Method for preparing a hydrophilic composition containing a matting agent, and photographic materials comprising a layer containing this composition
申请人:AGFA-GEVAERT
naamloze vennootschap
公开号:EP0003627A1
公开(公告)日:1979-08-22
Method for preparing a hydrophilic composition containing a matting agent, and photographic materials comprising a layer containing this composition.
Hydrophilic coating compositions are made comprising a protective colloid and dispersed therein a matting agent. The matting agent is obtained by mixing in aqueous medium urea, formaldehyde and an aqueous colloidal dispersion of silica. The mixture is buffered to keep the pH at 3.2 or lower. Urea and formaldehyde are polycondensed whilst vigorously stirring until particles comprising urea-formaldehyde resin and silica are formed of average particle size of 1-8 µm. The rate of stirring is reduced and the pH is raised to 5 or higher to prevent afterpolycondensation and agglomeration of the polymer particles. A hydrophilic colloid is then dissolved in the reaction mixture. Photographic light-sensitive silver halide material incorporating a layer formed from the hydrophilic coating composition.
制备含有消光剂的亲水涂层组合物的方法,以及含有该组合物涂层的照相材料。
亲水涂层组合物由保护胶体和分散在其中的消光剂组成。消光剂是通过在水性介质中混合尿素、甲醛和二氧化硅的水性胶体分散体而得到的。混合物经过缓冲,pH 值保持在 3.2 或更低。尿素和甲醛在剧烈搅拌下缩聚,直至形成平均粒径为 1-8 微米的由脲醛树脂和二氧化硅组成的颗粒。搅拌速度降低,pH 值升至 5 或更高,以防止聚合物颗粒的缩聚和结块。然后在反应混合物中溶解亲水性胶体。光敏卤化银材料中含有亲水涂层组合物形成的层。