Abstract: In a state where a shoulder member is in contact with a contact surface, a pin member is brought into contact with the contact surface to specify a pin movement amount, which is a distance from an initial position of the pin member to the contact surface, and specify a shoulder displacement amount, which is a displacement amount when the shoulder member is retreated as a result of the contact of the pin member. When both a first condition that the pin movement amount is included in a first range and a second condition that the shoulder displacement amount is included in a second range are satisfied, the pin member is retreated from the contact surface by a predetermined return amount, and furthermore, origin point alignment of the pin member and the shoulder member is performed on the basis of positions of the pin member and the shoulder member.

Abstract: In a process for the microsuspension of emulsion polymerization of vinyl chloride using a polymerization apparatus equipped with an agitator the improvement where the ratio (H/D) of the effective height (H) of the apparatus to the effective inner diameter (D) of the apparatus is 4 or more.

Abstract: In a process for the microsuspension or emulsion polymerization of vinyl chloride using a polymerization apparatus equipped with an agitator the improvement where the ratio (H/D) of the effective height (H) of the apparatus to the effective inner diameter (D) of the apparatus is 4 or more.

Abstract: Polymer scale deposition on polymerization reactor inside surfaces in the polymerization of a monomer or monomers having an ethylenic double bond and/or a monomer or monomers having diolefinic double bonds is prevented, peelability or removability of polymer scales deposited on such surface, if any, is improved and the scale inhibitor adherence to the wall surface of glass-lined polymerization reactors is improved by coating the inside surfaces of the reactor in advance with a coating composition comprising a quinone-amine compound having a molecular weight of at least 3,000 as obtained by subjecting at least one aromatic diamine and at least one aromatic quinone to addition reaction in at least one solvent having a solubility parameter of 8.5 to 24.0 and/or a reduced form of said quinone-amine compound and at least one silica organosol or a mixture of at least one silica organosol and at least one alkyl silicate to thereby form a hydrophilic coat film on the surfaces.