GB1597285A - Process for the continuous manufacture of vinyl chloride polymers - Google Patents

Abstract

Homopolymers, copolymers or graft polymers of vinyl chloride which contain at least 85% by weight, based on the total polymer, of polymerized vinyl chloride and which optionally contain further comonomers and/or graft polymers in copolymerized form are prepared continuously in aqueous emulsion in the presence of at least one water-soluble catalyst and in the presence of from 1.5 to 3.5% by weight, based on the monomer employed, of at least one water-soluble emulsifier. The water-soluble emulsifier used is at least one water-soluble salt of an aliphatic, saturated monocarboxylic acid of the formula I or a mixture of a salt as mentioned above with at least one sodium, potassium or ammonium salt of a sulphate- or sulpho-containing organic compound which is effective as an emulsifier. The substituents in the formula I are as defined in Claim 1. <IMAGE>

Description

(54) PROCESS FOR THE CONTINUOUS MANUFACTURE OF VINYL CHLORIDE POLYMERS (71) We, HOECHST AKTIENGESELLSCHAFT, a body corporate organised according to the laws of the Federal Republic of Germany, of 6230 Frankfurt/Main 80, Postfach 80 03 20, Federal Republic of Germany, do hereby declare the invention for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: The present invention relates to a process for the continuous manufacture of vinyl chloride polymers.

It is known that homopolymers copolymers and graft polymers of vinyl chloride have differing aptitudes for stabilization by known heat stabilizers, depending on the method of manufacture of the polymers. For example, emulsion polymers prestabilized with basic inorganic salts, such as sodium carbonate, may be stabilized with diphenyl-thiourea, especially when the subsequent processing temperatures are not excessive, for example below 200"C. In contrast, the stabilizing action of diphenylthiourea on suspension and bulk polymers of vinyl chloride is rather unsatisfactory.

Such differences are also observed when using known metal-containing stabilizers, for example lead compounds, barium/cadmium compounds and tin compounds, depending on the method of polymerization (emulsion, suspension or bulk polymerization) and even with one polymerization method, depending on the polymerization conditions, especially on the polymerization auxiliaries employed. When the polymerization formulation is altered to improve the aptitude for stabilization of the polymer product, this results very often in other disadvantages, such as poor yield and processability and reduced aptitude for stabilization with other types of stabilizer.

In order to avoid a multitude of polymer types which causes confusion and failure in the processing industry, which requires an undesirable extension of stock and thus reduces the profitability of production, it is clearly desirable to manufacture in a manner as economic as possible one type of polymer only, if possible, or at least very few types which can be stabilized as universally as possible for further processing. The present invention seeks to provide such a process.

German Auslegeschrift No. 1,223,553 describes a process for the polymerization of ethylenically unsaturated compounds in the aqueous phase in the presence of catalysts and salts of monocarboxylic acids having from 11 to 32 carbon atoms, of the formula

in which each of Rl and R2 is an alkyl group R3 is an alkyl group or a hydrogen atom, and two or three of the groups directly linked to the tertiary or quaternary carbon atom may be linked together (cycloalkyl groups being considered as alkyl groups). This process is said to be especially suitable for polymerization at temperatures below 10 C.

Among a multitude of ethylenically unsaturated monomers, vinyl chloride is cited, and in one Example there is described the homopolymerization of vinyl chloride by what is obviously a batch process. As emulsifiers, there are used sodium salts of unsaturated aliphatic monocarboxylic acids having from 11 to 32 carbon atoms, the carboxyl group of which is directly linked to a tertiary or quaternary carbon atom. There is no indication as to the precise sodium salt used.

German Patent No. 1,645,672 described a process for the polymerization and copolymerization of vinyl chloride in aqueous emulsion with the use of a polymer seed latex in the presence of water-soluble salts of aliphatic, saturated monocarboxylic acids branched in the alpha-position to the carboxyl group and having at least 8 carbon atoms, as emulsifiers. Suitable monocarboxylic acids have the formula given above, in which each R1 R2 and R3 may also be aryl or aralky groups. Monocarboxylic acids having from 11 to 28, especially 15 to 19, carbon atoms are advantageously used.

According to German Patent No. 1,745,561, the process of German Patent No. 1,645,672 may be carried out by using, instead of the monocarboxylic acid salts described above, the salts of monocarboxylic acids having the formula

in which Rl is a branched alkyl group, and R2 a linear or branched alkyl group or a hydrogen atom, at least 50%, preferably at least 80%, of R2 being hydrogen atoms, and the sum of the carbon atoms in R1 and R2, which may be linked to form a ring is at least 6.

As the Examples show the three processes relate without exception to batch (discontinuous) emulsion polymerization processes. When these processes are adapted to continuous emulsion polymerization of vinyl chloride, disadvantages occur, especially with respect to the space/time yield in relation to the aptitude of the polymer product of heat-stabiliation with lead bariumkadmium or tin stabilizers, as shown from the result of the Comparative Tests described below.

The present invention is based on the observation that some of the branched monocarboxylic acid salts described in German Auslegeschrift No. 1,223,553 and German Patents No. 1,645,672 and 1,745,561, when used in the continuous polymerization of vinyl chloride in aqueous emulsion, result in a surprisingly good aptitude for heat stabilization of the polymer products with lead, barium/cadmium or tin stabilizers, as well as high space/time yields in the polymerization.

The present invention provides a process for the continuous manufacture of homopolymers, copolymers or graft polymers of vinyl chloride containing at least 85% by weight (relative to the polymer) of polymerized vinyl chloride units, in aqueous emulsion, in the presence of at least one water-soluble catalyst. from 1.5 to 3.5% by weight (relative to the monomers) of at least one water-soluble emulsifier and, optionally, further polymerization auxiliaries, wherein the water-soluble emulsifier is a water-soluble salt of an aliphatic, saturated monocarboxylic acid of the formula

in which each of Rl and R2, which may be identical or different, is a linear or branched alkyl group having from 1 to 5 carbon atoms, or a mixture of such a salt with at least one sulfo-group-containing, organic emulsifier.

Because of the favorable properties conferred on the polymerization mixture during polymerization and on the polymer produced, and because of their simple preparation, there are preferred the water-soluble salts of those monocarboxylic acids of formula I in which R1 and R2 are identical and each is an alkyl group having from 2 to 4 carbon atoms.

Especially good results are obtained with salts of 2-hexyldecanoic acid.

Water-soluble salts of the monocarboxvlic acids are those the monocarboxylic acid anion of which dissolves in water at 50"C in an amount of at least about 0.5% by weight, relative to the solution. Preferably, the salts are those of alkali metals or of the ammonium-ion, optionally substituted by organic groups. Examples or organic substituents of the ammonium ion are from one to four of the following groups: alkyl groups having from 1 to 6 carbon atoms, alkylaryl groups having from 7 to 9 carbon atoms, hydroxyalkyl groups having from 2 to 4 carbon atoms, haloalkyl groups having from 1 to 6 carbon atoms, polyoxyalkyl groups formed by reaction with ethylene oxide or propylene oxide and having 2 and/or 3 carbon atoms in the polymerized alkoxy group. Alternatively, there may be used salts of monocarboxylic acids having at least two different monocarboxylic acid anion or at least two different cations. Furthermore, at least two water-soluble salts the monocarboxylic acid anion and the cation of which are different may be used together.

The water soluble salts are used in the polymerization in amounts of from 1.5 to 3.5% by weight, relative to the monomers. Below 1.5% by weight, latices which are sufficiently stable for further processing cannot generally be obtained, and above 3.5% by weight, the properties of the polymers, for example transparency, water-sensitivity, and physiological tolerability are impaired.

Preferred salts are the sodium, potassium, and ammonium salts, especially the sodium salts.

Especially good results are obtained when using from 1.5 to 2.8% by weight, relative to the monomers, of the above of monocarboxylic acid salts, mixtures of two or more thereof.

The monocarboxylic acids of formula I and the salts thereof may be prepared, for example by the reaction described by Guerbet (Angew. Chemie 64, 1952, pp. 213-220), in which generally a branched high molecular weight alcohol is formed first from two linear aliphatic alcohols with the use of an alkaline condensation agent and a dehydrogenation catalyst, according to the scheme:

R being an alkyl, cycloalkyl or arylakyl group.

This branched alcohol may then be oxidized by known methods, for example with chromic acid, to give the carboxylic acid, and the desired salts may be prepared therefrom.

In the Guerbet reaction, branched acids of the formula

are formed as by-products, and the reaction may be controlled in such a manner that about 50% of branched alcohol and about 50% of branched acid are obtained J. Amer. Chem.

Soc. 76, (1954), pp. 52-56). By using alcohols having different radicals R, corresponding branched high molecular weight alcohols having different radicals R are formed (Fette, Seifen, Anstrichmittel 71 (1969), pp. 215-218), from which caroboxylic acids having different radicals R and the salts thereof may be prepared.

It has been found that in addition to the good properties endowed by the process of the present invention, and without adversely affecting these properties, the aptitude for heat-stabilization with tin compounds, and the processability (gelling properties) of the polymer can be further improved when part of the water-soluble salts of the branched monocarboxylic acids of the formula I is replaced by the sodium, potassium or ammonium salts, preferably the sodium salts, of certain sulfo group-containing organic emulsifiers.

These latter compounds are used in an amount of from about 25 to about 85% by weight, relative to the total amount of emulsifier. The total amount of emulsifier in this case is from 1.5 to 3.5% by weight, preferably 1.5 to 2.8% by weight, relative to the monomers.

These sulfo group-containing organic emulsifiers are: (a) monoalkyl-sulfuric acid esters, the alkyl group of which is linear or branched and contains from 8 to about 20 carbon atoms. Preferred monoalkyl-sulfuric acid esters are those in which the alkyl group is linear and contains from 10 to 14 carbon atoms, or in which the alkyl group is branched and contains from 12 to 18 carbon atoms; (b) alpha-sulfocarboxylic acid alkyl esters, the carboxylic acid component of which has from 8 to about 20 carbon atoms, preferably 10 to 16 carbon atoms, and the alkyl groups of which are linear or branched and contain from 1 to 4 carbon atoms; (c) sulfosuccinic acid di-alkyl esters. the alkyl groups of which are identical or different, each alkyl group being linear or branched and containing from 6 to about 14, preferably 8 to 12, carbon atoms; and (d) sulfosuccinic acid mono-alkyl esters, the alkyl group of which is linear or branched and contains from 8 to about 20, preferably 10 to 16, carbon atoms.

Especially good results are obtained when such sulfo group-containing, organic emulsifiers are used in the form of their salts and in amounts of from 35 to 65% by weight, relative to the total emulsifiers.

The compounds (a), (b), (c) and (d) in the form of their sodium, potassium or ammonium salts may be used alone or as mixtures of any two or more thereof, so that the components of the mixture are different either in the cation of the salt or in the sulfo group-containing inorganic anion of the salt only, or in the cation and in the anion.

Generally, the emulsifiers or emulsifier mixtures used in accordance with the present invention are added with agitation to the polymerization mixture in the form of aqueous solutions. In order to improve their solubility, organic solvents, for example lower aliphatic alcohols, may be added to the water.

The polymerization is carried out continuously in aqueous emulsion in the presence of from 0.001 to 1% by weight, preferably from 0.01 to 0.3% by weight, (relative to the monomers), of radical-forming water-soluble catalysts. Suitable catalysts are peroxydisulfates, peroxydiphosphates, perborates of potassium, sodium and ammonium, hydrogen peroxide, tert.-butyl-hydroperoxide, and other water soluble peroxides, as well as mixtures of different catalysts. These catalysts may be used in the presence of from 0.001 to 1% by weight, relative to the monomers, of one or more reducing substances suitable for the formation of a redox catalyst system, for example sulfites, bisulfites, dithionites, thiosulfates and aldehyde sulfoxylates such as sodium formaldehyde sulfoxylate. The polymerization may be carried out in the presence also of from 0.05 to 10 ppm, relative to the metal cation of the salt and the monomers, of soluble metal salts, for example salts of copper, silver, iron, nickel, cobalt and chromium.

In addition catalysts and emulsifiers, the polymerization may be carried out also in the presence of buffer substances, for example alkali metal acetates, borax, alkali metal phosphates, alkali metal carbonates, ammonia and ammonium salts of carboxylic acids, as well as chain transfer agents, for example aliphatic aldehydes having from 2 to 4 carbon atoms, halogenated hydrocarbons, for example di- or trichloroethylene, chloroform, bromoform. methylene chloride and mercaptans.

Monomers which are suitable for copolymerization with vinyl chloride are for example the following: olefins such as ethylene and propylene; vinyl esters of linear and branched carboxylic acids having from 2 to 20, preferably 2 to 4 carbon atoms, such as vinyl acetate, vinyl propionate, vinyl butyrate and vinyl-2-ethyl-hexoate; vinyl halides such as vinyl fluoride. vinylidene fluoride and vinylidene chloride; vinyl ethers; unsaturated acids such as maleic, fumaric, acrylic and methacrylic acids and the mono- and diesters thereof with mono- and dialcohols having from 1 to 10 carbon atoms; and maleimide and the N-substitution products thereof having aromatic, cycloaliphatic and optionally branched aliphatic substituents.

For graft copolymerization, there may be used, for example elastomeric polymers obtained by polymerization of one or more of the following monomers: dienes such as butadiene and cyclopentadiene: olefins such as ethylene and propylene; styrene; unsaturated acids such as acrylic and methacrylic acids and the esters thereof with monoand dialcohols having from 1 to 10 carbon atoms; acrylonitrile; and vinyl compounds such as vinyl esters of linear and branched carboxylic acids having from 2 to 20, preferably 2 to 4 carbon atoms, and together with at least one of the above monomers, vinyl halides such as vinyl chloride, and vinylidene chloride.

Other suitable polymerization auxiliaries are described, for example by H. Kainer in Polyvinylchlorid and Vinylchlorid-Mischpolymerisate, Springer edition, Berlin/Heidelberg/ New York 1965, pp. 34 to 59.

After polymerization, the resulting polymers are obtained in the form of aqueous emulsions or, after drying, in the form of powders to which there may be added further substances for stabilizing them and/or for improving their processing properties.

Polymerization is generally carried out at a temperature of from 30 to 80"C, preferably from 40 to 700C, at a conversion rate of from 87 to 95%, preferably from 89 to 91%, relative to the monomers. The conversion percentage, in the case of continuous emulsion polymerization, is advantageously determined as described below.

The pH during polymerization is generally from 7.5 to 10.5.

The liquor/monomer ratio is advantageously chosen in such a manner that there are obtained latices having solids contents of from about 40 to 48%, preferably from 43 to 46etc.

After complete polymerization and substantial elimination of the unreacted monomers, the polymer is generally separated by evaporation of the water, for example in a spray-dryer. Optionally, the latex may be liberated before drying from part of the aqueous liquor by physical methods, for example ultrafiltration.

The process of the present invention is especially suitable for the manufacture of vinyl chloride homopolymers, copolymers and graft polymers having at least 85% by weight (relative to the polymer) of polymerized vinyl chloride units, and it is especially appropriate for preparing vinyl chloride homopolymers.

The process of the present invention enable the manufacture of vinyl chloride polymers which can be well and uniformly stabilized with a great number of important heat and light stabilizers, especially the known lead, tin, and blended barium/cadmium compounds, by the advantageous continuous emulsion polymerization method, and with high space/time yields. The emulsifier mixtures used in the process ensure an improvement of the aptitude of the polymer produced for being stabilized with tin compounds, and an improvement of its processing properties (gelling properties).

Known lead, tin and barium/cadmium stabilizers for vinyl chloride polymers are described, for example by F. Chevassus and R. de Broutelles, in The Stabilisation of Polyvinyl chloride, Edward Arnold Publ. Ltd., London 1963, pp. 102 - 129, and by J. Voigt, in Die Stabilisierung der Kunststoffe gegen Licht und Warm, Springer ed., Berlin/ Heidelberg/New York 1966, pp. 614 - 643.

The following Examples illustrate the invention.

The various values referred to in the Examples were determined as follows: K-value: according to German Industrial Standard DIN 53 726.

Unit weight: close to and downstream of the outlet orifice of the vessel in which the continuous polymerization is carried out, there is arranged a discharge opening having a diameter of 15 mm and which can be closed. The latex under pressure is discharged and foams because of its content of unpolymerized monomer. As soon as the foam current has become uniform, it is allowed to flow into a metal vessel which has been previously weighed and which contains exactly 2 liters when filled to the rim. When the vessel is completely filled, the overhanging foam is skimmed off and the vessel is weighed at once. The weight gain is the unit weight (U.W.) in grams. On the basis of the unit weight, the conversion rate is calculated according to the following equation: (U.W. = (U.W. - g1VC) x % solids Conversion (U.W. - glVC) x % solids/100 % + glVC + g2VC in which g1VC = (2 - U.W./1150 g/l) x 273"C x 2.78 g/l x p (273"C - 8"C + t) x 760 mm Hg % solids = solids content in the polymer dispersion in % by weight, less the content in % by weight (relative to dispersion) of polymerization auxiliaries which are not volatile at about 100"C with steam, g2VC = content of monomeric vinyl chloride determined by gas chromatography according to the head space method (Zeitschrift f. analyt. Chemie 255 (1971), pp. 345 - 350) in the depressurized polymer dispersion free from foam, t = polymerization temperature in "C, p = atmospheric pressure in mm Hg.

The % conversion of vinyl chloride copolymers is calculated in analogous manner, if VC in the above equations is replaced by the sum of the amounts of monomeric vinyl chloride and the comonomer(s).

Spaceltime yield: is determined by means of a defined amount of dry polymer (in tons) which is manufactured within one unit of time (in this case: 1 month, calculated as 658 hours of production) of uninterrupted, continuous polymerization in a closed chamber of defined volume (in m3; for example contents of a polymerization vessel). The space/time yield (STY) is indicated in moto/m3, and it is measured as follows: The polymer dispersion which has formed continuously within 24 hours about 3 days after the start of the polymerization is reduced to a residual moisture content of about 0.2 % by weight (relative to the polymer) by spraying in a hot air current having a starting temperature of 1700C, and weighed. The resulting amount is multiplied by 658/24 and divided by the contents of the polymerization vessel (in m3).

Aptitude for stabilization According to the following formulations: lead stabilization (Pb) rigid vinyl chloride polymer 100 parts tribasic lead sulfate 1.5 parts montanic acid glycol ester 0.5 part polyethylene wax (M.W.abt. 2000) 0.3 part plasticized vinyl chloride polymer 100 parts tribasic lead sulfate 1.5 parts montanic acid glycol ester 0.5 part polyethylene wax (M.W. abt. 2000) 0.3 part di-2-hexylethyl phthalate 20 parts tin stabilization (Sn) rigid vinyl chloride polymer 100 parts dibutyl-tin-bis-thioglycolic acid- 1.5 parts 2-ethylhexyl ester montanic acid glycol ester 0.5 part titanium dioxide 2.0 parts Bariumlcadmium stabilization (BalCd) plasticized vinyl chloride polymer 100 parts Ba/Cd-laurate, equimolar mixture 1.5 parts montanic acid glycol ester 0.5 part di-2-hexylethyl phthalate 20 parts 300 g each of polymer powder to be tested are intensely intermixed with the corresponding amounts of the other components of the formulation, and laminated without friction on a roller mill (diameter of the rolls 150 mm, length 350 mm) at a temperature of the rolls of 175"C and a speed of 11 rpm, until the material has discolored to dark brown and begins to stick. Every 5 minutes, a test specimen having a thickness of 0.3 mm is taken off the sheet, and the degree of discoloration is determined by measuring the Yellowness Index (YI. according to ASTM D 1925-70, 1970, Book of ASTM Standards, Part 27). The YI indicates the degree of discoloration relative to a defined standard of whiteness (magnesium oxide) while using a defined source of illumination (normal light C).

The starting color (SC) of the shaped articles made from the polymer powder is set by the YI of the first specimen after a 30 minutes laminating time in the case of lead and tin stabilizers, and after a 15 minutes laminating time in the case of barium/cadmium.

The long duration stability (LD) in minutes is set by that laminating time of the specimens where the YI exceeds 150 units for the first time.

Sheet formation time The sheet formation time is evaluated as a measure of the plasticizing speed (gelling property) of the PVC powder: 300 g of polymer powder are homogeneously mixed by means of a spatula with 4.5 g of tribasic lead sulfate (for example Naftovin T 3.

Metallgesellschaft AG), 1.5 g of montanic acid glycol ester (Wachs E, Hoechst AG), and 0.6 g of polyethylene wax (Wachs PA 520. Hoechst AG). This mixture is uniformly distributed over the gap (width 0.1 mm) of a two-roller mill the rollers of which have a diameter of 150 mm, a length of 350 mm and a surface temperature of 175"C, and rotate at 11 rpm in opposite direction to each other. Subsequently, the pair of rollers is separated step by step to open the gap to 0.7 mm in such a manner that the gradually thickening rough sheet always seals the gap in order to prevent the passage of the still unplasticized material.

Lamination is continued until all polymer powder is converted to a completely plasticized rough sheet. The time required to achieve this is the sheet formation time.

Examples 1 to 15 and Comparative Tests A to H are carried out as follows: The monomer or monomer mixture, a 2.6 5to aqueous solution of the emulsifier(s). and a 2 % aqueous solution of potassium persulfate are introduced continuously and separately into a vertically positioned autclave having a capacity of 500 liters and provided with a flat blade paddle agitator in its upper part. 0.95 kg of emulsifier solution and 0.03 kg of persulfate solution are added per kg of monomer(s). The temperature of the reaction mixture is maintained constant (see Table). The polymer dispersion which has formed is discharged from the lower part of the autoclave while measuring the unit weight (U.W.).

The polymer dispersion contains about 47 % by weight of solids, it is mechanically stable, and it is dried by spraying in an air current heated at about 1700C (starting temperature).

The unit weight is a measure for the conversion rate in the polymerization. The lower the unit weight, the higher the polymerization temperature may be chosen for an intended polymerization degree (K value), which means a favorable space/time yield /STY) and thus a profitable manufacturing process.

The following results were obtained (see Table): Examples Aptitude for stabilization No. Emulsifiers Pb Sn Ba/Cd Amount Polymeriz- plasticized rigid rigid plasticized Sheet rel. to Quantita- ation formation monomer tive temp. U.W. K-Value STY SC LD SC LD SC LD SC LD time % b.w. kind Ratio C g moto/m YI 30' min YI 30' min YI 30' min YI 15' min min 1 2.6 2-butyl-octanoic acid - 51 130 69 - 70 38 32 135 62 120 50 75 18 165 7.00 2 2.6 2-hexyl-decanoic acid - 53 115 69 - 70 48 30 135 53 120 51 75 23 165 7.75 3 2.6 2-octyldodecanoic acid - 53 115 69 - 70 48 24 135 48 120 45 75 26 165 8.25 4 2.6 HD acid 50/50 53 115 69 - 70 48 24 90 44 75 45 75 35 75 4.00 SB ester 5 2.6 HD acid 50/50 54 110 69 - 70 53 29 135 48 105 41 90 33 105 2.75 LS ester 6 2.6 HD acid 50/50 51 130 69 - 70 38 29 120 44 90 44 90 28 90 3.75 SBH ester 7 2.6 HD acid 50/50 53 115 69 - 70 48 26 135 50 105 44 90 30 105 3.45 SF ester 8 2.6 HD acid 15/85 53 115 69 - 70 48 31 105 62 75 20 105 10 45 6.50 LS ester 9 2.6 HD acid 30/70 51 130 69 - 70 38 22 120 55 75 35 120 25 60 4.25 SF ester 10 2.6 HD acid 60 40 54 110 69 - 70 53 25 135 44 120 36 75 24 90 4.00 LS ester 11 2 6 HD acid 75 25 53 115 69 - 70 48 36 150 45 135 55 75 53 105 4.50 SF ester 12 2.0 HD acid 60/40 54 110 69 - 70 53 21 150 41 120 37 90 14 105 4.30 LS ester Comparative tests Aptitude for stabilization Emulsifiers Pb Sn Be/Cd Amount Polymeriz- plasticized rigid rigid plasticized Sheet rel. to ation formation kind temp. U W K-Value SIY SC LD SD LD SC LD SC LD time monomer % b.w. C g moto m YI 30 min YI 30' min YI 30' min YI 15' min min A 2.6 Iso-octadecanoic acid acc. to G.P. 1 745 561 Ex 5 50 140 69 70 33 23 150 50 105 48 90 24 165 7.30 B 2.6 Iso-tridecanoic acid acc. to G.P. 1 745 561 Ex 1 50 140 69 70 33 24 135 53 105 48 75 56 105 6.00 C 2.6 Monocarboxylic acid "Versatic 1519" at U W @ 160 no polymerization possible acc. to G.P. 1 645 672 Ex 1 D 2.6 Lauric acid 49 150 69-70 29 27 165 57 150 39 120 38 165 8.00 E 2.6 SB ester 48 160 69-70 25 95 75 > 100 45 16 90 52 60 5.50 F 2.6 SBH ester at U.W. @ 160 no polymerization possible G 2.6 SF ester 50 140 69-70 33 88 60 > 100 45 18 120 40 60 5.25 H 2.0 LS ester 53 115 69-70 48 83 105 99 90 13 150 42 60 6.50 Examples (continued) No. Emulsifiers Aptitude for stabilization Amount Polymerizplasticized rigid rigid plasticized Sheet rel. to Quantitaation formation monomer tive temp. U.W STY SC LD SC LD SC LD SC LD time % b.w. kind Ratio C g K-Value moto m' YI 30' min YI 30' min YI 30' min YI 15' min min 13 3.2 HD acid 50 50 54 110 69 - 70 53 18 135 62 105 37 75 25 90 2.75 LS ester 14 2.0 HD acid 35 65 44 115 78 - 28 135 49 105 31 120 21 90 3.75 LS ester 15 2.0 HD acid 60/40 62 115 60 - 24 105 57 75 52 75 26 75 4.00 LS ester meanings of the Table: Column 4: quantitative ration in parts by weight rel. to the total emulsifier amount = 100 parts Column 3: symbols of the emulsifiers (the sodium salt being used in all cases) HD acid - 2-hexyldecanoic acid SB ester - di-isodecyl-sulfosuccinic acid ester LS ester - monolaurylsulfuric acid ester SBH ester - mono-isodecylsulfosuccinic acid ester SF ester - lauryl-&alpha;-sulfo-fatty acid methyl ester The word "Versatic" used in the Table is a registered Trade Mark

Claims (10)

WHAT WE CLAIM IS:

1. A process for the continuous manufacture of homopolymer, copolymer or graft polymer of vinyl chloride containing at least 85% by weight (relative to the copolymer) of polymerized vinyl chloride units, which comprises polymerizing the monomers in aqueous emulsion in the presence of at least one water-soluble catalyst and from 1.5 to 3.5% by weight (relative to the monomer(s)) of at least one water-soluble salt of an aliphatic, saturated monocarboxylic acid of the formula Rl (CH2)3 R2(CH2)5 - CH - COOH in which each of Rl and R2, which are identical or different, is a linear or branched alkyl group having from 1 to 5 carbon atoms, or a mixture of such a salt and at least one sulfo-group-containing, organic emulsifier.

2. A process as claimed in claim 1, wherein Rl and R2 are identical and each is an alkyl group having from 2 to 4 carbon atoms.

3. A process as claimed in claim 1 or claim 2, wherein the acid is 2-hexyldecanoic acid-1.

4. A process as claimed in any one of claims 1 to 3, wherein the sulfo-group-containing organic emulsifier is a sodium, potassium or ammonium salt of a monoalkylsulfuric acid ester, the alkyl group of which is linear or branched and contains from 8 to 20 carbon atoms, in an amount of from 25 to 85% by weight, relative to the total emulsifiers.

5. A process as claimed in any one of claims 1 to 3, wherein the sulfo-group-containing emulsifier is a sodium, potassium or ammonium salt of an alpha-sulfocarboxylic acid alkyl ester, the carboxylic acid component of which has from 8 to 20 carbon atoms and the alkyl group of which is linear and contains from 1 to 4 carbon atoms, in an amount of from 25 to 85% by weight, relative to the total emulsifiers.

6. A process as claimed in any one of claims 1 to 3, wherein the sulfo-group-containing organic emulsifier is a sodium, potassium or ammonium salt of a sulfosuccinic acid di-alkyl ester, the alkyl groups of which are identical or different, and each is linear or branched and contains from 6 to 14 carbon atoms, in an amount of from 25 to 85% by weight, relative to the total emulsifiers.

7. A process as claimed in any one of claims 1 to 3, wherein the sulfo-group-containing organic emulsifier is a sodium, potassium or ammonium salt of a sulfosuccinic acid monoalkyl ester, the alkyl group of which is linear or branched and contains from 8 to 20 carbon atoms, in an amount of from 25 to 85% by weight, relative to the total emulsifiers.

8. A process as claimed in any one of claims 4 to 7, wherein the emulsifier contains from 35 to 65% by weight relative to the total emulsifiers, of the sulfo-group-containing organic emulsifier.

9. A process as claimed in claim 1 carried out substantially as described in any one of Examples 1 to 15 herein.

10. A vinyl chloride homopolymer, copolymer or graft polymer whenever manufactured by a process as claimed in any one of claims 1 to 9 herein.