| 摘要 |
521,489. Polymerizable compositions methyl methacrylate. HAMBLIN, F. T., CODD, L. W., and IMPERIAL CHEMICAL INDUSTRIES, Ltd. Aug. 19, 1938, Nos. 24518/38 and 8477/40 (the second Provisional Specification being divided out of the first Provisional Specification). [Class 2 (iii)] A polymerizable composition comprises methyl methacrylate in admixture with a polymerization inhibitor in such proportions that it possesses substantial inhibitory properties at temperatures up to 40‹C., but possesses substantially no inhibitory properties at temperatures of 100‹C. or above. The inhibitors used may be volatile substances or substances which are decomposed at 100‹C., such as benzoic acid, acetamide, crotonic acid, ammonium carbonate or carbamate, ammonia, pyrrol, hexamine or aldehyde ammonia, but it is preferred to employ substances which are rendered ineffective by reaction with the methyl methacrylate, such as tannic acid, piperidine, resorcinol and hydroquinone. The proportions of these substances employed are such that at 100‹C. polymerization takes place in a time not substantially greater than four times that required for the polymerization of a similar composition containing no inhibitor. Examples are given showing the effect on the time of polymerization of varying proportions of tannic acid, piperidine, resorcinol and hydroquinone. |
