| 摘要 |
Polyurethanes are prepared by reacting (a) an organic polyisocyanate with (b) the reaction product of a drying or semi-drying vegetable oil (or unsaturated acids therefrom), a polyhydric alcohol of molecular weight below 500 and having 2 to 6 hydroxyl groups and from 2 to 25% by weight (calculated on the total weight of the reaction product and polyisocyanate) of a copolymer of an ethylenically unsaturated monohydric alcohol and an alkenyl substituted aromatic compound. The isocyanate may be ethylene, ethylidene, propylene-1, 2, cyclohexylene-1, 2, m-phenylene, 2, 4-toluylene, 2, 6-toluylene, 3, 31-dimethyl-4, 41-biphenylene, 3, 31-dimethoxy-4, 41-biphenylene, 3, 31-di-phenyl-4, 41-biphenylene, 4, 41-biphenylene, 3,31-dichloro-4,41-biphenylene, 1,5-naphthalene or furfurylidene diisocyanate or triphenyl-methane triisocyanate. Blocked polyisocyanates, e.g. the phenyl carbamates thereof, may be used. Specified oils are linseed, safflower, corn, sunflower, perilla, china wood, oiticica, poppyseed, tall, sesame and soya bean oils. The polyhydric alcohol may be ethylene glycol, propylene glycol, 1, 4-butanediol, diethylene glycol, di-propylene glycol, thiodiglycol, glycerine, trimethylol propane, 1, 2, 6-hexane triol, pentaerythritol, N, N, N1, N1-tetrakis-2-hydroxy-propyl ethylene diamine, methyl glycoside, arabitol, mannitol or sorbitol. The copolymer may be derived from allyl, chlorallyl, methallyl, b -ethyl allyl, b -propyl allyl or b -phenyl allyl alcohol and styrene, p-chlorostyrene, m-chlorostyrene, m-ethylstyrene, p-ethoxystyrene, p-ethyl-styrene, p-butylstyrene, p-octylstyrene, vinyl-toluene, 2, 5-dimethylstyrene, 2, 5-diethylstyrene, 2, 5-dipropylstyrene, 2, 5-dibutylstyrene, b -vinyl-naphthalene, 2, 4-dichlorostyrene, 2, 4-dibromostyrene or allyl benzene. Reaction may be effected in the presence of a catalyst, e.g. calcium naphthenate, lead naphthenate, litharge or sodium hydroxide. The products may be used for coating wood and metals. They may be mixed with solvents, e.g. xylene, benzene, toluene, naphtha, mineral spirits and turpentine, driers and colouring matter, e.g. chrome yellow, carbon black, iron oxide, titanium dioxide, zinc oxide, aluminium flakes and organic pigments. Examples describe the reaction of toluylene diisocyanate with the reaction products of styrene-allyl alcohol copolymers, glycerol and (1 and 2) linseed oil and (3 and 4) tall oil fatty acids.ALSO:Substrates, e.g. metals, wood and glass, may be coated with polyurethanes prepared by reacting (a) an organic polyisocyanate with (b) the reaction product of a drying or semi-drying vegetable oil (or unsaturated acids therefrom), a polyhydric alcohol of molecular weight below 500 and having 2-6 hydroxyl groups and 2-25% by weight (calculated on the total weight of reaction product and polyisocyanate) of a copolymer of an ethylenically unsaturated monohydric alcohol and an alkenyl substituted aromatic compound. Specified metal substrates are steel, copper and aluminium, which may be primed or unprimed. Specified oils are linseed, safflower, corn, sunflower, perilla, china wood, oiticica, poppyseed, tall, sesame and soya bean oils. Many suitable polyisocyanates, polyhydric alcohols, unsaturated monohydric alcohols and aromatic compounds are listed, the preferred reactants being toluylene diisocyanate, glycerol and styrene-allyl alcohol copolymers. Examples describe the coating of (1) steel and glass panels and (2) steel panels with a polyurethane formed from toluylene diisocyanate and the reaction product of linseed oil, glycerol and a styrene-allyl alcohol copolymer, and (3) steel panels with a polyurethane formed from toluylene diisocyanate and the reaction product of tall oil fatty acids, glycerol and a styrene-allyl alcohol copolymer. Coatings may be applied from solutions in organic solvents, e.g. xylene, benzene, toluene, naphtha, mineral spirits and turpentine, and the compositions may also comprise driers, e.g. the naphthenates, linseedates and tallates of cobalt, lead, manganese, zirconium and rare earth metals, and colouring matter, e.g. chrome yellow, carbon black, iron oxide, titanium dioxide, zinc oxide, aluminium flakes and organic pigments. |
