Patent GB-729028-A (GB)
Title: Improvements in or relating to xylylene acrylates and methacrylates
IPC: C08F20/18
Filed: 1953-11-26
Abstract: Esters having the formula <FORM:0729028/IV (a)/1> in which R is a hydrogen atom or a methyl group (see Group IV (b)) polymerize by addition polymerization, and also copolymerize with other materials containing at least one vinylidene group, CH2=C<.  Since the esters contain two vinylidene groups they are excellent cross-linking agents and on polymerization give insoluble, cross-linked products. Compounds which copolymerize with these esters are for example, vinyl chloride; acrylonitrile; vinylidene chloride and cyanide; styrene, divinylbenzene, vinyltoluene, vinylnaphththalenes and vinylanthracenes; vinyl acetate and propionate; diallyl phthalate and maleate; esters of acrylic and methacrylic acids with monohydric alcohols including methanol, ethanol, butanols, capryl alcohol, benzyl alcohol, lauryl alcohol and octadecyl alcohols.  The polymerizations may be carried out in bulk, in solution, in suspension or in aqueous emulsion.  Polymerization or copolymerization is accelerated by heat, ultra-violet light and free radical catalysts such as benzoyl peroxide, acetyl peroxide, lauroyl peroxide, succinyl peroxide, tert.-butyl hydroperoxide, di-tert.-butyl peroxide, tert.-butyl perbenzoate, stearoyl peroxide, ascaridole, cumene hydroperoxide, caprylyl peroxide, azoisobutyronitrile and methyl azoisobutyrate.  In an example, copolymers prepared from the esters and a wide variety of compounds containing at least one CH2=C< group, were found to be insoluble in solvents which dissolved polystyrene or polymethyl methacrylate, which indicated extensive cross-linking.ALSO:New esters having the general formula <FORM:0729028/IV (b)/1> in which R is a hydrogen atom or a methyl group, are prepared by reacting an alkali metal salt of acrylic or methacrylic acid, with the corresponding xylylene halide, in the presence of an organic solvent for the xylylene halide, and of a basic catalyst at a temperature of 70 DEG  to 130 DEG  C. Generally the process is carried out using a sodium or potassium salt of the acrylic or methacrylic acid, p-xylylene chloride and a temperature of 80-110 DEG  C.  A slight excess of the alkali metal salt is used, and mixtures of the xylylene halides may be used as well as the individual isomers but the p-xylylene halide is preferred since it gives a solid ester at room temperature.  Suitable solvents are dioxane, benzene, toluene, xylene, methanol, ethanol, propanol, butanol, acetone and methyl ethyl ketone.  The basic catalyst is preferably soluble in the reaction mixture, and alkali metal alcoholates are preferred to alkali metal hydroxides or the alkali metals.  The most satisfactory catalysts are the quaternary ammonium halides or hydroxides, e.g. trimethylbenzylammonium chloride or hydroxide, dimethylethylphenylammonium chloride or hydroxide and triethylbenzylammonium bromide or hydroxide.  Since the reaction products polymerize by addition polymerization, a suitable polymerization inhibitor such as di-beta-naphthol or hydroquinone is added.  These xylylene esters also copolymerize with other materials which contain at least one vinylidene group, CH2 = C<, and since the esters contain two vinylidene groups, they are excellent cross-linking agents and give insoluble cross-linked products (see Group IV (a)).  In examples, p-xylylene methacrylate, p-xylylene acrylate and the compounds obtained when a commercial mixture of the xylylene chloride isomers is used, are prepared.  The formation of copolymers and their insolubility is also described (see Group IV (a)).