申请人:MITSUBISHI RAYON CO., LTD.
公开号:EP0273390A2
公开(公告)日:1988-07-06
Disclosed is a radiation curable resin composition permitting good dispersion of magnetic powders and forming a highly durable cured film, and hence suitable for use in the formation of magnetic recording media. This resin composition consists essentially of a urethane (meth)acrylate obtained by the reaction of
(A) a hydroxyl-containing compound (I) composed of an amido hydroxy compound (a₁) having at least one amido group and at least one isocyanate-reactive hydroxyl group in the molecule, and at least one polyol compound (a₂) selected from polyester polyols, polyether polyols and alkyl polyols, the number of moles (x₁) of the hydroxyl groups present in the amido hydroxy compound (a₁) being from 5 to 80% of the total number of moles of the hydroxyl groups contained in component (A) and the number of moles (x₂) of the hydroxyl groups present in the polyol compound (a₂) being from 95 to 20% of the total number of moles of the hydroxyl groups contained in component (A);
(B) a polyisocyanate compound having two or more isocyanate groups in the molecule;
(C) a phosphoric ester of the general formula
where R is hydrogen or methyl, A is a divalent alcohol residue, Rʹ is hydrogen or an alkyl group of 1 to 4 carbon atoms, and m is 1 or 2; and
(D) a hydroxyl-containing alkyl (meth)acrylate other than component (C),
the urethane (meth)acrylate being further characterized in that, when the number of moles of the hydroxyl groups present in component (A) is represented by X and the number of moles of the isocyanate groups present in component (B) is represented by Y, the ratio of X to Y ranges from 1:1.1 to 1:2, the number of moles (Z) of the hydroxyl groups present in components (C) and (D) is not less than (Y-X), and the number of moles of component (C) is between 0.1 (Y-X) and 0.7 (Y-X), both inclusive.
本发明公开了一种可辐射固化的树脂组合物,它能很好地分散磁性粉末,并能形成非常耐久的固化膜,因此适用于磁性记录介质的形成。这种树脂组合物主要由聚氨酯(甲基)丙烯酸酯组成,这种聚氨酯(甲基)丙烯酸酯是通过以下反应获得的
(A) 含羟基化合物 (I),由分子中含有至少一个氨基和至少一个异氰酸酯反应性羟基的氨基羟基化合物 (a₁) 和至少一种多元醇化合物 (a₂) 组成,多元醇化合物 (a₂) 选自聚酯多元醇、聚醚多元醇和烷基多元醇、存在于氨基羟基化合物(a₁)中的羟基摩尔数(x₁)为组分(A)中所含羟基总摩尔数的 5%至 80%,存在于多元醇化合物(a₂)中的羟基摩尔数(x₂)为组分(A)中所含羟基总摩尔数的 95%至 20%;
(B) 分子中含有两个或两个以上异氰酸酯基团的多异氰酸酯化合物;
(C) 通式如下的磷酸酯
其中 R 是氢或甲基,A 是二价醇残基,Rʹ 是氢或 1 至 4 个碳原子的烷基,m 是 1 或 2;以及
(D) 成分 (C) 以外的含羟基的烷基(甲基)丙烯酸酯、
该聚氨酯(甲基)丙烯酸酯的进一步特征在于,当存在于组分(A)中的羟基的摩尔数用 X 表示,而存在于组分(B)中的异氰酸酯基团的摩尔数用 Y 表示时,X 与 Y 的比例范围为 1:1.1至1:2,存在于组分(C)和(D)中的羟基的摩尔数(Z)不小于(Y-X),组分(C)的摩尔数在0.1(Y-X)至0.7(Y-X)之间,均包括在内。