SEALING MATERIAL FOR ELECTROLYTIC CAPACITOR AND ELECTROLYTIC CAPACITOR EMPLOYING THE SEALING MATERIAL

摘要

A sealing material for electrolytic capacitors which has no fear of causing reversion due to crosslinking with an organic peroxide and can satisfy requirements including long-term heat resistance; and an electrolytic capacitor employing the sealing material. The sealing material is made of a modified butyl rubber composition obtained by reacting and modifying butyl rubber with a compound (a) which is stable at ordinary temperature even in the presence of oxygen and has a nitroxide free radical in the molecule, a radical initiator (b), and a radical-polymerizable monomer (c) having a functionality of 2 or higher and crosslinking the resultant modified butyl rubber composition with an organic peroxide. Alternatively, the sealing material is made of a modified butyl rubber composition obtained by reacting butyl rubber with a compound (a) which is stable at ordinary temperature even in the presence of oxygen and has a nitroxide free radical in the molecule and a radical initiator (b), incorporating a radical-polymerizable monomer (c) having a functionality of 2 or higher into the resultant modified butyl rubber composition, and crosslinking the mixture with an organic peroxide.