Moulding compositions from vinyl chloride polymers, graft polymers and polymer lubrifiers with ageing stability.

0001The invention relates to thermoplastic molding compositions for the production of films with improved aging behavior on the basis of compositions which contain vinyl chloride polymers, certain graft polymers, certain resinous copolymer additives and special rubbery copolymers.

0002Vinyl chloride polymers, in particular polyvinyl chloride (PVC), are widespread raw materials for the production of a wide variety of plastic articles. It is known that the combination of vinyl chloride polymers with other substances allows the characteristic profile of properties of the vinyl chloride polymers to be varied or modified over a wide range. For example, PVC that is not modified or only slightly modified (so-called "hard PVC") is suitable for the production of moldings. These molding compositions show medium processing behavior, medium heat resistance with moderate toughness and relatively low flexibility. By combining, for example, polyvinyl chloride with so-called plasticizers with low or medium molecular weights, plastic articles can be produced ("soft PVC types") which have high flexibility and elasticity at use temperatures. Examples of plasticizers for this are Phthalates, epoxy compounds, aliphatic diesters, phosphates, polyesters with molecular weights up to about 3000, trimellitates, citrates or certain aliphatic, optionally chlorinated, hydrocarbons are suitable. These plasticizers are known (eg "Encyclopedia of PVC", Mariel Dekker, INC, New York, 1976).

0003Combinations of so-called polymeric plasticizers (polymers with higher molecular weights) with vinyl chloride polymers also allow the production of soft PVC moldings with improved mechanical properties, for example improved abrasion resistance, elasticity, solvent resistance and, if appropriate, better flame resistance. Such polymeric plasticizers are, for example partially cross-linked butadiene-acrylonitrile copolymers with up to 30% acrylonitrile and Mooney viscosities (ML 4, 100 ° C, (DIN 53 523) from 60-100, (e.g. EP 0 005 736)), certain polyurethanes (DE-PS 1 193 241) and special ethylene-vinyl acetate copolymers which are soluble in organic solvents (for example EP 0 005 736).

0004By combining, for example, vinyl chloride polymers with graft polymers (eg styrene, α-methylstyrene, acrylonitrile and / or methyl methacrylate, grafted onto rubber-like substrates such as butadiene polymers (acrylate rubber) or graft polymers (vinyl chloride grafted onto special ethylene-vinyl acetate copolymers and with 45% vinyl acetate, for example, 55% vinyl acetate ) or by combination with other polyethylene derivatives, plastic blends with high impact strength can be produced.

0005The rubber components of the graft polymer modifications are preferably of a different nature (compared to some of the above polymer plasticizers) than the rubbers that can be used as polymer plasticizers. These differences can be given, for example, by chemical composition, the crosslinking characteristics, the particle morphology and the grafting characteristic.

0006Special modifiers can also be used to improve the heat resistance of vinyl chloride polymers. Suitable modifiers for this are, for example, copolymers of styrene, α-methylstyrene, acrylonitrile and methyl methacrylate.

0007In order to enable the technical processing of this large number of polymer combinations, effective stabilization of the systems, for example against thermal, photolytic and chemical degradation, is necessary. Suitable stabilizers and processing aids are, for example, Ba / Cd, Pb, Sn, Zn stabilizers or organic stabilizers as well as phenolic, optionally S or P-containing antioxidants, epoxy compounds, waxes, low molecular weight and high molecular weight lubricants. Additives that optimize the processing conditions of the respective system are also required.

0008Such auxiliaries and their processing conditions are described, for example, in "Kunststoff Handbuch", Carl Hanser Verlag, Munich (1963).

0009For special applications (e.g. as a film for laminating and laminating) compositions containing vinyl chloride polymers with a very specific requirement profile are required: combination of good toughness, breaking strength, flexibility, elasticity (even at lower temperatures), heat resistance, abrasion resistance, adhesive strength; Possibilities of processing into sheet-like structures by extrusion, calendering, injection molding, deep drawing; Laminability with other materials. The compositions should also have good migration resistance, dimensional stability and special shrink properties. Furthermore, they should have an aesthetic surface quality and can be processed into structures with a decorative appearance using special surface treatment processes. In addition, a comfortable grip property of such materials is required.

0010This complex requirement profile can be obtained in certain proportions by thermoplastic processing, for example the following composition:<ul id="ul0001" list-style="none"><li>Vinyl chloride polymer (e.g. PVC),</li><li>Low molecular weight plasticizers (e.g. dioctyl adipate, phthalates),</li><li>Graft polymer (eg ABS graft polymers), polymer plasticizers (eg butadiene-acrylonitrile rubbers) and</li><li>a complex number of stabilizers for the various components and the overall mixture.</li></ul>

0011Such polymer compositions have disadvantages in application technology which restrict the usability of moldings produced therefrom (in particular as films). Such disadvantages are, for example, unsatisfactory resistance to the effects of aging from light, heat, chemicals, other foreign media and possible chemical interactions between the various components. This aging is noticeable in the loss of mechanical and visual properties (embrittlement, deterioration in color, exudation, etc.).

0012It has now been found that films with high aging resistance can be produced from special thermoplastic molding compositions which meet the application profile.

0013The invention accordingly relates to thermoplastic molding compositions which contain:<ul id="ul0002" list-style="none"><li>A) 25-50 parts by weight of a vinyl chloride homopolymer or copolymer with at least 50% by weight of vinyl chloride</li><li>B) 25-50 parts by weight of a mixture of<ul id="ul0003" list-style="none"><li>B1: 20-100 parts by weight of a graft product obtained by</li><li>B1.1: Polymerization of a monomer mixture of 0-75 parts by weight of (meth) acrylonitrile with 100-25 parts by weight of styrene and / or p-methylstyrene and / or α-methylstyrene and / or methyl methacrylate in the presence of</li><li>B1.2: a rubber polymer, where the weight ratio of the monomer mixture to the rubber polymer can be 1:10 to 10: 1 and represents the rubber polymer,</li><li>B1.2.1: a copolymer of<ul id="ul0004" list-style="none"><li>a) 60-100 parts by weight of an acrylic ester of a C₁-C₁₀-Alcohol,</li><li>b) 0-40 parts by weight of at least one monomer from the series acrylonitrile, methyl methacrylate, vinyl acetate and vinyl ether and</li><li>c) up to 10 parts by weight of a crosslinking bi- or polyfunctional monomer or polymer,</li></ul></li><li>B1.2.2: an ethylene-propylene terpolymer rubber and</li><li>_B2nd : 0-80 parts by weight of a copolymer obtained by polymerizing 0-75 parts by weight of (meth) acrylonitrile and 100-25 parts by weight of at least one monomer from the series styrene, α-methylstyrene, p-methylstyrene and Methyl methacrylate,</li></ul></li><li>C) 0-10 parts by weight of a resinous, thermoplastic copolymer of a styrene-acrylonitrile or methyl methacrylate-acrylonitrile copolymer, which is a staudin^Ger index [η], of ≥ 3, preferably ≥ 4 <maths id="math0001" num=""><img file="EP0101899A2_D0001.tif" /></maths> has and whose [η] radical is in any case above that of the copolymer contained in the base polymer B),</li><li>D) 5-40 parts by weight of a copolymer which is composed of:<ul id="ul0005" list-style="none"><li>D1: an ethylene-vinyl acetate or an ethylene-acrylic ester copolymer with a content of polar component ≥ 50% by weight and with average molecular weights ≥1500 and / or</li><li>D2: an ethylene-vinyl acetate-carbon monoxide terpolymer with a content of polar component ≥ 20% by weight and with average molecular weights ≥ 1500 and / or</li><li>D3: a copolymer</li><li>D3.1: 10-99.9 parts by weight of an acrylic ester of a C₁-C₁₅-Alcohol</li><li>D3.2: 0-90 parts by weight of at least one bi- or polyfunctional monomer with conjugated or unconjugated double bonds in the molecule and optionally</li><li>_D3.3: up to 40% by weight, based on the sum of D1) and D2), of further monomers such as acrylonitrile, vinyl acetate and / or alkyl methacrylates of C₁-C₈Alcohols, with average molecular weights ≥ 1500, the copolymer being said to be uncrosslinked or partially crosslinked and</li></ul></li><li>E) 3-30 parts by weight<ul id="ul0006" list-style="none"><li>E1: a copolymer which is produced from</li><li>E1.1: 60-95 parts by weight of a monomer with two conjugated, olefinic double bonds and / or an acrylic ester of a C.₁-C₆-Alcohol,</li><li>E1.2: 5-40 parts by weight of styrene and / or acrylonitrile and / or methyl methacrylate, if appropriate</li><li>E1.3: up to 10 parts by weight of a crosslinking bis- or polyfunctional monomer or polymer with conjugated double bonds and</li><li>El.4: up to 30 parts by weight of other monomers such as vinyl acetate, (meth) acrylic acid or vinyl ether,</li></ul>wherein component E1 should differ from component D3 in at least one parameter and wherein copolymer E1 should have a gel content of ≥70% and / or<ul id="ul0007" list-style="none"><li>E2: an ethylene-propylene terpolymer rubber with gel contents ≥ 70%.</li></ul></li></ul>

0014For example, chemical composition, crosslinking, gel content, etc. can serve as differentiating parameters for component E1.

0015Preferred molding compositions contain 25-50 parts by weight of component A) 25-50 parts by weight of component B), 1.5-3 parts by weight of component C), 15-35 parts by weight of component D) and 5- 20 parts by weight of component E).

0016Vinyl chloride polymers A) for the purposes of the invention are, for example, polyvinyl chloride, copolymers of vinyl chloride with up to 50% by weight of copolymerizable compounds, preferably with up to 20% by weight of copolymerizable compounds, and graft polymers of vinyl chloride on ethylene-vinyl acetate copolymers (for example with Vinyl acetate content of &lt;50% by weight).

0017Compounds copolymerizable with vinyl chloride include:<ul id="ul0008" list-style="none"><li>Vinyl esters with 1-8 C atoms in the alkyl radical of the carboxylic acid such as vinyl acetate. Vinyl propionate, alkyl acrylates, alkyl methacrylates, alkyl vinyl ethers, propylene, maleic anhydride, half esters and diesters of maleic acid with aliphatic alcohols with 1-8 C atoms in the alcohol residue.</li></ul>

0018The _PFrog polymer (mixtures) B in the sense of the invention are polymer mixtures of 20-100 parts by weight, in particular 50-100 parts by weight of a graft product and 0-80 parts by weight, in particular 0-50 parts by weight of a copolymer. The graft products are prepared by polymerizing a monomer mixture of 0-75 parts by weight of (meth) acrylonitrile, preferably acrylonitrile, with 100-25 parts by weight of styrene, P-methylstyrene and / or methyl methacrylate (preferred monomer mixtures consist of styrene, acrylonitrile, optionally in combination with methyl methacrylate) in the presence of a rubber polymer, the weight ratio of the monomer mixture to the rubber polymer being 1:10 to 10: 1, in particular 2: 8 to 8: 2, can be. Rubber polymers are ethylene-propylene terpolymer rubbers, termonomers being understood to mean, for example, dienes such as dicyclopentadiene, hexadiene- (1,4) - or -5-ethylidene-norbornene-2 ​​or also tricyclopentadiene, heptadiene or octadiene. Such rubber polymers are present in the graft products in uncrosslinked or partially crosslinked form (for example DE-OS 2 539 719).

0019Further rubber polymers are copolymers of 60-100 parts by weight, in particular 80-100 parts by weight, of an acrylic ester of a C.₁-C₁₀-Alcohol. Aliphatic C are preferred₁-C_aAlcohols, particularly preferably butyl acrylate and ethylhexyl acrylate and 0-40 parts by weight, preferably 0-20 parts by weight of a monomer from the series acrylonitrile, methyl methacrylate, vinyl acetate or vinyl ether and up to 10 parts by weight of a crosslinking bi- or polyfunctional monomers, oligomers or polymers (e.g. divinylbenzene, alkylene di (meth) acrylates, triallyl (iso) cyanurate, butadiene, polybutadier, isoprene, allyl methacrylate, allyl vinyl ether, bis-methacrylamides etc.).

0020The copolymers which can be used for mixture B are obtained by copolymerization of 0-75 parts by weight of (meth) acrylonitrile and 100-25 parts by weight of at least one monomer from the series styrene, methylstyrene, p-methylstyrene and methyl methacrylate. Copolymers of styrene, α-methylstyrene and acrylonitrile, optionally in combination with methyl methacrylate, are preferred.

0021In the graft products of mixture B, the rubber is preferably present in a partially or highly crosslinked form (with gel contents of the graft product of 50%, in particular ≥ 70%). The rubber is preferably present in the graft product in particulate form with an average particle size of 0.05-5 μ.

0022ABS polymers which have a crosslinked acrylate or EPDM rubber as the graft base are particularly preferred as component B. The EPDM rubbers preferably have a content of 10 to 90 parts by weight of ethylene, 10-90 parts by weight of propylene and 0.1 to 10 parts by weight of diene monomer.

0023Resin-like, thermoplastic copolymers in the sense of the invention are styrene-acrylonitrile copolymers or methyl methacrylate-acrylonitrile copolymers, which form a jam^Ghe index [η] of a 3, preferably ≥ 4 <maths id="math0002" num=""><img file="EP0101899A2_D0002.tif" /></maths> have (measured at 25 ° C dimethylformamide (DMF)). The Staudinger indices of this thermoplastic component must in any case be higher than the Staudinger indices of the copolymers contained in the base polymer B) (ie the resin components contained in the ABS graft copolymer). Methyl methacrylate / acyl nitrile copolymers are particularly suitable as component C with 5-50% by weight of incorporated acrylonitrile. Particularly preferred polymers C consist of 15-40% by weight of acrylonitrile and 85-60% by weight of methyl methacrylate and have an uncrosslinked structure (for example recognizable by their solubility in suitable organic solvents such as DMF). These copolymers may optionally contain a smaller proportion of methacrylic acid ester of C.₂-C_aAlcohols and acrylic acid esters from C₁-C₆-Alcohols included.

0024Components D3 in the sense of the invention exhibit copolymers<ul id="ul0009" list-style="none"><li>_D3.1: 10-99.9 parts by weight (preferably 70-99.9 parts by weight of at least one acrylic ester of a C₁-C₁₅Alcohol (preferably an aliphatic alcohol), preferably butyl acrylate, hexyl acrylate, methyl acrylate, ethyl acrylate, butyl acrylate or ethyl hexyl acrylate is particularly preferred,</li><li>D3.2: 0-90 parts by weight (preferably 0.1-30 parts by weight) of at least one di- or polyfunctional monomer with conjugated or uncojugated double bonds in the molecule (such as divinylbenzene, alkyl (meth) acrylates, triallyl ( iso) cya nurate, butadiene, isoprene, allyl (meth) acrylate) and</li><li>_D3.3: up to 40% by weight, in particular up to 30% by weight, based on the sum of D1) and D2), of further monomers such as acrylonitrile, vinyl acetate and / or alkyl methacrylates of C₁-C₈Alcohols, preferably methyl methacrylate; these copolymers can be uncrosslinked or partially crosslinked; the soluble copolymer fractions present in the copolymers should have molecular weights of 1000-2000000, preferably molecular weights ≥ 20,000; particularly preferred are copolymers D3, consisting of 5-35 parts by weight of acrylonitrile, optionally in a mixture with methyl methacrylate and / or vinyl acetate, 85-65 parts by weight of butyl acrylate, optionally in a mixture with ethylene hexyl acrylate and 0-10 parts by weight polyfunctional monomers; these products are preferably partially crosslinked, have gel contents ≥30% and swelling indices (measured in dimethylformamide) in the range from 10-60, preferably in the range from 15-40. Also suitable as component D are ethylene-vinyl acetate or acrylic ester copolymers with a polar component content of 50 50%, preferably 60 60% and average molecular weights 15 1500, preferably 100 10000, particularly preferred ₉100000; ethylene-vinyl acetate-carbon monoxide terpolymers with a polar component content of ≥ 20% are also suitable.</li></ul>

0025Component E in the sense of the invention is an ethylene-propylene terpolymer rubber with the above-mentioned diene monomers as termonomers, such a rubber preferably being crosslinked (gel contents 70 70% by weight).

0026Components E1) in the sense of the invention are copolymers of<ul id="ul0010" list-style="none"><li>_E1.1: 60-95 parts by weight (preferably 65-86 parts by weight) of a monomer with conjugated, olefinic double bonds (eg butadiene, isoprene, chloroprene) and / or an acrylic ester of a C.₁-C₆-Alcohol (e.g. ethyl, butyl, hexyl acrylate),</li><li>El.2: 5-40 parts by weight (preferably 15-35 parts by weight) of styrene and / or acrylonitrile and / or methyl methacrylate, if appropriate</li><li>E1.3: up to 10 parts by weight of a crosslinking bis- or polyfunctional monomer or oligomer or polymer with conjugated or non-conjugated double bonds and</li><li>E1.4: up to 30 parts by weight of further monomers, for example vinyl acetate, (meth) acrylic acid, vinyl ether, methoxymethacrylamide, preferably vinyl acetate.</li></ul>

0027Such copolymers should have a gel content of ≥ 70% and in at least one parameter, for example chem. Composition, crosslinking, gel content, swelling index may differ from copolymer D3).

0028Preferred copolymers are copolymers of 20-35 parts by weight of acrylonitrile, 80-65 parts by weight of butadiene with gel contents ≥ 70% or copolymers of 15-35 parts by weight of acrylonitrile, 85-65 parts by weight of alkyl acrylate and 0.1 4-10 parts by weight of a crosslinking agent (the latter can be polyfunctional vinyl or allyl monomers, for example butadiene, isoprene, diene oligomers, polydienes, C₂-C₃₀Alkylenes with terminal polymerizable groups, preferably (meth) acrylic acid esters, polybutadiene cores in crosslinked form, onto which alkyl acrylate has been grafted in a mixture with acrylonitrile); these copolymers may contain vinyl acetate incorporated proportionally.

0029Components E1 should differ from components D3 in at least one parameter. The different effects of components E1 and D3 in the composition according to the invention can preferably be adjusted by the chemical composition and the strength of the crosslinking (or non-crosslinking) (expressed by gel content, swelling index, molecular weight of the soluble fraction).

0030Components D and E of the molding compositions according to the invention can also be used to produce the molding compositions according to the invention if they are present as special graft polymers (= graft polymers from the vinyl chloride polymers forming component A on the polymers D and E as a graft base).

0031The vinyl chloride polymers suitable according to the invention can be prepared by known industrial processes, for example emulsion, suspension or bulk polymerization processes.

0032Processes such as emulsion, suspension, bulk, solution-precipitation polymerization processes can be used to produce the suitable graft products. Particularly suitable processes are emulsion polymerizations, solution polymerizations or combinations of emulsion polymerizations, solution polymerizations or combinations of emulsion or solution and suspension polymerizations.

0033Particularly preferred graft polymers are obtained by free radicals in an aqueous emulsion (in the presence of emulsifiers, radical formers, regulators, etc.) in a first stage to form an aqueous latex, a latex particle size of approx. 0.05-5 u polymerized (optionally in combination with known latex particle agglomeration processes) and in the presence of this rubber latex the vinyl monomers mentioned (preferably styrene, acylonitrile, methyl methacrylate) - radically polymerized in such a way that graft polymers of the vinyl monomers are formed on the rubber latex particles.

0034A preferred method for producing the graft products based on ethylene-propropylene rubber is the known solution or bulk polymerization with so-called "phase inversion" and subsequent termination of the graft polymerization in the melt, solution or suspension.

0035If copolymers B2 are also used for the polymer mixtures according to the invention, their production process is irrelevant for the properties of the molding compositions according to the invention, ie as copolymers B2 it is possible to use resins which are obtained by emulsion, suspension, dispersion, bulk, precipitation or solution polymerizations were obtained. Following such polymerizations, antioxidants (for example of the phenol type) can optionally be added. The polymers can be isolated from graft polymer latices by known methods (for example in the form of powders), for example by coagulation by adding electrolytes, acids or solvents, combined with subsequent dewatering of the powders by drying processes. The suitable thermoplastic additives of component C) are to be produced by emulsion or suspension processes, in the presence of known surface actions, substances and initiators, preferably free radical formers. Such polymers can either be isolated from the latex form obtained (for example by spray drying or electrolyte coagulation) or the latices obtained can be combined with other latices of the compositional component according to the invention (for example with the ASA latex and / or the components D) and F) which may be present as latex)) mixed and coagulated together.

0036Such co-coagulation processes lead to component mixtures (as constituents of the composition according to the invention) which are particularly preferred and lead to molding compositions with special, good properties (for example improved processing behavior of the compositions according to the invention).

0037Components D) which are suitable according to the invention can be prepared by known processes by free-radical copolymerization processes, for example emulsion polymerizations, solution, bulk or suspension polymerizations and combinations of emulsion and suspension polymerizations. The procedure of aqueous emulsion polymerization and solution polymerization is particularly preferred. The polymers are following the_HCreation process isolated by known methods, for example by filtration, coagulation, evaporation, preferably by coagulation of emulsions.

0038As with the other components of the molding compositions according to the invention, the individual components can be equipped or stabilized with conventional antioxidants, thermal stabilizers or light stabilizers during or after the production process.

0039The components E) are preferably produced in such a way that the material can be crosslinked to 70% gel gel content. A preferred production process for component E) is therefore emulsion polymerization (for example in aqueous media). Other manufacturing processes are, for example, solution polymerizations (with the formation of an essentially uncrosslinked material) and the subsequent action of crosslinking agents which brought about the necessary crosslinking (e.g. in bulk or after dispersing the pre-condensate obtained by solution polymerization). Conventional radical formers and also suitable jets can be used in these processes.

0040A particularly suitable method is aqueous emulsion polymerization with subsequent coagulation of the resulting aqueous latices.

0041The molding compositions according to the invention can be processed by customary methods of plastics processing, for example by injection, extrusion, blow molding, deep drawing, calendering. The molding compositions are preferably suitable for the production of films.

0042The intrinsic viscosities (Staudinger indices) were determined in the specified solvent.

0043For the definition of the Staudinger index, swelling index, gel content, see M. Hoffmann, H. Krömer, R. Kuhn "Polymer Analysis I and II", Georg-Thieme Verlag (Stuttgart 1977).

0044The graft rubber particle sizes are d₅₀-Values ​​(diameter) (for definition see ultracentrifuge measurements: W. Scholtan, H. Lange, Kolloidz. And Z. Polymer 250 (1972) 783-796).

0045To produce the molding compositions described in Table 2, X parts by weight of polyvinyl chloride (K value 70) are combined with different amounts of different products (Table 1). In each case, 2% by weight of Ba / Cd laurate (solid), 0.3% by weight of sterically hindered phenolic antioxidant (solid) and 0.2% by weight of ester wax were added as a necessary stabilizer and lubricant additive. The molding compositions were homogenized on a mixing roll mill at 180 ° C. for 10 minutes and pressed to test specimens at 190 ° C.<tables id="tabl0001" num="0001"><img file="EP0101899A2_D0003.tif" /></tables><tables id="tabl0002" num="0002"><img file="EP0101899A2_D0004.tif" /></tables><tables id="tabl0003" num="0003"><img file="EP0101899A2_D0005.tif" /></tables><tables id="tabl0004" num="0004"><img file="EP0101899A2_D0006.tif" /></tables><tables id="tabl0005" num="0005"><img file="EP0101899A2_D0007.tif" /></tables>