GB792842A - Improvements in pressure sensitive adhesives and adhesive tapes - Google Patents

Abstract

A pressure sensitive adhesive is prepared by blending an aqueous latex with a solution of a thermosoftening resinous tackifier in a volatile solvent that is a swelling agent for the rubber, to form a blend containing 30 to 200 parts by weight of tackifier per 100 parts by weight of rubber and an amount of volatile solvent greatly in excess of the amount of water, and converting the blend to a smooth continuous viscous rubbery liquid in which the water is dispersed in a continuous phase. In one example 167 parts by weight of concentrated Hevea latex (60 per cent rubber) are added with agitation to a solution of 100 parts terpene resin tackifier in 1010 parts heptane. A solution of 2 parts alkylated polyhydroxy phenol antioxidant in 100 parts ethyl-isobutyl, or isopropyl alcohol is then added with continued agitation. Gum, wood, or limed rosin, an ester gum such as glycerol or pentacrythritol abietate or hydrogenated indene polymers may be used in place of the terpene resin tackifier. In a further example the solution of tackifier resin contains as a plasticizer, lanolin and/or tricresyl phosphate, dioctyl phthalate, or mineral oil, and the latex contains kaolin or other filler, e.g., hydrated alumina, hydrous aluminium silicate, or zinc oxide. Carton sealing adhesive tape may be prepared by applying the pressure sensitive adhesive composition to one side of a fibrous sheet, the fibres of which have been lightly coated with polychloroprene, the other side of the sheet being coated with a non-adhesive coating, e.g., as described in Specifications 645,057 and 683,927 [both in Group VIII].