申请人:Denki Kagaku Kogyo Kabushiki Kaisha
公开号:EP2083039A1
公开(公告)日:2009-07-29
Provided are a polyvinyl acetal sheet which is excellent in adhesion to glass, easy in control of adhesion, little colored, highly transparent and excellent in penetration resistance even under high-temperature conditions when the sheet is used for laminated glass or the like, a process for its production and a process for producing polyvinyl acetal particles used for the sheet.
The polyvinyl acetal sheet is produced by molding polyvinyl acetal particles into a sheet with a degree of acetalization of from 75.0 to 84.0 mass% and with a porosity of from 60 to 85%. The polyvinyl acetal particles are preferably produced by an acetalization reaction of 100 parts by mass of a polyvinyl alcohol and from 40 to 75 parts by mass of an aldehyde in the presence of an acid catalyst at a reaction temperature of from 20 to 60°C, and the acetalization reaction comprises supplying the polyvinyl alcohol, the aldehyde and the acid catalyst to a reactor to bring about acetalization, discharging a reaction mixture from the reactor after the degree of acetalization of the produced polyvinyl acetal has reached 13 mass%, and subjecting the discharged reaction mixture to an aging reaction.
本发明提供了一种聚乙烯醇缩醛片材,该片材与玻璃的粘合力极佳,易于控制粘合力,着色少,透明度高,即使在高温条件下用于夹层玻璃或类似材料时也具有极佳的抗渗透性;还提供了一种生产该片材的工艺和一种生产用于该片材的聚乙烯醇缩醛颗粒的工艺。
聚乙烯醇缩醛板是通过将聚乙烯醇缩醛颗粒模塑成缩醛度为 75.0 至 84.0 质量%、孔隙率为 60 至 85%的板材而制成的。聚乙烯醇缩醛颗粒最好是由 100 质量份的聚乙烯醇和 40 至 75 质量份的醛在酸催化剂存在下,在 20 至 60°C 的反应温度下进行缩醛反应制得,缩醛反应包括提供聚乙烯醇、醛和催化剂、在生产的聚乙烯醇缩醛的缩醛度达到 13 质量%后,将反应混合物从反应器中排出,并将排出的反应混合物进行老化反应。