GB425159A - Improvements in or relating to adhesive tapes or sheets and processes of making the same - Google Patents

Abstract

An adhesive tape or sheet comprises a backing such as paper which is saturated with a composition containing resin and a plasticizing agent therefor. The composition may be added directly to the paper mill heaters. The resin may be a natural resin such as rosin or a synthetic resin such as glycerol - phthalic anhydride or phenolic condensation resins. The plasticizing agent may be rubber such as latex cr<\>zepe, smoked sheet, reclaim, dispersions thereof such as latex or vulcanized rubber dispersions, or oils such as linseed oil or tung oil. The resin and plasticizer may be dissolved in a hydrocarbon solvent such as oleum spirits or xylol or dispersed in water. Fillers such as zinc oxide or whiting may be added. The rubber content of the saturated backing may be vulcanized. In preparing aqueous dispersions a small quantity of sodium hydroxide is added which forms a soap with the resin and acts as a dispersing agent. Synthetic resinous compositions may be prepared by condensing the constituent in the presence of oils with condensing agents such as acids. Linseed oil thickened by boiling and containing cobalt acetate may be used. The backing may be pre-treated with a more dilute solution or dispersion and may receive also a coating of a more saturated solution or dispersion. The backing may be coated on the non-adhesive side with an alcoholic shellac solution or a lacquer containing cellulose derivatives as cellulose acetate or nitro-cellulose. The composition is preferably applied to the paper by a flotation process similar to that described in Specification 425,151, [Group VIII], a second application given by immersion and the sheet festooned before drying in an oven. The pressure sensitive, normally tacky adhesive of the rubber-resin-zinc oxide type is then applied. Specification 312,610, [Class 140], is referred to.