CPC C08L 27/16 (2013.01) [C08K 3/22 (2013.01); C08K 3/26 (2013.01); C08K 3/36 (2013.01); C08K 5/14 (2013.01); C08L 23/26 (2013.01); C08L 27/18 (2013.01); C08L 51/04 (2013.01); C08K 2003/2296 (2013.01); C08K 2003/265 (2013.01); C08L 2201/08 (2013.01); C08L 2203/206 (2013.01); C08L 2310/00 (2013.01); C08L 2312/08 (2013.01)] | 20 Claims |
1. A method of producing a heat-resistant crosslinked fluororubber formed body, including the following steps (1), (2) and (3):
Step (1): a step of obtaining a reaction composition containing a silane crosslinkable rubber by melt-mixing, with respect to 100 parts by mass of a base rubber containing 60 to 99% by mass of a fluororubber and 1 to 40% by mass of an ethylene-based copolymer resin modified with an unsaturated carboxylic acid, 0.003 to 0.5 parts by mass of an organic peroxide, 0.5 to 400 parts by mass of an inorganic filler, 2 to 15 parts by mass of a silane coupling agent having a grafting reaction site that is capable of being subjected to a grafting reaction with said base rubber in the presence of radicals generated from said organic peroxide, and a silanol condensation catalyst,
Step (2): a step of obtaining a formed body by forming the reaction composition, and
Step (3): a step of obtaining the heat-resistant crosslinked fluororubber formed body by bringing the formed body into contact with water,
wherein, when the step (1) is performed,
in a case of melt-mixing all of the base rubber in the following step (a), the step (1) includes the following step (a) and step (c), or in a case of melt-mixing a part of the base rubber in the following step (a), the step (1) includes the following step (a), step (b) and step (c), and
the ethylene-based copolymer resin modified with an unsaturated carboxylic acid is melt-mixed in at least one of the following steps (a) and (b):
Step (a): a step of preparing a silane masterbatch containing a silane crosslinkable rubber, by melt-mixing all or part of the base rubber, the organic peroxide, the inorganic filler and the silane coupling agent at a temperature equal to or higher than a decomposition temperature of said organic peroxide, and by graft-reacting the grafting reaction site and the base rubber due to radicals generated from said organic peroxide,
Step (b): a step of preparing a catalyst masterbatch, by melt-mixing a remainder of the base rubber, and the silanol condensation catalyst, and
Step (c): a step of obtaining the reaction composition, by melt-mixing the silane masterbatch and the silanol condensation catalyst or the catalyst masterbatch.
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