Kureha Kagaku Kogyo Kabushiki Kaisha

Toyo Boseki Kabushiki Kaisha

Kureha Kagaku Kogyo K.k.

Haruhiko Yusa

Masanori Oota

Mitsuru Hoshino

Kazuo Takahashi

Yo Iizuka

Katsumi Suzuki

Haruki Isaka

Humio Akutsu

Chikara Sugitawa

Hironobu Furusawa

Hideyuki Hashizume

Susumu Midorikawa, Deceased

Katumi Suzuki

By Taeko Midorikawa, Heir

Susumu Chubachi

Akira Kurosaki

In a process for producing a rubber-containing graft copolymer, which comprises bringing a latex of a graft copolymer comprising 60% to 90% by weight of a rubbery polymer and 40% to 10% by weight of a hard polymer, said graft copolymer latex being obtained by emulsion polymerizing a hard polymer-forming monomer in a latex of said rubbery polymer and having a minimum film-forming temperature of 75.degree. C. or less, into contact with an aqueous electrolyte solution under stirring, thereby to coagulate the latex, and recovering the precipitated graft copolymer, the improvement is disclosed such that the graft copolymer latex is subjected to slow coagulation so as to allow the graft copolymer to precipitate as substantially spherical particles, wherein the term 'slow coagulation' refers to coagulation which proceeds at a milder rate than that of coagulation in which the aqueous electrolyte solution is hydrochloric acid and the pH of the latex during coagulation is 1.8 or less.

Process for producing rubber-based graft copolymers

A polyvinyl chloride resin composition comprises 3-30 wt. % of a graft copolymer and 97-70 wt. % of a polyvinyl chloride resin and has highly-balanced properties between impact resistance, transparency and stress-whitening resistance and excellent processing characteristics. The graft copolymer is obtained by graft-polymerizing, in the presence of a latex containing greater than 75 but not exceeding 85 parts by weight of a rubbery butadiene-styrene copolymer formed of 65-85 wt. % of butadiene, 15-35 wt. % of styrene and 0-3 wt. % of crosslinkable monomer, (i) 5-24 parts by weight of a first monomer mixture as a first-stage component, said first monomer mixture being composed of 70-97 wt. % of methyl methacrylate and 30-3 wt. % of an alkyl acrylate whose alkyl group has 1-8 carbon atoms; and then (ii) 3-21 parts by weight of a second monomer mixture as a second-stage component, said second monomer mixture being composed of 97-100 wt % of styrene and 0-3 wt. % of crosslinkable monomer. The sum of the first and second monomer mixtures and the rubbery butadiene-styrene copolymer is 100 parts by weight. The monomers grafted in the first stage amount to 30-80 wt. % of the sum of the grafted monomers.

Polyvinyl chloride resin composition

An impact-resistant thermoplastic resin composition having excellent transparency and appearance properties which comprises (A) a butadiene-styrenemethyl methacrylate-alkyl acrylate graft copolymer obtained by postpolymerization of styrene, methyl methacrylate and an alkyl acrylate to a latex comprising a butadiene homopolymer rubber or a butadiene-styrene copolymer rubber comprising mainly butadiene and having an average particle diameter of 0.1 to 0.5 .mu., and (B) a methyl methacrylate-styrene copolymer. This composition has quantitative limitation.

Thermoplastic resin composition

Disclosed herein is a composition of a polyester-block copolymer, comprising 5 to 80% by weight of at least one kind of graft-copolymer obtained by graft-copolymerizing 50 to 25 parts by weight of a monomeric mixture predominantly consisting essentially of styrene and methyl methacrylate and containing 0.01 to 3.0% by weight of a cross-linking agent with 50 to 75 parts by weight of a cross-linked elastomeric trunk polymer containing not less than 50% by weight of rubber like segment selected from the group consisting of butadiene unit and C.sub.4 to C.sub.10 -alkyl acrylate units, and 0.01 to 3.0% by weight of a cross-linking agent, and 95 to 20% by weight of a polyester-block copolymer, the composition giving shaped articles of favorable superficial appearance even when processed by shape-forming under conditions of mixing and kneading of a relatively low degree.

Composition of polyester-block copolymer

Modified titanium oxide is prepared by polymerizing a mixture of vinyl chloride and a carboxylic monomer such as 10-undecenoic acid in the presence of titanium oxide. The thus obtained, modified titanium oxide is mixed with a vinyl chloride resin, typically, polyvinyl chloride to give a vinyl chloride resin composition having an improved weatherability and being substantially free of serious drawbacks accompanying the addition of conventional titanium oxide such as plating out during extrusion and decrease in extrusion throughput.

Vinyl chloride resin composition

A monomer mixture comprising .alpha.-methylstyrene or 2-isopropenylnaphthalene, methyl methacrylate, and acrylonitrile is polymerized in the presence of a crosslinked polymer obtained by copolymerizing a monofunctional monomer such as .alpha.-methylstyrene with a small quantity of a polyfunctional monomer such as divinylbenzene to obtain a copolymer (C). A vinyl chloride resin composition formulated by blending the copolymer (C) thus obtained with a vinyl chloride resin and an impact strength modifier resin in a specific proportion possesses improved thermal deformation resistance and impact strength while retaining processability comparable to that of the vinyl chloride resin mixed with the impact strength modifier resin.

A process for producing a graft-polymer comprises adding an aqueous solution of a salt of a strong acid and a monovalent strong base, which solution has been adjusted to a pH value of 8 to 13, to a rubber latex containing diene rubber particles and a fatty acid soap as an emulsifying agent to coagulate the above mentioned rubber particles, and thereafter adding a vinyl monomer to the latex containing the coagulated rubber particles to graft-polymerize the vinyl monomer. According to this process, the formation of rubber masses and macroparticles during the coagulation is reduced and a rubber latex containing rubber particles having a narrow range of particle size distribution is obtained. When a graft-copolymer obtained by using the latex is blended with thermoplastic resins such as vinyl chloride resins, the impact resistance of the thermoplastic resins can be remarkably improved without impairing their transparency and gloss.

Process for producing a graft-copolymer and blends therewith

Graft-copolymers for improving impact strength comprising a relatively large quantity of an elastomeric trunk polymer, such as acrylonitrile/styrene/butadiene resins and methyl methacrylate/styrene/butadiene resins, have some undesirable powder characteristics, for example, poor fluidity and an easily blocking property. However, by blending a graft-copolymer of this type with a graft-copolymer comprising a relatively small quantity of an elastomeric trunk polymer in slurry form or dry state, it is possible to obtain a graft-copolymer blend with improved powder characteristics without significantly lowering the effect of improving the impact strength of the former graft-copolymer. The graft-copolymer blend thus obtained, when blended with a hard resin such as polyvinyl chloride, provides a resin composition with high impact strength.

Powdery graft-copolymer composition

A composition comprising polyvinyl chloride and a novel polymer processing aid is provided. The polymer processing aid can be obtained either by blending in latex form an alkyl methacrylate copolymer (A) and a copolymer (B) comprising as its essential constituents an alkyl methacrylate, a dialkyl itaconate or an alkyl acrylate, and a diolefin, or by copolymerizing one of the copolymers in the presence of the other copolymer. The polymer processing aid thus obtained improves the processability of the vinyl chloride resin composition with less reduction in impact strength.

Vinyl chloride resin composition with processing aid

A resinous composition having fire retardance, impact resistance and easy workability is obtained by blending (1) about 80 to 30 parts by weight of an ABS resin with (2) about 20 to 70 parts by weight of (i) a vinyl chloride resin compound comprising 100 to 5 parts by weight of a copolymer resin consisting essentially of 0.5 to 40% by weight of a higher alkyl vinyl ether and 99.5 to 60% by weight of vinyl chloride and (ii) 0 to 95 parts by weight of a polyvinyl chloride resin.

Fire retardant resinous compositions

Vinyl chloride resin composition having excellent impact resistance, weather resistance and processability which comprises a vinyl chloride resin and a multicomponent resin blended therewith, said multicomponent resin being prepared by (1) graft polymerizing acrylonitrile, and a vinyl monomer which is methyl methacrylate and/or styrene, and a cross-linking agent onto cross-linked copolymer rubber obtained by emulsion-polymerizing an alkyl acrylate, butadiene and a cross-linking agent or onto a cross-linked terpolymer rubber obtained by emulsion-polymerizing an alkyl acrylate, butadiene, methyl methacrylate and a cross-linking agent and (2) further graft polymerizing thereonto an alkyl methacrylate and a cross-linking agent. Quantitative limitations are included.

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Iwaki, Japan

Haruhiko Yusa