METHOD FOR PRODUCTION OF POLYETHYLENE COATING Russian patent published in 1994 - IPC

FIELD: production of polyethylene coating. SUBSTANCE: article surface is preliminarily treated with mixture containing, mas. part. : 35% hydrochloric acid 83.3; 85% phosphoric acid 12.5; 60% hydrofluoric acid 4.2, at temperature of 75-85 C for 5-15 min. Then, applied to treated surface is polyethylene film preliminary degreased in ethyl alcohol, and locking spacer of heat-resistant material inert to polyethylene is placed upon film. Locking spacer is used to press polyethylene film to article surface with force of 10^-3-10^-2 MPa. Then, article with applied polyethylene film and locking spacer is heated at residual pressure of less than 10^-2 Pa to temperature of 230-300 C and let then it stay at this temperature for 20-8- min. After article cooling, locking spacer is removed. To increase adhesion strength the article surface after treatment with acid mixture is treated with solution containing, mas. part: sodium bichromate 4, sulfuric acid 10 and water 30, at temperature of 74 deg. for 10 min. EFFECT: higher efficiency. 2 cl, 2 dwg