GB932075A - Improvements in the preparation of petroleum resin emulsions - Google Patents

Abstract

Polyaromatic petroleum resin emulsions of improved stability are prepared by plasticizing the resin in the melted state with a hydrocarbon plasticizer, adding a non-ionic emulsifier to the plasticized resin, cooling the mixture to a temperature below 100 DEG C. but above the softening point of the plasticized resin, maintaining the temperature, while adding water until the emulsion is changed from the water-in-oil type to the oil-in-water type. The polyaromatic petroleum resins are defined as the thermoplastic resins obtained by the distillation of tar produced in the steam cracking of petroleum fractions. The preferred petroleum resins have a softening point within the range 70 DEG -100 DEG C., an acid index of less than 1 and a saponification index of less than 1. Plasticizers used include oily liquid hydrocarbons having a viscosity above 120 centi-stokes at 50 DEG C. and liquid polymers or copolymers of conjugated diolefines containing 4-6 carbon atoms in the molecule. Polymers derived from steam cracked petroleum resins may also be used. The molecular weight of the plasticizers may be in the range 500-15,000. Non-ionic emulsifiers used are a mixture of from 30-5% by weight of a lipophilic emulsifier and from 70-95% by weight of a hydrophilic emulsifier. Specified lipophilic emulsifiers are (a) Condensation products of compounds of formula R-CO-NH2 where R is a C3-C18 alkyl radical, wherein a molecule of the fatty amide has been condensed with 1-15 molecules of an alkylene oxide containing 2-6 carbon atoms; (b) Condensation products of monoesters of polyglycols with diethanolamine; (c) Condensation products of tertiary dodecyl mercaptans and ethylene oxide. Hydrophilic emulsifiers used are condensation products of cresol, xylol, or alkyl phenols, where the alkyl chain contains 3-18 carbon atoms with 1-25 molecules of an alkylene oxide containing 2-6 carbon atoms. Preferably the petroleum polyaromatic resin is plasticized at 100 DEG -150 DEG C., the plasticizer being used in proportions of 10-50% by weight per 90-50% by weight of the polyaromatic resin based on the plasticized mixture. The melted mixture of plasticizer and resin is cooled with stirring to 85 DEG -95 DEG C. and 1-20% by weight in relation to the total weight of the mixture of resin and plasticizer thereafter added in portions. Mixing is continued and water is added at the same temperature to form a water in resin emulsion which reverses to form a resin in water emulsion having a p mean particle dimension of 1 micron, a pH range of 8-10 and a solids content of about 50%. The emulsions have high stability mechanically and are also stable to acids, bases or electrolytes. They may be used for impregnating or coating paper board and fibrous material to improve gloss or finish, resistance to adhesion, wear or colour change, moisture and grease; and to give sound proofing properties by applying them to a metal surface, thereafter applying a paste of fibre and these emulsions and then drying. They may be mixed with other thermoplastic or thermosetting polymers.ALSO:Aqueous emulsions comprising a thermoplastic resin obtained by the distillation of tar produced in the steam-cracking of petroleum fractions, plasticizer and non-ionic emulsifier (see Group III) are used for impregnating paper board and fibrous p materials of a similar type to improve gloss or finish as well as resistance to adhesion, wear or colour change and to give the property of withstanding moisture and grease. The emulsions may be mixed with other thermoplastic or thermo-setting polymers. Specified plasticizers are of hydrocarbon type and specified emulsifiers are mixtures of polyether type.