| 摘要 |
A process for preparing soft, resilient, low density polyurethane foam from an essentially hydroxyl-terminated polyester, a polyisocyanate and water comprises incorporating finely divided mica into the reaction mixture. 5 to 50 parts, preferably 15 to 30 parts, of mica to each 100 parts by weight of polyester may be used. It may be natural or synthetic and preferably has an average particle size of less than about 200 microns. The polyesters are preferably linear, although they may be derived from mixtures containing up to about 5 mol. per cent of trimethylol propane or 3.5 mol. per cent of pentaerythrital, based on the dicarboxylic acid. The molecular weight of the ester may be from about 500 to 5000, and preferably is between 1200 and 1800. Specified polyisocyanates are tolylene, ethylbenzene, isopropyl benzene, diethyl benzene and m-phenylene diisocyanates and p,p1-diisocyanato-diphenyl methane. As accelerators there may be added to the reaction mixture potassium hydroxide, organic bases such as tertiary amines and a soap such as potassium ricinoleate. In examples, tolylene diisocyanate is stirred into a heated mixture of hydroxyl terminated polyethylene adipate and mica, followed by water and aqueous potassium ricinoleate. The foamed product obtained is rinsed with water and heated at 100 DEG C. The properties are given of foams prepared using mica in different amounts, particle size and type. A polyester from diethylene glycol and adipic acid can be employed similarly. |
