WO2011117265A1

WO2011117265A1 - Process for producing cling films

Info

Publication number: WO2011117265A1
Application number: PCT/EP2011/054386
Authority: WO
Inventors: Liqun Ren; Gabriel Skupin
Original assignee: Basf Se
Priority date: 2010-03-24
Filing date: 2011-03-23
Publication date: 2011-09-29
Also published as: EP2550330A1; CN102869723A; AU2011231669A1; KR20130010080A; CA2792845A1

Abstract

The present invention relates to a process for producing cling films, using biodegradable polyesters obtainable by polycondensation of: i) 65 to 80 mol%, based on the components i to ii, one or more dicarboxylic acid derivatives or dicarboxylic acids selected from the group consisting of: succinic acid, adipic acid, sebacic acid, azelaic acid and brassylic acid; ii) 35 to 20 mol%, based on the components i) to ii), of a terephthalic acid derivative; iii) 98 to 102 mol%, based on the components i) to ii), of a C2-C8 alkylenediol or C2-C6 oxyalkylenediol; iv) 0.1 to 2% by weight, based on the polymer obtainable from the components i to iii, of an at least trifunctional crosslinker or at least difunctional chain extender. In addition the invention relates to polymer mixtures which are particularly suitable for producing cling films, and to cling films which contain biodegradable polyesters.

Description

Process for the production of cling foils

The present invention relates to a process for the production of cling foils using biodegradable polyesters obtainable by polycondensation of:

65 to 80 mol%, based on the components i to ii, of one or more dicarboxylic acid derivatives or dicarboxylic acids selected from the group consisting of: succinic acid, adipic acid, sebacic acid, azelaic acid and hydrosilicic acid;

35 to 20 mol%, based on the components i to ii, of a terephthalic acid derivative;

98 to 102 mol%, based on the components i to ii, of a C2-C8-alkylenediol or C2-C6-oxyalkylenediol;

0.1 to 2% by weight, based on the polymer obtainable from components i to iii, of an at least trifunctional crosslinker or at least difunctional chain extender.

Furthermore, the invention relates to a process for the preparation of cling foils using the polymer components a) and b):

5 to 95 wt .-% of a biodegradable polyester according to claim 1 and

From 95 to 5% by weight of an aliphatic-aromatic polyester obtainable by polycondensation of:

40 to 60 mol%, based on the components i to ii, of one or more dicarboxylic acid derivatives or dicarboxylic acids selected from the group consisting of: succinic acid, adipic acid, sebacic acid, azelaic acid and brassylic acid;

60 to 40 mol%, based on the components i to ii, of a Terephthalsäu rederivats; iii) 98 to 102 mol%, based on the components i to ii, of a C 2 -C 8 -alkylenediol or C 2 -C 6 -oxyalkylenediol iv) 0 to 2 wt .-%, based on the polymer obtainable from the components i to iii, of an at least trifunctional crosslinker or difunctional Ketten tenverlängerers. Moreover, the invention relates to a process for the production of cling foils using the polymer components a), b) and c): a) 10 to 40 wt .-% of a biodegradable polyester according to claim 1 and

b) from 89 to 46% by weight of an aliphatic-aromatic polyester obtainable by polycondensation of: i) 40 to 70 mol%, based on components i to ii, of one or more dicarboxylic acid derivatives or dicarboxylic acids selected from the group consisting of: Succinic, adipic, sebacic, azelaic and brassylic acids; ii) 60 to 30 mol%, based on the components i to ii, of a terephthalic acid derivative; iii) 98 to 102 mol%, based on components i to ii, of a C 2 -C 8 -alkylenediol or C 2 -C 6 -oxyalkylenediol; iv) 0 to 2% by weight, based on the polymer obtainable from components i to iii, of an at least trifunctional crosslinker or difunctional chain extender;

1 to 14 wt .-%, one or more polymers selected from the group consisting of: polylactic acid, polycaprolactone, polyhydroxyalkanoate, polyalkylene lencarbonat, chitosan and gluten and one or more polyesters based on aliphatic diols and aliphatic dicarboxylic - and

0 to 2 wt .-% of a compatibilizer. WO-A 92/09654 describes linear aliphatic-aromatic polyesters which are biodegradable. Crosslinked, biodegradable polyesters are described in WO-A 96/15173. The polyesters described have a higher terephthalic acid content and can not always convince with regard to their film properties - in particular their elastic behavior, which is of great importance for cling film. The aim of the present invention was therefore to provide a process for the production of cling foils.

The polyesters described at the outset, which have a narrowly defined terephthalic acid content and a narrowly defined content of crosslinking agent, are surprisingly very suitable for cling film.

Preference is given to biodegradable polyesters having the following constituents: Components i) is preferably adipic acid and / or sebacic acid. Component iii), the diol, is preferably 1,4-butanediol. Component iv), the crosslinker, is preferably glycerol.

The synthesis of the polyesters described is generally carried out in a two-stage reaction cascade (see WO09 / 127555 and WO09 / 127556). First, the dicarboxylic acid derivatives, as in the synthesis examples, are reacted together with the diol (for example 1,4-butanediol) in the presence of a transesterification catalyst to give a prepolyester. This prepolyester generally has a viscosity number (CV) of 50 to 100 ml / g, preferably 60 to 90 ml / g. The catalysts used are usually zinc, aluminum and in particular titanium catalysts. Titanium catalysts such as tetra (isopropyl) orthotitanate and in particular tetrabutyl orthotitanate (TBOT) have the advantage over the tin, antimony, cobalt and lead catalysts commonly used in the literature, such as tin dioctanoate, that residual amounts of the catalyst or secondary product of the catalyst remaining in the product are less toxic are.

The polyesters according to the invention are optionally subsequently chain-extended according to the processes described in WO 96/15173 and EP-A 488 617. The prepolyester is reacted, for example, with chain extenders vib), as with diisocyanates or with epoxy-containing polymethacrylates, in a chain extension reaction to give a polyester having a viscosity of 60 to 450 ml / g, preferably 80 to 250 ml / g. A mixture of the dicarboxylic acids is initially condensed in the presence of an excess of diol together with the catalyst initially. Subsequently, the melt of the prepolyester thus obtained is usually at an internal temperature of 200 to 250 ° C within 3 to 6 hours at reduced pressure while distilling off diols to the desired viscosity with a viscosity number (VZ) of 60 to 450 mL / g and preferably 80 to 250 mL / g condensed. Particular preference is given to the polyesters of the invention according to the in

WO09 / 127556 described continuous process. The abovementioned ranges of viscosity numbers merely serve as indications for preferred process variants, but are not intended to be limiting for the present application subject.

In addition to the continuous process described above, the polyesters according to the invention can also be prepared in a batch process. For this purpose, the aliphatic and the aromatic dicarboxylic acid derivative, the diol and a branching agent are mixed in any metering order and condensed to form a prepolyester. Optionally, with the aid of a chain extender, a polyester can be adjusted with the desired viscosity number.

Examples of polybutylene terephthalate succinates, azelates, brassates and, in particular, adipates and sebacates having an acid number, measured in accordance with DIN EN 12634, of less than 1.0 mg KOH / g and a viscosity number greater than 130 ml / g can be obtained by the abovementioned processes and a MVR according to ISO 1133 of less than 6 cm ^3/10 min (190 ° C, 2.16 kg weight). These products are particularly interesting for film applications.

Sebacic acid, azelaic acid and brassylic acid (i) are derived from renewable resources, in particular from vegetable oils such as e.g. Castor oil accessible.

The terephthalic acid ii is used in 20 to 35 mol%, based on the acid components i and ii.

Terephthalic acid and the aliphatic dicarboxylic acid can be used either as the free acid or in the form of ester-forming derivatives. Particularly suitable ester-forming derivatives are the di-C 1 - to C 6 -alkyl esters, such as dimethyl, diethyl, di-n-propyl, diisopropyl, di-n-butyl, diisobutyl, di-t-butyl, Di-n-pentyl, di-iso-pentyl or di-n-hexyl esters to name. Anhydrides of dicarboxylic acids can also be used.

The dicarboxylic acids or their ester-forming derivatives can be used individually or as a mixture.

1, 4-butanediol is also available from renewable raw materials. WHERE

09/024294 discloses a biotechnological process for the production of 1,4-butanediol from different carbohydrates with microorganisms from the class of Pasteurellaceae. As a rule, at the beginning of the polymerization, the diol (component iii) is added to the acids (components i and ii) in a ratio of diol to diacids of from 1.0 to 2.5: 1 and preferably from 1.3 to 2.2: l set. Excess diol quantities are withdrawn during the polymerization, so that at the end of the polymerization an approximately equimolar ratio is established. By approximately equimolar is meant a diol / diacid ratio of 0.98 to 1.02: 1.

The said polyesters may have hydroxyl and / or carboxyl end groups in any ratio. The abovementioned partially aromatic polyesters can also be end-group-modified. Thus, for example, OH end groups can be acid-modified by reaction with phthalic acid, phthalic anhydride, trimellitic acid, trimellitic anhydride, pyromellitic acid or pyromellitic anhydride. Preference is given to polyesters having acid numbers of less than 1.5 mg KOH / g. As a rule, a crosslinker iva and optionally additionally a chain extender ivb selected from the group consisting of: a polyfunctional isocyanate, isocyanurate, oxazoline, epoxide, carboxylic anhydride, an at least trifunctional alcohol or an at least trifunctional carboxylic acid are used. Suitable chain extenders ivb are polyfunctional and in particular difunctional isocyanates, isocyanurates, oxazolines, carboxylic anhydride or epoxides. The crosslinkers iva) are generally in a concentration of 0.1 to 2 wt .-%, preferably 0.2 to 1, 5 wt .-% and particularly preferably 0.3 to 1 wt .-% based on the polymer available from components i to iii used. The chain extenders ivb) are generally used in a concentration of 0.01 to 2 wt .-%, preferably 0.1 to 1 wt .-% and particularly preferably 0.35 to 2 wt .-% based on the total weight of the components i used to iii.

Chain extenders and alcohols or carboxylic acid derivatives having at least three functional groups can also be understood as crosslinkers. Particularly preferred compounds have three to six functional groups. Examples include: tartaric acid, citric acid, malic acid; Trimethylolpropane, trimethylolethane; pentaerythritol; Polyether triols and glycerol, trimesic acid, trimellitic acid, trimellitic anhydride, pyromellitic acid and pyromellitic dianhydride. Preference is given to polyols such as trimethylolpropane, pentaerythritol and in particular glycerol. By means of components iv, biodegradable polyesters with a structural viscosity can be built up. The rheological behavior of the melts improves; The biodegradable polyesters are easier to process, for example, better by melt consolidation to remove films. The compounds iv are shear-thinning, i. the viscosity under load becomes lower.

In general, it is useful to add the crosslinking (at least trifunctional) compounds at an earlier stage of the polymerization. Suitable bifunctional chain extenders are aromatic diisocyanates and in particular aliphatic diisocyanates, especially linear or branched alkylene diisocyanates or cycloalkylene diisocyanates having 2 to 20 carbon atoms, preferably 3 to 12 carbon atoms, eg 1, 6-hexa-methylene diisocyanate, isophorone diisocyanate or methylene bis (4- isocyanatocyclo-hexane). Particularly preferred aliphatic diisocyanates are isophorone diisocyanate and in particular 1,6-hexamethylene diisocyanate.

The polyesters of the invention generally have a number average molecular weight (Mn) in the range from 5000 to 100,000, in particular in the range from 10,000 to 60,000 g / mol, preferably in the range from 15,000 to 38,000 g / mol, a weight-average molecular weight (Mw) from 30,000 to 300,000, preferably 60,000 to 200,000 g / mol, and a Mw / Mn ratio of 1 to 15, preferably 2 to 8. The viscosity number is between 30 and 450, preferably from 50 to 400 ml / g and in particular preferably from 80 to 250 ml / g (measured in o-dichlorobenzene / phenol (weight ratio 50/50)). The melting point is in the range of 85 to 150, preferably in the range of 95 to 140 ° C.

In a preferred embodiment, from 1 to 80% by weight, based on the total weight of components i to iv, of an organic filler is selected from the group consisting of: native or plasticized starch, natural fibers, wood flour, comminuted cork, ground bark, Nutshells, ground press cakes (vegetable oil refinery), dried production residues from the fermentation or distillation of beverages such as Beer, brewed sodas (eg bionade), wine or sake and / or an inorganic filler selected from the group consisting of: chalk, graphite, gypsum, carbon black, iron oxide, calcium chloride, dolomite, kaolin, silicon dioxide (quartz), sodium carbonate, titanium dioxide, Silicate, wollastonite, mica, montmorillonite, talc, glass fibers and mineral fibers added. Starch and amylose may be native, i. not thermoplasticized or thermoplasticized with plasticizers such as glycerol or sorbitol (EP-A 539 541, EP-A 575 349, EP 652 910).

Among natural fibers are, for example, cellulose fibers, hemp fibers, sisal, kenaf, Jute, Flax, Abacca, coconut fiber or regenerated cellulose fibers (rayon) such. B. Cordenkafasern understood.

Preferred fibrous fillers are glass fibers, carbon fibers, aramid fibers, potassium titanate fibers and natural fibers, glass fibers being particularly preferred as E glass. These can be used as rovings or in particular as chopped glass in the commercial forms. These fibers generally have a diameter of 3 to 30μηη, preferably 6 to 20μηη and special preferably from 8 to 15μηι on. The fiber length in the compound is generally 20μηη to Ι ΟΟΟμηη, preferably 180 to 500μηη and more preferably 200 to 400 μπι. The fibrous fillers can be surface-pretreated for better compatibility with the thermoplastic, for example with a silane compound.

The biodegradable polyester or polyester mixtures may contain further ingredients known to the person skilled in the art but not essential to the invention. For example, the customary in plastics technology additives such as stabilizers;

nucleating agents; Neutralizing agents; Lubricants and release agents such as stearates (especially calcium stearate); Plasticizers such as citric acid esters (especially acetyl tributyl citrate), glyceric acid esters such as triacetylglycerol or ethylene glycol derivatives, surfactants such as polysorbates, palmitates or laurates; Waxes such as beeswax or beeswax esters; Antistatic, UV absorber; UV-stabilizer; Antifog agents or dyes. The additives are used in concentrations of 0 to 5 wt .-%, in particular 0.1 to 2 wt .-% based on the polyesters of the invention. Plasticizers may be present in 0.1 to 10% by weight in the polyesters of the invention.

The biodegradable polyesters of claim 1 are often tacky. In order to accomplish their processing into films without problems, it is advisable, if the polyesters are to be used without further mixing partners, to add additives such as, in particular, lubricants and release agents.

As lubricants or mold release agents (component e) are in particular hydrocarbons, fatty alcohols, higher carboxylic acids, metal salts of higher carboxylic acids such as calcium or zinc stearate, fatty acid amides such as erucic acid amide and wax types, z. As paraffin waxes, beeswax or montan waxes proven. Preferred lubricants are erucic acid amide and / or wax types, and more preferably combinations of these lubricants. Preferred types of wax are beeswax and Esterwachse, in particular glycerol monostearate or dimethylsiloxane or polydimethylsiloxane such as Belsil ^® DM Fa. Wacker. The component e is usually added in 0.05 to 5.0 wt .-% and preferably 0.1 to 2.0 wt .-% based on the biodegradable polyester.

A preferred formulation of the biodegradable polyester comprises: a) 99.9 to 98% by weight of an aliphatic-aromatic polyester obtainable by polycondensation of: 65 to 80 mol%, based on the components i to ii, of one or more dicarboxylic acid derivatives or dicarboxylic acids selected from the group consisting of: succinic acid, adipic acid, sebacic acid, azelaic acid and brassylic acid;

35 to 20 mol%, based on the components i to ii, of a Terephthalsäu rederivats; iii) 98 to 102 mol%, based on the components i to ii, of a C2-C8-

Alkylenediols or C 2 -C 6 -oxyalkylenediols; iv) from 0.1 to 2% by weight, based on the polymer obtainable from components i to iii, of an at least trifunctional crosslinker or at least difunctional chain extender and

0.1 to 2 wt .-% of a lubricant or release agent.

Preference is furthermore Clingfolien containing the aforementioned formulations.

The preparation of the abovementioned formulations and biodegradable polyester mixtures according to the invention from the individual components can be carried out by known processes (EP 792 309 and US Pat. No. 5,883,199). For example, all mixing partners can be mixed and reacted in a process step in mixing apparatus known to the person skilled in the art, for example kneaders or extruders, at elevated temperatures, for example from 120 ° C. to 250 ° C.

Typical polyester mixtures for cling film preparation contain: a) 5 to 95% by weight, preferably 10 to 40% by weight and particularly preferably 25 to 35% by weight of a biodegradable polyester according to Claim 1 and b) 95 to 50% by weight. %, preferably 90 to 60 wt .-% and particularly preferably 75 to 65 wt .-% of an aliphatic-aromatic polyester obtainable by polycondensation of: i) 40 to 60 mol%, based on the components i to ii, of one or a plurality of dicarboxylic acid derivatives or dicarboxylic acids selected from the group consisting of: succinic acid, adipic acid, sebacic acid, azelaic acid and brassylic acid; ii) 60 to 40 mol%, based on the components i to ii, of a terephthalic acid derivative; iii) 98 to 102 mol%, based on components i to ii, of a C 2 -C 8 -alkylenediol or C 2 -C 6 -oxyalkylenediol; iv) 0 to 2 wt .-%, based on the polymer obtainable from the components i to iii, of an at least trifunctional crosslinker or difunctional Ketten tenverlängerers.

Furthermore, the following polymer mixtures are suitable for the production of cling foils: a) 10 to 40% by weight, preferably 20 to 30% by weight, of a biodegradable polyester according to claim 1 and

b) from 89 to 46% by weight, preferably from 79 to 60% by weight, of an aliphatic-aromatic polyester obtainable by polycondensation of:

40 to 70 mol%, based on the components i to ii, of one or more dicarboxylic acid derivatives or dicarboxylic acids selected from the group consisting of: succinic acid, adipic acid, sebacic acid, azelaic acid and brassylic acid;

60 to 30 mol%, based on the components i to ii, of a Terephthalsäu rederivats; v) 98 to 102 mol%, based on the components i to ii, of a C2-C8-

Alkylenediols or C 2 -C 6 -oxyalkylenediols; vi) 0 to 2 wt .-%, based on the polymer obtainable from the components to iii, of an at least trifunctional crosslinker or difunctional Ketten tenverlängerers;

1 to 14 wt .-%, preferably 1 to 10 wt .-% of one or more polymers selected from the group consisting of: polylactic acid, polycaprolactone, polyhydroxyalkanoate, polyalkylene carbonate, chitosan and gluten and one or more polyesters based on aliphatic diols and aliphatic Dicarboxylic acids - and

0 to 2 wt .-% of a compatibilizer. The aforementioned polyester mixtures comprising the components a) and b) or a), b) and c) are suitable as Clingfolien due to their excellent recovery behavior. The polymer mixtures in turn preferably contain from 0.05 to 2% by weight of a compatibilizer. Preferred compatibilizers are carboxylic acid anhydrides, such as maleic anhydride, and in particular the previously described epoxide group-containing copolymers based on styrene, acrylic esters and / or methacrylic acid esters. The epoxy groups bearing units are preferably glycidyl (meth) acrylates. The epoxy-containing copolymers of the above type are sold for example by BASF Resins BV under the trademark Joncryl ^® ADR. Is particularly suitable as compatibilizers, for example, Joncryl ADR ^® 4368. As a biodegradable polyester (component b) is suitable, for example, re Polymilchsäu-. Polylactic acid having the following property profile is preferably used:

A melt volume rate (MVR at 190 ° C. and 2.16 kg according to ISO 1 133 of 0.5 to 30, preferably 2 to 18 ml / 10 minutes)

· A melting point below 240 ° C;

• a glass point (Tg) greater than 55 ° C

• a water content of less than 1000 ppm

• a residual monomer content (lactide) of less than 0.3%.

• a molecular weight greater than 80,000 daltons.

Preferred polylactic acids are, for example, NatureWorks® 3001, 3051, 3251, 4020, 4032 or 4042D (polylactic acid from NatureWorks or NL-Naarden and USA Blair / Nebraska). Polyhydroxyalkanoates are understood as meaning primarily poly-4-hydroxybutyrates and poly-3-hydroxybutyrates, furthermore copolyesters of the abovementioned hydroxybutyrates with 3-hydroxyvalerates or 3-hydroxyhexanoate are included. Poly-3-hydroxybutyrate-co-4-hydroxybutyrates are known in particular from Metabolix. They are sold under the trade name Mirel®. Poly-3-hydroxybutyrate-co-3-hydroxyhexanoates are known from the company P & G or Kaneka. Poly-3-hydroxybutyrates are sold, for example, by PHB Industrial under the brand name Biocycle® and by Tianan under the name Enmat®.

The polyhydroxyalkanoates generally have a molecular weight Mw of from 100,000 to 1,000,000, and preferably from 300,000 to 600,000.

Polycaprolactone is marketed by the company. Daicel under the product names Placcel ^®.

Polyalkylene carbonates are understood as meaning, in particular, polyethylene carbonate and polypropylene propylene carbonate. Partly aromatic (aliphatic-aromatic) polyesters based on aliphatic diols and aliphatic / aromatic dicarboxylic acids (component c) are also understood to mean polyester derivatives such as polyether esters, polyester amides or polyetherresteramides. Suitable partially aromatic polyesters include linear non-chain-extended polyesters (WO 92/09654). In particular, aliphatic / aromatic polyesters of butanediol, terephthalic acid and aliphatic C6-Ci8 dicarboxylic acids such as adipic acid, suberic acid, azelaic acid, sebacic acid and brassylic acid (for example as described in WO 2006/097353 to 56) suitable mixing partners. Preferred are chain-extended and / or branched partially aromatic polyesters. The latter are known from the aforementioned documents WO 96/15173 to 15176, 21689 to 21692, 25446, 25448 or WO 98/12242, to which reference is expressly made. Mixtures of different partially aromatic polyesters are also possible. In particular (Novamont) are partially aromatic polyesters products such as Ecoflex ^® (BASF SE), Eastar ^® Bio and Origo-Bi ^® to understand. They have a higher terephthalic acid content (aromatic dicarboxylic acid) than the biodegradable polyesters of claim 1.

For the purposes of the present invention, the feature "biodegradable" for a substance or a substance mixture is fulfilled if this substance or the substance mixture according to DIN EN 13432 has a percentage degree of biodegradation of at least 90%.

In general, biodegradability causes the polyester blends to disintegrate in a reasonable and detectable time. Degradation can be effected enzymatically, hydrolytically, oxidatively and / or by the action of electromagnetic radiation, for example UV radiation, and is usually effected for the most part by the action of microorganisms such as bacteria, yeasts, fungi and algae. The biodegradability can be quantified, for example, by mixing polyesters with compost and storing them for a certain period of time. For example, according to DIN EN 13432 (referring to ISO 14855), C02-free air is allowed to flow through matured compost during composting and subjected to a defined temperature program. Here, the biodegradability is determined by the ratio of the net CO 2 release of the sample (after subtraction of CO 2 release by the compost without sample) to the maximum CO 2 release of the sample (calculated from the carbon content of the sample) as a percentage of the CO 2 release defined biodegradation. Biodegradable polyesters (mixtures) generally show signs of decomposition after only a few days of composting, such as fungal growth, cracking and hole formation. Other methods of determining biodegradability are described, for example, in ASTM D 5338 and ASTM D 6400-4. The Clingfolien (cling film) are generally produced in the thickness range of 10 to 25 μηη. The usual manufacturing process is the tubular film extrusion in a monolayer film. In addition, chill-roll extrusion has also established itself as a process for coextruded cling films.

The cling foils hitherto on the market consist mainly of PVC, plasticizers (e.g., 20-30% dioctyl phthalate), and anti-fog additives which prevent the film from fogging during temperature cycling. In addition, cling foils based on LDPE have prevailed, but they require a clinging additive (polyisobutylene). Cling foils made of PE also contain anti-fog additives.

A specific version of the cling foil contains a styrene / butadiene copolymer (styroflex), which has excellent recovery on deformation. These films are produced in 3 layers. The outer layers contain an ethylenevinyl acetate, which is equipped with antifogging additives. The middle layer contains the styrene / butadiene copolymer which provides strength, extensibility and resilience. Cling foils are used for the packaging of fruits and vegetables as well as fresh meat, bones and fish. You have the following requirement profile:

1 . Extrudability on specific tubular film systems:

a. Bubble stability at 10 μηη

b. MFR (190 ° C, 2.16 kg) in the range of 0.3 to 4 g / 10 min.

2. Transparency

3. Recovery after deformation (hysteresis)

4. Strength for non-slip packaging of the contents

5. puncture resistance

6. Cuttability transverse to the extrusion direction

7. Antifog effect between room temperature and 0 ° C in the cold store

8. Weldability on the packing machine or handpacking

The traditional PVC film serves as a comparison:

Films of biodegradable polyester according to claim 1 have good film properties and can be very good to 10 μηη undress. The mechanical properties such as longitudinal and transverse strength for extrusion and puncture resistance are at a high level.

Tubular films made from these polyesters show a highly elastomeric behavior. They achieve higher strengths than PVC before the film breaks. Therefore, one is Modification of the stiffness-toughness ratio by the use of branching agents and the reduction of the terephthalic acid content for Clingfolien useful. Cling foils made from these polyesters can also be equipped with anti-fog additives. The transparency of these cling foils is sufficient for most applications. However, they are not quite as transparent as PVC and therefore distinguishable from traditional PVC.

In particular, the Clingfolien invention impressed by the improved hysteresis (resilience of deformations).

The cling foils of the present invention are also easier to cut without tearing longitudinally to the direction of extrusion, since with lower terephthalic acid content and increased branching, the strong anisotropy of the film is reduced. The weldability of the cling foils of the invention is at a similar level as PVC or PE.

Application Measurements: The molecular weights Mn and Mw of the semiaromatic polyesters were determined in accordance with DIN 55672-1 eluent hexafluoroisopropanol (HFIP) + 0.05% by weight of trifluoroacetic acid potassium salt; The calibration was carried out with narrowly distributed polymethyl methacrylate standards. The determination of the viscosity numbers was carried out according to DIN 53728 Part 3, January 3, 1985, capillary viscometry. A micro Ubbelohde viscometer, type M-II was used. The solvent used was the mixture: phenol / o-dichlorobenzene in a weight ratio of 50/50.

The hysteresis test was carried out on 60 μηη thick films according to DIN 53835 at 23 ° C. The film was first loaded at 120 mm / min. After reaching the 50% elongation was relieved without holding time again. Then was waited for 5 minutes. This was followed by the second cycle with 100% stretch in the top.

The degradation rates of the biodegradable polyester blends and the blends prepared for comparison were determined as follows:

From the biodegradable polyester mixtures and the blends prepared for comparison, films having a thickness of 30 μm were produced by pressing at 190 ° C. These films were each cut into square pieces with edge lengths of 2 x 5 cm. The weight of these pieces of film was determined in each case and defined as "100% by weight." Over a period of four weeks, the pieces of film were heated to 58 ° C. in a drying box in a plastic can filled with humidified compost remain- Bending weight of the film pieces measured and converted to wt .-% (based on the determined at the beginning of the test and defined as "100 wt .-%" weight).

feedstocks

Polyester A1

a polybutylene terephthalate adipate prepared as follows: 1, 10.1 g of dimethyl terephthalate (27 mol%), 224 g of adipic acid (73 mol%), 246 g of 1,4-butanediol (130 mol%) and 0.34 ml of glycerol (0.1% by weight based on the polymer) were mixed together with 0.37 ml of tetrabutyl orthotitanate (TBOT), the molar ratio between alcohol components and acid component being 1.30. The reaction mixture was heated to a temperature of 210 ° C and held at this temperature for 2 hours. Subsequently, the temperature was raised to 240 ° C and gradually evacuated. The excess dihydroxy compound was distilled off under a vacuum of less than 1 mbar over a period of 3 h. The polyester A1 thus obtained had a melting point of 60 ° C and a VZ of 156 ml / g.

Polyester A2

a polybutylene terephthalate adipate prepared as follows: 583.3 g of dimethyl terephthalate (27 mol%), 1280.2 g of adipic acid (73 mol%), 1405.9 g of 1,4-butanediol (130 mol%) and 37 g Glycerol (1, 5 wt .-% based on the polymer) were mixed together with 1 g of tetrabutyl orthotitanate (TBOT), wherein the molar ratio between alcohol components and acid component was 1.30. The reaction mixture was heated to a temperature of 210 ° C and held at this temperature for 2 hours. Subsequently, the temperature was raised to 240 ° C and gradually evacuated. The excess dihydroxy compound was distilled off under a vacuum of less than 1 mbar over a period of 2 h. The polyester A2 thus obtained had a melting point of 60 ° C and a VZ of 146 ml / g. Polyester A3

a polybutylene terephthalate adipate prepared as follows: 697.7 g of terephthalic acid (35 mol%), 1 139.9 g of adipic acid (65 mol%), 1405.9 g of 1,4-butanediol

(130 mol%) and 37.3 ml of glycerol (1, 5 wt .-% based on the polymer) were mixed together with 2.12 ml of tetrabutyl orthotitanate (TBOT), wherein the molar ratio between alcohol components and acid component was 1.30. The reaction mixture was heated to a temperature of 210 ° C and held at this temperature for 2 hours. Subsequently, the temperature was raised to 240 ° C and gradually evacuated. The excess dihydroxy compound was distilled off under a vacuum of less than 1 mbar over a period of 2 h. The resulting polyester A3 had a melting point of 80 ° C (broad) and a VZ of 191 ml / g. Polyester A4

a polybutylene terephthalate adipate prepared as follows: 726.8 g of terephthalic acid (35 mol%), 1 187.4 g of adipic acid (65 mol%), 1464.5 g of 1,4-butanediol

(130 mol%) and 372.06 ml of glycerol (0.1% by weight based on the polymer) were mixed together with 2.21 ml of tetrabutyl orthotitanate (TBOT), the molar ratio between alcohol components and acid component being 1.30. The reaction mixture was heated to a temperature of 210 ° C and held at this temperature for 2 hours. Subsequently, the temperature was raised to 240 ° C and gradually evacuated. The excess dihydroxy compound was distilled off under a vacuum of less than 1 mbar over a period of 3 h. The polyester A4 thus obtained had a melting point of 80 ° C and a VZ of 157 ml / g.

Polyester B1

a polybutylene terephthalate adipate prepared as follows: 87.3 kg of dimethyl terephthalate (44 mol%), 80.3 kg of adipic acid (56 mol%), 17 g of 1, 4-butanediol and 0.2 kg of glycerol (0, 1% by weight based on the polymer) were mixed together with 0.028 kg of tetrabutyl orthotitanate (TBOT), the molar ratio between alcohol components and acid component being 1.30. The reaction mixture was heated to a temperature of 180 ° C and reacted at this temperature for 6 hours. Subsequently, the temperature was raised to 240 ° C and the excess dihydroxy compound distilled off under vacuum over a period of 3h. Subsequently, 0.9 kg of hexamethylene diisocyanate were metered in slowly within 1 h at 240 ° C. The polyester B1 thus obtained had a melting temperature of 1 19 ° C and a molecular weight (M _n ) of 23000 g / mol, molecular weight (M _w ) of 13000 g / mol.

Polyester C1

Polylactic acid from NatureWorks 4042D® Compatibilizer D1

Joncryl ADR 4368CS

Examples: The polyesters A1, A3, A4 and Comparative Example B1 were hot presses to the press foils FA1; FA3, FA4 and comparative film FB1 processed and subjected to a hysteresis test.

Production of press foils

2.5g polyester was distributed in the frame (60μηη, 20x20cm). The frames were placed in the press. Subsequently, the polymer was produced at a temperature of 160.degree. heat and at this temperature 10min. Thereafter, the press plates were applied to the polymer films and gradually pressed to 200 bar. After 2 minutes, the press plates were cooled to RT and relaxed. hysteresis

The hysteresis test was carried out on 60 m thick films according to DIN 53835 at 23 ° C. First the slides were cut to 4mm ^* 25mm. Such film was then loaded at 120 mm / min. After reaching the 50% elongation, the film was relieved without holding time (first measurement of the resilience). Then it waited 6 minutes. This was followed by the second cycle with the 100% stretch in the top.

The measurements show that the films, which consist of a polyester with a low terephthalic acid content such as, for example, FA1, had a higher restoring force than the comparison film FB1. A further increase in the restoring force experienced films with a high crosslinking agent content (FA3 compared to FA4).

Claims

claims

A process for producing cling films using biodegradable polyesters obtainable by polycondensation of: i) 65 to 80 mol%, based on components i to ii, of one or more dicarboxylic acid derivatives or dicarboxylic acids selected from the group consisting of: succinic acid, adipic acid, sebacic acid Azelaic and brassylic acids; ii) 35 to 20 mol%, based on the components i to ii, of a terephthalic acid derivative; iii) 98 to 102 mol%, based on components i to ii, of a C 2 -C 8 -alkylenediol or C 2 -C 6 -oxyalkylenediol; iv) from 0.1 to 2% by weight, based on the polymer obtainable from components i to iii, of an at least trifunctional crosslinker or difunctional chain extender.

The process of claim 1 wherein the crosslinker (component iv) in the biodegradable polyester is glycerol.

A process as claimed in claim 1, wherein adipic acid and / or sebacic acid is used as the dicarboxylic acid (component i).

Process for the preparation of cling foils using the polymer components a) and b):

a) 5 to 95 wt .-% of a biodegradable polyester according to claim 1 and

b) from 95 to 5% by weight of an aliphatic-aromatic polyester obtainable by polycondensation of: i) 40 to 60 mol%, based on components i to ii, of one or more dicarboxylic acid derivatives or dicarboxylic acids selected from the group consisting of: succinic acid, Adipic acid, sebacic acid, azelaic acid and brassylic acid; ii) 60 to 40 mol%, based on the components i to ii, of a terephthalic acid derivative; iii) 98 to 102 mol%, based on the components i to ii, of a C 2 -C 8 -alkylenediol or C 2 -C 6 -oxyalkylenediol

0 to 2 wt .-%, based on the polymer obtainable from the components i to iii, of an at least trifunctional crosslinker or di-functional chain extender.

Process for the preparation of cling foils using the polymer components a), b) and c):

a) 10 to 40 wt .-% of a biodegradable polyester according to claim 1 and

b) from 89 to 46% by weight of an aliphatic-aromatic polyester obtainable by polycondensation of:

From 40 to 70 mol%, based on the components i to ii, of one or more dicarboxylic acid derivatives or dicarboxylic acids selected from the group consisting of succinic acid, adipic acid, sebacic acid, azelaic acid and brassylic acid;

60 to 30 mol%, based on the components i to ii, of a terephthalsäurederivats;

0 to 2 wt .-%, based on the polymer obtainable from the components i to iii, of an at least trifunctional crosslinker or di-functional chain extender; c) 1 to 14 wt .-%, one or more polymers selected from the group consisting of: polylactic acid, polycaprolactone, polyhydroxyalkanoate, polyalkylene carbonate, chitosan and gluten and one or more polyesters based on aliphatic diols and aliphatic dicarboxylic - and

0 to 2 wt .-% of a compatibilizer.

6. The method according to claims 4 and 5, wherein for the preparation of the films mixtures containing the polymer components a) and b) or the polymer components a), b) and c) are used.

7. The method of claim 6, wherein the mixtures contain 0.05 to 2 wt .-% of an epoxy-containing poly (meth) acrylate as a compatibilizer.

8. The method of claim 4 and 5, wherein multilayer films are prepared by coextrusion, wherein at least the middle and / or inner layer of the film contains a biodegradable polyester according to claim 1.

9. The method according to any one of claims 4 to 8, wherein the component c) is polylactic acid.

10. Polymer blends comprising: a) 5 to 95 wt .-% of a biodegradable polyester obtainable by polycondensation of: i) 65 to 80 mol%, based on the components i to ii, of one or more dicarboxylic acid derivatives or dicarboxylic acids selected from the group consisting from: succinic acid, adipic acid, sebacic acid, azelaic acid and brassylic acid; ii) from 35 to 20 mol%, based on components i to ii, of a terephthalic acid derivative; iii) 98 to 102 mol%, based on the components i to ii, of a C2-C8-

Alkylenediols or C 2 -C 6 -oxyalkylenediols; iv) from 0.1 to 2% by weight, based on the polymer obtainable from components i to iii, of an at least trifunctional crosslinker or difunctional chain extender; b) from 95 to 5% by weight of an aliphatic-aromatic polyester obtainable by polycondensation of: i) 40 to 60 mol%, based on components i to ii, of one or more dicarboxylic acid derivatives or dicarboxylic acids selected from the group consisting of: succinic acid, Adipic acid, sebacic acid, azelaic acid and brassylic acid;

60 to 40 mol%, based on the components i to ii, of a rephthalsäurederivats; 98 to 102 mol%, based on components i to ii, of a C 2 -C 8 -alkylenediol or C 2 -C 6 -oxyalkylenediol;

0 to 2 wt .-%, based on the polymer obtainable from the compo nents i to iii, an at least trifunctional crosslinker or di-functional chain extender. Polymer blends containing: a) 10 to 40 wt .-% of a biodegradable polyester containing: i) 65 to 80 mol%, based on the components i to ii, of one or more dicarboxylic acid derivatives or dicarboxylic acids selected from the group consisting of: succinic acid, adipic acid Sebacic acid, azelaic acid and brassylic acid; ii) from 35 to 20 mol%, based on components i to ii, of a terephthalic acid derivative; iii) 98 to 102 mol%, based on the components i to ii, of a C2-C8

Alkylenediols or C 2 -C 6 -oxyalkylenediols; iv) from 0.1 to 2% by weight, based on the polymer obtainable from components i to iii, of an at least trifunctional crosslinker or difunctional chain extender;

89 to 46 wt .-% of an aliphatic-aromatic polyester obtainable by polycondensation of: i) 40 to 60 mol%, based on the components i to ii, of one or more dicarboxylic acid derivatives or dicarboxylic acids selected from the group consisting of: succinic acid, adipic acid, Sebazinic acid, azelaic acid and brassylic acid; ii) 60 to 40 mol%, based on the components i to ii, of a terephthalic acid derivative; iii) 98 to 102 mol%, based on the components i to ii, of a C 2 -C 8 -alkylenediol or C 2 -C 6 -oxyalkylenediol; 0 to 2 wt .-%, based on the polymer obtainable from the components i to iii, of an at least trifunctional crosslinker or di-functional chain extender.

1 to 14 wt .-%, one or more polymers selected from the group consisting of: polylactic acid, polycaprolactone, polyhydroxyalkanoate, polyalkylencarbonat, chitosan and gluten and one or more polyesters based on aliphatic diols and aliphatic dicarboxylic - and

0 to 2 wt .-% of a compatibilizer. Cling foils comprising: a) 99.9 to 98 wt .-% of a biodegradable polyester containing: i) 65 to 80 mol%, based on the components i to ii, of one or more dicarboxylic acid derivatives or dicarboxylic acids selected from the group consisting of: succinic acid Adipic acid, sebacic acid, azelaic acid and brassylic acid; ii) from 35 to 20 mol%, based on components i to ii, of a terephthalic acid derivative; iii) 98 to 102 mol%, based on the components i to ii, of a C2-C alkylenediol or C2-C6-oxyalkylenediol; iv) 0.1 to 2 wt .-%, based on the polymer obtainable from the components I to III, an at least trifunctional crosslinker or difunctional chain extender and

0.1 to 2 wt .-% of a lubricant or release agent.