GB878542A - Caulking compositions - Google Patents

Abstract

A stable, low-modulus caulk comprises as an essential constituent the polyurethane reaction product of (1) at least one polymeric polyol which is a polyalkylene-ether glycol or polyester, the polyol having an average molecular weight of 400-3,000, an acid number of less than 5 and an average of 2-3 free hydroxyl groups per molecule; (2) from 1,2-2,0 equivalents of at least one organic diisocyanate for each equivalent of polyol, and (3) from 0,003-0,0835 equivalents of monofunctional modifier selected from saturated primary alcohols, saturated primary amines and monofunctional saturated isocyanates for each equivalent of organic diisocyanate. In the figure for equivalents the last digit given is a significant figure in the mathematical sense. Substituted and unsubstituted polyalkylene ether glycols, linear polyesters, alkyd resins and aromatic, aliphatic and cycloaliphatic diisocyanates are listed. As the third component used in preparing the polyurethane there are specified methanol, ethanol, propanol, 2-methyl-propanol-1, butanol, hexanol, octanol, 2-ethylhexanol, decanal, octadecanal, benzyl alcohol, 2-cyclohexylethanol, 2-methoxy-ethanol, 4-acetoxybutanol; methylamine, ethylamine, propylamine, 2-methylbutylamine, n-hexylamine, octylamine, octadecylamine, 2-cyclohexylethylamine and benzylamine; phenyl, 4-tolyl, naphthyl, 4-chlorophenyl, butyl, hexyl, decyl, octadecyl, cyclohexyl, and tetrahydronaphthyl isocyanates. Nonslumping caulks are obtained by incorporating a finely divided particulate or fibrous antislumping agent, the particles preferably having a size of 0,01-0,04 microns and a surface area of 100-400 square metres per gram and the fibres preferably having a fibre length of 1/16 inch or less. Specified are titanium dioxide, silica, carbon black, zinc oxide, glass, aluminium oxide, talc; fibres of glass, polyacrylonitrile, polyamides, polyethylene, polyethylene terephthalate, wood flour, leather dust and asbestos. There may also be added fillers such as iron oxide, calcium carbonate, talc, magnesium oxide, diatomaceous earth, metal oxides, chromates, silicates, sulphides, sulphates and carbonates; plasticizers such as di (2-ethylhexyl) phthalate, or azelate, benzyl butyl phthalate, dibutyl phthalate, triphenyl phosphate, 2-ethylhexyl benzyl phthalate, low molecular weight polyurethanes, dicyclohexyl phthalate, triacetylated castor oil and epoxidized soy bean oil; antioxidants such as di-(p-tertiary butyl) cresol, 2-benzyl-6-tertiary butyl p-cresol, polymerized trimethyl dihydroquinoline, phenyl a - or b -naphthyl-amine, hydroquinone monobutyl ether and paraffin hydrocarbons. The caulks can be prepared by heating the polyalkylene-ether glycol or polyester with a solvent such as hexane, decane, xylene, benzene, toluene or naphtha with azeotropic distillation of water. Next the mixture is heated at 80 DEG -120 DEG C. with the organic diisocyanate, and after some hours the monofunctional reactant is added and heating is continued. After application the caulks cure under normal atmospheric conditions. Curing can be accelerated by subjecting to a more humid atmosphere or by adding to the composition a tertiary amine such as butylamine, trimethylamine, dimethyl dodecylamine or N-methyl morpholine.