To provide a rubber composition in which wet performance, wear resistance, low rolling resistance, and breaking resistance are highly balanced. A rubber composition comprising a rubber component comprising at least three polymers and a filler, wherein the rubber component is separated into at least two polymer phases: a polymer phase (1) with the highest tan δ peak temperature; and a polymer phase (2) with the lowest peak temperature; the polymer phases (1) and (2) are incompatible with each other; the polymer phase (1) at least comprises the modified conjugated diene-based polymers (A1) and (A2), and the filler; the modified conjugated diene-based polymer (A1) has a particular weight-average molecular weight and a particular contracting factor (g′); and when a filler concentration and an average aggregate area of the filler in the polymer phase (1) are defined as X and Y, respectively, an formula (1): Y<4.8X+1200 is satisfied.

To provide a rubber composition in which wet performance, wear resistance, low rolling resistance, and breaking resistance are highly balanced. A rubber composition comprising a rubber component comprising at least three polymers and a filler, wherein the rubber component is separated into at least two polymer phases: a polymer phase (1) with the highest tan δ peak temperature; and a polymer phase (2) with the lowest peak temperature; the polymer phases (1) and (2) are incompatible with each other; the polymer phase (1) at least comprises the modified conjugated diene-based polymers (A1) and (A2), and the filler; the modified conjugated diene-based polymer (A1) has a particular weight-average molecular weight and a particular contracting factor (g′); and when a filler concentration and an average aggregate area of the filler in the polymer phase (1) are defined as X and Y, respectively, an formula (1): Y<4.8X+1200 is satisfied.

Provided is a liquid stabilizer, which can improve releasability without impairing transparency. A liquid stabilizer for a chlorine-containing resin of the present invention includes: an oxidized polyethylene wax having an acid value of 5 mgKOH/g or more; a dispersion medium; and at least one kind selected from the group consisting of a zinc salt, an alkaline earth metal salt, and an organotin compound. The liquid stabilizer of the present invention is a dispersion, and a dispersoid including the oxidized polyethylene wax has a median diameter (D.sub.50) of from 1 μm to 50 μm.

A rubber composition manufacturing method comprising an operation in which an intermeshing internal kneader is used to knead at least rubber, silica, and silane coupling agent, wherein the operation comprises a first step in which kneading which is accompanied by increase in kneading temperature is carried out during an initial phase of the operation; kneading is carried out during the first step while a ram is maintained in a state in which it is at a first position which is higher than a lowermost position within a range of movement of which the ram is capable; and during the first step, an effective volume when the ram is at the first position is 105% to 120% relative to a value of 100% for an effective volume when the ram is at the lowermost position.

A rubber composition manufacturing method comprising an operation in which an intermeshing internal kneader is used to knead at least rubber, silica, and silane coupling agent, wherein the operation comprises a first step in which kneading which is accompanied by increase in kneading temperature is carried out during an initial phase of the operation; kneading is carried out during the first step while a ram is maintained in a state in which it is at a first position which is higher than a lowermost position within a range of movement of which the ram is capable; and during the first step, an effective volume when the ram is at the first position is 105% to 120% relative to a value of 100% for an effective volume when the ram is at the lowermost position.

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).

A conjugated diene-based polymer of the present invention has an absolute molecular weight measured by viscosity detector-equipped GPC-light scattering measurement, of 40×10.sup.4 or more and 5000×10.sup.4 or less, has a branching number (Bn) measured by the viscosity detector-equipped GPC-light scattering measurement, of 8 or more, and has a modification ratio of 60% by mass or more.

A conjugated diene-based polymer of the present invention has an absolute molecular weight measured by viscosity detector-equipped GPC-light scattering measurement, of 40×10.sup.4 or more and 5000×10.sup.4 or less, has a branching number (Bn) measured by the viscosity detector-equipped GPC-light scattering measurement, of 8 or more, and has a modification ratio of 60% by mass or more.

The present invention relates to a method for manufacturing of partially fluorinated polymers, notably vinylidene fluoride (VDF)-based polymers, in emulsion polymerization, and to a polymer obtained from said method.