Nanosized particles of benzimidazolone pigments
View Patent ↗A nanoscale pigment particle composition includes an organic benzimidazolone pigment, and a sterically bulky stabilizer compound, wherein the benzimidazolone pigment associates non-covalently with the sterically bulky stabilizer compound; and the presence of the associated stabilizer limits the extent of particle growth and aggregation, to afford nanoscale-sized pigment particles.
1. A nanoscale pigment particle composition, comprising:
a benzimidazolone pigment, and
a sterically bulky stabilizer compound associated non-covalently with the benzimidazolone pigment;
wherein presence of the stabilizer limits an extent of particle growth and aggregation, to afford nanoscale-sized pigment particles.
2. The composition of claim 1 , wherein the nanoscale-sized pigment particles have an average particle diameter as derived from transmission electron microscopy imaging, of less than about 150 nm.
3. The composition of claim 1 , wherein the benzimidazolone pigment comprises a diazo component group and a nucleophilic coupling component group that are linked together with one azo group, wherein at least one of the diazo component group and the nucleophilic coupling component group comprises a benzimidazolone functional moiety.
4. The composition of claim 3 , wherein the diazo component group is selected from the group consisting of DC 1 to DC 5 :
wherein:
* indicates the point of attachment to the azo group in the benzimidazolone pigment,
R 1 to R 7 independently represent H; CH 3 ; CO 2 H; CO 2 CH 3 ; CO 2 (CH 2 ) n CH 3 wherein n=0-5; CONH 2 ; (CO)R a R b wherein R a and R b can independently represent H, C 6 H 5 , (CH 2 ) n CH 3 wherein n=0-12, or (CH 2 ) n N(CH 3 ) 2 wherein n=1-5; OCH 3 ; OCH 2 CH 2 OH; NO 2 ; SO 3 H; Cl; Br; I; F; or any of the following structural groups:
in DC 2 and DC 3 R′ represents H, (CH 2 ) n CH 3 , or C 6 H 5 , and n represents a number of from 1 to about 6.
5. The composition of claim 3 , wherein the nucleophilic coupling component group is selected from the group consisting of:
wherein R 6 , R 7 , R 8 , R 9 , and R 10 independently represent H, Br, Cl, I, F, or CH 3 , and * denotes the point of attachment to the azo group.
6. The composition of claim 1 , wherein the sterically bulky stabilizer is associated with the benzimidazolone pigment predominantly by hydrogen bonding.
7. The composition of claim 1 , wherein the sterically bulky stabilizer comprises at least one aliphatic hydrocarbon moiety.
8. The composition of claim 1 , wherein the sterically bulky stabilizer is selected from the group consisting of mono- and di-carboxylic acids; mono- and di-esters; mono- and di-primary amide derivatives of pyridine, piperidine, piperazine, morpholine and pyrroles; monosubstituted pyridine, piperazine, piperidine, morpholine, pyrrole, imidazole, and thiazole, and cationic salts thereof, substituted by a long-chain or branched aliphatic hydrocarbon; poly(vinyl pyrrolidone) and copolymers of poly(vinyl pyrrolidone) with α-olefins; poly(vinyl imidazole) and copolymers of poly(vinyl imidazole) with α-olefins; poly(vinyl pyridine) and copolymers of poly(vinyl pyridine) with α-olefins or styrene; long-chain or branched aliphatic primary amides and amidines; semicarbazides and hydrazones of long-chain aliphatic and/or branched aldehydes and ketones; mono-substituted ureas and N-alkyl-N-methyl ureas, substituted by a long-chain or branched aliphatic hydrocarbon; mono-substituted monosubstituted guanidines and guanidinium salts, substituted by a long-chain or branched aliphatic hydrocarbon; mono- and di-substituted succinimides; mono- and di-substituted succinic acids or their esters, comprising one or more alkyl substituent comprised of a long-chain or branched aliphatic hydrocarbon having between 6 and 50 carbon atoms; and mixtures thereof.
9. The composition of claim 1 , wherein the sterically bulky stabilizer is selected from the group consisting of the following compounds:
wherein m is an integer of 0 to 12, and R is H, CH 3 , or (CH 2 ) n CH 3 where n is an integer of 0 to 6,
where m is an integer of 0 to 12, R is H or CH 3 , and Z is Cl, Br, I, SO 4 2− , MeSO 4 − , or O 3 S-p-(C 6 H 4 )CH 3 ,
where m is an integer of 0 to 12, and X is O, NH, or S,
where m is an integer of 0 to 12, X is O, NH, or S, and Z is OH, NH 2 , H, or CH 3 ,
where each m is an integer of 0 to 12, and each X is O, NH, or S,
where n is an integer of 0 to 10,
where n is an integer of 0 to 25,
where each Z is H, OH, NH 2 , NHR′, or OR′, where R′ is C 1 -C 6 alkyl or C 6 -C 14 aryl group,
where n is an integer of 1 to 30,
where m is an integer of 1 to 30, and n is an integer of 1 to 11,
where n is an integer of 1 to 30,
where n is an integer of 1 to 14, and
where n is an integer of 1 to 30.
10. The composition of claim 1 , further comprising a surfactant selected from the group consisting of derivatives of rosin natural products; long-chain or branched hydrocarbon alcohols; alcohol ethoxylates; acrylic-based polymers; styrene-based copolymers; copolymers of α-olefins; copolymers of vinyl pyridine, vinyl imidazole, and vinyl pyrrolidinone; polyester copolymers; polyamide copolymers; and copolymers of acetals and acetates.
11. A process for preparing nanoscale particles of benzimidazolone pigments, comprising:
providing one or more organic pigment precursors to a benzimidazolone pigment comprising a benzimidazolone moiety,
providing a solution or suspension of a sterically bulky stabilizer compound that associates non-covalently with the benzimidazolone moiety on one of the pigment precursors, and
carrying out a chemical coupling reaction to form a benzimidazolone pigment composition comprising nanoscale-sized pigment particles, whereby the pigment precursors are incorporated with the benzimidazolone pigment and one or more functional moieties on the benzimidazolone pigment is non-covalently associated with the steric stabilizer, so as to limit an extent of particle growth and aggregation.
12. The process of claim 11 , wherein the nanoscale-sized pigment particles have an average particle diameter as derived from transmission electron microscopy imaging, of less than about 150 nm.
13. The process of claim 11 , further comprising adding a surfactant selected from the group consisting of rosin compounds; long-chain or branched hydrocarbon alcohols; alcohol ethoxylates; acrylic-based polymers; styrene-based copolymers; copolymers of α-olefins; copolymers of vinyl pyridine, vinyl imidazole, and vinyl pyrrolidinone; polyester copolymers; polyamide copolymers; and copolymers of acetals and acetates.
14. The process of claim 11 , wherein the non-covalent association between the benzimidazolone pigment and the sterically bulky stabilizer compound is predominantly hydrogen bonding.
15. The process of claim 11 , comprising:
preparing a first reaction mixture comprising: (a) a diazonium salt as a first precursor to the benzimidazolone pigment and (b) a liquid medium containing diazotizing agents in acid solution or suspension; and
preparing a second reaction mixture comprising: (a) a benzimidazolone coupling agent as a second precursor to the benzimidazolone pigment and (b) a sterically bulky stabilizer compound that can associate non-covalently with the coupling agent; and (c) a liquid medium
combining the first reaction mixture into the second reaction mixture to form a third mixture and
effecting a direct coupling reaction which forms a benzimidazolone pigment composition having nanoscale-sized particles and wherein the benzimidazolone pigment associates non-covalently with the sterically bulky stabilizer.
16. The process of claim 15 , wherein the second reaction mixture further comprises one or more additives selected from the group consisting of inorganic and organic buffers, alkaline bases, and acids.
17. The process of claim 15 , wherein the combining is conducted at ambient temperature with stirring.
18. The process of claim 15 , wherein the benzimidazolone pigment comprises a diazo component group and a nucleophilic coupling component group that are linked together with one azo group, wherein at least one of the diazo component group and the nucleophilic coupling component group comprises a benzimidazolone functional moiety.
19. The process of claim 18 , wherein the diazo component group is selected from the group consisting of DC 1 to DC 5 :
wherein:
* indicates the point of attachment to the azo group in the benzimidazolone pigment,
R 1 to R 7 independently represent H; CH 3 ; CO 2 H; CO 2 CH 3 ; CO 2 (CH 2 ) n CH 3 wherein n=0-5; CONH 2 ; (CO)R a R b wherein R a and R b can independently represent H, C 6 H 5 , (CH 2 ) n CH 3 wherein n=0-12, or (CH 2 ) n N(CH 3 ) 2 wherein n=1-5; OCH 3 ; OCH 2 CH 2 OH; NO 2 ; SO 3 H; Cl; Br; I; F; or any of the following structural groups:
in DC 2 and DC 3 R′ represents H, (CH 2 ) n CH 3 , or C 6 H 5 , and n represents a number of from 1 to about 6.
20. The process of claim 18 , wherein the nucleophilic coupling component group is selected from the group consisting of:
wherein R 6 , R 7 , R 8 , R 9 , and R 10 independently represent H, Br, Cl, I, F, or CH 3 , and * denotes the point of attachment to the azo group.
21. The process of claim 15 , wherein the sterically bulky stabilizer is selected from the group consisting of mono- and di-carboxylic acids; mono- and di-esters; mono- and di-primary amide derivatives of pyridine, piperidine, piperazine, morpholine and pyrroles; monosubstituted pyridine, piperazine, piperidine, morpholine, pyrrole, imidazole, and thiazole, and cationic salts thereof, substituted by a long-chain or branched aliphatic hydrocarbon; poly(vinyl pyrrolidone) and copolymers of poly(vinyl pyrrolidone) with α-olefins; poly(vinyl imidazole) and copolymers of poly(vinyl imidazole) with α-olefins; poly(vinyl pyridine) and copolymers of poly(vinyl pyridine) with α-olefins or styrene; long-chain or branched aliphatic primary amides and amidines; semicarbazides and hydrazones of long-chain aliphatic and/or branched aldehydes and ketones; mono-substituted ureas and N-alkyl-N-methyl ureas, substituted by a long-chain or branched aliphatic hydrocarbon; mono-substituted monosubstituted guanidines and guanidinium salts, substituted by a long-chain or branched aliphatic hydrocarbon; mono- and di-substituted succinimides; mono- and di-substituted succinic acids or their esters, comprising one or more alkyl substituent comprised of a long-chain or branched aliphatic hydrocarbon having between 6 and 50 carbon atoms; and mixtures thereof.
22. The process of claim 15 , wherein the sterically bulky stabilizer is selected from the group consisting of the following compounds:
wherein m is an integer of 0 to 12, and R is H, CH 3 , or (CH 2 ) n CH 3 where n is an integer of 0 to 6,
where m is an integer of 0 to 12, R is H or CH 3 , and Z is Cl, Br, I, SO 4 2− , MeSO 4 − , or O 3 S-p-(C 6 H 4 )CH 3 ,
where m is an integer of 0 to 12, and X is O, NH, or S,
where m is an integer of 0 to 12, X is O, NH, or S, and Z is OH, NH 2 , H, or CH 3 ,
where each m is an integer of 0 to 12, and each X is O, NH, or S,
where n is an integer of 0 to 10,
where n is an integer of 0 to 25,
where each Z is H, OH, NH 2 , NHR′, or OR′, where R′ is C 1 -C 6 alkyl or C 6 -C 14 aryl group,
where n is an integer of 1 to 30,
where m is an integer of 1 to 30, and n is an integer of 1 to 11,
where n is an integer of 1 to 30,
where n is an integer of 1 to 14, and
where n is an integer of 1 to 30.
23. An ink composition comprising:
a carrier, and
a colorant comprising a nanoscale pigment particle composition according to claim 1 .
24. The ink composition of claim 23 , wherein the ink composition is selected from the group consisting of solid ink compositions, phase change ink compositions, curable ink compositions, aqueous ink compositions, and non-aqueous ink compositions.
25. A toner composition comprising:
a binder resin, and
a colorant comprising a nanoscale pigment particle composition according to claim 1 .