| 摘要 |
PURPOSE:To obtain the titled resin excellent in mechanical strength, by reacting a polyester resin with a mono-lower-alkyl terephtalate at a specified temperature by using an alkali metal carbonate and/or an alkali metal hydroxide. CONSTITUTION:A polyester resin (A) terminated chiefly with a hydroxyl group is obtained by reacting an acid component (a) (e.g., terephthalic acid) with an alcohol component (b) (e.g., ethylene glycol) and, optionally, at least trihydric polyalcohol (c) (e.g., trimethylolpropane). Component A is transesterified with a mono-lower-alkyl terephthalate (B) (e.g., monomethyl terephtalate) at 200 deg.C or below, preferably, 70-160 deg.C by using 2-200X10<-4>mol, per mol of component (a), of an alkali metal carbonate and/or an alkali metal hydroxide (e.g., Na2CO3) as a catalyst to obtain the titled resin of an acid value of 20-100KOHmg/g, a degree of polymerization of 4-50 and softening point of 50-150 deg.C.
|
