Abstract: An ink composition includes (A) at least one polymerizable compound selected from the group consisting of a monofunctional radically polymerizable monomer having an aliphatic cyclic structure, an N-vinyllactam, and an aromatic monofunctional radically polymerizable monomer, (B) a radical polymerization initiator, (C) a pigment, and (D) a graft copolymer having a repeating unit represented by the formula below in a graft chain: wherein R denotes a hydrogen atom or a methyl group, X denotes a single bond, —O—, —CO—, —COO—, —CONR1—, —OCO—, or a phenylene group, R1 denotes a hydrogen atom, an alkyl group, an aryl group, or an aralkyl group, L denotes a single bond or a divalent linking group, Z denotes —NR2R3, R2 and R3 independently denote a hydrogen atom, an alkyl group, an aryl group, or an aralkyl group, and R2 and R3 may be bonded to each other to form a ring.

Abstract: An ink composition containing at least a polymerizable composition, a pigment, and a polymer represented by General Formula (1): where R1 represents an (m+n)-valent organic linking group, R2 represents a single bond or divalent organic linking group; A1 represents a monovalent organic group having a pigment adsorption structure that contains at least one selected from organic pigment structure, heterocyclic structure, acidic group, group having a basic nitrogen atom, urea group, urethane group, group having a coordinating oxygen atom, hydrocarbon group having 4 or more carbon atoms, alkoxysilyl group, epoxy group, isocyanate group, and hydroxyl group; the n groups A1 and bonds or groups R2 may independently be the same or different; “m” is 1 to 8, “n” is 2 to 9, and m+n is 3 to 10; P1 represents a polymer skeleton; and the m skeletons P1 may be the same or different.

Abstract: A pigment dispersion including: 2 to 35% by mass of a pigment (a); 10 to 30 parts by mass of a polymer (b) with respect to 100 parts by mass of the pigment (a), the polymer (b) containing 5 to 30% by mass of a repeating unit represented by the following Formula (1) and having a weight average molecular weight of 10000 to 200000; and 15 to 50 parts by mass of a graft copolymer (c) having a polyalkylene imine chain or a polyallylamine chain in a main chain thereof and a polyester chain in a side chain thereof with respect to 100 parts by mass of the pigment (a), in which a total of the contents of the polymer (b) and the graft copolymer (c) is in the range of 25 to 70 parts by mass with respect to 100 parts by mass of the pigment (a).

Abstract: The present invention provides a pigment dispersion containing at least a pigment at a concentration of from 2 to 50 mass % in the pigment dispersion, and a polymer having from 2 to 50 mass % of repeating units represented by the following formula (1) and from 2 to 40 mass % of repeating units represented by the following formula (2), and having a weight average molecular weight of 10,000 to 500,000. In formula (1), R1 represents a hydrogen atom or a methyl group, I represents —CO—, —COO—, etc., R2 represents an alkyl group having 1 to 4 carbon atoms. In formula (2), R4 represents a hydrogen atom or a methyl group, J represents —CO—, —COO—, etc., R5 represents a hydrogen atom, an alkyl group, an aryl group, etc., W represents a single bond or a bivalent linking group, and P represents a heterocyclic residue having a hetero ring contained in an organic pigment.

Abstract: An ink composition for inkjet is disclosed. The ink composition for inkjet includes a pigment dispersant including a repeating unit having an ultraviolet absorbing group, in an amount of from 0.5% by mass to 20% by mass with respect to the total mass of the pigment dispersant, and a repeating unit having a pigment adsorbing group, in an amount of from 5% by mass to 30% by mass with respect to the total mass of the pigment dispersant; a pigment; a polymerizable compound; and a photopolymerization initiator.

Abstract: The present invention provides: a pigment composition that includes at least (A) a polyallylamine derivative including at least 1% to 50% by mol of a structural unit represented by Formula (1-a), 49% to 95% by mol of a structural unit represented by Formula (1-b) and 1% to 30% by mol of a structural unit represented by Formula (1-c), and (B) a pigment, and improves pigment dispersibility and dispersion stability; an ink composition, a printed article and an inkjet recording method, which use the pigment composition; and a polyallylamine derivative useful for these. In Formula (1-b), R1 represents —NHCOR3 or —NH3+OCOR3, in which R3 represents a residue obtained by removing a carboxy group from any one of polyester, polyamide or polyesteramide, which each have a free carboxylic acid. In Formula (1-c), R2 represents —NHCOR4 or —NH3+OCOR4, in which R4 represents an organic group having an aromatic ring or a heteroaromatic ring.

Abstract: The present invention provides a pigment dispersion, including: (a) a pigment; and (b) a polymer compound as a dispersant for the pigment (a), wherein the polymer compound includes a urethane bond in a main chain, includes a pendant moiety containing a skeleton which is the same as a partial skeleton of the pigment (a), and further includes, at a side chain, at least one polymer chain selected from the group consisting of a polyester chain, a poly(meth)acrylate chain, and a polyalkylene oxide chain, and wherein the molecular weight of the skeleton which is the same as a partial skeleton of the pigment (a) is from 20 to 70% of the molecular weight of the pigment (a).

Abstract: The present invention provides a pigment dispersion, containing (a) a pigment; and (b) a polymer having a polyurethane bond in a main chain, having at least one polymer chain selected from the group consisting of a polyester, a polyacrylate, a polymethacrylate and a polyalkylene oxide at a side chain of the polymer, and having a partial skeleton that is different from a partial skeleton included in a chemical structure of the pigment, as a pendant of the main chain.

Abstract: The present invention provides a pigment dispersion containing at least a pigment at a concentration of from 2 to 50 mass % in the pigment dispersion, and a polymer having from 2 to 50 mass % of repeating units represented by the following formula (1) and from 2 to 40 mass % of repeating units represented by the following formula (2), and having a weight average molecular weight of 10,000 to 500,000. In formula (1), R1 represents a hydrogen atom or a methyl group, I represents —CO—, —COO—, etc., R2 represents an alkyl group having 1 to 4 carbon atoms. In formula (2), R4 represents a hydrogen atom or a methyl group, J represents —CO—, —COO—, etc., R5 represents a hydrogen atom, an alkyl group, an aryl group, etc., W represents a single bond or a bivalent linking group, and P represents a heterocyclic residue having a hetero ring contained in an organic pigment.

Abstract: An ink composition including a cationically polymerizable compound having a styryl or ?-methylstyryl group such as 4-methylstyrene and a photocationic polymerization initiator. The ink composition preferably further includes another cationically polymerizable compound having at least one group selected from oxirane and oxetane groups.

Abstract: The present invention provides: a pigment composition that includes at least (A) a polyallylamine derivative including at least 1% to 50% by mol of a structural unit represented by Formula (1-a), 49% to 95% by mol of a structural unit represented by Formula (1-b) and 1% to 30% by mol of a structural unit represented by Formula (1-c), and (B) a pigment, and improves pigment dispersibility and dispersion stability; an ink composition, a printed article and an inkjet recording method, which use the pigment composition; and a polyallylamine derivative useful for these. In Formula (1-b), R1 represents —NHCOR3 or —NH3+OCOR3, in which R3 represents a residue obtained by removing a carboxy group from any one of polyester, polyamide or polyesteramide, which each have a free carboxylic acid. In Formula (1-c), R2 represents —NHCOR4 or —NH3+OCOR4, in which R4 represents an organic group having an aromatic ring or a heteroaromatic ring.

Abstract: In a fine particle dispersion, fine particles including an oil-soluble dye having an oxidation potential higher than 1.0 V vs SCE and a polymer having at least one of an amide group, a glycidyl group and a hydroxyl group are dispersed in an aqueous medium. Further, an ink composition includes the fine particle dispersion.

Abstract: An ink composition is provided that includes (A) at least one polymerizable compound selected from the group consisting of a monofunctional radically polymerizable monomer having an aliphatic cyclic structure, an N-vinyllactam, and an aromatic monofunctional radically polymerizable monomer, (B) a radical polymerization initiator, (C) a pigment, and (D) a graft copolymer having a repeating unit represented by the Formula below in a graft chain. (In the Formula, R denotes a hydrogen atom or a methyl group, X denotes a single bond, —O—, —CO—, —COO—, —CONR1—, —OCO—, or a phenylene group, R1 denotes a hydrogen atom, an alkyl group, an aryl group, or an aralkyl group, L denotes a single bond or a divalent linking group, Z denotes —NR2R3, R2 and R3 independently denote a hydrogen atom, an alkyl group, an aryl group, or an aralkyl group, and R2 and R3 may be bonded to each other to form a ring.

Abstract: An ink composition containing at least a polymerizable composition, a pigment, and a polymer represented by General Formula (1): where R1 represents an (m+n)-valent organic linking group, R2 represents a single bond or divalent organic linking group; A1 represents a monovalent organic group having a pigment adsorption structure that contains at least one selected from organic pigment structure, heterocyclic structure, acidic group, group having a basic nitrogen atom, urea group, urethane group, group having a coordinating oxygen atom, hydrocarbon group having 4 or more carbon atoms, alkoxysilyl group, epoxy group, isocyanate group, and hydroxyl group; the n groups A1 and bonds or groups R2 may independently be the same or different; “m” is 1 to 8, “n” is 2 to 9, and m+n is 3 to 10; P1 represents a polymer skeleton; and the m skeletons P1 may be the same or different.

Abstract: A polymerizable compound represented by the following formula (1): wherein, in the formula (1), R1 represents any one of a hydrogen atom, a substituted alkyl group, and an unsubstituted alkyl group; R2 represents an alkylene group; W represents any one of —CO—, —C(?O)O—, —CONH—, —OC(?O)—, and a phenylene group; X represents any one of —CO—, —NHCO—, —OC(?O)—, —CH(OH)CH2—, and —SO2—; R3 and R4 represent a monovalent substituent; R3 and R4 may be bound to each other to form a ring structure; and m and n each independently represent 0 or 1.

Abstract: An ink composition including a cationically polymerizable compound having a styryl or ?-methylstyryl group such as 4-methylstyrene and a photocationic polymerization initiator. the ink composition preferably further includes another cationically polymerizable compound having at least one group selected from oxirane and oxetane groups.

Abstract: In a fine particle dispersion, fine particles including an oil-soluble dye having an oxidation potential higher than 1.0 V vs SCE and a polymer having at least one of an amide group, a glycidyl group and a hydroxyl group are dispersed in an aqueous medium. Further, an ink composition includes the fine particle dispersion.