Electroless Plating of Plastics Activated with Mixed Hydroxide Colloids

研究了混合氢氧化物胶体活化法在各种塑料表面化学镀Cu、Ni、Co及Ni-Co合金的适用性。（1）SiO_2、ZrO_2、CuO、NiO、Cu（OH）_2和Ni（OH）_2的等电点分别为3.35，4.6，6.0，7.7，7.8和8.7。此外，在本工作中使用的塑料被发现是负电荷。(2)氢氧化物胶体在ABS塑料上的吸附受胶体溶液温度的影响，表明其活化过程为化学吸附。(3)用Ni（OH）_2-Cu（OH）_2胶体聚集体对ABS、PP、PE、PS、PC、PVC等塑料进行了化学镀铜活化处理。该活化方法也适用于ABS塑料表面化学镀Ni、Co及Ni-Co合金。(4)在ABS塑料表面形成的Cu或Ni膜的附着强度和光亮度与传统的SnCl_2-PdCl_2活化法相当。(5)用Na_2CO_3溶液制备的混合胶体活化的ABS塑料表面铜膜的光亮度和附着力均优于用NaOH溶液制备的混合胶体。(6)铜电极对甲醛溶液阳极氧化的催化作用大于镍电极。(7)用表面电化学方法可以解释塑料活化过程的机理。

The applicability of a method of acivation using mixed hydroxide colloids was studied for the electroless plating of Cu, Ni, Co and Ni-Co alloy onto various plastics. Furthermore, zeta-potentials were measured for various oxides to understand the mechanism of the activation process.The main results were as followed :(1) The isoelectric points Of SiO_2, ZrO_2, CuO, NiO, Cu(OH)_2 and Ni(OH)_2 were found to be 3.35, 4.6, 6.0, 7.7, 7.8 and 8.7 respectively. Also the plastics used in the present work were found to be charged negatively.(2) The adsorbtion of hydroxide colloid onto ABS plastic is infl enced by the temperature of the colloidal solution, suggesting the activation process is chemical adsorbtion.(3) The plastics, including ABS, PP, PE, PS, PC, PVC were satisfactorily activated with colloid aggregates of Ni(OH)_2-Cu(OH)_2 for electroless plating of copper. This activation method was also found to be applicable to the electroless plating of Ni, Co and Ni-Co alloy on ABS plastics.(4) The adhesion strength and brightness of Cu or Ni films formed on the ABS plastic were amply competitive with those activated by a conventiona SnCl_2-PdCl_2 method.(5) The copper films formed on ABS plastic, activated with mixed colloids prepared with Na_2CO_3 solution were good in brightness and adhesion force compared with those activated with mixed colloids the prepared with NAOH solution.(6) The catalytic effect of copper electrode for the anodic oxidation of HCHO solution was found to be large compared with that of Ni electrode.(7) The mechanism of the process of activation of plastics can be explaned by surface electrochemistry.