DE2944068A1 - FUEL-CONTAINING MOLDING MATERIAL WITH A POLYVINYL CHLORIDE BASED RESIN - Google Patents

Description

Molding compound containing blowing agent with a synthetic resin based on polyvinyl chloride

Field of application of the invention:

The invention relates to a blowing agent-containing molding compound with a synthetic resin based on polyvinyl chloride (PVC).

The molding compound is used to manufacture semi-finished products and finished molded parts made of a foam based on PVC.

The engineering synthetic resins based on PVC, which form one component of the molding compound, are hereinafter referred to as "PVC resin" for short. designated. This term includes both vinyl chloride homopolymers as well as polymers that are obtained by polymerizing a monomer mixture, which contains monomeric vinyl chloride as the main component.

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TELEPHONE: (089) 85O2O3O; 8574O80; (O6O27) 8825 TELEX: S 21 777 Isar d

QRlGWAL INSPECTED

Characteristics of the known technical solution ;

For the production of foams from PVC resins in the above four different methods are known in principle:

(1) The resin is made with a decomposable, so-called chemical propellant mixed or impregnated, whereby the chemical propellant develops with the development of the propellant serving gas chemically decomposed. The blowing agent-containing molding compound is processed with heating, for example by extrusion or injection molding. As a result of the heating, the molding compound is subjected to chemical decomposition foamed propellant gas formed by the propellant.

(2) By mixing the resin with a plasticizer, one is first commonly referred to as a "plastisol" PVC paste made. This plastisol is then processed into foam by mechanically mixing in air. Alternatively, a chemical blowing agent can also be added to the plastisol, if necessary in addition. Of the Plastisol foam is then processed while being heated, with the chemical blowing agent developing decomposed of the propellant gas. At the same time, the plastisol gels when heated.

(3) The molded parts are first formed from the molding compound containing a chemical blowing agent, for example i.e. panels, blocks, profile material or pipe material manufactured. The shaping can be done by rolling or any other mechanical shaping process. During the shaping processing, the temperature of the mass remains lower than the decomposition temperature of the chemical Propellant. Then the preformed mass is heated and the decomposition caused by it

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of the chemical blowing agent foamed.

(4) A molding compound is produced that contains a chemical blowing agent and, optionally, a physical one Contains propellant. In the usual way, a physical blowing agent is understood to mean a blowing agent, which is present in the molding compound in the liquid phase under storage conditions and when the molding compound is heated evaporated to form the propellant gas required for foaming the molding compound. Serves as a physical blowing agent in the context of the PVC foam molding compound discussed here an organic solvent in which the resin component is swellable. The molding compound also contains a plasticizer. The so composed molding compound is in a Metal mold filled and heated under pressure in the mold. The molding compound that melts and gels in the process is then cooled to room temperature in the mold under pressure. The molded part obtained in this way is then heated again to a temperature which is above the softening range of the resin component. The one formed by the chemical blowing agent and / or the vaporizing physical blowing agent that is decomposing in the process Propellant gases are then used for the final foaming of the molded part.

The propellant gas which is used to foam the molding compound and which is enclosed in the foam after foaming, is therefore in most cases atmospheric air that has been dispersed in the molding material, or Irish the gaseous decomposition product of a chemical blowing agent. A disadvantage of the mechanical incorporation atmospheric air in the molding compounds is that foams with a uniform, fine-pored cell structure and large Degrees of foaming are hardly obtainable even if complex mixers are used to incorporate the air,

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called gassing. The use of chemical blowing agents, however, is undesirable when the PVC foams should remain as white as possible. Most of the substances used as chemical blowing agents are Azo compounds that form colored decomposition products. This is caused by foaming with chemical blowing agents colored decomposition products, the foams produced in this way are colored yellow to brown. About that In addition, even when using chemical blowing agents, a homogeneously fine-pored solution cannot always be produced in the desired manner Product can be obtained. This is particularly problematic if the foaming causes a particularly large one. Volume enlargement is to be brought about, so in the area of high degrees of foaming.

In addition, the above-mentioned known methods (1), (2) and (3) are not highly suitable for production foamed rigid or semi-rigid foams. The processes mentioned are therefore relatively low-foamed in the area Flexible foams limited. In addition to the problems with the known foaming processes described above the known method (4) has the disadvantage of low production efficiency and thus high production costs on. The process must be carried out batchwise. Due to the complexity of the procedure a relatively long residence time is required for foaming. In addition, common methods are expensive Forming tools blocked for a relatively long time.

It is also known for gassing synthetic resin molds to use so-called physical blowing agents. Such physical blowing agents are low-boiling liquids, which evaporate rapidly when the molding compound in which they are incorporated is heated. If the temperature is on which the molding compound is heated above the softening range

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the synthetic resin component, the molding compound is foamed. The physical blowing agents stand out mainly because they do not form colored decomposition products when foaming, which the foams discolor. The foaming propellant gas is the physical propellants by evaporation and not by chemical decomposition formed.

Physical blowing agents are already used in a variety of ways to produce a wide variety of foams, for example for the production of polystyrene or polyurethane foams. The use of physical However, blowing agents for the production of PVC foams have not yet been used successfully been. Dlg causes the technical problems that the Use /, physical blowing agent for the production of PVC foams have hitherto prevented so far largely unknown.

GOAL of f He indung:

The aim of the invention is to create a blowing agent-containing molding compound for production-effective and inexpensive Production of practically undyed, highly expanded, homogeneous

Fei η por i ger PVC sc ha t o t t o t.

Explain the essence of the invention :

The invention is based on the technical problem, a to create blowing agent-containing molding compound with a synthetic resin based on PVC, which is highly expandable and as a blowing agent

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medium contains a physical blowing agent.

To achieve this object, the invention creates a blowing agent-containing molding composition which, according to the invention, has the im The characterizing part of claim 1 has specified features.

The molding composition of the invention is thus characterized by a resin component based on PVC with an average degree of polymerization of not greater than 2,000 and a pore volume of not greater than 0.20 ml / g in conjunction with a hydrocarbon serving as a physical blowing agent, or halogenated hydrocarbon with a boiling point of not greater than 90 ⁰ C, wherein the PVC resin component is impregnated with this physical blowing agent.

Such molding compounds can be foamed to form highly expanded foams which are characterized by a fine-pored and homogeneous foam structure or cell structure. With this basic formulation of the molding compound, high-quality, fine-pored and homogeneous foams with apparent densities down to 0.10 g / cm ³ , sometimes even less, are obtained.

Extremely highly expanded foams with a homogeneous fine-pored cell structure and an average apparent density of significantly less than 0.10 g / cm ³ can, according to one embodiment of the invention, be produced from a molding compound that is impregnated to 100 parts by weight of the physical blowing agent PVC resin contains 0.5 to 30 parts by weight of a pore control resin. An acrylic resin or a styrene resin is used as the pore regulator resin. The pore regulator resins preferably have a viscosity number, more precisely limiting viscosity number, of at least 3.0 dl / g. The influence of the pore regulator resin can be reduced by adding small amounts of a

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Nucleating agent to be improved to the molding compound. A finely powdered inorganic substance or serves as a nucleating agent a combination of solid reagents which, when reacted, can develop carbon dioxide in the molding compound.

The main component of the molding compound is a PVC resin in the sense defined at the outset. This PVC resin can do both a vinyl chloride homopolymer as well as a copolymer consisting at least essentially of vinyl chloride. If the PVC resin is a copolymer, the proportion of the monomer or monomers that is present with the vinyl chloride is are copolymerized, preferably in the range not exceeding 40% by weight, in other words that the PVC resin consists of at least 60% by weight of vinyl chloride assemblies. Foams with such a composite PVC resin are characterized by good flame resistance and good mechanical strength without affecting the other Characteristic good properties of vinyl chloride polymers be affected.

Ethylenically unsaturated monomers which can be polymerized with vinyl chloride are known from the prior art known per se. The following are preferred examples of such copolymerizable monomers: Vinyl esters, especially vinyl acetate and vinyl propionate; Vinylidenhdlogenide, especially vinylidene chloride and Vinylidene fluoride; other vinyl halides except vinyl chloride, especially vinyl fluoride; Acrylic acid and its esters, in particular ethyl acrylate; Methacrylic acid and their Esters, especially methyl methacrylate; Acrylonitrile; Methacrylonitrile; Maleic acid and its esters and its anhydride; Fumaric acid and its esters; as well as olefins, in particular Ethylene and propylene.

Among the above-mentioned comonomers is preferred

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especially vinyl acetate is used. Copolymers of vinyl chloride and vinyl acetate are not only particularly good and easily impregnated with a blowing agent, but also have a low melt viscosity, so that the The foaming process runs particularly evenly and results in foams with particularly fine-pored and homogeneous Cell structure leads. To these beneficial properties To bring the copolymer to full effect, the copolymer preferably contains at least 3% by weight vinyl acetate. As already stated in general above, the proportion of vinyl acetate should not be more than 40% by weight. A higher one Part by weight reduces the flame resistance and worsens the mechanical properties of those produced with such resins Foams.

The essential parameters for the invention and critical PVC resins used to produce the molding composition of the invention are the mean degree of polymerization and the Pore volume. The average degree of polymerization is determined in the usual way by measuring the viscosity of resin solutions certainly. For the PVC resin in the molding composition of the invention, the mean degree of polymerization is preferably not over 2,000, as a PVC resin with a degree of polymerization over 2,000 has an unusual melt viscosity and a has poor gelling behavior, so that highly expanded foams can hardly be produced with such resin components are, even if relatively large amounts of the physical blowing agent in the molding compound be incorporated. On the other hand is the limit of the smallest acceptable mean degree of polymerization determined by the mechanical properties expected of the foams made from such molding compounds will. For example, with PVC resins that have an average degree of polymerization of less than

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300, only quite brittle and mechanically unsatisfactory Get foams.

The pore volume of the PVC resin is also critical in the context of the invention. This pore volume "is not greater than 0.02 ml / g, preferably not greater than 0.10 ml / g. These values for the pore volume are unusually small compared to conventional PVC resins, which, for example in the case of a vinyl chloride homopolymer, have a value of at least about 0.25 ml / g the value of the pore volume is determined silberdruckporosimeter with mercury, said mercury -. "- pressure from 1 bar to 100 bar is increased. Under this pressure, the mercury is also pressed into those pores of the resin whose pore diameter is in the range of 30 (in or below.

The limitation of the mean pore volume is therefore of crucial importance, since the PVC resins at larger pore volume have insufficient retention capacity for the propellant. The propellant can escape under these circumstances not only during storage of the molding compound, but also especially during the Shaping, so that particularly strongly foamed molded parts can hardly be produced.

PVC resins that meet these two critical parameters can be prepared by suspension polymerization of monomeric vinyl chloride or a monomer mixture which consists essentially of monomeric vinyl chloride. The suspension polymerization is carried out in a customary manner in an aqueous medium in the presence of a suspending agent and a radical polymerization initiator soluble in the monomer phase.

The physical blowing agent, with the PVC resin that the

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_η3 294-068

, The physical blowing agent with which the PVC resin having the critical parameters described above, is soaked, as already mentioned, a hydrocarbon or a halogenated hydrocarbon having a boiling point of not more than -90 ⁰ C, preferably not more than 70 ^Q C lies. If the boiling point of the blowing agent is above 90 ^° C., the foams obtained show considerable shrinkage after foaming and leaving to stand, so that the foamed moldings obtained receive a cell structure which meets the requirements neither in terms of their homogeneity nor in terms of their fine pores.

As hydrocarbons and halogenated hydrocarbons, which are preferably used as physical blowing agents for the molding composition of the invention are as follows named: propane, butane, isobutane, pentane, neopentane, n-hexane-isohexane, n-heptane, methyl chloride, methylene chloride, chloroform, Carbon tetrachloride, ethylidene chloride, ethylidene fluoride, Trichlorethylene, 1,2-dichloroethane, trichlorofluoromethane, Dichlorodifluoromethane, chlorotrifluoromethane, bromodifluoromethane, Tetraufluoromethane, dichlorofluoromethane, chlorodifluoromethane, Trifluoromethane, trichlorotrifluoroethane, dichlorotetrafluoroethane, Dibromotetrafluoroethane, chloropentafluoroethane, Hexafluoroethane and 1-chloro-1,1-difluoroethane. These and other hydrocarbons and halogenated hydrocarbons used as physical blowing agents can be used alone as well as in a mixture of two or more together.

The amount in which the PVC resin is impregnated with the physical blowing agent mentioned depends on the increase in volume that is to be achieved during foaming. Of course, the proportion of propellant must be increased if there is a relatively large increase in volume,

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that is, a high degree of foaming should be achieved. If only a low degree of foaming is desired, three% by weight of the blowing agent incorporated into the resin component can be sufficient. The proportion of the physical blowing agent in the molding composition is typically in the range from 1 to 30% by weight. With such proportions of blowing agent, foams corresponding to the various conditions of use are obtained.

The impregnation or impregnation of the PVC resin component with the physical blowing agent takes place in principle in such a way that the two components are brought into intimate contact with one another. In particular, the PVC resin is usually in the form of a powder and in this form can simply be mixed or made into a paste with the blowing agent, the floating agent being absorbed by the resin particles. When the propellant is present as a gas or vapor at room temperature and under atmospheric pressure, the PVC resin, water and a dispersant are placed in a pressurizable vessel, for example an autoclave , which is equipped with a stirrer and a suspension of the resin powder in the aqueous phase is able to produce. The propellant is then pressed into the suspension with continued stirring, the temperature being increased to 30 to 90 ^° C. for 3 to 20 h. After equilibrium has been established in the pressure vessel, the mixture is cooled to room temperature. The resin, which contains the propellant absorbed, is discharged from the pressure vessel and dewatered in a suitable manner, preferably by centrifugation, and dried at a relatively low temperature. The impregnated PVC resin is preferably dried at 50 ^° C. or below.

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The blowing agent-impregnated PVC resin obtained in this way can be prepared as such by processes known per se are processed into molded foam parts, for example by injection molding or extrusion, but also by compression molding. The shaping takes place in one Metal mold in which the propellant impregnated resin, i.e. ^ i so, the molding compound, gelled and is foamed at the same time by the evaporating blowing agent. Before this processing, the molding compound can optionally are mixed with other conventional additives, for example with plasticizers, fire retardants, antioxidants and antistatic agents. The additives must be incorporated at sufficiently low temperatures in order to achieve a prevent premature evaporation of the physical propellant.

The technical problem in the production of PVC foams lies in ensuring a fine-pored foam structure or cell structure with a homogeneous pore distribution. This applies in particular to PVC foams which are highly foamed and have effective densities in the range of less than 0.10 g / cm ³ , without, however, wishing to say that the molding composition of the invention is not also suitable for foams with medium effective densities in the range of about 0.30 g / cm ³ and above leads to improved results. In particular, however, in the production of heavily foamed foams, the foam structure can be further improved by incorporating a pore regulator into the molding compound. According to one embodiment of the invention, this pore regulator is preferably a thermoplastic synthetic resin.

Resins based on acrylic acid or acrylate and based on styrene are preferably used as pore regulator resins. These resins are particularly effective when they have a

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Have viscosity number of at least 3.0 dl / g, measured in a chloroform solution at a concentration of 0.1 g / 100 ml and a temperature of 25 ⁰ C. These pore regulator resins are the PVC resin impregnated with the physical blowing agent in a Amount of 0.5 to 30 parts by weight per 100 parts by weight of PVC resin, namely in the form impregnated with the blowing agent and before the resins are shaped.

Either a polymethyl methacrylate or a copolymer is preferably used as the acrylic resin as the pore regulator resin, which consists essentially of methyl methacrylate and one or more acrylic acid esters, for example Methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate or 2-ethyl acrylate. The acrylic resin can be used in addition to the the above-mentioned comonomers also contain other comonomers, for example styrofoam, acrylonitrile, vinyl ester or esters of methacrylic acid other than methyl methacrylate, in particular ethyl methacrylate, n-butyl methacrylate or 2-ethylhexyl methacrylate. The prerequisite is that the Keeps proportion of these comonomers within the specified limits. In any case, the methyl methacrylate content is im Acrylic resin preferably in the range of 60 to 90% by weight.

The acrylic resin used as the pore regulator resin preferably has a viscosity number of at least 3.0 dl / g, preferably at least 5.0 dl / g, measured in chloroform in a concentration of 0.1 g / 100 ml at 25 ^° C.

It is preferable to use an acrylic resin having a higher viscosity number, in other words, having a higher average viscosity Degree of polymerization, used when the mean degree of polymerization of the PVC resin used is very large and approaches the upper limit of the value 2,000. Farther an acrylic resin is preferably used, which by

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Emulsion polymerization of the acrylic monomers produced became. The reason is that the use of such resins provides additional improvement in filling the molding compounds in the molds is achieved that the risk of clogging of the sprues is reduced, that the uniform gelling of the molding compound is accelerated and that the gelled and molten molding compound is stronger is expandable.

The acrylic resin used as the pore control resin is preferred to the PVC resin impregnated with the blowing agent in an amount of 0.5 to 30 parts by weight, particularly preferably in an amount of 3 to 20 parts by weight, each 100 parts by weight of the PVC resin were added. With higher proportions of the acrylic resin, no further improvement is achieved, while instead other properties of the PVC resin are adversely affected, especially the flame retardancy.

Another group of pore control resins to be added to the resin are synthetic resins based on styrene. Such styrene-based resins, "styrene resins" for short, include both homopolymeric polystyrene and copolymers consisting essentially of styrene which contain smaller proportions of acrylonitrile as a comonomer. In addition, the styrene copolymer can contain one or more further comonomers which can be copolymerized with styrene or acrylonitrile. In any case, however, the styrene resin has a viscosity of at least 3.0 dl / g, measured in chloroform at a concentration of 0.10 g / 100 ml and at a temperature of 25 ⁰ C. Preferably, the Styrciharz has a viscosity number which is as high as possible when the PVC resin has a high degree of polymerization, which is in the region of the upper limit of 2,000.

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The above with the styrene and the acrylonitrile copolymer Isable comonomers are preferably the following: methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, 2-ethylhexyl acrylate and others, esters of methacrylic acid, in particular methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, 2-ethylhexyl methacrylate and others, maleic acid and fumaric acid and their esters, and maleic anhydride.

The styrene resins named above are produced by polymerization processes known per se, however, they are preferably produced by emulsion polymerization in an aqueous medium.

The styrene resin used as the pore regulator resin is preferably added to the molding compound in the same amount as the corresponding amount Acrylic resins are added, i.e. in an amount of 0.5 to 30 parts by weight, preferably particularly 3 to 20 parts by weight, per 100 parts by weight, of the PVC resin impregnated with the physical blowing agent was added.

The mechanism that is responsible for the significant improvement of the cell structure or the foam structure in the obtained Foams can be achieved by adding the pore control resins, is probably due to that the gelling of the PVC resin is accelerated by the addition of the pore regulator resin and at the same time the melt viscosity of the PVC resin in the molding step is effectively controlled or increased so that the quantitative foamability of the mass is improved and the cell walls of the foam are reinforced and thereby provide improved resistance to foam collapse and shrinkage. This influence is particularly evident in the case of higher

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Temperatures noticeable, and also the ability to hold back the evaporating propellant, so the propellant inclusion, can be improved.

The foam conditioning brought about by the addition of the pore regulator resins can be further improved by using certain nucleating agents in the molding compound can be added with the pore regulator resins. Such nucleating agents which are preferably used in the context of the invention are fine-powdered inorganic substances, preferably calcium carbonate, talc, barium sulfate, fumed silica, Titanium dioxide, clay, aluminum oxide, bentonite and diatomaceous earth, these substances being a medium one Particle diameters of 30 µm or smaller, preferably 10 µm or smaller. The larger the mean diameter of the particles of these inorganic powdery additives is, the stronger the fluidity of the molten one becomes Resin affected during the molding process. This leads to the fact that the surfaces of the foam moldings, which were produced with the addition of such coarser powdery additives, lose their shine and sometimes streaky will. In addition, such molding materials have a less homogeneous cell structure.

Another class of nucleating agents is a combination of approximately equivalent amounts of an acid, for example Boric acid or an organic acid, in particular citric acid, tartaric acid or oxalic acid, and a carbonate or hydrogen carbonate with the cations sodium, potassium or ammonium, i.e. from sodium carbonate, sodium hydrogen carbonate, Potassium carbonate or ammonium hydrogen carbonate.

The nucleating agent is the molding composition in an amount of 0.01 to 20 parts by weight per 100 parts by weight of the with the

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Propellant added to impregnated PVC resin. If more than 20 parts by weight of nucleating agents are added, takes the increase in volume that can be achieved with foaming the molding compound. The foam molding obtained has poorer properties overall, in particular a less smooth and attractive surface.

Optionally, the molding composition of the invention can also be combined with a known and customary one chemical propellants are added, as long as its addition is limited in terms of quantity, preferably to about 5% by weight, preferably less than 5% by weight, based on 100 parts by weight of the physical Propellant impregnated PVC resin. The chemical blowing agent can preferably be one or more The following substances can be used: azo compounds, preferably azodicarboxamide, azobisisobutyronitrile, Diazoaminobenzene, diethyl azodicarboxylate, diisopropyl azodicarboxylate and other; Nitroso compounds, preferably N, N'-dinitrosopentamethylenetetramine, N, N'-dimethyl ! ■], N'-dinitrosoterephthalamide and others; as well as sulfonyl hydrazides, preferably benzenesulfonyl hydrazide, toluenesulfonyl hydrazide, 4,4'-oxy-bis (benzenesulfonyl hydrazide), 3,3'-di- (sulfonhydrazidphenyl) -sulfone, toluene disulfonylhydrazone, Thio-bis- (benzenesulfonylhydrazide), toluenesulfonyl azide, Toluenesulfonylsemicarbazide, 4,4'-oxybis- (benzenesulf onylhydrazide) and others, as well as sodium hydrogen carbonate.

The use of this chemical blowing agent is used for further improvement of the fineness and uniformity of the ZcI1 structure of the foams and the reduction the shrinkage of the foam moldings produced from such molding compounds, so that the intended shape of the Foam molded parts is better adhered to. A crowd

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However, a moderately large proportion of the chemical blowing agent is undesirable, since otherwise discoloration of the foam due to the colored decomposition products of the chemical blowing agent and a roughening of the surfaces of the molded foam parts occur without further improvement in the intended sense being achieved. It will if a chemical blowing agent is added, preferably a known one, the decomposition of the chemical one Propellant-promoting auxiliary added, a so-called promoter, preferably certain zinc compounds or copper compounds, which accelerate the decomposition of the chemical blowing agent and the evolution of gas trigger at a temperature that is lower than that during the shaping processing of the Molding compound is the temperature applied.

Molding compositions, the pore control resins in the manner described above are for the production of PVC foam molded parts mainly because they are highly expanded foams with a fine-pored structure and homogeneous cell structure, regardless of the rigidity set for the foam molding or hardness of the material. The material can be a soft foam or a hard foam or any intermediate hardness settings. The foams can also be used with the addition of Pore regulator resin according to any method known per se, in particular also continuous shaping method are produced, in particular by extrusion, injection molding or compression molding, without additional cost-increasing measures are required.

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Embodiments :

The invention is explained in more detail below on the basis of exemplary embodiments. The amounts given in parts below are parts by weight. The amount of physical blowing agent absorbed in the PVC resin and the pore volume of the resin are determined in the manner described below.

Determination of the amount of physical absorbed in the PVC resin Propellant:

The PVC resin impregnated with the physical blowing agent is heated ^{to 130 ° C. in a hot air oven for 2 h.}

From the weight W. before heating and the weight W-, after heating the impregnated resin, the percentage becomes

Degree of impregnation by the expression

(W ₂ - W ₃ ) W ₂ χ 100 (%) determined.

Determination of the pore volume in the PVC resin:

The pore volume is determined in a mercury pressure porosimeter of conventional design, the mercury pressure is increased from 1 bar to 100 bar. The measured values are given in the dimension ml / g, based on the resin.

Example 1 (experiment no . \ Up to 13)

A 5 liter autoclave with a stirrer is filled with 1,000 g of a vinyl oride homopolymer or a copolymer Vinyl chloride and vinyl acetate of the type and composition given in Table 1, where P is the average degree of polymerization and Vp is the pore volume in the resin, 2,000 y of purified water and 150 g of trichlorofluoromethane

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and 200 g of butane charged under pressure. The temperature in the reaction mixture is then increased to 70 ^° C. with stirring and kept at this temperature for 8 h with constant stirring. The resin is impregnated with the trichlorofluoromethane and butane, which serve as physical blowing agents.

The degree of impregnation is determined immediately after the production of the resins impregnated in this way with the physical blowing agent and after storage at 20 ^° C. for 1 week. The results obtained are summarized in Table 1.

100 parts by weight of the impregnated resin thus produced are mixed with 2 parts by weight of a tin-containing stabilizer and 1 part by weight of calcium stearate mixed. The molding compound obtained in this way is turned into one on an extruder extruded cylindrical foam strand material.

The (effective or apparent) density of the foam molding produced in this way is determined and is for each individual experiment is also given in Table 1.

The molding compound is extruded under the following conditions:

Screw diameter 20 mm

Screw length 400 mm

Compression ratio of the screw 3.0

Extruder head 5 mm in diameter

the outlet opening at an axial length of the shaping section of 70 mm

Sieves 0.175 mm and

0.147 mm clear _ΑΛΛΛ mesh size

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^C 1 = 60 until 1 20 ⁰ C ^C 2 = 100 until 160 ° ^C 3 = 120 until 180 ° approx . 1 30 ⁰ C 50 m in

Temperature of the cylinder sections

Temperature of the extruder head speed of the screw

The foam molding obtained in Experiment No. 9 is particularly brittle. The foam part obtained in experiment no. 11 shows a high degree of expansion on, but is unsatisfactory in its flame retardancy

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Table 1

Attempt no. Vinyl-
acetate-
proportion 1
(Wt .- *) 1 2 3 4th 5 6th 7th 8th 9 10 11 12th 13th • y
-ν PVC
resin P. 5 10 12th 0 20th 30th 40 40 10 5 45 3 0 Vp (ml / g) 350 400 520 700 800 1,000 1,300 1,800 2 70 2,500 810 700 1,000 :> fresh
here
represents 0.009 0.010 0.009 0.035 0.015 0.020 0.080 0.12 0.010 0.20 0.020 0.25 0.35 j *
O
κ » Up
taken
Drive
middle
(Wt%) To
1 week
at
20 ⁰ C 8.0 10.1 11.0 9.4 9.5 7.5 7.0 7.5 9.0 7.4 9.5 1.9 Foam
density (g / ml) 7.5 9.4 30.4 8.5 8.8 7.0 6.5 6.0 8.0 5.6 8.5 0.8 0.3 0.073 O, O65 0.060 0, 19 0, 11 0.21 0.23 0.25 0.14 1.35 0.10 1.2 1, 35

2944063 ZC

Example 2 (experiments no. 14 to 26)

The autoclave also used in Example 1 is mixed with 1,000 g of a copolymer, 2,000 g of purified water, 1.0 g of partially saponified polyvinyl alcohol and 2 different physical blowing agents, the type and amount of which are specified in Table 2. The copolymer consists of 88% by weight of vinyl chloride and 12% by weight of vinyl acetate and has a pore volume Vp of 0.010 ml / g and an average degree of polymerization P of approximately 650. The physical blowing agents are, if necessary, introduced into the autoclave under pressure. After charging, the mixture is ^{stirred at 70 °} C. for 8 h. The blowing agent is absorbed by the resin component.

Table 2 shows the physical blowing agents used given in the following nomenclature, this nomenclature also being used in all of the following tables and Examples is used.

PR: propane

PE: pentane

HE: n-hexane

TCFM: trichlorofluoromethane

MC: methyl chloride

Caption: butane

MEC: methylene chloride id

DCTFE: dichlorotetratluoroethane

DCDFM: dichlorodifluoromethane

DCFM: dichlorofluoromethane

TCE: 1,1,2-trichloroethane

TCDFE: tetrachlorodifluoroethane

ISO: isooctane

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The amount of blowing agent absorbed by the resin and the effective density of the foam test specimen that
is produced as a cylindrical strand material in the manner described in Example 1, In the
Table 2 compiled- The foam specimens
of tests Nos. 24 to 26 show severe shrinkage after shaping.

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Table 2

Attempt no. 14th 1Γ) 16 17th 18th 19th 20th 21st DCTFE
(1 00)
'IClM
(200) 23 24 25th 26th α propellant
ο (g)
ο PK
(300) PE
(300) HE
(300) TCFM
(300) MC
(200)
4-
PE
( 200) BU
(300) BU
(200)
MEC
(1 00 y ¹ ICFM
(200)
PE
(200) 20.4 DCDFM
(150)
DCFM
(15U) TCE
(2O0) TCl) FE
(200) ISO
(2U0) ~~ * Recorded
_o Propellant
a lot
^ (Wt%) 8.1 8.5 10, 2 19.0 20, 1 10.5 14.7 18.3 0.09 18, 1 11.0 10.2 7.9 Foam
elights
(g / ml) O, 1 3 j
0, 1 3 i
0.24
i C), 09 0.13 0, 10
i 0.07
I. 0.08 0.09
I. 0, 7 ^r ) 0.80 0, 8 7

29U068

Example 3 (experiments No. 27 to 33)

A 100 l autoclave made of stainless steel and equipped with a stirrer is also used in Example 2 with 30 kg Vinyl chloride-vinyl acetate copolymer, 50 kg of purified water and 15 g of a partially saponified polyvinyl alcohol loaded. A mixture of butane and trichlorofluoromethane is then used as a physical blowing agent under pressure Weight ratio 2: 1 abandoned. The amounts of propellant injected are for each individual experiment in the Table 3 named. This is followed by 8 h with stirring at the temperature likewise given in the table warmed up. The blowing agent is absorbed by the resin. The dehydration and drying of the resin impregnated with the blowing agent is carried out in the manner described in Example 1 Way. The amount of blowing agent absorbed by the resin under these conditions is also given in the table shown.

100 parts by weight of the resin impregnated with the blowing agent, 2 parts by weight of a tin-containing stabilizer and 1 part by weight of calcium stearate are mixed to form a molding compound. The molding compound is processed into a foam sheet by extrusion. The test specimens obtained in this way are used to measure the effective density, the thermal conductivity at 20 ^° C. (according to the regulations of the Japanese industrial standard JIS A 1413) and the compressive strength at 20 ^° C. (according to the test regulations of the US industrial standard ASTM D 1621). The results obtained are summarized in Table 3.

030021/0692

The conditions under which the test specimen is extruded are summarized below:

Diameter of the screw Length of the screw

Compression ratio the snail

jet
Sieves

Cylinder temperature

Temperature of the nozzle speed of the screw 6 5 mm 1,300 mm

2.0

100 mm wide and 8 mm high

1 sieve with a mesh size of 0.175 mm and 1 sieve with a mesh size of 0.147 mm

C ₁ = 80 ⁰ C C = 120 ⁰ C

C ₃ = 150 ^° C 120 ^° C

30 min

-1

0 3 0 0 2 1/0602

Table 3

Attempt no. ( ⁰ C) 27 28 29 30th 31 32 33 0.95 45.00 Amount of propellant added
I (kg) ne propellant
(Wt%) 3 6th 8th 11 6th 6th 0.6 I.
0.142: 0.419 ^: Temperature
Recorded
lot
: density 70 70 70 70 35 85 70 0.7 8 t
Ϊ
i
Own
societies
I.
of
! Show
I fabric
i Thermally conductive
speed (kJ / 'm · h · ⁰ C) to
5.0 8.2 12.1 13.3 9.1 10.9 0.8 Compressive strength
(N / mm ² ) 0.18 0.080 0.059 0.058 0.070 0.061 0.180 0.155 0.147 0.130 0.147 3.9 0 1.1 2 0.6 0 0.6 3 0.9 3

CZ) CJ)

Example 4 (experiments nos. 34 to 43)

Following the procedure described in Example 1, a vinyl chloride-vinyl acetate copolymer is impregnated with a physical blowing agent which is a mixture of trichlorofluoromethane and butane. The proportions of vinyl acetate in the copolymer, the average degree of polymerization P and the pore volume Vp are given in Table 4. The amount of the blowing agent taken up is measured immediately after the production of the resin impregnated with the physical blowing agent and after a storage time of 1 week at 20 ^° C. These data are also given in Table 4.

Expandable molding compositions are made by mixing 100 parts by weight of the above-prepared copolymer resin impregnated with the physical blowing agent, 2 parts by weight of a tin-containing stabilizer and 1 part by weight of calcium stearate; Part of talc as a nucleating agent, 1 part by weight of a commercially available azodicarboxamide as a chemical blowing agent and one of the acrylic resins E-1 or E-2 in the amounts shown in Table 4.

The acrylic resins E-1 and E-2 used as the pore control resin are the following:

EI: A copolymer which consists of 90 wt .-% of methylmethacrylate and 10 parts by weight ό ethyl acrylate and 0.1 g / 100 ml has a viscosity of 10 dl / g at 25 ⁰ C and in a chloroform solution.

E-2: A commercially available acrylic resin.

D30G21 / 0692

The expandable molding compounds produced in this way are shaped into molded foam parts by extrusion. It will the same extruder is used as in Example 1 and the same extrusion conditions are observed. To the so obtained foam specimens are the density and the Checked cell structure. The results are shown in Table 4. This is the assessment of the customs structure made in the table according to the following criteria:

Cell structure A: pore diameter not larger than

500 μΐη

Cell structure B: pore diameter in the range from 500 to

2,000 um.

The foam test specimen obtained in Experiment No. 40 showed a remarkable fragility. In experiment no. 43, the molding compound foams too early, with foaming begins in the extruder head. This leads to the formation of flow patterns on the surface of the foam molded part.

030021/0692

Table 4 - 1

Attempt no.

PVC resin

vinyl acetate content (% by weight)

Aufgenoni-

! Vp (ml / g)

freshly made

mene driving- ——, ---, · ■ ,,, After 1 week

: ii qty
(Ce w. -I)

Nucleating agents

C r. <: ■ m. ' i ¹ rub in i 11 e 1

at 20 ^° C

Acrylic resin (weight toile)

ichaum-
; tof f

density

Cell structure

35 36 37 38 12th 5 20th 30th 520 350 700 1000 0.010 0.009 0.012 0.020 11.0 8.0 10.3 7.5 10.3 7.4 9.7 7.0 with
with with
with with with E-1
(10.0) E-2
(6.0) with with O _; O45 0.050 E-2
(6.0) E-2
(6.0) 34 A. A. 0.051 0.10 12th A. A. 520 0.010 I I, 0 10.3 with
without E-1
(ιο, ο) 0.050 A.

030021/0692

Table 4-2

39 40 41 42 43 40 10 30th 2 45 .1300 270 1600 800 810 0.023 0.010 0 _; 050 0.060 0.020 7.0 9.0 6.0 6.9 9.5 6.6 8.0 4.0 5.4 8.5 with without without without with with without without without without E-2
(6.0) without without without without 0.20 0.14 0.30 0 _; 23 0.11 A. B. B. B. B.

030 021/0692

£ 2944063

Example 5 (experiments nos. 46 to 56)

The autoclave also used in Example 4 is filled with 1,000 g of the vinyl chloride-vinyl acetate copolymer also used in Example 2, 2,000 g of purified water and 1 ″, 0 g of a partially saponified polyvinyl alcohol and one or a mixture of two different physical blowing agents in the in The method specified in Table 5 is charged, and after charging is complete, the mixture is ^{heated for 8 hours with stirring to 70 °} C. The resin absorbs the propellant or propellant mixture.

From the resin thus produced and impregnated with the blowing agent, an expandable molding compound is produced by that 100 parts by weight of the copolymer impregnated with the physical blowing agent, 1 part by weight (experiments 46 to 48) or 3 parts by weight (experiments 4 9 to 56) of a nucleating agent of the type specified in detail in Table 5, if appropriate mixed with the further addition of 6 parts by weight of acrylic resin as a pore regulator resin.

The nucleating agents used in these experiments are as follows:

Orbs: An organic complex of a colloidal

hydrated aluminum silicates with an average grain size of approximately 0.5 μm;

Hakuenka O: a calcium carbonate filler L with a

mean particle diameter of 0.02 to 0.03 μίτι;

03002 1/0692

Titanium dioxide A-100:

a filler grade titanium dioxide with an average particle diameter in the range from about 0.15 to 0.2 5 μΐη;

Aerosil 200; a fumed silica filler having a specific surface area of about 200 m ² / g and an average particle diameter of about 0.012 µm;

Aerosil 328, a fumed silica filler with a specific surface area of approx. 380 m ² / g and an average particle diameter of approx. 0.002 μm;

an alumina filler with an average particle diameter of about 0.005 to 0.02 μm;

Barium sulfate # 100:

a commercial product with an average particle diameter of approximately 0.6 μm;

Satenton No. 5:

a commercially available clay product and

3S valley:

a commercially available talc product.

The expandable foam molding compositions produced in this way become a cylindrical foam strand material extruded. The extruder also used in Example 4 is used under the same extrusion conditions.

030021/0 6 92

The density of the foam test specimens obtained measured. The results are summarized in Table 5.

Table 5-1

j attempt no.
I. 46 47 48 49 50 j physical
! Propellant
I.
j (g)
i PR
(300) PE
(300) TCFM
(300) BU
(300) BU
(200)
+
MEC
(100) Recorded
Amount of propellant
(Wt%) 6.5 7.0 15.4 7.3 11.0 Nucleating agents Orbs Orbs Haku-
enka 0 Titannium
Dioxides
A-100 Aerosil
200 Chemical propellants without without without without without Acrylic resin with with with with with Density of the foam
substance (g / ml) 0.089 0.093 0.077 0.080 0.039

030021/0 6 32

it

Table 5-2

51 52 53 54 55 56 ' TCFM
(200)
+
PE
(100) TCFM
(30)
+
BU
(30) TCFM
(100)
+
BU
(100) TCFM
(200)
+
BU
(400) TCDFE
(200) ISO -
(200) 12.4 8.2 15.0 9.8 7.4 Al ₂ O ₃ C barium
Sulfates
# 100 Talc
3S Saten -
volume
No. 5 Aerosil
380 Haku-
enka 0 with with with with with with with with with with with with 'O, O59 0.15 0 _; 073 0.030 0.70 0.81

030021/06

tv

Example 6 (experiments No. 58 to 71)

A 100 1 stainless steel autoclave equipped with a stirrer is filled with 30 kg of a copolymer consisting of 88% by weight vinyl chloride and 12% by weight vinyl acetate and with an average degree of polymerization P of approximately 850 and a pore volume Vp of 0.015 ml / g , 50 kg of purified water, 15g of a partially saponified polyvinyl alcohol and 6 kg of trichlorofluoromethane and 3 kg of butane charged under pressure. The mixture is then ^{heated to 70 °} C. for 8 h with stirring. The trichlorofluoromethane and butane, which serve as physical blowing agents, are absorbed by the resin. After completion of the impregnation and cooling to room temperature, the unused propellant is discharged. The impregnated resin is then dewatered in the centrifuge and then ^{dried at 40 to 50 °} C. in a stream of warm air. A resin is obtained which is impregnated with 11.8% by weight of blowing agent.

An expandable molding compound is prepared by mixing 100 parts by weight of the with the physical Propellants impregnated copolymer, 2 parts by weight of a tin-containing stabilizer and 1 part by weight of calcium stearate, possibly of additional talc (except in Experiment no. 62) in the amounts given in Table 6 or a combination of 0.5 part by weight of sodium hydrogen carbonate and 0.4 parts by weight of citric acid (Experiment No. 62) as a nucleating agent, a chemical blowing agent and a Acrylic resin as a pore regulator resin in the type and amount specified in Table 6.

The following abbreviations are used in Table 6 for chemical blowing agents and acrylic resins:

030021/0692

294 4th floor 8

AIBN: α, ο'-azobisisobutyronitrile PTS: p-toluenesulfonyl hydrazide

OBS: 4,4 * -oxy-bis- (benzenesulfoniyhydrazide)

DNM: dinitrosopentamethylenetetramine

Celmic 133: also in Example 4 as a chemical

Propellant used commercially available azodicarboxamide
E-3: a copolymer consisting of 80% by weight

Methyl methacrylate, 10% by weight butyl acrylate and 10% by weight ethyl acrylate with a viscosity number of 5.5 dl / g at 25 ^° C.

E-4: a copolymer of 85% by weight methyl methacrylate and 15% by weight butyl acrylate with a viscosity number of 5.0 dl / g at 25 ^° C. E-5: a commercially available acrylic resin E-6: also an im Commercially available acrylic resin

The molding compounds specified in Table 6 are used with the extruder also used for the experiments in example 3 formed into foamed sheets under the same conditions. On the foam test specimens produced in this way the density, the cell structure, the appearance, the compressive strength and other mechanical data as well as the thermal conductivity certainly. The compressive strength is determined in accordance with the US test standard ASTM D 1621. The measurement of the thermal conductivity is carried out according to the test specification in the Japanese industrial standard JIS A 1413. The results are summarized in Table 6.

In experiments nos. 70 and 71, foaming of the molding compound occurs too early, namely at a point in time at which the Molding compound is still in the extruder nozzle channel. The test specimens show broken foam structures and point flow marks on the surfaces. Also, the appearance of the test piece obtained after Experiment No. 69 was not

030021/0692

satisfactory. The cell structure of the substances under test is fully satisfactory except for the specimens obtained after tests 68 and 69. After trying No. 68 obtained foam specimen leaves the uniformity the cell structure leaves much to be desired.

030021/0692

29Λ4063

Vi

Table 6-1

Attempt no. density
(g / ml) 58 59 60 61 62 Nucleating agents
(Parts by weight) Compressive
speed
(N / mm ² ) 1.0 1.0 1.0 1.0 (see Tex Chemical propellants
(Parts by weight) Flexural strength
speed
(N / mm ² ) AIBN
(1.0) PTS
(1.0) OBS
(1.0) DNM
(1.0)
+
urea
(1.0) Celmic
133
(1.0) Acrylic resin
(Parts by weight) Tensile strength
speed
(N / mm ² ) E-3
(5.0) Me ta-
blen
P 501
(5.0) E-4
(5.0) E-5
(1.0) E-5
(20) Own
societies
of
foam Thermal conductivity
capability
(kJ / mh- ° C) 0.034 0.035 0.035 0 _t 030 O _f O33 fabric 0.3 3 0.3 5 0.3 5 I (3 0 0.3 4 0.5 1 0.5 4 0.5-4 D48 0.5 3 0.5 0 0.5 2 0.5 3 ), 4 8 0.5 1 0.105 0.109 0, 109 0.105 0.117

030021/0692

29A4068

Table 6-2

1.0 0.005

Celmic Celmic without I 133. ] 33

(8.0) (1.0)

elmic Celmic without I _l3 3 (0.5) E-3 j E-3 _x (5.01 (0.3)

(Ϊ0) I C5.0)

E-5 lE-5

(30) (0 0.8 β 1.3 0 2p 1

0 7 8 0 5

D ₁ 6 7 11.6 1.6 8

0.130 0.155

, 117 0.113

030021/0692

ORIGJNAL INSPECTED

2944063

7 ·

Example 7 (experiments no. 72 to 92)

A 5 l autoclave made of stainless steel equipped with a stirrer is filled with 1,000 g of a homopolymeric polyvinyl chloride or a vinyl chloride-vinyl acetate ^ copolymer of the composition given in Table 7, 2,000 g of purified water and one or two different physical blowing agents, which are also shown in Table 7 specified type and in the quantities specified there, if necessary under pressure. ^{The mixture is then heated to 70 °} C. for 8 h with constant stirring. The resin component absorbs the physical blowing agent. After completion of the impregnation and cooling to room temperature, the excess blowing agent is discharged, the impregnated resin is separated from the aqueous phase by filtration and then ^{dried in a stream of warm air at 40 to 50 °} C. for 5 hours. A resin impregnated with the physical blowing agent is obtained, the characteristics of which are shown in Table 7. The impregnated resins obtained in this way are stored ^{at 20 ° C. for 1 week.} After this storage time, the loss of propellant is measured. The propellant losses are relatively uniform in the range from 6 to 9% by weight for each of the test substances.

Using the resins impregnated with the blowing agent in this way, an expandable molding compound is produced by mixing 100 parts by weight of the resin impregnated with the blowing agent or agents, 2 parts by weight of a tin-containing stabilizer and 1 part by weight of calcium stearate, optionally with additional Admixture of a nucleating agent, a chemical blowing agent and an acrylic resin, namely the acrylic resin E-1, as a pore regulator resin. The individual formulations can be found in Table 7. From the so by mixing the Components produced molding compounds are foam test specimens

030021/0692

-Jf-

produced by extrusion in the form of cylindrical strand material. When extruding the following parameters adhered to:

Screw diameter screw length

Compression ratio the screw

Extruder head nozzle screens

Cylinder section temperature

Temperature of the extruder head

Speed of the screw

25 mm 750 mm

3.0

8 mm in diameter and 100 mm in length

1 sieve with a mesh size of 0.175 mm and 1 sieve with a clear mesh size Mesh size of 0.147 mm

C ₁ = 60 to 120 ⁰ C \ = 100 to 160 ⁰ C

C ₃ = 120 to 180 ^° C

100 to 130 ⁰ C 50 min

-1

The density of the foam test pieces obtained is determined and checked the cell structure. The results are summarized in Table 7.

The abbreviations used in Table 7 for the physical and chemical blowing agents are the same as they are also used in the introductory examples.

The evaluation criteria A and B for the cell structure are the same as explained in Example 4. The evaluation criterion C for the cell structure means that the pores of the foam have a diameter of greater than 1 mm and the cell structure is inhomogeneous and coarse.

030021/0692

-yC- 29U068

The foam test specimen obtained after Experiment No. 87 proves to be remarkably brittle. The foam test specimens after experiments No. 91 and 92 show after Form a significant shrinkage.

030021/0692

29UQ68

Table 7-1

attempt No. density
(g / ml)
Cell structure
door 72 73 74 . ⁷⁵ 76 77 PVC Vinyl acetate
salary
(Wt%) 5 10 0 10 10 10 resin P. 400 750 750 1000 1000 1000 Vp (ml / gl 0.011 0.013 0.060 0.025 0.025 0.025 physical
Trebsorbent
(G TCFM
(150)
+
BU
(100) TCFM
(150)
+
BU
(100) TCFM
(150)
+
BU
(100) TCFM
(150)
+
BU
(100) TCFM
(150)
+
BU
(100) TCFM
(150)
+
BU
(100) Recorded driving
medium amount _(weight> _ _%) 11 .0 10.8 7.8 9.7 9.7 9.7 Nucleating agent (wt .-%) Valley
(1.0) Talc
(1.0) Talc
(1.0) Haku-
enka
(1.5) Orbs
(5) Valley
(0.5) Chemical blowing agents
(Wt%) None Celmic
133
(1.0) PTS
(0.03) AIBM
(0.5) SHC
(0.5) *
SHC
(2) Acrylic resin (part by weight) 10 10 10 10 10 OK Foam-
material-
molded part 0.065 0.045 0.060 0.054 0.052 0.053 A. A. A. A. A. A.

Sodium bicarbonate

030021/0692

-Xf-

Table 7-2

78 79 80 81 82 83 84 85 86 10 35 10 10 10 10 1C 10 10 1000 1700 850 850 850 850 850 850 850 0.025 0.029 0.015 0.015 0.015 0.015 0.015 0.015 0.015 TCFM
(150)
BU
(100) TCFM
(150)
+
BU
(100) PR
(300) BU
(300) PE
(300) TCFM
(300) TCFM
(300)
+
BU
(300) TCFM
(100)
+
BU
(100) TCFM
(200)
+
BU
(400) 9.7 9.3 6.5 7.5 8.3 15.6 3.4 8.6 15.0 Talc
(0.05) Talc
(1.0) Talc
(0.5) Talc
(0.5) Talc
(1.0) Talc
(1.0) Talc
(1.0) Talc
(1.0) Talc
(1.0) SHC *
(5) without without without Celmic
133
(2.0) Celmic
il% Celmic
133
(0.5) Celmic
133
(0.5) Celmic
133
(0.5) 10 10 10 10 5 5 5 5 5 0.046 0.068 0.080 0.071 0.085 0.058 0.090 0.069 0.045 A. A. A. A. A. A. A. A. A.

030021/0692

-IfCr

rc

Table 7-3

I 87 88 89 90 10 10 0 10 290 800 1700 2100 0.015 0.030 0.25 0.12 TCFM
(150)
+
BU
(200) TCFM
(150)
+
BU
(200) TCFM
(150)
+
BU
(200) TCFM
(150)
+
BU
(200) 9.0 7.3 2.7 3.5 Talc
(0.01) Talc
(1.0) without without without without AIBN
(1.0) Ol Il HJ 0 0 0 10 0.15 0.25 1 .1 1. i B. B. C. C.

030021/0632

Example 8 (experiments nos. 96-109)

A 100 1 stainless steel autoclave equipped with a stirrer is filled with 30 kg of a copolymer of 90% by weight vinyl chloride and 10% by weight vinyl acetate with an average degree of polymerization of 1050 and a pore volume of 0.023 ml / g, 50 kg of purified water , 15 g of a partially saponified polyvinyl alcohol and 6 kg of trichlorofluoromethane and a further 3 kg of butane were added under pressure. The mixture is then ^{heated to 70 °} C. for 8 h with stirring. The resin absorbs the mixture of trichloride fluoromethane and butane, which serves as a physical blowing agent. After the impregnation is complete, the mixture is cooled to room temperature and the excess propellant mixture is discharged from the reactor. The impregnated resin is then dehydrated in the centrifuge and ^{dried at 40 to 50 °} C. in a stream of warm air. The total trichlorofluoromethane and butane content of the resin impregnated in this way is 12.0% by weight.

Using the resin component impregnated with the physical blowing agent in this way, a foam is made -Mould made by mixing 100 parts by weight of the with the physical blowing agent impregnated resin, 2 parts by weight of a tin-containing stabilizer and 1 part by weight of calcium stearate and optionally additionally 1 part of talc as a nucleating agent, 0.5 part by weight of the commercially available one also used in Example 4 Azodicarboxamide ("Celmic 133") as a chemical Blowing agent and one of acrylic resins E-7 to E-13 in DE amount given in table 8. The foam molding compounds produced by mixing the components together become tabular foam specimens produced. The examinees are made on an extruder.

$ 30021/0602

The nucleating agent is not added in Run Nos. 106 and 107. No chemical blowing agent is in the experiments nos. 106 and 108 admixed.

The abbreviations "used in Table 8 for the Acrylic resins are defined as follows:

E-7: A copolymer comprising, the methacrylate of 90 wt .- 'i is methyl and ethyl acrylate and 10 weight -'4 a reduced viscosity of 4.5 dl / g at 25 ⁰ C..

E-8: A copolymer which consists of 90% by weight methyl methacrylate and 10% by weight ethyl acrylate and has a viscosity number of 7.0 dl / g at 25 ^° C.

E-9: A copolymer which consists of 90% by weight of methyl methacrylate and 10% by weight of ethyl acrylate and has a viscosity number of 11.0 dl / g at 25 ^° C.

E-10: A copolymer which consists of 90% by weight of methyl methacrylate and 10% by weight of ethyl acrylate and has a viscosity number of 15.3 dl / g at 25 ^° C.

E-I1: A copolymer which consists of 95% by weight of methyl methacrylate and 5% by weight of butyl acrylate and has a viscosity number of 10.7 dl / g at 25 ^° C.

E-12: A copolymer which consists of 80% by weight of methyl methacrylate, 5% by weight of ethyl acrylate, 5% by weight of butyl acrylate and 10% by weight of butyl methacrylate and has a viscosity number of 11.0 dl / g at 25 ⁰ C.

E-13: A comprises copolymer consisting of 80 wt .-% methyl methacrylate and 20 parts by weight ι, ethyl ordered and a reduced viscosity of 2.0 dl / g at 25 ⁰ C.

030021 / OG92

The specimens are extruded under the following conditions:

Screw diameter screw length

Compression ratio of the screw

Slot nozzle from the extrusion head screens

Temperature of the cylinder sections

Temperature of the extruder head
Speed of the screw

65 mm
1,950 mm

3.0

100 mm wide and 8 mm high 1 sieve with a mesh size of 0.175 now and 1 sieve with a mesh size of 0.14 7 mm

C, = 95 ^° C

C, = 130 ^° C
C ₃ = 150 ^° C

120 ⁰ C
20 min

On the foam test specimens produced in this way the effective density, the cell structure, the compressive strength (according to ASTM D 1621) and the flexural strength (according to the international standard ISO R 1209). The results are shown in Table 8.

In experiments nos. 104 and 105, foaming begins of the molding compound too early, even while the molding compound is in the extruder head. This leads to broken up Foam structures and strong shrinkage of the molded part. It also becomes a less uniform one Cell structure preserved. The foam moldings produced according to experiments nos. And 109 also have a less homogeneous cell structure, but no

030021/0692

ΪΗ

too early onset of the foaming process observed.

The results shown in Table 8 show that by using an acrylic resin with a higher viscosity number the The amount of acrylic resin to be used to achieve comparable results can be reduced, while at the same time the Retention of the propellant gas and the stabilization of the pores of the foam structure can be improved and the shrinkage can be reduced. On the other hand, if the viscosity number is too low or the viscosity is too low Amount used are largely broken up Preserved foam structures. In addition, there is a strong shrinkage of the foams after they have been molded and the formation is coarser Cell structures in the foam structure.

Table 8-1

Attempt no. density
(g / ml) 96 97 98 99 100 101 Acrylic resin
(^ ew.-parts) Cell structure
door E-7
(10) E-8
(6) E-9
(5) E-11
(6) E-12
(6) E-10
(2) Own
sheep
th
of
Foam-
material-
For in
te ll s Druckfestic
speed
iW / rri *) 0.048 0 _f 048 0.043 0.050 0.049 0 _; 067 Bieael "; jstiq
speed
(W / mm ² ) A. A. A. A. A. A. 3.4 3Λ 3.0 ^ 5 4.4 6.3 5.7 5.6 5.0 6.3 6.0 9> 3

030021/0692

29U068

Table 8-2

102 103 104 105 106 - 107 108 109 E-10
(5) E-10
(25) E-10
(0.3) E-13
(5) E-7
(10) - E-7
(10) without without 0.042 0.050 0.23 0.25 0.12 0.095 0.16 0.15 A. A. e β B. B. C. C. 3 _f 0 3.6 21.0 22.3 - - - 5.1 6.5 29.3 30.4 - - -

Example 9 (Experiment No. 110 to 117)

A 10 1 stainless steel autoclave equipped with a stirrer is filled with 3 kg of a polyvinyl homopolymer or a copolymer of vinyl chloride and vinyl acetate with the vinyl acetate proportions given in Table 9 and an average degree of polymerization and pore volume, which are also given in the table, 5 kg of purified water 1.5 g of a partially saponified polyvinyl alcohol and 600 g of trichlorofluoromethane and 300 g of butane are charged under pressure. Subsequently, 8 heated with stirring to 70 ⁰ C h, wherein the resin of the Trichlorf luormethan / butane mixture, which serves as a physical blowing agent receives. After the impregnation of the resin component is complete, it is cooled to room temperature and the excess blowing agent is discharged from the autoclave.

03002 1/0692

rf 29AA068

rs

The resin is then separated from the aqueous phase by filtration and ^{dried at 50 °} C. for 5 hours in a stream of warm air. The amounts of blowing agent absorbed by the resin are shown in the table for each individual test.

An expandable foam molding compound is produced, by mixing 100 parts by weight of the resin impregnated with the physical blowing agents, 2 parts by weight a tin-containing stabilizer, 1 part by weight calcium stearate, 1 part by weight of talc as a nucleating agent and 10 parts by weight of one of the acrylic resins E-7, E-10 or E-13 (see Example 8) as a pore regulator resin. The molding compositions thus produced become cylindrical in the manner described in Example 7 Extruded material and foamed. On these foam specimens the density and the cell structure are determined bzu. checked. The results obtained are summarized in table 9. The foam specimens obtained after Experiments 115 and 116 showed a slight shrinkage after molding.

The data compiled in Table 9 show that the higher the degree of polymerization of the PVC resin an acrylic resin with a correspondingly higher viscosity number should be used. Under these circumstances you can Foam molded parts with a large increase in volume can be obtained with a homogeneous cell structure even if the Pore regulator resin contains only a small amount of vinyl acetate. Otherwise, relatively high processing temperatures would be required can be set. These effects can be achieved in the manner shown in Table 9 or the undesired ones Avoid disadvantages that the acrylic resin, which is used as a pore regulator resin, in the illustrated Adaptation to dat> PVC resin is selected.

030021 / 0S92

Tabel

Attempt no. Vinylaceta
proportion of
(Gev .-%) • Density
(g / mr> 110 111 112 113 .. 114 115 116 117 resin P. Cell
structure 5 5 10 0 10 10 0 0 Vp, (ml / g ^ 700 1050 1500 850 510 1500 850 850 Acrylic resin
(Parts by weight) 0.021 0 _T 025 O _t O33 0 _t 038 0.019 0.033 0 _T 038 0.038 foam
material-
Shape-
part E-10
(10) E-10
(10) E-10
(10) E-10
(10) E-7
(10) E-7
(10) E-7
(10) E-13
(10) 0 _f 048 0.051 0.066 0.060 0.040 0.081 O ₁ 093 0 _r 25 A. A. A. A. A. A (* 1) A. B.

Example 10 (experiments No. 118 to 1339)

A 5 l stainless steel autoclave equipped with a stirrer is filled with 1000 g of a homopolymeric polyvinyl chloride or a copolymer of vinyl chloride and vinyl acetate with the vinyl acetate content indicated in Table 10 and an average degree of polymerization and pore volume, which are also indicated in Table 10, with 2000 g of purified water, 1.0 g of partially saponified polyvinyl alcohol and 150 g of trichlorofluoromethane and 100 g of butane are charged under pressure. The mixture is then ^{heated to 70 °} C. for 8 h with stirring. The resin component is saturated with the trichlorofluoromethane / butane mixture, which serves as a physical blowing agent. After completion of the impregnation, cooling to room temperature and discharging the excess blowing agent, the resin is filtered off and dried ^{in a stream of warm air for 5 hours at 40 to 50 ° C.}

The total amount of the blowing agent absorbed in the resin component is given in the table for each individual case. The loss of blowing agent after storage for 1 week at 20 ^° C. is of the order of 6 to 9% by weight for all impregnated resins.

Using the resin components produced, a molding compound is produced by mixing 100 parts by weight each of one of the PVC resin impregnated with the physical blowing agent, 2 parts by weight of a tin-containing stabilizer and 1 part by weight Part of calcium stearate, optionally with an additional nucleating agent of the type specified in Table 10 in the amount specified there, a chemical blowing agent, which is also specified in Table 10, and a copolymer resin S-1, which is 70% by weight consists of styrene and 30 wt .-% acrylonitrile and has a viscosity number of 12.0 dl / g at 25 ⁰ C and as foam regulator resin

030021/0692

29U068

is based on styrene. The amounts in which these styrene resin components are added are also given in Table 10. The molding compositions produced in this way are extruded into cylindrical strand material. The extruder also used in Example 7 is used and the extrusion conditions specified there are adhered to.

The cylindrical foam specimens thus obtained are examined with regard to their density and their cell structure.

The results obtained are summarized in Table 10.

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29A4068

ίο

Table 10-1

Trial No. Vinyl acetate
proportion of
(Wt %) density
(g / mr> 118 119 120 121 122 123 resin V Inch structure 5 10 0 10 10 10 Vp, ml / g 400 750 750 1000 1000 1000 au f ijonommener '!' ro ib-
mit t.tel ^ ntei 1
(Wt. -Ι.) 0 _f 0l 1 0.013 0.060 O _T O25 0.025 0.025 No-builder
(Parts by weight 1 1, 0 10.8 7.8 9 _r 7 9 ₇ 7 9.7 former propellant
(Parts by weight) Valley
(2.0) Valley
(1.0) Valley
(1.0) Valley
(0.03) Valley
(0.5) Orbs
(5) Styrene resin S-1
(Parts by weight) without Celmic
133
(1.0) without SHC
(4.0) Celmic
133
(1.5) AIBN
(0.5) Foam-
material-
Shape-
toil 6.0 6.0 10.0 8.0 8.0 8.0 0.060 0.044 0 _r 06i 0.049 0.050 0.055 A. A. A. A. A. A.

0 3 0021/0692

-xf-

(.4

Table 10-2

124 125 127 128 129 130 131 132 10 35! 10 10 10 0 10 . 45 1000 * 1700 1000 1000 1000 1700 2100 1800 0.025 0.029 0.030 0.030 0.030 0.25 0.21 0.025 9.7 9.3 9 _f 4 V 9.4 2.7 3.5 6.0 Haku-
enka
(20) Talc
(1.0) Talc
(1.0) without ohm. ( without Valley
(1.0) PTS
(0.3) without without' AIBN
(1.0) without without without without 8.0 1O ₇ O without- .without 8th without 8th ohni » 0.060 0.069 0.20 0 _r i8 0.20 V ¹ F ¹ 0.30 A. - A C. C. C. C. C. 8th

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Example 11 ( Trials No. 13 4 to 143)

One equipped with a stirrer 5 autoclave made of stainless steel is charged with 1000 g of a copolymer of 90 wt -.% Vinyl chloride and 10 wt .-% of vinyl acetate having an average degree of polymerization of 850 and a pore volume of 0.015 ml / g, 2000 g of purified water and 1.0 g of a partially saponified polyvinyl alcohol and one or a mixture of two different physical blowing agents under pressure. The blowing agents used in each case are listed in Table 11. After the autoclave has been charged, the mixture is ^{heated to 70 °} C. for 8 hours while stirring. The resin absorbs the propellant components.

After completion of the impregnation, cool down to room temperature and discharging the excess propellant from the autoclave, the resin is dehydrated by centrifugation and then dried in a stream of warm air. The ones absorbed by the PVC resin The amounts of propellant are listed in Table 11.

Expandable molding compounds are made from these impregnated resin components produced by mixing 100 parts by weight of each one in the manner described above manufactured and impregnated with the physical blowing agent Resin with talc as a nucleating agent, a commercially available acodicarboxamide (Celmic 133) as a chemical blowing agent and the styrene resin S-1 as foam control resin, the individual components in the amounts given in Table 11 can be used. The foamable molding composition produced in this way is used in the manner indicated in Example 10 Foam test specimens produced. On these test items determines the density. The results are summarized in Table 11. The foam moldings that are used in the Try nos. 1 '1 and 142 get werdi-n, zoiijen after Forming a noticeable shrinkage.

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Table 11

Attempt no. 134 135 136 137 138 Γ 39 140 141 142 143 ohvs. Propellant
(S) PR
(300) BU
(300) PE
(300) TCFM
(300) TCFM
(3 ₊ 0)
BU
(30) TCFM
dqp)
BU
(100) TCFM
(29O)
BU
(400) TCFE
(200) ISO
(8.4) TCFM
(30) recorded
Propellant quantity
(Wt%) 6.5 7.5 8.4 15.6 3.5 8.9 14.0 11.0 8.4 Tale (parts by weight 1.0 1.0 2.0 2.0 2.0 2.0 2.0 1.0 1.0 1.0 Celmic 133
(Parts by weight) 0 0 1.0 1.0 0.5 0 _f 5 0.5 0.5 0.5 0 Styrene resin
S-1
(Geν; .- parts) 5 5 5 5 5 5 5 0 0 · 0 density
(g / ml) 0.075 0.064 0.084 0.052 0.088 0.068 0.041 0.79 0.94 0 _; 77

Example 12 (Experiments No. 14 4 to 150)

A 100 1 AutnkLav made of stainless steel, equipped with a stirrer, is charged with 30 kg of a copolymer made from ') ü C, ew .-% vinyl chloride and 10 wt .-% vinyl acetate with an average degree of polymerization of 1050 and a pore volume of U ₁ 023 ml / g, 50 kg of purified water, 15 g of a partially saponified polyvinyl alcohol and 6 kg of trichlorofluoromethane and 3 kg of butane were added under pressure. The mixture is then ^{heated to 70 °} C. for 8 h with stirring. The resin component absorbs the trichlorofluoromethane / butane mixture, which serves as a physical blowing agent. After the impregnation of the resin component, cooling to room temperature and removal of the excess propellant from the autoclave, the resin is dewatered by centrifugation and then in a hot air stream. dried at 40 to 50 ^{° C.} The resin component impregnated in this way contains a total of 12.0% by weight of blowing agent.

Expandable molding compounds are made from these impregnated resins by mixing 100 parts by weight the PVC copolymer resin impregnated with the physical blowing agent in the manner described above, 2 parts by weight of a tin-containing stabilizer, 1 part by weight of calcium stearate, 1 part by weight of talc as a nucleating agent, 0.5 part by weight a commercially available azodicarboxamide (Celmic 133) as a chemical blowing agent and one of the styrene copolymer resins S-J to S-5 as a pore regulator resin. The amounts in which these components of the molding composition are incorporated are in the Table 12 shown. The styrene copolymer resins have the Eo1qende composition:

S-2: A copolymer of 70% by weight styrene and 30% by weight acrylonitrile with a viscosity number of 2.0 dl / g at 2 5 ^° C.

S-3: A copolymer of 70% by weight styrene and 30% by weight Acrylonitrile with a viscosity number of 4.0 gl / g

030021/0 69 2

Z 2 9 A 4 O B 8

at 25 ⁰ C.

S-4: A copolymer of 70 wt% styrene and 30 wt%

Acrylonitrile with a viscosity number of 10.0 dl / g at 25 ° C.

S-5: A copolymer of 75% by weight styrene and 25% by weight

Acrylonitrile with a viscosity number of 14.6 dl / ij at 25 ^° C.

The data compiled in Table 12 shows that styrene copolymer resins with larger viscosity numbers. When used as a pore retainer resin, an improved retention of the propellant gas or, what is equivalent, a cause improved structure of the foam structure, stabilize the foam and even then reduce shrinkage of the molded parts if only relatively small amounts of the styrene resin are mixed in. Using Styrene resins with values for the viscosity number that are too low are increasingly broken up and foams are reinforced Shrinkage of the molded part after molding and a coarser cell structure were observed.

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Table 12

Attempt no. density
fe / ml) 144 145 146 147 148 149 150 Styrene resin
(Parts by weight) Cell
structure S-3
(3.0) S-4
(2.0) S-4
(5.0) S-4
(25.0) S-5
(5.0) S-2
(5.0) S-4
(0.3) Own
societies
the
Foam-
material-
r'orm-
share
i pressure
strength
. (N / me. *) 0.045 0.059 0.044 O _; O53 0.042 0.16 C, 1 9 Flexural strength
ability (N / me / A. A. A. A. A. C. C. 0.2 9 c, 3 9 0.2 9 D ₁ 3 3 C, 2 6 22 4 28 4 [0.7 4 Ψ 3 0.7 3 0.8 6 0 ₍ 6 6 3.1 6 1.2 A

Example 13 (experiments No. 151 to 156)

A 10 1 stainless steel autoclave equipped with a stirrer is charged with 3 kg of a homopolymeric polyvinyl chloride or a copolymer of vinyl chloride and vinyl acetate with the vinyl acetate proportions given in Table 13 and the mean degree of polymerization and pore volume given in this table, 5 kg of purified water, 1, 5 g of a partially saponified polyvinyl alcohol and 600 g of trichlorofluoromethane and 200 g of butane are charged under pressure. The mixture is then ^{heated to 70 °} C. for 8 h with stirring. The resin component absorbs the mixture of trichlorofluoromethane and butane, which serves as a physical blowing agent. After completion of the impregnation, cooling to room temperature and discharging the excess blowing agent from the autoclave, the resin is separated from the aqueous phase by filtration and then dried ^{at 50 ° C. in a stream of warm air for 5 h.} The amount of blowing agent included in the resin component after this treatment is given in Table 13 for each individual case.

A foamable molding compound is made using the so produced impregnated resin components prepared by mixing 100 parts by weight of the with the blowing agents impregnated resin, 2 parts by weight of a tin-containing stabilizer, 1 part by weight of calcium stearate, 1 part by weight Talc as a nucleating agent, 0.5 part by weight of a commercially available azodicarboxamide (Calmic 133) as the chemical Propellant and a styrene resin of the type and amount shown in Table 13. The molding compound thus obtained becomes the foam moldings serving as test specimens in the extruded manner described in Example 10. The density and cell structure are examined on these test objects. The results obtained are also shown in the table. The test specimen obtained after test 155 shows

030021/0692

after molding, there is a slight shrinkage. The foam obtained after experiment 156 shows a break in the foam structure to a considerable extent. In the case of this specimen, this leads to severe shrinkage of the molded part after Molding.

The data compiled in Table 13 show that the viscosity number of the resin used as the pore control resin of the molding compound incorporated styrene resin should be greater, the greater the degree of polymerization of the PVC resin. Here can even then a foam molded part with a high degree of foaming and homogeneous cell structure can be obtained when as PVC resin a resin based on vinyl chloride with only very small amounts of vinyl acetate is used. Under these circumstances would otherwise be relatively high processing temperatures and careful selection of pore regulators is required.

On the other hand, even with a copolymer resin having a relatively low degree of polymerization, a highly foamed Foam body made with the addition of a polystyrene resin as Pore control resin can be obtained if this styrene pore control resin has a relatively low viscosity number. The prerequisite for this, however, is that the PVC resin component contains a slightly larger proportion of vinyl acetate. Highly foamed molded foam parts are under these conditions only with difficulty to obtain if the PVC copolymer oinon only <| i .. 'r i rujen Viny lace t-.a tan part.

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29U068

Table 13

Attempt no. density
(g / ml) 151 152 153 154 155 156 PVC
resin
1 Cell structure 5 10 0 10 10 0 Vinyl acetate
proportion of
(Wt%) 700 1500 750 800 1500 850 P " 0.021 0.033 0.037 0.021 0.033 0.038 / ρ (ml / g) 11.5 10.5 10.1 11.5 10.5 10.0 recorded
Amount of propellant
(Wt%) S-5
(6) S-5
(10) S-5
(10) S-3
(10) S-3
(10) S-2
(10) Styrene resin (part by weight)
Ie) 0.043 0.059 0.055 0.050 0.073 θ ", 15 Foam-
material-
Shape-
part A. A. A. A. A. C.

03 0021/0692

Claims (14)

Invention claim: 1. Molding compound containing blowing agent with a synthetic resin based on polyvinyl chloride for the production of molded foam parts with heating,
marked by (a) 100 parts by weight of a synthetic resin based on polyvinyl chloride with an average degree of polymerization of not larger than 2000 and a pore volume of not greater than 0.20 ml / g and (b) at least 1 part by weight of an aliphatic hydrocarbon and / or a halogenated aliphatic hydrocarbon with a boiling point of not greater than 90 ^° C. as a physical blowing agent with which the synthetic resin based on polyvinyl chloride is impregnated. 2. Molding composition according to claim 1, characterized by the following additional components: (c) 0.5 to 30 parts by weight of an acrylic resin or a styrene-based resin as a pore control agent and (d) 0.01 to 20 parts by weight of a nucleating agent. 030021/0002 ~ ² ~ 294A068 3. Molding composition according to one of claims 1 or 2, characterized in that that the synthetic resin based on polyvinyl chloride is a copolymer composed of 60 to 97% of vinyl chloride units and to 40 to 3 wt .-% consists of vinyl acetate units. 4. Molding compound according to one of claims 1 or 2, characterized in that that the synthetic resin based on polyvinyl chloride has an average degree of polymerization of at least 300. 5. Molding compound according to claim 2, characterized , that the resin used as a pore regulator has a viscosity number of at least 3.0 dl / g, measured in chloroform at a concentration of 0.1 g / 100 ml and 25 ^° C. 6. Molding compound according to claim 2, characterized , that the nucleating agent is a powdery inorganic substance is, which has an average particle diameter of not greater than 30 μm. 7. Molding compound according to claim 2, characterized , that the nucleating agent is a combination of one at room temperature solid acid and a carbonate or hydrogen carbonate of the cations sodium, potassium or ammonium isu. 8. Molding compound according to claim 7, characterized , that the acid that is solid at room temperature is boric acid or a solid organic acid, namely citric acid, tartaric acid or oxalic acid. 030021 9. Molding composition according to claim 2, characterized in that the acrylic resin is oil in polymethyl methacrylate. 10. Molding compound according to claim 2, characterized , that the acrylic resin is a copolymer of methylniethacrylate and is at least one of the following acrylic acid esters: an alkyl acrylate and / or an alkyl methacrylate, as long as this is not methyl methacrylate. 11. Molding compound according to claim 10, characterized in that the methyl methacrylate content in the copolymer is up to 95% by weight. 12. Molding compound according to claim 2, characterized , that the styrene-based synthetic resin is a copolymer composed of 90 to 40% by weight of styrene and 10 to 60% by weight % By weight of a comonomer copolymerizable with styrene consists. 13. Molding compound according to claim 12, characterized , that the comonomer copolymerizable with styrene is acrylonitrile. 14. Molding compound according to one of claims 1 or 2, characterized in that that these in addition in an amount of not great contains as 5 parts by weight of a chemical blowing agent, based on 100 parts by weight of the physical Propellant impregnated synthetic resin based on polyvinyl chloride.