Production method for neutral papermaking sizing agent

摘要

PURPOSE: To obtain a rosinous diester excellent as a size for neutral papermaking by reacting a rosin with a dihydric alcohol and an α,β-unsaturated carbonyl compound successively or simultaneously, ;CONSTITUTION: A rosin (e.g. gum rosin) is prereacted with a dihydric alcohol (e.g. ethylene glycol) and an α,β-unsaturated carbonyl compound (e.g. maleic acid) successively or simultaneously at a temperature below the boiling point of the dihydric alcohol, usually 150-200°C, and further reacted at 225-280°C to obtain a size for neutral papermaking based on a rosinous diester containing a dicarboxylic acid (anhydride) group and represented by the formula (wherein R₁ is a residue of rosin acid or a residue of maleopimaric acid; R₂ is a residue of a dihydric alcohol; and R, is a residue of maleopimaric acid). The reaction product has 15-40wt.% of a component of a molecular weight of 290-315, 10-35wt.% of a component of a molecular weight of 390-420, 1-25wt.% of a component of a molecular weight of 580-660 and 20-50wt.% of a component of a molecular weight of 670-880.;COPYRIGHT: (C)1994,JPO&Japio