| 摘要 |
<p>PROBLEM TO BE SOLVED: To obtain an aromatic polycarbodiimide having a low water absorptivity and ready solubility in an organic solvent and being excellent in heat resistance, etc., by selecting an aromatic polycarbodiimide having no polar group in the molecule. SOLUTION: This polycarbodiimide has structural units of formula I (wherein n is 2-300; R is an organic group, desirably, a 3-20C alkyl or a fluoroalkyl). It can be produced, for example, by polymerizing a diisocyanate of formula II alone or in combination with another diisocyanate (e.g. 4,4'-diphenylmethane diisocyanate) within the scope not detrimental to the properties of the polycarbodiimide at 40-150 deg.C in the presence of a phosphorus catalyst. The polycarbodiimide is excellent also in humidity resistance and low permittivity characteristics, and especially, a polycarbodiimide having long-chain alkyl ether groups or long-chain fluoroalkyl ether groups as side chains has a low modulus and excellent adhesiveness and can be used as e.g. a heat-resistant coating material in a soldering step in the production of electronic components.</p> |
