GB1003201A - Improvements in or relating to the manufacture of polyurethanes - Google Patents

Abstract

A process for the manufacture of polyurethanes by the reaction of organic polyisocyanates with hydroxyl group containing polymers is characterized in that the said reaction is carried out in the presence of a complex compound of a stannous salt with an organic ligand which is an ether, a substituted amide a triester of phosphoric acid or a sulphoxide, provided that such a ligand contains no grouping reactive with an isocyanate group. The stannous salt may be the chloride, bromide, fluoride, sulphate, orthophosphate, hypophosphite, octaphosphate, oxalate, tartrate, acetate, butyrate, hexoate, octoate, oleate or p-toluene sulphonate. Suitable ethers are: di-n-propyl ether, di-n-butyl ether, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, dioxan, tetrahydrofuran, tetrahydropyran, ethylene propylene and butylene oxides. Substituted amides may be: dimethyl and diethyl formamides, dimethylacetamide and N-methylacetamide. Suitable triesters of phosphoric acid are tri-n-butyl phosphate, tri-(b -chloroethyl) phosphate, triethylphosphate, triphenyl phosphate, dimethylethyl phosphate, tribenzyl phosphate and tricyclohexyl phosphate. Sulphoxides mentioned are: dimethyl, diethyl and dibutyl sulphoxides. The polyurethane may be derived from a polyether, polyester or polyesteramide which may have a molecular weight of 200-5000. Many conventional polyisocyanates are listed. Foamed polyurethanes may be prepared by use of a conventional blowing agent. Polymers having mainly secondary hydroxyl groups e.g. those derived from propylene glycol, 13-butylene glycol or glycerol are suitable for foam preparation. A large number of tertiary cyclic amines for use as catalysts are listed. In a typical Example (10) a mixture of oxypropylated glycerol, siloxane foam stabilizer, 4-dimethyl amino-pyridine, water and various tin complexes were mixed with tolylene diisocyanate to form a foam. The tin complexes used were those of stannous chloride with tetrahydrofuran, dioxan, diethylen glycol dimethyl ether, tributyl phosphate, tri-(b -chloro-ethyl) phosphate, dimethyl formamide, dimethyl sulphoxide and stannous sulphate with dioxan.ALSO:Complex compounds of a stannous salt with an organic ligand which is an ether, a substituted amide, a triester of phosphoric acid or a sulphoxide, provided that such ligand contains no grouping reactive with an isocyanate group are used to catalyse polyurethane formation. The stannous salt may be the chloride, bromide, fluoride, sulphate, or the phosphate, hypophosphite, metaphosphate, oxalate, tartrate, acetate, butyrate, hexoate, octoate, oleate or p-toluene sulphonate. Suitable ethers are: di-n-propyl ether, di-n-butyl ether, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, dioxan, tetrahydrofuran, tetrahydropyran, and ethylene propylene and butylene oxides. Substituted amides may be: diethyl and dimethyl formamides, dimethyl acetamide and N-methyl acetamide. Suitable triesters of phosphoric acid are tri-n-butyl phosphate, tri - (b - chloroethyl)phosphate, triethylphosphate, triphenyl phosphate, dimethyl ethyl phosphate, tribenzyl phosphate and tricyclohexyl phosphate. Sulphoxides mentioned are: dimethyl, diethyl and dibutyl sulphoxides. Examples describe the preparation of complexes of stannous chloride with (1) dioxan, (2) tetrahydrofuran, (4) diethylene glycol dimethyl ether, (5) tributyl phosphate, (6) tri-(b -chloroethyl)phosphate; (7) and (8) dimethyl formamide, (9) dimethyl sulphoxide, (14) N,N-dimethylacetamide, (3) stannous sulphate and dioxan, (11) stannous acetate and dimethyl formamide, (12) stannous oxalate and dimethyl formamide, (13) stannous-p-toluene sulphonate and dimethyl formamide, (15) stannous chloride dihydrate and N,N-dimethyl acetamide.