申请人:Daicel Chemical Industries, Ltd.
公开号:EP0943626A1
公开(公告)日:1999-09-22
Using the dope containing the following cellulose acetate (1), (2), or (3), a film is prepared by the casting process:
(1) a cellulose acetate having carboxyl groups binding to at least one member selected from the group consisting of a cellulose acetate and a hemicellulose acetate, wherein at least a part of said carboxyl groups are in an acidic form;
(2) a cellulose acetate containing at least one member selected from the group consisiting of an acid having an acid dissociation exponent pKa of 1.93 to 4.50 in water, an alkali metal salt of said acid and an alkaline earth metal of said acid; or
(3) a cellulose acetate containing an alkali metal or an alkaline earth metal wherein the total content of an alkaline metal and an alkaline earth metal in 1 gram of the cellulose acetate is from an effective amount to 5.5 x 10-6 equivalent (in terms of ion equivalent). The above cellulose acetate is also useful for spinning process. The cellulose acetate includes a cellulose diacetate and a cellulose triacetate. The cellulose acetate of the present invention has high film-releasability from a support and excellent optical characteristics.
使用含有以下醋酸纤维素 (1)、(2) 或 (3) 的涂料,通过浇铸工艺制备薄膜:
(1) 具有羧基的醋酸纤维素,羧基与至少一个选自醋酸纤维素和醋酸半纤维素的成员结合,其中至少一部分羧基呈酸性;
(2) 含有至少一个成员的醋酸纤维素,该成员选自由在水中的酸解离指数 pKa 为 1.93 至 4.50 的酸、所述酸的碱金属盐和所述酸的碱土金属组成的组;或
(3) 含有碱金属或碱土金属的醋酸纤维素,其中 1 克醋酸纤维素中碱金属和碱土金属的总含量为有效量至 5.5 x 10-6 当量(以离子当量计)。上述醋酸纤维素还可用于纺丝工艺。醋酸纤维素包括二醋酸纤维素和三醋酸纤维素。本发明的醋酸纤维素具有很高的从载体中释放薄膜的能力和优异的光学特性。