GB808635A - Improvements in or relating to elastomeric polymers and their production - Google Patents

Abstract

The invention comprises polymeric polyurethanes consisting essentially of substantially equimolecular amounts of (1) radicals obtainable by removing the terminal chlorine atoms from bis-chloroformates alternating with (2) radicals obtainable by removing one hydrogen atom from each of the nitrogens of a diamine, said diamine having at least one primary amine group, at least 60 per cent of the total weight of the polymer being the polymeric radicals obtainable by removing the terminal chlorine atoms from bis-chloroformates having molecular weights of at least 875 and consisting of polyalkylene-ether bis-chloroformates, polyalkyleneether - thioether bis - chloroformates, polyalkylenearylene-ether bis-chloroformates, polyurethane bis-chloroformates or polyaliphatic hydrocarbon bis-chloroformates (i.e. bis-chloroformates in which the chain carrying the chloroformate groups is obtained by polymerization of an unsaturated aliphatic hydrocarbon); the polymeric polyurethanes having attached to at least one of the radicals obtained from the diamine a side chain containing a primary hydroxyl group, the said chain occurring at least once for every 8000 molecular weight units of the polymeric polyurethanes. Such polymers are obtained by reaction of the appropriate chloroformate and the hydroxyl-containing diamine. There may be used in addition a further diamine or a bis-chloroformate of a low molecular weight non-polymeric glycol (i.e. M.Wt. below about 200). The preferred polyalkyleneether glycol is polytetramethylene-ether glycol. Others specified are polyethylene-ether, polypropylene - ether 1,2 - polydimethylethyleneether and polydecamethylene-ether glycols. Suitable polyurethane glycol bis-chloroformates are prepared by reacting a molar excess of a polymeric glycol, such as a polyalkylene-ether glycol, with an organic diisocyanate and treating the product with phosgene. Specified diisocyanates are toluene, m-phenylene, 4-chloro-1,3-phenylene, 4,41-biphenylene, 1,5-naphthylene, 1,4-tetramethylene, 1,6-hexamethylene, 1,10-decamethylene, 1,4-cyclohexylene, and 1,5-tetrahydronaphthylene diisocyanates and 4,41-methylene - bis - (cyclohexyl isocyanate). Suitable diamines are N-b -aminoethylethanolamine, 1,5-diamino-naphthalene, m-tolylene diamine, hexamethylene diamine, 1,4-cyclohexyl diamine, ethylene diamine and N-(b -hydroxyethyl) - p - phenylene diamine. Suitable low molecular weight glycols (the bis-chloroformates of which are optionally also employed), are ethylene glycol, 1,3-propylene glycol, 1,4-butanediol, 1,5-pentanediol, and p-phenylene dicarbinol. The hydroxyl groups in the polymeric polyurethane act as curing sites, the diisocyanates referred to above being suitable curing agents, being milled in before moulding under heat and pressure. In examples: (1) polytetramethylene-ether glycol of molecular weight 955 (in excess) is heated with toluene-2,4-diisocyanate and the polyurethane glycol obtained is reacted with phosgene. The resulting polyurethane bis-chloroformate is reacted with N-b -aminoethylethanolamine to give a polymer which is compounded with channel black and 3,31-dimethyl-4,41-biphenyl diisocyanate and cured under heat and pressure; (2) a polytetramethylene-ether bis-chloroformate (prepared by reacting phosgene with a polytetramethylene-ether glycol of molecular weight 3010) is reacted with a mixture of 1,5-diaminonaphthalene and aminoethylethanolamine. The resulting polymer is compounded with carbon black and 3,31-dimethyl-4,41-biphenyl diisocyanate and cured. The products can be used in tyres, inner tubes, belts, hose and tubing, wire and cable jackets, footwear, sponges and coated fabrics. Other compounding agents specified are clay, silica, esterified silica particles, talc, zinc and magnesium oxides, calcium and magnesium carbonates, titanium dioxide, plasticisers and inorganic and organic colouring agents.