Patent GB-810221-A (GB)
Title: Stabilized polymerizable materials and process for preparation
IPC: C08K5/18
Filed: 1956-06-19
Abstract: A stabilized liquid material comprises at least one polymerizable material consisting of (a) unsaturated linear polyesters, or (b) ethylenically unsaturated monomers which contain at least one non-conjugated CH2=C< group and less than 2 per cent based on the weight of said polymerizable material, of N,N1-di-2-(1,4 -naphthoquinonyl) - p - phenylenediamine.  The stabilizer is preferably present in an amount of 0.005 per cent to about 1 per cent.  The unsaturated linear polyesters are inhibited from polymerizing by addition polymerization, especially when mixed with the above monomeric compounds.  The unsaturated polyesters are made by the esterification of an a ,b -unsaturated dicarboxylic acid, such as maleic or fumaric acids, with a dihydric alcohol, such as ethylene glycol, propylene glycol or 1,6 -hexanediol.  They can also contain one or more esterified dicarboxylic acids which are free of non-benzenoid unsaturation, such as adipic, sebacic or phthalic acids.  The stabilizer may be added in the form of a solution, preferably in ethanol.  The inhibiting effect of the stabilizer can be overcome by the addition of a dominant amount of a polymerization catalyst of the free-radical type, such as tert.-butyl hydroperoxide. In Example (1), 10,11-epoxy-undecyl methacrylate was polymerized in the presence of 0.5 per cent benzoyl peroxide at 60 DEG  C.  In Example (5), 4-pentenyl methacrylate was polymerized in the presence of 1 per cent benzoyl peroxide.ALSO:Polymerizable materials consisting of (a) unsaturated linear polyesters or (b) ethylenically unsaturated monomeric compounds which contain at least one non-conjugated group of the structure CH2=C< are stabilized by mixing therewith less than 2 per cent, based on the weight of said polymerizable material, of the compound N,N1-di-2-(1,4-naphthoquinonyl)-p-phenylenediamine. The stabilizer is effective in amounts from 0.005 to about 1 per cent.  The unsaturated linear polyesters are made by esterification of an a ,b -unsaturated dicarboxylic acid, such as maleic or fumaric acid, with a dihydric alcohol, such as ethylene glycol, propylene glycol or 1,6-hexanediol. They may also contain one or more esterified dicarboxylic acids which are free of non-benzenoid unsaturation such as adipic, sebacic or phthalic acids.  The ethylenically-unsaturated monomers are exemplified by acrylic and methacrylic acids, acrylamide, methacrylamide, acrylonitrile, methacrylonitrile, methacrylyl chloride, methyl methacrylate, ethyl acrylate, butyl acrylates, octyl methacrylates, glycidyl methacrylate, isopropylidene glyceryl methacrylate, 3,3,5 - trimethylcyclohexyl acrylate, styrene, vinyltoluene, ethylstyrene, vinylnaphthalene, vinylanthracene, divinylbenzene, trivinylbenzene, vinyl bromide, vinyl acetate, vinyl propionate, vinyl butyral, vinylidene chloride, N-vinyl-N,N1-ethyleneurea, diallyl phthalate, diallyl succinate and triallyl trimesate.  The stabilizer may be used to stabilize the polymerizable monomers under conditions of storage and transportation, during preparation and also during distillation of the monomers.  Thus the liquid monomer, such as methyl methacrylate, may be introduced continuously into the pot containing the stabilizer at about the same rate as the monomer is distilled therefrom.  The stabilizer may be added to the monomers in the form of a solution, preferably in ethanol, and may be separated from the monomers by distillation of the latter by adsorption on conventional adsorbents such as diatomaceous earth or clay, or by extraction with suitable solvents.  Its stabilizing effect can be overcome by the addition of a dominant amount of a polymerization catalyst of the free radical type, such as t-butyl hydroperoxide.  In examples: 1) a mixture of 10,11-epoxyundecyl methacrylate and 10-undecyl methacrylate is stabilized with N,N1-di-2-(1,4-naphthoquinonyl)-p-phenylene diamine and distilled to obtain the pure epoxy compound; (2) glycidyl methacrylate containing the above stabilizer is refluxed and distilled without polymerization; (3) methacrylyl chloride is prepared by refluxing a mixture of thionyl chloride and the stabilizer and slowly adding methacrylic acid, the product being distilled through a fractionating column; (4) N-vinyl-N,N1-ethyleneurea is prepared by mixing N-(b -chloroethyl)-N,N1-ethylene urea, anhydrous toluene, sodium methoxide and the stabilizer, heating and taking off a distillate as fresh toluene is added, filtering, stripping off toluene and distilling off the product at reduced pressure; (5) 4-pentenyl methacrylate is prepared by heating together methyl methacrylate, 4-penten-1-ol, p-toluenesulphonic acid and the above stabilizer and the product is purified by distillation; (6) 4-pentenyl methacrylate is prepared as in (5) but using sodium in methanol as catalyst; (7) 4,5-epoxypentenyl methacrylate is prepared by reacting 4-pentenyl methacrylate with peracetic acid in acetic acid with addition of sodium acetate in the presence of the above stabilizer, the product being extracted with benzene, washed and dried and fractionated in the presence of the stabilizer.