and the obtained branched polypropylene (b-PP), i.e. the high melt strength polypropylene (HMS- PP), can be clearly distinguished by its flow behavior under stress.
Further, as mentioned above the polypropylene (PP) is preferably a linear polypropylene (1- PP). The same considerations apply to the polypropylene (ΡΡ') as discussed in detail below which is also in a preferred embodiment a linear polypropylene (Ι-ΡΡ'). Accordingly, throughout the instant invention, the term "linear polypropylene" indicates that the linear polypropylene, shows no or nearby no-branching structure. Due to the absence of branches, the linear polypropylenes, i.e. the linear polypropylene (1-PP) and the linear polypropylene (Ι-ΡΡ'), are preferably featured by a low V30 melt extensibility and/or a low F30 melt strength.
Thus it is preferred that the linear polypropylene (1-PP) has
(a) a F30 melt strength of more than 1.0 cN, preferably of more than 2.0 cN, more
preferably in the range of 1.0 to 65 cN, still more preferably in the range of 1.5 to 50 cN, yet more preferably in the range of 2.0 to 50 cN, stillyet more preferably in the range of 2.5 to 50 cN like in the range of 2.5 to 30 cN;
and
(b) a V30 melt extensibility of below 200 mm/s, preferably of below 190 mm/s, more preferably in the range of 100 to below 200 mm/s, still more preferably in the range of 120 to 190 mm/s, yet more preferably in the range of 120 to 175 mm/s, like in the range of 125 to 170 mm/s.
In other words it is preferred that the linear polypropylene (1-PP) has a F30 melt strength of more than 1.0 cN and a V30 melt extensibility of below 200 mm/s, preferably a F30 melt strength of more than 2.0 cN and a V30 melt extensibility of below 190 mm/s, more preferably a F30 melt strength in the range of 1.0 to 65 cN and a V30 melt extensibility in the range of 100 to below 200 mm/s, yet more preferably a F30 melt strength in the range of 2.0 to 50 cN and in the range of 120 to 190 mm/s, still yet more preferably a F30 melt strength in the range of 2.5 to 50 cN and in the range of 120 to 190 mm/s, like a F30 melt strength in the range of 2.5 to 30 cN and a V30 melt extensibility in the range of 120 to 175 mm/s.
Accordingly in one specific embodiment the linear polypropylene (1-PP) has
(a) a melt flow rate MFR2 (230 °C) measured according to ISO 1133 of more than 1.0 g/lOmin, preferably in the range of more than 1.0 to 18.0 g/lOmin, like of more 1.0 to 15.0 g/1 Omin, more preferably of 1.5 to 15.0 g/1 Omin, still more preferably of 2.0 to 15.0 g/lOmin, yet more preferably of 3.0 to 13.0 g/lOmin;
(b) a F30 melt strength of more than 1.0 cN, preferably of more than 2.0 cN, more
preferably in the range of 1.0 to 65 cN, still more preferably in the range of 1.5 to 50 cN, yet more preferably in the range of 2.0 to 50 cN, stillyet more preferably in the range of 2.5 to 50 cN like in the range of 2.5 to 30 cN; and
(c) a V30 melt extensibility of below 200 mm/s, preferably of below 190 mm/s, more preferably in the range of 100 to below 200 mm/s, still more preferably in the range of 120 to 190 mm/s, yet more preferably in the range of 120 to 175 mm/s, like in the range of 125 to 170 mm/s.
Therefore, in one specific embodiment the polypropylene (PP) is a linear polypropylene (1- PP) having a melt flow rate MFR2 (230 °C) of more than 1.0 g/1 Omin, a F30 melt strength of more than 1.0 cN and a V30 melt extensibility of below 200 mm/s, preferably a melt flow rate MFPv2 (230 °C) in the range of more than 1.0 to 18.0 g/1 Omin, a F30 melt strength of more than 2.0 cN and a V30 melt extensibility of below 190 mm/s, more preferably a melt flow rate MFPv2 (230 °C) in the range of more 1.0 to 15.0 g/1 Omin, a F30 melt strength in the range of 1.0 to 65 cN and a V30 melt extensibility in the range of 100 to below 200 mm/s, yet more preferably a melt flow rate MFR2 (230 °C) in the range of more 1.5 to 15.0 g/1 Omin a F30 melt strength in the range of 2.0 to 50 cN and in the range of 120 to 190 mm/s, still yet more preferably a melt flow rate MFR2 (230 °C) in the range of more 2.0 to 15.0 g/1 Omin, a F30 melt strength in the range of 2.5 to 50 cN and in the range of 120 to 190 mm/s, like a melt flow rate MFR2 (230 °C) in the range of more 3.0 to 13.0 g/lOmin a F30 melt strength in the range of 2.5 to 30 cN and a V30 melt extensibility in the range of 120 to 175 mm/s. Preferably, the polypropylene (PP), preferably the linear polypropylene (1-PP), has a melting point of at least 140°C, more preferably of at least 150°C and still more preferably of at least 158°C.
Additionally it is preferred that the polypropylene (PP), preferably the linear polypropylene (1-PP), is used in form of particles of specific size. Accordingly it is preferred that the polypropylene (PP), preferably the linear polypropylene (1-PP), has
(a) a particle size distribution dgo of below 1,500 μιη; more preferably below 1,000 μιη, still more preferably in the range of 50 to below 1,000 μιη, yet more preferably in the range of 100 to 800 μιη, like in the range of 150 to 600 μιη;
and/or
(b) a particle size distribution d5o of below 1,000 μιη; more preferably below 800 μιη, still more preferably in the range of 30 to below 1,000 μιη, yet more preferably in the range of 50 to 600 μιη, like in the range of 100 to 500 μιη;
and/or
(c) a d9o/d5o ratio of below 1.80, more preferably below 1.75, still more preferably below 1.50, yet more preferably in the range of 1.00 to 1.75, still yet more preferably in the range of 1.10 to 1.50.
The polypropylene (PP), preferably the linear polypropylene (1-PP), can be produced in a known manner for instance by employing a single-site or a Ziegler Natta catalyst. The polypropylene (PP), preferably the linear polypropylene (1-PP), can be a propylene homopolymer (H-PP), preferably a linear propylene homopolymer (1-H-PP), or a propylene copolymer (R-PP), preferably a linear propylene copolymer (1-R-PP). Concerning the comonomer content and type of comonomer it is referred to the information provided above for the branched polypropylene (b-PP), especially it is referred to the high melt strength random propylene copolymer (R-HMS-PP). Preferably the polypropylene (PP) is a linear polypropylene (1-PP). Still more preferably the polypropylene (PP) is a linear propylene homopolymer (1-H-PP). Accordingly all information provided with regard to melt flow rate MFR2 (230°C), melting point, F30 melt strength, V30 melt extensibility, and particle size and particle size distribution, respectively, applies especially for the linear propylene homopolymer (1-H-PP).
In a preferred embodiment the polypropylene (PP), preferably the linear polypropylene (1- PP), is free of additives (A). Accordingly in case the instant polypropylene composition comprises additives (A), these additives (A) are not brought in the polypropylene composition during the manufacture of the branched polypropylene (b-PP), i.e. of the high melt strength polypropylene (HMS-PP). The polypropylene (ΡΡ')
During the preparation of the instant polypropylene composition a further polypropylene (ΡΡ') may be added. This polypropylene (ΡΡ') is preferably used to bring additives (A) in the instant polypropylene composition. It is a further finding of the present invention that especially good results in view of optical properties, i.e. in terms of low gel index, are achieved for the instant polypropylene composition if the additives (A) are brought in by use of a specific polypropylene carrier. Accordingly in a preferred embodiment the additives (A) are introduced in the instant polypropylene composition in the form of an additive mixture (AM), wherein said additive mixture comprises, preferably consists of, the polypropylene (ΡΡ') and the additives (A).
Preferably the polypropylene (PP')> is a linear polypropylene (Ι-ΡΡ').
More preferably the polypropylene (PP')> i-e. the linear polypropylene (ΡΡ'), must have a rather low molecular weight and thus a rather high melt flow rate. Accordingly it is preferred that the polypropylene (ΡΡ'), preferably the linear polypropylene (Ι-ΡΡ'), has a melt flow rate MFPv2 (230°C) measured according to ISO 1133 of more than 1.0 g/lOmin, preferably in the range of more than 1.0 to 18.0 g/lOmin, like of more 1.0 to 15.0 g/lOmin, more preferably of 1.5 to 15.0 g/lOmin, still more preferably of 2.0 to 15.0 g/lOmin, yet more preferably of 3.0 to 13.0 g/10min. Preferably, the polypropylene (PP')> preferably the linear polypropylene (Ι-ΡΡ'), has a melting point of at least 140°C, more preferably of at least 150°C and still more preferably of at least 158°C. Further, as mentioned above the polypropylene (ΡΡ') is preferably a linear polypropylene (1- PP') and thus shows no or nearby no-branching structure. Due to the absence of branches the linear polypropylene (Ι-ΡΡ') is preferably featured by a low V30 melt extensibility and/or a low F30 melt strength. Thus it is preferred that the linear polypropylene (Ι-ΡΡ') has
(a) a F30 melt strength of more than 1.0 cN, preferably of more than 2.0 cN, more
preferably in the range of 1.0 to 65 cN, still more preferably in the range of 1.5 to 50 cN, yet more preferably in the range of 2.0 to 50 cN, still yet more preferably in the range of 2.5 to 50 cN like in the range of 2.5 to 30 cN;
and
(b) a V30 melt extensibility of below 200 mm/s, preferably of below 190 mm/s, more preferably in the range of 100 to below 200 mm/s, still more preferably in the range of 120 to 190 mm/s, yet more preferably in the range of 120 to 175 mm/s, like in the range of 125 to 170 mm/s.
In other words it is preferred that the linear polypropylene (Ι-ΡΡ') has a F30 melt strength of more than 1.0 cN and a V30 melt extensibility of below 200 mm/s, preferably a F30 melt strength of more than 2.0 cN and a V30 melt extensibility of below 190 mm/s, more preferably a F30 melt strength in the range of 1.0 to 65 cN and a V30 melt extensibility in the range of 100 to below 200 mm/s, yet more preferably a F30 melt strength in the range of 2.0 to 50 cN and in the range of 120 to 190 mm/s, still yet more preferably a F30 melt strength in the range of 2.5 to 50 cN and in the range of 120 to 190 mm/s, like a F30 melt strength in the range of 2.5 to 30 cN and a V30 melt extensibility in the range of 120 to 175 mm/s.
Accordingly in one specific embodiment the linear polypropylene (Ι-ΡΡ') has a melt flow rate MFR2 (230 °C) measured according to ISO 1133 of more than 1.0 g/lOmin, preferably in the range of more than 1.0 to 18.0 g/lOmin, like of more 1.0 to 15.0 g/1 Omin, more preferably of 1.5 to 15.0 g/1 Omin, still more preferably of 2.0 to 15.0 g/lOmin, yet more preferably of 3.0 to 13.0 g/lOmin;
a F30 melt strength of more than 1.0 cN, preferably of more than 2.0 cN, more preferably in the range of 1.0 to 65 cN, still more preferably in the range of 1.5 to 50 cN, yet more preferably in the range of 2.0 to 50 cN, still yet more preferably in the range of 2.5 to 50 cN like in the range of 2.5 to 30 cN; and
a V30 melt extensibility of below 200 mm/s, preferably of below 190 mm/s, more preferably in the range of 100 to below 200 mm/s, still more preferably in the range of 120 to 190 mm/s, yet more preferably in the range of 120 to 175 mm/s, like in the range of 125 to 170 mm/s.
Therefore, in one specific embodiment the polypropylene (ΡΡ') is a linear polypropylene (1- PP') having a melt flow rate MFR2 (230 °C) of more than 1.0 g/1 Omin, a F30 melt strength of more than 1.0 cN and a V30 melt extensibility of below 200 mm/s, preferably a melt flow rate MFPv2 (230 °C) in the range of more than 1.0 to 18.0 g/1 Omin, a F30 melt strength of more than 2.0 cN and a V30 melt extensibility of below 190 mm/s, more preferably a melt flow rate MFPv2 (230 °C) in the range of more 1.0 to 15.0 g/1 Omin, a F30 melt strength in the range of 1.0 to 65 cN and a V30 melt extensibility in the range of 100 to below 200 mm/s, yet more preferably a melt flow rate MFR2 (230 °C) in the range of more 1.5 to 15.0 g/lOmin a F30 melt strength in the range of 2.0 to 50 cN and in the range of 120 to 190 mm/s, still yet more preferably a melt flow rate MFR2 (230 °C) in the range of more 2.0 to 15.0 g/1 Omin, a F30 melt strength in the range of 2.5 to 50 cN and in the range of 120 to 190 mm/s, like a melt flow rate MFR2 (230 °C) in the range of more 3.0 to 13.0 g/lOmin a F30 melt strength in the range of 2.5 to 30 cN and a V30 melt extensibility in the range of 120 to 175 mm/s.
Additionally it is preferred that the polypropylene (PP')> preferably the linear polypropylene (Ι-ΡΡ'), is used in form of particles of specific size. Accordingly it is preferred that the polypropylene (PP')> preferably the linear polypropylene (Ι-ΡΡ'), has (a) a particle size distribution dw of below 1,500 μηι; more preferably below 1,000 μιη, still more preferably in the range of 50 to below 1,000 μιη, yet more preferably in the range of 100 to 800 μιη, like in the range of 150 to 600 μιη;
and/or
(b) a particle size distribution d5o of below 1,000 μιη; more preferably below 800 μιη, still more preferably in the range of 30 to below 1,000 μιη, yet more preferably in the range of 50 to 600 μιη, like in the range of 100 to 500 μιη;
and/or
(c) a d9o/d5o ratio of below 1.80, more preferably below 1.75, still more preferably below 1.50, yet more preferably in the range of 1.00 to 1.75, still yet more preferably in the range of 1.10 to 1.50.
The polypropylene (PP')> preferably the linear polypropylene (Ι-ΡΡ'), can be produced in a known manner for instance by employing a single-site or a Ziegler Natta catalyst. The polypropylene (ΡΡ'), preferably the linear polypropylene (Ι-ΡΡ'), can be a propylene homopolymer (Η-ΡΡ'), preferably a linear propylene homopolymer (Ι-Η-ΡΡ'), or a propylene copolymer (R-PP'), preferably a linear propylene copolymer (1-R-PP'). Concerning the comonomer content and type of comonomer it is referred to the information provided above for the branched polypropylene (b-PP) especially it is referred to the high melt strength random propylene copolymer (R-HMS-PP). Preferably the polypropylene (ΡΡ') is a linear polypropylene (Ι-ΡΡ'). Still more preferably the polypropylene (ΡΡ') is a linear propylene homopolymer (Ι-Η-ΡΡ'). Accordingly all information provided with regard to melt flow rate MFR2 (230°C), melting point, F30 melt strength, V30 melt extensibility, and particle size and particle size distribution, respectively, applies especially for the linear propylene homopolymer (Ι-Η-ΡΡ').
In a specific embodiment the polypropylene (PP) and the polypropylene (ΡΡ') are the same. Accordingly in one preferred embodiment the polypropylene (PP) and the polypropylene (ΡΡ') are linear propylene homopolymers, i.e. a linear propylene homopolymer (1-H-PP) and a linear propylene homopolymer (Ι-Η-ΡΡ'), with the same properties, in particular in view of melt flow rate MFR2 (230 °C), F30 melt strength and V30 melt extensibility as discussed above.
As mentioned above the polypropylene (ΡΡ') is used as a carrier to introduce the additives (A) in the polypropylene composition. In other words an additive mixture (AM) comprising, preferably consisting of, the polypropylene (ΡΡ') and the additives (A) is used in the instant process for the manufacture of the polypropylene composition.
The additives (A) can be any additives useful in the technical area of the high melt strength polypropylene (HMS-PP) and its applications. Accordingly the additives (A) to be used in the polypropylene composition of the invention and thus in form of the additive mixture (AM) include, but are not limited to, stabilizers such as antioxidants (e.g. sterically hindered phenols, phosphites/phosphonites, sulphur containing antioxidants, alkyl radikal scavangers, aromatic amines, hindered amine stabilizers, or blends thereof), metal deactivators (e.g. Irganox MD 1024), or UV stabilizers (e.g. hindered amine light stabilizers). Other typical additives are modifiers such as antistatic or antifogging agents (e.g. ethoxylated amines and amides, or glycerol esters), acid scavengers (e.g. Ca-stearate), blowing agents, cling agents (e.g. polyisobutene), lubriciants and resins (ionomer waxes, PE- and ethylene copolymer waxes, Fischer-Tropsch waxes, Montan-based waxes, Fluoro-based compounds, or paraffin waxes), nucleating agents (e.g. talc, benzoates, phosphorous-based compounds, sorbitoles, nonitol-based compounds, or amide-based compounds), as well as slip and antiblocking agents (e.g. erucamide, oleamide, talc natural silica and synthetic silica, or zeolites).
Preferably the additives (A) are selected from the group consisting of antioxidants (e.g. sterically hindered phenols, phosphites/phosphonites, sulphur containing antioxidants, alkyl radikyl scavangers, aromatic amines, hindered amine stabilizers, or blends thereof), metal deactivators (e.g. Irganox MD 1024), or UV stabilizers (e.g. hindered amine light stabilizers), antistatic or antifogging agents (e.g. ethoxylated amines and amides, or glycerol esters), acid scavengers (e.g. Ca-stearate), blowing agents, cling agents (e.g. polyisobutene), lubriciants and resins (ionomer waxes, PE- and ethylene copolymer waxes, Fischer-Tropsch waxes, Montan-based waxes, Fluoro-based compounds, or paraffin waxes), nucleating agents (e.g. talc, benzoates, phosphorous-based compounds, sorbitoles, nonitol-based compounds, or amide-based compounds), slip agents, antiblocking agents (e.g. erucamide, oleamide, talc natural silica and synthetic silica, or zeolites) and mixtures thereof.
Typically the total amount of additives (A) in the additive mixture (AM) is not more than 25 wt.-%, more preferably not more than 20 wt.-%, like in the range of 5 to 20 wt.-% based on the total weight of the additive mixture (AM).
The polypropylene composition As mentioned above due to the instant process a polypropylene composition is obtained which comprises a branched polypropylene (b-PP), i.e. a high melt strength polypropylene (HMS-PP). In a preferred embodiment the instant polypropylene composition comprises a branched polypropylene (b-PP), i.e. a high melt strength polypropylene (HMS-PP), a polypropylene (PP')> preferably a linear polypropylene (Ι-ΡΡ'), and optionally at least one additive (A).
The major component in the instant polypropylene composition is the branched
polypropylene (b-PP), i.e. the high melt strength polypropylene (HMS-PP). Accordingly the polypropylene composition comprises at least 70 wt.-%, more preferably at least 75 wt.-%, yet more preferably at least 80 wt.-%, still more preferably at least 85 wt.-%, still yet more preferably at least 90 wt.-%, like at least 95 wt.-%, of the branched polypropylene (b-PP), i.e. the high melt strength polypropylene (HMS-PP).
More preferably the instant polypropylene composition comprises
(a) 80 to 99 parts by weight, preferably 90 to 99 parts by weight, more preferably 95 to 99 parts by weight, of the branched polypropylene (b-PP), preferably of the high melt strength polypropylene (HMS-PP); and
(b) 1 to 20 parts by weight, preferably 1 to 10 parts by weight, more preferably 1 to 5 parts by weight, of polypropylene (PP')> preferably of the linear polypropylene (1- PP'). In a preferred embodiment the branched polypropylene (b-PP), i.e. the high melt strength polypropylene (HMS-PP), and the polypropylene (ΡΡ'), preferably the linear polypropylene (Ι-ΡΡ'), are the only polymer components in the polypropylene composition. In other words the polypropylene composition may comprise further at least one additive (A) as defined in more detail above but no other polymers in an amount exceeding 5 wt.-%, more preferably exceeding 2 wt.-%, still more preferably exceeding 1 wt.-%, based on the total weight of the polypropylene composition. In a specific embodiment polypropylene composition consists of the branched polypropylene (b-PP), i.e. the high melt strength polypropylene (HMS-PP), the polypropylene (ΡΡ'), preferably the linear polypropylene (Ι-ΡΡ'), and at least one additive (A).
Preferably the total amount of additives (A) in the polypropylene composition is not more 5.0 wt.-%, more preferably not more than 1.0 wt.-%, like in the range of 0.005 to 0.5 wt.-%, based on the total weight of the polypropylene composition.
Therefore the present process is directed to the manufacture of a polypropylene composition comprising
(a) 80 to 99 parts by weight, preferably 90 to 99 parts by weight, more preferably 95 to 99 parts by weight, of the branched polypropylene (b-PP), i.e. of the high melt strength polypropylene (HMS-PP);
(b) 1 to 20 parts by weight, preferably 1 to 10 parts by weight, more preferably 1 to 5 parts by weight, of polypropylene (PP')> preferably of the linear polypropylene (1- PP'), having a melt flow rate MFR2 (230 °C) measured according to ISO 1133 of 1.0 to 18.0 g/lOmin, preferably of 1.0 to 15.0 g/lOmin, more preferably of 1.5 to 15.0 g/lOmin, yet more preferably of 2.0 to 15.0 g/lOmin, like of 3.0 to 13.0; and
(c) optionally 0.005 to 5.0, preferably 0.005 to 2.0, more preferably 0.05 to 1.0, like 0.05 to 0.5, parts by weight of additives (A), wherein said additives(A) are preferably selected from the group consisting of antioxidants, metal deactivators, UV-stabilizers, antistatic agents, antifogging agents, acid scavengers, blowing agents, cling agents, lubricants, nucleating agents, slip agents, antiblocking agents and mixtures thereof. As mentioned above the branched polypropylene (b-PP), i.e the high melt strength polypropylene (HMS-PP), is the dominant part in the instant polypropylene composition. Accordingly it is preferred that the final polypropylene composition shows a similar rheology behavior as the branched polypropylene (b-PP), i.e. the high melt strength polypropylene (HMS-PP).
Thus the instant polypropylene composition has
(a) a F30 melt strength of more than 5.8 cN, like of more than 5.8 to 20.0 cN, more preferably of more than 6.0 cN, still more preferably of 6.0 to 18.0 cN, yet more preferably of 6.2 to 15.0 cN, still yet more preferably of 6.0 to 13.0 cN or of 6.2 to 13.0 cN, most preferably of 6.0 to 12.0 cN or of 6.5 to 12.0 cN, like of 6.6 to 12.0 cN or 6.6 to 11.5 cN;
and
(b) a V30 melt extensibility of more than 210 to 300 mm/s, like of more than 220 to 300 mm/s, more preferably of more than 225 mm/s, still more preferably of 225 to 300 mm/s, yet more preferably of 230 to 290 mm/s.
In especially preferred embodiment the instant polypropylene composition has a F30 melt strength of more than 5.8 cN and a V30 melt extensibility of more than 210 to 300 mm/s, like a F30 melt strength of more than 5.8 to 20.0 cN and V30 melt extensibility of more than 220 to 300 mm/s, more preferably a F30 melt strength of more than 6.0 cN and V30 melt extensibility of more than 225 mm/s, still more preferably a F30 melt strength of 6.0 to 18.0 cN and V30 melt extensibility of 225 to 300 mm/s, yet more preferably a F30 melt strength of 6.2 to 15.0 cN and V30 melt extensibility of 230 to 290 mm/s, still yet more preferably a F30 melt strength of 6.2 to 13.0 cN and V30 melt extensibility of 230 to 290 mm/s, most preferably a F30 melt strength of 6.0 to 12.0 cN and V30 melt extensibility of 230 to 290 mm/s, like a F30 melt strength of 6.6 to 11.5 cN and V30 melt extensibility of 230 to 290 mm/s. Additionally or alternatively the instant polypropylene composition can be further defined by the strain hardening factor (SHF). Accordingly it is preferred that the instant polypropylene composition has a strain hardening factor (SHF) of at least 1.7, more preferably of at least 1.9, yet more preferably in the range of 1.9 to 7.0, still more preferably in the range of 1.9 to 6.5 measured at a strain rate of 3.0 s"1 and a Hencky strain of 2.5. Further it is preferred that the instant polypropylene composition has a melt flow rate MFR2 (230 °C) measured according to ISO 1133 of at least 2.0 g/lOmin, more preferably in a range of 2.0 to 40.0 g/10 min, still more preferably in a range of 4.0 to 30.0 g/10 min, yet more preferably in a range of 5.0 to 20.0 g/10 min, like in the range of 7.0 to 13.0 g/lOmin, like 8.0 to 12.0 g/lOmin.
Hence in one specific embodiment, the instant polypropylene composition has
(a) a melt flow rate MFR2 (230 °C) of at least 2.0 g/lOmin, preferably in a range of 2.0 to 40.0 g/10 min, more preferably in a range of 4.0 to 30.0 g/10 min, still more preferably in a range of 5.0 to 20.0 g/10 min, yet more preferably in a range of 7.0 to 13.0 g/lOmin, like in a range of 8.0 to 12.0 g/lOmin;
(b) a F30 melt strength of more than 5.8 cN, like of more than 5.8 to 20.0 cN, more preferably of more than 6.0 cN, still more preferably of 6.0 to 18.0 cN, yet more preferably of 6.2 to 15.0 cN, still yet more preferably of 6.0 to 13.0 cN or of 6.2 to 13.0 cN, most preferably of 6.0 to 12.0 cN or of 6.5 to 12.0 cN, like of 6.6 to 12.0 cN or 6.6 to 11.5 cN; and
(c) a V30 melt extensibility of more than 210 to 300 mm/s, like of more than 220 to 300 mm/s, more preferably of more than 225 mm/s, still more preferably of 225 to 300 mm/s, yet more preferably of 230 to 290 mm/s. Accordingly in a more specific embodiment the instant polypropylene composition has a melt flow rate MFR2 (230 °C) of at least 2.0 g/lOmin, a F30 melt strength of more than 5.8 cN and a V30 melt extensibility of more than 210 to 300 mm/s, like a melt flow rate MFR2 (230 °C) in a range of 2.0 to 40.0 g/10 min, a F30 melt strength of more than 5.8 to 20.0 cN and V30 melt extensibility of more than 220 to 300 mm/s, more preferably a melt flow rate MFR2 (230 °C) in a range of 4.0 to 30.0 g/10 min, a F30 melt strength of more than 6.0 cN and V30 melt extensibility of more than 225 mm/s, still more preferably a melt flow rate MFR2 (230 °C) in a range of 5.0 to 20.0 g/10 min, a F30 melt strength of 6.0 to 18.0 cN and V30 melt extensibility of 225 to 300 mm/s, yet more preferably a melt flow rate MFR2 (230 °C) in a range of 7.0 to 13.0 g/lOmin, a F30 melt strength of 6.2 to 15.0 cN and V30 melt extensibility of 230 to 290 mm/s, still yet more preferably a melt flow rate MFR2 (230 °C) in a range of 6.2 to 13.0 g/lOmin, a F30 melt strength of 6.2 to 13.0 cN and V30 melt extensibility of 230 to 290 mm/s, most preferably a melt flow rate MFR2 (230 °C) in a range of 8.0 to 12.0 g/lOmin, a F30 melt strength of 6.0 to 12.0 cN and V30 melt extensibility of 230 to 290 mm/s, like a melt flow rate MFR2 (230 °C) in a range of 7.0 to 13.0 g/lOmin, a F30 melt strength of 6.6 to 11.5 cN and V30 melt extensibility of 230 to 290 mm/s.
Essential finding of the present invention is that the instant polypropylene composition and thus films made from said polypropylene composition (especially as defined below) show a reduced OCS gel index. Accordingly it is preferred that the instant polypropylene composition has OCS gel index of less than 1,000, preferably of less than 800, more preferably less than 500, still more preferably in the range of 5 to 800, yet more preferably in the range of 10 to 300, still yet more preferably in the range of 10 to 200.
Keeping the information provide above in mind the present invention for instance covers a polypropylene composition comprising
(a) 80 to 99 parts by weight, preferably 90 to 99 parts by weight, more preferably 95 to 99 parts by weight, of the branched polypropylene (b-PP), i.e. of the high melt strength polypropylene (HMS-PP);
(b) 1 to 20 parts by weight, preferably 1 to 10 parts by weight, more preferably 1 to 5 parts by weight, of polypropylene (PP')> preferably of the linear polypropylene (1- PP'), having a melt flow rate MFR2 (230 °C) measured according to ISO 1133 of 1.0 to 18.0 g/lOmin, preferably of 1.0 to 15.0 g/lOmin, more preferably of 1.5 to 15.0 g/lOmin, yet more preferably of 2.0 to 15.0 g/lOmin, like of 3.0 to 13.0; and
(c) optionally 0.005 to 5.0, preferably 0.005 to 2.0, more preferably 0.05 to 1.0, like 0.05 to 0.5, parts by weight of additives (A), wherein said additives(A) are preferably selected from the group consisting of antioxidants, metal deactivators, UV-stabilizers, antistatic agents, antifogging agents, acid scavengers, blowing agents, cling agents, lubricants, nucleating agents, slip agents, antiblocking agents and mixtures thereof;
wherein the polypropylene composition has
a melt flow rate MFR2 (230 °C) of at least 2.0 g/lOmin, preferably in a range of 2.0 to 40.0 g/10 min, more preferably in a range of 4.0 to 30.0 g/10 min, still more preferably in a range of 5.0 to 20.0 g/10 min, yet more preferably in a range of 7.0 to 13.0 g/lOmin, like in a range of 8.0 to 12.0 g/lOmin; and
a OCS gel index of less than 1,000, preferably of less than 800, more preferably less than 500, still more preferably in the range of 5 to 800, yet more preferably in the range of 10 to 300, still yet more preferably in the range of 10 to 200;
and wherein the polypropylene composition and/or the branched polypropylene (b-PP), i.e. the high melt strength polypropylene (HMS-PP), has/have
a F30 melt strength of more than 5.8 cN, like of more than 5.8 to 20.0 cN, more preferably of more than 6.0 cN, still more preferably of 6.0 to 18.0 cN, yet more preferably of 6.2 to 15.0 cN, still yet more preferably of 6.0 to 13.0 cN or of 6.2 to 13.0 cN, most preferably of 6.0 to 12.0 cN or of 6.5 to 12.0 cN, like of 6.6 to 12.0 cN or 6.6 to 11.5 cN; and
a V30 melt extensibility of more than 210 to 300 mm/s, like of more than 220 to 300 mm/s, more preferably of more than 225 mm/s, still more preferably of 225 to 300 mm/s, yet more preferably of 230 to 290 mm/s.
The film
As mentioned above, the present invention also features a film comprising the instant polypropylene composition described herein. Preferably the film is a cast film or a blown film. The film may also be a biaxially oriented film, like biaxially oriented blown film. The differences between such films are known to the skilled person. Reference is made in this regard to the "Polypropylene Handbook", pages 405 to 414, 2nd Edition, Nello Pasquini (Ed.), Hanser. Preferably the film comprises at least 70 wt.-%, more preferably at least 80 wt.-%, more preferably at least 90 wt.-%, yet more preferably at least 95 wt.-%, of the polypropylene composition according to the instant invention. In a preferred embodiment the film consists of the instant polypropylene composition.
The Process
One essential aspect of the present invention is that the manufacture of the polypropylene composition comprising the branched polypropylene (b-PP), i.e. comprising the high melt strength polypropylene (HMS-PP), by using the polypropylene (PP), preferably the linear polypropylene (1-PP). In other words, the present invention relates to a process for providing a polypropylene composition comprising the branched polypropylene (b-PP), wherein the process comprises at least a step (a) in which a polypropylene (PP) is reacted with a thermally decomposing free radical-forming agent and optionally with biiunctionally unsaturated monomer(s) and/or with multifunctionally unsaturated low molecular weight polymer(s) obtaining thereby the branched polypropylene (b-PP). Preferably the instant process comprises subsequent to step (a) a further step (b), in which to the branched polypropylene (b-PP), i.e. to the high melt strength polypropylene (HMS-PP), the polypropylene (ΡΡ') is added. Even more preferred the instant process comprises subsequent to step (a) a further step (b), in which to the branched polypropylene (b-PP), i.e. to the high melt strength polypropylene (HMS-PP), the additive mixture (AM) comprising the polypropylene (ΡΡ') and the additives (A) is added. Concerning the definitions and preferred embodiments of the polypropylene composition, the branched polypropylene (b-PP), the polypropylene (PP), the polypropylene (ΡΡ'), the additives (A) and the additive mixture (AM) reference is made to the information provide above. As mentioned above, in step (a) the branched polypropylene (b-PP), i.e. the high melt strength polypropylene (HMS-PP), is obtained by treating the polypropylene (PP), preferably the linear polypropylene (1-PP), with thermally decomposing radical-forming agents.
However in such high risk exists that the polypropylene (PP), preferably the linear polypropylene (PP), is degraded, which is detrimental. Thus it is preferred that the chemical modification is accomplished by the additional use of bifunctionally unsaturated monomer(s) and/or multifunctionally unsaturated low molecular weight polymer(s) as chemically bound bridging unit(s). A suitable method to obtain the branched polypropylene (b-PP), i.e. the high melt strength polypropylene (HMS-PP), is for instance disclosed in EP 0 787 750,
EP 0 879 830 Al and EP 0 890 612 A2. All documents are herewith included by reference. Thereby, the amount of thermally decomposing radical-forming agents, preferably of peroxide, is preferably in the range of 0.05 to 3.00 wt.-% based on the amount of the polypropylene (PP). Typically the thermally decomposing radical-forming agents are added together with the bifunctionally unsaturated monomer(s) and/or with multifunctionally unsaturated low molecular weight polymer(s) to the polypropylene (PP), preferably to the linear polypropylene (1-PP). However it is also possible, but less preferred, that
first the bifunctionally unsaturated monomer(s) and/or multifunctionally unsaturated low molecular weight polymer(s) is/are added to the polypropylene (PP), preferably to the linear polypropylene (1-PP), and subsequent the thermally decomposing radical- forming agents, or the other way round,
first the thermally decomposing radical-forming agents are added to the polypropylene (PP), preferably to the linear polypropylene (1-PP), and subsequent the bifunctionally unsaturated monomer(s) and/or multifunctionally unsaturated low molecular weight polymer(s).
Concerning the bifunctionally unsaturated monomer(s) and/or multifunctionally unsaturated low molecular weight polymer(s) used for the manufacture of the branched polypropylene (b-PP), i.e. the high melt strength polypropylene (HMS-PP), reference is made to the section "the branched polypropylene".
As stated above it is preferred that the bifunctionally unsaturated monomer(s) and/or multifunctionally unsaturated low molecular weight polymer(s) are used in the presence of a thermally decomposing free radical-forming agent.
Peroxides are preferred thermally decomposing free radical- forming agents. More preferably the thermally decomposing free radical-forming agents are selected from the group consisting of acyl peroxide, alkyl peroxide, hydroperoxide, perester and peroxycarbonate.
The following listed peroxides are in particular preferred: Acyl peroxides: benzoyl peroxide, 4-chlorobenzoyl peroxide, 3-methoxybenzoyl peroxide and/or methyl benzoyl peroxide. Alkyl peroxides: allyl t-butyl peroxide, 2,2-bis(t-butylperoxybutane), l,l-bis(t- butylperoxy)-3,3,5-trimethylcyclohexane, n-butyl-4,4-bis(t-butylperoxy) valerate, diisopropylaminomethyl-t-amyl peroxide, dimethylaminomethyl-t-amyl peroxide, diethylaminomethyl-t-butyl peroxide, dimethylaminomethyl-t-butyl peroxide, 1 , 1 -di-(t- amylperoxy)cyclohexane, t-amyl peroxide, t-butylcumyl peroxide, t-butyl peroxide and/or 1- hydroxybutyl n-butyl peroxide.
Peresters and peroxy carbonates: butyl peracetate, cumyl peracetate, cumyl perpropionate, cyclohexyl peracetate, di-t-butyl peradipate, di-t-butyl perazelate, di-t-butyl perglutarate, di-t-butyl perthalate, di-t-butyl persebacate, 4-nitrocumyl perpropionate, 1 - phenylethyl perbenzoate, phenylethyl nitro-perbenzoate, t-butylbicyclo-(2,2, 1 )heptane percarboxylate, t-butyl-4-carbomethoxy perbutyrate, t-butylcyclobutane percarboxylate, t- butylcyclohexyl peroxycarboxylate, t-butylcyclopentyl percarboxylate, t-butylcyclopropane percarboxylate, t-butyldimethyl percinnamate, t-butyl-2-(2,2-diphenylvinyl) perbenzoate, t- butyl-4-methoxy perbenzoate, t-butylperbenzoate, t-butylcarboxycyclohexane, t-butyl pernaphthoate, t-butyl peroxyisopropylcarbonate, t-butyl pertoluate, t-butyl- 1- phenylcyclopropyl percarboxylate, t-butyl-2-propylperpentene-2-oate, t-butyl- 1- methylcyclopropyl percarboxylate, t-butyl-4-nitrophenyl peracetate, t-butylnitrophenyl peroxycarbamate, t-butyl-N-succiimido percarboxylate, t-butyl percrotonate, t-butyl permaleic acid, t-butyl permethacrylate, t-butyl peroctoate, t-butyl
peroxyisopropylcarbonate, t-butyl perisobutyrate, t-butyl peracrylate and/or t-butyl perpropionate.
Also contemplated are mixtures of these above listed free radical-forming agents. Preferably step (b) is initiated when at least 70 %, preferably at least 80 %, yet more preferably at least 90 %, like at least 95 or 99 %, of the reaction between the polypropylene (PP) and the thermally decomposing free radical- forming agent and optionally the bifunctionally unsaturated monomer has taken place to obtain the branched polypropylene (b-PP), i.e. the high melt strength polypropylene (HMS-PP). In a preferred embodiment, an extruder, such as a twin screw extruder, is used for step (a) and (b).
The use of an extruder is particularly advantageous in that it can simultaneously be used for the preparation of the branched propylene (b-PP), i.e. the high melt strength polypropylene (HMS-PP), and subsequent for adding the polypropylene (ΡΡ') or for adding the additive mixture (AM) to said branched propylene (b-PP). In a preferred embodiment, the polypropylene (PP) is added to an extruder together with - as described in detail above - the thermally decomposing free radical-forming agent, preferably a peroxide, and optionally with the bifunctionally unsaturated monomer(s) and/or with the multifunctionally unsaturated low molecular weight polymer(s), preferably with the bifunctionally unsaturated monomer(s) selected from divinyl compounds, allyl compounds or dienes, to provide the branched polypropylene (b-PP), i.e. the high melt strength polypropylene (HMS-PP), in step (a). It is also possible to use a combination of an extruder downstream a pre-mixing device, wherein the bifunctionally unsaturated monomer(s) and/or the multifunctionally unsaturated low molecular weight polymer(s) and the thermally decomposing free radical- forming agent are add to the polypropylene in the pre-mixing device. Subsequently, in a step (b) the polypropylene (PP')> preferably the linear polypropylene (Ι-ΡΡ'), or the additive mixture (AM) based on said polypropylene (PP')> preferably based on said linear polypropylene (1- PP), comprising the at least one additive (A) is preferably added at the downstream end of the extruder screw in order not to interfere with the modification reaction for providing branched polypropylene (b-PP), i.e. the high melt strength polypropylene (HMS-PP), as described above. In this respect, the term "downstream end of the extruder screw" is understood as within the last 60 % of the length of the extruder screw, preferably within the last 65 % of the length of the extruder screw, more preferably at least 70 % of the length of the extruder screw, like at least 75 % of the extruder screw. Accordingly, the extruder (E) used for the instant process preferably comprises in operation direction a feed-throat (FT), a first mixing zone (MZl), a second mixing zone (MZ2) and a die (D), wherein between the first mixing zone (MZl) and the second mixing zone (MZ2) a side feed-throat (SFT) is located. Preferably the extruder is a screw extruder, like a twin screw extruder. Accordingly the polypropylene (PP), the thermally decomposing free radical- forming agent, preferably a peroxide, and optionally the bifunctionally unsaturated monomer and/or the multifunctionally unsaturated low molecular weight polymer monomer, preferably selected from divinyl compounds, allyl compounds or dienes, but not the polypropylene (PP')> ϊ·β· not the linear polypropylene (Ι-ΡΡ'), and not the additives (A), are fed via the feed-throat (FT), thereby preferably using a feeder, into the extruder and is/are subsequently passed downstream through the first mixing zone (MZl). Preferably the shear stress in said first mixing zone (MZl) is of such extent that the polypropylene (PP) is molten and the chemical reaction with the radical- forming agent and with the optional bifunctionally unsaturated monomer and/or multifunctionally unsaturated low molecular weight polymer is initiated. After the first mixing zone (MZl), i.e. between the first mixing zone (MZl) and the second mixing zone (MZ2), the polypropylene (ΡΡ'), preferably the linear polypropylene (1- PP'), or the additive mixture (AM) is added, i.e. fed into the extruder. Preferably the polypropylene (PP')> preferably the linear polypropylene (Ι-ΡΡ'), or the additive mixture (AM) is added via the side feed-throat (SFT), thereby preferably using a side feeder.
Subsequently all components of the polypropylene composition, including the polypropylene (ΡΡ'), preferably the linear polypropylene (Ι-ΡΡ'), or the additive mixture (AM) are passed downstream through the second mixing zone (MZ2). Finally the polypropylene composition is discharged via the die (D). Preferably, the first mixing zone (MZl) is longer than the second mixing zone (MZ2).
Preferably the length ratio between the first mixing zone (MZl) to the second mixing zone (MZ2) [mm (MZl) / mm (MZ2)] is at least 2/1, more preferably 3/1, yet more preferably in the range of 2/1 to 15/1, still more preferably 3/1 to 10/1. The preparation of the films is accomplished known in the art. For instance the film can be produced by cast film or blown film technology. In the cast film technology the molten polypropylene composition is extruded through a slot extrusion die onto a chill roll to cool the polymer to a solid film. Typically the polypropylene composition is firstly compressed and liquefied in an extruder, it being possible for any additives to be already added to the polymer or introduced at this stage via a masterbatch. The melt is then forced through a flat- film die (slot die), and the extruded film is taken off on one or more take-off rolls, during which it cools and solidifies. It has proven particularly favorable to keep the take-off roll or rolls, by means of which the extruded film is cooled and solidified, at a temperature from 10 to 50 °C, preferably from 10 to 40 °C, more preferably from 12 to 35 °C. The obtained product is an unstretched film which can if desired biaxially stretched.
In the blown film process the polypropylene composition is extruded through an annular die and blown into a tubular film by forming a bubble which is collapsed between nip rollers after solidification. The blown extrusion can be preferably effected at a temperature in the range 160 to 240 °C, and cooled by water or preferably by blowing gas (generally air) at a temperature of 10 to 50 °C to provide a frost line height of 0.5 to 8 times the diameter of the die. The blow up ratio should generally be in the range of from 1.5 to 4, such as from 2 to 4, preferably 2.5 to 3.5.
In the following, the present invention is described in more detail by way of examples.
E X A M P L E S
A. Measuring methods
The following definitions of terms and determination methods apply for the above general description of the invention as well as to the below examples unless otherwise defined. Comonomer content in polypropylene
The comonomer content is determined by quantitative Fourier transform infrared spectroscopy (FTIR) after basic assignment calibrated via quantitative 13C nuclear magnetic resonance (NMR) spectroscopy in a manner well known in the art. Thin films are pressed to a thickness of 250 μιη and spectra recorded in transmission mode.
Specifically, the ethylene content of a polypropylene-co-ethylene copolymer is determined using the baseline corrected peak area of the quantitative bands found at 720-722 and 730- 733 cm"1. Propylene- 1 -butene-copolymers were evaluated at 767 cm"1. Quantitative results are obtained based upon reference to the film thickness.
Melting temperature (Tm) and heat of fusion (Hf), crystallization temperature (Tc) and heat of crystallization (Hc): measured with Mettler TA820 differential scanning calorimetry (DSC) on 5 to 10 mg samples. DSC is run according to ISO 3146 / part 3 /method C2 in a heat / cool / heat cycle with a scan rate of 10 °C/min in the temperature range of +23 to +210°C. Crystallization temperature and heat of crystallization (Hc) are determined from the cooling step, while melting temperature and heat of fusion (Hf) are determined from the second heating step
MFR2 (230 °C) is measured according to ISO 1133 (230 °C, 2.16 kg load).
Strain hardening factor (SHF)
The strain hardening factor is defined as ηι + νε (ή 3η +
wherein
r\g(t, s) is the uniaxial extensional viscosity; and η + (t) is three times the time dependent shear viscosity r\+(t) in the linear range of deformation. The determination of the linear viscoelastic envelop in extension η + (?) , using IRIS Rheo
Hub 2008, required the calculation of the discrete relaxation time spectrum from the storage and loss modulus data (G', G" (ω)). The linear viscoelastic data (G', G" (ω)) is obtained by frequency sweep measurements undertaken at 180 °C for polypropylene or at 140 ° for polyethylene , on a Anton Paar MCR 300 coupled with 25 mm parallel plates. The underlying calculation principles used for the determination of the discrete relaxation spectrum are described in Baumgartel M, Winter HH, "Determination of the discrete relaxation and retardation time spectra from dynamic mechanical data", Rheol.Acta
28:511519 (1989) which is incorporated by reference in its entirety.
IRIS RheoHub 2008 expresses the relaxation time spectrum as a sum of N Maxwell modes o N -—
G(t) = Gegi.e λ>
1
wherein g; and λ; are material parameters and Ge is the equilibrium modulus.
The choice for the maximum number of modes, N used for determination of the discrete relaxation spectrum, is done by using the option "optimum" from IRIS RheoHub 2008. The equilibrium modulus Ge was set at zero. The non- linear fitting used to obtain η+ (?) is performed on IRIS Rheo Hub 2008, using the Doi-Edwards model.
The uniaxial extensional viscosity, η^(ί,έ) is obtained from uniaxial extensional flow measurements, conducted on an Anton Paar MCR 501 coupled with the Sentmanat extensional fixture (SER-1). The temperature for the uniaxial extensional flow measurements was set at 180°C, applying extension (strain) rates θε/dt ranging from 0.3 s"1 to 10 s"1 and covering a range of Hencky strain
ε = 1η [(1 - 10) / 1ο],
with 10 being the original and 1 the actual sample fixation length, from 0.3 to 3.0. Particularly care was taken for the preparation of the samples for extensional flow. The samples were prepared by compression moulding at 230 °C followed by slow cooling to room temperature (forced water or air cooling were not used). This procedure allowed obtaining well shaped samples free of residual stresses. The sample was left for some minutes at the testing temperature to ensure thermal stability (set temperature ±0,1 °C), before carrying out the uniaxial extensional flow measurements.
F30 melt strength and V30 melt extensibility
The test described herein follows ISO 16790:2005.
The strain hardening behaviour is determined by the method as described in the article "Rheotens-Mastercurves and Drawability of Polymer Melts", M. H. Wagner, Polymer Engineering and Sience, Vol. 36, pages 925 to 935. The content of the document is included by reference. The strain hardening behaviour of polymers is analysed by Rheotens apparatus (product of Gottfert, Siemensstr.2, 74711 Buchen, Germany) in which a melt strand is elongated by drawing down with a defined acceleration.
The Rheotens experiment simulates industrial spinning and extrusion processes. In principle a melt is pressed or extruded through a round die and the resulting strand is hauled off. The stress on the extradate is recorded, as a function of melt properties and measuring parameters (especially the ratio between output and haul-off speed, practically a measure for the extension rate). For the results presented below, the materials were extruded with a lab extruder HAAKE Polylab system and a gear pump with cylindrical die (L/D = 6.0/2.0 mm). The gear pump was pre-adjusted to a strand extrusion rate of 5 mm/s, and the melt temperature was set to 200°C. The spinline length between die and Rheotens wheels was 80 mm. At the beginning of the experiment, the take-up speed of the Rheotens wheels was adjusted to the velocity of the extruded polymer strand (tensile force zero): Then the experiment was started by slowly increasing the take-up speed of the Rheotens wheels until the polymer filament breaks. The acceleration of the wheels was small enough so that the tensile force was measured under quasi-steady conditions. The acceleration of the melt strand drawn down is 120 mm/sec2. The Rheotens was operated in combination with the PC program EXTENS. This is a real-time data-acquisition program, which displays and stores the measured data of tensile force and drawdown speed. The end points of the Rheotens curve (force versus pulley rotary speed) is taken as the F30 melt strength and drawability values. OCS gel index
1. Apparatus
The apparatus consists of a laboratory extruder ME 25/5200 VI with three heating zones, an adapter and a 150 mm broad die. The follow-on unit encompasses a chillroll CR - 8, diameter 140 mm, including Haake C40P heating- and cooling device (15 to 90 °C), a line scan camera FS -5 / 4096 Pixel (dynamical digital converting of gray scale images) and a wind-up unit with automatic tension control up to 10 N.
2. Material-specific settings for film- manufacturing
The temperature setting for the heating zones at cylinder and die is classified for polypropylene according to MFR-ranges in three groups:
Group 1 : MFR-range 0.3-2.0 g/10 min (230 °C/2.16 kg), temperatures
220/260/270/280/290 °C
Group 2: MFR-range 2.0-10 g/10 min (230 °C/2.16 kg), temperatures
220/230/240/250/260 °C
Group 3 : MFR-range 10-33 g/10 min (230 °C/2.16 kg), temperatures
200/220/230/240/240 °C
Preset Parameters:
Rotational speed (screw): 30 rpm
Haul-off speed: 3 m/min;
The film thickness is 50 μιη
3. Measurement
After fulfilment of the following parameters: In case of similar materials ca. 60 min running- in period, in case of highly diverging materials ca. 120 min.
Goal: Adjustment of a homogenous film at constant melt pressure and melt temperature. The measuring area is standardised at 5 m2. The measurement itself is terminated automatically when the area is accomplished. The report will be printed simultaneously.
4. Analysis
The number of found defects is, referring 1/m2, class-divided according to size and multiplied with the mass factor, adding up to the gelindex.
Size class 1 100-300 μιη mass factor x 0.1
Size class 2 301-600 μιη mass factor x 1.0 Size class 3 601-1000 μηι mass factor x 5.0
Size class 4 > 1000 μηι mass factor x 10
Example:
17 defects size class 1 x O.l = 1.7
5 defects size class 2 x 1.0 = 5.0
2 defects size class 3 x 5.0 = 10.0
0 defects size class 4 x 10.0 = 0
gelindex = 16.7
Particle size/Particle size distribution
A gradation test was performed on the polymer samples. The sieve analysis involved a nested column of sieves with wire mesh screen with the following sizes: >20 μηι, >32 μηι, >63 μιη, >100 μιη, >125 μιη, >160 μιη, > 200 μιη, >250 μιη, > 315 μιη, > 400 μιη, >500 μηι, >710 μηι, >1 mm, >1.4 mm, > 2 mm, >2.8 mm. The samples were poured into the top sieve which has the largest screen openings. Each lower sieve in the column has smaller openings than the one above (see sizes indicated above). At the base is the receiver. The column was placed in a mechanical shaker. The shaker shook the column. After the shaking was completed the material on each sieve was weighed. The weight of the sample of each sieve was then divided by the total weight to give a percentage retained on each sieve. B. Examples
Linear polypropylene (1-PP)
1-PPl is a linear propylene homopolymer having a MFR2 (230°C) of 0.37 g/lOmin, a d5o of 1,100 μηι, a dgo of 1,650 μηι, a melting temperature Tm of 164 °C, a F30 melt strength of 68 cN and V30 melt extensibility 146 mm/s.
1-PP2 is a linear propylene homopolymer having a MFR2 (230°C) of 3.48 g/lOmin, a d5o of 220 μηι, a dgo of 300 μηι, a melting temperature Tm of 160 °C, a F30 melt strength of 6.5 cN and V30 melt extensibility 160 mm/s.
1-PP3 is a linear propylene homopolymer having a MFR2 (230°C) of 3.39 g/lOmin, a d5o of 700 μηι, a dgo of 1,100 μηι, a melting temperature Tm of 159 °C, a F30 melt strength of 8.2 cN and V30 melt extensibility 155 mm/s. Additive mixture
The linear polypropylenes 1-PP2 was used to provide additive mixture (AM) containing further additives as a masterbatch for incorporating into a base polymer of branched polypropylene. The additive mixture contains 87.50 wt.-% of the linear polypropylenes 1- PP1, 10.00 wt.-% Irganox B 225 FF (antioxidant), and 2.50 wt.-% Hydrotalcit.
Inventive Examples IE1 to IE 5 and comparative example CE1:
1-PPl for the comparative example CE1, 1-PP2 for the inventive examples IE1 to IE4, and 1- PP3 for the inventive example IE5 were subjected to a reactive extrusion in the presence of butadiene and peroxide as described in the following. Both the butadiene and the peroxide (75 % solution of tert-butylperoxy isopropyl carbonate "Trigonox BPIC-C75" of Akzo
Nobel) (amounts are indicated in table 3) were pre-mixed with the 1-PPl powder prior or 1- PP2 powder to the melt-mixing step in a horizontal mixer with paddle stirrer at a temperature of 65°C, maintaining an average residence time of 15 to 20 minutes. The pre-mixture was transferred under inert atmosphere to a co-rotating twin screw extruder of the type Theyson TSK60 having a barrel diameter of 60 mm and an L/D-ratio of 48 equipped with a high intensity mixing screw having 3 kneading zones and a two-step degassing setup. The melt temperature profile is given in table 1. The screw speed and throughput is indicated in table 2. In the first 3/4 of the extruder length the branched polypropylene is produced (b-PP). Subsequently, via a side feeder, i.e. at the last 1/4 of the extruder length, the additive mixture is fed into the extruder to the produced branched polypropylene (b-PP) The extruded polypropylene composition was discharged and pelletized. From the pellets films have been produced as described above (OCS gel index). The final properties are indicated in table 3.
Table 1 : Set temperature profile in the extruder
Zone 1 to 6 7 8 and 9 10 and 11 12 13 14
Temperature [°C] 240 230 220 230 230 220 230 Table 2: Process conditions
Figure imgf000039_0001
based on the total amount of the polypropylene composition
Table 3: Properties of polypropylene composition
MFR2 F30 V30 OCS gel index
[g/lOmin] [cN] [mm/s] [-]
IE1 8.7 7.0 256 29
IE2 9.1 7.6 259 20
IE3 11.4 8.0 261 48
IE4 10.2 8.3 269 117
IE5 8.9 8.1 239 83
CE1 11.4 5.7 252 1785

Claims

C LA I M S
Process for providing a polypropylene composition comprising at least 90 wt.-% of a branched polypropylene (b-PP), the process comprises at least a step (a) in which a polypropylene (PP) is reacted with a thermally decomposing free radical- forming agent and optionally with bifunctionally unsaturated monomer(s) and/or with multifunctionally unsaturated low molecular weight polymer(s) obtaining thereby the branched polypropylene (b-PP),
wherein
(c) the polypropylene (PP) has a melt flow rate MFR2 (230°C) of 3.0 to
13.0 g/10min;
(d) the polypropylene composition and/or the branched polypropylene (b-PP) has/have a F30 melt strength of more than 5.8 cN and a V30 melt extensibility of more than 200 mm/s, wherein the F30 melt strength and the V30 melt extensibility are measured according to ISO 16790:2005.
Process according to claim 1 , wherein the polypropylene (PP)
(a) is a propylene homopolymer;
and/or
(b) is a linear polypropylene (1-PP) having preferably a F30 melt strength of more than 1.0 cN and a V30 melt extensibility of below 200 mm/s, wherein the F30 melt strength and the V30 melt extensibility are measured according to ISO 16790:2005.
Process according to claim 2, wherein the linear polypropylene (1-PP) has a F30 melt strength of more than 1.0 to 65.0 cN and a V30 melt extensibility of below 200 mm/s, preferably below 190 mm/s, wherein the F30 melt strength and the V30 melt extensibility are measured according to ISO 16790:2005. 4. Process according to anyone of the preceding claims, wherein
(a) the thermally decomposing free radical- forming agent is a peroxide and/or
(b) the bifunctionally unsaturated monomer is selected from the group
consisting of divinyl compounds, allyl compounds and dienes.
Process according to anyone of the preceding claims, wherein the process comprises subsequent to step (a) a further step (b), in which to the branched polypropylene (b- PP) a polypropylene (ΡΡ') having a melt flow rate MFR2 (230°C) of 1 to 18 g/lOmin is added. 6. Process according to claim 5, wherein step (b) is initiated when at least 80 % of the reaction between the polypropylene (PP) and the thermally decomposing free radical- forming agent and optionally the bifunctionally unsaturated monomer has taken place. 7. Process according to claim 5 or 6, wherein the polypropylene (ΡΡ') is a linear
polypropylene (Ι-ΡΡ'), said linear polypropylene (Ι-ΡΡ') preferably has a F30 melt strength of more than 1.0 cN and a V30 melt extensibility of below 200 mm/s, more preferably has a F30 melt strength of more than 1.0 to 65.0 cN and a V30 melt extensibility of below 200 mm/s, wherein the F30 melt strength and the V30 melt extensibility are measured according to ISO 16790:2005.
Process according to anyone of the preceding claims, wherein the linear polypropylene (1-PP) and/or the linear polypropylene (Ι-ΡΡ') has/have
(a) a particle size distribution dgo of below 1,500 μιη;
and/or
(b) a particle size distribution d5o of below 1,000 μιη;
and/or
(c) a d9o/d5o ratio of below 1.80.
The process according to anyone of the preceding claims, wherein the step (a) and the optional step (b) are accomplished in an extruder, said extruder preferably comprises in operation direction a first mixing zone (MZ1) and a second mixing zone (MZ2), wherein further the step (a) takes place in the first mixing zone (MZ2) whereas step (b) takes place in the second mixing zone (MZ2). 10. The process according to claim 9, wherein the extruder comprises in operation direction a feed-throat (FT), the first mixing zone (MZ1), the second mixing zone (MZ2) and a die (D), wherein between the first mixing zone (MZ1) and the second mixing zone (MZ2) a side feed-throat (SFT) is located, wherein further the polypropylene (PP), the thermally decomposing free radical- forming agent, and optionally the biiunctionally unsaturated monomer are fed via the feed-throat (FT) and the polypropylene (ΡΡ') is fed via the side feed-throat (SFT).
11. The process according to claim 9 or 10, wherein
(a) the reaction between the polypropylene (PP) and the thermally decomposing free radical-forming agent and optionally the bifunctionally unsaturated monomer takes place in the first mixing zone (MZ1);
and/or
(b) not more than 10 wt.-% of the total amount of the branched polypropylene (b-PP) of the polypropylene composition is produced in the second mixing zone (MZ2).
12. The process according to anyone of the preceding claims 5 to 11, wherein 1 to 5 parts by weight of the polypropylene (ΡΡ') are added to 95 to 99 parts by weight of branched polypropylene (b-PP), preferably wherein 1 to 3 parts by weight of the polypropylene (ΡΡ') are added to 97 to 99 parts by weight of branched
polypropylene (b-PP), more preferably wherein 2 parts by weight of the polypropylene (ΡΡ') are added to 98 parts by weight of branched polypropylene (b- PP).
13. The process according to anyone of the preceding claims, wherein (a) the polypropylene (ΡΡ') comprises at least one additive (A) selected from the group consisting of antioxidants, metal deactivators, UV-stabilizers, antistatic agents, antifogging agents, acid scavengers, blowing agents, cling agents, lubricants, nucleating agents, slip agents, antiblocking agents and mixtures thereof;
and/or
(b) the branched polypropylene (b-PP) is free of additives (A).
14. The process according to anyone of the preceding claims, wherein the resulting polypropylene composition has
(a) a F30 melt strength of 5.8 to 20.0 cN and a V30 melt extensibility of 210 to 300 mm/s;
and/or
(b) a gel index of less than 1,500, preferably less than 1,000.
15. The process according to anyone of the preceding claims, wherein the resulting polypropylene composition is further defined by anyone of the claims 16 to 18.
16. Polypropylene composition comprising
(b) 95 to 99 parts by weight of a branched polypropylene (b-PP); and
(b) 1 to 5 parts by weight of a polypropylene (ΡΡ') having a melt flow rate
MFR2 (230 °C) measured according to ISO 1133 of more than 1.0 to 18.0 g/lOmin,
wherein the polypropylene composition has
a melt flow rate MFR2 (230 °C) measured according to ISO 1133 of 7.0 to 13.0 g/lOmin, and
a gel index of less than 1 ,000, preferably below 800;
and wherein the polypropylene composition and/or the branched polypropylene (b- PP) has/have a F30 melt strength of 5.8 to 13.0 cN and a V30 melt extensibility of 210 to 300 mm/s, wherein the F30 melt strength and the V30 melt extensibility are measured according to ISO 16790:2005.
17. Polypropylene composition according to claim 16, wherein the polypropylene composition comprises at least one additive (A) selected from the group consisting of antioxidants, metal deactivators, UV-stabilizers, antistatic agents, antifogging agents, acid scavengers, blowing agents, cling agents, lubricants, nucleating agents, slip agents, antiblocking agents and mixtures thereof.
18. Process of anyone of preceding claims 1 to 15 or polypropylene composition
according to claim 16 or 17, wherein the propylene composition and/or the branched polypropylene (b-PP) has/have a strain hardening factor (SHF) of at least 1.9, preferably in the range of 1.9 to 7.0, more preferably in the range of 1.9 to 6.5, measured at a strain rate of 3.0 s"1 and a Hencky strain of 2.5.
19. Film comprising the polypropylene composition according to anyone of the
preceding claims 16 to 18.
PCT/EP2013/065263 2012-07-25 2013-07-19 Film with low ocs gel index WO2014016206A1 (en)

Priority Applications (10)

Application Number Priority Date Filing Date Title
CA2878305A CA2878305C (en) 2012-07-25 2013-07-19 Film with low ocs gel index
JP2015523504A JP5986314B2 (en) 2012-07-25 2013-07-19 Film with low OCS gel index
BR112015000853A BR112015000853A2 (en) 2012-07-25 2013-07-19 low gel ocs index film
ES13739223.9T ES2626363T3 (en) 2012-07-25 2013-07-19 OCS gel low index film
US14/414,825 US9376549B2 (en) 2012-07-25 2013-07-19 Film with low OCS gel index
IN10848DEN2014 IN2014DN10848A (en) 2012-07-25 2013-07-19
EP13739223.9A EP2877535B1 (en) 2012-07-25 2013-07-19 Film with low ocs gel index
KR1020157003771A KR101531814B1 (en) 2012-07-25 2013-07-19 Film with low ocs gel index
MX2015000615A MX366376B (en) 2012-07-25 2013-07-19 Film with low ocs gel index.
CN201380037223.9A CN104718249B (en) 2012-07-25 2013-07-19 Thin film with low OCS gel indexs

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
EP12177878.1 2012-07-25
EP12177878 2012-07-25

Publications (1)

Publication Number Publication Date
WO2014016206A1 true WO2014016206A1 (en) 2014-01-30

Family

ID=48803558

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/EP2013/065263 WO2014016206A1 (en) 2012-07-25 2013-07-19 Film with low ocs gel index

Country Status (11)

Country Link
US (1) US9376549B2 (en)
EP (1) EP2877535B1 (en)
JP (1) JP5986314B2 (en)
KR (1) KR101531814B1 (en)
CN (1) CN104718249B (en)
BR (1) BR112015000853A2 (en)
CA (1) CA2878305C (en)
ES (1) ES2626363T3 (en)
IN (1) IN2014DN10848A (en)
MX (1) MX366376B (en)
WO (1) WO2014016206A1 (en)

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2014195114A1 (en) * 2013-06-05 2014-12-11 Borealis Ag One-step production of a polypropylene composition
JP2015522700A (en) * 2012-07-25 2015-08-06 ボレアリス・アクチェンゲゼルシャフトBorealis Ag Foam made from low gel content polypropylene
EP3018154A1 (en) * 2014-11-05 2016-05-11 Borealis AG Long-chain branched polypropylene for film application
EP3018155A1 (en) * 2014-11-05 2016-05-11 Borealis AG Branched polypropylene for film applications
WO2016124617A1 (en) * 2015-02-04 2016-08-11 Borealis Ag Process for producing modified olefin polymer in an extruder
CN107428884A (en) * 2015-04-10 2017-12-01 博里利斯股份公司 Method for olefin polymer to be mixed with reactant
EP3333221A1 (en) 2016-12-09 2018-06-13 Borealis AG Polypropylene composition for foaming applications
US20180298174A1 (en) * 2015-10-21 2018-10-18 Borealis Ag Long-branched polypropylene composition with increased melt strength stability
US10316177B2 (en) 2014-11-05 2019-06-11 Borealis Ag Long-chain branched polypropylene for foam application
WO2021001174A1 (en) * 2019-07-04 2021-01-07 Borealis Ag Long-chain branched propylene polymer composition
WO2024038070A1 (en) * 2022-08-19 2024-02-22 Borealis Ag Process for preparing a long chain branched polypropylene composition

Families Citing this family (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN107709008A (en) 2015-08-13 2018-02-16 埃克森美孚化学专利公司 Multi-layer sheet containing high melt strength, propylene
CN109312092B (en) * 2016-08-18 2021-06-01 日本聚丙烯株式会社 Polypropylene resin composition for microporous film and use thereof
EP3562873B1 (en) * 2016-12-30 2023-09-06 Borealis AG Low emission polypropylene foam sheets
US11572462B2 (en) 2017-02-07 2023-02-07 Exxonmobil Chemical Patents Inc. High melt strength polypropylenes with improved processability
WO2018147944A1 (en) * 2017-02-07 2018-08-16 Exxonmobil Chemical Patents Inc. High melt strength polypropylenes with improved processability
WO2019013872A1 (en) 2017-07-13 2019-01-17 Exxonmobil Chemical Patents Inc. Process to produce strain hardened polypropylene
JP6742044B2 (en) * 2017-09-21 2020-08-19 株式会社Tbm Thermoplastic resin composition and molded article using the same
ES2974283T3 (en) * 2017-10-25 2024-06-26 Borealis Ag Loaded polypropylene composition with improved thermo-mechanical properties
WO2020231526A1 (en) 2019-05-15 2020-11-19 Exxonmobil Chemical Patents Inc. Polypropylene-based compositions
HUE065425T2 (en) 2021-04-01 2024-05-28 Borealis Ag Polymer composition suitable for making films
CN114058115B (en) * 2021-08-31 2023-06-06 成都金发科技新材料有限公司 Antibacterial and antiviral high-impact polypropylene composition and preparation method and application thereof

Citations (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0787750A2 (en) 1996-02-01 1997-08-06 PCD-Polymere Gesellschaft m.b.H. Poly(alkylethylene) structural isomers
EP0879830A1 (en) 1997-05-20 1998-11-25 PCD Polymere AG Modified polypropylene having improved processability
EP0890612A2 (en) 1997-07-09 1999-01-13 PCD Polymere AG Polyolefin molded parts of improved stifness and heat resistance
US20070004861A1 (en) * 2005-07-01 2007-01-04 Kevin Cai High melt strength polypropylene resins and method for making same
EP1892264A1 (en) 2006-08-25 2008-02-27 Borealis Technology Oy Extrusion coated substrate
WO2008022802A1 (en) 2006-08-25 2008-02-28 Borealis Technology Oy Blown film of polypropylene
EP2000504A1 (en) * 2007-06-08 2008-12-10 Borealis Technology Oy Polymer composition with high impact resistance and high melt strength
US20100047544A1 (en) * 2006-08-31 2010-02-25 Treofan Germany Gmbh & Co. Kg Biaxially oriented electrical insulating film
US20100063212A1 (en) * 2007-01-31 2010-03-11 Borealis Technology Oy Use of polypropylene having chain branching to broaden the processing window in the injection stretch blow molding
WO2011141070A1 (en) * 2010-05-11 2011-11-17 Borealis Ag Polypropylene composition suitable for extrusion coating
EP2492293A1 (en) * 2011-02-28 2012-08-29 Borealis AG Polypropylene composition suitable for extrusion coating

Family Cites Families (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4957968A (en) * 1988-08-09 1990-09-18 Monsanto Company Adhesive thermoplastic elastomer blends
JPH09309966A (en) 1996-05-23 1997-12-02 Kanegafuchi Chem Ind Co Ltd Foam made from modified polypropylene resin composition
US6087431A (en) 1997-04-14 2000-07-11 Asahi Kasei Kagyo Kabushiki Kaisha Olefinic thermoplastic elastomer composition
JPH11302425A (en) 1998-04-21 1999-11-02 Sekisui Chem Co Ltd Expandable polyolefin resin composition having fluidity
JP2002173564A (en) 2000-12-06 2002-06-21 Grand Polymer Co Ltd Modified polypropylene resin composition, method for producing the same and foamed article produced therefrom
US6646056B2 (en) 2001-10-16 2003-11-11 Solvay Engineered Polymers Thermoplastic elastomer compositions
JP4010141B2 (en) 2001-12-06 2007-11-21 住友化学株式会社 Modified polypropylene resin and method for producing the same
PL2072546T5 (en) 2007-12-18 2013-05-31 Borealis Tech Oy Heterophasic polypropylene with high impact properties
EP2113541A1 (en) * 2008-04-28 2009-11-04 Borealis AG Adhesive propylene polymer composition suitable for extrusion coating of paper substrates
EP2338931A1 (en) 2009-12-23 2011-06-29 Borealis AG Blown grade showing superior stiffness, transparency and processing behaviour
ES2599456T3 (en) * 2012-06-28 2017-02-01 Borealis Ag High melt strength polypropylene with improved quality
MX2015000614A (en) 2012-07-25 2015-04-10 Borealis Ag Foam produced from polypropylene with low gel content.

Patent Citations (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0787750A2 (en) 1996-02-01 1997-08-06 PCD-Polymere Gesellschaft m.b.H. Poly(alkylethylene) structural isomers
EP0879830A1 (en) 1997-05-20 1998-11-25 PCD Polymere AG Modified polypropylene having improved processability
EP0890612A2 (en) 1997-07-09 1999-01-13 PCD Polymere AG Polyolefin molded parts of improved stifness and heat resistance
US6077907A (en) * 1997-07-09 2000-06-20 Borealis Ag Molded polyolefin parts of improved dimensional stability at elevated temperatures and improved stiffness
US20070004861A1 (en) * 2005-07-01 2007-01-04 Kevin Cai High melt strength polypropylene resins and method for making same
EP1892264A1 (en) 2006-08-25 2008-02-27 Borealis Technology Oy Extrusion coated substrate
WO2008022802A1 (en) 2006-08-25 2008-02-28 Borealis Technology Oy Blown film of polypropylene
US20100047544A1 (en) * 2006-08-31 2010-02-25 Treofan Germany Gmbh & Co. Kg Biaxially oriented electrical insulating film
US20100063212A1 (en) * 2007-01-31 2010-03-11 Borealis Technology Oy Use of polypropylene having chain branching to broaden the processing window in the injection stretch blow molding
EP2000504A1 (en) * 2007-06-08 2008-12-10 Borealis Technology Oy Polymer composition with high impact resistance and high melt strength
WO2011141070A1 (en) * 2010-05-11 2011-11-17 Borealis Ag Polypropylene composition suitable for extrusion coating
EP2492293A1 (en) * 2011-02-28 2012-08-29 Borealis AG Polypropylene composition suitable for extrusion coating

Non-Patent Citations (3)

* Cited by examiner, † Cited by third party
Title
BAUMGÄRTEL M; WINTER HH: "Determination of the discrete relaxation and retardation time spectra from dynamic mechanical data", RHEOL.ACTA, vol. 28, 1989, pages 511 - 519, XP002088775, DOI: doi:10.1007/BF01332922
M. H. WAGNER: "Rheotens-Mastercurves and Drawability of Polymer Melts", POLYMER ENGINEERING AND SIENCE, vol. 36, pages 925 - 935, XP009151017, DOI: doi:10.1002/pen.10480
NELLO PASQUINI: "Polypropylene Handbook, 2nd Edition,", HANSER, pages: 405 - 414

Cited By (29)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2015522700A (en) * 2012-07-25 2015-08-06 ボレアリス・アクチェンゲゼルシャフトBorealis Ag Foam made from low gel content polypropylene
US9290600B2 (en) 2012-07-25 2016-03-22 Borealis Ag Foam produced from polypropylene with low gel content
US10179851B2 (en) 2013-06-05 2019-01-15 Borealis Ag One-step production of a polypropylene composition
WO2014195114A1 (en) * 2013-06-05 2014-12-11 Borealis Ag One-step production of a polypropylene composition
US10457766B2 (en) 2014-11-05 2019-10-29 Borealis Ag Long-chain branched polypropylene for film application
WO2016071400A1 (en) * 2014-11-05 2016-05-12 Borealis Ag Branched polypropylene for film applications
EP3018154A1 (en) * 2014-11-05 2016-05-11 Borealis AG Long-chain branched polypropylene for film application
WO2016071388A3 (en) * 2014-11-05 2016-09-01 Borealis Ag Long-chain branched polypropylene for film application
CN107075014A (en) * 2014-11-05 2017-08-18 博里利斯股份公司 The long-chain branching polypropylene applied for film
JP2017532422A (en) * 2014-11-05 2017-11-02 ボレアリス エージー Long chain branched polypropylene for film applications
US10316177B2 (en) 2014-11-05 2019-06-11 Borealis Ag Long-chain branched polypropylene for foam application
EP3018155A1 (en) * 2014-11-05 2016-05-11 Borealis AG Branched polypropylene for film applications
CN107075014B (en) * 2014-11-05 2019-12-06 博里利斯股份公司 Long chain branched polypropylene for membrane applications
TWI616463B (en) * 2015-02-04 2018-03-01 柏列利斯股份公司 Process for producing modified olefin polymer in an extruder
US10105908B2 (en) 2015-02-04 2018-10-23 Borealis Ag Process for producing modified olefin polymer in an extruder
JP2018504486A (en) * 2015-02-04 2018-02-15 ボレアリス エージー Process for producing modified olefin polymers in an extruder
WO2016124617A1 (en) * 2015-02-04 2016-08-11 Borealis Ag Process for producing modified olefin polymer in an extruder
JP2018510942A (en) * 2015-04-10 2018-04-19 ボレアリス エージー Process for mixing olefin polymers with reactants
US20180142068A1 (en) * 2015-04-10 2018-05-24 Borealis Ag Process for mixing olefin polymer with reactants
US11028238B2 (en) 2015-04-10 2021-06-08 Borealis Ag Process for mixing olefin polymer with reactants
CN107428884B (en) * 2015-04-10 2020-11-13 博里利斯股份公司 Process for mixing an olefin polymer with reactants
CN107428884A (en) * 2015-04-10 2017-12-01 博里利斯股份公司 Method for olefin polymer to be mixed with reactant
US20180298174A1 (en) * 2015-10-21 2018-10-18 Borealis Ag Long-branched polypropylene composition with increased melt strength stability
US10676604B2 (en) 2015-10-21 2020-06-09 Borealis Ag Long-branched polypropylene composition with increased melt strength stability
WO2018104524A1 (en) 2016-12-09 2018-06-14 Borealis Ag Polypropylene composition for foaming applications
US10920057B2 (en) 2016-12-09 2021-02-16 Borealis Ag Polypropylene composition for foaming applications
EP3333221A1 (en) 2016-12-09 2018-06-13 Borealis AG Polypropylene composition for foaming applications
WO2021001174A1 (en) * 2019-07-04 2021-01-07 Borealis Ag Long-chain branched propylene polymer composition
WO2024038070A1 (en) * 2022-08-19 2024-02-22 Borealis Ag Process for preparing a long chain branched polypropylene composition

Also Published As

Publication number Publication date
CN104718249B (en) 2017-03-29
BR112015000853A2 (en) 2017-06-27
EP2877535A1 (en) 2015-06-03
US9376549B2 (en) 2016-06-28
EP2877535B1 (en) 2017-03-15
CN104718249A (en) 2015-06-17
CA2878305C (en) 2017-07-04
JP5986314B2 (en) 2016-09-06
KR20150030767A (en) 2015-03-20
MX366376B (en) 2019-07-05
CA2878305A1 (en) 2014-01-30
KR101531814B1 (en) 2015-06-25
ES2626363T3 (en) 2017-07-24
MX2015000615A (en) 2015-04-14
IN2014DN10848A (en) 2015-09-04
JP2015522701A (en) 2015-08-06
US20150133590A1 (en) 2015-05-14

Similar Documents

Publication Publication Date Title
CA2878305C (en) Film with low ocs gel index
US9410034B2 (en) High melt strength polypropylene of improved quality
US9290600B2 (en) Foam produced from polypropylene with low gel content
US10179851B2 (en) One-step production of a polypropylene composition

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 13739223

Country of ref document: EP

Kind code of ref document: A1

DPE1 Request for preliminary examination filed after expiration of 19th month from priority date (pct application filed from 20040101)
ENP Entry into the national phase

Ref document number: 2878305

Country of ref document: CA

ENP Entry into the national phase

Ref document number: 2015523504

Country of ref document: JP

Kind code of ref document: A

WWE Wipo information: entry into national phase

Ref document number: 14414825

Country of ref document: US

Ref document number: MX/A/2015/000615

Country of ref document: MX

NENP Non-entry into the national phase

Ref country code: DE

ENP Entry into the national phase

Ref document number: 20157003771

Country of ref document: KR

Kind code of ref document: A

REEP Request for entry into the european phase

Ref document number: 2013739223

Country of ref document: EP

WWE Wipo information: entry into national phase

Ref document number: 2013739223

Country of ref document: EP

REG Reference to national code

Ref country code: BR

Ref legal event code: B01A

Ref document number: 112015000853

Country of ref document: BR

ENP Entry into the national phase

Ref document number: 112015000853

Country of ref document: BR

Kind code of ref document: A2

Effective date: 20150114