A method for producing a vinyl chloride-based polymer, wherein the vinyl chloride-based polymer is produced by sequentially adding a first emulsifier and a second emulsifier, which are different from each other, during polymerization and using a succinate compound as a first emulsifier. The method provides improved processability by achieving low-viscosity properties when plastisol is mixed using the produced polymer, and improved fogging properties by suppressing generation of volatile organic compounds.

A method of producing a fluorine-containing compound is a method of producing a compound (30) having partial structure (3) by an insertion reaction of compound (20) into compound (10) that has partial structure (1), in the presence of an ionic catalyst formed from a specific monovalent anion and a counter cation. In the formulas, * represents a bonding site, and X.sup.1 and R.sup.1 to R.sup.4 each independently represents a hydrogen atom, a fluorine atom, a chlorine atom, or an organic group having a carbon number of 1 to 20 which may have a substituent.

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A method for producing a vinyl polymer by suspension-polymerizing a vinyl compound in the presence of a dispersion stabilizer, wherein the dispersion stabilizer contains a polyvinyl alcohol and a composition containing a modified polyvinyl alcohol and a compound; the modified polyvinyl alcohol contains double bonds derived from an unsaturated carboxylic acid or a derivative thereof in side chains; the compound is a compound having two or more hydroxy groups bonded to a conjugated double bond; the modified polyvinyl alcohol has a saponification degree and a viscosity-average polymerization degree different from those of the polyvinyl alcohol; a content of the compound in the composition is 0.001 parts by mass or more and less than 5 parts by mass based on 100 parts by mass of the modified polyvinyl alcohol; and a mass ratio of the composition to the polyvinyl alcohol is 50/50 to 90/10.

A method for producing a vinyl polymer by suspension-polymerizing a vinyl compound in the presence of a dispersion stabilizer, wherein the dispersion stabilizer contains a polyvinyl alcohol and a composition containing a modified polyvinyl alcohol and a compound; the modified polyvinyl alcohol contains double bonds derived from an unsaturated carboxylic acid or a derivative thereof in side chains; the compound is a compound having two or more hydroxy groups bonded to a conjugated double bond; the modified polyvinyl alcohol has a saponification degree and a viscosity-average polymerization degree different from those of the polyvinyl alcohol; a content of the compound in the composition is 0.001 parts by mass or more and less than 5 parts by mass based on 100 parts by mass of the modified polyvinyl alcohol; and a mass ratio of the composition to the polyvinyl alcohol is 50/50 to 90/10.

The present invention provides a chlorinated polyvinyl chloride that enables excellent continuous productivity in molding and that enables a molded article to have both processability and unevenness-preventing properties. Provided is a chlorinated polyvinyl chloride having an endothermic peak start temperature (L) and an endothermic peak end temperature (H) that satisfy the following expression (1) in endothermic peak measurement using a differential scanning calorimeter (DSC): 41° C.≤H−L≤98° C. (1).

The present invention provides a chlorinated polyvinyl chloride that enables excellent continuous productivity in molding and that enables a molded article to have both processability and unevenness-preventing properties. Provided is a chlorinated polyvinyl chloride having an endothermic peak start temperature (L) and an endothermic peak end temperature (H) that satisfy the following expression (1) in endothermic peak measurement using a differential scanning calorimeter (DSC): 41° C.≤H−L≤98° C. (1).

The present invention provides a chlorinated polyvinyl chloride that enables excellent continuous productivity in molding and that enables a molded article to have both processability and unevenness-preventing properties. Provided is a chlorinated polyvinyl chloride having an endothermic peak start temperature (L) and an endothermic peak end temperature (H) that satisfy the following expression (1) in endothermic peak measurement using a differential scanning calorimeter (DSC): 41° C.≤H−L≤98° C. (1).

The present invention provides a resin composition for molding capable of producing a molded article that has excellent heat distortion resistance, excellent mechanical properties, high impact resistance, and high transparency and has a smaller change in weight at high temperature. The present invention also provides a molded article and a joint each produced from the resin composition for molding. Provided is a resin composition for molding, including: a chlorinated polyvinyl chloride resin; a polyvinyl chloride; and a thermal stabilizer, the chlorinated polyvinyl chloride resin containing structural units (a) to (c) represented by the following formulas (a) to (c) in proportions of 5 to 90 mol % of the structural unit (a), 5 to 40 mol % of the structural unit (b), and 5 to 55 mol % of the structural unit (c) based on a total number of moles of the structural units (a), (b), and (c), the polyvinyl chloride being contained in an amount of 1 to 30 parts by mass based on 100 parts by mass of the chlorinated polyvinyl chloride resin,

[Chem. 1]

—CH.sub.2—CHC1-  (a)

—CH.sub.2—CC1.sub.2-  (b)

—CHC1-CHC1-  (c).

The present invention provides a resin composition for molding capable of producing a molded article that has excellent heat distortion resistance, excellent mechanical properties, high impact resistance, and high transparency and has a smaller change in weight at high temperature. The present invention also provides a molded article and a joint each produced from the resin composition for molding. Provided is a resin composition for molding, including: a chlorinated polyvinyl chloride resin; a polyvinyl chloride; and a thermal stabilizer, the chlorinated polyvinyl chloride resin containing structural units (a) to (c) represented by the following formulas (a) to (c) in proportions of 5 to 90 mol % of the structural unit (a), 5 to 40 mol % of the structural unit (b), and 5 to 55 mol % of the structural unit (c) based on a total number of moles of the structural units (a), (b), and (c), the polyvinyl chloride being contained in an amount of 1 to 30 parts by mass based on 100 parts by mass of the chlorinated polyvinyl chloride resin,

[Chem. 1]

—CH.sub.2—CHC1-  (a)

—CH.sub.2—CC1.sub.2-  (b)

—CHC1-CHC1-  (c).

Provided is a dispersion assistant useful for suspension polymerization of vinyl-based compounds. The dispersion assistant comprises a polyvinyl alcohol-based polymer (A) comprising a constituent unit represented by the general formula (1) shown below at 0.1 to 10 mol % per polyvinyl alcohol monomer unit and having a saponification degree of 15 to 70 mol %. ##STR00001##
(In the formula, R denotes an alkyl group.)