Blocked isocyanate compositions

摘要

A composition comprises a blocked isocyanate and a compound of general formula:- where X1 is a halogen atom, a hydroxyl radical, a lower alkoxy radical, a carboxylic acyloxy radical, an -NCO or -NCS radical, X2 is a hydroxyl, lower alkoxy or carboxylic acyloxy radical, or -NCO or -NCS with the proviso that X2 is not a hydroxyl radical when X1 is an -NCO or -NCS radical, and vice-versa, and each of R1, R2, R3 and R4 is a lower alkyl radical.ALSO:An isocyanate composition comprises a blocked isocyanate and a compound of formula where X1 is a halogen atom, a hydroxyl radical, a lower alkoxy radical, a carboxylic acyloxy radical, an NCO or NCS radical, X2 is a hydroxyl, lower alkoxy, or carboxylic acyloxy radical, or NCO or NCS radical with the proviso that X2 is not a hydroxyl radical when X1 is an -NCO or NCS radical and vice versa, and each of R1, R2, R3 and R4 is a lower alkyl radical. The blocked isocyanate may be obtained by blocking (e.g. with phenol) a monomeric aliphatic or aromatic polyisocyanate or a prepolymer derived from a monomeric polyhydroxy compound or a polyether or polyester polyol. An additional compound may be present in the composition, e.g. a polyether or polyester polyol. Blocking agents mentioned include: phenols, alcohols, fluoroalcohols, amines, imides, active methylene compounds, mercaptans, lactams, imines, ureas, oximes, carbazole, bisulphates and thorates. Many stannoxanes are listed. In Examples: (1) diphenylmethane 4,41-diisocyanate blocked with phenol is mixed with tetra n-butyl-1,3-di-acetoxy-distannoxane and a polyester derived from adipic acid, butylene glycol and 1,2,6-hexane triol in toluene and heated; (3) a pre-polymer derived from tolylene diisocyanate and oxypropylated glycerol was blocked with m-cresol, dissolved in ethyl acetate and mixed with tetra - n - butyl - 1,3 - diacetoxy - dis-tannoxane and emulsified with water and a sulphosuccinate emulsifier, applied to a glass plate and heated.ALSO:Emulsion baking paints are prepared by mixing a diluted polyisocyanate with a stannoxane and an active hydrogen containing compound and dissolving or emulsifying the composition in a solvent e.g. butyl acetate, acetone, benzene, xylene. The stannoxane has the general formula: where X1 is a halogen atom, hydroxyl, lower alkoxy, carboxylic acyloxy, -NCO or -NCS, X2 is a hydroxyl, lower alkoxy, -NCO or -NCS carboxylic acyloxy, with the proviso that X2 is not a hydroxyl when X1 is -NCO or -NCS or vice versa, and each of R1, R2, R3, R4 is a lower alkyl radical. The active hydrogen containing compound may be a polyol, amino alcohol, diamiac or hydrazine. The leaking paints can be applied to metals, wood, plastics, leathers, fabrics, and rubbers. In Example (2) the reaction product of excess tolyrene diisocyanate and trimethylol propane was diluted with phenox, dissolved in ethyl acetate and mixed with tetra-n-propyl 1-chloro - 3 hydroxy - distannoxane and a polyester polyol, and the mixture applied to metal plates and heated to cure. In other Examples similar compositions are applied to glass plates (3), (4) and (5); metal plates (6); iron plates (7), (9) and (16); vulcanized rubber sheet (10) and (11); non woven fabric (14) and cotton cloth (15).ALSO:An impregnation agent for fabrics, non woven fabrics, cloths, papers and plastics sheets is prepared by emulsifying with a solvent a temposition comprising (a) a blocked isocyanate (b) a stannoxane of formula p where X1 is halogen, hydroxyl, lower alkoxy, carboxylic acyloxy, -NCO or NCS and X2 is hydroxyl, lower alkoxy, carboxylic acyloxy, -NCO or -NCS with the proviso that X2 is not hydroxyl when X, is -NCO or -NCS and vice versa and each of R1, R2, R3 and R4 is a lower alkyl radical (c) an active hydrogen containing compound. In Example (14) an isocyanate containing prepolymer was blocked with phenal and mixed with tera -n-butyl 1, 3 diacryloxy -distannoxane and a polyester polyol and emulsified with water. Non woven fabrics were dipped in the emulsion, squeezed and heated for 30 mins at 110 DEG C. In Example (15) a similar composition was used to render cotton cloth water proof.