| 摘要 |
PURPOSE:To provide a low-shrinking agent for use in thermosetting resin, consisting of a lactone polymer prepared by reaction between an aliphatic oxycarboxylic acid, an ester from polyhydric alcohol and aromatic polybasic acid (anhydride), and epsilon-caprolactone. CONSTITUTION:The objective low-shrinking agent consisting of a lactone polymer with a mol.wt. 1,000-10,000 prepared by reaction, catalysed by titanium compound, pref. in an inert gas atmosphere, between (I) 10-40wt% of (i) 50-90wt% of an aliphatic oxycarboxylic acid (pref. glycolic acid, oxycaproic acid plus (ii) 10-50wt% of an ester from polyhydric alcohol and aromatic polybasic acid (anhydride) and (II) 60-90wt% of epsilon-caprolactone. The other objective composition can be obtained by incorporating (A) 100pts.wt. of a blend of (1) 30-80pts.wt of an unsaturated polyester resin and (2) 70-20pts.wt of an ethylenic unsaturated monomer (e.g. styrene) with (B) 5-200pts.wt of said low-shrinking agent and (C) inorganic filler, reinforcer, and polymerization initiator. |
