| 摘要 |
A fast drying liquid coating vehicle is prepared by mixing (a) 94-99% by weight of (i) an alkyd resin modified with an unsaturated fatty oil (defined) or (ii) a copolymer of an unsaturated fatty oil with dicyclopentadiene or with a vinyl aromatic compound, said modified resin or copolymer containing at least 35% by weight of the unsaturated fatty oil and having an OH value of 20-100; (b) 1 to 6% by weight of a polyisocyanate consisting of a diisocyanate or a triisocyanate or a mixture thereof; (c) an inert organic solvent; and heating the mixture to obtain a stable fluid coating vehicle with a semi-gelled structure which is soluble in organic solvents. The term "fatty oil" is defined as those esters and acids of the drying type which are characterized as having one or more unsaturated chains containing 8-26 C. Examples are the oils of: linseed, safflower, tung, oiticica, rapeseed, corn, tall, soya, tuna, menhaden, anchovy and unsaturated fatty oils from animal and petroleum sources. The vinyl aromatic compound may be, styrene, vinyl toluene, alphamethyl styrene and divinyl benzene. The organic solvent may be: mineral spirits, naphtha, and kerosene. In Example (1) an alkyd resin containing about 60% tall oil, 17% phthalic anhydride and 23% glycerine was reacted wth toluene diisocyanate in mineral spirits. In Example (6) an alcoholized fatty-oil-dicyclopentadiene copolymer was prepared from crude menhaden oil, dicyclopentadiene and glycerine, and reacted with toluene diisocyanate in mineral spirits. In Example (8) styrene was copolymerized with the reaction product of linseed oil and glycerine and then reacted with toluene diisocyanate in mineral spirits. |
