| 摘要 |
A prepolymer, an ingredient in electric insulating lacquers, is prepd. by condensation between adipic acid and glycols in the presence of 0.01-0.0.5 mol zinc acetate, which reduces the tendency of, polymer rotation. Based on 1 mol adipic acid, 1.05-1.15 mols of monomers of general formula are used CH2-OH-CH2-CHOH-R , where R is a methyl, ethyl or propyl gp. The reaction temp. is increased at a rate of 50 deg./hour up to 120 deg.C, followed by a 10 deg./hour increase to 150 deg.C. The mix is kept for 5 hours at this temp., prior to continuing the condensation in vacuo with an acidity index maximum of 15mg koh/g is reached.
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