| abstract |
(57) [Summary] [Structure] A butadiene-based resin having a polymerizable ethylenically unsaturated double bond at a molecular end and / or a side chain is used as an oligomer component, and the main chain skeleton of the butadiene-based resin is a butadiene homopolymer. And a photocurable resin composition using a butadiene-based resin having a structure in which the bonding state of butadiene chains is 1,4-bond in the skeleton of 50% or more. [Effect] Since the amount of gas volatilized from the cured product is extremely low, It is most suitable as a sealing material for electrical and electronic parts that have been hitherto adversely affected by corrosion and malfunction due to volatilized gas from a hardened material. Especially, by using it as a sealing material provided on the mating surface of the housing of a magnetic hard disk drive, a recording medium It is possible to prevent corrosion, malfunction, dust intrusion, etc., and improve the reliability of the magnetic hard disk drive. |