| 摘要 |
A process for the production of polyurethane plastics comprises reacting at least one organic compound having at least two reactive hydrogen atoms, a molecular weight of at least 1000 and a hydroxyl number not exceeding 112, with an organic dihydroxy cross-linking agent having a molecular weight of less than 1000 and with an organic polyisocyanate in an amount insufficient to react with all the free OH groups present, and curing the polyurethane so produced in the presence of an organic peroxide. The polyurethane to be cured may be obtained by reacting the compound of M.Wt. to above 1000 with excess polyisocyanate and reacting the product with excess diol; or by adding a reaction product of the diol and the polyisocyanate with the compound of M.Wt. above 1000; or by adding the polyisocyanate to the mixed hydroxycompounds. Polyesters, polyalkylene ethers, polythioethers and polyacetals are suitable compounds of molecular weight above 1000. Toluene 2,4- or 2,6-, 4,41-diphenylmethane, m- or p-phenylene, diphenyl, azobenzene-4,41-diphenylsulphone-4,41, diphenylsulphone-4,41, 1-isopropylbenzene-3,5-, dicyclohexylmethane-4,41-tetramethylene and hexamethylene diisocyanates and bis-(3-isocyanatobenzoic acid)-diethylene glycol ester are specified polyisocyanates. Suitable crosslinking agents are 1,4-butendiol; butenedihydroxy ethyl glycol butynediol; butyne dihydroxy ethyl glycol; esters which contain hydroxyl groups (such as dihydroxyethyl maleate, beta-dihydroxyethyl dihydromuconate and dihydroxyethyl fumarate); polyesters (which may be unsaturated) containing hydroxyl groups; beta-hydroxyethyl amides of fumaric or dihydromuconic acids; dicycloheptene dicarboxylic acid glycol ester; 1,3- or 1,4 - butanediol; hydroquinone - di - (b - hydroxy - ethyl) - ether, quinitol; 4,41 - dihydroxy - dicyclohexyl - dimethyl - methane; 4,41 - dihydroxy - dicyclohexylmethane. Dicumyl, benzoyl, methylethyl ketone, diacetyl and succinyl peroxides, tertiary butyl perbenzoate; 2,21 - bis - (tertiary butyl peroxy)butane; and cyclohexanone and cumene hydroperoxides are suitable organic peroxides. The peroxide may be added in admixture with calcium carbonate or dibutyl phthalate. Carbon black, silicic acid aerogel and lubricants (e.g. stearic acid) can be incorporated simultaneously.
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