PROCESS FOR THE MANUFACTURE OF THERMOSETTING PLASTIC MOULDED ARTICLES HAVING A GLOSSY STAIN RESISTANT SURFACE

摘要

1352628 Epoxy coated melamine articles CIBA-GEIGY AG 3 Nov 1971 [4 Nov 1970] 51130/71 Heading B5A [Also in Division B2] Articles such as tableware and canteen utensils made from urea, melamine-formaldehyde resins or melamine-formaldehyde resins modified with aceto- or benzoquanamine are provided with epoxy coatings to reduce food staining. To coat an article, powdered or granulated epoxide resin/hardener mixture or, precondensate is applied to the surface of a partially cured article blank contained in a mould at an elevated temperature, e.g. 150, 155‹ C. The mixture or precondensate melts, flows over the surface of the blank and the coating and blank are fully cured to form an article, e.g. a plate. A decorative foil may be applied to the article blank prior to the coating constituents. The epoxide resin/hardener mixture may comprise crystalline triglycidyl isocyanurate and an adduct hardener formed from an epoxide resin e.g. a polyglycidyl ether of resorcinol or a diglycidyl ether of 2,2-bis-(p-hydroxyphenyl)- propane, i.e. diomethane diglycidyl ether and a cycloaliphatic primary amine such as 1,2- diaminocyclohexane, bis-(4-amino-cyclohexylmethane, bis - (3 - methyl - 4 - aminocyclohexyl)methane, 3 - aminomethyl - 3,5,5 - trimethyl - cyclohexylamine - 1,2,2 - bis - (4 - aminocyclohexyl)propane or N - cyclohexyl - 1,3- diamino - propane. The precondensate may comprise the reaction product of crystalline triglycidyl isocyanurate and bis-(3-methyl-4- aminocyclohexyl, (31,41 - epoxy - cyclohexylmethyl) - 3,4 - epoxy - cyclohexane - carboxylate, 5,5 - diethylbarbituric acid and tetraethylammonium chloride or 3-aminomethyl- 3,3,5 - trimethylcyclohexylamine - 1, diomethanediglycidyl ether and the epoxide prepared by reacting epiohlorohydrin with alkaline 2,2 - bis - (p - hydroxyphenyl)propane. The latter precondensate is fully cured using phthalic anhydride. The coating may include additives such as pigments, e.g. titanium dioxide, iron oxide, cadmium red, nigrosine, mould release agents such as stearic acid, stearyl alcohol, zinc stearate, fillers such as silica and optical brighteners.