| 摘要 |
<p>Coating compositions comprise 100 parts by weight of an epoxy resin which is a glycidyl ether of a polyhydric phenol having an epoxy equivalent between 140 and 400, 35 to 70 parts by weight of a ureaformaldehyde resin, 8 to 20% (based on the combined weight of epoxy and urea resins) of an epoxidized fatty acid ester oil having a molecular weight between 800 and 1500 and oxinane oxygen content of 1 to 5%, 2 to 10 parts by weight (calculated as H3PO4) of a phosphoric acid of the formula <FORM:0998893/C3/1> wherein R1 and R11 are hydrogen or alkyl radicals of 1 to 8 carbon atoms, and a suitable solvent. The urea-formaldehyde resin may be alkylated. Optional additives include surface tension reducers such as silicone oil and anti-static agents such as a quaternary ammonium-chloride. The compositions may be aged before use until 10% of the epoxide groups of the epoxy resin have reacted with the urea-formaldehyde resin.ALSO:A process for applying a hard, glossy coating to a plastic article formed of a solid polymer of an alkene of 2 or 3 carbon atoms comprises forming a coating solution by dissolving 100 parts by weight of a glycidyl ether of a polyhydric phenol having an epoxy equivalent of 140-400, 35-70 parts by weight of a urea-formaldehyde resin, 8-20% (based on the combined weight of epoxy and urea resins) of an epoxidized fatty acid ester oil having a molecular weight between 800 and 1500 and an oxirane oxygen content of 1-5% in a ketone solvent having a boiling point of 150-180 DEG F. to give a solution having a viscosity of 8-15 cp., adding to the solution 2-10 parts (calculated) as H3PO4 of phosphoric acid, ageing the solution to react 10-25% of the epoxide groups of the epoxy resin with the urea resin, applying the solution to the article, drying and curing the coating on the article by exposing the coated article to a temperature of 175-200 DEG F. for 8-20 minutes. The solution may contain a flow control agent such as a silicone oil and an anti-static agent such as a quaternary ammonium salt. The solution may be applied by spraying or dipping. The preferred articles are flexible polythene bottles.</p> |
