DE1947924C3 - Vinyl chloride polymers and process for their preparation - Google Patents

Description

45

Vinyl chloride homopolymers and their copolymers with other ethylenically unsaturated monomers have long been known and are currently used in a wide range of applications by the plastics industry. You can search for different Process described in detail in numerous patent specifications and technical publications are to be produced. These processes are generally carried out as bulk or bulk polymerization a monomer or a monomer mixture or as a solution, emulsion or suspension polymerization in an aqueous medium designated. In all of the processes, the polymerization occurs primarily through the bringing together of the monomer or the monomer mixture with suitable polymerization catalysts which generate free radicals accelerated. However, since higher polymer yields are generally more economical and convenient can be achieved by the emulsion or suspension process in an aqueous medium in practice for the production of vinyl chloride polymers mainly these types of proceedings are preferred.

In the aqueous suspension polymerization processes used hitherto, the vinyl chloride monomer or a mixture with one or more other copolymerizable monomers is brought into contact with a polymerization catalyst which generates free radicals, a suspension which is stable in an aqueous medium being maintained by means of a suspending or dispersing agent. The reaction mixture ", which usually fills the reactor up to 80% by volume, is then kept under an established pressure and at various temperatures for various periods of time. The various periods of time depend, for example, on the particular catalyst used and the desired average molecular weight next applying reaction temperature is usually between 20 ° and 100 ° C, preferably between 20 and 8O ⁰ C, the reaction time is up to 24 hours or even longer.

More recently, the vinyl chloride graft copolymers are known. These products usually have properties that are somewhat different from the Differentiate vinyl chloride homopolymers or their statistical copolymers. Graft copolymers are mainly made by reacting a polymer in an aqueous suspension with vinyl chloride or a mixture of this compound with another monoethylenically unsaturated compound Monomers produced. Usually this reaction takes place in the presence of a free radical generating connection carried out.

This method is described in numerous patents such as U.S. Patents 3,305,606 and 3,332,858 and British patents 1,021,324, 1,075,642 and 1,075,643. the The catalysts used in this process are the same as those previously known for their manufacture Vinyl chloride homo- and copolymers were used. In the same way are the conditions for Perform the graft polymerization essentially the same as for the preparation of the others Polymers, i.e. the graft polymerization is generally carried out at temperatures between 20 and 100 ° C, preferably between 20 and 80 ° C, for a period of around 20 or more hours carried out.

The invention now relates to branched, thermoplastic vinyl chloride polymers with CH3 and 3 to 14 CH ₂ Cl end groups on the branches per 1000 CH ₂ groups and a content of at least 50 percent by weight vinyl chloride units, obtained by suspension polymerization of vinyl chloride, a mixture of vinyl chloride and a comonomer or a mixture of vinyl chloride and a solid polymer graftable with this in the aqueous phase in the presence of monomer-soluble, free radical-forming catalysts at temperatures of 90 to 165 ° C and under increased pressure, which are characterized in that they are polymerized during the total reaction time maintained hydrostatic pressures of 28 to 350 kg / cm ^{2 were} obtained.

The invention also relates to a process for the production of vinyl chloride polymers, which contain at least 50 percent by weight of vinyl chloride units, by suspension polymerization of vinyl chloride, a mixture of vinyl chloride

and a comonomer or a mixture of vinyl chloride and a solid polymer graftable with this in the presence of monomer-soluble, free radical-forming catalysts in the aqueous phase at temperatures of 90 to 165 ° C and under increased pressure, which is characterized in that the polymerization during de . total reaction time at hydrostatic pressures of 28 to 350 kg / cm ² .

The polymers according to the invention are distinguished by a special structure, an unexpectedly high one Heat resistance and good processing properties.

It is already known. Polymerize vinyl chloride in aqueous suspension in the presence of catalysts which form free radicals at temperatures within the range from 90 to 165 ° C. and high pressures for times within the range from 1 to 12 hours (cf. Journal of Polyir> er Science Vol. XLI [1959 ], Pp. 73-82, especially p. 74, table I, experiments 1 and 2 and the last two lines before the table). In these known processes, however, if the autoclave is charged with the filling quantities customary in vinyl chloride suspension polymerization and the autogenous pressure is consequently established, a pressure within the range from 28 to 350 kg / cm ^{2 is} not maintained during the entire reaction time. In this way, polymers are obtained which are inferior in terms of heat resistance to those obtained according to the invention, such as those shown in Comparative Experiments A and B below and also FIGS. 1 and 2.

The polymers produced according to the invention can be used for many different plastic applications can be used. The vinyl chloride homopolymers can be used, for example, as adhesives, as flame retardants and used as processing aids in the manufacture of other polymers. You can also as a plastic component in vinyl flooring material as well as in the production of solid vinyl foam.

StaiiiUschen copolymers are currently found as a process modifier and as a plastic component in vinyl flooring material and in vinyl records use. The graft polymers are particularly valuable for the production of Coatings and for various articles made by compression molding or injection molding.

The terms "vinyl polymers" and "vinyl chloride polymers" used here and below refer to vinyl chloride homopolymers and random copolymers with one or more other monoethylenically unsaturated compounds. Particular cornonomers which are suitable for use are olefins having 2 to 4 carbon atoms, i. Ethylene, propylene or butene-1, monoolefinically unsaturated Carboxylic acids with 3 to 4 carbon atoms, such as acrylic or methacrylic acid, lower alkyl esters Acrylic and methacrylic acid and their hydroxy- and amino-substituted derivatives, vinyl esters of unbranched or branched monocarboxylic acids with 2 to 12 carbon atoms, maleic anhydride and the diesters of maleic and fumaric acid with aliphatic alcohols that contain up to 18 carbon atoms. Likewise can according to the process of the invention, random copolymers of vinyl chloride with styrene or its suitable ones Derivatives, e.g. p-chlorostyrene or p-tert.-butylstyrene, can be obtained. The producibility of these special copolymers is completely unexpected, in view of the fact that it has not previously been easy to polymerize these polymers by aqueous suspension to divide what the enormous difference between the responsiveness of the is attributable to both monomers in the Polymerisatjonssystem.

In general, the random copolymers according to the invention contain 50 to 99.5 percent by weight, preferably about 65 to 99 percent polymerized vinyl chloride and 0.5 to 50 percent by weight Percent by weight, preferably 1 to 35 percent by weight of the polymerized comonomer. The for Currently preferred polymers are those which contain vinyl chloride, which with olefins, in particular is copolymerized with propylene, since these products are best suited to a wide range of applications can be.

The terms "vinyl polymers" and "vinyl chloride polymer" are also intended to refer to copolymers which contain polymerized vinyl chloride that is grafted onto another polymer, which can be a homopolymer or a copolymer. Currently preferred polymers for grafting according to the process of the invention are, for example, polyolefins, such as polyethylene or polypropylene, their chlorinated derivatives and copolymers of the olefins mentioned. Homopolymers of Vinylester of monocarboxylic acids having 1 to 8 carbon atoms, for example vinyl acetate, vinyl propionate or vinyl butyrate, and copolymers thereof with C _{2 4} olefins, said copolymers containing a varying weight percent of polymerized Vinylester. Homopolymers of acrylic and methacrylic acids and their lower alkyl esters, homopolymers of acrylamide, methacrylamide and acrylonitrile and the copolymers of these monomers.

The grafted copolymers according to the invention generally contain 60 to 95 percent by weight of polymerized vinyl chloride, the total weight of the polymer being 5 to 40 percent by weight Polymer substrate are included. The currently preferred graft polymers contain 75 to 85 percent by weight of polymerized vinyl chloride and 15 to 25 percent by weight of ethylene-vinyl acetate copolymer. The copolymer in turn contains 10 to 40 percent by weight, preferably 18 to 30 percent by weight, polymerized vinyl acetate.

Both the products according to the invention and representative examples of known vinyl chloride polymers with different average _{molecular weights were examined for methyl end groups (CH 3} ) with the aid of infrared spectroscopy (IR). These samples were examined before and after they were reduced by the known standard method of hydrogenation with lithium aluminum hydride (LiAlH _4). Details of the investigation methods carried out are given later in a specific example.

The investigations on the tacticity of the molecule by IR revealed that conventional polyvinyl chloride (prepared at below 90 ⁰ C) somewhat more syndiot? Ktisch is constructed as the polymers of this invention. The test results also show that in the branches of conventional polyvinyl chloride the CH, end groups adjacent to the monomer units are predominantly head-to-head.

Have configuration. This can be seen from the fact that almost the same values for the number of CH ₃ groups per 1000 CH ₂ groups are found for both polymers before and after the reduction. As already stated, conventional vinyl chlorine polymers are those which are obtained at polymerization ^{temperatures of from 0 to 90 °} C., preferably from 20 to 80 ^° C. The average content of CH _{3 end} groups in these non-reduced polymers is about 9 to 10 CH ₃ groups per 1000 CHj groups. The analysis of the polymers after the reduction gives values of about 10 to 13 C Hj-Gnippen per 1000 CH ₂ groups. If chlorine is replaced by hydrogen during the reduction, it must be ensured that the fixed ^CT difference of CH ₃ groups of the unreduced polymer compared to that of the reduced polymer, ie 1 to 3 CH ₃ groups per 1000 CH ₂ - Groups to which chloromethyl groups at the ends of the branching chains of the unreduced polymer can be assigned. During the reduction of the polymer, the C'H ₂ -Cl end groups are converted _{into CH 3 groups.} On the basis of the analysis it is therefore concluded that conventional vinyl chloride polymers contain _{on average about 10 CH 3} groups and a maximum of 3 CH ₂ C1 groups for every 1000 CH _{2 groups.}

It has been found that the vinyl chloride polymers according to the invention have almost no tacticity, ie these polymers have almost the same percentage of syndiotactic and isotactic components. In these polymers, the branching increases with the same order of magnitude with which the polymerization temperature to be used is increased from 90 to 165.degree. According to analysis, for _{every 1000 CH 2} groups, these polymers contain 10 to 13 CH _{3 end} groups on the branches; the highest CH ₃ group value was detected in a polymer which was produced at the highest polymerization temperature. The same analysis of the reduced polymer gives values of 13 to 27 CH _{3 end} groups per 1000 CFi ₂ groups. The increase in the content of CH ₃ groups in the polymers of the invention is accordingly between 3 and 14 CH ₃ groups to 1000 CH ₂ groups after the reduction. When comparing the number of end groups to be found in the conventional vinyl chloride polymers, the increase mentioned is _{attributable to the larger number of CH 2} C1 end groups on the side chains. In contrast to the conventional polymers, the vinyl chloride polymers of the invention contain on average 3 to 14 CH ₂ C1 end groups per 1000 CHi groups.

It was found that melting point measurements on the reduced polymers showed no degradation indicate, i.e. no cleavage of the chain was caused in the course of the reduction.

Further analyzes showed that a polymer of the invention had a higher average molecular weight than some other conventional vinyl chloride polymers but it still has a lower intrinsic viscosity than conventional vinyl chloride polymers Has. which is due to higher branching.

In order to produce a vinyl chloride homopolymer or a random copolymer according to the process of the invention, it is placed in a suitable container which contains a suspension aid dissolved in an aqueous medium. Introduced vinyl chloride or a mixture thereof with one or more monomers copolymerizable with this. Thereafter, the monomer in aqueous suspension is heated with stirring to 90 to 165 ° C, whereupon enough water is pumped into the reaction vessel to achieve a pressure which is at least equal to the reaction conditions used, but preferably above the vapor pressure of the given polymerisation temperature is the monomer or monomers used. While stirring the Monomerensuspension fo ^r '.geset / t is, the free radical generating catalyst is added all at once to the reaction vessel, or it is required as an alternative

per menu and catalyst running during the reaction added The particular way of adding the catalyst is both of the particular catalyst also dependent on other factors described in more detail later. During the reaction, additional necessary water is pumped into the reaction vessel in order to maintain such a pressure therein which is at least equal to or above the vapor pressure of that which has not yet reacted in the reaction mixture Monomer or the monomer mixture, must be.

To graft polymerization products according to the invention to produce, the process is carried out essentially as described; however, before the Addition of the vinyl chloride monomer, the polymer to be grafted into the reaction vessel and placed in dispersed in the aqueous medium. In addition, before the addition of the catalyst, after the ongoing Adding the monomer, heating the reaction mixture to the desired polymerization temperature and after a sufficient reaction pressure has been reached, the reaction mixture, preferably during a period of e.g. B. 15 to 30 minutes, stirred. In this way the suspended swells Polymer and is finally partially dissolved by the monomer, which causes the grafting effect is enlarged.

The process according to the invention can be carried out in any suitable reaction vessel which is provided with a stirrer and which is made of corrosion-resistant material. z. B. made of stainless steel. The reaction vessel must be designed so that it can withstand pressures which are at least equal to, if not greater than, the vapor pressure of the monomer or the monomer mixture at the polymerization temperatures. Stainless steel reactors that can withstand 35 to 350 kg / cm ² are particularly useful and effective as polymerization kettles.

As already pointed out above, the process is generally carried out at a pressure of at least the vapor pressure of the vinyl chloride monomer or mixture of monomers at the particular polymerization temperature is the same, performed. The required pressure in the container is generated by pumping in a sufficient amount of water

posed. In the presently practiced, preferred practice of the invention, the reaction vessel is after the polymerization temperature has been reached and before a catalyst is added, im essentially filled with liquid. Accordingly, the pressure in the container is then substantially above that Vapor pressure of the monomer. This embodiment is used with preference because of conventional arrangements polymers degraded by heat on the

Walls of the reaction vessel above the surface of the liquid due to the extremely high polymerisation temperatures used. However, if one proceeds in such a way that the local catalyst concentrations do not develop too high, e.g. by inserting the catalyst under the surface of the reaction mixture, the Reaction vessel to avoid the formation of products that are not thermally degraded not to be almost completely filled with liquid. In a similar way - as stated above - the The total amount of catalyst required is introduced into the reaction mixture at the start of the reaction will. However, the required amount of catalyst can also be used as the reaction proceeds after> 5 and after being added At present, the continuous addition of the catalyst is preferred because this technique to control both the reaction rate and the indirect reaction temperature serves. The temptation to add the catalyst continuously or in portions allows the use of many catalysts which are extremely unstable at the polymerization temperature used are. If these are initially added completely to the reaction mixture, these catalysts would decompose very quickly and for the onset of the polymerization reaction will be ineffective. They could also pose a threat to the extent that that they can tend to explode. Of course, the polymerization catalyst can already be used at the beginning Reaction mixture can be given provided that the catalyst is not too unstable at the polymerization temperature is. It is said to have a half-life that is sufficient to eliminate free radicals for a period of time long enough to maintain the polymerization reaction to to produce their essential conclusion.

Any of the currently available monomer soluble free radical generating catalysts that have hitherto normally been beneficial for polymerization were used, e.g. B. for vinyl chloride in aqueous suspension, provided that it has a suitable Have decomposition rate at the polymerization temperatures and are reasonably stable on storage and are in use can be used as suitable catalysts. In selecting of the catalysts, their half-life at the polymerization temperature is of primary importance. These should be such that the catalyst is distributed throughout the reaction mixture prior to its decomposition can be. On the other hand, the half-life should be short enough that the catalyst during the polymerization is essentially completely decomposed and none of it remains in the final polymer. Dependent on of the polymerization temperatures used in particular Specifically suitable catalysts are the 2,4-dichlorobenzoyl, caprylyl, and the lauroyl peroxide, the tert-butyl peroxyisobutyrate, tert-butyl peroxypivalate, benzoyl peroxide, p-benzoyl peroxide, Hydroxyheptyl peroxide, cyclohexanone peroxide, di-tert-butyl diperphthalate, tert-butyl peracetate, tert-butyl perbenzoate, dicumyl peroxide, tert-butyl hydroperoxide, Methyl ethyl ketoperoxide, di-tert-butyl peroxide, acetylcyclohexanesulphonyl peroxide, di- (sec-butyl) peroxydicarbonate and isobutyryl peroxide. Of these compounds are preferred for the practice of the invention, according to which the catalyst is introduced in portions, those especially suitable which have a half-life within the polymerization temperature range from 0.1 second to 12 minutes, preferably from 0.5 to 5 minutes. Such currently preferred catalysts are e.g. benzoyl peroxide, tert-butyl peroxypivalate, Lauroyl peroxide, 2,4-dichlorobenzoyl peroxide, caprylyl peroxide, tert-butyl peracetate and p-chlorobenzoyl peroxide. In general, the concentration of the catalyst used is from 0.01 to 2.0%, based on the total charge of monomers. The preferred concentration is 0.05 to 0.5 Percentage by weight, calculated on the monomer.

Apart from the extremely high polymerization temperature, the process is generally similar to the well-known suspension polymerization conducted. For any proportion of vinyl chloride monomers or mixture of monomers 0.4 to 6 parts of water are required. The ratio of water to monomer is at 0.5 to 2: 1.

In order to maintain a stable suspension of the monomer in the aqueous medium, any of the currently available dispersing agents or the ScVnif ^ lcolloids, which are usually used in the system for vinyl chloride suspension polymerization serve, are used. The prerequisite for this is that these agents are both stable and completely soluble in the The polymerization temperature. Suitable suspension aids are currently e.g. B. polyvinyl alcohol, Carboxymethyl cellulose, polyvinylpyrrolidone and copolymers thereof, as well as the nonionics Alkylene oxide-alkylene glycol adducts. The concentration of the suspending aid is generally in the range between 0.05 and 4 percent by weight, based on the monomer or on the monomer mixture. The concentration of the suspension aid is preferably between 0.1 and 2 percent by weight, based on the monomer or on the monomer mixture, 0.2 to 1.0 percent by weight are more preferred.

The process according to the invention is, as already said, in a temperature range from 90 to 165 ° C carried out. As is to be expected, those produced at the upper limit of this temperature range have Polymers have a lower average molecular weight and are more branched than those Polymers that are produced at lower temperatures. Measurements due to the reduced Viscosity are used throughout to average comparative molecular weights of the products to obtain. The intrinsic viscosity numbers and the average molecular weights of the products in comparison with the conventionally prepared polymers, conclusions can be drawn about the degree of Branch to. Methods to determine these values will be described later.

The process according to the invention is generally carried out within 1 to 12 hours in front of him and depends on the specific temperature used, the specific catalyst and its Concentration. The total reaction time, i.e. the rate of polymerization, is also lost depends on the extent to which the heat of reaction is removed from the polymerization mixture. at current practice is to effectively remove the heat of reaction through use double-walled reaction vessel or, more advantageously, by a cooling coil, which is located in the reaction material is located. With the currently preferred

Embodiments of the method are carried out using such a cooling coil and in portions Addition of the catalyst during the course of the reaction from 90 to 95% of the monomer reacted over a period of 1 to 3 hours. Accordingly, the method of the invention provides an extremely economical method for the production of vinyl chloride polymers.

The average particle size of the vinyl chloride polymers of the invention can be between 50 and 400 μ. These products are different depending on theirs Structure valuable, e.g. B. as a flame retardant, as a processing aid for other polymers, such as plastic components in polyvinyl foam and flooring material, in the manufacture of various molded articles and of various coating compositions by calendering or roller coating.

For the preparation of liquid coating compounds for the production of coatings on various substrates however, polymers of significantly smaller particle size are required. Accordingly, will the method according to the invention when the vinyl chloride polymers should be used as a dispersion, latex or when using coating material in dissolved form in order to reduce the fine particle size of the polymer carried out with modifications. This is done, for example, by a small amount a Fm vision or wetting agent successively or at the same time with the suspending agent the polymenadion approach added to the desired reduction in the average particle size of the polymer to reach.

The reduced viscosity values for the polymers according to the invention are used to measure the molecular weights. These values are determined by preparing a solution of 1 g of polymer in 100 ml of cyclohexanone and measuring at 30 ^° C.: the flow time of this solution is compared with that of the cyclohexane using a calibrated pipette. The reduced viscosity is then calculated as follows:

7 ^, = solvent drain in seconds,

T ₁ = outflow of the dissolved polymer in seconds,

Specific viscosity = ~ - L

Red. Viscosity =

Specific viscosity
Γ

C is the concentration of the polymer in g / polymer per 100 ml of solvent.

According to the specific polymerization temperature used in each case and the catalyst used in each case, the vinyl chloride polymers have a reduced viscosity ranging from 0.12 to 0.58. It must be noted that in cases where a Homopolymer with an extremely low average molecular weight is desired, a chain terminator can be added to the reaction mixture can. In this way, polymers with a reduced viscosity value as low as 0.08 can be obtained. Suitable chain transfer agents are the lower aliphatic alcohols, such as isopropanol, and halogenated, e.g. B. chlorinated or brominated hydrocarbons with 1 to 6 carbon atoms.

The examples illustrate the invention. Marking parts focus on the weight.

example 1

Production of the vinyl chloride polymer

A 3.8 1 stainless steel reaction vessel, which can ^{withstand a pressure of 350 kg / cm 2} , is equipped with a mechanical stirrer, a cooling coil, a thermocouple, a pressure gauge with inlet for charging, a safety valve which is connected to a vent line , a. , armed. 1.5 l of fully demineralized, degassed water containing 7.2 g of dissolved polyvinyl alcohol are added to this reaction vessel. The reaction vessel is then closed and the oxygen is removed by pumping out several times to a pressure of 10 torr, whereupon the vacuum is replaced by introducing vinyl chloride. The reaction vessel is then charged with 908 g of distilled vinyl chloride with stirring, whereupon the reaction mixture is heated to 90 ° C. After that, will

In order to achieve a pressure of about ^{½ kg / cm 2,} a sufficient amount of fully degassed, degassed water in the reaction vessel. pumped. At this pressure the reaction vessel is almost completely filled with liquid.

While stirring is continued, 5 ml of a solution of tert-butyl peroxypivalate in trichlorotrifluoroethane (40 g of catalyst with 75% activity in 200 ml of solvent) are pumped into the reaction vessel. The polymerization is allowed to run without further addition of catalyst until a conversion of at least 30 "(approx. 15 minutes reaction time) has been reached Water is additionally pumped in to ensure that the reaction vessel is essentially filled with liquid. The total concentration of the catalyst is 0.37 percent by weight, based on the monomer. After the addition of the catalyst has been stopped, the reaction mixture is at 100 for 15 minutes ° C. The total reaction time is about 75 minutes.
The contents of the reaction vessel are then cooled, removed and the polymer spun off. It is washed repeatedly with deionized water and then dried under reduced pressure to a moisture content of less than 0.1 percent by weight. This polymer, which is obtained at 95% of the theoretical yield, has a reduced viscosity of 0.40.

Use of the polymer
as a flame retardant additive

To test the effectiveness as a flame-retardant additive, a portion of the polymer is according to Example 1 with commercially available, different low-pressure polyethylenes and with one Mixed polypropylene. In each experiment, 30 parts by weight, based on the total mixture, mixed into the polyolefin by means of a heated 2-roll mill. After 5 minutes of rolling the

The mixture is peeled off the stool as fur. Rolled heads of polyolefin are used as a control material manufactured. Samples are cut from the skins and checked for flammability after ASTM test standard D-635-63 tested. The following results were obtained:

Tabel

Polymer VValztempcrulur
(C) Dam area Burn rate Polyethylene D = 0.921,
Melt index 3.0
Polyethylene D = (1.921,
Melt-Im '- i.ü · PVC ...
Polyethylene D ₂ = 0.96 ^.
Melt index 6.0
Polyethylene D ₁ = 0.962.
Melt index 6.0+ PVC
Polypropylene D - 0.QOv
Sclimclz index \ 0
Polypropylene D = 0.905,
Melt index 5.0+ PVC 138
ns
168
168
177
177 burns
self-extinguishing
burns
self-extinguishing
burns
self-extinguishing lü, S cm / minute
15.2 cm / minute
19.5 cm / minute

Those samples containing the vinyl chloride polymer and non-drip, burn or smolder for 1.5 minutes be ^v or they scaling.

Determination of the physical properties of pressed samples of any of the foregoing Polymers and polymer mixtures prove that the admixture of the vinyl chloride polymer according to example 1 a significant increase in the strength of the polyolefins is achieved, what when comparing the higher tensile strength moduli for the samples from the polymer mixture compared to those of the straight-chain polyolefins apparently vwrd.

Comparative experiment A

This experiment shows that a thermally degraded vinyl chloride polymer is formed if the reaction vessel is not essentially filled with liquid while the process according to the invention is being carried out , given. The apparatus is closed and degassed as in Example 1, then 613 g of the purified vinyl chloride monomer are added under pressure. The reaction mixture is then heated to 100 ⁰ C. While stirring is continued, the pressure in the system is about 28 kg / cm ² . 4 ml of the 20% strength tert-butyl peroxypivalate solution with trichlorotrifluoroethane as solvent (cf. Example 1) are pumped into the reaction vessel, and the resulting mixture is further stirred for about 15 minutes. Thereafter, a total of 44 ml of the catalyst solution are added in portions of 2 ml each after every 5th minute. The pressure in the reaction area. container sinks to 7 kg / cm ² . The total reaction time is a little more than 2 hours. The reaction vessel is then cooled and the polymer is deposited, washed and dried as described in Example 1. The yield is about 85 % of theory. The polymer has a reduced viscosity of 0.39. In contrast to the product of Example 1, however, this polymer is partly decomposed, as can be seen from the dark particles which are contained in a considerable percentage.

Examples 2 and 3

In these examples, vinyl chloride homopolymers are used at 130 and 160 ° C according to the method described in Example 1 using the same Apparatus manufactured. In each experiment, the addition of the total amount of catalyst required continuously pumped in during the reaction and deionized water as needed to maintain it of the working pressure is also pumped in. The polymerization instructions and the reaction conditions are as follows:

Example 2 Example 3 Polymerization temp., ⁰ C ... 130 160 Working pressure, kg / cm ² 42 84 Total reaction time, Minutes 45 90 Fully demineralized water, ml ... 1000 1000 Aqueous suspending aid medium solution, g (2% Polyvinyl alcohol i. Water) 360 342 Vinyl chloride g 908 913 Total concentration of Catalyst, "" 1.0 1.9 Yield, \ the theory. .. 95 72.5 Reduced viscosity of the Polymer 0.25 0.14

Example 4

Polymerization products of Examples 1, 2 and 3 and selected samples of conventionally produced polyvinyl chloride are _{analyzed for the content of CH 3} groups, which are located at the ends of the branches, by means of a specially developed IR method. To compensate for the interference of the CH ₂ absorption bands for the amorphous part, soft usually in the range from 1380 cm 'to 1350 cm " ¹ in the Sneictren des

Polyvinyl chloride, a linear high density polyethylene used. This eliminates this area, which is analogous to that of polyethylene, and a sharp, symmetrical band of the CH ₃ group can be observed in the vicinity of the area of 380 cm '. The procedure is as follows:

Made of high density polyethylene, according to the M.C. Harvey and L.L. Peters, Anal. Chemistry, Vol. 32, No. 12, 1960, p. 1725, reported the method of making a wedge. The wedge is pointed and has a different thickness from 0.076 to 0.46 mm. It is cut up to make a 31.7x82.5 sample which is then placed on the metal frame of the Barnes variable path cell (the salt block removed). The frame is attached to the cell holder on a Teflon slider. the The sample is rotatably mounted to change the thickness.

In order to be able to analyze each polymer, a film is produced by pouring a solution of the polymer in tetrahydrofuran (0.25 g of polymer in 5 ml of solvent) onto a KBr plate. The solvent is in a furnace in which a reduced pressure prevails, for 30 minutes at 8O ⁰ C verdünstet. The dried film is examined for residual solvent by testing in the IR d>: r 5.5 μ to 6.0 μ and 9.2 to 9.5 μ areas. The completely dried film is then mounted on the holder.

The spectra of the polyethylene and polyvinyl chloride are recorded on a Perkin-Elmer model 521 infrared grating spectrophotometer. The slit diaphragm is at 332 μ; the gain factor is 4. The recorder is ^{manually set to 90 "" transmittance until 1600 cm l} . The sample film is placed in the beam path for samples and the polyethylene wedge is placed in the reference beam path. The wedge is rotated until the recorder opens 90 ° _o permeability is. the program speed is 50 cm '/ min., wherein the interference zero order is suppressed. When the two wings of the 1380 cm ^"1 band are non-uniform, they are compensated for by one cm, the recording drum to 1369' ¹ turn back and adjust the polyethylene wedge until the two wings of the 1380 cm 'gang are even. Then the drum is turned back to 1600 cm " ¹ and - if necessary - the adjustment button of the spectrophotometer is set so that the recorder is at 90 ° _o permeability. The range from 1600 to 1100 cm" is now covered. In the polyvinyl chloride spectrum a sharp, symmetrical band is observed at 1380 cm 'The intensity of this band is corrected in this way.

until the absorption ratio is proportional to the effective thickness of the film (K value).

The absorption of the corrected band at about 1338 cm 'is roughly proportional to the thickness of the film sample. The ratio of the absorptions A 1380 cm " ¹ to A 1338 cm ¹ represents the K value. The branching of the non-reduced polyvinyl chloride products is determined from the calculated K values (A 1380 / A 1338) and converted into the ratio CH ₃ / 1000 CH ₂ , based on the ratio 1.5 CH ₃ 1000 CH ₂ as the branching index of a commercial PVC ~ (Marlex 6050). The results of these determinations show that commercial or conventionally manufactured PVC materials have a K- Have a value in the range of 0.1200 and have a content of about 10 CH ₃ groups per 1000 CH ₂ groups, as can be seen in the summarizing Table II below The polyvinyl chlorides according to the invention have 10 to 13 CH ₃ groups 1000 CH ₂ groups.

The polymers of Examples 1, 2 and 3 as well as selected, conventionally produced polyvinyl chloride products with approximately the same average molecular weight are ^; In a nitrogen atmosphere in a known manner, each of which LiAlH _{4 is used} as a catalyst, subjected to the reducing hydrogenation. This method is described in detail by A. Nakajima et al in "Makromolekulare Chemie", 95, 1966, p. 40. The first reduction phase is carried out at 65 ° C. for 360 hours with tetrahydrofuran as the solvent. The second reduction stage is carried out at 100 ⁰ C using a tetrahydrofuran Dekalinmischung during 155 hours. After each reduction phase, the reduced polymer is obtained by pouring the reaction mixture into excess water, adding enough H ₂ SO ₄ until a pH of 2 is reached, and then filtering off the mixture. The polymer is washed repeatedly and then dried.

The branching values for the reduced polyvinyl chloride samples were obtained using the calibration curve A 1378 cm '/ A 1368 cm' = / (CH ₃ / CH ₂ ), which was established for the linear C ₁₆ C ₈₀ hydrocarbons. Details for obtaining this calibration curve are given by Bocca ίο, Α. et al, in "Makromolekulare Chemie", 108, 1967, pp. 218-233. Based on the measured A 1378 cm '. A 1368 cm 'values and the calibration relationship:

A 1378 / A 1368 = 20 (CH ₃ / CH ₂ ) + 0.2939C- ⁶⁶ - ¹⁴ '"^'" * ¹

the ratio of CH ₃ to 1000CH ₂ in the analyzed polyvinyl chloride samples was determined. The results for this are shown in Table 11.

Table II

sample

Conventional polyvinyl chloride
(red. visc. 1.55). "

Conventional polyvinyl chloride
(reduced viscosity 0.63)

8 percent by weight polyvinyl chloride
Chain transfer device (reduced viscosity 0.17)

Polymerisation temperature (C)

55

55

71-74 CH, 1000 (H ₂

not reduced
Polymer

9
9

10

reduced polymer

10.0 *)
10.0 *)
13th

continuation

sample Polymcrisationslcmpcralur
CC) CH _3/1000 CH ₂
not reduced
Polymer reduced polymer Product according to example 1
Product according to example 2
Product according to example 3 90
130
160 10
11th
13th 13th
23
27

·) CHj / 1000 CH ₂ values from the literature.

These results show that the vinyl chloride polymers according to the invention _{contain a higher percentage of CH 2} CI end groups than conventional polyvinyl chloride, which is evident _{from the larger number of CH 3} to 1000 CH _{2 found.}

The limiting viscosity number of the polymer samples was measured in tetrahydrofuran at 25 ^C using a modified Ostwald capillary viscometer.

The melting points of the reduced vinyl chloride polymers and those of polyethylene are mutually exclusive the same and were determined by the Perkin-Elmer differential calorimetry method found at three different heating rates. These experiments show that the reduced products have a polyethylene structure and that none during the reduction Breakdown of the chain took place.

In the following, number average and weight average molecular weights are given which by means of gel permeation chromatography for some of the polymers listed in Table II and which also ^{relate to the homopolymers produced at 100 and 120 °} C. according to the invention. The limiting viscosity number of the polymers is:

Table III

sample Polymerisation
lcmpcratur
C ¹ C) Low viscosity number
(dl / g) Af ", M. Conventional polyvinyl chloride
(reduced viscosity = 0.63)
Polyvinyl chloride 8 "/" Ketlen-
carrier
Polyvinyl chloride 16 "chains
carrier
Polymer according to example! 1 ....
Polymer according to the invention ....
Polymer according to the invention ....
Polymer according to Example 2
Polymer according to Example 3 .... 55
71 74
55
90
100
120
130
160 0.52
0.188
0.162
0.438
0.39
0.25
0.145
0.09 38000
36800
10200
36800
25100
17500
13000
10561 13600
5000
4100
18700
12500
9000
7800
6164

The values given show that the homopolymers according to the invention, the higher polymerization temperature have a higher average molecular weight than any of the conventional polymers, such as those made with chain transfer agents. The highly branched structure of these products is shown, however, in a significantly lower intrinsic viscosity number.

It can be considered certain on the basis of the molecular structure data found for the homopolymers it is assumed that the vinyl chloride polymer chains of random and graft copolymers, manufactured by the same process have a different structure than other similar ones Polymer chains that are obtained in a conventional manner. Support for this assumption are the various improved processing properties of these products.

Example 5

Production of a copolymer

A copolymer of vinyl chloride and propylene is produced in a 38 l stainless steel reaction vessel of the type described in Example 1. 11.3 l of deionized water and a solution of 72.6 g of polyvinyl alcohol in 3.6 l of water are added to the reaction vessel, whereupon the reactor is closed and, as in Example 1, is freed from oxygen. The reaction vessel is further charged with 8808 g of distilled vinyl chloride and with 272 g of propylene while stirring. The reaction mixture is heated to 100 ° C., whereupon a sufficient amount of deionized water is pumped into the reaction vessel until the pressure is 35 kg / cm ² . At this pressure the monomers are liquid. The reaction vessel is then in

essentially filled with liquid. While the stirring is continued, a solution of 20 ml of tert-butyl peroxypivalate solution according to Example 1 is pumped into the reaction vessel, then the reaction mixture is stirred for a further 15 minutes. Until the end of the polymerization, 10 ml of the catalyst solution are added every 10 minutes and water is pumped in in a similar manner as required to maintain the working pressure. The total reaction time is 2V ₂ '° hours. The total concentration of catalyst used is 0.23%, based on the weight of the monomer charge.

The copolymer is recovered, cleaned and dried as in Example 1. The yield is 90 "" of theory. The polymer has a reduced viscosity of 0.44 and contains approximately 3.0 percent by weight of polymerized propylene.

The use of the copolymer as a binder in polyvinyl asbestos flooring

A floor covering material which contains the copolymer and asbestos is produced according to the following approach: _Tci | _c

Copolymer 100

Butyl benzyl phthalate plasticizer ... 25

Epoxy type plasticizer 5

Fesler containing nitrogen

organic stabilizer 3

Calcium carbonate 360

Asbestos 120

Titanium dioxide 48

Stearic acid 0.5

The above-mentioned constituents are mixed with one another, the mixture is placed in a Banbury mixer and then treated ^{at a temperature of 148 to 163 ° C. for 3 minutes.} The hot-treated material is then placed Wai zenstuhl 2 into and processed at 121 ⁰ C. After the material treated for 5 minutes at this temperature has been mixed, it is peeled off as a thin, 3.175 mm thick skin. Another approach for similar purposes is processed in the same way. This other approach is the same, with the exception that instead of the vinyl chloride-propylene copolymer according to the above example, a conventional vinyl chloride copolymer (containing 15 percent by weight vinyl acetate), as is usually used for flooring, is used. The vinyl acetate copolymer has a reduced viscosity of 0.61.

Samples of the rolled pelts are taken from each batch in accordance with the regulations of the Revised Federal Specifications for Vinyl-Asbestos Floor Tile, L-T-00345 (COM-NBS), August 28, 1959. on Based on these regulations, the following results were obtained:

Table IV

properties

Notch test (McBurney)
Room temperature 46 ° C,
1 min. - 25.4 mm

plate

Vinyl chloride

Propylene copolymer

0.007

Vinyl chloride

Vinyl acetate

Copolymcrisal

Plalle Vinyl chloride properties Vinyl chloride Vinyl acetate Propvlcn- C'opolymcrisat C'opolymcrisat 0.00875 10 min. 26.4 mm 0.0085 0.021 30 sec -? 5.4 mm 0.014 Abrasion (taber) 0.40 g / 100 [beta] CycIen 0.23 Deflection test 194 Deflection, kg / cm ² . 213 7th Break angle, degrees 10

These values show that the copolymer according to Example 5 gives a floor covering from which one Specimen is harder and more resistant to abrasion than one that is known from the known Commercial polyvinyl asbesi flooring. The flooring material that comes with the copolymer made according to the example is more flexible, which is due to the application of a greater force when bending the specimen is clearly visible until it breaks.

In order to test the water resistance of the panels according to the above approaches, samples were taken from each Plate weighed and stored immersed in water for 1, 2 and 3 weeks at room temperature. At the end of each storage period, the samples were removed, wiping off most of the water released and weighed. The percentage of water absorbed during storage was determined on the basis of the weight differences, with reference to the original weight of the sample became. Using this method the following results are obtained:

Table V

Plaltcnprobc

Vinyl chloride-propylene copolymer

Vinyl chloride-vinyl acetate copolymer ..

Water absorption. %
storage

I week

0.35
0.90

2 weeks

0.60
1.17

3 weeks

0.78
1.43

0.007

One approach to producing a plate which contains the copolymer according to Example 5 is more resistant against moisture as such with a vinyl chloride-vinyl acetate copolymer des Prior art is produced. Accordingly, one made according to the present example should Keep the plate more true to size during use.

It is difficult to produce vinyl chloride-propylene copolymers using conventional methods, as long polymerisation lines, e.g. 18 hours or more, because of the low catalyst efficiency are needed. It is characteristic that only up to 70% are converted. The conventional Copolymers cannot be used as binders in batches in asbestos-containing flooring material are used because they are poor because of the temperatures used in their manufacture suitable for further processing.

Use as rigid foam "

Using the following approach, a rigid foam was made with the polymer according to Example I made: ~

Polymer 2500 parts

Liquid Organotin Mercaptide Stabilizer 75 parts

JO

The constituents are mixed with one another and milled at 235 ° C. for 5 minutes. The soft one Material is peeled off as a thin layer and shaped into tablets. The material made up of cubes is immersed in trichlorethylene for one hour, about 35 percent by weight of the Solvent were added.

The so treated cubes are in a 25.4 mm injection molding machine, which contains a simple artnite snail, processed. The machine has a 3.175 mm slot nozzle. The screw speed is 20 rpm and the temperature of the injection molding machine between the funnel and the nozzle is 93 to 177 ° C. The nozzle temperature is 146 ° C. The foam has a density of 0.320 g / ccm.

Use as a processing aid
for high molecular weight polyvinyl chloride

The following describes the use of the polymer according to Example 1 as a processing aid for a high molecular weight polyvinyl chloride (reduced viscosity 1.55).

An approach is put together according to which 80 parts of the high molecular weight polyvinyl chloride are used 20 parts of the polymer according to Example 1 come. Every 100 parts of the mixture are mixed with 3 parts a liquid organotin mercaptide stabilizer added.

The components are mixed with one another and treated for 5 minutes at 177 ° C. on a 2-roll mill. Part of the softened material is pressed at 177 ° C., the pressure increasing continuously to 3500 kg / cm ² and the pressing time is a total of 8 minutes. For comparison purposes, a batch which only contains the high molecular weight polyvinyl chloride and the stabilizer (3 parts to 100 parts polyvinyl chloride) is rolled and pressed in the same way.

Samples from each crimped batch are tested for strength according to ASTM D-638 64T. The results are as follows:

1.01 mm in diameter capillary is used, determined at 216 ° C. The results are as follows:

-Table VII

Table VI

55

Prüfarl

Tensile strength, kg / cm ²
Tensile modulus, kg / cm ² ..
Elongation at break,% ...

High molecular weight
Pochloride

Polyvinyl chloride mixture

536

255 10 ³
85

60

534

262 10 ³
93

The rheology of the melts of each of the above mixtures is measured with the Sieglaff-McKelvey rheometer, in which a 25.4 mm long and

Viscosity (Poisc) Shear speed High molecular mixture (see ¹ ) Polyvinyl chloride 10 ° 58 · 10 * 35-10 * 10 ¹ 17 · 10 * 11.4-10 * 10 ² 4.3-10 * 3.0 · 10 * 10 ³ 0.98-10 * 0.57-10 * Shear speed in case of melt fracture, see " ¹ 110 490

These results show that the blend containing 20 weight percent vinyl chloride homopolymer contains according to the invention, compared to that. their plastic only has a high molecular weight has, has significantly improved flow properties. Accordingly, they also have excellent ones Processing properties.

The use of the product according to the invention as a processing aid for other high molecular weight Plastics do not reduce the physical properties of the in any discernible way erleren. This is evident from the equivalent values for the properties in Table VI.

Example 6

According to this example, a vinyl chloride-vinyl acetate copolymer is produced at 10O ¹ 'C using the method and apparatus according to Example 1. After 1850 ml of deionized water, which contains 7 g of polyvinyl alcohol and 180 g of vinyl acetate monomer, have been added to the reaction vessel, the reaction vessel is closed and evacuated. The vinyl chloride (1020 g) is then added with stirring, whereupon the reaction mixture is heated to 100 ° C. and water is pumped into the reaction vessel until a pressure of 35 kg / cm ² (working pressure) is reached. Thereafter, dissolved tert-butyl peroxypivalate catalyst (as in Example 1) is added in proportions of 2 ml over the duration of the reaction. The total concentration of catalyst is 0.68 ", based on the total weight of the monomers introduced. The reaction lasts 45 minutes. The polymer obtained in 83" yield contains 13.6 percent by weight of polymerized vinyl acetate and has a reduced viscosity of 0.37.

This product has an excellent viscosity behavior in solution, as shown by the following results, obtained for differently concentrated solutions of this copolymer in methyl ethyl ketone have been revealed. The concentrations are based on the weight of the copolymers. To the Comparison are made for matching solutions of a conventionally prepared vinyl chloride copolymer, containing 13 to 15 weight percent vinyl acetate, the results are also reported.

Table VIII

Concentration of the solution
(Gcwichl)

Copolymer according to

example

Conventional
Copolymerisal

Viscosity, cP ")
15% I 20%

20th
39

41
78

71
194

based on the weight of the vinyl chloride contained. Similar extractions with hot toluene gave a soluble fraction. After the It was found that this fraction contains a percentage of chlorine that corresponds to the solvent Weight percentage of vinyl chloride contained in the graft polymer is equivalent. Because of From these results it can be assumed that the graft copolymer is not a free copolymer substrate contains more. However, straight vinyl chloride homopolymer can be used contain.

*) Determined with the Brookfield viscometer (Tired! RVl. using spindle # 3 at 100 rpm.

The low viscosity of the solution of the vinyl chloride-vinyl acetate copolymer according to example 6 its use for coatings on paper, in color batches and in other areas where flowable solutions of polymers with a large proportion of solids can be used advantageously close.

Example 7

Production of
Vinyl chloride graft copolymers

Using a 38 1 stainless steel reaction vessel made according to Example 1 equipped, a graft copolymer is prepared as follows:

A solution of 72.6 g of polyvinyl alcohol in 3600 ml of deionized water, 15.1 l of deionized water and 1816 g of ethylene-vinyl acetate copolymer containing 26 percent by weight of vinyl acetate (melt index = 3) is entered into the reaction vessel. After closing and cleaning the reaction vessel, as described in Example 1, 7264 g of distilled vinyl chloride are added, whereupon the reaction mixture is heated to 100.degree. Fully demineralized water is pumped in up to 35 kg / cm ^2.

Then 20 ml of a solution of tert-butyl peroxypivalate (40 g of catalyst are diluted to 200 ml with 95% ethanol) in the reaction vessel added, whereupon the reaction mixture is stirred for 15 minutes. During this time If the polymerization proceeds up to a 30 to 40% conversion, as is the case with the necessary addition visible from water. so that the reaction vessel remains essentially filled with liquid. Thereafter, 10 ml of the catalyst solution are added every 5 minutes until the polymerization is complete added; no further addition is necessary. The total reaction time is 90 minutes. The total concentration of the catalyst used for this experiment is 0.29 ". Based based on the weight of the vinyl chloride monomer charge.

After the polymerization has ended, the copolymer is recovered, purified and as in the preceding Examples dried. The yield of copolymer (8626 g) is slightly higher than 95% Theory.

Extraction tests were carried out on this copolymer with hot cyclohexanone. It has been found that the remaining, insoluble fraction (a copolymer based on the ethylene-vinyl acetate) contains at least about 60 "" chlorine, be-physical properties
the graft polymers

The physical properties of samples obtained by means of an injection molding machine using a copolymer are then determined -HA 100 (Newbury Industries, Newbury, Ohio). Deformation conditions: cylinder temperature 177 ° C; nozzle 165/171 ° C; mold: room temperature; injection pressure 84 kg / cm ² ; deformation cycle 30 seconds (injection), 10 seconds ( Filling), 5 seconds (hardening).

Table IX

Tensile strength, kg / cm ² 210-280

Tensile modulus, kg / cm ² ■ 10 ³ 8.4-13.6

Elongation at break

(ASTM D-638-64 T) 40

Izod impact strength

cm · kg / cm

Notch (ASTM D-256-56) .. about 49-54.5 Deformation Temp. at

18.5 kg / cm ² , ⁰ ° C

(ASTM D-648-56) 46-49

Brittleness at low temperatures,

⁰ C (ASTM D-746-64 T) ... 10

Self-extinguishing flammability

In comparison, a mixture of 80 parts of the homopolymer according to Example 1 with 20 Parts of the ethylene-vinyl acetate copolymer, which is rolled at 121 ° C, crumbly and not solid. The mixture cannot be pulled off the roller mill as a tough skin.

Mixtures of conventional polyvinyl chloride (reduced viscosity = 1.10) with 15 to 20 parts of the Ethylene-vinyl acetate copolymer are at 171 ° C rolled, peeled off as skin and deforml by means of pressure. Samples of this mixture have an average Impact strength of about 8.15 to 10.9 cm · kg / cm notch.

With calcium carbonate. Asbestos and glass fiber filled approaches are blended, milled at 140 ⁰ C for 5 minutes and then under pressure at 149 ° C and 70 kg / cm ² is deformed during a time period of 5 minutes. The physical properties of these briquettes are according to ASTM 638-64 T as follows:

Table X

C'alciumuarbonul 100 asbestos Glass
fiber 50 308 75 25th 28 242 501 401 108 59 478 312 57 69 66

Capacity
Weight parts

Tensile strenght,
kg / cm

Tensile module,
kg / cm ² · 10 ³

Deformation temp.
at 18.5 1CgZCm ² ,
(ASTM D-648-56)

Comparative experiment B
A. Manufacturing

The reaction vessel of Example 1 is charged with a solution of 4.8 g of polyvinyl alcohol in 1715 ml of water. After repeatedly pumping out the oxygen and topping up with vinyl chloride to atmospheric pressure, 613 g of vinyl chloride are fed in with stirring, and the sealed reaction vessel is then ^{heated to 100 °} C. so that a pressure of 23.8 kg / cm ^{2 is} established. 4 ml of a 20 "solution of tert-butyl peroxypivalate are then added with constant stirring. The onset of the polymerization reaction is noticeable by a pressure drop Minutes a total of 52 ml of the solution have been fed in, corresponding to a concentration of 1.7 "of peroxy compound, based on the amount of monomer used. At this point in time, the reaction vessel pressure has dropped ^{to 7 kg / cm 2.} The reaction mixture is stirred for a further 15 minutes at 100 ° C., then cooled and the polymer is separated off by centrifugation. After the usual washing and drying, a yield of about 80 "is obtained.

This polymer is colored reddish brown and contains numerous hard, dark brown colored lumps, which indicates a material decomposition already during the polymerization.

B. Testing of thermal stability

a) Both a sample of the polymer prepared according to Section A and a sample of the product from Example 1 are ^{heated to 150 °} C. in air, and the weight loss is then measured over 60 minutes. The results are shown graphically in FIG. 1, curve 1 relating to the comparative sample and curve 2 relating to the product according to the invention. It is evident that the latter has a very high stability (weight loss during 60 minutes at most 0.5%).

b) In a further stability test, both material samples are heated in air at a rate of 3 ° C./minute, and the weight loss is continuously monitored. The results are shown in FIG. 2 reproduced. Curve 1 again refers to the comparison sample, showing that decomposition starts at 150 ⁰ C. The sample of the invention, however begins only to decompose at about 225 ° C, the weight loss even at 250 ⁰ C is still very low.

C. Examination by means of DilTerential Calorimetry Analysis

In contrast, the comparative sample exhibited a second order transition point (transition into the glass state) at 64 ° C, the sample according to the invention at a higher value by 10 ⁰ C (74 ° C). This fact also speaks for the better processing properties.

For this purpose 2 sheets of drawings

Claims (3)

Patent claims marriage: 1. Branched, thermoplastic vinyl chloride _{polymers with CH 3} and 3 to 14 CHaCl end groups on the branches per 1000 CH, groups and a content of at least 50 percent by weight vinyl chloride units, obtained by suspension polymerization of vinyl chloride, a mixture of vinyl chloride and a comonomer or one Mixture of vinyl chloride and a solid polymer graftable with this in the aqueous phase in the presence of monomer-soluble, free radical-forming catalysts at temperatures of 90 to 165 ° C and under increased pressure, characterized in that they are maintained by polymerization during the entire reaction time hydrostatic pressures of 28 to 350 kg / cm ^{2 were} obtained. 2. Process for the preparation of vinyl chloride polymers containing at least 50 percent by weight vinyl chloride units by suspension polymerization of vinyl chloride, a mixture of vinyl chloride and a comonomer or a mixture of vinyl chloride and a solid polymer graftable with this in the presence of monomer-soluble, free radical-forming catalysts in the aqueous phase at temperatures of 90 to 165 ° C and under increased pressure, characterized in that the polymerization is carried out during the entire reaction time at hydrostatic pressures of 28 to 350 kg / cm ² . 3. The method according to claim 2, characterized in that the polymerization during the total reaction time when the polymerization vessel is essentially completely filled with liquid performs. 40