Patent GB-410132-A (GB)
Title: Improvements in the manufacture and production of polymerisation products
IPC: C08F14/06
Filed: 1932-11-07
Abstract: Coating-compositions.--Aqueous dispersions of polyvinyl halides (chloride, bromide or iodide), obtained by polymerizing aqueous emulsions of vinyl halides, alone or in admixture with one another or with monomeric vinyl esters of carboxylic acids containing up to four carbon atoms in the molecule, e.g. vinyl acetate, butyrate or chloracetate, if desired with the addition of softening agents, such as phosphoric esters, e.g. tri-n-butyl or triphenyl phosphate, phthalic esters, e.g. di-n-propyl or n-butyl phthalate or di-(ethylene glycol monomethyl ether) phthalate, camphor or ethyl or propyl ethers of glycerine, may be used directly for varnishing or coating fabrics, leather or wood or metal, by spraying, brushing or dipping, any desired additions of softening agents, fillers, e.g. cork meal, soot or bentonite, or pigments, e.g. lakes from Lithol Red, Indanthrene Blue, zinc oxide or colcothar, being added, if desired, in an emulsified or dispersed form.  The polymerization products obtained by coagulating the dispersions may be used alone as substitutes for or additions to organic film forming substances of high molecular weight, such as cellulose esters or ethers, e.g. cellulose nitrate or benzyl cellulose, or to rubber or rubber-like polymerization products of olefines, e.g. butadiene, for the preparation of coatings, lacquers or varnishes.  Emulsions, making.--The emulsions of the vinyl halides are prepared, in the case of vinyl chloride, which is a gas, essentially, and in the case of vinyl bromide, preferably, in a closed vessel, e.g. a stirring autoclave, under pressure. Specifications 328,963, 341,053, 343,899, 366,916, and 367,585 are referred to.ALSO:Polymerization products are manufactured by subjecting an aqueous emulsion of a vinyl halide (chloride, bromide or iodide) to polymerization while using pressures which are of the range of the vapour tension of the reactants at the temperature of working and which are not higher than about 30 atmospheres.  The aqueous emulsions of the vinyl halides may be prepared in the usual manner for producing emulsions, e.g. with the aid of turbo mixers or homogenizing machines or by stirring the halides into water to which dispersing or emulsifying agents are preferably added.  In the case of vinyl chloride it is necessary and in the case of vinyl bromide preferable to carry out the emulsification in a closed vessel, e.g. a stirring autoclave, the same vessel being preferably also employed for the polymerization. The polymerization may be carried out by heating, e.g. to about 35--80 DEG  C., preferably to about 40--55 DEG  C., or by irradiation with chemically active rays, e.g. sunlight or light from a mercury vapour lamp, or a combination of these means, if desired in the presence of polymerization accelerators such as active oxygen in the form of inorganic peroxides, e.g. ozone or hydrogen peroxide, lithium, potassium or sodium perborates, persulphuric acid or organic peroxides, e.g. acetyl or benzoyl peroxide, peracetic acid, perbenzoic acid or acetone peroxide.  When working on a large scale it is preferable to introduce the aqueous emulsion into the reaction vessel at the rate at which the polymerization proceeds.  It is also possible to introduce the vinyl halide, while stirring, into the aqueous liquid in the reaction vessel at the rate at which the polymerization proceeds.  The emulsion is preferably continuously kept in motion during the polymerization by stirring, shaking or pumping it in circulation.  The dispersing and emulsifying agents may be chosen from all the known dispersing, emulsifying, wetting, soaping or washing agents, e.g. alkali metal, ammonium and amine salts of fatty acids containing at least 12 carbon atoms, e.g. sodium, potassium or ammonium palmitate or stearate, Marseilles soap, or mono-, di- or triethanolamine salts of lauric or palmitic acid, salts of true sulphonic acids or of acid sulphuric esters of organic compounds containing at least 8 carbon atoms, e.g. those of alkylnaphthalenesulphonic acids, e.g. mono- and di-(normal or iso)-butylnaphthalenesulphonic acids, mono- and di-(normal or iso) - propylnaphthalene - sulphonic acids, of true sulphonic acids from oleic or palmitic acids, or salts of acid sulphuric esters of fatty alcohols containing at least 12 carbon-atoms, e.g. dodecyl alcohol, tetradecyl alcohol or cetyl alcohol, or salts of true sulphonic acids of such alcohols, e.g. the sodium salt of hydroxyoctodecanesulphonic acid (obtainable by acting with acetic anhydride and sulphuric acid monohydrate on octodecylene), also the sodium salts of N-oleic-N-alkyltaurides, of N-oleic tauride, of the fatty esters of hydroxyalkylsulphonic acids, e.g. the sodium salt of the oleic ester of hydroxyethanesulphonic acid, and the sodium salts of fatty acid esters of hydroxycycloalkyl or -arylsulphonic acids.  There may be added to the emulsions small amounts, e.g. 0.5--3 per cent, by weight of the aqueous liquid, of acid reacting agents, e.g. acetic or boric acid, or mixtures thereof with buffer salts, e.g. lithium acetate or borate, or of primary sodium phosphate alone or, preferably, of sodium pyrophosphate.  Preferably the pH value is adjusted to between about 1.5 and 5, the best results being obtained at between about pH=2.5 and pH=3.  It is possible to combine the adjustment of the pH value with the addition of the polymerization catalysts, e.g. by employing a solution of the catalysts in glacial acetic acid. The vinyl halides may be polymerized alone or in admixture with one another or with monomeric vinyl esters of carboxylic acids containing up to four carbon atoms in the molecule, e.g. vinyl acetate, vinyl butyrate (obtainable by the action of acetylene on butyric acid in the presence of mercury compounds), or vinyl chloracetate.  The amount of such vinyl esters may be as small or as large as desired, e.g. about 10--30 or 33 per cent of the weight of vinyl chloride, the best products being obtained from mixtures of about 80 parts of vinyl chloride with about 20 parts of vinyl carboxylate.  It is advantageous to add organic softening agents, such as phosphoric esters, e.g. tri-n-butyl phosphate (obtainable by mixing butyl alcohol with phosphorus oxychloride at a temperature not exceeding 15 DEG  C., warming in vacuo to 40 DEG  C., washing and fractionating), or triphenyl phosphate, phthalic esters, e.g. di-n-propyl or n-butyl phthalate or di-(ethylene glycol monomethyl ether) phthalate (obtainable by boiling 2 molecular proportions of ethylene glycol monomethyl ether with one of phthalic anhydride in the presence of sulphuric acid and benzene), camphor or ethyl or propyl ethers of glycerine, to the vinyl halides or mixtures thereof with vinyl carboxylates, before or during polymerization, or to incorporate them with the finished polymerization products.  The products may be separated from the aqueous liquids by coagulation with inorganic non-oxidizing acids, e.g. sulphuric, phosphoric or hydrochloric acids, with salts such as sodium chloride, magnesium chloride, alum or aluminium phosphate or sulphate, or with low molecular aliphatic monohydric alcohols, e.g. methyl or ethyl alcohol, aluminium salts being preferably employed, or by freezing out, e.g. by cooling the aqueous dispersions to below 0 DEG  C., e.g. to - 5 DEG  to - 8 DEG C., or by cataphoresis.  The aqueous dispersions may also serve directly for varnishing, impregnating or coating fabrics, leather or wood or metal, by spraying, brushing or dipping, any desired additions of softening agents, fillers, e.g. cork meal, soot or bentonite, or pigments, e.g. lakes from Lithol Red, Indanthrene Blue, zinc oxide or colcothar, being added, if desired, in an emulsified or dispersed form.  The polymerization products may be used alone as substitutes for or additions to organic film forming substances of high molecular weight, such as cellulose esters or ethers, e.g. cellulose nitrate or benzyl cellulose, or to rubber or rubber-like polymerization products of olefines, e.g. butadiene, for the preparation of threads, films, coatings, lacquers, varnishes or pressed die or injection moulded articles, electric insulating material and celluloidlike articles.  The polymerization is preferably carried out in the absence of iron, e.g. in enamelled vessels, or alternatively iron may be removed from the polymerization product, e.g. by washing with aqueous oxalic or tartaric acid.  In examples: (1) vinyl chloride and a solution of peracetic acid in glacial acetic acid are allowed to flow from a reservoir under pressure, while stirring, into a closed vessel containing an aqueous solution of N-methyl-N-oleic tauride sodium salt and lithium borate at 50 DEG  C. and the resulting dispersion is coagulated by means of dilute sulphuric acid; (2) vinylchloride and diethyl mono-(ethylene glycol n-butyl ether) phosphate (obtainable by the process described in Specification 328,963, [Class 2 (iii)], from phosphorus oxychloride, ethyl alcohol and ethylene glycol n-butyl ether) are emulsified by means of a closed turbo mixer in water containing Turkey red oil, lithium borate and hydrogen peroxide, the emulsion is heated to 50 DEG  C. and the resulting dispersion is coagulated by means of dilute sulphuric acid; the product may be pressed into moulds; (3) vinyl chloride and vinyl acetate are emulsified in a closed vessel in water containing the sodium salt of hydroxyoctodecanesulphonic acid; a solution of peracetic acid in glacial acetic acid is added, the mixture is heated to 45 DEG  C. in an autoclave at a pressure up to 7 atmospheres and the resulting dispersion is treated with steam and then coagulated by pouring it into an aqueous solution of aluminium sulphate, the solution being rendered alkaline by means of sodium hydroxide and the product filtered and dried; it may be pressed into moulds or may be pressed at about 100 DEG  C., like cel