| 摘要 |
<p>PURPOSE:To provide an ink for screen printing consisting of a solvent-insoluble thermoplastic polymer in powder state, a polyimide precursor and a solvent, having heat resistance and good screen printing property and showing a reduced shrinkage stress in curing. CONSTITUTION:The ink is prepared by mixing (1) solvent-insoluble thermoplastic polymer in powder state, (2) a polyimide precursor and (3) a solvent. Polymer (1) has a melting point of 100-350 deg.C and a number-average particle diameter of 50mu or smaller. When the particle diameter exceeds 50mu, the ink forms a film with a rough surface and has a poor form retention for patterns and good prints are unobtainable. ''solvent-insoluble'' means that the polymer is insoluble in the solvent used in practice. Polymer (1) is used in an amount of 15-40% of the solvent. When it is used in less than 15%, the powder content of the ink is too low to obtain good printability, while when it exceeds 40%, uniform dispersion of the powder becomes difficult.</p> |
