Preparation of foamed polyurethane elastomers from (a) a polyether, (b) dicyclohexylmethane diisocyanate or hexamethylene diisocyanate, (c) hydrogen peroxide, (d) water, and (e) a catalyst

摘要

A foamed polyurethane is made by (a) reacting a polyol containing terminal or substantially terminal hydroxyl groups with an aliphatic or alicyclic diisocyanate (e.g. dicyclohexylmethane diisocyanate), (b) mixing the reaction product with water, a source of hydrogen peroxide, a catalyst and, possibly, a foam stabilizer (e.g. a silicone) and (c) heating the mixture to effect foaming. The catalyst is triethylene diamine, an alkyl metallo-ester (e.g. dibutyl tin dilaurate), an alkoxy metallo-ester (e.g. dibutoxy tin dilaurate), or a tin soap (e.g. stannous octoate). The polyol may be a hydroxy-polyester, -polyesteramide or -polyether (e.g. polypropylene oxide or oxypropylated glycerol). The sulphur analogues of the isocyanates, ethers and polyols may be used. The hydrogen peroxide may be added as such or in the form of barium peroxide or urea hydrogen peroxide. An antioxidant, e.g. an alkylene bis dialkyl dithiocarbamate may be incorporated in the foamable composition. The resulting foam may be compressed between rollers to break any closed cells.