Sekisui Chemical Co., Ltd.

Hiroaki Takehara

Takashi Ueyama

Masazumi Okudo

Yuki Hirose

Takayuki Maeda

Takashi Shinjo

Motokuni Ichitani

Toshiharu Furukawa

An object of the present invention is to provide a method for producing a cross-linked polyvinyl acetal resin, which can provide a cross-linked polyvinyl acetal resin having high mechanical strength and excellent solvent resistance by a simple method without a cross-linking agent, and can solve such problems as sheet attack, insufficient strength, and instability of viscosity for a long-time storage, and another object of the present invention is to provide a cross-linked polyvinyl acetal resin produced by the above method for producing a cross-linked polyvinyl acetal resin. The method for producing a cross-linked polyvinyl acetal resin comprises the step of irradiating a polyvinyl acetal resin at least having structural units represented by the following formulas (1) to (4) with ultraviolet light having a wavelength in a range of 200 to 365 nm, wherein Rrepresents a hydrogen atom or a C1-C20 hydrocarbon group; and Rrepresents a group having two or more functional groups, the two or more functional groups each selected from the group consisting of the functional groups represented by the following formulas (5), (6), and (7). 

Method for production of crosslinked polyvinyl acetal resin, and crosslinked polyvinyl acetal resin

A toner resin composition characterized as containing a vinyl copolymer prepared principally from a styrene monomer and a (meth)acrylic ester monomer and showing peaks at least in the molecular weight range of 5,000-20,000 and in the molecular weight range of not below 500,000 when its molecular weight distribution is determined by gel permeation chromatography, 2-10% by weight of Fischer-Tropsch wax, and 0.5-5% by weight of styrenic block copolymer; and a toner incorporating the toner resin composition.

Toner resin composition and toner

A toner resin composition, as well as a toner prepared therefrom, are disclosed which are excellent in fixability, offset resistance and storage stability, and which result in reduced occurrence of DF staining. The toner resin composition includes (a) a vinyl copolymer containing 25 or lower % by weight of molecular species having molecular weights of 200,000 or higher; and (b) 3 to 10% by weight of ethylene-based olefin polymer which has a DSC-determined peak (melting point) within a range of 85-100.degree. C., a weight average molecular weight (Mw) within a range of 500-900, a number average molecular weight (Mn) within a range of 500-900, and a melt viscosity of 10 to 17 cps at 100.degree. C.

Toner resin composition and toner prepared therefrom

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Shiga, Japan

Hiroaki Takehara