Tokai Carbon Company, Ltd.

Shigehiro Tanaka

Asami Takenaka

Yukari Ishibashi

Makoto Sekiyama

A polyurethane resin-bonded pigment may exhibit excellent image density, dispersibility, storage stability, and resolubility, and may form an ink film that exhibits marker resistance and rubfastness. The polyurethane resin-bonded pigment is produced by bringing (I) a pigment having a surface acidic group into contact with (II) a basic compound having two or more amino groups selected from a primary amino group and a secondary amino group in its molecule in an aqueous medium to obtain a pigment having an unreacted surface amino group, and bringing the pigment having an unreacted surface amino group into contact with (III) a water-dispersible polyurethane resin having an isocyanate end group and (IV) a polyisocyanate compound to bond the pigment having an unreacted surface amino group and the water-dispersible polyurethane resin (III) having an isocyanate end group via a urea bond.

Polyurethane resin addition pigment, process for producing polyurethane resin addition pigment, pigment dispersion composition, and jet printing ink composition

A pigment that exhibits excellent image density, dispersibility, storage stability, and resolubility, and forms an ink film that exhibits marker resistance and rubfastness is provided. A polyurethane resin-bonded pigment is produced by bringing (I) a pigment having a surface acidic group into contact with (II) a water-dispersible polyurethane resin having a tertiary amino group and an anionic polar group or a nonionic polar chain in an aqueous medium. The pigment (I) is preferably self-dispersible carbon black having a surface acidic group.

Polyurethane resin adhesion pigment, pigment dispersion composition and inkjet ink composition

A method for producing a pigment dispersion composition having excellent image density, dispersibility, and storage stability, has high resolubility, and forms an ink film having excellent marker resistance and scratch resistance. The method includes bringing a pigment (I) having a surface acidic group and a basic compound (II) having two or more ammo groups selected from a primary amino group and a secondary amino group in its molecule, into contact with each other in an aqueous medium to prepare a pigment having an unreacted surface amino group, bringing the pigment into contact with a polyisocyanate polyurethane resin (III) having two or more isocyanate end groups so that the pigment and the polyisocyanate polyurethane resin are bonded via a urea bond to prepare a dispersion of a polyurethane resin-bonded pigment (A), and heating the dispersion of the polyurethane resin-bonded pigment (A) at 40 to 100&#xb0; C. for 1 to 30 days.

Process for producing pigment dispersion composition

A method of producing a polyurethane resin-bonded pigment aqueous dispersion includes causing (I) a pigment having a surface acidic group to come in contact with (II) a basic compound having two or more amino groups selected from a primary amino group and a secondary amino group in its molecule in an aqueous medium so that the pigment has an unreacted surface amino group, and causing the pigment to come in contact and react with (III) a polyurethane resin having an isocyanate end group. A polyurethane resin-bonded pigment aqueous dispersion produced by the method exhibits excellent image density, dispersibility, and storage stability.

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Tokyo, Japan

Shigehiro Tanaka