| 摘要 |
PURPOSE:To obtain the titled polymer particles suitable as a paper filler and giving a good yield in paper-making, by reacting a urea/formaldehyde precondensate with an aqueous acid solution in the presence of glycolic acid (salt) and a protective colloid. CONSTITUTION:1mol of urea is reacted with about 1-2.5mol of formaldehyde at a temperature of about 40-100 deg.C to produce a urea/formaldehyde precondensate. This precondensate is reacted with an aqueous acid solution (e.g., aqueous sulfuric or hydrochloric acid solution) in the presence of glycolic acid or its salt (e.g., sodium or potassium glycolate) and a protective colloid (e.g., carboxymethylcellulose or starch). The formed coagulum is slurried by dispersing with agitation, neutralized with an alkali and washed with water to obtain the purpose crosslinked urea/formaldehyde polymer particles.
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