GB963340A - Improvements in or relating to the production of polyurethane plastics - Google Patents

Abstract

A process for the production of cellular or noncellular polyurethane plastics comprises reacting an organic polyisocyanate with a polyester containing free hydroxyl groups which has been obtained by reacting a tertiary organic phosphite with a partial ester of an unsaturated carboxylic acid and a polyhydric alcohol. In a preferred embodiment the polyesters are produced by reacting a polyhydric alcohol with an a ,b -unsaturated dicarboxylic acid (e.g. 4 mols. of a trihydric alcohol to 3 mols. of a ,b -unsaturated dicarboxylic acid). The partial ester is then reacted with 3 mols. of the phosphite, the organic radicals of the phosphite being split off by transesterification. Suitable acids are maleic, methyl-maleic, chloro-maleic, methylene-succinic, fumaric, glutaconic, a - or b -hydromuconic, bromo-maleic and methylene malonic acids. As suitable polyhydric alcohols there are specified glycols, glycerol, trimethylol propane, 1,6-3, hexanetriol, triethanolamine, pentaerythritol, sorbitol, glycerol pentachlorophenyl ether and trimethylolpropane monophenyl ether. Also suitable as polyols in the preparation of the partial esters are alkoxylated polyhydric alcohols, polyesters having terminal OH groups, and polyester ethers obtained by reacting excess alkoxylated alcohols with oxalic, malonic, succinic, glutaric, adipic, pimelic, suberic, azelaic, sebacic, brassylic, thapsic, a -butyl-a -ethyl glutaric, a ,b -diethyl succinic, isophthalic, terephthalic, hemimellitic, trimellitic, trimesic, mellophanic, prehnitic, pyromellitic, benzenepentacarboxylic cyclohexane dicarboxylic and 3,4,9,10-perylene tetracarboxylic acids. Halogen-containing polycarboxylic acid and polyhydric alcohols are also listed. Suitable phosphites contain as the organic groups chlorethyl bromoethyl, methyl, ethyl, butyl, chloro- or bromo-propyl, dodecyl, allyl, methallyl, benzyl, pentachlorobenzyl or hexadecyl radicals. Diallyl methyl phosphite and dibenzyl-b -chlorethyl phosphite are also mentioned. Preferred phosphorus-containing polyesters have a hydroxyl number from 100 to 400 and a molecular weight of from 500 to 5000. In the preparation of polyurethanes they may be mixed with other polyesters or with polyhydric polyalkylene ethers before the reaction with polyisocyanates. Cross-linking agents, for example water, ethylene glycol, butane diol, p-bis-b -hydroxyethyl benzene and ethylene diamine may also be present in the reaction mixture. In preparing cellular products water, halohydrocarbons, azo compounds and low-boiling alkanes are suitable blowing agents. There may also be present emulsifiers such as sulphonated castor oil, foam stabilizers such as silicones (e.g. the block copolymers described in U.S.A. Specification 2,834,748), colouring agents, catalysts triethylene diamine, N-methyl, ethyl, or N-coco-morpholine, diethyl ethanolamine, 1-methyl-4-dimethylaminoethyl piperazine, 3-methoxy-N-dimethylpropylamine, N-dimethyl-N-methyl isopropyl propylene diamine, N,N,-diethyl-3-diethylamino propylamine, dimethylbenzylamine, molybdenum glycollate, stannous chloride, dibutyl tin di-2-ethyl hexoate and stannous octoate. Non-porous plastics can be produced by reacting the organic polyisocyanate with sufficient polyester to give a hydroxyl group-containing product which is cross-linked by reaction with an organic peroxide, sulphur or formaldehyde. Castings can also be prepared from -NCO containing prepolymer and cross-linking agent. Coating compositions are obtained by dissolving the organic polyisocyanate/polyol adherent containing NCO groups (which may be blocked) in a solvent such as xylene, ethyl acetate, toluene or ethylene glycol monoethyl ether acetate. In examples (1) a polyester is prepared by reacting tri-b -chlorethyl phosphite with a partial ester prepared from propoxylated trimethylol propane, trimethylol propane and maleic anhydride. The product is mixed with an adipic acid/phthalic anhydride/trimethylol propane/oleic acid polyester and foaming is effected by addition of permethylated aminoethyl piperazine, oxyethylated polysiloxane, aqueous sodium castor oil sulphate and 4,41-diphenylmethane diisocyanate. Specification 804,369 also is referred to.