NL9200603A - A POLYMER COMPOSITION CONTAINING A MIXTURE OF A POLYOLEFINE AND A POLYMER BASED ON VINYLAROMATIC AND DICARBONIC ACID ANHYDRIDE MONOMERS. - Google Patents

Description

A POLYMER COMPOSITION CONTAINING A MIXTURE OF A POLYOLEFINE AND A POLYMER BASED ON VINYL AROMATIC AND DICARBONIC ACID ANHYDRIDE MONOMERS

The invention relates to a polymer composition comprising a mixture of a polyolefin (A) and a polymer (B), based on vinyl aromatic and dicarboxylic anhydride monomer units.

Such a polymer composition is known from WO-A-9005759. WO-A-9005759 discloses a polymer blend of a polyolefin and a second polymer, such as a copolymer of styrene and maleic anhydride. Since the polyolefin and the second polymer are immiscible, a compatibilizer is present in the polymer mixture. The compatibilizer, according to this publication, is a block copolymer of a vinyl aromatic compound and a conjugated diene or partially hydrogenated derivatives thereof.

Compatibilizer is understood here and hereinafter to mean a compound that improves the compatibility of A and B and is located mainly at the interface of polyolefin A and polymer B. Compatible here and hereinafter means: compatible.

From JP-A-63,205,341 it is known to use styrene-containing rubbery copolymers as compatibilizers in polymer compositions consisting of polypropylene and styrene-maleic anhydride copolymer.

However, a drawback of these polymer compositions is that the impact strength-stiffness combination (Izod - Modulus of elasticity) is poor, making the polymer compositions unsuitable for use in structural moldings used in e.g. cars and furniture.

The object of the invention is to provide a polymer composition of a polyolefin A and a polymer B, composed of vinyl aromatic monomer units and dicarboxylic anhydride monomer units, which has a good impact strength-stiffness combination. A further advantage of the polymer composition according to the invention is that it also has good scratch resistance and paintability.

The invention is characterized in that the polymer B is cross-linked. The crosslinking of the polymer B can be both chemical and physical in nature. Physical cross-linking is effected under the influence of van der Waals forces, dippol-dipole interactions and ionic interactions.

Polymer B can be chemically cross-linked by reaction with a compound containing at least two functional groups that can react with the dicarboxylic anhydride group of the polymer.

A first group of possible compounds, suitable for cross-linking the polymer B, form the compounds with two or more alcohol or thiol functional groups. The combination of alcohol and thiol functional groups in a compound is also possible. Preferably these are compounds having two or more alcohol functional groups, such as, 1,4-butanediol, 1,6-hexanediol, pentaerythritol, ethylene glycol and propylene glycol and polymers thereof. Polyhydroxy ethers can also be used, for example polyhydroxy ethers based on bisphenol-A.

A second group of compounds suitable for cross-linking polymer B form the compounds having two or more primary or secondary amine functional groups; preferably primary amine groups. As examples of these compounds with amine functional groups can be mentioned: alkane diamines with a C4-C20 alkane group, such as 1,4-diaminobutane and 1,6-diaminohexane, polyoxyethylene diamine, polyoxypropylene diamine, polyoxypropylene triamine and diphenyl sulfone diamine.

The combination of one or more primary amine groups with one or more secondary amine groups in a compound is possible. Polyamides can also be used. The compound suitable for cross-linking polymer B can also contain at least one alcohol or thiol group and also at least one amine group. Diethanolamine and monoethanolamine are examples of this type of compound.

A third group of compounds, suitable for cross-linking polymer B, form the compounds having two or more epoxide functional groups of the general formula:

where n> 2 and R is a hydrocarbon radical or a hydrogen atom. As examples of such compounds, mention may be made of polyglycidyl ethers of polyhydroxyl-substituted compounds. These compounds can be divided into aromatic type polyepoxide compounds such as those obtainable from bisphenol A and aliphatic type polyepoxide compounds such as polyglycidyl ethers of polyalcohols. As examples of the latter type of polyepoxide compounds can be mentioned: diglycidyl ethers of α-ω diols such as the diglycidyl ether of butanediol, of hexanediol, of paracyclohexyl-dimethanol, of neopentyl glycol and of bisphenol-A. Preferably, compounds resulting from the epoxidation of olefins, such as epoxidized soybean oil, are used.

When crosslinking with an epoxide compound it is usually desirable to use an activator such as an imidazole, a quaternary ammonium salt or a tertiary amine.

A fourth compound, suitable for cross-linking polymer B, is the compounds containing 2 or more oxazoline groups. 1,3-phenyl bisoxazoline may be mentioned as an example of these compounds.

A fifth group of compounds, suitable for cross-linking the polymer B, form the compounds with 2 or more isocyanate groups. Examples of these compounds are toluene-2,4-diisocyanate, benzene-1,3,5-triisocyanate, methane diphenyl diisocyanate.

A sixth group of compounds suitable for cross-linking polymer B form salts of metal atoms from groups II-VIII of the Periodic System. Preferably, metal alkoxides and salts of divalent positive ions are used, such as tetrabutoxy titanium, zinc oxide and zinc acetate.

A compound having two or more functional groups selected from one of the aforementioned groups is suitable for cross-linking the polymer B.

A mixture of one or more compounds suitable for cross-linking polymer B selected from one or more of the above six groups of compounds is also applicable.

The compound suitable for cross-linking polymer B is present in the polymer mixture in an amount of 0.1-20 mol% relative to the amount of dicarboxylic anhydride monomers present in polymer B.

Polyolefins A that can be used in a polymer composition according to the invention are homopolymers, copolymers, terpolymers, or mixtures thereof. Polymers of α-olefins are preferably used and these α-olefins have 2 to 20 carbon atoms. Particular preference is given to the use of polymers of α-olefins with 2-6 carbon atoms »

The polyolefins are made up of olefins such as ethylene, propylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-octene, 1-decene, 4-ethyl-1-hexene, etc. Examples of particularly suitable polyolefins are: low density polyethylene, high density polyethylene, linear low density polyethylene, ultra-low density polyethylene, polypropylene, (high and low density) poly (1-butene), poly (4-methyl-1-pentene), ethylene propylene copolymers, copolymers of ethylene and / or propylene with other copolymerizable monomers, such as ethylene-1-butene copolymer, ethylene-vinyl acrylate copolymer, ethylene-vinyl acetate. Polymers and copolymers of halogenated olefins can also be used.

In the polymer composition, an amount of 30-95 wt.% Of the polyolefin A is present, based on the total of polyolefin A and polymer B. Preferably, the amount of polyolefin is 60-80 wt. %.

The polymer B is composed of vinyl aromatic monomer units and dicarboxylic anhydride monomer units. Suitable vinyl aromatic monomers for use in polymer B are, for example, styrene, alpha-methyl-styrene, para-methylstyrene and mixtures thereof. Styrene is preferably used.

Suitable dicarboxylic anhydrides are, for example, maleic anhydride, chloral maleic anhydride, citraconic anhydride, cyclohexylmaleic anhydride, benzyl maleic anhydride, phenylmaleic anhydride, aconitic anhydride, propylmaleic anhydride and mixtures thereof. Maleic anhydride (MZA) is preferably used.

The polymer B may also contain imide monomer units or spirodilactone units. As imide, N-phenyl-maleimide, maleimide, citraconimide, itaconimide, aconimide, N-methylmaleimide or mixtures thereof can be used in polymer B. The spirodilactone units can be formed by heating the polymer B. The polymer B must continue to contain at least 5% dicarboxylic anhydrides.

The polymer B can be prepared by copolymerizing the vinyl aromatic monomer units and the dicarboxylic anhydride monomer units and / or the imide monomer units in a known manner.

By reacting dicarboxylic anhydride units in polymer B with a primary amine or ammonia, the dicarboxylic anhydride units can be converted into imide units. Examples of amines that can be used are: aniline and methylamine.

The polymer B preferably consists of styrene and maleic anhydride and can contain 5-40 mol% maleic anhydride. In particular, the polymer B contains 22-32 mol% maleic anhydride.

The polymer B is present in the polymer composition in an amount of 5-70% by weight. Preferably 20-40% by weight.

To obtain an even better compatibility, functionalized polyolefin A and / or functionalized polymer B can be added to the polymer composition. To this end, part of the amount of polyolefin A or the amount of polymer B present in the polymer mixture can be replaced by resp. the functionalized polyolefin A or the functionalized polymer B. The part that can be replaced is 0-100%, with a preference for 50-100% for the replacement of polymer B and a preference for 0.5-30% for the replacement of polyolefin A. Combinations of the functionalized polyolefins A and functionalized polymers B can also be used.

Functionalized polyolefin A or polymer B is understood to mean; a polyolefin A or a polymer B containing groups compatible or reactive with polymer B or polyolefin A.

As groups which the functionalized polyolefin A can be mentioned can be mentioned i - an alcohol group, - a thiol group, - an amine group, - an amide group, - an epoxide group, - an oxazoline group, - a isocyanate group or - an alkoxide group.

Preferably, the functional polyolefin A contains one or more isocyanate groups, one or more oxazoline groups or one or more amine groups.

The functionalized polymer B contains as groups one or more functional groups having 10-200 carbon atoms.

The functionalized polyolefin A is synthesized, for example, from a polyolefin A grafted with maleic anhydride or a polyolefin A grafted with acrylic acid. The polyolefin A, grafted with maleic anhydride or acrylic acid, contains 0.01-10% by weight maleic anhydride groups or acrylic acid groups. Preferably, with maleic anhydride or acrylic acid graft, polyolefin A contains 0.1-7 wt% maleic anhydride groups or acrylic acid groups.

The polyolefin A thus grafted with maleic anhydride or acrylic acid is reacted with one or more of the following compounds or combinations of these compounds to obtain the functionalized polyolefin A: - a multi-alcohol, - a multi-thiol, - a multi - amine, - a multi-amide, - a multi-epoxide, - a compound containing 2 or more oxazoline groups, - a compound containing 2 or more isocyanate groups, or - an alkoxide of a metal of group III-VIII of the Periodic System ,

Examples of these compounds are: 1,3-phenylene bisoxazoline, 1,4-phenylene diamine, 1,3-phenylene diamine, methane diphenyl diiosocyanate, tetrabutyl titanate, ethanolamine.

During these reactions, preferably at least 70% maleic anhydride groups or acrylic acid groups are converted without cross-linking of the functionalized polyolefin. Particularly preferably, 100% of the maleic anhydride groups or acrylic acid groups are converted.

For example, the functionalized polymer B is synthesized by seeding the polymer B with a compound having 10-200 carbon atoms and a terminal functional group capable of reacting with the dicarboxylic anhydride groups in the polymer B. Preferably 20-90% of the dicarboxylic anhydride units are converted.

The functionalized polymer B can be grafted with a compound of: - a primary or secondary amine group, - a primary alcohol group, - a primary thiol group, - an oxazoline group, - an epoxide group and / or - an isocyanate group.

For example, these are: 1-dodecylamine, 1-octadecylamine, 1-nonadecyl alcohol, epoxy dodecane, OLOA 1200c from Chevron (an amine-terminated polybutene of approx. * 70 carbon atoms) *

When grafting with an epoxide compound, it is usually necessary to use an activator such as an imidazole, a quaternary ammonium salt or a tertiary amine.

Preferably, a compound of 10-200 carbon atoms and a primary amine functional group is used as a compound to graft polymer B with.

The polymer composition of the invention may also contain an elastomer or an elastomer-containing composition as an impact strength improver. Examples of suitable elastomers or elastomer-containing compositions are; polybutadiene, EPR, EPDM, functionalized EPDM, ABS, AES and silicone elastomer.

0-50% by weight of the elastomer or of the elastomer-containing composition can be added to the polymer composition. 0-30% by weight is preferably added.

The polymer composition can be obtained by mixing all components in any order.

The polymer composition can preferably be obtained by dynamic cross-linking, that is to say mixing and / or kneading during heating in conventional equipment, for example in a Brabender mixer or on rollers or an extruder. The polyolefin A, the polymer B and optionally the compatibilizer are then mixed at a temperature at which all three materials flow well. This temperature is higher than the glass transition temperature of the polymer B and higher than the glass transition temperature or the melting temperature of the polyolefin A, depending on the polyolefin A and the polymer B used.

After the polyolefin A and polymer B are mixed well, the crosslinking compound is added. The time required to conduct the crosslinking reaction varies with compounding conditions (such as temperature and shear rate) and the type of polymer and crosslinker used. Suitable temperatures range from the melting temperature of the polyolefin (175 ° C for polypropylene) to 300 ° C, in particular the limits are 180-260 ° C.

The polymer composition according to the invention may further contain the usual additives, such as fibers, fillers, plasticizers, flame retardants and stabilizers.

The invention is further elucidated by means of the following examples, without being limited thereto.

The Izod is determined according to ISO R180 / 4A (23 ° C; measured parallel to the injection molding direction).

The E modulus is determined according to ISO 178 (23 ° C; measured parallel to the injection molding direction).

Example I

Polypropylene, SMA and crosslinker blends were made on a Berstorff twin screw extruder. Blend conditions: cylinder temperature 215-240 ° C; screw Be 07; speed 150 rpm; yield: 5 kg / h.

As a reference, the same amounts of polypropylene and SMA were mixed without cross-linking added.

The polypropylene used was Stamylan P 83E00r.

The SMA used was Stapron 28110r.

As a cross-linking agent, 1.3 mole% 1,3-phenylene bisoxazoline (PBO) from Takeda Chemicals and 1.5 mole% pentaerythritol (PTA) from Aldrich Chemie were used. The amount of cross-linking agent added is determined relative to the amount of anhydride groups present on polymer B.

Platelets have been made from these mixtures by injection molding. Properties have been measured on these plates.

The results are shown in Table 1.

TABLE 1 without crosslinker PP / SMA Izod Emod (wt.%) (KJ / m2) (N / mm2) 95/5 35.2 1320 90/10 12.4 1350 80/20 5.9 1490 70/30 3, 0 1750

with PBO

95/5 29.1 1300 90/10 21.7 1360 80/20 17.8 1480 70/30 8.5 1680

with PTA

70/30 9.3 1750

It can clearly be seen that adding the crosslinker to the mixture of polypropylene and SMA increases the impact strength, while the stiffness is largely retained compared to the mixture of polypropylene and SMA without a crosslinker.

Comparative example A

Starting from JP-A-63.205.341, blends are made of polypropylene, SMA and a compatibilizer. The polypropylene and the SMA types are the same as those used in Example 1.

The mixtures were made by the same method as in Example 1. The plates were injection molded.

As a compatibilizer are used: A. Kraton G 1652r (a styrene-ethylene-butene-styrene block copolymer) B. Kraton G 1702 Xr (a styrene-ethylene-propylene block copolymer) C. Kraton FG 1901 (a maleic anhydride modified styrene-a-olefin) block copolymer)

The blends consist of: PP / SMA / Kraton 63/27/10 TABLE 2

Kraton izod Emod type kJ / m2 N / mm2 A 3.8 1470 B 4.6 1400 C 3.2 1460

Compared to a cross-linked polypropylene-SMA blend with 70 wt.% Polypropylene and 30 wt.% SMA according to Example 1, the blends with Kraton as a compatibilizer exhibit both poorer impact strength and poorer stiffness.

Example II

Process for the preparation of an α-octadecylamine-modified styrene-maleic anhydride copolymer 150.0 g of Stapron 28110r (SMA) was dissolved in 1 dm3 of methyl ethyl ketone (MEK) under stirring and heating under N2 atmosphere.

Then 28.6 g of α-octadecylamine was added to the solution. The mixture was then heated to 67 ° C with stirring. After the amine was dissolved, the reaction mixture was stirred under N2 for an additional 5 hours at 67 ° C. 2.4 g of sodium acetate and 24 ml of acetic anhydride were then added to the pale yellow, clear reaction mixture, followed by stirring at 80 ° C under N 2 for 5 1/2 hours. After cooling to room temperature, the mixture was coagulated in methanol. The precipitated SMA-g-C 18 H 37 NH 2 was filtered off, washed with methanol and dried under vacuum at 60 ° C. 25% of the original amount of MZA groups had been converted to imide groups (determined by FTIR and elemental analysis).

30% by weight of the SMA-g-C18H37NH2 obtained according to the method described above was mixed with 70% by weight of Stamylan P 4 (PP) under the conditions indicated in Example 1. 1.3 mol% PBO was used as the crosslinker.

TABLE 3 PP / SMA-g-C18H37NH2 Izod Emod (wt%) (kJ / m2) (N / mm2) 70/30 13.1 1650

Compared to a mixture of 70 wt% polypropylene with 30 wt% unmodified SMA cross-linked with PBO, as described in Example 1, the impact resistance is further improved.

Claims (14)

A polymer composition comprising a mixture of a polyolefin A and a polymer B, based on vinyl aromatic and dicarboxylic anhydride monomer units, characterized in that the polymer B is cross-linked. A polymer composition according to claim 1, characterized in that the polymer B is cross-linked with a compound containing at least two functional groups which can react with the dicarboxylic anhydride group of polymer B. A polymer composition according to claim 2, characterized in that the polymer B is cross-linked with a compound containing two or more alcohol groups or two or more thiol groups. A polymer composition according to claim 2, characterized in that the polymer B is cross-linked with a compound containing two or more amine groups or two or more amide groups. A polymer composition according to claim 3 or 4, characterized in that the polymer B is cross-linked with a compound containing one or more alcohol groups and one or more amine groups. A polymer composition according to claim 2, characterized in that the polymer B is cross-linked with a compound containing two or more epoxide groups. A polymer composition according to claim 2, having polymer B cross-linked with a compound containing two or more oxazoline groups. A polymer composition according to claim 2, characterized in that the polymer B is cross-linked with a compound containing two or more isocyanate groups. A polymer composition according to claim 2, characterized in that the polymer B is cross-linked with a salt of a metal atom of group II-VIII of the Periodic System. A polymer composition according to claim 2, characterized in that 0.1-20% by weight of the crosslinker is present. A polymer composition according to claim 2, characterized in that also a compatibilizer is present, consisting of a functionalized polyolefin A and / or a functionalized polymer B. Method for obtaining one or more polymer compositions as described in any one of claims 1-11, characterized in that the polymer composition is dynamically cross-linked. 13. Articles formed in whole or in part from a polymer composition as described in any one of claims 1-11. 14. Polymer composition, method and articles as substantially described and / or further illustrated in the examples.