A modified conjugated diene-based polymer represented by Formula 1, wherein a terminal of a polymer chain is modified, and a method for preparing same are provided. By including a modifier derived unit having a specific structure, a beta value affecting cold flow may be reduced through controlling the degree of branch, and accordingly, the cold flow of a polymer may be efficiently controlled and a mooney viscosity increasing ratio may be improved.

A modified conjugated diene-based polymer represented by Formula 1, wherein a terminal of a polymer chain is modified, and a method for preparing same are provided. By including a modifier derived unit having a specific structure, a beta value affecting cold flow may be reduced through controlling the degree of branch, and accordingly, the cold flow of a polymer may be efficiently controlled and a mooney viscosity increasing ratio may be improved.

Disclosed is a method of preparing a vinyl cyanide compound-conjugated diene rubber-aromatic vinyl compound graft copolymer, a method of preparing a thermoplastic resin composition including the same, and a thermoplastic resin composition including the same. More specifically, when a conjugated diene compound and a molecular weight regulator are fed in a split manner during polymerization of conjugated diene rubber, and the content of an emulsifier is reduced, gel content may be reduced. In addition, when enlarged conjugated diene-based rubber latex is prepared by enlarging conjugated diene-based rubber latex using an acid enlarging agent, the enlarged conjugated diene-based rubber latex may have an expanded full width at half maximum in particle size distribution, thereby improving gloss, reflection haze, fluidity, and impact resistance. In addition, deposits may be reduced during injection molding.

Disclosed is a method of preparing a vinyl cyanide compound-conjugated diene rubber-aromatic vinyl compound graft copolymer, a method of preparing a thermoplastic resin composition including the same, and a thermoplastic resin composition including the same. More specifically, when a conjugated diene compound and a molecular weight regulator are fed in a split manner during polymerization of conjugated diene rubber, and the content of an emulsifier is reduced, gel content may be reduced. In addition, when enlarged conjugated diene-based rubber latex is prepared by enlarging conjugated diene-based rubber latex using an acid enlarging agent, the enlarged conjugated diene-based rubber latex may have an expanded full width at half maximum in particle size distribution, thereby improving gloss, reflection haze, fluidity, and impact resistance. In addition, deposits may be reduced during injection molding.

An object of the present disclosure is to provide a rubber composition from which a crosslinked rubber molded product having good softness and excellent resilience performance can be obtained. The present disclosure provides a rubber composition containing (a) a base rubber, (b) a co-crosslinking agent, (c) a crosslinking initiator, and (d) a salt of a benzothiazole derivative, wherein (d) the salt of the benzothiazole derivative includes a compound represented by the formula (1) in which a sulfur atom S.sup.2 constituting a thiocarbonyl group has a Mulliken charge of −0.190 or more.

##STR00001##

[In the formula (1), R.sup.1 to R.sup.4 are identical to or different from each other, and represent an electron-withdrawing group or a hydrogen atom, S.sup.1 and S.sup.2 represent a sulfur atom, X represents a cation component, n is an integer ranging from 1 to 4, and at least one of R.sup.1 to R.sup.4 bonding to the identical benzene ring is an electron-withdrawing group when n is 2 or more.]

An object of the present disclosure is to provide a rubber composition from which a crosslinked rubber molded product having good softness and excellent resilience performance can be obtained. The present disclosure provides a rubber composition containing (a) a base rubber, (b) a co-crosslinking agent, (c) a crosslinking initiator, and (d) a salt of a benzothiazole derivative, wherein (d) the salt of the benzothiazole derivative includes a compound represented by the formula (1) in which a sulfur atom S.sup.2 constituting a thiocarbonyl group has a Mulliken charge of −0.190 or more.

##STR00001##

[In the formula (1), R.sup.1 to R.sup.4 are identical to or different from each other, and represent an electron-withdrawing group or a hydrogen atom, S.sup.1 and S.sup.2 represent a sulfur atom, X represents a cation component, n is an integer ranging from 1 to 4, and at least one of R.sup.1 to R.sup.4 bonding to the identical benzene ring is an electron-withdrawing group when n is 2 or more.]

Compounds are based on polyether-modified polybutadiene, where the polyether-modified polybutadiene contains repeat units selected from the divalent radicals:

##STR00001##

The radical B has at least one ester group.

Compounds are based on polyether-modified polybutadiene, where the polyether-modified polybutadiene contains repeat units selected from the divalent radicals:

##STR00001##

The radical B has at least one ester group.

A rubber composition of the present invention contains 100 parts by mass of a rubber component (A) containing 45 to 75% by mass of natural rubber and 25 to 55% by mass of a conjugated diene-based polymer, in which a bonded styrene amount of the conjugated diene compound moieties is 25% or less, 1 to 40 parts by mass of a non-modified conjugated diene-based polymer (B) which has a weight average molecular weight of 5,000 or more but less than 40,000 in terms of polystyrene as measured by GPC and in which a bonded styrene amount of the conjugated diene compound moieties is less than 10% and a bonded vinyl amount of the conjugated diene compound moieties is 20% or more, and a filler (C), in which at least one of the conjugated diene-based polymers contained in the rubber component (A) is a modified conjugated diene-based polymer. With the rubber composition, a tire having further enhanced on-ice performance and having both excellent on-ice performance and excellent abrasion resistance is obtained.

A rubber composition of the present invention contains 100 parts by mass of a rubber component (A) containing 45 to 75% by mass of natural rubber and 25 to 55% by mass of a conjugated diene-based polymer, in which a bonded styrene amount of the conjugated diene compound moieties is 25% or less, 1 to 40 parts by mass of a non-modified conjugated diene-based polymer (B) which has a weight average molecular weight of 5,000 or more but less than 40,000 in terms of polystyrene as measured by GPC and in which a bonded styrene amount of the conjugated diene compound moieties is less than 10% and a bonded vinyl amount of the conjugated diene compound moieties is 20% or more, and a filler (C), in which at least one of the conjugated diene-based polymers contained in the rubber component (A) is a modified conjugated diene-based polymer. With the rubber composition, a tire having further enhanced on-ice performance and having both excellent on-ice performance and excellent abrasion resistance is obtained.