Pigment dispersion and offset printing ink composition using the same
AssigneeSakata Inx Corporation
InventorsKoji Iwase, Hideki Kinoshita, Teruhisa Sato, Hiroyuki Ishikawa
Life of this patent
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Abstract
A pigment dispersion is disclosed which comprises a pigment, a pigment dispersant, and optionally a binder resin, wherein the pigment dispersion comprises as the pigment dispersion at least 0.2 parts by weight of a modified novolak resin (A) and/or a graft copolymer (B) relative to 100 parts by weight of the pigment, the modified novolak resin (A) and the graft copolymer (B) each having an aromatic ring and a ring structure given by ring opening of an epoxy group by a carboxyl group of a hydroxycarboxylic acid or a derivative thereof. An ink composition for offset printing containing the pigment dispersion is also disclosed.
Claims7
A pigment dispersion comprising a pigment, a pigment dispersant, a solvent and optionally a binder resin;
- the pigment dispersion comprising as the pigment dispersant at least 0.2 part by weight of a copolymer (B) relative to 100 parts by weight of the pigment,
- the copolymer (B) having a weight average molecular weight of 3,000 to 100,000 and consisting essentially of 10 to 90% by mole of a recurring unit represented by formula (2), 10 to 90% by mole of at least one recurring unit selected from the group consisting of recurring units represented by formulae (3) and (4):
- ##STR33## wherein W.sup.2 and X.sup.2 are independently each a divalent hydrocarbon group having 1 to 19 carbon atoms;
- p and q are an integer of 1 to 30 and an integer of 0 to 30, respectively;
- R.sup.2, R.sup.3 and R.sup.4 are independently each a hydrogen atom or a methyl group;
- R.sup.5 is a hydrogen atom or a halogen atom;
- R.sup.6 and R.sup.7 are independently each a hydrogen atom, a hydrocarbon group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, an aryloxy group having 6 to 10 carbon atoms or a halogen atom;
- R.sup.8 is a hydrogen atom or a methyl group;
- and R.sup.9 is a direct bond or a methylene group, and 0 to 80% by mole of a recurring unit derived from an ethylenic unsaturated monomer having no functional group highly reactive to an epoxy group selected from the group consisting of an alkyl ester of (meth)acrylic acid, a (meth)acrylate having a cyclic ether group, a (meth)acrylate having a hydroxyl group on an aliphatic carbon, a (meth)acrylate having a tertiary amino group, an alkyl vinyl ether, a vinyl ether having a hydroxyl group on an aliphatic carbon and an allyl ester of an acid.
An ink composition for offset printing comprising a pigment dispersion, a binder resin and a solvent;
- the pigment dispersion comprising a pigment, a pigment dispersant, a solvent and optionally a binder resin;
- the pigment dispersion comprising as the pigment dispersant at least 0.2 part by weight of a copolymer (B) relative to 100 parts by weight of the pigment,
- the copolymer (B) having a weight average molecular weight of 3,000 to 100,000 and consisting essentially of 10 to 90% by mole of a recurring unit represented by formula (13), 10 to 90% by mole of at least one recurring unit selected from the group consisting of recurring units represented by formulae (3) and (4):
- ##STR38## wherein W.sup.4 and X.sup.4 are independently each a divalent hydrocarbon group having 11 to 19 carbon atoms;
- p and q are an integer of 1 to 30 and an integer of 0 to 30, respectively;
- R.sup.2, R.sup.3 and R.sup.4 are independently each a hydrogen atom or a methyl group;
- R5 is a hydrogen atom or a halogen atom;
- R.sup.6 and R.sup.7 are independently each a hydrogen atom, a hydrocarbon group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, an aryloxy group having 6 to 10 carbon atoms or a halogen atom;
- R.sup.8 is a hydrogen atom or a methyl group;
- and R.sup.9 is a direct bond or a methylene group, and 0 to 80% by mole of a recurring unit derived from an ethylenic unsaturated monomer having no functional group highly reactive to an epoxy group selected from the group consisting of an alkyl ester of (meth)acrylic acid, a (meth)acrylate having a cyclic ether group, a (meth)acrylate having a hydroxyl group on an aliphatic carbon, a (meth)acrylate having a tertiary amino group, an alkyl vinyl ether, a vinyl ether having a hydroxyl group on an aliphatic carbon and an allyl ester of an acid.
Dependencies are inferred from the claim text.