Patent GB-841203-A (GB)
Title: Improvements in or relating to cements
IPC: B31F1/00
Filed: 1956-10-10
Abstract: A coating of a cement comprising incompatible resinous materials in intimate admixture is produced on a workpiece by progressively feeding a flexible rod of such a mixture into an apparatus which melts it and applies it to the workpiece at a controlled rate, and wherein a small portion only of the cement is held molten at any one time and that only for a short period, the molten cement in the apparatus being continually removed and applied to the workpiece while fresh cement is fed into the apparatus for melting.  Suitable mixtures include hydrocarbon resins and epoxy resins with or without the addition of rubbery polymers.  Examples are given of compositions containing (1) and (2) polythene, beta-pinene polymer, isobutylene-isoprene copolymer and an epoxide resin; (3) polythene, beta-pinene polymer, butadiene-acrylonitrile copolymer, and an epoxide resin; and (4) polythene, fossil rubber resin, isobutylene-isoprene copolymers, and an epoxy resin.  In each of the examples there is also added 4-methyl-2 : 6-ditertiary butyl phenol as antioxidant.  The epoxide resins may be glycidyl polyethers of polyhydric phenols, of polyhydric alcohols, or of both; or the reaction products of polyhydric phenols such as diphenylol propane, bis-phenol, hydroquinone or resorcinol with polyfunctional chlorhydrins such as epichlorhydrin or glycerol dichlorhydrin; or the reaction products of polyhydric alcohols with polyepoxides.  An alternative hydrocarbon resin specified is a polymer of mixed unsaturated monomers derived from cracked petroleum.  And alternative rubbery polymers specified are polyisobutylene and a copolymer of isobutylene with butadiene.ALSO:<PICT:0841203/III/1> A coating of a cement comprising incompatible resinous materials in intimate admixture is produced on a workpiece by progressively feeding a flexible rod of such a mixture into an apparatus which melts it and applies it to the workpiece at a controlled rate, and wherein a small portion only of the cement is held molten at any one time and that only for a short period, the molten cement in the apparatus being continually removed and applied to the workpiece while fresh cement is fed into the apparatus for melting.  Suitable mixtures include hydrocarbon resins and epoxy resins with or without the addition of rubbery polymers.  Examples are given of compositions containing (1) and (2) polythene, beta-pinene polymer, isobutylene-isoprene copolymer and an epoxide resin; (3) polythene, beta-pinene polymer, butadiene - acrylonitrile copolymer, and an epoxide resin; and (4) polythene, fossil rubber resin, isobutylene-isoprene copolymers, and an epoxy resin.  Apparatus for carrying out the process includes a roll 18 of cement rod, two feed rollers 24 and a wheel 28 located mainly within a casing 25, heated by heater 26, that part of the wheel which protrudes from the casing acting as the applying member. Blanks 48 of aluminium foil coated fibre board for the manufacture of containers are fed past this member, pressed against it by roller 60 and so obtain a coating of cement. The passageway 12 in the casing is not of substantially greater dimensions than the rod of cement, so that softened and unsoftened portions of the rod are moved forward at approximately the same rate, and only a small amount is thus in the molten condition at any one time.