NO750022L - - Google Patents

Description

The invention relates to thermoplastic molding compounds

with high dimensional stability to heat and high impact strength and made from vinyl chloride polymers and certain polycarbonates. The casting mixtures may contain elastifiers such as rubber and/or rubber-modified thermoplastic resins to increase their toughness and shear strength.

The freezing temperature (glass transition temperature) of polyvinyl chloride is approx. 80°C, so that its dimensional stability to heat (Vicat temperatures around 75 to 84°C depending on K value and formulation) is insufficient for many purposes. Attempts have therefore been made to improve the dimensional stability against heat by modifying the molecular structure (copolymerisation), carrying out chemical finishing treatments' or adding thermoplastics with a higher glass transition temperature (G. Kunne et al5Kunststoffe volume 63 (1973), page 139-1^2) . Partial results have been obtained by post-chlorination and cross-linking as well as by copolymerization with. maleinimides (Vicat temperatures approx. 90°C). Attempts have also been made to mix PVC with other thermoplastics. However, technically valuable products were only obtained in a few cases.

The molding mixture according to the invention consists of:

(a) 20 - 90% by weight (based on a) and b)) of polyvinyl chloride

and copolymers of vinyl chloride and up to 30% by weight of a

or more copolymerizable vinyl compounds; (b) 10 - 80% by weight (based on a) and b)) of a polycarbonate,

in which at least 50% by weight of the structural units have formula (1):

CH,£K^

— 0 -<y y_x—<^y— 0 - c — (1)

CH 3

wherein X means a single bond, -0-, -CO-, -SO2-, C-^- C-^q alkylene, Cl~C10alkylideneJC5~ C]_5 cycloalkylene, C^- C-^ cycloalkylidene, C5~C20cycloalkylalkylidene, or

and

(c) 0-100% by weight based on the mixtures (a) and (b), rubber and/or a rubber-modified thermoplastic resin. Particularly preferred casting mixtures consist of: (a) 30 - 90% by weight of a vinyl chloride homo- or copolymer, wherein up to 30% by weight of other vinyl compounds have been polymerized; (b) 10 - 70% by weight of a polycarbonate of formula (2):

where n means approx. 30 to 1000

or a polycarbonate, in which at least 50% by weight of the structural units have formula (2) and the remaining standing structural units have formula (2 a)

and

. (c) 10 to 50 wt%, based on the mixture of (a) and (b) of a rubber and/or a rubber-modified thermoplastic resin.

The molding compositions according to the invention can be prepared by dissolving their polymeric components in suitable solvents and evaporating the solution by mutual precipitation. If desired, compo-

The nents are therefore mixed mechanically by usual methods.

Casting compounds which have a high impact strength and high shear strength and in many cases can also be transparent can be obtained by the addition of rubber or certain rubber-modified resins. Without the addition of rubber or rubber-modified resins, the molded compounds formed, which may be transparent, usually have a lower impact strength.

Pol ycarbonates■

Suitable polycarbonates according to the invention are homo- or co-polycarbonates and mixtures of different homo- and co-polycarbonates. The polycarbonates usually have molecular weights of 10,000 to 200,000 (average molecular weight), preferably 20,000 to 80,000. They can, for example, be produced by the interphase polycondensation process from phosgene and bisphenols (see DOS no. 2,063,050, 2,063,052, 1,570,703, 2,211,956, 2,211,957 and 2,248,817

and French Patent No. I.56I.518). The polycarbonate units with formula (1) can, for example, be based on the following bisphenols: Bis-(3,5-dimethyl-4-hydroxypheny1)

bis-(3,5-dimethyl-4-hydroxyphenyl) ether

bis-(3,5-dimethyl-4-hydroxyphenyl)-carbonyl

bis-(3,5-dimethyl-4-hydroxyphenyl)sulfone

bis-(3,5-dimethyl-4-hydroxyphenyl)-methane

1,1-bis-(3,5-dimethyl-4-hydroxyphenyl)-ethane

1,1-bis-(3,5-dimethyl-4-hydroxyphenyl)-propane

2,2-bis-(3,5-dimethyl-4-hydroxyphenyl)-propane

2,2-bis-(3,5-dimethyl-4-hydroxyphenyl)-butane

2,4-bis-(3,5-dimethyl-4-hydroxyphenyl)-2-methylbutane

2,4-bis-(3,5-dimethyl-4-hydroxyphenyl)-butane

3,3-bis-(3,5-dimethyl-4-hydroxyphenyl)-pentane

3,3-bis-(3,5-dimethyl-4-hydroxyphenyl)-hexane

4.4-bis-(3,5-dimethyl-4-hydroxyphenyl)-heptane

2,2-bis-(3,5-dimethyl-4-hydroxyphenyl)-octane

2,2-bis-(3,5-dimethyl-4-hydroxyphenyl)-nonane

■2,2-bis-(3,5-dimethyl-4-hydroxyphenyl)-decane

1,1-bis-(3,5-dimethyl-4-hydroxyphenyl)-cyclohexane

1,4-bis-(3,5-dimethyl-4-hydroxyphenyl)-cyclohexane

α,α'-bis-(3,5-dimethyl 1-4-hydroxyphenyl)-p_-diisopropylbenzene α,α'-bisp(3,5-dimethyl-4-hydroxyphenyl)-m-diisopropylbenzene.

The following are preferred: Bis-(3,5-dimethyl-4-hydroxyphenyl)-methane

2,2-bis-(3,5-dimethyl-4-hydroxyphenyl)-propane

2,4-bis-(3,5-dimethyl-4-hydroxyphenyl)-2-methylbutane

1.1-bis-(3,5-dimethyl-4-hydroxyphenyl)-cyclohexane and

α,α'-bis-(3,5-dimethyl-4-hydroxyphenyl)-p-diisopropylbenzene. 2,2-bis-(3s5-dimethyl-4-hydroxyphenyl)-propane is particularly preferred.

In addition to units of formula (1), the polycarbonates can contain up to 50% by weight of units derived from other bisphenols, e.g. those in which at least one of the ortho phenyl groups is unsubstituted, substituted or substituted by halogen (e.g. chlorine or bromine). The following are examples:

Hydroquinone, resorcinol,

dihydroxydipheny1,

bis-(hydroxyphenyl)alkanes,

bis-(hydroxyphenyl)-cycloalkanes,

bis-(hydroxyphenyl)sulfides,

bis-(hydroxyphenyl) ethers,

bis-(hydroxyphenyl) ketones,

bis-(hydroxyphenyl) sulfoxides,

bis-(hydroxyphenyl)-sulfones and

α,α'-bis-(hydroxyphenyl)-diisopropylbenzenes.

The following are particularly preferred: 2,2-bis-(4-hydroxyphenyl)-propane,

1.1- bis-(4-hydroxyphenyl)-cyclohexane,

2.2- bis-(3,5-dichloro-4-hydroxyphenyl)-propane,

2,2-bis-(3,5-dibromo-4-hydroxyphenyl)-propane,

ot,a'-bis-(4-hydroxyphenyl)-£-di is opropyl lbenzene and

2,2-bis-(3-methyl-4-hydroxyphenyl)-propane.

These and other aromatic dihydroxy compounds and polycarbonates thereof are disclosed in US Patent Nos. 3-028,'365s 2,999-835, 3,148,172, 3,271,368, 2,991,273, 3,271,367, 3,780,078, 3,014,891 and

.2.999-846 and in DOS no. 1.570.703-

The polycarbonates may be branched by incorporating smaller amounts of polyhydroxyl compounds, e.g. 0.05 to 2.0 mol%

(based on the amount of bisphenols used). Polycarbonates of this type are mentioned, for example, in DOS no. 1,570,533, 2,116,974 and 2,113-347, in German patents no. 885-442 and 1,079-821 and US patent no. 3^544,514. The following are examples of some suitable polyhydroxyl compounds: Phloroglucinol, 4,6-dimethyl-2,4,6-tri-(4-hydroxyphenyl)-heptene-(2) , 4,6-dimethyl-2,4,6-tri- (4-hydroxyphenyl)-heptane, 1,3,5-tri-(4-hydroxyphenyl)-benzene, 1,1,. l-t r i-(4-hydroxypheny1)-ethane , tri-(4-hydroxyphenyD-phenylmethane, 2 , 2-bis-_/~4 , 4 - (4 , 4 '-dihydroxydipheny1)-cyclohexyl7-propane, 2 ,4-bis-(4-hydroxyphenyl-4-isopropyl)-phenol, 2 ,6-bis - (2 '-hy dr oxy-5 '-methylbenzy 1)-4-methyl 1-phenol, 2 . -methyl) -benzene .

The mixtures according to the invention may contain vinyl chloride polymers. which are formed by emulsion, suspension or mass polymerization and which have K values according to Fikentscher, of from 50 to 80 determined in cyclohexanone (1% solution at 23°C).- Suitable vinyl chloride polymers of this type are polyvinyl chloride and copolymers of vinyl chloride obtained from at least 70% by weight of vinyl chloride and not more than 30% by weight of a vinyl compound. The following are examples of vinyl compounds suitable for copolymerization with vinyl chloride: Vinylidene chloride and vinylidene fluoride, vinyl esters such as vinyl acetate, vinyl propionate or vinyl benzoate, acrylic acid or methacrylic acid and their alkyl esters, amides and nitriles of acrylic and methacrylic acid, -maleic acid esters and semi-esters, maleimides, vinyl ethers and olefinically unsaturated hydrocarbons such as ethylene, propylene or butylene. Rechlorinated polyvinyl chloride is also suitable.

Rubbers suitable for use according to the invention are

especially natural rubber and synthetic rubbers. The following synthetic rubbers can be used, for example: Polypentenamer, ethylene-propylene-diene rubber (diene e.g. 1,5-hexadiene, norbornadiene, ethylidene norbornene), diene rubbers, e.g. homopolymers of conjugated dienes, containing 4-8 carbon atoms, such as butadiene, isoprene, piperylene and ■chloroprene, copolymers of such dienes with each other and copolymers of such dienes with styrene, acrylic or methacrylic compounds (e.g. acrylonitrile, methacrylonitrile, acrylic acid, methacrylic acid , butyl acrylate or methyl methacrylate) or isobutylene. Particularly preferred rubbers are butadiene, butadiene styrene, butadiene-methyl methacrylate, butadiene-butyl acrylate, ethylene-propylene-diene, polypentenamer and butadiene-acrylonitrile rubbers, some of which may either contain small amounts of other monomers condensed with them, e.g. divinylbenzene and methacrylic acid in the case of the latter rubber. Elastomeric polyurethanes, silicone rubbers, polyether rubbers and chlorinated low-pressure polyethylene are also suitable.

with a chlorine content of 20 to 50% by weight, as well as copolymers of ethylene and vinyl acetate with a vinyl acetate content of 15 to 65% by weight, preferably 30 to 65% by weight. ■

The following are rubber-modified thermoplastic resins that can be used in accordance with the invention: (A) Graft polymers of vinyl compounds (a) on rubber (b); or (B) Blends of graft polymers (A) and thermoplastic resins (c) produced by polymerization of vinyl compounds (a), or (C) Blends of rubbers (b) with thermoplastic resins (c).

The following are examples of suitable vinyl compounds

(a):

1. Styrene and its derivatives, e.g. α-methylstyrene, α-chlorostyrene, p_-chlorostyrene, 2,4-dichlorostyrene, p-methylstyrene, 3,4-dimethylstyrene, o- and p-divinylbenzene, p-methyl-α-methylstyrene and p_chloro -α-methylstyrene. 2. Acrylic and methacrylic compounds, e.g. acrylic and methacrylic acid, acrylonitrile, methacrylonitrile, methyl methacrylate, ethyl acrylate, n- and isopropyl acrylate, n- and isobutyl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, n- and isopropyl methacrylate, n- and iso-butyl methacrylate, cyclohexyl methacrylate and iso-bornyl methacrylate. 3. Vinyl chloride or vinyl monomers which may be copolymerized with vinyl chloride.

The resins and grafting polymers can be prepared by ordinary radical polymerization, e.g. by solvent-free dissolution, dissolution/precipitation, suspension or emulsion polymerisation. The graft polymers or rubbers and resins can be mixed using conventional methods, e.g. on rollers or kneaders or by mixing suitable latexes, then isolation of the products by mutual precipitation.

The following rubber-modified resins are preferred: Graft polymers of styrene, α-methylstyrene, acrylonitrile, methacrylic acid ester or mixtures thereof on a rubber, e.g. polybutadiene

or a butadiene copolymer and mixtures of such graft polymers with polystyrene or styrene copolymers.

Preferably, the preferred rubber-modified ones have the following composition:

I. Graft polymers of:

(I 1) 5 - 90% by weight, preferably 10 - 60% by weight of a rubber-elastic butadiene polymer or copolymer containing up to 50% by weight of copolymerized styrene, acrylonitrile and/or alkyl esters of acrylic or methacrylic acid, containing 1 to 10 C atoms in the alcohol group which

graft base and

(I 2) 10 - 95% by weight, preferably 40 - 90% by weight of a monomeric mixture of

(I 2.1) 50 - 100 parts by weight of styrene, α-methylstyrene, C-^- C-^q

alkyl esters of acrylic and methacrylic acid and mixtures thereof, (I 2.2) 0-50 parts by weight of acrylonitrile, methacrylonitrile, - C-j^q alkyl esters of acrylic or methacrylic acid or mixtures thereof which have been polymerized in the presence of (I 1).

II. Mixtures of:

(II 1). 5-80% by weight of polymer (I) and (II 2) 20-95% by weight of a thermoplastic polymer or copolymer of monomers (12).

III. Mixtures of:

(III 1) 5 - 60% by weight of a rubber according to (I 1) and (III 2) 40 - 95% by weight of a thermoplastic polymer according to (II 2).

Polycarbonates containing structural units of formula

(1) is surprisingly very compatible with polyvinyl chloride, with the result that the casting mixture according to the invention has good physical properties. • Some of the molding compounds are surprisingly also transparent, especially when using polycarbonates based on 2,2-bis-(3,5-dimethyl1-4-hydroxyphenyl)-propane or 2,4-bis-(3,5-dimethyl1-4 -hydroxy-phenyl)-2-methylbutane. Polycarbonates containing structural units of formula (1), for example those based on 2,2-bis-(3,5-dimethyl-4-hydroxyphenyl)-propane and 2,4-bis-(3,5-dimethyl-4-hydroxyphenyl) -2-methylbutane can be dissolved together with PVC in a PVC solvent.

No phase separation takes place. Polycarbonates based on bisphenol A do not have these properties.

Another surprising quality of the casting mixture according to the invention is the ease with which they can be worked up; thus, the mixture of polyvinyl chloride and, for example, polycarbonates based on o,o,o',o'-tetramethyl-substituted bisphenols can be processed thermoplastically at 240 - 260°C, while the pure polycarbonate can only be processed at higher temperatures at approx. 300 - 330°C.

The casting mixture according to the invention has surprisingly high heat resistance temperatures. Vicat temperatures according to DIN 53 460 (5 kp!) of 130 - 135°C are achieved with a polycarbonate content of about 50% by weight. Compared to polyvinyl chloride, the molding compounds are clearly improved in their hardness, tensile strength, flexural strength and E-modulus.

Regardless of the conditions in which the components are mixed, some molding compounds are to a large extent transparent, especially when polycarbonates are used, based on 2,2-bis-(3,5-dimethyl-4-hydroxy-phenyl)-propane and 2,4-bis- (3,5-dimethyl-4-hydroxyphenyl)-2-methylbutane.

However, casting mixtures made from polyvinyl chloride and the above-mentioned polycarbonates do not have a sufficient impact strength for all purposes.

However, toughness and shear strength can be improved considerably by adding rubber-modified thermoplastic resins.

The addition of such resins usually destroys the transparency of the molding mixture so that more or less opaque products are obtained. In the transparent casting mixtures according to the invention, it is surprisingly found that the transparency is retained after the addition of rubber-modified resins which have practically the same refractive index as the casting mixture.

The casting mixture according to the invention is considerably more flame resistant than pure polycarbonates and substantially resistant to acids, alkalis and solvents.

In the polymer mixture according to the invention, the rubber usually forms a separate phase which is finely divided in the polymer mixture.

The rubber can be present in the form of individual pellets in agglomerates of pellets or in the form of other regular or irregular particles and agglomerates or also in the form of network-like particles, in which other polymers are embedded. The particle size is usually 0.01 to 20 µm, preferably 0.03 to 10 µm. They can consist of one or more different types, depending on the method used for producing the polymer mixture and the choice of individual components and individual particle types can vary significantly from one another in shape, size and particle size distribution. Two polymer mixtures which have the same rubber content and are otherwise identical in composition can differ significantly in their properties due to different rubber phases, e.g. can they be separated in toughness and surface gloss.

While the rubber content usually forms a separate phase

in the polymer mixture according to the invention, the other polymer compo-

nents of the mixture form a common phase, in which the different polymers can be approximately molecularly dispersed or they can form several phases.

Each of these phases can consist of an approximately molecularly dispersed mixture of different polymers.

The casting mixture according to the invention can be obtained by mixing the polycarbonate with polyvinyl chloride by adding a common stabilization system, followed by homogenization in mixing equipment, such as rollers, mixing screws, mixing extruders, internal mixers or kneaders. Because operating temperatures up to 260°C are used, it is advisable to add the total amount of required stabilizer to the polyvinyl chloride and mix vigorously in a high-speed mixer (temperature up to 150°C) before mixing the polyvinyl chloride with the polycarbonate. For example, the polyvinyl chloride can be added as a stabilized granule to the usually powdered or granulated polycarbonate and this mixture can then be homogenised. Alternatively, the two polymers can be melted separately, for example in extruders and the two melts can then be combined or the polycarbonate or polyvinyl chloride can first be melted separately, e.g. on rollers and the second component can then be added.

The casting mixture according to the invention can also be prepared by solutions by dissolving their components in a solvent or solvent mixture and then isolating them by adding a non-solvent or by pouring the solution dropwise into a precipitating agent or by evaporating the solvent .

The molding compounds can be worked up as powders or granules to form shaped products of any type by conventional thermoplastic molding methods.

Rubber-modified resins are usually obtained in a powdered friable form and can be used as such without special pre-mixing or thermoplastic homogenization process. If desired, however, the polyvinyl chloride or polycarbonate may first be mixed with the resin. The casting compounds according to the invention can be stabilized by means of usual polyvinyl chloride stabilizers, based on lead, barium/cadmium, calcium/zinc, organo-tin compounds or organic PVC stabilizers which are used either alone or in combination. The choice of lubricant also depends on the necessity of the PVC. The stabilization of PVC is particularly important, because depending on the amount of polycarbonate used, the processing temperature of the casting mixtures is just up to the upper tolerance limit for PVC. In many cases, it would be necessary to use a higher total concentration of stabilizer than for pure PVC.

The addition of color pigments, fillers, glass fibres, antistatic substances, flame retardants and plasticizers is possible in principle to achieve special properties or effects.

Physical or chemical propellants can also be added to the casting mixtures according to the invention to form a foam structure under suitable operating conditions.

The operating temperatures necessary for the premixing process, e.g. incorporation of PVC stabilizer and if indicated homogenization of the total mixture prior to exposure to heat in the high course mixer is within the range of 20 to 50°C. The subsequent processing of the product into a granule or finished parts should preferably be carried out at temperatures not higher than 260°C, the required temperature depending both on the viscosity and the polycarbonate used and the quantity thereof. With a relatively low polycarbonate content of up to approx. 30%, the product can be processed in much the same way as PVC with a high K value, but if the amount of polycarbonate is high, the temperature used must likewise be higher. Because of the resulting high thermal load, the total time used for processing the product should be kept as short as possible, even if the product has been satisfactorily stabilized.

The casting mixture according to the invention constitutes a class of chemical substances which have the widest practical application. Examples include the production of plates, sections and pipes, especially for the building industry, where the high heat resistance temperature is particularly important. In this field, it is not only common to compensate

. for a degrading effect on the heat destruction temperature of PVC by using impact strength modifiers, but also the inclusion of polycarbonate opens up new areas of application for PVC and that:: the advantage of low price could not previously be used due to the low dimensional stability against heat. The material can also be used in the packaging industry in the form of bottles, containers and foils which, unlike PVC, can be brought into contact with hot contents. It is also

countless possible applications for the material in the form of injection-molded articles for special purposes, where extreme dimensional stability against heat is required in addition to high transparency. The high resistance of the casting mixtures to hydrolysis enables them to

used in the construction of chemical equipment as storage containers for acids, alkalis and ventilation systems for corrosive exhaust gases. In the electrical area, the material's high adaptation resistance comes into its own. The use of the material from dissolution in casting, spread coating or printing for the production of coatings or foils must also be mentioned as a possible use.

Examples:

To produce the casting mixtures mentioned in the examples, a stabilized polyvinyl chloride mixture is first prepared and then worked up into a homogeneous mass with the polycarbonate or other components on rollers. The individual products are manufactured as follows: A.. Polyvinyl chloride.

100 parts by weight of suspension polyvinyl chloride with a K value of 68 are mixed for 5 minutes in a high-speed mixer at 2,000 revolutions per minute. minute with the addition of a stabilizer system consisting of:

6.0 parts by weight of di-n-octyl-tin-dithioglycolic acid ester,

1.5 parts by weight of stearyl stearate,

1.0 parts by weight distearyl phthalate,

0.3 parts by weight montanic acid ester and

0.2 parts by weight polyethylene wax.

The temperature rises to 120°C. The mixture is then cooled to room temperature, while the speed of the mixer is reduced (approx. 500 revolutions/minute).

The resulting polyvinyl chloride mixture is found to have the following mechanical properties: Ball compressive hardness DIN 53 456 kp/cm<2>1317

.Impact strength DIN 53 453 cmkp/cm<2>

Room temperature 10 samples not broken

- 20°C 3/10 broken

- 40°C 42 Average impact strength DIN 53 453 cmkp/cm

Room temperature 2

Vicat DIN 53 460 °C l kp 86

5 kp 74 Bending strength DIN 53 452 950.

Tagging etc. 3.8

Tensile strength DIN 53 455 kp/cm<2>653

Extension DIN 53 455% 4

B. Polycarbonate.

Polycarbonate based on 2,2-bis-(3,5-dimethyl-4-hydroxy-phenyl)-propane in powder form. The relative viscosity is nrel=1.30 (determined on a solution of 0.5 g of the polycarbonate in 100 ml of methylene chloride).

CP Rubber modified resin I.

A graft polymer of 50 parts by weight polybutadiene, 36 parts by weight styrene and 14 parts by weight acrylonitrile.

D. Rubber modified resin II.

Grafting polymer of 30 parts by weight polybutadiene, 45 parts by weight styrene and 25 parts by weight methyl methacrylate.

Example 1.

80 parts by weight of polyvinyl chloride mixture A are first mixed with 20 parts by weight of polycarbonate B for one minute in a high-speed mixer at approx. 1500 revolutions/minute and then homogenized in a laboratory roller for a total of 5 minutes. The rolling temperature is 260°C. A continuous transparent sheet is obtained. This sheet is then preheated without pressure in a high pressure press at 210°C for 3 minutes and then pressed for a further 3 minutes under pressure to form a plate from which samples are formed. The plates that form are transparent. • Their mechanical data is listed in Table 1.

Example 2-5.

The mixtures are prepared from the following components as indicated in example 1:

Molding mixtures of high transparency are achieved in all cases. The mechanical properties are shown in table 1.

Example 6.

50 parts by weight of polycarbonate A are dissolved in methylene chloride and 50 parts by weight of suspension polyvinyl chloride with a K value of 68 are dissolved in cyclopentanone. The solutions are combined with stirring. The polymer mixture is carried out by introducing the solution dropwise into methanol. The finely divided polymer mixture is dried for 20 hours at 60°C and 15 hours at 80°C under vacuum.

In order to work up the product, 100 parts by weight of the precipitated polymer mixture with stabilizer and lubrication system specified in example 1 are mixed in a high-speed mixer as specified in example 1 and the resulting mixture is homogenized on a roller for 5 minutes at 240 DC. The formed rolled sheet is transparent and is processed into pressed plates as indicated above. The plates' mechanical properties are listed in table 1.

Example 7 - 12.

Polyvinyl chloride (A), polycarbonate (B) and resin (D)

. mixed by the procedure indicated in example 1:

The resulting casting mixtures are transparent and, in addition to the great hardness and flexible strength indicated above, they are distinguished by high toughness and shear strength. The mechanical properties are indicated in table 2.

Example 13 - 17-.

Opaque casting mixtures are prepared in the same way as in examples 7 - 12, but resin C is used:

. The mechanical properties are shown in table 3. -

Claims (11)

1. Polymer mixture, characterized in that it consists of: (a) from 20 to 90 wt%, based on the mixture of (a) and (b) of polyvinyl chloride or a copolymer of vinyl chloride with up to 30 wt%, based on the copolymer of at least one other copolymerizable vinyl compound; (b.) from 10 to 80% by weight, based on the mixture of (a) and (b), of a polycarbonate with at least 50% by weight of structural units of the following general formula (1): in which X means a single bond, -0-, -CO-, -SC^ -, C]_'"c1o alkyleneJ Cl~ Cl0 alkylidene> C5~ ci5 cycloalkylene, C^-C^ cycloalkylidene, C^ - <C>20 cycloalkyl-alkylidene or the group: and (c) from 0 to 100% by weight, based on the mixture of (a) and (b) of a rubber and/or a rubber-modified thermoplastic resin. 2. Mixture according to claim 1, characterized in that it consists of: (a) from 30 to 90% by weight of a vinyl chloride homo- or copolymer containing up to 30% by weight of at least one other vinyl compound; (b) from 10 to JO weight$ of polycarbonate corresponding to that gene real formula (2): where n means 30 - 100 or a polycarbonate having at least 50% by weight of structural units of formula (2), the remainder consisting of structural units of formula (2 a) and (c) from 10 to 50% by weight, based on the mixture of (a) and (b) of a rubber and/or a rubber-modified thermoplastic resin. 3. Mixture according to claim 1 or 2, characterized in that the polycarbonate (b) contains exclusively structural units of formula (1). 4. Mixture according to one of claims 1 to 3, characterized in that X means 5. Mixture according to one of claims 1 to 4, characterized in that up to 50% of the structural units of polycarbonate (b) are derived from the following bisphenols: 2,2-bis-(4-hydroxyphenyl)-propane 2, 2-bis-(3, 5-dichloro-4-hydroxyphenyl)-propane 2,2-bis-(3,5-dibromo-4-hydroxyphenyl)-propane 1.1- bis-(4-hydroxyphenyl)-cyclohexane a,a'-bis-(4-hydroxyphenyl)-p-diisopropylbenzene and 2.2-bis-(3-methyl-4-hydroxyphenyl)-propane. 6. Mixture according to one of claims 1 to 5, characterized in that component (a) has a K value of from 50 to 80. 7. Mixture according to one of claims 1 to 6, characterized in that component (a) contains up to 30 wt# of one or more of the following compounds: vinyl acetate, vinyl propionate, vinyl benzoate, acrylic or methacrylic acid esters containing 1 to 10 carbon atoms in the alcohol group, maleic acid esters or semi-esters, ethylene propylene, vinyl ethers, acrylonitrile, maleimides or vinylidene chloride. 8. Mixture according to one of claims 1 to 7, characterized in that the rubber-modified thermoplastic resins used therein are graft polymers produced by polymerization of styrene, α-methylstyrene, acrylonitrile, methacrylonitrile, acrylic or methacrylic acid alkyl esters containing 1-10 carbon atoms in the alcohol group or mixtures thereof in the presence of polybutadiene or copolymers of butadiene with styrene, α-methylstyrene, acrylonitrile, methacrylonitrile, acrylic or methacrylic acid esters containing 1-10 carbon atoms in the alcohol group. 9. Method for producing a polymer mixture according to claim 1, characterized in that the components (a), (b) and (c) are mixed. 10. Polymer mixture produced by the method according to claim 10 or 11. 11. Molded products made from a polymer mixture according to one of claims 1 to 8 or 10.