advances in surface treatment of structures containing polyethylene

摘要

The surface of a polythene film, tube or other structure is treated at 25 DEG to 95 DEG C., continuously with the extrusion of the product at a temperature between 150 DEG C. and the degradation temperature of the polythene into a quench bath, with an aqueous solution of a halogen, a hydrogen halide, hydrogen peroxide, nitrous acid or an alkaline hypochlorite, or with concentrated nitric acid or a mixture of concentrated nitric and sulphuric acids. The reagent may be employed in aqueous solution in the quench bath which may be agitated or subjected to sonic or supersonic vibrations or to ultra-violet light. The treatment is followed by neutralization in an aqueous solution of sodium hydroxide, or a mixture of sodium bicarbonate and hydrogen peroxide, and thereafter washing with water. The treatment improves the receptivity of the products for printing inks and coatings of cellulose derivatives or synthetic resins, and improves their adhesion properties in the production of polythene laminates or laminates of polythene with metals or paper, in which standard adhesives may be employed. The process may be extended to the treatment of products of copolymers of ethylene with isobutylene, vinyl acetate, styrene or vinyl chloride. A mixture of the reagents which does not impair the efficacy of the process may be employed. The process of extrusion includes the formation of films in heated calender rollers. Specifications 557,544 and 738,474 and U.S.A. Specification 2,430,860 are referred to.