JP2020070322A - Water dispersion of coloring resin particle, inkjet ink, and method for producing water dispersion of coloring resin particle - Google Patents

Abstract

To provide a water dispersion of coloring resin particles excellent in storage stability and an inkjet ink.SOLUTION: A water dispersion of coloring resin particles contains coloring resin particles, an acidic emulsifier and water, in which the coloring resin particles contain a pigment, a water-insoluble acidic dispersant and a water-soluble vinyl polymer containing a unit represented by formula (1), a hydrophobic unit and a basic unit. In formula (1), Rrepresents a hydrogen atom or a methyl group, Rrepresents a hydrogen atom, an alkyl group having 1 to 10 carbon atoms or a phenyl group that may be substituted with an alkyl group having 1 to 9 carbon atoms, AO each independently represents an ethyleneoxy group or a propyleneoxy group, m is 4-100 that is the total of an average addition mole number p of the ethyleneoxy group and an average addition mole number q of the propyleneoxy group, p is 1 or more, q is 0 or more, and * represents a binding site with other unit.SELECTED DRAWING: None

Description

  The present invention relates to an aqueous dispersion of colored resin particles, an inkjet ink, and a method for producing an aqueous dispersion of colored resin particles.

  The inkjet recording method is a method of ejecting highly fluid inkjet ink as droplets from fine nozzles and recording an image on a recording medium placed facing the nozzles, which enables high-speed printing with low noise. Therefore, it has become popular rapidly in recent years. As the ink used in such an ink jet recording system, a water-based ink containing water as a main solvent, an ultraviolet curable ink (UV ink) containing a polymerizable monomer as a main component in a high content, and a wax as a main component are high. A so-called non-aqueous ink that contains a non-aqueous solvent as a main solvent together with a hot-melt ink (solid ink) that is contained at a content is known.

  Aqueous inkjet inks that use pigments are required to have a small pigment particle size and long-term dispersion stability in order to ensure stable ejection.

  Patent Documents 1 and 2 disclose, as an aqueous ink having excellent dispersion stability, an aqueous ink for inkjet recording containing an aqueous dispersion of water-insoluble vinyl polymer particles containing a colorant.

  Patent Documents 3 to 5 use a water-soluble polymer having an anionic group and a water-insoluble polymer having an anionic group as a pigment aqueous dispersion for inkjet recording or an aqueous ink for inkjet recording excellent in storage stability and the like. Is disclosed.

JP, 2005-36202, A JP 2004-75988 A JP, 2011-94034, A JP, 2011-137102, A JP, 2011-144348, A

  An embodiment of the present invention aims to provide an aqueous dispersion of colored resin particles and an inkjet ink having excellent storage stability.

（式（１）において、Ｒ^１は水素原子又はメチル基を表し、Ｒ^２は水素原子、炭素数１〜１０のアルキル基、又は炭素数１〜９のアルキル基で置換されていてもよいフェニル基を表し、ＡＯはそれぞれ独立にエチレンオキシ基又はプロピレンオキシ基を表し、ｍは、エチレンオキシ基の平均付加モル数ｐ及びプロピレンオキシ基の平均付加モル数ｑの合計であり、４〜１００であり、ｐは１以上であり、ｑは０以上であり、＊は他の単位との結合部位を表す。）
本発明の他の実施形態により、上述の着色樹脂粒子の水分散体を含む、インクジェットインクが提供される。
本発明の他の実施形態により、揮発性有機溶剤、顔料、及び水不溶性酸性分散剤を含む顔料分散体と、少なくとも、下記式（１）で表される単位、疎水性単位、及び塩基性単位を含む水溶性ビニルポリマーとを混合し、前記水溶性ビニルポリマーが溶解した混合物Ａを得る工程、前記混合物Ａと、酸性乳化剤及び水を含む混合物Ｂとを混合し乳化して混合物Ｃを得る工程、及び、前記混合物Ｃから前記揮発性有機溶剤を除去する工程を含む、着色樹脂粒子の水分散体の製造方法が提供される。

（式（１）において、Ｒ^１は水素原子又はメチル基を表し、Ｒ^２は水素原子、炭素数１〜１０のアルキル基、又は炭素数１〜９のアルキル基で置換されていてもよいフェニル基を表し、ＡＯはそれぞれ独立にエチレンオキシ基又はプロピレンオキシ基を表し、ｍは、エチレンオキシ基の平均付加モル数ｐ及びプロピレンオキシ基の平均付加モル数ｑの合計であり、４〜１００であり、ｐは１以上であり、ｑは０以上であり、＊は他の単位との結合部位を表す。） According to an embodiment of the present invention, the resin composition contains colored resin particles, an acidic emulsifier, and water, and the colored resin particles include a pigment, a water-insoluble acidic dispersant, a unit represented by the following formula (1), and a hydrophobic property. Provided is an aqueous dispersion of colored resin particles, which comprises a unit and a water-soluble vinyl polymer containing a basic unit.

(In the formula (1), R ¹ represents a hydrogen atom or a methyl group, and R ² is a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, or phenyl optionally substituted with an alkyl group having 1 to 9 carbon atoms. Represents a group, AO independently represents an ethyleneoxy group or a propyleneoxy group, m is the sum of the average addition mole number p of the ethyleneoxy group and the average addition mole number q of the propyleneoxy group, and is 4 to 100. Yes, p is 1 or more, q is 0 or more, and * represents a binding site with another unit.)
According to another embodiment of the present invention, there is provided an inkjet ink including the aqueous dispersion of the colored resin particles described above.
According to another embodiment of the present invention, a pigment dispersion containing a volatile organic solvent, a pigment, and a water-insoluble acidic dispersant, and at least a unit represented by the following formula (1), a hydrophobic unit, and a basic unit. A mixture A containing a water-soluble vinyl polymer to obtain a mixture A in which the water-soluble vinyl polymer is dissolved, and a step of mixing the mixture A and a mixture B containing an acidic emulsifier and water to emulsify the mixture C. And a method for producing an aqueous dispersion of colored resin particles, which comprises a step of removing the volatile organic solvent from the mixture C.

(In the formula (1), R ¹ represents a hydrogen atom or a methyl group, and R ² is a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, or phenyl optionally substituted with an alkyl group having 1 to 9 carbon atoms. Represents a group, AO independently represents an ethyleneoxy group or a propyleneoxy group, m is the sum of the average addition mole number p of the ethyleneoxy group and the average addition mole number q of the propyleneoxy group, and is 4 to 100. Yes, p is 1 or more, q is 0 or more, and * represents a binding site with another unit.)

  According to the embodiments of the present invention, it is possible to provide an aqueous dispersion of colored resin particles and an inkjet ink having excellent storage stability.

  Hereinafter, the embodiments of the present invention will be described in detail, but it goes without saying that the present invention is not limited to these embodiments and various modifications and changes may be added.

<Aqueous dispersion of colored resin particles>
An aqueous dispersion of colored resin particles according to an embodiment of the present invention (hereinafter sometimes referred to as “colored resin particle dispersion”) contains colored resin particles, an acidic emulsifier, and water. , A pigment, a water-insoluble acidic dispersant, and a water-soluble vinyl polymer containing a unit represented by the following formula (1), a hydrophobic unit, and a basic unit (hereinafter sometimes referred to as “water-soluble vinyl polymer P”). .) And an aqueous dispersion of colored resin particles.

In the formula (1), R ¹ represents a hydrogen atom or a methyl group, and R ² is a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, or a phenyl group which may be substituted with an alkyl group having 1 to 9 carbon atoms. And AO independently represents an ethyleneoxy group or a propyleneoxy group, m is the sum of the average addition mole number p of the ethyleneoxy group and the average addition mole number q of the propyleneoxy group, and is 4 to 100. , P is 1 or more, q is 0 or more, and * represents a binding site with another unit.

According to this embodiment, an aqueous dispersion of colored resin particles having excellent storage stability can be provided.
Since the water-soluble vinyl polymer P contained in the colored resin particles is water-soluble, the pigment dispersibility can be improved. On the other hand, the water-soluble polymer tends to be easily separated from the pigment. However, since the water-soluble vinyl polymer P has a basic unit, it tends to have high pigment affinity. Further, since the basic unit of the water-soluble vinyl polymer P has a high affinity with the water-insoluble acidic dispersant, the affinity with the pigment can be further increased. Therefore, it is possible to make it difficult for the water-soluble vinyl polymer P to be separated from the surface of the pigment. Further, the hydrophobic unit of the water-soluble vinyl polymer P can further suppress the detachment of the water-soluble vinyl polymer P from the pigment surface due to the hydrophobic interaction. Furthermore, the steric repulsion by the alkyleneoxy chain contained in the unit represented by the formula (1) and the electrostatic repulsion force due to the charge of the acidic emulsifier can suppress the aggregation of the colored resin particles with each other. It is possible to reduce the aggregation of the colored resin particles generated during the production process. By these, the storage stability of the aqueous dispersion of the colored resin particles can be improved.
In addition, it is possible to reduce the aggregation of the colored resin particles generated during the production process, and since the emulsifying property is also good, it is also possible to reduce the proportion of coarse particles generated. The water dispersion has high productivity and can be efficiently manufactured.

  The colored resin particles can include a pigment.

  The pigment may be an organic pigment, an inorganic pigment or a combination thereof. If necessary, they may be used in combination with an extender pigment.

  Examples of organic pigments include azo pigments, disazo pigments, phthalocyanine pigments, quinacridone pigments, isoindolinone pigments, dioxazine pigments, perylene pigments, perinone pigments, thioindigo pigments, anthraquinone pigments, and quinophthalone pigments. These 1 type can be used individually or in combination of 2 or more types.

  Examples of the inorganic pigment include carbon black, metal oxides, metal sulfides, metal chlorides and the like, and one of these may be used alone, or two or more thereof may be used in combination. Of these, carbon black is particularly preferable.

  Examples of extender pigments include silica, calcium carbonate, talc, and the like, and one of these may be used alone, or two or more thereof may be used in combination.

The amount of pigment can be adjusted appropriately. For example, the amount of the pigment is preferably 30 to 80% by mass, more preferably 40 to 70% by mass, and further preferably 45 to 65% by mass, based on the total solid content of the colored resin particles.
The amount of the pigment is preferably 1 to 30% by mass, more preferably 3 to 20% by mass, and further preferably 5 to 15% by mass, based on the total amount of the colored resin particle dispersion.

The colored resin particles can include a water-insoluble acidic dispersant.
When the water-insoluble acidic dispersant is used, the pigment can be better dispersed in the production process of the colored resin particle dispersion. Further, the affinity between the water-insoluble acidic dispersant adsorbed on the pigment and the water-soluble vinyl polymer P having a basic unit makes it difficult to separate the water-soluble vinyl polymer P from the pigment surface.

  The amount of the water-insoluble acidic dispersant that can be dissolved in 9 g of water at 23 ° C. is preferably less than 1 g.

  The water-insoluble acidic dispersant has an acidic group.

  Examples of the acidic group of the water-insoluble acidic dispersant include a phosphoric acid group, a carboxy group, a sulfonic acid group, a phosphoric acid ester group, a sulfuric acid ester group, a nitric acid ester group, a phosphorous acid group, a phosphonic acid group, and a sulfinic acid group. be able to. The water-insoluble acidic dispersant may contain one type of acidic group in one molecule, or a combination of two or more types.

As the water-insoluble acidic dispersant, a water-insoluble acidic polymer dispersant is preferable.
The weight average molecular weight of the water-insoluble acidic dispersant is preferably 1,000 to 100,000, more preferably 2,000 to 50,000. The weight average molecular weight of the water-insoluble acidic dispersant is a value obtained by GPC method in terms of standard polystyrene.

  Examples of commercially available water-insoluble acidic dispersants include "SOLSPERSE 36000", "SOLSPERSE 36600", "SOLSPERSE 55000" (all are trade names) manufactured by Nippon Lubrizol Co., Ltd., and "DISPERBYK-106" manufactured by BYK Japan KK. "DISPERBYK-110", Kyoeisha Chemical Co., Ltd. "Floren G700" "Floren GW1500" etc. are mentioned.

  The water-insoluble acidic dispersants may be used alone or in combination of two or more.

The amount of the water-insoluble acidic dispersant can be appropriately adjusted.
For example, in a mass ratio, the water-insoluble acidic dispersant (solid content) may be blended in a proportion of 0.1 to 1, and preferably in a proportion of 0.2 to 1, with respect to the pigment 1. It is more preferable to mix it in a ratio of 0.2 to 0.6.

The amount (solid content) of the water-insoluble acidic dispersant is preferably from 1 to 50% by mass, more preferably from 5 to 40% by mass, even more preferably from 10 to 35% by mass, based on the total amount of the colored resin particle solid content. -30 mass% is more preferable.
The amount of the water-insoluble acidic dispersant is preferably 0.2 to 20% by mass, more preferably 0.5 to 15% by mass, and further preferably 1 to 10% by mass, based on the total amount of the colored resin particle dispersion.

  The colored resin particles may contain a water-soluble vinyl polymer (water-soluble vinyl polymer P) containing a unit represented by the formula (1), a hydrophobic unit, and a basic unit.

  It is preferable that 1 g or more of the water-soluble vinyl polymer P is dissolved in 9 g of water at 23 ° C.

  The unit represented by the formula (1) will be described.

In the formula (1), R ¹ represents a hydrogen atom or a methyl group, and R ² is a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, or a phenyl group which may be substituted with an alkyl group having 1 to 9 carbon atoms. And AO independently represents an ethyleneoxy group or a propyleneoxy group, m is the sum of the average addition mole number p of the ethyleneoxy group and the average addition mole number q of the propyleneoxy group, and is 4 to 100. , P is 1 or more, q is 0 or more, and * represents a binding site with another unit.

R ² is preferably a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a phenyl group which may be substituted with an alkyl group having 1 to 9 carbon atoms. R ² may be, for example, an alkyl group having 1 to 10 carbon atoms or 1 to 5 carbon atoms.

  AO is preferably an ethyleneoxy group.

  From the viewpoint of improving the hydrophilicity of the water-soluble vinyl polymer P, m is preferably 4 or more, more preferably 5 or more, further preferably 10 or more, and further preferably 20 or more. On the other hand, m is preferably 100 or less, more preferably 95 or less, further preferably 50 or less, more preferably 40 or less, and further preferably 30 or less from the viewpoint of easy handling. m is preferably 4 to 100, more preferably 5 to 100, further preferably 5 to 95, further preferably 10 to 50, further preferably 10 to 40, and further preferably 20 to 30.

  From the viewpoint of improving hydrophilicity, p is preferably 1 or more, more preferably 2 or more, further preferably 4 or more, further preferably 5 or more, further preferably 10 or more, and further preferably 20 or more. On the other hand, p is preferably 95 or less, more preferably 50 or less, further preferably 40 or less, and further preferably 30 or less, from the viewpoint of easy handling. p is preferably 1 or more, more preferably 1 to 95, further preferably 2 to 95, further preferably 4 to 95, further preferably 5 to 50, further preferably 5 to 40, further preferably 10 to 40, 20-30 is more preferable.

  q is preferably 10 or less, more preferably 5 or less, and further preferably 0.

  As the unit represented by the formula (1), a unit represented by the following formula (1-1) is preferable.

In the following formula (1-1), the definitions of R ¹ and R ² and their preferable ranges are the same as those in the formula (1). In the formula (1-1), m is the average number of moles of ethyleneoxy group added, which is 4 to 100, and the preferred range is the same as that of m in the formula (1). In Formula (1-1), * represents a binding site with another unit.

  As the unit represented by the formula (1), a unit derived from the monomer represented by the following formula (2) can be used.

In the following formula (2), the definitions of R ¹ , R ² , AO, and m and their preferable ranges are the same as those in the formula (1).

  As the monomer represented by the following formula (2), the monomer represented by the following formula (2-1) is preferable.

In the following formula (2-1), the definitions of R ¹ , R ² , and m and their preferable ranges are the same as those in the formula (1-1).

  Examples of the monomer represented by the formula (2) include polyethylene glycol mono (meth) acrylate, methoxy polyethylene glycol mono (meth) acrylate, octoxy polyethylene glycol mono (meth) acrylate, stearoxy polyethylene glycol mono (meth) acrylate, and the like. Is mentioned. Examples of commercially available products of the monomer represented by the formula (2) include NK ester M-230G (trade name) manufactured by Shin-Nakamura Chemical Co., Ltd., Bremmer PME-1000 and Bremmer PME-4000 manufactured by NOF Corporation. Bremmer PME-400 (all are trade names), Kyoeisha Chemical Co., Ltd. light ester 041MA (trade name) and the like can be mentioned. The (meth) acrylate means both methacrylate and acrylate. The same applies to the following.

  The water-soluble vinyl polymer P may contain the unit represented by Formula (1) individually by 1 type or in combination of 2 or more types.

  From the viewpoint of improving the hydrophilicity of the water-soluble vinyl polymer P, the unit represented by the formula (1) is preferably more than 15 mol% and more preferably 18 mol% or more based on the total units of the water-soluble vinyl polymer P. 20 mol% or more is more preferable. On the other hand, the unit represented by the formula (1) is more preferably 55 mol% or less, more preferably 50 mol% or less, and further preferably 45 mol% or less, based on all the units of the water-soluble vinyl polymer P. The unit represented by the formula (1) is, for example, more than 15 mol% and 55 mol% or less, preferably 18 to 55 mol%, more preferably 20 to 50 mol% based on all the units of the water-soluble vinyl polymer P. Is more preferable, and 20 to 45 mol% is further preferable.

  The basic unit will be described.

  The basic unit preferably has a basic group such as an amino group, an amide group, a pyridyl group, an imino group and a pyrrolidone group. Especially, it is preferable to have an amino group. The amino group is preferably an amino group substituted with an alkyl group, and the carbon number of the alkyl group is preferably 1 to 10, preferably 1 to 5, more preferably 1 to 3, and even more preferably 1. Examples of the amino group include a diethylamino group and a dimethylamino group. As the basic group, a dimethylamino group is preferable.

Examples of the basic unit include N, N-dimethylaminoethyl (meth) acrylate, N, N-dimethylaminopropyl (meth) acrylate, N, N-dimethylaminopropyl (meth) acrylamide, N, N-dimethylaryl. Examples thereof include units derived from basic monomers such as amine and N, N-diethylaminoethyl (meth) acrylate, and the basic monomer is preferably N, N-dimethylaminoethyl (meth) acrylate.
The basic monomer preferably has a basic group such as an amino group, an amide group, a pyridyl group, an imino group and a pyrrolidone group, and the preferable range of the basic group is the same as that of the basic unit.

  The water-soluble vinyl polymer (A) may contain one basic unit or a combination of two or more basic units.

  From the viewpoint of improving the pigment affinity of the water-soluble vinyl polymer P, the basic unit is preferably 15 mol% or more, more preferably 20 mol% or more, and 30 mol% or more, based on all the units of the water-soluble vinyl polymer P. Is more preferable. On the other hand, the basic unit is preferably 60 mol% or less, more preferably 55 mol% or less, still more preferably 50 mol% or less, based on all the units of the water-soluble vinyl polymer P. The basic unit is, for example, preferably 15 to 60 mol%, more preferably 15 to 55 mol%, further preferably 20 to 50 mol%, and further preferably 30 to 50 mol% based on all the units of the water-soluble vinyl polymer P. Is more preferable.

  The hydrophobic unit will be described.

Examples of the hydrophobic unit include units derived from a hydrophobic monomer such as (meth) acrylic acid ester, an aromatic ring-containing monomer, and a macromer. As the hydrophobic monomer, (meth) acrylic acid ester is preferable. In addition, (meth) acrylic acid ester means both a methacrylic acid ester and an acrylyl acid ester.
The water-soluble vinyl polymer (A) may contain a hydrophobic unit singly or in combination of two or more.

  As the (meth) acrylic acid ester, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate (for example, n- or isopropyl (meth) acrylate), butyl (meth) acrylate (for example, n-, Iso or tertiary butyl (meth) acrylate), amyl (meth) acrylate (for example, n- or isoamyl (meth) acrylate), cyclohexyl (meth) acrylate, benzyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, octyl (Meth) acrylate (for example, n- or isooctyl (meth) acrylate), decyl (meth) acrylate (for example, n- or isodecyl (meth) acrylate), dodecyl (meth) acrylate (for example, n- or isododecyl) (Meth) acrylate), stearyl (meth) acrylate (e.g., n- or isostearyl (meth) (meth) acrylic acid esters having an alkyl group having 1 to 18 carbon atoms such as acrylates) can be mentioned. The water-soluble vinyl polymer (A) may contain these individually by 1 type or in combination of 2 or more types.

  Since the hydrophobic unit enhances the hydrophobic interaction of the water-soluble vinyl polymer P and positions the water-soluble polymer P around the pigment, it is preferably 20 mol% or more based on all units of the water-soluble vinyl polymer P, 25 It is more preferably at least mol%. On the other hand, the hydrophobic unit is preferably 60 mol% or less, more preferably 55 mol% or less, still more preferably 50 mol% or less, based on all the units of the water-soluble vinyl polymer P. The hydrophobic unit is, for example, preferably 20 to 60 mol%, more preferably 20 to 55 mol%, still more preferably 25 to 50 mol%, based on all the units of the water-soluble vinyl polymer P.

  The water-soluble vinyl polymer P may contain other units.

  The water-soluble vinyl polymer P may be, for example, a water-soluble vinyl polymer obtained by polymerizing a monomer mixture containing a monomer represented by the formula (2), a basic monomer, and a hydrophobic monomer. The above-mentioned thing can be used as a monomer represented by Formula (2), a basic monomer, and a hydrophobic monomer. The monomer mixture may contain the monomer represented by the formula (2), the basic monomer, and the hydrophobic monomer independently, or in combination of two or more kinds. The blending amount of each monomer in the monomer mixture can be adjusted, for example, so as to be a preferable ratio of each unit described above.

The method for producing the water-soluble vinyl polymer P is not particularly limited. For example, it can be produced by polymerizing the monomer composition by a known polymerization method such as a bulk polymerization method, a solution polymerization method, a suspension polymerization method or an emulsion polymerization method. Of these polymerization methods, bulk polymerization or solution polymerization is preferable.
As the monomer composition, for example, a composition containing a monomer mixture containing a monomer represented by the formula (2), a basic monomer, and a hydrophobic monomer can be used. The monomer represented by formula (2), the basic monomer, and the hydrophobic monomer are as described above. The monomer represented by the formula (2), the basic monomer, and the hydrophobic monomer can be used alone or in combination of two or more kinds.
The blending amount of each monomer in the monomer composition can be adjusted, for example, so as to be a preferable ratio of each unit described above.

The solvent used in the solution polymerization method is preferably a polar organic solvent.
Examples of the polar organic solvent include aliphatic alcohols having 1 to 3 carbon atoms such as ethanol and propanol; ketones such as acetone and methyl ethyl ketone; esters such as ethyl acetate.

A radical polymerization initiator can be used during the polymerization. As the radical polymerization initiator, 2,2'-azobisisobutyronitrile, 2,2'-azobis (2,4-dimethylvaleronitrile), dimethyl-2,2'-azobisbutyrate, 2,2 ' Azo compounds such as'-azobis (2-methylbutyronitrile) and 1,1'-azobis (1-cyclohexanecarbonitrile) are preferable. Further, organic peroxides such as t-butyl peroxyoctoate, di-t-butyl peroxide, dibenzoyl oxide and the like can also be used.
The amount of the polymerization initiator is preferably 0.001 to 5 mol, more preferably 0.01 to 2 mol, per mol of the monomer mixture.

  During the polymerization, a polymerization chain transfer agent and / or RAFT agent may be further added. Specific examples of the polymerization chain transfer agent include mercaptans such as octyl mercaptan, n-dodecyl mercaptan, t-dodecyl mercaptan, n-tetradecyl mercaptan and 2-mercaptoethanol; xanthogen disulfides such as dimethylxanthogen disulfide and diisopropylxanthogendisulfide. Thiuram disulfides such as tetramethyl thiuram disulfide and tetrabutyl thiuram disulfide; halogenated hydrocarbons such as carbon tetrachloride and ethylene bromide; hydrocarbons such as pentaphenylethane; acrolein, methacrolein, allyl alcohol, 2- Ethylhexyl thioglycolate, terbinolene, α-terpinene, γ-terpinene, dipentene, α-methylstyrene dimer, 9,10-dihydroanthracene, , 4-dihydronaphthalene, indene, 1,4-cyclohexadiene unsaturated cyclic hydrocarbon compounds of a diene and the like; 2,5-unsaturated heterocyclic compounds dihydrofuran like, and the like.

The polymerization conditions differ depending on the type of radical polymerization initiator, monomer, solvent, etc. used.
Usually, the polymerization temperature is preferably 30 to 100 ° C., more preferably 50 to 80 ° C., and the polymerization time is preferably 1 to 20 hours. The polymerization atmosphere is preferably an inert gas atmosphere such as nitrogen gas or argon.
In the case of bulk polymerization, the same reaction as in solution polymerization may be carried out except that the reaction is carried out without a solvent. The polymerization conditions may be the same as the solution polymerization.

The weight average molecular weight Mw of the water-soluble vinyl polymer P is preferably about 5,000 to 100,000, more preferably 5,000 to 50,000.
The number average molecular weight Mn of the water-soluble vinyl polymer P is preferably about 3,000 to 100,000, more preferably 4,000 to 50,000.
The molecular weight distribution Mw / Mn of the water-soluble vinyl polymer P is preferably 1.0 to 2.0.
Both the weight average molecular weight and the number average molecular weight are values obtained by GPC method in terms of standard polystyrene.

The amount of the water-soluble vinyl polymer P can be adjusted appropriately.
For example, in terms of mass ratio, the water-soluble vinyl polymer may be blended in a ratio of 0.1 to 1 with respect to the pigment 1, preferably 0.2 to 1 and more preferably 0.2 to 0. It is more preferable to mix them in a ratio of 0.6.
The amount of the water-soluble vinyl polymer P is preferably 1 to 50% by mass, more preferably 5 to 40% by mass, further preferably 10 to 35% by mass, and 15 to 30% by mass based on the total solid content of the colored resin particles. Is more preferable.
The amount of the water-soluble vinyl polymer P is preferably 0.2 to 20% by mass, more preferably 0.5 to 15% by mass, and further preferably 1 to 10% by mass, based on the total amount of the colored resin particle dispersion.

  The aqueous dispersion of colored resin particles can include an acidic emulsifier. The acidic emulsifier can satisfactorily disperse the colored resin particles in water.

The acidic emulsifier has an acidic group.
Examples of the acidic group of the acidic emulsifier include a phosphoric acid group, a carboxy group, a sulfonic acid group, a phosphoric acid ester group, a sulfuric acid ester group, a nitric acid ester group, a phosphorous acid group, a phosphonic acid group, and a sulfinic acid group. .. The acidic emulsifier may contain one type of acidic group in one molecule or a combination of two or more types.

The acidic emulsifier is preferably water-soluble.
It is preferable that 1 g or more of the acidic emulsifier be dissolved in 9 g of water at 23 ° C.

The acidic emulsifier preferably contains an ethyleneoxy chain, and more preferably has an acidic group bonded to the end of the ethyleneoxy chain.
Examples of such acidic emulsifiers include compounds represented by the following formula (3).

In the formula (3), R represents a monovalent organic group, preferably an alkyl group or an aryl group, and more preferably an alkyl group, a phenyl group or a polycyclic phenyl group. n is 1 or more. X represents Na or NH ₄ .

  Examples of commercially available acidic emulsifiers include “Newcol 707SN” (polyoxyethylene polycyclic phenyl ether sulfate salt) manufactured by Nippon Emulsifier Co., Ltd., “Hitenol 08E” (polyoxyethylene oleyl) manufactured by Daiichi Kogyo Seiyaku Co., Ltd. (Sulfate ester salt) and the like.

The amount of acidic emulsifier can be adjusted appropriately.
For example, in terms of mass ratio, the acidic emulsifier (solid content) may be blended in a proportion of 0.05 to 2, and preferably in a proportion of 0.05 to 1, with respect to pigment 1. It is more preferable to mix them in a ratio of 0.5.
The amount of the acidic emulsifier is preferably 0.1 to 10% by mass, more preferably 0.5 to 7% by mass, and further preferably 1 to 5% by mass based on the total amount of the colored resin particle dispersion.

The aqueous dispersion of colored resin particles can contain water.
As water, tap water, ion-exchanged water, deionized water or the like can be used.

The amount of water can be adjusted appropriately.
The amount of water is preferably 60 to 99% by mass, more preferably 65 to 95% by mass, and even more preferably 70 to 90% by mass, based on the total amount of the colored resin particle dispersion.

  In addition to the above components, the colored resin particle dispersion may contain various additives and the like as necessary.

The average particle diameter of the colored resin particles in the colored resin particle dispersion is preferably 50 to 300 nm, more preferably 80 to 200 nm.
The average particle size of the colored resin particles is a volume-based average particle size based on a dynamic scattering method, and for example, using a dynamic light scattering particle size distribution analyzer “LB-500” manufactured by Horiba Ltd. Can be measured.

  The amount of the colored resin particles in the colored resin particle dispersion is preferably 1 to 30% by mass, more preferably 3 to 25% by mass, as the amount of the solid content of the colored resin particle component with respect to the total amount of the colored resin particle dispersion. -20 mass% is more preferred.

  The method for producing the colored resin particle dispersion is not particularly limited, but it can be preferably produced using the method for producing the colored resin particle dispersion described below.

The inkjet ink of the embodiment (hereinafter, may be simply referred to as “ink”) includes the above-mentioned aqueous dispersion of colored resin particles. This inkjet ink has excellent storage stability. In addition, it has high productivity and can be manufactured efficiently.
In the inkjet ink, the colored resin particle dispersion may be used as it is, and if necessary, a water-soluble organic solvent, a surfactant and the like may be added.

  As the water-soluble organic solvent, an organic compound that is liquid at room temperature and soluble in water can be used from the viewpoint of viscosity adjustment and moisturizing effect, and can be uniformly mixed with the same volume of water at 1 atmospheric pressure and 20 ° C. It is preferable to use a water-soluble organic solvent. For example, glycols such as ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol and polypropylene glycol; glycerin such as glycerin, diglycerin, triglycerin and polyglycerin. Acetins such as monoacetin and diacetin; ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monopropyl ether, diethylene glycol monobutyl ether Triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, triethylene glycol monopropyl ether, triethylene glycol monobutyl ether, tetraethylene glycol monomethyl ether, tetraethylene glycol monoethyl ether, tetraethylene glycol dimethyl ether, tetraethylene glycol diethyl ether, etc. 1-methyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, β-thiodiglycol, sulfolane and the like can be used. The boiling point of the water-soluble organic solvent is preferably 100 ° C or higher, more preferably 150 ° C or higher, and even more preferably 200 ° C or higher.

  The surfactant is not particularly limited, but for example, acetylene glycol-based surfactant, polyoxyethylene alkylphenol, polyoxyethylene alkyl ether, polyoxyethylene fatty acid ester and the like are preferable. Examples of the acetylene glycol-based surfactant include Surfynol 465 manufactured by Nisshin Chemical Industry Co., Ltd. and the like.

  For the average particle diameter of the colored resin particles in the ink, and the preferable range of the amount of the colored resin particles in the ink, the average particle diameter of the colored resin particles in the colored resin particle dispersion described above, and in the colored resin particle dispersion It is the same as the amount of the colored resin particles.

The amount of pigment in the ink is preferably 1 to 20% by mass, more preferably 3 to 15% by mass, and even more preferably 5 to 13% by mass, based on the total amount of the ink.
The amount of the water-insoluble acidic dispersant in the ink is preferably 0.2 to 20% by mass, more preferably 0.5 to 15% by mass, and even more preferably 1 to 10% by mass, based on the total amount of the ink.
The amount of the water-soluble vinyl polymer P in the ink is preferably 0.2 to 20% by mass, more preferably 0.5 to 15% by mass, and further preferably 1 to 10% by mass, based on the total amount of the ink.
The amount of the acidic emulsifier in the ink is preferably 0.1 to 10% by mass, more preferably 0.5 to 7% by mass, and even more preferably 1 to 5% by mass, based on the total amount of the ink.
The amount of water in the ink is preferably 60 to 99% by mass, more preferably 65 to 95% by mass, and even more preferably 70 to 90% by mass with respect to the total amount of the ink.

  The suitable range of the viscosity of the inkjet ink varies depending on the nozzle diameter of the ejection head of the inkjet recording system, the ejection environment, etc., but generally it is preferably 5 to 30 mPa · s at 23 ° C., and 5 to 15 mPa · s. Is more preferable.

  The printing method using the inkjet ink is not particularly limited, and may be any method such as a piezo method, an electrostatic method, and a thermal method. When an inkjet recording apparatus is used, it is preferable that the ink according to the present embodiment is ejected from the inkjet head based on a digital signal and the ejected ink droplets are attached to the recording medium.

  In the present embodiment, the recording medium is not particularly limited, and printing paper such as plain paper, coated paper, and special paper, cloth, inorganic sheet, film, OHP sheet, and the like, and an adhesive layer on the back surface using these as a base material It is possible to use an adhesive sheet or the like provided with.

  Here, the plain paper is a paper on which an ink receiving layer, a film layer, or the like is not formed on a normal paper. Examples of plain paper include high-quality paper, medium-quality paper, PPC paper, waste paper, recycled paper, and the like.

  Further, as the coated paper, inkjet coated paper such as matte paper, glossy paper, semi-glossy paper, and so-called coated printing paper can be preferably used. Here, the coated printing paper is a printing paper that has been conventionally used in letterpress printing, offset printing, gravure printing, etc., and with an inorganic pigment such as clay or calcium carbonate on the surface of high-quality paper or medium-quality paper. , A printing paper provided with a coating layer made of a paint containing a binder such as starch. Depending on the coating amount and coating method, coated printing paper can be fine coated paper, fine lightweight coated paper, medium lightweight coated paper, fine coated paper, medium coated paper, art paper, cast coated paper, etc. being classified.

  <Method for producing aqueous dispersion of colored resin particles>

  A method for producing an aqueous dispersion of colored resin particles according to one embodiment includes a pigment dispersion containing a volatile organic solvent, a pigment, and a water-insoluble acidic dispersant, and at least a unit represented by the following formula (1): Of a water-soluble vinyl polymer containing a hydrophilic unit and a basic unit to obtain a mixture A in which the water-soluble vinyl polymer is dissolved (hereinafter, sometimes referred to as "step 1"), mixture A and an acidic emulsifier And a mixture B containing water and emulsified to obtain a mixture C (hereinafter, sometimes referred to as “step 2”), and a step of removing the volatile organic solvent from the mixture C (hereinafter, “step”). 3) ”is also included.

In the formula (1), R ¹ represents a hydrogen atom or a methyl group, and R ² is a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, or a phenyl group which may be substituted with an alkyl group having 1 to 9 carbon atoms. And AO independently represents an ethyleneoxy group or a propyleneoxy group, m is the sum of the average addition mole number p of the ethyleneoxy group and the average addition mole number q of the propyleneoxy group, and is 4 to 100. , P is 1 or more, q is 0 or more, and * represents a binding site with another unit.

  By this method, an aqueous dispersion of colored resin particles having excellent storage stability can be produced. In addition, this method has high productivity and can efficiently produce an aqueous dispersion of colored resin particles.

  The pigment, water-insoluble acidic dispersant, water-soluble vinyl polymer P, acidic emulsifier, and water are as described above, and the preferable range of the amount of each component in the obtained colored resin particle dispersion is also as described above. It is the same as the colored resin particle dispersion.

A water-soluble vinyl polymer is prepared by mixing a pigment dispersion containing a volatile organic solvent, a pigment, and a water-insoluble acidic dispersant (hereinafter sometimes referred to as “pigment dispersion D”) and at least a water-soluble vinyl polymer P. The step of obtaining the mixture A in which is dissolved (“Step 1”) will be described.
A pigment dispersion containing a volatile organic solvent, a pigment, and a water-insoluble acidic dispersant is, for example, a pigment and a water-insoluble acidic dispersant are mixed in a volatile organic solvent and dispersed using a disperser such as a bead mill. It can be obtained. In this way, a pigment dispersion in which the pigment is dispersed in the volatile organic solvent with the water-insoluble acidic dispersant can be prepared.
The pigment dispersion D is preferably dispersed so that the average particle diameter of the pigment is about 10 nm to 200 nm.
The average particle size of the pigment is a volume-based average particle size based on the dynamic scattering method, and is measured using, for example, a dynamic light scattering particle size distribution measuring device “LB-500” manufactured by Horiba, Ltd. be able to.

The volatile organic solvent used for the pigment dispersion D is preferably a volatile polar organic solvent.
The boiling point of the volatile organic solvent used in the pigment dispersion D is preferably 100 ° C. or lower, more preferably 40 to 90 ° C., and further preferably 50 to 80 ° C.

  Examples of the volatile polar organic solvent include ethanol, isopropanol, n-butanol, tertiary butanol, isobutanol, acetone, methyl ethyl ketone, diethyl ketone, methyl isobutyl ketone, dibutyl ether, tetrahydrofuran, dioxane, ethyl acetate, butyl acetate, etc. Can be given.

  The amount of the pigment in the pigment dispersion D is preferably 1 to 50% by mass, more preferably 5 to 40% by mass, and even more preferably 10 to 30% by mass based on the total amount of the pigment dispersion D. The amount of the water-insoluble acidic dispersant in the pigment dispersion D is preferably 0.1 to 30% by mass, more preferably 1 to 20% by mass, based on the total amount D of the pigment dispersion. The amount of the volatile organic solvent in the pigment dispersion D is preferably 30 to 95% by mass, more preferably 40 to 90% by mass, and further preferably 50 to 80% by mass, based on the total amount of the pigment dispersion D.

In step 1, the pigment dispersion D and at least the water-soluble vinyl polymer P are mixed, but, for example, a volatile organic solvent or the like may be further mixed. For example, it is preferable to mix a polymer solution in which a water-soluble vinyl polymer P is dissolved in a volatile organic solvent (hereinafter sometimes referred to as polymer solution S) and the pigment dispersion D. As the volatile organic solvent used here, for example, the same volatile organic solvent as that which can be used for the pigment dispersion D can be selected and used, but the same volatile organic solvent contained in the pigment dispersion D is used. Preferably.
In this way, the mixture A having the water-soluble vinyl polymer P dissolved therein can be obtained.

  The amount of the pigment in the mixture A is preferably 1 to 40% by mass, more preferably 5 to 30% by mass, and even more preferably 10 to 20% by mass based on the total amount of the mixture A. The amount of the water-insoluble acidic dispersant in the mixture A is preferably 0.1 to 20% by mass, more preferably 1 to 10% by mass, based on the total amount of the mixture A. The amount of the water-soluble vinyl polymer P in the mixture A is preferably 0.1 to 20% by mass, more preferably 1 to 10% by mass, based on the total amount of the mixture A. The amount of the volatile organic solvent in the mixture A is preferably 40 to 90% by mass, more preferably 50 to 80% by mass, based on the total amount of the mixture A.

The step (“step 2”) of mixing the mixture A and the mixture B containing the acidic emulsifier and water and emulsifying the mixture to obtain the mixture C will be described.
In step 2, it is preferable to add the mixture A obtained in step 1 to the mixture B containing the acidic emulsifier and water while stirring and emulsify it using an ultrasonic emulsifying machine or the like.

  0.1-20 mass% is preferable, and, as for the quantity of the acidic emulsifier in the mixture B, 1-10 mass% is more preferable. The amount of water in the mixture B is preferably 70 to 99% by mass, more preferably 75 to 95% by mass.

  The mixing ratio of the mixture A and the mixture B is preferably 1: 0.5 to 2 by mass ratio (A: B), more preferably 1: 0.8 to 1.5, and 1: 1 to 1.2. Is more preferable.

The step of removing the volatile organic solvent from the mixture C (“step 3”) will be described.
In step 3, the volatile organic solvent contained in mixture A is removed from mixture C obtained in step 2. This makes it possible to obtain colored resin particles from which the volatile organic solvent has been removed from the mixture A component.

Examples of the method for removing the volatile organic solvent include reducing pressure and / or heating. As the conditions of depressurization and / or heating, conditions under which the volatile organic solvent contained in the mixture C is removed can be adopted, but conditions under which water is not removed are preferred. An evaporator, for example, can be used for the depressurization. The heating temperature is preferably 40 to 90 ° C, more preferably 50 to 80 ° C.
In step 3, the volatile organic solvent is preferably removed in an amount of 95% by mass or more, and more preferably 97% by mass or more, based on the amount before the removal.
In step 3, a part of water may be further removed.

  The method for producing an aqueous dispersion of colored resin particles may include other steps. For example, after step 3, a step of adding an additive or the like may be further performed.

  Hereinafter, the present invention will be described in detail with reference to Examples, but the present invention is not limited thereto. Unless otherwise specified, “%” indicates “mass%”.

1. Preparation of Vinyl Polymers and Polymer Solutions Tables 1-3 show the materials and amounts used to synthesize vinyl polymers 1-10.
The materials shown in Tables 1 to 3 were placed in a flask and heated and stirred at 70 ° C. for 14 hours under a nitrogen atmosphere. The unit of the blending amount of each material shown in Tables 1 to 3 is “g”.

Details of the materials described in Tables 1 to 3 are shown below.
Monomer A1: Bremmer PME1000 (methoxy polyethylene glycol methacrylate, EO addition mole number 23, NOF Corporation)
Monomer A2: Bremmer PME400 (methoxy polyethylene glycol methacrylate, EO addition mole number 9, manufactured by NOF CORPORATION)
Monomer A3: Bremmer PME4000 (methoxy polyethylene glycol methacrylate, EO addition mole number 90, manufactured by NOF CORPORATION)
Monomer B1: Dimethylaminoethyl methacrylate (manufactured by FUJIFILM Wako Pure Chemical Industries, Ltd.)
Monomer B2: Diethylaminoethyl methacrylate (manufactured by FUJIFILM Wako Pure Chemical Industries, Ltd.)
Monomer B3: Methacrylic acid (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.)
Monomer C1: benzyl methacrylate (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.)
Monomer C2: Butyl methacrylate (manufactured by FUJIFILM Wako Pure Chemical Industries, Ltd.)
Monomer C3: 2-ethylhexyl methacrylate (Fuji Film Wako Pure Chemical Industries, Ltd.)
RAFT agent: RAFT723037 (molecular weight 345, manufactured by Aldrich)
Chain transfer agent: Lauryl mercaptan (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.)
Initiator: AIBN (2,2-azobisisobutyronitrile, molecular weight 164, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.)

  The weight average molecular weight Mw, the number average molecular weight Mn, and the molecular weight distribution Mw / Mn of the obtained vinyl polymers 1 to 7 and the solubility of the obtained vinyl polymers 1 to 10 in water are shown in Tables 1 and 2.

  The weight average molecular weight Mw and the number average molecular weight Mn are values obtained by GPC method in terms of standard polystyrene.

  The solubility in water was evaluated as follows. 1 g of vinyl polymer and 9 g of water were placed in a sample bottle, and it was observed at 23 ° C. whether or not the vinyl polymer was completely dissolved. A was “completely dissolved” and C was “not completely dissolved”. ..

  As shown in Tables 1 to 3, the vinyl polymers 1 to 6 and 8 to 10 had water solubility A, and the vinyl polymer 7 had water solubility C.

  Ethyl acetate (manufactured by FUJIFILM Wako Pure Chemical Industries, Ltd.) was added to the vinyl polymers 1 to 10 to prepare 30% by mass ethyl acetate solutions of the vinyl polymers 1 to 10 to be polymer solutions 1 to 10.

2. Preparation of pigment dispersion Pigment dispersion 1
35 g of carbon black MA7 (manufactured by Mitsubishi Chemical Co., Ltd.), 30 g of Solsperse 55000 (50% by mass solution of methoxypropyl acetate as an acidic comb dispersant, manufactured by Nippon Lubrizol Co., Ltd.), and ethyl acetate (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) ) 110 g was mixed by a bead mill to obtain a pigment dispersion 1.
The volume-based average particle diameter of the pigment dispersion 1 by the dynamic scattering method was 122.2 nm. The volume-based average particle size according to the dynamic scattering method was measured using a dynamic light scattering particle size distribution analyzer “LB-500” manufactured by Horiba Ltd. (hereinafter the same).

Pigment dispersion 2
35 g of carbon black MA7 (manufactured by Mitsubishi Chemical Co., Ltd.), 15 g of SMA1440 (styrene maleic acid resin, manufactured by CRAVY Valley USA, LLC), and 125 g of ethyl acetate (manufactured by FUJIFILM Wako Pure Chemical Industries, Ltd.) are mixed with a bead mill to disperse the pigment. I got body 2.
The volume-based average particle diameter of the pigment dispersion 2 by the dynamic scattering method was 124.6 nm.

Pigment dispersion 3
35 g of carbon black MA7 (manufactured by Mitsubishi Chemical Co., Ltd.), 15 g of Sols Perth 32000 (basic dispersant, manufactured by Nippon Lubrizol Co., Ltd.), and 125 g of ethyl acetate (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) were mixed with a bead mill to prepare a pigment. Dispersion 3 was obtained.
The volume-based average particle diameter of the pigment dispersion 3 by the dynamic scattering method was 126.4 nm.

3. Preparation of Aqueous Dispersion of Colored Resin Particles The pigment dispersion and the polymer solution were mixed in the amounts shown in Tables 4 to 6 to prepare an oil phase. Further, an emulsifier and water were mixed in the amounts shown in Tables 4 to 6 to prepare an aqueous phase.
The oil phase was added to the aqueous phase while stirring and emulsified with an ultrasonic emulsifier "VC-750" (manufactured by SONIC). After emulsification, ethyl acetate was removed by an evaporator.
Next, a centrifugal separator was used to remove coarse particles and the like at 20,000 G for 6 minutes to prepare an aqueous dispersion of the colored resin particles of each Example and Comparative Example.

Details of the materials described in Tables 4 to 6 are as follows. The unit of the blending amount of each material shown in Tables 4 to 6 is "g".
Pigment dispersions 1-3: produced as above Polymer solutions 1-10: produced as above (solid content 30% by mass)
Emulsifier 1: Newcol 707SN (polyoxyethylene polycyclic phenyl ether sulfate salt (acidic emulsifier), active ingredient 30% by mass, manufactured by Nippon Emulsifier Co., Ltd.)
Emulsifier 2: Hitenol 08E (polyoxyethylene oleyl sulfate ester salt (acidic emulsifier), active ingredient more than 95% by mass, manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.)
Emulsifier 3: BC-20 (polyoxyethylene cetyl ether, manufactured by Nikko Chemicals Co., Ltd.)

4. Evaluation of aqueous dispersion of colored resin particles <Storage stability of aqueous dispersion of colored resin particles>
The storage stability was evaluated for the aqueous dispersions of the colored resin particles of each Example and Comparative Example.
First, the viscosity of the colored resin particles immediately after production was measured.
Next, the aqueous dispersion of the colored resin particles was put in a closed container and left at 70 ° C. for 4 weeks. Then, the aqueous dispersion of the colored resin particles was sampled, and the viscosity of the aqueous dispersion of the colored resin particles was measured.
The viscosity of the aqueous dispersion of the colored resin particles is a viscosity at 23 ° C., and was measured with a rheometer AR-G2 (manufactured by TA Instruments Japan Co., Ltd.) at a cone angle of 2 ° and a diameter of 40 mm. ..
From the viscosity of the aqueous dispersion of the colored resin particles immediately after preparation and the viscosity of the aqueous dispersion of the colored resin particles after standing for 4 weeks, the viscosity change rate was calculated by the following formula, and the storage stability was evaluated according to the following criteria.
Viscosity change rate (%) = [(viscosity of water dispersion of colored resin particles after standing for 4 weeks × 100) / (viscosity of water dispersion of colored resin particles immediately after production)]-100 (%)
The evaluation results are shown in the table.
(Evaluation criteria)
AA: Viscosity change rate is less than 5% A: Viscosity change rate is 5% or more and less than 7% B: Viscosity change rate is 7% or more and less than 10% C: Viscosity change rate is 10% or more

  It was shown that the aqueous dispersions of colored resin particles of each example have excellent storage stability.

5. Preparation and Evaluation of Inkjet Ink 8.0 g of an aqueous dispersion of colored resin particles of Example 1, 2.0 g of glycerin (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.), 1.0 g of water, Surfynol 465 (acetylene glycol-based surfactant) 0.5 g of the agent, manufactured by Nissin Chemical Industry Co., Ltd.) was mixed to prepare an inkjet ink.
The produced inkjet ink was subjected to inkjet printing using an inkjet printer "Calario Me PF-71" (manufactured by Seiko Epson Corporation), and a clean printed image was obtained.

Claims (7)

Contains colored resin particles, an acidic emulsifier, and water,
The colored resin particles include a pigment, a water-insoluble acidic dispersant, and a water-soluble vinyl polymer containing a unit represented by the following formula (1), a hydrophobic unit, and a basic unit:
Aqueous dispersion of colored resin particles.

(In the formula (1), R ¹ represents a hydrogen atom or a methyl group, and R ² is a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, or phenyl optionally substituted with an alkyl group having 1 to 9 carbon atoms. Represents a group, AO independently represents an ethyleneoxy group or a propyleneoxy group, m is the sum of the average addition mole number p of the ethyleneoxy group and the average addition mole number q of the propyleneoxy group, and is 4 to 100. Yes, p is 1 or more, q is 0 or more, and * represents a binding site with another unit.)   The aqueous dispersion of colored resin particles according to claim 1, wherein m is 10 to 50 in the unit represented by the formula (1) of the water-soluble vinyl polymer.   The aqueous dispersion of colored resin particles according to claim 1, wherein in the unit represented by the formula (1) of the water-soluble vinyl polymer, AO is an ethyleneoxy group.   The aqueous dispersion of colored resin particles according to claim 1, wherein the basic unit of the water-soluble vinyl polymer has a dimethylamino group.   The aqueous dispersion of colored resin particles according to any one of claims 1 to 4, wherein the acidic emulsifier contains an ethyleneoxy chain and an acidic group bonded to a terminal of the ethyleneoxy chain.   An inkjet ink comprising the aqueous dispersion of the colored resin particles according to claim 1. A pigment dispersion containing a volatile organic solvent, a pigment, and a water-insoluble acidic dispersant, and a water-soluble vinyl polymer containing at least a unit represented by the following formula (1), a hydrophobic unit, and a basic unit are mixed. And obtaining a mixture A in which the water-soluble vinyl polymer is dissolved,
Mixing the mixture A with a mixture B containing an acidic emulsifier and water and emulsifying the mixture to obtain a mixture C; and
Including removing the volatile organic solvent from the mixture C,
A method for producing an aqueous dispersion of colored resin particles.

(In the formula (1), R ¹ represents a hydrogen atom or a methyl group, and R ² is a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, or phenyl optionally substituted with an alkyl group having 1 to 9 carbon atoms. Represents a group, AO independently represents an ethyleneoxy group or a propyleneoxy group, m is the sum of the average addition mole number p of the ethyleneoxy group and the average addition mole number q of the propyleneoxy group, and is 4 to 100. Yes, p is 1 or more, q is 0 or more, and * represents a binding site with another unit.)