Sealing member and method for manufacturing the same

A method for manufacturing a sealing member, the method comprising:

• forming a coating layer by impregnating a substrate with a hydrolyzed solution of an organosilicon compound, followed by drying,
• wherein the sealing member includes:
• a substrate including a polytetrafluoroethylene matrix having a porous structure with pores that contain alumina particles therein;
• a coating layer on the surface of the substrate, the coating layer being made of a condensate of the organosilicon compound,
• the organosilicon compound is represented by the following formula:
• R1—Si—(R2)3,
• wherein in the formula, R1 represents an alkyl group with 1 to 5 carbon atoms, and each R2 independently represents a halogen atom or an alkoxy group with 1 to 4 carbon atoms, and
• the condensate of the organosilicon compound is present in the pores of the polytetrafluoroethylene matrix.

A method for producing a polymer by polymerizing at least one polymerizable monomer, the method comprising:

• transferring the polymerizable monomer into a polymerization container through a transferring path, the transferring path including a plurality of pipes connected together with a connection between the pipes sealed with a sealing member,
• wherein the sealing member includes:
• a substrate including a polytetrafluoroethylene matrix having a porous structure with pores that contain alumina particles;
• a coating layer on the surface of the substrate, the coating layer being made of a condensate of an organosilicon compound,
• the organosilicon compound is represented by the following formula:
• R1—Si—(R2)3,
• wherein in the formula, R1 represents an alkyl group with 1 to 5 carbon atoms, and each R2 independently represents a halogen atom or an alkoxy group with 1 to 4 carbon atoms, and
• the condensate of the organosilicon compound is present in the pores of the polytetrafluoroethylene matrix.