Abstract:
An adhesive for bonding polyethylene sheet to the same or other substances comprises a mixture of polyethylene and butyl rubber which dissolves in an organic solvent to give a composition stable at room temperatures. The mixture is prepared by working, e.g. by milling, at a temperature of around the softening-point of polyethylene, e.g. 225 DEG F., cooling, and continued working at a temperature below the softening-point of polyethylene, e.g. below 160 DEG F. After the first milling, the mixture is preferably sheeted out and allowed to stand overnight when an insoluble boardy material results. After remilling, the material is soluble in solvents such as toluol, xylol and naphtha. The ratio of polyethylene to butyl rubber is preferably between 1/4 : 1 and 4 : 1. The preferred polyethylenes have molecular weights of 10,000-20,000. Additional components which may be included in the composition are low molecular weight polyisobutylene, oil-soluble terpene resins, oil-soluble non-heat-reactive phenolic resins, oil-soluble maleic glyceride resins, and anti-oxidants such as hydroquinone monobenzyl ether and mono- and di-heptyl diphenyl amines. The solids content of the solutions should be from 20-80 per cent. The compositions may also be used as coating compositions and as adhesives for other substances, and the bonding of polyethylene sheet to the inside of a tank wagon and the flocking of cloth are described.