Dainichiseika Color & Chemicals Mfg. Co., Ltd.

Toshie Okubo

Hiroyuki Shimanaka

Sachio Yoshikawa

Jun Kamabayashi

Lu Tian

Akifumi Tanaka

Yoshikazu Murakami

The present invention provides an A-B block copolymer that enables preparation of a polymer emulsion useful as a binder component for an aqueous inkjet ink that is excellent in inkjet printability and is capable of forming a printed film excellent in durability, such as adhesiveness and rub resistance, on a substrate to be printed, such as a polyolefin-based plastic film. The block copolymer is an A-B block copolymer satisfying the following requirements (1-1) to (1-3). (1-1) Containing 90% by mass or more of a constituent unit derived from a methacrylate-based monomer or the like. (1-2) The chain A has a constituent unit (A-i) derived from methyl methacrylate or the like and a constituent unit (A-ii) derived from 2-ethylhexyl methacrylate or the like. (1-3) The chain B has a constituent unit (B) derived from methacrylic acid, a constituent unit (B-i) derived from methyl methacrylate or the like, and a constituent unit (B-ii) derived from 2-ethylhexyl methacrylate or the like.

A-B block copolymer, polymer emulsion and water-based inkjet ink

An aqueous pigment dispersion for preparing an environmentally conscious aqueous inkjet ink in which a pigment is finely and stably dispersed and which records images having excellent durability, glossiness, color developability, and adhesiveness to various printing substrates. The aqueous pigment dispersion contains a pigment, water, a water-soluble organic solvent, and a polymeric dispersant that disperses the pigment. The polymeric dispersant is a polymer including a constitutional unit (i) derived from (meth)acrylic acid and/or itaconic acid, and a constituent unit (ii) derived from (meth)acrylate derived from biological material, such as ethyl (meth)acrylate, having an acid value of 30 to 250 mgKOH/g, number average molecular weight of 1,000 to 30,000, and a polydispersity index (weight average molecular weight/number average molecular weight) of 2.5 or less. The content of the constituent unit (ii) is 50% by mass or more, and at least part of carboxy groups is neutralized with an alkali.

Aqueous pigment dispersion liquid, aqueous ink-jet ink, and dry coating

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Tokyo, Japan

Toshie Okubo