GB1577030A

GB1577030A - Preparation of vinyl halide polymers

Info

Publication number: GB1577030A
Application number: GB2165477A
Authority: GB
Original assignee: Hooker Chemicals and Plastics Corp
Current assignee: Occidental Chemical Corp
Priority date: 1976-06-17
Filing date: 1977-05-23
Publication date: 1980-10-15
Also published as: BE855764A; DE2727234A1; IT1080205B; NL7706428A; FR2355034A1; ES459904A1; JPS52154887A; BR7703894A

Description

(54) PREPARATION OF VINYL HALIDE POLYMERS (71) We, HOOKER CHEMICALS & PLASTICS CORP, a Corporation organised and existing under the laws of the State of New York, United States of America of Niagara Falls, State of New York, United States of America, 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: This invention relates to a method of preparing a polymer of a vinyl or vinylidene halide containing a mixture of stabilizer, lubricant and processing aid incorporated in the resin during the bulk liquid phase polymerization of the vinyl or vinylidene halide monomer.

Vinyl or vinylidene halide homopolymers and copolymers, being characterized by excellent moldability, corrosion resistance e.g. to acids, and resistance to combustion, are widely employed in the preparation of fabricated resin articles such as phonograph record discs, building panels, pipes, blown bottles and films. The fabrication or processing of the base polymer to such articles generally involves extrusion, calendering or molding of the molten resin at elevated temperatures so that it is necessary to add to the resin, before such processing, at least one of each of the following classes of additives: light and/or thermal stabilizer, organic lubricant and organic processing aid, the chemical structural identity of each class of additive being well known to the art.

The stabilizer protects the resin from degradation by light and/or heat, such as the heat used in processing or fabricating the resin.

The lubricant decreases the adhesive forces between the polymer melt and the surfaces of the processing equipment (external lubrication) and/or lowers the fusion rate of the polymer in the processing equipment and decreases the internal friction of the molten polymer (Internal lubrication).

T e processing aid increases the hot elongation and hot tear strength of the resin melt in the processing equipment and eliminates plate out of the polymer on the surfaces of the processing equipment.

The aforementioned additives are conventionally added to the resin after completion of polymerization by methods involving intense mechanical working at elevated temperatues in the range of 80" to 1800C. as for example on a roller mill or in high intensity mixers, followed by cooling. While this method is widely employed in industry for making vinyl or vinylidene halide resin compositions, it is highly disadvantageous since it (a) requires subjecting the resin to elevated temperatures thereby introducing potential instability which may show up during later fabrication of the resin; (b) results in resin compounds of unsatisfactory homogeneity; (c) creates a serious pollution problem since the resin normally contains traces of unreacted vinyl or vinylidene halide monomer which escapes into the surroundings during the elevated temperature working of the molten polymer to incorporate the additives.

It is known to add one or more additives to the polymerization reaction thereby overcoming the aforementioned deleterious effects of post-polymerization addition of stabilizer, lubricant and processing aid (see for example Specifications Nos. 1463737 and 1519610). However, the prior art has not contemplated or suggested the addition of the present mixture of additives to an on-going vinyl or vinylidene halide polymerization which is carried out by a polymerization mode consisting exclusively of bulk liquid phase reaction, i.e. polymerization without the addition of a solvent, as in solution polymerization, or a diluent such as water as in aqueous suspension or emulsion polymerization or such as empty space as in the vapor phase mode of polymerization. As pointed out by R. W. Lenz, "Organic Chemistry of Synthetic High Polymers", Interscience Publishers, 1967, page 359, it is well established in the art that the behaviour of a polymerization reaction and the properties of the resulting polymer can vary greatly according to the nature of the physical system, i.e. mode in which the polymerization reaction is carried out. Thus a prediction of the results of a bulk liquid phase vinyl or vinylidene halide polymerization from the results of a corresponding or similar reaction by a non-bulk mode of polymerization is not feasible.

W.M. Reiter et al., U.S. Patent 3,862,066, discloses the liquid phase polymerization of vinyl halide, e.g. vinyl chloride, by the aqueous suspension reaction mode in the prespence as additives, of dissolved or dispersed lubricant and stabilizer and at least one other additive selected from dispersed pigment and polymer modifier which according to the reference includes both an organic processing aid for the polyvinyl halide and an organic impact modifier for the polyvinyl halide. This reference does not teach or suggest bulk liquid phase vinyl halide polymerization in the presence of stabilizer, organic lubricant and organic processing aid since suspension polymerization, albeit a liquid phase reaction, is distinguished from bulk liquid phase polymerization in its kinetics, product morphology and product structure as pointed out by J.H.L. Henson et al., "Developments in PVC Technology", J.

Wiley and Sons, 1973, pages 18-26 and p.38, last line.

B. E. Johansson, U.S. Patent 3,899,473 teaches vinyl halide polymerization in the presence of solid additives, i.e. heavy metal fatty acid soap thermal stabilizers, pigments and/or coupling agents which are appropriate adjuvants for polyvinyl halide. In this process, polymerization is first carried out in a bulk stage until 20% conversion of the monomer is obtained and then completed in the presence of water and water soluble suspension aids by the suspension mode of polymerization. This patent does not disclose polymerization in the presence of the mixture of stabilizer, lubricant and processing tid and is essentially a suspension polymerization in which a bulk stage is provided prior to introduction of the water and suspension aids for the purpose of omitting certain surface active agents, required when solid additives are charged to a conventional suspension polymerization. Accordingly the patentee does not teach or suggest the bulk liquid phase vinyl halide polymerization of the present invention.

The prescnt invention relates to a process for preparing a vinyl or vinylidene halide polymer copolymers having incorporated therein a mixture of a small effective amount of at least one inorganic or organic heat and/or light stabilizer for the polymer, a small, effective amount of at least one organic lubricant for the polymer, and a small effective amount of at least one organic processing aid for the polymer and optionally still other additives used in vinyl or vinylidene halide polymer compounds. Surprisingly it has been found that the incorporation of such additive mixtures into the polymer by carrying out the bulk liquid phase polymerization of the monomer in the presence of such additive mixtures does not substantially lower the yield of polymer product or diminish the functional effect of each individual additive. Thus the present process provides a polymer product in conversions of at least 30% based on the weight of monomer reactant charged and usually of 60%or even 70% to 85% based on the weight of monomer reactant charge. Furthermore the product obtained by the present process is homogeneous and characterized by excellent stability against light and heat-induced degradation, excellent lubricity, and improved processability i.e. improved hot elongation and hot tear strength without substantial plate out, i.e. the individual additives retain their individual functional effects in the product. The present process avoids the necessity of milling or working the polymer product at elevated temperature to incorporate the additives and thereby avoids introduction of the aforementioned instability characteristics of conventionally prepared polymer-additive compounds and the pollution problem associated with escape of unreacted vinyl or vinylidene halide monomer from the resin to the surroundings during the elevated temperature milling operation.

By the process of the invention, the present additive mixture is incorporated in the vinyl or vinylidene halide polymer in a bulk polymerization process which can be either a single stage or a two-stage bulk polymerization process, in which, during a first stage, 3 to 15% polymerization takes place, preferably 7 to 12% by weight of the monomer or monomers, are converted using high speed agitation, followed by polymerization in a second stage wherein low speed agitation is used until 30% to 85% of the reaction mixture has been converted to polymer as described in British Patent 1,047,489 and Thomas, U.S. Patent 3,562,237.

The preferred method of the invention contemplates the addition of conventional stabilizer, lubricant and processing aid for vinyl or vinylidene halide polymers with the monomers to be polymerized followed by a liquid phase bulk polymerization process to provide a polymer characterized by improved heat and light stability lubricity and processability.

The additives can be added at the beginning of the bulk polymerization process which can be a single stage process or a two stage process described above or at a convenient stage of the process. Thus, where a two-stage process is used, in which preferably 7 to 12% by weight of the monomer or monomers are converted, addition of the additives can occur prior to the transfer of the combination of monomer and polymer into the second stage polymerization vessel.

If desired, one or more components of the additive mixture of the invention can be added to the first stage with remaining components of the mixture being added after the first stage but before or during the second stage of the polymerization. Conveniently, for example the stabilizer or the stabilizer and the lubricant can be added before or in the first reaction stage with the remaining components of the additive mixture, being added later, i.e. after the first stage but before or during the secind stage of the polymerization.

The amount of each additive employed in the practice of the invention is the amount conventionally employed when the additive is incorporated in the polymer according to the conventional addition technique, i.e. by physical mixing subsequent to completion of the polymerization reaction. In general sufficient amounts of additives are used to provide 0.01 to 5 weight percent of the additive based on the weight of the resin with preferred amounts of each additive being 0.1 to 3 weight percent of each stabilizer, 0.1 to 1.0 weight percent of each lubricant and 1 to 3 weight percent of each processing aid.

Stabilizers suitable for use in making the vinyl or vinylidene halide polymer compound in accordance with the improved method of the present invention include all of the materials known to stabilize vinyl or vinylidene halide polymers against degradation action of heat and/or light. They include all classes of known stabilizers, both organic and inorganic such as metal salts of mineral acids, salts of organic carboxylic acids, especially of carboxylic acids of 6 to 18 carbon atoms. organo-tin compounds, epoxides, amine compounds and organic phosphites.

Inorganic stabilizers suitable for use as stabilizers in the improved method of the present invention include salts of mineral acids such as carbonates, for example sodium carbonate and basic lead carbonate; sulfates, such as tribasic lead sulfate monohydrate and tetrabasic lead sulfate; silicates, such as coprecipitated basic lead silicate sulfate, lead ortho-silicate, the silicates of calcium, barium and strontium; phosphates. such as trisodium phosphate. tetrasodium pyrophosphate. sodium hexametaphosphate. dibasic lead phosphate and sodium monohydrogen phosphate; phosphites, such as sodium and potassium phosphite, dibasic lead phosphite, and barium/sodium phosphite.

Typical salts of organic carboxylic acids suitable for use as stabilizers in the present invention include stearates, laurates, caproates ricinoleates and undecylates of metals such as lead, cadmium, manganese, cerium, lithium, strontium, sodium, calcium, tin (stannous and stannic), barium, magnesium, especially dibasic lead stearate, and the stearates and laurates of cadmium, barium, calcium, strontium, magnesium, tin and lead, as well as the salts of other aliphatic, monocarboxylic acids, unsaturated acids and diacids of the abovementioned metals, such as those of 2-ethylhexoic, 2-ethylbutyric, 2-methyloctanoic, maleic, triethylmaleic and monocyclohexylmaleic acid, including the aconitates, itaconates, and citraconates of barium, cadmium and zinc. Typical carboxylate salts also include the calcium, zinc, cadmium, barium, and tin carboxylate salts of alpha olefinmaleic anhydride condensates disclosed in G. C. Hopkins and D. B. Merrifield, U.S. Patent 3,933,740. Further included are the metal salts of aromatic acids such as phthalates, naphthenates, and salicylates, including basic lead phthalate, tin phthalate, strontium naphthenate, cadmium naphthenate, barium diisopropyl salicylate and calcium ethylacetoacetate. Some of the abovementioned stabilizers, as, for example, the above-described metal salts of organic carboxylic acids of 6 to 18 carbon atoms, especially the stearates and laurates of lead, cadmium, manganese, lithium, strontium, sodium, calcium, tin, barium, and magnesium, also function as lubricants as described herein below so that such metal carboxylate salts when employed in a stabilizing amount according to the invention will also serve as the lubricant.

Suitable organo-tin stabilizers include mono-, di- and tri- organo-tin esters of mercapto-substituted carboxylic acids, more particularly described by structural formula definition in the aforementioned U.S. Patent 3,862,066 of Reiter et al. (at the passage running from column 6, line 40 to column 7, line 2) and U.K. Specification No. 1519610.

Specific examples of suitable organo-tin stabilizers include di-n-butyl tin S,S'-bis (iso-octyl mercaptoacetate), di-n-octyl-tin S,S'-bis (iso-octyl mercaptoacetate , di-nbutyl tin bis (monomethylmaleate , di-nbutyl tin bis- (isooctyl thioglycolate), di-nbutyl tin bis-mercaptopropanoate, di-n-butyl tin bis-(2-ethylhexanoate) , di-n-butyl tin bis-(isobutyl thioglycolate), di-n-butyl tin diacetate, di-n-butyl tin stearate, tri-n-octyl tin laurate, n-butyl tin tris-(isobutyl thiog lycolate). tri-n-butyl tin isobutyl thinglyco- late. n-butyl tin triacetate, and mixtures thereof.

Suitable epoxide stabilizers include the glycidyl ethers, including those of allyl alcohol and its polymerizates as well as those of diethylene glycol, glycerine, naphthol, resorcinol, diisobutylphenol, tetraphenylol methane and diphenyl propane (Bis-phenol A). Also included are the reaction products of Bisphenol A glycidyl monoether with epichlorohydrin; the glycidyl alcohol esters, such as glycidyl oleate and glycidyl laurate; and, importantly, unsaturated epoxy esters, especially those based on natural glycerides or the esters of natural or artificial acids and synthetic alcohols. Within this latter class are included natural epoxidized oils such as epoxidized soy bean, linseed and cotton seed oil; epoxidized tallow and lard; the products of esterification of an epoxidized fatty acid and a synthetic alcohol, and completely synthetic esters such as epoxyalkylsuccinic acids. Exemplary specific epoxy stabilizers include methyl epoxystearate, butyric ester of epoxidized soya-bean oil, tetrahydro furfuryl-ester of epoxidized soy-bean oil, epoxystearate of monobutyl ether of diethylene glycol, cyclohexyl epoxy stearate, 2-ethyl-butyl epoxystearato. 2-ethyl-hexyl epoxystearate, methoxy-ethyl epoxystearate, phenyl epoxystearate, butyl epoxytallate, sorbitanpolyoxy-ethylene triepoxystearate, hexyl epoxystearate, and others.

Also suitable are the metal salts of epoxidized fatty acids. especially the zinc. cadmium, strontium, barium or lead salts of epoxy stearic acid. acids extracted from cotton seed oil and epoxidized soy-bean oil. Further epoxy-type stabilizers include the epoxy derivatives obtained by multistep procedures starting with cyclohexane such as, for example. 9-1 0-epoxystearate of 3.4 cpOxycyClohexylmeth ane. 9 l O-dic poxpste a rate of 3.4epoxy cyclohex ylmcthanc, and iso-octyl- 9-10 epoxystearate.

All of the above-listed epoxide stabilizers have some lubricating properties so that they also function, and are suitable for use as lubricants in the improved method of the present invention. The epoxides of the aforementioned unsaturated naturally occurring oils also function as plasticizers as described heicia hclol.

Suitable amine stabilizers include diphenyl amine, thioiiica. aryl thiourca. N.N'-bis-(o -hydroxypbenyl)urea, N-phenyl-N' -(p-dimethylaminophenyl) thiourea, alkyde resins resulting from condensation of mono-.

di- or triethanolamine with unsaturated acids particularly maleic acid. 2-phenyl-indole, N,N' bis-carboethoxy- isopropanol urea.

monophenyl urrea. monophenyl thiourea, diphenyl thiourca. betaethyl aminocrotonate. esters of acid betaaminocrotonate.

condensation products of substituted amines and diacids. and of ethanolamine and unsaturated acids.

Suitable organic phosphite stabilizers include triphenyl, trioctyl, tricresyl mono- or dialkyl or aryl phosphites and mixed salts thereof, such as cadmium alkylaryl phosphite, cadmium alkyl phosphite and zinc alkylaryl phosphite, An especially preferred class of phsophite ester stabilizers are the tris (alkyl phenyl) phosphites having 8 to 12 carbon atoms in the alkyl substituents such as the tris (p-nonyl-phenyl), -the tris(pdecylphenyl), -tris(octylphenyl)-, and the tris(p-dodecyl) phosphite esters.

As is well known to those skilled in the art, stabilizers are often employed in combinations of two or more of the above-mentioned stabilizers, and the term "stabilizer" as used in the specification and claims is intended to denote single stabilizers as well as combinations of two or more stabilizers.

A detailed description of stabilizers and stabilizer combinations suitable for use in polyvinyl halide, including those herein discussed as suitable for use in the method for making vinyl halide polymer compounds, is found in F. Chevassus and R.de Bru̥telles "The Stabilization of Polycinyl Chloride," St. Martin's Press, New York, 1963, p. 101168.

Advantageously the stabilizers employed in the invention are substantially water insoluble so as to resist being leached from the polymer product when the latter is in contact with ambient moisture.

Preferably also the stabilizers employed in the invention are organic compounds, and of these the salts of carboxylic acids, especially monocarboxylic acids, with calcium, magnesium, strontium, barium, manganese, cadmium, zinc, lead and tin (stannous and stannic) are especially preferred, mixtures of zinc and calcium salts providing an especially good result.

The aforementioned metal carboxylate salts are especially effective when employed as primary stabilizers in the presence of the aforementioned organic phosphites or epoxy compounds as secondary or supplementary stabilizers.

The lubricants contemplated for use in the process of the invention include natural and synthetic waxes such as carnauba wax; montan wax; paraffin wax; low molecular weight polyethylene; oxidized polyethylene based on low density or high density polyethylene; long chain fatty alcohols such acetyl and stearyl alcohols; high molecular weight fatty acids containing from 6 to 20 preferably 8 to 18 carbon atoms and their metal salts and esters. such as. for example. aluminum stearate, barium stearate, calcium stearate, lead stearate, lithium stearate. magnesium stearate. cadmium stearate. cetyl palmitate. glyceral monostearate. zinc stearate, stearic acid, myristic acid, n-butyl stearate, ethyl palmi tate and glyceryl tristearate; further, amides derived from fatty acids, such as stearic acid and specifically N,N'-ethylene -bis-stearamide. Specific examples of preferred lubricants include paraffin wax, low molecular weight polyethylene, oxidized polyethylene based on high density or low density polyethylene, calcium stearate, and N,N'-ethylene -bis-stearamide. All of the above listed materials are commercially available specifically for use as lubricants in vinyl or vinylidene halide polymer compositions. The presence of one or more lubricants in the polymer compounds is critically required in order to prevent sticking of the compound during processing and to decrease internal and external friction, and consequently heating of product due to mechanical work, thereby reducing the heat history and contributing to stability of the finished article.

Individual lubricants may predominate in contributing either an external lubrication effect or an internal lubrication effect to the polymer in which they are incorporated. For this reason, it is generally advantageous to employ a mixture of a lubricant or lubricants which contribute predominantly an external lubrication effect with a lubricant or lubricants which contribute predominantly an internal lubricant effect. Typical of lubricants which have predominantly an external lubricating effect on the polymer are stearic acid and its salts with calcium, lead, cadmium and barium, myristic acid, paraffin wax, low molecular weight polyethylene and ethyl palmitate. Typical lubricants, which have predominantly an internal lubricating effect on the polymers in which they are incorporated, include glyceryl esters of fatty acids of 12 to 18 carbon atoms such as glyceryl monostearate, long chain fatty alcohols such as stearyl alcohol and cetyl alcohol and the esters with long chain aliphatic carboxylic acids such as cetyl palmitate. A more particular description of lubricants for use in vinyl halide polymers is set forth in Henson et al.

op. cit. p. 42-44 and G. Mathews, "Vinyl and Allied Polymers" CRC Press, Vol. 2, 1972, p. 117-119,141.

The organic processing aid contemplated for use in the process of the invention for incorporation into a vinyl or vinylidene halide polymer according to the invention is typically a polymer of a lower alkyl ester of acrylic acid or methacrylic acid, e.g. methyl methacrylate. Copolymers of a lower alkyl acrylate and a lower alkyl methacrylate, (wherein lower alkyl signifies 1 to 6 carbon atoms) such as the copolymer containing about 13% by weight ethyl acrylate and 87% by weight methyl methacrylate, can be used as processing aid additives also. Other typical processing aids well known in the art include acrylonitrile-styrene copolymers and methyl acrylate-butadiene- styrene-based terpolymers. The chemical structure of organic processing aids suitable for use as additives in polyvinyl halide (many of which are available commercially only as proprietary materials) is more particularly discussed in L. Mascia, "The Role of Additives in Plastics", J. Wiley and Sons, 1974, p. 36, P.F. Briuns Ed., "Polyblends and Composites", Interscience Publishers, 1970, page 166; C.F. Ryan, SPE Journal24 89 (1968), R. J. Grochowskietal.

U.S. Patent 3,833,686, and E. C. Szamborski et al., Kunstoffe 65 29 (1975).

Additional classes of additives for vinyl or vinylidene halide resins which optionally can be added with the stabilizers-lubricant -processing aid additive mixture during bulk polymerization according to the invention include organic impact modifiers, organic plasticizers, pigments including dyes, fillers, flame retardants, and ultra-violet screening agents.

Organic impact modifiers include rubbery polymers especially those with a glass transition temperature below room temperature, i.e. 25"C., including, as typical examples, chlorinated polyolefins such as chlorinated polyethylene, interpolymers of butadienestyrene and an ethylenically unsaturated polar organic monomer such as acrylonitrile and lower alkyl esters of acrylic and methacrylic acid. Nitrile rubber and ethylene vinyl acetate copolymers can also be employed. to increase the impact resistance of the polymer. The chemical structural identity of organic impact modifiers suitable for use with polyvinyl halide is more particularly described by T. O. Purcell et al. in Plastics Engineering, April 1976, p. 46-49; P. F.

Briuns, Ed. op cit, p. 166-176, and aforementioned U.S. Patent 3,862,066 et al. Generally the amount of the organic impact modifier added according to the invention is sufficient to provide a concentration of 5 to 20 weight percent, preferably 8 to 15 weight percent, of impact modifier based on the weight of the polymer.

The plasticizer optionally employed as an additive according to the invention is typically a phenyl dicarboxylic acid ester of an aliphatic alcohol of 6 to 11 carbon atoms such as di-(2-ethylhexyl)phthalate, diisooctyl phthalate, di-n-octyl phthalate, diisononyl phthalate, an elastomer such as nitrile rubber, a phosphate ester such as octyl diphenyl phosphate and cresyl diphenyl phosphate or an epoxy derivative of an unsaturated naturally occurring ester such as epoxidized linseed and soy bean oils, the latter also functioning as stabilizers as pointed out hereinabove. The chemical structure and technology of organic plasticizers suitable for use with polyvinyl halides are more particularly discussed in L. R. Brecker Plastics Engineering, March 1976, "Additives"76", p. 5. Generally the amount of plasticizer employed is sufficient to provide 1 to 30 weight percent plasticizer based on the resin.

Pigments, including dyes added in the bulk polymerization process of the invention include as typical examples inorganic pigments such as titanium dioxide, chrome yellow, chrome orange, molybdenum orange, strontium chromite, the iron oxides, chromium oxides, cadmium sulfoselenide, ultramarine blue, carbon black and metal powder pigments such as bronze powder.

Organic pigments such as copper phtholocyanine, Benzidene Yellow Toners and Indanthrene Blue R S as well as organic lake dyes such as Permanent Red 6R, can also be used in the invention. Pigments suitable for use with polyvinyl halide compositions are more particularly described in L.R.

Brecker op cit p. 3-4, in aforementioned U.S.

Patent 3,862,066, in F. Chevassus et al., op.

cit. p. 2424-253 and in aforementioned U.S.

Patent 3,899,473. The pigments are charged to the polymerization reaction in an amount sufficient to provide a concentration of 0.01 to 30 weight percent based on the weight of the resin.

The fillers employed as optional additives in the invention are typically silicon dioxide, silicate minerals, such as kaolin, asbestos and talc, aluminum oxide, calcium carbonate and titanium oxide which can also function as a pigment. Filler materials, which are more particularly described in Reiter et al. U.S.

Patent 3,862,066, Johansson 3,899,473 and L. R. Brecker op. cit. p. 4, are employed in the invention at concentrations of 1 to 30 weight percent based on the weight of the polymer.

Flame retardant agents which are optionally added to the bulk polymerization process of the invention, include iorganic flame retardants such as antimony trioxide and aluminum trihydrate and organic flame retardants such as organic phosphate esters such as octyl diphenyl phosphate which, as pointed out above, also impart a plasticizing effect to the polymer. Generally the amount of fire retardant agent employed is 0.1 to 5 weight percent based on the weight of the polymer.

Ultra-violet screening agents are optional additives which provide additional protection to resin exposed to extreme ultra-violet light by absorption or by energy-transfer.

Typical suitable ultra-violet light screening agents for vinyl or vinylidene halide polymers include phenyl salicylate, 4-tert-butyl phenyl salicylate. 2,2'di-hydroxy-4,4' -dimethoxy benzophenone, tri-pchlorophenyl stilbene, 2(2'-hydroxy-5methyl phenyl) benzotriazole and carbon black, the latter additive also functioning as a pigment as described hereinabove. Ultraviolet screening agents suitable for use as additives in polyvinyl halide resins are more particularly described in F. Chevassus and R.

de Broutelles, in amounts less than 10% by weight of the total monomer materials used in preparing the polymer. Suitable ethylenically unsaturated comonomers which can be used to form copolymers, terpolymers, interpolymers and the like, are illustrated by the following monoolefinic hydrocarbons, i.e. monomers containing only carbon and hydrogen, including such materials as ethylene, propylene, 3-methylbutene-1, 4methyl-pentene-1, pentene- 1, 3,3dimethylbutene- 1, 4,4-dimethylbutene- 1, octene- 1, decene- 1, styrene and its nuclear alpha-alkyl or aryl substituted derivatives, e.g., o-, m- or p-methyl, ethyl, propyl or butyl styrene; alphamethyl, ethyl, propyl or butyl styrene; phenyl styrene, and halogenated styrenes such as alphachlorostyrene; monoolefinically unsaturated esters including vinyl esters, e.g. vinyl acetate, vinyl propionate, vinyl butyrate, vinyl stearate, vinyl benzoate, vinyl-p-chlorobenzoates, alkyl methacrylates, e.g. methyl, ethyl, propyl and butyl methacrylate; octyl methacrylate, alkyl crotonates, e.g. octyl crotanate; alkyl acrylates, e.g. methyl, ethyl, propyl, butyl, 2-ethyl hexyl, stearyl, hydroxyethyl and. tertiary butylamino acrylates; isopropenyl esters, e.g. isopropenyl acetate, isopropenyl propionate, isoprdpenyl butyrate and isopropenyl chloride; vinyl esters of halogenated acids, e.g. vinyl alphachloroacetate, vinyl alpha-ebloropropionate and vinyl alphabromopropionate; allyl and methallyl compounds, e.g. allyl chloride, allyl cyanide, allyl chlorocarbonate, allyl nitrate, allyl formate and allyl acetate and the corresponding methallyl compounds; esters of alkenyl alcohols, e.g. beta-ethyl allyl aclohol and beta-propyl allyl alcohol; halo-alkyl acrylates, e.g. methyl alpha-chloroacrylate, ethyl alpha-chloroacrylate, methyl alphabromoacrylate, ethyl alphabromomoacrylate, methyl alphafluoroacrylate, ethyl alpha-fluoroacrylate, methyl alpha-iodoacrylate, and ethyl alphaiodoacrylate; alkyl alpha-cyanoacrylates, e.g. methyl alpha-cyanoacrylate and ethyl alpha-cyanoacrylate; maleates, e.g. monomethyl maleate, monoethyl maleate, dimethyl maleate and diethyl maleate; fumarates, e.g. monomethyl fumarate, monoethyl fumarate, dimethyl fumarate and diethyl fumarate; diethyl glutaconate; mono-olefinically unsaturated organic nitriles including, for example fumaronitrile, acrylonitrile, methacrylonitrile, ethacrylonitrile, 1,1-dicyanopropene-1, 3-octenenitrile, crotonitrile and oleonitrile; monoolefinically unsaturated carboxylic acids and anhydrides including, for example, acrylic acid, methacrylic acid, crotonic acid, 3-butenoic acid, cinnamic acid, maleic, fumaric and itaconic acids and maleic anhydride. Amides of these acids, such as acrylamide, are also useful. Vinyl alkyl ethers and vinyl ethers, e.g. vinyl methyl ether, vinyl ethyl ether, vinyl propyl ether, vinyl n-butyl ether, vinyl isobutyl ether, vinyl 2-ethylhexyl ether, vinyl 2-chloroethyl ether, vinyl propyl ether, vinyl n-butyl ether, vinyl isobutyl ether, vinyl 2ethylhexyl.ether, vinyl 2-chloroethyl ether and vinyl cetyl ether and vinyl sulfides, e.g. vinyl betachloroethyl sulfide and vinyl beta-ethoxyethyl sulfide can also be included as can diolefinically unsaturated hydrocarbons containing two olefinic groups in conjugated relation and the halogen derivatives thereof, e.g. butadiene1, 3; 2-methylbutadiene-1,3, 2,3 dimethylbutadiene-1,3; 2chloro-butadiene-1,3; 2,3dichlorobutadiene-1,3, and 2bromo-butadiene- 1,3.

Specific monomer compositions for forming copolymers are illustrated by vinyl chloride and vinylidene chloride and/or maleic or fumaric acid esters, vinyl chloride and vinylidene chloride and/or acrylate or methacrylate esters, vinyl chloride, vinylidene chloride and vinyl alkyl ether. These are given as illsutrative of the numerous combinations of monomers possible for the formation of copolymers. The present inven- tion is intended to cover all such combinations which fall within the scope of the present invention. While these combinations are intended to be included within the scope of the present invention, it is preferred that the polymer be formed from pure vinyl or vinylidene halide monomer and most preferably pure vinyl chloride.

When a comonomer is used it preferably should polymerize at the same or a faster rate in a theoretical bulk polymerization process as compared to said vinyl or vinylidene halide monomer. Up to 50% of a comonomer can be used. Examples of comonomers particularly useful in the polymerization process of the invention are methyl acrylate, ethyl hexyl acrylate, 2-hydroxyethyl acrylate, acrylic acid, stearyl methacrylate, methacrylic acid, methyl methacrylate and butylacrylate.

A free radical bulk polymerization can take place in accordance with the process of the invention at temperatures between 0 and 90"C. The polymerization reaction is conducted in the presence of a free radical initiator. Useful free-radical initiators are organic or inorganic peroxides, persulfates, ozonides, hydroperoxides, peracids and percarbonates, azo compounds, diazonium salts, diacotates, peroxysulfonates, trialkyl boraneoxygen systems, and amine oxides.

Azobisisobutyronitrile is particularly useful in the present invention. The initiator is used in concentrations ranging from 0.01 to 1.0% by weight based on the total weight of the monomers. For use in mass polymerization, the initiators which are soluble in the organic phase, such as benzoyl peroxide, diacetyl peroxide, azobisiso -butyronitrile, diisopropyl peroxydicarbonate, azobis (alphamethyl -gamma-carboxybutyronitrile), caparylyl peroxide, lauroyl peroxide, azobisisobutyramidine hydrochloride, t-butyl peroxupivalalate, 2,4dichlorobenzoyl peroxide, azobis (alpha, gamma-dimethylvaleronitrile), and 2,2' a azobis (2,4-dimethyl valeronitrile) are generally used, Preferably, the initiator which is used is chosen from the group of initiators known in the prior art as the "hot catalysts" or those which have a high degree of freeradical initiating activity. Initiators with a lower degree of activity are less desirable in that they require longer polymerization times. Also, long polymerization times may cause preliminary product degradation evidenced by color problems, e.g. pinking.

Since the activity of peroxy initiator compounds can be diminished by the presence of organic mercaptan and mercaptide salt functional groups it is preferred to employ a non-peroxy initiator, e.g. an azo initiator of the aforementioned type, when carrying out the polymerization of the invention in the presence of additives containing such functional groups.

In the liquid phase bulk polymerization method of the invention, all other conditions and measures are those conventionally employed in the previously known processes for bulk polymerization of vinyl chloride comprising a two-stage polymerization as disclosed in British Patent 1,047,489 and U.S.

Patent 3,522,227. In an integrated polymerization process of the invention with a twostage bulk polymerization process for vinyl or vinylidene halide, the reaction is conducted in a first stage reactor with means chosen to agitate the monomer or monomers of a type capable of providing high shear and commonly referred to as a "radical turbine type" agitator. At the start of the first stage reaction, the vessel is charged with a monomer composition to which a catalyst has been added. Any polymerization initiator generally used in bulk polymerization methods, that is those hereinabove described, can be used to an extent which is usual for bulk polymerization processes. After addition of the monomer to the first stage reactor, a small amount of monomer is vented in the process of removing the air from the first stage reactor vessel. The speed of the turbine-type agitator generally lies between 500 and 2,000 revolutions per minute or a tip speed of 2 to 7 meters per second in the first stage reactor. A tip speed of 0.5 to 2 meters per second is used in the second stage reactor. These figures should not be regarded as limiting values. As soon as a conversion of at least 3 to 15 percent of the monomer composition has been obtained in the first stage reactor, the contents of the vessel are transferred to a second stage polymerization vessel equipped to provide slow speed, low shear agitation so as to ensure proper temperature control of the reaction medium.

In order to further illustrate this invention but without being limited thereto, the following Examples are given. In this specification and claims, all parts and percentages are by weight and all temperatures are in degrees centigrade unless otherwise specified.

EXAMPLE I (Comparative Example) A vinyl chloride homopolymer is prepared in a two-stage bulk polymerization process by adding to a one-liter stainless steel reactor 0.10 milliliter of acetyl cyclohexane sulfonyl peroxide initiator (29% in dimethyl phthalate) and 0.10 gram of 2,2'-azobis-2, 4-dimethyl valeronitrile initiator. The reactor is alternately pressurized with nitrogen and placed under vacuum and subsequently 500 grams of vinyl chloride are introduced, following which 50 grams of vinyl chloride are vented from the reactor to remove entrapped air. The reaction is run for 20 minutes at 700C. and then the contents of the first stage reactor are transferred under pressure to two-liter glass reactor containing 300 grams of vinyl chloride, 50 grams of which are vented from the reactor, and 0.6 gram of the foregoing azobis dimethyl valeronitrile.

The polymerization is continued in the second stage for 6 hours at 650C. The polymer is obtained in a yield of 522 grams or about 74% (based on monomer reactant employed) after separating the unreacted monomer by venting the monomer from the vessel.

EXAMPLE 2 A vinyl chloride homopolymer is prepared in a two-stage bulk polymerization process by adding to a one-liter stainless steel reactor 0.10 milliliters of acetyl cyclohexane sulfonyl peroxide (29% in demethyl phthalate), 0.1 gram of 2,2'-azobis-2,4 -dimethyl valeronitrile and, as stabilizer and lubricant, a mixture of 4.1 grams of calcium stearate (corresponding to about 1.04% based on the weight of the polymer) and 0.4 gram of zinc stearate (corresponding to about 0.1% based on the polymer).

The reactor is alternately pressurized with nitrogen and placed under vacuum and subsequently 500 grams of vinyl chloride are introduced, following which 50 grams of vinyl chloride are vented from the reactor to remove entrapped air. The reaction is run for 20 minutes at 70"C and then the contents of the first stage reactor are transferred under pressure to a two-liter glass reactor containing 250 grams of vinyl chloride, 50 grams of which are vented from the reactor, 0.8 grams of the azobis dimethyl valeronitrile, 50 grams (corresponding to 12.7% based on the polymer) of a proprietary acrylic impact modifier (Acryloid K M 322B of Rohm & Haas Co.), 10 grams (corresponding to 2.53% based on the polymer) of an epoxidized soy bean oil stabilizer and plasticizer (G-62 of Rohm & Haas Co.), 4 grams (corresponding to about 1% based on the polymer of a tris(nonyl)phenyl phosphite stabilizer (M and T 187 of Metal and Thermet- Corp.) and 10 grams (corresponding to 2.53% based on the polymer) of a ethyl acrylate-methyl methacrylate copolymer processing aid containing about 13% ethyl acrylate monomer residues and about 87% methyl methacrylate monomer residues (Acryloid K-120N of Rohm & Haas Co.) The polymerization is continued in the second stage for about 6 hours at 65"C. After separation of the polymer product from the unreacted monomer by venting the latter from the reaction vessel the product containing the stabilizer, lubricant, plasticizer impact modifier, and processing aid additives as listed above is obtained in a yield of 473 grams corresponding to about 394 grams of polyvinyl chloride (i.e. computed as homopolymer without the additives of the invention) or about 61 % (based on the monomer reactant employed).

Comparison of this yield with the yield of Example 1 (especially with consideration of the lower propertion of vinyl chloride reactant employed in Example 2 compared to Example 1) illustrates that there is no substantial loss in polymer yield when the additives are incorporated into the polymer during its preparation by bulk liquid phase polymerization.

The polymer product when processed under conventional elevated temperature processing conditions in conventional polyvinyl chloride processing equipment exhibits excellent homogeniety, stability and processability characteristics.

EXAMPLE 3 The procedure of Example 2 is repeated substantially as described except that addition of the acrylic impact modifier is omitted.

An excellent yield of polymer product, substantially similar in homogeneity, stability and processability to that of Example 2 is obtained.

EXAMPLE 4 The procedure of Example 2 is repeated substantially as described except that addition of the acrylic impact modifier and the epoxidized soy bean oil stabilizer and plasticizer is omitted. An excellent yield of polymer product, substantially similar in homogeniety, stability and processability to that of Example 2, is obtained.

EXAMPLE 5 The procedure of Example 1 is repeated substantially as described except that the contents of the first reaction stage are transferred to the second stage reaction vessel containing 250 grams of vinyl chloride, 50 grams of which are vented from the reactor, 0.8 grams of the azobis-dimethyl valeronitrile initiator compound, 10 grams (corresponding to 2.44% based on the polymer) of a proprietary stabilizer and lubricant agent which comprises a mixture of cadmium and barium fatty carboxylic acid soaps and an antioxidant (Ferro 1825 of Ferro Corp.), 50 grams (corresponding to 12.2% based on the polymer) of the acrylic impact modifier of Example 2, 10 grams (corresponding to 2.44% of the polymer) of the processing aid of Example 2 and 5 grams (corresponding to 1.22% based on the polymer) of the oxidized soy bean oil stabilizer and plasticizer of Example 2. The polymerization is continued in the second stage for 6 hours. After separation of the polymer product from unreacted monomer, the product is obtained in a yield of 485 grams of polyvinyl chloride resin, (i.e.

computed as homopolymer without the additives of the invention) or about 63% (based on the monomer reactant employed).

The product is similar to that of Example 2 in its homogeniety, stability and processability.

WHAT WE CLAIM IS: 1. A liquid phase bulk polymerization process for producing a polymer of a vinyl or vinylidene halide, wherein the polymerization reaction is carried out in the presence of additives comprising a heat and/or light stabilizer for the polymer, an organic lubricant for the polymer, and an organic processing aid for the polymer, wherein each additive is present in the polymerization reaction in an amount sufficient to provide an effective concentration of 0.01 to 5 weight percent of each additive based on the polymer.

2. A process according to claim 1 wherein the stabilizer is an organic compound employed at a concentration of 0.1 to 3 weight percent and the concentrations of lubricant and processing aid are 0.1 to 1 weight percent and 1 to 3 weight percent, respectively the concentrations being based on the weight of the polymer.

3. A process according to claim 1 or 2 wherein the organic stabilizer is at least one carboxylic acid salt of a metal selected from calcium, magnesium, strontium, barium, manganese, cadmium, zinc, tin (stannous and stannic) and lead.

4. A process according to claim 3 wherein the metal carboxylate salt is a substantially water-insoluble salt of a carboxylic acid of 6 to 18 carbon atoms.

5. A process according to claim 4 wherein the organic stabilizer is a mixture of calcium and zinc stearates.

6. A process according to any one of the preceding claims wherein the organic processing aid is an ethyl acrylate-methyl methacry

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. polymer) of a proprietary acrylic impact modifier (Acryloid K M 322B of Rohm & Haas Co.), 10 grams (corresponding to 2.53% based on the polymer) of an epoxidized soy bean oil stabilizer and plasticizer (G-62 of Rohm & Haas Co.), 4 grams (corresponding to about 1% based on the polymer of a tris(nonyl)phenyl phosphite stabilizer (M and T 187 of Metal and Thermet- Corp.) and 10 grams (corresponding to 2.53% based on the polymer) of a ethyl acrylate-methyl methacrylate copolymer processing aid containing about 13% ethyl acrylate monomer residues and about 87% methyl methacrylate monomer residues (Acryloid K-120N of Rohm & Haas Co.) The polymerization is continued in the second stage for about 6 hours at 65"C. After separation of the polymer product from the unreacted monomer by venting the latter from the reaction vessel the product containing the stabilizer, lubricant, plasticizer impact modifier, and processing aid additives as listed above is obtained in a yield of 473 grams corresponding to about 394 grams of polyvinyl chloride (i.e. computed as homopolymer without the additives of the invention) or about 61 % (based on the monomer reactant employed). Comparison of this yield with the yield of Example 1 (especially with consideration of the lower propertion of vinyl chloride reactant employed in Example 2 compared to Example 1) illustrates that there is no substantial loss in polymer yield when the additives are incorporated into the polymer during its preparation by bulk liquid phase polymerization. The polymer product when processed under conventional elevated temperature processing conditions in conventional polyvinyl chloride processing equipment exhibits excellent homogeniety, stability and processability characteristics. EXAMPLE 3 The procedure of Example 2 is repeated substantially as described except that addition of the acrylic impact modifier is omitted. An excellent yield of polymer product, substantially similar in homogeneity, stability and processability to that of Example 2 is obtained. EXAMPLE 4 The procedure of Example 2 is repeated substantially as described except that addition of the acrylic impact modifier and the epoxidized soy bean oil stabilizer and plasticizer is omitted. An excellent yield of polymer product, substantially similar in homogeniety, stability and processability to that of Example 2, is obtained. EXAMPLE 5 The procedure of Example 1 is repeated substantially as described except that the contents of the first reaction stage are transferred to the second stage reaction vessel containing 250 grams of vinyl chloride, 50 grams of which are vented from the reactor, 0.8 grams of the azobis-dimethyl valeronitrile initiator compound, 10 grams (corresponding to 2.44% based on the polymer) of a proprietary stabilizer and lubricant agent which comprises a mixture of cadmium and barium fatty carboxylic acid soaps and an antioxidant (Ferro 1825 of Ferro Corp.), 50 grams (corresponding to 12.2% based on the polymer) of the acrylic impact modifier of Example 2, 10 grams (corresponding to 2.44% of the polymer) of the processing aid of Example 2 and 5 grams (corresponding to 1.22% based on the polymer) of the oxidized soy bean oil stabilizer and plasticizer of Example 2. The polymerization is continued in the second stage for 6 hours. After separation of the polymer product from unreacted monomer, the product is obtained in a yield of 485 grams of polyvinyl chloride resin, (i.e. computed as homopolymer without the additives of the invention) or about 63% (based on the monomer reactant employed). The product is similar to that of Example 2 in its homogeniety, stability and processability. WHAT WE CLAIM IS:

1. A liquid phase bulk polymerization process for producing a polymer of a vinyl or vinylidene halide, wherein the polymerization reaction is carried out in the presence of additives comprising a heat and/or light stabilizer for the polymer, an organic lubricant for the polymer, and an organic processing aid for the polymer, wherein each additive is present in the polymerization reaction in an amount sufficient to provide an effective concentration of 0.01 to 5 weight percent of each additive based on the polymer.

late copolymer and there is also present as stabilizer an epoxide stabilizer, an organic phosphite stabilizer or a mixture thereof.

7. A process according to claim 6 wherein the epoxide stabilizer is an epoxidized natural oil and the phosphite stabilizer is a tris-alkyl phenyl-phosphite of 8 to 12 carbons in the alkyl group.

8. A process according to claim 7 wherein the epoxide stabilizer is epoxidized soy bean oil or epoxidized linseed oil.

9. A process according to claim 7 wherein the epoxide stabilizer is epoxidized soy bean oil and the phosphite ester stabilizer is tris(nonylphenyl) phosphite.

10. A process according to any one of the preceding claims wherein the bulk polymerization is carried out in two stages, a first stage wherein the reaction mixture is subjected to high speed agitation until 3% to 15% by weight of polymerizable monomer material in the reaction mixture has been converted to polymer and a second stage wherein the resultant reaction mixture is subjected to low speed agitation until 30% to 85% of the polymerizable monomer material has been converted to polymer.

11. A process according to claim 10 wherein the processing aid contains about 13 weight percent ethyl acrylate monomer residues and about 87 weight percent methyl methacrylate monomer residues, a carboxylate salt stabilizer and lubricant are present in the first stage of polymerization and the processing aid, phosphite ester stabilizer and epoxide stabilizer are added in the second stage of polymerization.

12. A process according to any one of the preceding claims wherein the additive mixture contains a small effective concentration of an organic impact modifier for the polymer.

13. A process according to any one of the preceding claims wherein the additive mixture contains a small effective concentration of an organic plasticizer for polyvinyl halide.

14. A process according to any one of the preceding claims wherein the vinyl or vinylidene halide is vinyl chloride which is either homopolymerized or copolymerized with up to 50%by weight of at least one ethylenically unsaturated monomer copolymerizable therewith.

15. A process according to claim 1 substantially as described in any one of Examples 2 to 5.

16. A vinyl or vinylidene halide polymer when produced by a process as claimed in any one of the preceding claims.