Patent GB-952116-A (GB)
Title: Quick-drying urethane oil compositions
Inventor: SKRECKOSKI GERALD RAYMOND
IPC: C08G18/48
Filed: 1961-08-14
Abstract: A quick drying protective coating composition comprises a film-forming component (and optionally a drier) in a solvent, wherein the film-forming component is a reaction product of an organic polyisocyanate with a reactant mixture which comprises one or more polyol esters with or without one or more free polyols, the polyol esters being predominantly partial esters of unsaturated fatty acids characteristic of glyceride drying oils, at least one of the free or esterified polyols being a polyether polyol having a molecular weight above 500, to which 2 to 40% of the total free and esterified hydroxyl groups are bonded, and the reaction mixture being one containing 0.5 to 5.0 free hydroxyl groups for each ester linkage present, the relative proportions of organic polyisocyanate and reactant mixture being such that the ratio of the number of free isocyanate groups in the former to the number of free hydroxyl groups in the latter is above 0.8, the reaction product being free from unreacted isocyanate groups. The ester or ester-polyol mixture can be prepared by transesterifying a glyceride drying oil with polyol or by direct esterification with the unsaturated acid. The mixture is then reacted with the polyisocyanate with at least 0.8 and preferably 1.0 isocyanate groups per free OH group present. Solvent is added and if free isocyanate is present a stabilizer e.g. methanol is added, followed by catalysts or driers. Linseed, soybean, cotton seed, china wood, peanut, sunflower, prilla, oiticica, poppy seed, olive, talc, various fish and dehydrated castor oils can be used. Polyalkylene glycols and alkylene oxide reaction products of triols or tetrols are suitable polyols of M.W. above 500. Conventional lacquer solvents can be used in the compositions. Oil-soluble salts of lead, cobalt or manganese are suitable driers. The transesterification is effected at 200-250 DEG C. in the presence of a catalyst e.g. calcium naphthenate or litharge. The reaction with the polyisocyanate takes place at 70-85 DEG C., and some solvent may be added during the reaction. Stabilizers and driers are then added. In Example (1) a transesterification is effected between soybean oil, glycerol and a polyether triol (M.W.1100) from glycerol and ethylene and propylene oxides. A similar triol (but of M.W.3300) and dipropylene glycol are added. Reaction with tolylene diisocyanate and the addition of ethyl acetate is effected. Methanol, lead and cobalt naphthenates, ethyl acetate and hexane are added, and the solution is used to coat leather. In other examples coatings suitable for floor varnishes and spar varnishes are prepared from soybean or linseed oil.ALSO:To increase its resistance to abrasion leather is treated with a quick drying protective-coating composition comprising a film-forming component (and optionally a drier) in a solvent, wherein the film-forming component is a reaction product of an organic polyisocyanate with a reactant mixture which comprises one or more polyol esters with or without one or more free polyols, the polyol esters being predominantly partial esters of unsaturated fatty acids characteristic of glyceride drying oils, at least one of the free or esterified polyols being a polyether polyol having a molecular weight above 500, to which 2-4% of the total free and esterified hydroxyl groups are bonded, and the reaction mixture being one containing 0.5-5.0% free hydroxyl groups for each ester linkage present, the relative proportions of organic polyisocyanate and reactant mixture being such that the ratio of the number of free isocyanate groups in the former to the number of free hydroxyl groups in the latter is above 0.8, the reaction product being free from unreacted isocyanate groups.  The ester or ester-polyol mixture can be prepared by transesterifying a glyceride drying oil with polyol or by direct esterification with the unsaturated acid.  The mixture is then reacted with the polyisocyanate with at least 0.8 and preferably 1.0 isocyanate groups per free OH group present.  Solvent is added and if free isocyanate is present a stabilizer e.g. methanol is added, followed by catalysts or driers, linseed, soybean, cotton seed, chaina wood, peanut, sunflower, perilla, oiticica, poppy seed, olive, talc, various fish and dehydrated castor oils can be used. Polyalkylene glycols and alkylene oxide reaction products of triols or tetrols are suitable polyols of M.W. above 500. Conventional lacquer solvents can be used in the compositions. Oil-soluble salts of lead, cobalt or manganese are suitable driers.  The transesterification is effected at 200-250 DEG C. in the presence of a catalyst, e.g. calcium naphthenate or litharge. The reaction with the polyisocyanate takes place at 70-85 DEG C., and some solvent may be added during the reaction. Stabilizers and drier are then added. In Example (1) a transesterification is effected between soybean oil, glycerol and a polyether triol (M.W.1100) from glycerol and ethylene and propylene oxides.  A similar triol (but of M.W.3300) and dipropylene glycol are added. Reaction with tolylene diisocyanate and the addition of ethyl acetate is effected.  Methanol, lead and cobalt naphthenates, ethyl acetate and hexane are added, and the solution is used to coat leather.  The glossy finish produced is rendered matt by pressing against an unpolished platen at 90 DEG C.  The abrasion resistance of the treated leather is increased ten-fold.