| 摘要 |
PURPOSE: To obtain a solder mask coating film having covering ability and flexibility by incorporating a UV-hardening compd., a photoinitiator therefor, a free radical initiator which is activated by heat, and a poly unsatd. compd. which can be thermally crosslinked with free radicals. CONSTITUTION: This compsn. contains a UV-hardening compd., a thermally crosslinking poly unsatd. compd. by 5 to 30%, at least one kind of reactive monomer diluent by 4 to 60%, and a photoinitiator by 0.5 to 10%, and a free radical thermal initiator by 0.2 to 5%. The UV-hardening compd. contains 10 to 50% urethane acrylate having acid functional groups, 5 to 40% aromatic urethane diacrylate, and 2 to 30% aliphatic or alicyclic urethane diacrylate or the mixture of these. Thereby, desirable flexibility, developing property with alkali water, adhesive property, surface hardness and high hardening depth with a low energy level can be obtd. The thermally crosslinking hardening compd. shows good covering property. |
