| 摘要 |
PURPOSE:To obtain a laminate which is excellent in silver migration resistance by using a paper base material wherein a swelling rate of a paper fiber by water absorption is controlled to a specific value or under by impregnating the paper base material with resin to its fiber inside when the paper base material is primarily processed with water soluble varnish. CONSTITUTION:A main component of a paper fiber is a cellulose having a great amount of an alcoholic hydroxyl group. The alcoholic hydroxyl group adsorbs a polar solvent molecule. At last the paper fiber is impregnated with the polar solvent molecule to its inside, and the paper fiber itself is swollen. Thereby, a combination of polar solvent and water soluble thermosetting resin which is suitable for the primary processing varnish is selected to be added, or a cationic seed having an impregnation accelerating effect is added into the varnish. The paper fiber is impregnated with the resin to its inside thereby, and the swelling rate by water absorption of the paper fiber is made under 10%. Therefore, silver migration resistance of a molded laminate can be extremely improved. |
