Patent GB-312610-A (GB)
Title: Improvements in or relating to adhesive tapes or sheets
IPC: C09J7/21
Filed: 1929-05-27
Abstract: 312,610. Minnesota Mining & Manufacturing Co., (Assignees of Drew, R. G.). May 28, 1928, [Convention date]. Drawings to Specification. Adhesive bandages. - Adhesive tape or sheet utilizable for surgical purposes consists of a pressure sensitive adhesive united to one side or a portion of one side of a strip or sheet of cellulosic backing, there being greater adhesion between the adhesive and the backing than between the adhesive and a surface to which the tape &c. is to be applied. The adhesive must have a cohesion inter se greater than its adhesion to the surface to which the tape is to be attached, and the backing is a sheet of paper the elements of which are held together with greater cohesion inter se than the adhesion of the adhesive to the surface. The paper may be made up in strip form, or it may comprise coated sheets, or sheets having a strip of such adhesive-coated paper around and overlapping its edges. The adhesive may comprise plasticized plantation rubber, Cumaron gum or resin or other polymerization products of coal-tar derivatives, and zinc oxide, compounded in a rolling mill to a plastic condition and them dissolved in a solvent such as benzol or petroleum. A low boiling point natural resin, for example Burgundy pitch or pine oil foots, may be used in place of the Cumaron gum. In another example, plantation rubber, zinc oxide and a Mexican or wild rubber having a high natural resin content may be used. Benzol, petrol, acetone, or alcohol is used to remove the strip after use, and the resin is chosen according to its solubility in the solvent to be used. In a surgical tape where alcohol is used for removal, an alcohol soluble resin such as Burgundy pitch is used. The adhesive composition may be spread directly upon the paper, or a priming layer may be applied. This priming layer may comprise 100 parts by weight of milled plantation rubber rendered plastic by mixture with 7¢ parts of phenolsulphonic acid, heated in sheet form to 135- 140 C. for six hours and then dissolved in benzol to form an extremely liquid solution. Toluenesulphonyl chloride or toluenesulphonic acid may be used in place of phenolsulphonic acid. To prevent the material from sticking when rolled up, a finishing coat may be applied to the back of the paper. This coat comprises plantation rubber dissolved for example in benzol, the solution being treated by bubbling a small stream of chlorine gas through it at low temperature. To ensure that the cohesion of the paper is sufficient to prevent lamination or disruption when being removed from the surface to which it is applied, it is treated with glycerine or with a glue-glycerine mixture before applying the adhesive. When the paper base is of the unsized, uncalendered variety, the glue-glycerine solution may be rendered insoluble by formaldehyde treatment or bv treatment with a sodium carbonate solution of gallic and tannic acids, chromium trioxide and chrome alum or other chrome and aluminium salts. Examples of the proportions of glue and glycerine are given. One face only may be submitted to the formaldehyding process. In place of glycerine, sulphonated oils such as Turkey red oil or sulphonated castor oil may be used.