Nippon Zeon Company, Ltd.

Kohkichi Noguchi

Hiroyuki Watanabe

Shuichi Akita

Toshio Kase

Takafumi Kawanaka

Hiroaki Matsuda

Haruki Kawada

Shizuo Kitahara

Mitsuyoshi Aonuma

Akio Ueda

Takuji Kishimoto

Tetsuo Ohyama

Tetuya Toyoshima

Kumiko Kohtaki

The invention relates to polybutadiene rubber wherein a molecular weight distribution curve of the rubber as determined by gel permeation chromatography (GPC) has 2 peaks attributable to a high molecular weight component and a low molecular weight component, a peak top molecular weight of the high molecular weight component and a peak top molecular weight of the low molecular weight component fall within ranges of from 100,000 to 1,500,000 and from 10,000 to 50,000, respectively, a ratio of the weight average molecular weight (Mw) to the number average molecular weight (Mn), Mw/Mn, falls within a range of from 4.5 to 14.5, and the content of a cis-1,4 structure is at least 80 wt. %, a high-impact aromatic vinyl resin composition comprising the polybutadiene rubber, and a preparation process of the resin composition.

Polybutadiene rubber and impact-resistant aromatic vinyl resin compositions

An additive for improving the dispersibility of a particulate substance in an organic medium, a thermoplastic polymer, or a thermosetting resin, is at least one compound having a ##STR1## bond in the molecule, including, for example, compounds having an oxazolinium ion in the molecule. The preferred additive compounds are oligomeric or polymeric.

Additive for organic medium or thermoplastic polymer

A rubber composition capable of giving a vulcanized rubber having improved rebound and elongation at break. The composition consists essentially of

Rubber composition

An improved diene type polymer rubber is prepared by reacting a diene type polymer rubber, to which an alkali metal and/or an alkaline earth metal has been added, with a compound represented by the formula: ##STR1## wherein M is oxygen or sulfur, R.sub.1 and R.sub.4 are a substituent having no hydrogen on the .alpha.-carbon atom, R.sub.2 and R.sub.3 are hydrogen or a hydrocarbon group, m is an integer of at least 2, and n is an integer of 2 to 4. The diene type polymer rubber is characterized in that, even after storage for a long time, the Mooney viscosity rises only to a very slight extent, and the rebound, wet skid resistance and other physical properties of the cured product thereof are not substantially changed.

Process for preparation of diene type polymer rubber

A process for modifying a polymer of a conjugated diene, which comprises reacting a polymer of a conjugated diene containing at least one metal selected from alkali metals and alkaline earth metals with a compound having a linkage of the following formula ##STR1## wherein X represents an oxygen or sulfur atom, in the molecule.

Process for modifying conjugated diene polymers

A process for making a diene polymer rubber which comprises reacting an active diene polymer rubber having alkali metal and/or alkaline earth metal terminals, which is obtained by polymerizing a conjugated diene monomer alone or together with an aromatic vinyl monomer in a hydrocarbon solvent, using an alkali metal and/or alkaline earth metal initiator, with

Process for making diene polymer rubbers

A process for making a diene copolymer rubber having improved rebound, which comprises polymerizing a conjugated diene monomer with an aromatic vinyl monomer in a hydrocarbon solvent in the presence of an alkali metal and/or alkaline earth metal initiator, to form a dienyl-metal terminated, conjugated diene-aromatic vinyl copolymer rubber, and thereafter reacting the copolymer rubber with at least one reactant selected from the group consisting of aminoaldehydes, aminoketones, aminothioaldehydes and aminothioketones.

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Kamakura, Japan

Kohkichi Noguchi