Method for dispersing pigment and water-based pigment dispersion
AssigneeToyo Ink Manufacturing Co., Ltd.
InventorsAtsushi Endo, Akimitsu Mochizuki, Tadashi Itabashi, Masami Kuwabara
Life of this patent
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Abstract
A method is disclosed for dispersing a pigment to obtain a pigment dispersion. The method involves dispersing 100 parts by weight of a pigment, 0.1 to 30 parts by weight of a specific pigment dispersing agent and 5 to 300 parts by weight of a water-based resin in 100 to 2,000 parts by weight of an aqueous medium having a water-soluble organic solvent concentration of 4 to 15% by weight. Pigments are obtained which are suitable for the production of water-based coating compositions or water-based inks excellent in fluidity, storage stability, gloss of a coating, sharpness and tinting strength.
Claims6
A pigment dispersion containing
- (a) 100 parts by weight of a pigment,
- (b) 0.1 to 30 parts by weight of a pigment dispersing agent of the formula ##STR3## wherein P is an organic dyestuff residue or a heterocyclic ring residue, X is a direct bond, --N-- or --X.sup.1 --X.sup.2 --R.sup.5 --X.sup.3 -- in which X.sup.1 is a direct bond, --SO.sub.2 --, --CO--, --CH.sub.2 -- or --CH.sub.2 NHCOCH.sub.2 --, each of X.sup.2 and X.sup.3 is independently --O-- or --NH-- and R.sup.5 is an alkylene group having 1 to 10 carbon atoms, a phenylene group, a methyl-substituted phenylene group, a dimethyl-substituted phenylene group or an ethyl-substituted phenylene group, Y is a direct bond, --N(R.sub.4)--R.sup.3 or --O--R.sup.3 -- in which R.sup.3 is an alkylene group having 1 to 10 carbon atoms or a phenylene group, R.sup.4 is H, an alkyl group having 1 to 18 carbon atoms or --R.sup.3 --N(R.sup.1)R.sup.2, Z is a hydroxyl group, an alkoxy group having 1 to 4 carbon atoms or
- --Y--N(R.sup.1)R.sup.2, each of R.sup.1 and R.sup.2 is independently an alkyl group having 1 to 18 carbon atoms, or R.sup.1 and R.sup.2 together with the nitrogen to which they are attached form a heterocyclic ring which may additionally contain N, O or S, and n is an integer of 1 to 3, and
- (c) 5 to 300 parts by weight of a water-based resin, dispersed in 100 to 2,000 parts by weight of an aqueous medium the dispersion having a water-soluble organic solvent concentration of 4 to 15% by weight based on the total amount of aqueous media.
A method for dispersing a pigment which comprises
- mixing 100 parts by weight of a pigment and 0.1 to 30 parts by weight of a pigment dispersing agent of the formula ##STR4## wherein P is an organic dyestuff residue or a heterocyclic ring residue, X is a direct bond, --N-- or --X.sup.1 --X.sup.2 --R.sup.5 --X.sup.3 -- in which X.sup.1 is a direct bond, --SO.sub.2 --, --CO--, --CH.sub.2 -- or --CH.sub.2 NHCOCH.sub.2 --, each of X.sup.2 and X.sup.3 is independently --O-- or --NH-- and R.sup.5 is an alkylene group having 1 to 10 carbon atoms, a phenylene group, a methyl-substituted phenylene group, a dimethyl-substituted phenylene group or an ethyl-substituted phenylene group, Y is a direct bond, --N(R.sup.4)--R.sup.3 or --O--R.sup.3 -- in which R.sup.3 is an alkylene group having 1 to 10 carbon atoms or a phenylene group, R.sup.4 is H, an alkyl group having 1 to 18 carbon atoms or --R.sup.3 --N(R.sup.1)R.sup.2, Z is a hydroxyl group, an alkoxy group having 1 to 4 carbon atoms or
- --Y--N(R.sup.1)R.sup.2, each of R.sup.1 and R.sup.2 is independently an alkyl group having 1 to 18 carbon atoms, or R.sup.1 and R.sup.2 together with the nitrogen to which they are attached form a heterocyclic ring which may additionally contain N, O or S, and n is an integer of 1 to 3, in 100 to 2,000 parts by weight of an aqueous medium having a water-soluble organic solvent concentration of 10 to 25% by weight, and
- adding to the resultant mixture 5 to 300 parts by weight of a water-based resin and water or a water-soluble organic solvent to form a dispersion having a water-soluble organic solvent concentration of 4 to 15% by weight based on the total amount of aqueous media.
Dependencies are inferred from the claim text.