Silane crosslinkable silicone rubber composition, silane crosslinked silicone rubber formed body, method of producing same, and silane crosslinked silicone rubber formed article

A method of producing a silane crosslinkable silicone rubber composition, including a step (1) of obtaining a silane crosslinkable silicone rubber composition by mixing a millable silicone rubber, and with respect to 100 parts by mass of the base rubber containing a millable silicone rubber, 1 to 15 parts by mass of a silane coupling agent having a grafting reaction site capable of being graft-reacted with the base rubber, 0.5 to 300 parts by mass of an inorganic filler, 0.01 to 0.6 parts by mass of an organic peroxide, and 0.01 to 0.5 parts by mass of a silanol condensation catalyst,

• 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):
• Step (a):
• a step of preparing a silane masterbatch by melt-mixing all or a part of the base rubber, the silane coupling agent, the inorganic filler, and the organic peroxide at a temperature equal to or higher than a decomposition temperature of the 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 mixing the silane masterbatch with the silanol condensation catalyst or the catalyst masterbatch.

A method of producing a silane crosslinked silicone rubber formed body, including the following step (1), step (2), and step (3):

• Step (1):
• a step of obtaining the silane crosslinkable silicone rubber composition by mixing a base rubber containing a millable silicone rubber, and with respect to 100 parts by mass of the base rubber containing a millable silicone rubber, 1 to 15 parts by mass of a silane coupling agent having a grafting reaction site capable of being graft-reacted with the base rubber, 0.5 to 300 parts by mass of an inorganic filler, 0.01 to 0.6 parts by mass of an organic peroxide, and 0.01 to 0.5 parts by mass of a silanol condensation catalyst,
• Step (2):
• a step of obtaining a formed body by forming the silane crosslinkable silicone rubber composition, and
• Step (3):
• a step of obtaining the silane crosslinked silicone rubber 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):
• Step (a):
• a step of preparing a silane masterbatch by melt-mixing all or a part of the base rubber, the silane coupling agent, the inorganic filler, and the organic peroxide at a temperature equal to or higher than a decomposition temperature of the 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 mixing the silane masterbatch with the silanol condensation catalyst or the catalyst masterbatch.