PROCESS FOR PREPARING ALKYD RESINS Russian patent published in 1996 - IPC

FIELD: paint industry. SUBSTANCE: oil is reacted with glycerol and/or pentaerythrite at 220-240 C in the presence of basic type catalyst. Phthalic anhydride and modifier are thereafter added at their molar ratio of 1:(2-6) respectively, and the process is continued at 170-180 C to give alkyd resin with acid number of not greater than 40 mg KOH/g. The modifier is tetrahydrophthalic acid anhydride selected from the group consisting of tetrahydrophthalic anhydride, 3-or 4-methyl tetrahydrophthalic anhydride, isomethyl tetrahydrophthalic anhydride. The resulting resins are dissolved in toluene, siccative is added, and the resulting varnish is applied onto metal and glass plates which are subjected to hot drying at 130 C for 30 minutes. The coatings have improved hardness values (0.45-0.8) conventional units). EFFECT: more efficient preparation process. 1 tbl