GB488557A - Improvements in or relating to adhesive compositions - Google Patents

Abstract

A permanently tacky adhesive composition, in the form of an emulsion containing water as the discontinuous phase, is obtained by mixing, with heat, or fusible resin with a non-drying oil or fatty acid derived therefrom and then incorporating into the mixture a small proportion, not exceeding 10 per cent by weight of the total composition, of rubber in the form of an aqueous dispersion. Prior to incorporating the rubber a small proportion of water containing an alkaline substance such as ammonia may be emulsified into the resin mixture. In an example (1) a mixture of colophony and castor oil is heated at 120 DEG C. until homogeneous, cooled to 90-95 DEG C. and an aqueous solution of ammonia added gradually with constant stirring, then further cooled to 50 to 60 DEG C. and rubber latex added while keeping the mixture agitated. In further examples, ammonia and rubber latex are similarly incorporated into mixtures of (2) oleic acid and wood resin, (3) wood resin and resin oil, (4) colophony and mineral oil and (5) castor oil and a phenol-formaldehyde resin formed by heating, by weight, 50 parts each of phenol and 40 per cent formaldehyde and 5 parts concentrated hydrochloric acid until an exothermic reaction develops, cooling to moderate the reaction and continuing until a viscous syrup-like layer separates and pouring this into cold water, washing the solid plastic by kneading in warm water and drying; the resin is dissolved in warm alcohol and the solution stirred into castor oil at 60 DEG C. the alcohol being then removed by heating to 80-90 DEG C.ALSO:A permanently tacky adhesive composition, in the form of an emulsion containing water as the discontinuous phase, is obtained by mixing, with heat, a fusible resin with a non-drying oil or fatty acid derived therefrom and then incorporating into the mixture a small proportion, not exceeding 10 per cent by weight of the total composition, of rubber in the form of an aqueous dispersion. Prior to incorporating the rubber a small proportion of water containing an alkaline substance such as ammonia may be emulsified into the resin mixture. In an example (1) a mixture of colophony and castor oil is heated at 120 DEG C. until homogeneous, cooled to 90-95 DEG C. and an aqueous solution of ammonia added gradually with constant stirring, then further cooled to 50-60 DEG C. and rubber latex added while keeping the mixture agitated. In further examples, ammonia and rubber latex are similarly incorporated into mixtures of (2) oleic acid and wood resin; (3) wood resin and resin oil; (4) colophony and mineral oil; and (5) castor oil and a phenol-formaldehyde resin formed by heating, by weight; 50 part each of phenol and 40 per cent formaldehyde and 5 parts concentrated hydrochloric acid until an exothermic reaction develops, cooling to moderate the reaction and continuing until a viscous syrup-like layer separates and pouring this into cold water, washing the solid plastic by kneading in warm water and drying; the resin is dissolved in warm alcohol and the solution stirred into castor oil at 60 DEG C., the alcohol being then removed by heating to 80-90 DEG C.ALSO:A permanently tacky adhesive composition in the form of an emulsion containing water as the discontinuous phase, is obtained by mixing, with heat, a fusible resin with a non-drying oil or fatty acid derived therefrom and then incorporating into the mixture a small proportion, not exceeding 10 per cent by weight of the total composition, of rubber in the form of an aqueous dispersion. Prior to incorporating the rubber a small proportion of water containing an alkaline substance such as ammonia may be emulsified into the resin mixture. In an example, (1) a mixture of colophony and castor oil is heated as 120 DEG C. until homogeneous, cooled to 90-95 DEG C. and an aqueous solution of ammonia added gradually with constant stirring, then further cooled to 50-60 DEG C. and rubber latex added while keeping the mixture agitated. In further examples, ammonia and rubber latex are similarly incorporated into mixtures of (2) oleic acid and wood resin, (3) wood resin and resin oil, (4) colophony and mineral oil, and (5) castor oil and a phenolformaldehyde resin formed by heating, by weight, 50 part each of phenol and 40 per cent formaldehyde and 5 parts concentrated hydrochloric acid until an exothermic reaction develops, cooling to moderate the reaction and continuing until a viscous syrup-like layer separates and pouring this into cold water, washing the solid plastic by kneading in warm water and drying; the resin is dissolved in warm alcohol and the solution stirred into castor oil at 60 DEG C. the alcohol being then removed by heating to 80-90 DEG C.