EP1252016A1

EP1252016A1 - Thermoplastic multi-layered film with a layer of vinylcyclohexane-based polymer

Info

Publication number: EP1252016A1
Application number: EP00988782A
Authority: EP
Inventors: Dirk MÖCKEL; Miroslav Marek; Volker Wege; Friedrich-Karl Bruder; Konstadinos Douzinas
Original assignee: Bayer AG
Current assignee: Covestro Deutschland AG
Priority date: 1999-12-22
Filing date: 2000-12-11
Publication date: 2002-10-30
Also published as: JP2003517951A; DE19962019A1; TWI229637B; AU2510201A; WO2001045937A1

Abstract

The invention relates to a multi-layered film, comprising one layer, which contains a vinylcyclohexane-based polymer, or mixtures thereof and at least one further layer. The multi-layered film is characterised by a high water vapour resistance and a low oxygen permeability.

Description

Thermoformable multilayer film with a layer of vinylcyclohexane based polymer

The invention relates to a multilayer film comprising a layer which contains a polymer based on vinylcyclohexane or mixtures thereof and at least one further layer. The multilayer film is characterized by a high water vapor barrier effect and a low oxygen permeability.

A material used for packaging everyday items, household items, food, various items, semiconductor devices, medicine tablets, etc. requires many functional properties such as e.g. Transparency, moisture impermeability, oxygen barrier, heat sealability, vacuum and air formability as well as hand formability. Such different requirements are not adequately met in all cases by a single polymer layer, so that multi-layer films that are produced by the

Laminating polymer resin films of various chemical compositions are manufactured, have found widespread use. In addition to the use of such laminates for films, there are other areas of application for such laminates, in particular in the production of bottles, oxygen-absorbing packaging material (EP-A 787 764), containers (e.g. medical infusion containers)

JP-A 10 081 795, cold storage bags for cell cultures, antimicrobial laminated tube containers JP-A 10 146 924) and the like.

Multi-layer film packaging is already known. EP-A 450 247 describes multilayer films as packaging material, which e.g. Layers of foil

Have polyester, polyethylene and polyvinyl chloride.

EP-A 477 797 describes biaxially oriented polyolefin multilayer films which are sealable on both sides with a base layer made of propylene polymers and outer layers made of sealable olefin polymers (ethylene-propylene copolymer) with good optical properties

Properties (transparency and gloss). However, propylene polymers can due to the semi-crystalline nature of the polymer, thermoforming only within narrow processing limits.

EP-A 693 369 describes an oriented polyolefin multilayer film consisting of a polyolefinic base layer and at least one sealable cover layer. The

Top layer is made of a sealable polymer made of aliphatic α-olefins and an amorphous polymer. Atactic polystyrene and atactic polyvinylcyclohexane are listed in a variety of amorphous polymers. The multilayer film according to EP-A 693 369 is characterized by good gloss, low haze, low coefficient of friction and low surface roughness.

Films made from polystyrene or polystyrene copolymers are known in the art. Such films are easily thermoformable. The monomers used are inexpensive bulk chemicals. Films made from styrene-containing polymers, however, do not have a special barrier effect against water vapor and are therefore not suitable for packaging moisture-sensitive goods (H. Klein, Permeability of polystyrene film, Kunststoffe (1976), 66 (3), 151-156). The complete hydrogenation of polystyrene produces a polyvinylcyclohexane, which has a significantly improved water vapor barrier compared to polystyrene. This film, which is also easy to thermoform, does not show any special oxygen barrier.

The object of the present invention was to provide a multilayer film with a water vapor barrier layer containing a vinylcyclohexane-based polymer or mixtures thereof and at least one further layer which is characterized by a low oxygen permeability and good printability while maintaining the properties relevant to films and good Processability of the polymers used (no speck formation), thermoformability, sufficient mechanical properties and possibly transparency. Depending on the use of the polymer for the second or further layers, the multilayer films have good sterilizability. It has now been found that a multilayer film which contains a layer of a vinylcyclohexane-based polymer or mixtures thereof and at least one further layer has the desired requirements.

The invention relates to multilayer films comprising at least two layers, characterized in that at least one layer contains a vinylcyclohexane-based polymer (A), with the exception of atactic polyvinylcyclohexane, and at least one further layer containing a thermoplastic polymer (B) or a mixture thereof ,

The multilayer film preferably consists of 2 to 10, particularly preferably 2 to 6, in particular 2, 3 or 4 layers.

The thickness of the overall film can vary widely depending on the application. It is generally 0.01 to 1.5 mm, preferably 0.05 to 1.3 mm and in particular 0.05 to

1 mm.

In the case of use as a flexible container, the thickness can also be up to 7 mm, preferably up to 5 mm.

The multilayer film according to the invention can furthermore have one or more layers e.g. be provided with a paper or metal layer.

Polymer A

Polymers based on vinylcyclohexane are understood to mean homopolymers of vinylcyclohexane and copolymers or block copolymers of vinylcyclohexane and other copolymers.

Preferred as a homo- or copolymer is a vinylcyclohexane-based polymer with the recurring structural unit of the formula (I)

in which

Rl and R ^ are independently hydrogen or C ₁ -C 6 alkyl, preferably CC ^ alkyl and

R3 and R4 independently of one another for hydrogen or for C _r C ₆ alkyl, preferably C _j -C. Alkyl, especially methyl and / or ethyl, or R ^ and R ^ together represent alkylene, preferably C3 or C alkylene (fused 5- or 6-membered cycloaliphatic ring),

R5 represents hydrogen or Ci-Cg-alkyl, preferably C _j -C ^ alkyl,

Rl, R ^ and R ^ independently of one another in particular represent hydrogen or methyl.

Comonomers which can be used in the polymerization of the starting polymer (optionally substituted polystyrene) are preferably used and incorporated into the polymer: olefins with generally 2 to 10 carbon atoms, such as, for example and preferably, ethylene, propylene, isoprene, isobutylene, butadiene, most preferably isoprene and / or butadiene, C _j -Cg- preferably C ₁ -C ₄ - alkyl esters of acrylic or methacrylic acid, unsaturated cycloaliphatic hydrocarbons, such, for example, cyclopentadiene, cyclohexene, cyclohexadiene, optionally substituted norbornene, dicyclopentadiene, dihydrocyclopentadiene, optionally substituted tetracyclododecenes, ring-alkylated styrenes, α-methylstyrene, divinyl benzene, vinyl esters, vinyl acids, vinyl ethers, vinyl acetate, vinyl cyanides such as acrylonitrile, methacrylonitrile, maleic anhydride and mixtures of these monomers. The polymers can generally contain up to 60% by weight, preferably up to 50% by weight, particularly preferably up to 40% by weight, of comonomers (based on the polymer). The polymers 1 to

Contain 30 wt .-% comonomers.

The vinylcyclohexane (co) polymers generally have absolute molecular weights M w weight average of 1,000-10,000,000, preferably 60,000-1,000,000, very particularly preferably 70,000-600,000, determined after

Light scattering.

The vinylcyclohexane-based polymers can be both iso- and syndiotactic. A group of particularly suitable polymers are the vinylcyclohexane-based polymers described in syndiotactic form, preferably with a syndiotactic diad fraction of 50.1 to 74%, in particular 52 to 70% (cf. WO 99/32528).

The polymers can have a linear chain structure as well as branching points due to Co units (e.g. graft copolymers). The branch centers include e.g. star-shaped or branched polymers. The polymers according to the invention can have other geometrical shapes of the primary, secondary, tertiary, optionally quaternary polymer structure, in this case their so-called helix, double helix, leaflet etc. or mixtures of these structures.

Both random and block polymers can be used as copolymers.

Block copolymers include di-blocks, tri-blocks, multi-blocks and star-shaped block copolymers. The vinylcyclohexane-based (co) polymers are prepared by polymerizing derivatives of styrene with the corresponding monomers by radical, anionic, cationic or metal complex initiators or catalysts and then hydrogenating the unsaturated aromatic bonds completely or partially (see, for example, WO 94/21694, EP-A 322 731).

A block copolymer with at least three blocks is preferably used, which contains at least one hard block and at least one soft block, the hard block having at least 50, preferably 60, particularly preferably 65% by weight repeating units of the general formula (II)

embedded image in which

R and R ^ are independently hydrogen or C _j -Cg-alkyl, preferably C 1 -C 4 -alkyl,

R3 for hydrogen or for C 1 -C 6 -alkyl, preferably C 1 -C 4 -alkyl, in particular methyl and / or ethyl, or for fused alkylene, preferably C3 or C4 alkylene (fused-on 5- or 6-membered cycloaliphatic ring),

represent an integer from 0.1 to 5, preferably 0.1 to 3,

contains and the soft block

100-50% by weight, preferably 95-70% by weight, repeating units based on straight-chain or branched C2-Ci4-alkylene, preferably C2-Cg-alkylene and

0 - 50 wt .-%, preferably 5 - 30 wt .-% repeating units of the general formula (II) contains.

The repetition units in the soft block can be distributed statistically, alternating or gradient.

The repeating units according to formula (II) in the hard and soft block can be either the same or different. A hard block and a soft block can themselves in turn contain different repeating units according to formula (II).

The hard blocks of the block copolymers which can be used according to the invention as polymer component A) may contain at most 35% by weight of further repeating units which are based on customary, optionally substituted olefinic comonomers, preferably cyclohexadiene, norbornene substituted by C 1 -C 4 -alkyl,

Dicyclopentadiene, dihydrocyclopentadiene, tetracyclododecene, vinyl ester, vinyl ether, vinyl acetate, maleic acid derivatives and (meth) acrylic acid derivatives are based.

The suitable block copolymer can optionally contain further soft blocks of repeat units based on saturated, optionally substituted by C _] -C4-alkyl, aliphatic hydrocarbon chains with 2 to 10, preferably 2 to 5 carbon atoms and their isomer form.

The proportion of hard blocks (based on the total polymer) is generally 65 to 97% by weight, preferably 75 to 95% by weight, and the proportion of soft ones

Blocks 3 to 35% by weight, preferably 5 to 25% by weight. The block copolymer that can be used generally has molecular weights (number average) of 5,000-1,000,000, preferably 50,000-500,000, particularly preferably 80,000-200,000, determined according to gel permeation chromatography, calibrated with the polystyrene standard. The molecular weight (number average) of the hard blocks is generally 650-970,000, preferably 6,500-480,000, particularly preferably 10,000-190,000. The molecular weight of the soft blocks is generally 150-350,000, preferably 1,500-170,000, particularly preferably 2,400-70,000. The block copolymer can contain hard or soft blocks with different molecular weights.

In addition to the stereoregular head-to-tail link, the linkage of the chain components can have a small proportion of head-to-head linkage. The copolymers can be linear or branched via centers. They can also have a star-shaped structure. Linear block copolymers are preferred in the context of this invention.

The block copolymer can have different block structures, and the end blocks can be a hard or soft block independently of one another. For example, they can be structured as follows:

A ¹ - (B '- A') _n ; B ¹ - (A ^, - B ') _n ; (A '- B ^ _n ;

where A for a hard block, B for a soft block, n> 1, preferably for 1, 2, 3, 4 and i for an integer between 1 and n (1 <i <n)

stand. The hard and soft blocks in the block copolymer are generally incompatible with each other. This incompatibility leads to phase separation on a microscopic scale.

The polymer component which can be used as component A) is preferably prepared in such a way that in a living polymerization process vinyl aromatic monomers of the general formula (III) for the hard blocks and conjugated dienes of the general formula (IV) and optionally vinyl aromatic monomers of the general formula ( III) for the soft blocks

(III) (IN)

embedded image in which

R, R ^, R- and p have the meaning given above and

R4 to R ^ are independently hydrogen, C1-C4 alkyl, preferably methyl,

converted to a prepolymer and then hydrogenated the carbon-carbon double bonds of the prepolymer in the presence of a homogeneous or heterogeneous catalyst.

The monomers of the formula (III) can be either the same or different for the hard and soft block of the prepolymer. A hard block and a soft blocks can contain various repeating units based on monomers of the formula (III).

As comonomers can preferably be used in the polymerization and built into the hard blocks: cyclohexadiene, vinylcyclohexane, vinylcyclohexene, norbornene, dicyclopentadiene, dihydrocyclopentadiene, tetracyclododecene, nucleus-alkylated styrenes, α-methylstyrene, α-methylstyrene, each optionally substituted by C 1 -C 4 -alkyl , Vinyl ether, vinyl acetate, maleic acid derivatives and (meth) acrylic acid derivatives, etc. or a mixture thereof.

The prepolymer can be prepared by a living polymerization process, e.g. a living anionic polymerization or a living radical polymerization can be prepared. Such polymerization methods are generally known in polymer chemistry. A living anionic polymerization process, which is carried out by alkali metals or by alkali metal alkyl compound such as

Methyl lithium and butyllithium can be initiated. Suitable solvents for such polymerization are hydrocarbons such as e.g. Cyclohexane, hexane, pentane, benzene, toluene, etc. and ethers such as e.g. Diethyl ether, methyl tert-butyl ether, tetrahydrofuran.

Various block structures are accessible through a living polymerization process. In the case of anionic polymerization in a hydrocarbon medium such as cyclohexane or benzene, there is no chain termination and no chain transfer with the exclusion of active impurities such as water, oxygen, carbon dioxide, etc. By sequential addition of monomer or monomer mixture

Produce block copolymers with certain block segments. For example, a styrene-isoprene or butadiene diblock copolymer can be prepared by adding the styrene monomer after the diene has completely polymerized. In the present invention, the chain structure is denoted by the symbol (I) _m - (S) _n or (B) _m - (S) _n or, in simplified terms, by IS or BS, m, n mean degree of polymerization in the respective blocks. It is also known that block copolymers with a mixed block (“smeared” block boundary) can be produced by using the favorable cross-polymerization parameters and starting the polymerization in a monomer mixture. For example, styrene / butadiene diblock copolymer can be used with a diene-rich one

Prepare the mixing block as a soft block by initiation in a mixture of styrene and butadiene in a hydrocarbon medium. The polymer chain contains a diene-rich soft block, a transition phase with increasing styrene incorporation rate and a styrene block that ends the chain. The chain structure is denoted by the symbol (I ^{I / s} ) _m - (S) _n or (B ^{B / s} ) _m - (S) _n or simplified by I ^IS S or B ^BS S, where I and B in each case stand for the isoprene-rich and butadiene-rich soft block. The corresponding hydrogenated products are referred to as HI ^IS S or HB ^BS S.

By combining the above two procedures, multi-block copolymers can be produced with both mixed and certain soft blocks. Examples are Triblock SI ^IS S, I ^IS SI and Pentablock S (I ^IS S) ₂ , (I ^IS S) ₂ I. The symbols are self-explanatory. The corresponding hydrogenated products are referred to as H-SI ^IS S, HI ^{! S} SI or HS (I ^IS S) ₂ , H- (I ^IS S) ₂ I.

Control of the molecular weight in anionic polymerization is possible by varying the monomer / initiator ratio. The theoretical molecular weight can be calculated using the following equation:

Total weight of the monomers (g) M = amount of substance of the initiator (mol)

Other factors such as solvents, co-solvents and cocatalysts can also have a sensitive effect on the chain structure. Hydrocarbons like. For example, cyclohexane, toluene or benzene are preferred as solvents for the polymerization in the present invention, since block copolymers with a mixing block can be formed in such solvents and the diene monomer is preferred polymerized highly elastic 1,4-polydiene. An oxygen- or nitrogen-containing cosolvent such as tetrahydrofuran, dimethoxyethane or N, N, N ', N'-tetramethyethylenediamine effects a statistical polymerization and at the same time a preferred 1,2-polymerization of conjugated dienes. In contrast, alkali metal alcoholate such as lithium tert-butoxide also effects statistical polymerization, but has little influence on the 1,2- / 1,4-ratio of diene polymerization. The microstructure of the soft blocks in prepolymer is decisive for the microstructure of the soft blocks in the corresponding hydrogenated block copolymer. For example, a poly-1,4-butadiene block leads to a polyethylene segment during hydrogenation, which can crystallize. The hydrogenation product of poly-1,2-butadiene has too high a glass transition temperature and is therefore not elastic. Hydrogenation of poly-butadiene block with suitable 1.2 / 1.4 ratios can provide an elastic poly (ethylene-co-butylene) segment. In the case of isoprene as comonomer for the soft block, 1,4-polymerization is preferred, since an alternating poly (ethylene-propylene) elastomer block results after hydrogenation.

Temperature, pressure and monomer concentration are largely uncritical for the polymerization. The preferred temperature, pressure and monomer concentration for the polymerization are in the range -60 ° C. to 130 ° C., particularly preferably 20 ° C. to 100 ° C., 0.8 to 6 bar and 5 to 30% by weight (based on the sum from the amount of monomer and solvent).

The process for producing the block copolymers is carried out either with or without, but preferably without, a work-up between the polymerization and hydrogenation stages in order to isolate the prepolymer. Any workup can be done by known

Processes such as precipitation in a non-solvent such as C1-C4 alcohol and C3-C6 ketone, evaporation extrusion or stripping, etc. are carried out. In this case, the prepolymer is redissolved in a solvent for hydrogenation. Without working up, the prepolymer solution can be hydrogenated directly - if appropriate after chain termination and if necessary diluted with the same inert solvent as in the polymerization or with another inert solvent. In this case a saturated hydrocarbon such as cyclohexane, hexane or mixtures thereof is particularly preferred as the solvent for the process.

The vinylcyclohexane-based copolymers or homopolymers are prepared by polymerizing derivatives of styrene with the corresponding monomers by radical, anionic, cationic or metal complex initiators or catalysts and then hydrogenating the unsaturated aromatic bonds completely or partially (see, for example, WO 94/21694, EP-A 322 731).

The hydrogenation of the prepolymers is carried out according to generally known methods (e.g. WO 94/02 720, WO 96/34 895, EP-A-322 731). WO 94/21694 describes a process for the complete hydrogenation of alkenyl aromatic polymers and poly (alkenyl aromatic) / polydiene block copolymers by heterogeneous catalysis.

A large number of known hydrogenation catalysts can be used as catalysts. Preferred metal catalysts are mentioned, for example, in WO 94/21 694 or WO 96/34 896. Any catalyst known for the hydrogenation reaction can be used as the catalyst. Catalysts with a large surface area (for example 100-600 m ² / g) and a small average pore diameter (for example

20 - 500 Ä). Furthermore, catalysts with a small surface area (for example> 10 m ² / g) and large average pore diameters are also suitable, which are characterized by the fact that 98% of the pore volume has pores with pore diameters greater than 600 Å (for example approx. 1,000 - 4,000 Å ) (see e.g. US-A 5,654,253, US-A 5,612,422, JP-A 03076706). In particular, Raney nickel, nickel on silicon dioxide or

Silicon dioxide / aluminum oxide, nickel on carbon as a support and / or noble metal catalysts, e.g. B. Pt, Ru, Rh, Pd used.

The polymer concentrations, based on the total weight of solvent and polymer, are generally 80 to 1, preferably 50 to 10, in particular 40 to 15% by weight. The hydrogenation is general. at temperatures between 0 and 500 ° C, preferably between 20 and 250 ° C, in particular between 60 and 200 ° C, carried out.

The customary solvents which can be used for hydrogenation reactions are described, for example, in DE-AS 1 131 885.

The reaction is generally carried out at pressures from 1 bar to 1000 bar, preferably 20 to 300 bar, in particular 40 to 200 bar.

The process generally leads to a virtually complete hydrogenation of the aromatic units and, if appropriate, of double bonds in the main chain. As a rule, the degree of hydrogenation is higher than 97%, particularly preferably higher than 99%. The degree of hydrogenation can be determined, for example, by NMR or UV

Determine spectroscopy.

The amount of catalyst used depends on the procedure. The process can be carried out continuously, semi-continuously or batchwise.

The ratio of catalyst to prepolymer, for example in the batch process, is generally 0.3-0.001, preferably 0.2-0.005, particularly preferably 0.15-0.01.

The invention further relates to a process for producing the film according to the invention by the extrusion process known per se. The procedure is such that the polymer is metered into a conveyor screw via a metering device, heated and melted and extruded as a melt through a flat die. The melt film is drawn off via a roller system, the film, if appropriate, one after the other or simultaneously in the longitudinal and / or transverse direction or oriented without tempering (in the longitudinal direction by means of high-speed rollers, in the transverse direction, for example with the aid of a tenter frame), thermally fixed, corona or flame treated and finally wound up. It has proven to be advantageous to temper the draw-off roller or rollers in accordance with the glass transition temperature of the polymer.

The layer containing the polyvinylcyclohexane-based polymer can contain a further polar polymer in addition to the vinylcyclohexane-based polymer. For the purposes of the present invention, polar polymers are preferably selected from the group consisting of polycarbonate, polyacetal, polyamide, polyester,

Polyurethane, acrylate or methacrylate polymers or mixtures thereof.

The layer preferably contains 0.05 to 8% by weight of a polar polymer or a mixture thereof based on the total amount of polymer in this layer, particularly preferred are 0.1 to 6% by weight of a polar polymer or one

Mix of this.

The second and optionally further layers generally contain a polymer or a mixture of polymers selected from at least one from the group of polyolefins, polyamides, polycarbonates, polyurethanes and polyesters.

Suitable polyamides are known homopolyamides, copolyamides and mixtures of these polyamides. It can be semi-crystalline and / or amorphous polyamides.

Polyamide-6, polyamide-6,6, mixtures and corresponding copolymers of these components are suitable as partially crystalline polyamides. Also suitable are partially crystalline polyamides, the acid component of which is wholly or partly selected from at least one acid consisting of the group consisting of terephthalic acid, isophthalic acid, suberic acid, sebacic acid, azelaic acid, adipic acid, cyclohexanedicarboxylic acid, the diamine component of which is wholly or partly selected from m - and / or p-xylylenediamine, hexamethylenediamine, 2,2,4-trimethylhexa- methylenediamine, 2,4,4-trimethylhexamethylenediamine and isophoronediamine and the composition of which is known in principle. ,

Also to be mentioned are polyamides which are made wholly or in part from lactams with 7 to 12 carbon atoms in the ring, optionally with the use of one or more of the above-mentioned starting components.

Particularly preferred partially crystalline polyamides are polyamide 6 and polyamide 6,6 and their mixtures. Known products can be used as amorphous polyamides. They are obtained by polycondensation of diamines, preferably selected from ethylene diamine, hexamethylene diamine, decamethylene diamine, 2,2,4- and / or 2,4,4-trimethylhexamethylene diamine, m- and / or p-xylylene diamine, bis- (4- aminocyclohexyl) methane, bis- (4-aminocyclohexyl) propane, 3,3'-dimethyl-4,4'-diamino-dicyclohexylmethane, 3-aminomethyl-3, 5, 5-trimethylcyclohexylamine, 2,5- and / or 2 , 6-bis (aminomethyl) norbornane and / or 1, 4-diaminomethylcyclohexane or mixtures thereof with dicarboxylic acids, preferably selected from oxalic acid, adipic acid, azelaic acid, decanedicarboxylic acid, heptadecanedicarboxylic acid, 2,2,4- and / or 2,4,4-trimethyladipic acid, isophthalic acid and terephthalic acid or mixtures thereof.

Copolymers which are obtained by polycondensation of several monomers are also suitable, furthermore copolymers which are prepared with the addition of aminocarboxylic acids such as aminocaproic acid, aminoundecanoic acid or aminolauric acid or their lactams.

Particularly suitable amorphous polyamides are the polyamides made from isophthalic acid, hexamethylene diamine and other diamines such as 4,4'-diaminodicyclohexylmethane, isophorone diamine, 2,2,4- and / or 2,4,4-trimethylhexamethylene diamine, 2,5- and / or 2,6-bis (aminomethyl) norbornene; or from isophthalic acid, 4,4'-diamino-dicyclohexylmethane and -caprolactam; or from isophthalic acid,

3,3'-dimethyl-4,4'-diamino-dicyclohexylmethane and laurolactam; or from Tereph thalic acid and the isomer mixture of 2,24- and or 2,4,4-trimethylhexamefhylenediamine.

Instead of the pure 4,4'-diaminodicyclohexylmethane, it is also possible to use mixtures of the positionally isomeric diaminodicyclohexalmethanes which are composed of one another

70 to 99 mol% of the 4,4'-diamino isomer

1 to 30 mol% of the 2,4'-diamino isomer 0 to 2 mol% of the 2,2'-diamino isomer

if appropriate, correspondingly more highly condensed diamines obtained by hydrogenating technical-grade diaminodiphenylmethane. Up to 30% of the isophthalic acid can be replaced by terephthalic acid.

Polyamide-6, polyamide-6,6, polyamide-8, -10, -11 and -12 are preferred. Polyamide-6 and polyamide-6,6 are particularly preferred.

The polyamides preferably have a relative viscosity (measured on a 1% strength by weight solution in m-cresol at 25 ° C.) from 2 to 5, particularly preferably from 2.5 to 4.

Preferred polyalkylene terephthalates can be prepared from terephthalic acid (or its reactive derivatives) and aliphatic or cycloaliphatic diols with 2 to 10 carbon atoms by known methods (Kunststoff-Handbuch,

Vol. VIII, pp. 695 ff, Karl-Hanser-Verlag, Munich 1973).

Preferred polyalkylene terephthalates contain at least 80, preferably 90 mol%, based on the dicarboxylic acid component, terephthalic acid residues and at least 80, preferably at least 90 mol%, based on the diol component,

Diols selected from the group consisting of ethylene glycol, propylene glycol, 1,4-butanediol, cyclohexane-1,4-dimethanol or mixtures thereof. In addition to terephthalic acid esters, the preferred polyalkylene terephthalates can contain up to 20 mol%, preferably up to 10 mol%, of other aromatic dicarboxylic acids having 8 to 14 carbon atoms or aliphatic dicarboxylic acids having 4 to 12 carbon atoms, such as residues of phthalic acid, isophthalic acid, naphthalene -2,6-dicarboxylic acid, 4,4'-diphenyldicarboxylic acid, succinic acid, adipic acid, sebacic acid, azelaic acid, cyclohexanediacetic acid.

The preferred polyalkylene terephthalates can in addition to the above. Diols up to 20 mol%, preferably up to 10 mol%, other aliphatic diols with 3 to 12 C-

Contain atoms or cycloaliphatic diols with 6 to 21 carbon atoms, for example and preferably residues of 1,3-propanediol, 2-ethylpropane-1,3, neopentylglycol, 1,5-pentanediol, 1,6-hexanediol, 3-methylpentanediol 2,4, 2-methylpentanediol-2,4, 2,2,4-trimethylpentanediol-1,3 and -l, 6,2-ethylhexanediol-1,3, 2,2,2-diethylpropanediol-1,3, hexanediol-2 , 5, l, 4-di- (ß-hydroxyethoxy) benzene, 2,2-bis (4-hydroxycyclohexyl) propane, 2,4-dihydroxy-l, l, 3,3-tetramethyl-cyclobutane, 2nd , 2-bis (3-ß-hydroxyethoxyphenyl) propane and 2,2-bis (4-hydroxypropoxyphenyl) propane (DE-A 24 07 674, 24 07 776 and 27 15 932).

The polyalkylene terephthalates can be prepared by incorporating relatively small amounts of trihydric or tetravalent alcohols or 3- or 4-basic carboxylic acid, e.g. are described in DE-A 19 00 270 and US-A 3 692 744. Examples of preferred branching agents are trimesic acid, trimellitic acid, trimethylolethane and propane and pentaerythritol.

It is advisable not to use more than 1 mol% of the branching agent, based on the acid component.

Particularly preferred are polyalkylene terephthalates which consist solely of terephthalic acid and ethylene glycol, propylene glycol or 1,4-butanediol or their copolymers with 1,4- Dicyclohexanedimethanol are built up and mixtures of these polyalkylene terephthalates.

The polyalkylene terephthalates generally have an intrinsic viscosity of about 0.4 to 1.5 dl / g, preferably 0.5 to 1.3 dl / g, each measured in phenol / o-dichlorobenzene (1: 1 wt . Parts) at 25 ° C.

Polyesters are described for example in EP-A774490.

Polyolefins in the sense of the invention are polyethylene, polypropylene, poly-1-butene and polymethylpentene, which may contain small amounts of non-conjugated dienes in copolymerized form. Polyolefins are known and are described in Roempp's chemistry dictionary and in the literature cited therein. Polypropylene is preferred.

Polycarbonates in the sense of the invention are those as described, for example, in EP-A

640 655 are described.

Preferred aromatic polycarbonates are polycarbonates based on 2,2-bis (4-hydroxyphenyl) propane or one of the other diphenols mentioned as preferred in EP-A 640 655. Those based on 2,2-bis (4-hydroxyphenyl) propane, 2,2-bis (3,5-dimethyl-4-hydroxyphenyl) propane or 1,1-bis- are very particularly preferred. (4-hydroxyphenyl) -3,3,5-trimethylcyclohexane or mixtures of 2,2-bis (4-hydroxyphenyl) propane and l, l-bis (4-hydroxyphenyl-3,3,5-trimethylcyclohexane ,

Polycarbonates based on bisphenol A are very particularly preferred.

The aromatic polycarbonates generally have average molecular weights M _w of approximately 10,000 to 200,000, preferably 20,000 to 80,000 (determined by gel chromatography after prior calibration). The multilayer films according to the invention can be used widely, for example as blister packs, push-through packs. Veφackungsmaterial.

Blister packs and blister packs are used, for example, for pharmaceuticals, household goods, food products, snacks, cookies, tea bags, etc.

The multilayer film according to the invention can be produced by customary processing techniques known for films, for example by coextrusion, compression molding, dry lamination, wet lamination, vacuum lamination, etc.

Other articles can also be produced from the multilayer film according to the invention, e.g. flexible containers such as flexible bags, laminate tubes, cups, boxes, composite cans, inner bags for storage containers for storing products containing flavorings (e.g. food, non-alcoholic drinks,

Cosmetics).

additives

Additives can be added to the multilayer film according to the invention, which are added to the polymer or polymer mixtures used for film production before or during processing. The aim of such an additive is to facilitate processing or to improve the properties of the end product. Important groups of additives are antiblocking agents, thermal or oxidation stabilizers, antistatic agents, bio-stabilizers, colorants, lubricants,

Light stabilizers, optical brighteners, additives to improve the printability etc.

Suitable antiblocking agents are inorganic additives such as silicon dioxide, calcium carbonate, magnesium silicate, aluminum silicate, calcium phosphate and the like and / or incompatible organic polymers such as polyamides, polyesters, Polyurethanes, polycarbonates, etc. The effective amount of antiblocking agent is in the range from 0.1 to 2% by weight, preferably 0.1 to 0.5% by weight. The average particle size is between 1 and 6 μm, in particular 2 and 5 μm, particles with a spherical shape being particularly suitable.

All common thermal stabilizers can be used as stabilizers. In general, sterically hindered phenols, phosphorus compounds and lactone derivatives can be used either alone or as binary or ternary mixtures. Tear mixtures, in particular of Igranox 1010 (phenol component), Irgafos P-EPQ (phosphorus compound) and HP 136 (lactone derivative) from CIBA Specialty Chemicals, Basel, Switzerland, are particularly preferred.

Preferred antistatic agents are alkali alkane sulfonates, polyether-modified, ie ethoxylated and or propoxylated, polydiorganosiloxanes (polydialkylsiloxanes, polyalkylphenylsiloxanes etc.) and / or the essentially straight-chain and saturated aliphatic, tertiary amines with an aliphatic radical having 10 to 20 carbon atoms, Hydroxy (C 1 -C ₄ ) alkyl groups are substituted, N, N-bis (2-hydroxyethyl) alkylamines having 10 to 20 carbon atoms, preferably 12 to 18 carbon atoms, being particularly suitable in the alkyl radical. The effective amount of antistatic is in the range of 0.05 to 0.3% by weight.

Suitable dyes are dyes and pigments, which can be of an inorganic or organic nature. Examples are titanium dioxide, carbon black, oxides and / or mixed oxides of chromium, nickel, iron, azo pigments and phthalocyanines.

Lubricants are hydrocarbons, such as paraffin oils, waxes (e.g. polyethylene and polypropylene waxes), higher alcohols and carboxylic acids, carboxylic acid esters and amides, glycerides, higher aliphatic acid amides, higher aliphatic acid esters and polydimethylsiloxanes. The effective amount of lubricant is in the range of 0.01 to 4% by weight, particularly preferably 0.25 to 1% by weight. Light stabilizers are additives that protect films from exposure to light. Different classes are distinguished depending on the mechanism of action. Most films contain hydroperoxide decomposers (metal complexes, sulfur-containing organic compounds), quenchers (e.g. nickel complexes of phenols containing sulfide groups), radical scavengers (e.g. sterically hindered amines) and less often UV-

Absorbers (e.g. hydroxybenzophenones, hydroxyphenybenzotriazoles) application. The effective amount of light stabilizers is between 0.01 and 3% by weight, particularly preferably 0.5 and 2% by weight.

Optical brighteners are additives that compensate for the yellowish appearance of some plastic films (blue effect) caused by the absorption of blue wavelength ranges. Examples are triazine-phenycoumarins, benzotriazole-phenyl-coumarins and benzooxazoles. The effective amount is between 0.001 and 0.1% by weight, particularly preferably 0.01 and 0.05% by weight.

Low molecular weight resins can be added to further improve the desired physical properties (e.g. film stiffness, smoother behavior, optics, water vapor permeability). Compatible hydrocarbon resins are low molecular weight polymers whose molecular weight M _w (weight average) is generally in a range from 300 to 8,000, preferably 400 to 5,000, particularly preferably 500 to 2,000. The proportion of the resin is in a range of 1 to 30% by weight, preferably 2 to 30% by weight. Hydrocarbon resins are preferred.

The coverability of the cover film can be improved by appropriately increasing the polarity of the surface. This can be done by corona treatment or by adding organic or inorganic additives. Suitable organic additives are polymers such as polypropylene or polyethylene as homopolymers or copolymers, polyesters, polyamides, polycarbonate, polyacetals, polyurethanes, acrylate or methacrylate polymers or mixtures thereof. Prefers the layer contains 0.05 to 8% by weight. Titanium dioxide, barium sulfate, calcium sulfate or calcium carbonate are suitable as inorganic pigments.

Sealing layers can be applied to the films according to the invention in order to improve the adhesion to films or containers made of thermoplastic polymers. Depending on the application, the sealing layers must be adapted. As materials for sealing layers e.g. Ethylene and propylene polymers with different proportions of polar groups as they result from the copolymerization e.g. with vinyl acetate, acrylate monomers are available or polymers based on copolymers of ethylene or propylene with alpha-olefins and polar monomers are used. Furthermore, grafted (e.g. maleic anhydride) ethylene and propylene copolymers can be used as sealing layers. The sealing temperatures can be set by selecting the correct composition.

For some canned food preservation applications, it is necessary to use oxygen absorbers (e.g. NaHCO ₃ , Na ₂ CO 3 ^{0 <} ^ ^er other carbonates and hydrogen carbonates in conjunction with agents that form or emit carbon dioxide.

Multilayer films can also include oxygen generators (such as peroxides, especially barium peroxide and calcium peroxides) e.g. for packaging live fish and shellfish (e.g. JP 07-289 114, EP-A 905 086).

Multi-layer films can be produced by coextrusion of the polymers used or by separate production of the individual polymer films with a subsequent lamination step using generally known methods.

The multilayer films can be used in a variety of ways, e.g. as blister packaging, food packaging and packaging of electronic items.

The following examples are intended to illustrate the invention: Examples

example 1

Synthesis of the polyvinylcyclohexane based polymer:

The autoclave is flushed with inert gas (nitrogen). The polymer solution used (see Table 1) is filtered through a filter SBF-101-S16 (Loeffler, Filter-Technik, Nettersheim, Germany) and together with the catalyst in the

Autoclave given (Table 1). After sealing, inert gas and then hydrogen are applied several times. After relaxation, the respective hydrogen pressure is set and heated to the corresponding reaction temperature with stirring. The reaction pressure is kept constant after the onset of hydrogen uptake. The reaction time is defined from the heating of the batch up to the time when the hydrogen uptake approaches its saturation value.

After the hydrogenation has ended, the polymer solution is filtered through a pressure filter which is covered with a Teflon fabric (B43-MU10, from Dr. M. Männendorf, Switzerland). The product solution is then passed through a 0.2 μm Teflon filter

(Pall Filtertechnik, Dreieich, Germany) filtered. The polymer solution is stabilized with Irganox XP 420 FF (CIBA Specialty Chemicals, Basel, Switzerland) and filtered again with the 0.2 μm filter mentioned. The polymer solution is then freed from the solvent at 240 ° C., the melt is filtered through a 20 μm filter and the product is processed into granules. Neither aromatic nor olefinic

Carbon-carbon double bonds can be detected using 'H-NMR spectroscopy. Table 1

Hydrogenation of polystyrene

1) Polystyrene, type 158 k, clear, Mw = 280,000 g / mol, BASF AG, Ludwigshafen, Germany

2) Ni / SiO ₂ / Al ₂ O ₃ , Ni-5136 P, Engelhard, De Meem, The Netherlands

3) Determined by Η-NMR spectroscopy

Example 2

Production of a two-layer film by coextrusion:

1st layer of syndiotactic amorphous polyvinylcyclohexane (Example 1)

2nd layer of polyamide 6

Two-layer A-B films are produced by coextmion with a total thickness of 200 μm. The base layer B has a thickness of 100 μm and the cover layer A has a thickness of 50 μm. The base layer is made of polyamide 6 (Durethan ™ B 40, Bayer AG, Leverkusen, Germany) and the top layer is made of amorphous, synodotactic polyvinylcyclohexane (see Example 1).

The system for the production of the coexpression film consists of two extmdems, a coexpression adapter, a slot die, a casting roll, a cooling roll and a take-off and film winding device. The melt of material A is processed by the following extruder: Manufacturer: Fa. Reifenhäuser GmbH, Troisdorf, Germany

Screw 0: 50 mm screw length: 33 D.

Mass temperature: 280 ° C

The melt of material B is processed by the following extmder:

Manufacturer. Stork Plastics Machinery BN., Hengelo, The Netherlands

Screw 0: 45 mm screw length: 25 D.

Mass temperature: 280 ° C

Both extmder are controlled independently. To set the average layer thicknesses, the materials are fed to the extremes using a gravimetric dosing system. The melts are brought together in the coexpression adapter from the company Reifenhäuser and brought to the rotating and tempered casting roller (manufacturer: Reifenhäuser) via the slot die from the company Reifenhäuser. Then the already solidified melt is cooled by the counter-rotating cooling roller (manufacturer: Reifenhäuser) and fed from the take-off device to the film winder.

Comparative Example 1 non-oriented polystyrene monofilm

Polystyrene 158K (BASF, Ludwigshafen, Germany), with a weight average molecular weight M _w = 260,400, a density p = 1.05 g-cm ^"3 , a glass transition temperature T _g = 100 ° C and a melt index of MFR = 27.4 g / 10 min., Is at a melt temperature (nozzle) of 250 ° C with a Göttfert single screw

Extruder (30 mm screw diameter, screw length 25D) extruded via a flat film nozzle (220 mm lip width, gap width adjustable between 0.01 - 0.6 mm). The temperature of the casting roll is 90 ° C. A 50 μm thick, clearly transparent film is obtained, which has a peeling speed of 7.3 m / min. is wound up. Table 2 contains the gas and water vapor permeabilities determined on the monolayer or multilayer film. A multilayer film structure as shown in Example 2 on a polyvinylcyclohexane / polyamide 6 two-layer film composite also increases the gas barrier and, in addition to the high water vapor barrier effect, gives the polyvinylcyclohexane-based film system a high oxygen barrier property.

Table 2: Results

Measuring conditions: Dmck: 1000 mbar, gas humidity: dry, T = 25 ° C, detection by means of a pressure measuring capacitor,

MKS company

2) Numerical values converted to standard conditions (273.15 K) 3) from plastics 66 (1976), H. Klein and H. Vogel, permeability behavior of foils made of polystyrene,

Values from Table 2 for P70 type at 20 ° C

4) comparison

The following measurement methods were used to characterize the raw materials and films:

Melt flow index MFR

The melt flow index was determined in accordance with DIN ISO 1 133 using a LT Meltflixer from SWO Polymertechnik GmbH at 280 ° C. and a weight of 2.16 kg measured.

Molecular weight M _w

The weight average molecular weight M _w , which The weight average molecular weight is given in the description of the examples. A two-detector gel permeation chromatography is used for its determination (0.5% by weight solution, solvent tetrahydrofuran, 25 ° C., polystyrene standard).

The detection is carried out by means of UV absorption spectroscopy at 254 nm and by means of Differential refractometry of the fractions. The calibration is carried out using several polystyrene standards of known molecular weights.

Glass transition temperature T _g

Injection molded body (flat bars 80x10x4 mm) of the samples were made using DMA

Determination according to the gravimetric method, with water vapor permeabilities <1 gd ^" '-m ^{" 2} , the determination was carried out according to DIN 53 122, part 2 according to the electrolysis method.

Gas permeabilities O ₂ , N ₂ , CO ₂

The gas permeabilities for O ₂ , N ₂ and CO ₂ are determined in accordance with DIN 53 380, Part 1 by gas-tight clamping of the respective film pattern in a permeation chamber. In one chamber part the gas to be measured (measuring gas) is given at a defined pressure, in the other evacuated part the chamber is registered with the help of a capacitive pressure sensor the gas part permeating through the film sample. Test conditions are 1000 mbar sample gas, 23 ° C and 0% relative air humidity.

Claims

claims

1. Multi-layer films comprising at least two layers, characterized in that at least one layer contains a vinylcyclohexane-based polymer (A), with the exception of atactic polyvinylcyclohexane, and at least one further layer containing a thermoplastic polymer (B) or a mixture thereof.

2. Multi-layer film according to Claim 1 containing 2 to 10 layers.

3. Multi-layer film according to Claim 1 and 2 containing 2 to 6 layers.

4. Multi-layer film according to Claim 1 to 3, the thickness of the overall film being up to 7 mm.

5. Multi-layer film according to claim 1 to 4, the thickness of the overall film being 0.001 to 1.5 mm.

6. Multi-layer film according to one or more of the preceding claims, wherein the vinylcyclohexane-based polymer A) is a homopolymer,

Copolymer or block copolymer.

7. Multi-layer film according to one or more of the preceding claims, containing as polymer A) a vinylcyclohexane-based polymer with the recurring structural unit of the formula (I)

in which

Rl and R ^ are independently hydrogen or Ci -Cg-alkyl and

R ^ and R ^ independently of one another represent hydrogen or Ci-Cg-alkyl, or R ^ and R ^ together represent alkylene,

R ^{5 represents} hydrogen or C 1 -C ₆ alkyl and

where comonomers selected from the group consisting of olefins, C Cg alkyl esters of acrylic or methacrylic acid, unsaturated cycloaliphatic hydrocarbons, substituted tetracyclododecenes, nuclear alkylated styrenes, α-methylstyrene, divinylbenzene, vinyl esters, vinyl acids, vinyl ethers, vinyl acetate, vinyl cyanides Maleic anhydride and mixtures of these monomers can be added to the polymerization and copolymerized.

Multilayer film according to Claim 1, containing as polymer A) a block copolymer with at least three blocks, which contains at least one hard block and at least one soft block, the hard block having at least 50% by weight repeating units of the general formula (II),

embedded image in which Rl and R ^ independently of one another denote hydrogen or Ci-Cg-alkyl,

R ^ represents hydrogen or Ci-Cg-alkyl or fused alkylene,

p represents an integer from 0.1 to 5,

contains

and the soft block

Contains 100 - 50 wt .-% repeating units based on straight-chain or branched C2-C 14 alkylene and

0 - 50% by weight repeating units of the general formula (II)

contains.

9. multilayer film according to one or more of the preceding claims, containing as polymer B at least one polymer selected from the group of polyamides, polycarbonates, polyolefins, polyurethanes and polyesters.

10. A multilayer film according to one or more of the preceding claims, wherein the layer (A) containing polymer can contain up to 8% by weight of a further polar polymer or a mixture thereof.

11. Multi-layer film according to one or more of the preceding claims, the polar polymers being selected from the group of poly amides, polycarbonates, polyolefins, polyurethanes, polyesters and mixtures thereof.

12. Multi-layer film according to one or more of the preceding claims, the layers additionally containing customary additives.

13. Multi-layer film according to spoke 12, containing at least one additive selected from the group of antiblocking agents, thermal or oxidation stabilizers, antistatic agents, bio-stabilizers, colorants, lubricants, light protection agents, optical brighteners, additives for improving the printability.

14. Use of the multilayer film according to claims 1 to 13 as packaging material.

15. Packaging material made of a multilayer film according to claims 1 to 13.