| 摘要 |
PROBLEM TO BE SOLVED: To obtain the subject resin having excellent solder heat resistance and peeling strength and capable of coping with high-solidification of an adhesive while having low viscosity by subjecting polyvinyl alcohol and an aldehyde to acetalization reaction and specifying the polymerization degree, the content of acetyl group, the content of acetalized part, or the like. SOLUTION: This polyacetal resin having a polymerization degree within the range of 1,000-2,500, 5-20 mol% of acetyl group content, 20-30 mol% of hydroxyl group content and >=70 mol% of acetalized part by acetaldehyde based on the whole acetalized part and the content of carboxyl group bonded as a side chain within a range of 0.1-5 mol% is obtained by acetalizing (A) polyvinyl alcohol with (B) an aldehyde. Preferably, the total content of alkaline metal and alkaline earth metal as impurities is <=100 ppm and the content of an anion is <=100 ppm in the objective resin.
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