| 摘要 |
<p>1534504 Epoxy-modified aminoplast resins BRITISH INDUSTRIAL PLASTICS Ltd 23 Sept 1975 [8 Oct 1974] 43435/74 Heading C3R [Also in Division B5] An aminoplast resin is obtained by reaction of an aminotriazine, formaldehyde and a monoepoxide in the molar ratio 1 : 2-4 : 0À01-0À2. Preferably it is a solution of viscosity 80-200 sec. in a British Standard E U-tube at 25‹ C.; the solution may be modified by addition of 0À1-30% of its weight of sucrose. Preferably melamine is heated with formalin and the monoepoxide in the ratio 1 : 0À5-1À5 : 0À01-0À2 in a C 1-3 alkanol at pH 9À5-11À5 at 60‹ C. up to reflux for 0À5-4 hrs., then formalin is added to a final M : F ratio of 1 : 2-4, heating at pH 7À5-9 at 40‹ C. up to reflux to the required viscosity. In Examples melamine is heated at reflux (85‹ C.) with formalin and octene oxide or a commercial monoepoxide in the ratio 1 : 0À75 : 0À016-0À053 in ethanol or isopropanol i.p.o. NaOH for 3 hrs.; formalin is then added to a final ratio of M : F of 1 : 2À5 or 3À5. The product solution, optionally with sucrose, is used to impregnate a print paper for lamination to chipboard.</p> |
