JP2003113327A - Microcapsulated colorant dispersion and aqueous ink composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an aqueous ink composition which has excellent dispersibility in a water system, high printing density and printing quality, quick-drying properties, excellent abrading resistance, fixing properties and yet can provide a recorded article having excellent water resistance and light resistance and chemical resistance. SOLUTION: This aqueous ink composition comprises a microcapsulated colorant obtained by dispersing a water-insoluble colorant in the presence of a polymer azo initiator containing a repeating unit represented by general formula (I) [D is a part containing a hydrophobic segment; L<1> and L<2> are each the same or different linker group; R<1> , R<2> , R<3> and R<4> are each a 1-4C alkyl group or a cyano group; n is an integer of >=1] and a vinyl-based polymerizable dispersant under conditions not to activate the initiator and activating the initiator in the resulting dispersion to polymerize the polymerizable dispersant.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an aqueous dispersion and an aqueous ink composition containing a microencapsulated colorant. According to the present invention, an ink jet that can obtain a high-quality printed image and is excellent in storage stability, particularly on a recording medium such as plain paper, recycled paper, or special paper for inkjet recording (for example, coated paper). Recording ink is provided.

[0002]

2. Description of the Related Art An ink jet recording method is a method of ejecting ink droplets from a fine nozzle head to record characters or figures on the surface of a recording medium such as paper. As the ink jet recording method, a method of converting an electric signal into a mechanical signal using an electrostrictive element and intermittently ejecting ink droplets stored in the nozzle head portion to record characters or symbols on the surface of the recording medium, or A portion of the nozzle head near the ejection portion rapidly heats a portion of the ink liquid to generate bubbles, and the volume expansion caused by the bubbles causes ink droplets to be ejected intermittently to form characters or symbols on the surface of the recording medium. Have been put to practical use.

As an ink jet recording ink, an aqueous pigment ink in which a pigment is dispersed in water has recently been provided. This is because the ink using the pigment has a characteristic of being superior in water resistance and light resistance to the ink using the water-soluble dye. In such an aqueous pigment ink, it is general practice to disperse the pigment in an aqueous dispersion medium using a dispersant such as a surfactant or a polymer dispersant. However, in these water-based pigment inks, the dispersant is simply adsorbed on the surface of the pigment particles, and a strong shearing force is applied when the ink liquid is ejected through the thin nozzle of the nozzle head. In some cases, the dispersant adsorbed on the surface of the particles may be released to deteriorate the dispersibility, resulting in unstable ejection.
In addition, the dispersibility tends to be unstable even when the above water-based pigment ink is stored for a long period of time.

As a means for solving such a drawback, there has been proposed a technique of covering the surface of pigment particles with a resin coating. For example, JP-A-08-218015 and JP-A-08-2
95837, Japanese Patent Application Laid-Open No. 09-3376, Japanese Patent Application Laid-Open No. 08-183920, Japanese Patent Application Laid-Open No. 10-46075.
JP-A-10-292143, JP-A-11
No. 80633, JP-A No. 11-349870, or JP-A No. 2000-7961 discloses an ink using a pigment coated with a resin having a film-forming property at room temperature by a phase inversion emulsification method. ing. Further, JP-A-9-31360, JP-A-9-217019, JP-A-9-316353, and JP-A-9-104.
No. 834, No. 9-151342, No. 10-140065, No. 11-152424.
JP-A-11-166145, JP-A-11-166145
No. 166145, JP-A No. 11-199983 or JP-A No. 11-209672 proposes an ink using a pigment coated with an anionic group-containing organic polymer compound by an acid precipitation method. . Furthermore, JP-A-9
-286939, JP2000-44852, JP2000-53897, JP2000-
No. 53898, JP 2000-53899 A,
Alternatively, JP-A-2000-53900 proposes an ink using a polymer emulsion obtained by impregnating polymer particles with a coloring material by a phase inversion emulsification method.

However, when the colorant obtained by the phase inversion emulsification method or the acid precipitation method as described above is used together with a penetrating agent (for example, glycol ethers or acetylene glycol-based surfactant), it is adsorbed on the surface of pigment particles. Since the unreacted resin component dissolves in the ink, or some of the resin adsorbed on the surface of the pigment particles is detached and dissolved in the ink, the amount of resin increases and so on. When printing on plain paper or recycled paper, it becomes difficult for the pigment, which is a coloring component, to remain on the surface of the paper fiber of the recording medium, it is difficult to obtain the print density, and the color developability deteriorates. Further, there are drawbacks such that bleeding easily occurs and the periphery of the nozzle is wet with ink and ejection becomes unstable easily. In particular, the image quality on plain paper or recycled paper is not sufficient. Further, when the ink is filled in the head and stored for a long period of time, the dispersion stability may be deteriorated, and it may be difficult to eject the ink from the nozzles of the head.

Japanese Unexamined Patent Publication (Kokai) No. 11-335602 proposes a recording ink using as a coloring material carbon black having a functional group generated by the decomposition of a radical generator made of a polymer containing an azo group chemically bonded to the surface. Further, JP-A-11-335603 proposes a recording ink using as a coloring material carbon black having a functional group generated by decomposition of a radical generator made of a peroxide polymer chemically bonded to the surface. ing.

[0007]

The object of the present invention is to provide excellent dispersibility in an aqueous system, high printing density and printing quality, fast drying property, excellent abrasion resistance and fixability, and An object of the present invention is to provide a water-based ink composition capable of obtaining a recorded material excellent in water resistance, light resistance, and chemical resistance. In particular, it is to provide an aqueous ink composition that can maintain dispersion stability even when a penetrant is used together.

[0008]

According to the present invention, the above-mentioned problems are represented by the general formula (I):

[0009]

[Chemical 9] [Wherein D is a moiety containing at least a hydrophobic segment, L ¹ and L ² are linker groups which can be the same or different, and R ¹ , R ² , R ³ and R ⁴ are respectively Independently, it is an alkyl group having 1 to 4 carbon atoms or a cyano group, and n is an integer of 1 or more] in the presence of a polymeric azo initiator containing a repeating unit and a vinyl polymerizable dispersant. And under conditions in which the polymeric azo initiator is not activated,
A microencapsulated colorant obtained by dispersing a water-insoluble colorant and subsequently activating the polymer azo initiator to polymerize the vinyl-based polymerizable dispersant in the obtained dispersion liquid is obtained. It can be solved by an aqueous dispersion characterized in that it contains.

The present invention also relates to an aqueous ink composition containing the above-mentioned aqueous dispersion, particularly an aqueous ink composition for ink jet recording.

[0011]

DETAILED DESCRIPTION OF THE INVENTION The aqueous dispersion of the present invention contains a microencapsulated colorant. In this microencapsulated colorant, the entire surface of the colorant particles is completely covered with the resin coating, and is completely included, that is, wrapped in the resin coating. The mechanism by which the microencapsulated colorant contained in the aqueous dispersion of the present invention is completely included in the resin coating has not been completely clarified, but the mechanism can be estimated as follows.

In preparing the aqueous dispersion according to the present invention, first, in the presence of a polymeric azo initiator containing a repeating unit represented by the general formula (I) and a vinyl-based polymerizable dispersant,
A water-insoluble coloring agent is dispersed in an aqueous dispersion medium. Since the polymeric azo initiator contains a hydrophobic portion and a hydrophilic portion in its repeating unit, it adheres to the colorant particle surface in the region of the hydrophobic portion of each repeating unit, In the region of the hydrophilic part of the repeating unit, it separates from the surface of the colorant particles and protrudes in a loop into the aqueous dispersion medium. Therefore, as many loops as the number of repeating units are formed on the surface of the colorant particles. Since the polymeric azo initiator is present in an amount that completely covers the surface of all colorant particles, the surface of each colorant particle is covered by the loop of the hydrophilic region. Similarly, the coexisting vinyl-based polymerizable dispersant also adheres to the surface of the colorant particles at the hydrophobic group portion and protrudes into the aqueous medium at the hydrophilic group portion. The dispersion step is performed under the condition that the polymer azo initiator is not activated, that is, under the condition that the azo group is not cleaved to generate a radical (for example,
(Under cooling).

Next, when the polymeric azo initiator is activated, the azo group contained in the polymeric azo initiator generates nitrogen (N ₂ ) and is cleaved to supply a radical. Since the vinyl-based polymerizable dispersant is dispersed in the dispersion medium system, radical polymerization by the vinyl-based polymerizable dispersant occurs from the cleavage portion, and the vinyl-based polymerizable dispersant is in a block form. , Bonded to the cleavage site. In this way, a polymer film is formed on the surface of the colorant particles and is firmly bonded to the surface of the colorant particles. Further, since the polymer coating contains a hydrophilic group which the vinyl-based polymerizable dispersant has, the colorant particle surface is completely covered by the polymer coating in which many hydrophilic groups are exposed, Shows good dispersibility.

Further, when a vinyl-based polymerizable dispersant having a cross-linking reactive group is used as the vinyl-based polymerizable dispersant and a crosslinking agent is present in the dispersion medium system, a polymer film is formed on the surface of the colorant particles. Is cross-linked, it is possible to form a polymer film that is more firmly bonded to the surface of the colorant particles.

As described above, it is presumed that the microencapsulated colorant contained in the aqueous dispersion of the present invention is completely contained in the resin film, but the present invention is based on the above reasoning. It is not limited.

The polymeric azo initiators, vinyl-based polymerizable dispersants, water-insoluble colorants, crosslinking agents, and other additives that can be used in the present invention will be described below in order.

Polymeric azo initiators that can be used in the present invention include, for example, compounds represented by the general formula (II):

[0018]

[Chemical 10] [In the formula, L ¹¹ and L ¹² can combine with the linking groups L ²¹ and L ²² in the general formula (III) described later to form the linker groups L ¹ and L ² in the general formula (I). And R ¹ , R ² , R ³ , and R ⁴ are each independently an alkyl group having 1 to 4 carbon atoms or a cyano group] and a general formula (III): L ²² -D-L ²¹ (III) [In the formula, L ²¹ and L ²² are bonded to the bonding groups L ¹¹ and L ¹² in the general formula (II) to form the linker group L ¹ in the general formula (I). And a group capable of forming L ² , and D is a moiety containing at least a hydrophobic segment].

In the present invention, in the above general formula (I), the portion D is a hydrophobic segment, and L ¹ and L ² are the same or different hydrophilic linker groups (eg ester bond). Alternatively, a polymeric azo initiator that is an amide bond) can be used. In this polymeric azo initiator, the part sandwiched between the hydrophilic linker groups L ¹ and L ² becomes the hydrophilic part.

In the present invention, in the general formula (I), the moiety D is represented by the general formula (11): -B ¹ -A ^1- (11) [wherein A ¹ is a hydrophilic segment. And B ¹ is a hydrophobic segment] can be used as the polymer azo initiator. The portion represented by the general formula (11) is, for example, the general formula (11a):

[0021]

[Chemical 11] [In the formula, h and j are integers of 1 or more, preferably 1 to 3
It is an integer of 0, more preferably an integer of 1 to 20, and still more preferably an integer of 4 to 20].

Furthermore, in the present invention, the general formula (I), the partial D has the general formula ^{(12): -A 2 -B 2} -A 3 - (12) [ wherein, A ² and A ³ is a hydrophilic segment which can be the same or different, and B ² is a hydrophobic segment], and a polymer azo initiator which is a portion represented by the formula can be used. The portion represented by the general formula (12) is
For example, general formula (12a):

[0023]

[Chemical 12] [In the formula, R ¹¹ and R ¹² are methyl groups, Y is an ethylene group, a, b, and c are integers of 1 or more, a is preferably 1 to 24, and b Is preferably 1
Is 20 and c is preferably 1 to 24]. [Alpha], [omega] -bis (polyoxyethylene) polydimethylsiloxane segment.

In the high molecular weight azo initiator represented by the general formula (I), the hydrophobic segment is not particularly limited as long as it has a property of adhering to the surface of the colorant particles, and examples thereof include a polysiloxane segment and a polyaryl segment. Segment, polyalkyl segment, and / or carbon number 3
It is preferable to contain the above polyalkylene oxide segment of alkylene.

As the polysiloxane segment,
For example, general formula (13):

[0026]

[Chemical 13] [In the formula, R ⁶ , R ⁷ , R ⁸ and R ⁹ are each independently an alkyl group having 1 to 4 carbon atoms (preferably a methyl group).
Or an aryl group having 6 to 10 carbon atoms (preferably a phenyl group), and d is 0 or an integer of 1 or more, preferably 1
And e is an integer of 1 or more, preferably an integer of 1 to 20, and more preferably an integer of 1 to 10], which is a polydialkylsiloxane segment (preferably a polydimethylsiloxane segment). ) Can be mentioned.

In the polymer azo initiator represented by the general formula (I), the hydrophilic segment is not particularly attached as long as it does not adhere to the surface of the colorant particles and protrudes into the dispersion medium to form a loop. For example, but not limited to, it is preferable to contain a polyethylene oxide segment.

Examples of the polyethylene oxide segment include those represented by the general formula (21):-(CH ₂ CH ₂ O) _t- (21) [wherein t is an integer of 1 or more, preferably an integer of 1 to 30]. ,
It is preferably an integer of 1 to 20, more preferably an integer of 4 to 20].

Examples of the high molecular weight azo initiators include:
General formula (Ia):

[0030]

[Chemical 14] [Wherein, R ¹ and R ³ are alkyl groups having 1 to 4 carbon atoms, R ² and R ⁴ are cyano groups, and R ⁶ , R ⁷ , R ⁸ and
And R ⁹ are each independently an alkyl group having 1 to 4 carbon atoms or an aryl group having 6 to 10 carbon atoms, and d is 0.
Or an integer of 1 or more, e, n, p, q, r, and s
Are each independently an integer of 1 or more]. In the general formula (Ia), R ¹ and R ³ are each preferably a methyl group, e is preferably an integer of 1 to 20, n is preferably an integer of 1 to 20, and p is Preferably 1-5
And q is an integer of 1 to 30,
r is preferably an integer from 1 to 5 and s is preferably 1
Is an integer of ~ 5.

Further, the general formula (Ib):

[0032]

[Chemical 15] [In the formula, R ¹ and R ³ are alkyl groups having 1 to 4 carbon atoms, R ² and R ⁴ are cyano groups, and R ¹¹ and R ¹² are
Each independently represents an alkyl group having 1 to 4 carbon atoms or an aryl group having 6 to 10 carbon atoms, a, b, c, f, g,
And n is an integer of 1 or more]. In the general formula (Ib), R ¹
And R ³ are each preferably a methyl group, and R 3
¹¹ and R ¹² are each preferably a methyl group,
a is preferably an integer of 1 to 24, b is preferably an integer of 1 to 20, c is preferably an integer of 1 to 24, f is preferably an integer of 1 to 5, and g is It is preferably an integer of 1 to 5, and n is preferably an integer of 1 to 20.

Further, the general formula (Ic):

[0034]

[Chemical 16] [In the formula, R ¹ and R ³ are alkyl groups having 1 to 4 carbon atoms, R ² and R ⁴ are cyano groups, and α, β, h, j,
And n are each independently an integer of 1 or more]. The general formula (I
In c), R ¹ and R ³ are each preferably a methyl group, α is preferably an integer of 1 to 5, and β is
Is preferably an integer of 1 to 5, and h is preferably 1 to
Is an integer of 30, j is preferably an integer of 1 to 30, and n is preferably an integer of 1 to 20.

The amount of the polymeric azo initiator added is not particularly limited as long as it covers the entire surface of the colorant particles, but is preferably 1 based on the total weight of the colorant.
-30% by weight, more preferably 3-10% by weight. When the amount of the polymeric azo initiator added is 1% by weight or more, the dispersion stability of the colorant can be improved. Moreover, by making it 30% by weight or less,
It is possible to suppress the generation of unadsorbed polymeric azo initiator on the pigment particles, and to prevent the generation of polymer particles having no core substance other than the encapsulated particles. Further, particularly when it is 3% by weight or more, the dispersion stability of the colorant can be further improved, and when it is 10% by weight or less, an increase in the particle diameter of the encapsulated particles can be suppressed.

The vinyl-based polymerizable dispersant that can be used in the present invention is dispersible in an aqueous dispersion medium,
It is not particularly limited as long as it has a vinyl group radically polymerizable by an azo initiator, and for example, a compound containing at least a vinyl polymerizable group, a hydrophobic group and a hydrophilic group, particularly a polymerizable interface. It is an activator.

Examples of the vinyl-based polymerizable group include:
Examples thereof include vinyl group, allyl group, acryloyl group, methacryloyl group, propenyl group, vinylidene group, and vinylene group. Moreover, as said hydrophilic group, a sulfone group, a sulfonic acid group, a carboxyl group, a carbonyl group, or these salts can be mentioned, for example. Furthermore, examples of the hydrophobic group include an alkyl group, an aryl group, and a group in which these are combined.

Specific examples of the polymerizable surfactant include Japanese Patent Publication No. 49-46291 and Japanese Patent Publication No. 1-241.
42, or an anionic allyl derivative as described in JP-A-62-104802, an anionic propenyl derivative as described in JP-A-62-221431, No. 62-34947 or Japanese Patent Application Laid-Open No. 55-11525, anionic acrylic acid derivatives, JP-B-46-
Anionic itaconic acid derivatives as described in JP-A-34898 or JP-A-51-30284,
JP-B-51-4157 or JP-A-51-3028
Anionic maleic acid derivative as described in JP-A No. 4-104802; Nonionic allyl derivative as described in JP-A-62-104802, JP-A-62-104802
Nonionic propenyl derivatives as described in JP 100502, Nonionic acrylic acid derivatives as described in JP-A-56-28208,
Nonionic itaconic acid derivatives as described in JP-B-59-12681, JP-A-59-7410
Examples thereof include nonionic maleic acid derivatives as described in JP-B No. 2; and cationic allyl derivatives as described in JP-B-4-65824.

The polymerizable surfactant used in the present invention is, for example, an acrylic acid-modified product of polyoxyethylene alkyl ether, an acrylic acid-modified product of polyoxyethylene alkylphenyl ether, or an acrylic acid of polyoxyethylene polystyryl phenyl ether. Acid modified product,
Examples thereof include polyoxyethylene-polyoxypropylene glycol monoacrylate.

Examples of the polymerizable surfactant preferably used in the present invention include those represented by the general formula (31):

[0041]

[Chemical 17] Wherein, R ²¹ and R ³¹ are each independently a hydrogen atom or a hydrocarbon group having 1 to 12 carbon atoms, Z ¹ is a carbon - carbon single bond or the formula -CH ₂ -O-CH ₂ - a group represented by, x is an integer of 2 to 20, X is a group represented by hydrogen or the formula -SO ₃ M ^1, M ¹ is an alkali metal, an ammonium salt, or an alkanolamine Or a compound represented by the formula (32):

[0042]

[Chemical 18] [Wherein, R ²² and R ³² are each independently a hydrogen atom or a hydrocarbon group having 1 to 12 carbon atoms, and Z ² is a carbon-carbon single bond or a formula —CH ₂ —O—CH ₂ - a group represented by, y is an integer from 2 to 20, Y is a group represented by hydrogen or the formula -SO ₃ M ^2, M ² is an alkali metal, an ammonium salt, or an alkanolamine Are preferred.

The polymerizable surfactant represented by the above formula (31) is disclosed in JP-A-5-320276 or JP-A-10-32076.
-316909. By appropriately adjusting the type of R ²¹ and the value of x in the formula (31), it is possible to correspond to the degree of hydrophilicity or hydrophobicity of the colorant surface. As the preferable polymerizable surfactant represented by the formula (31), specifically, the following formula (31)
The compounds represented by a) to (31d) may be mentioned.

[0044]

[Chemical 19]

[Chemical 20]

[Chemical 21]

[Chemical formula 22] A commercial item can also be used as said polymeric surfactant. For example, the Aqualon HS series (Aquaron HS-05, HS-10, H
S-20, HS-1025), Aqualon RN series (RN-10, RN-20, RN-30, RN-50,
RN-2025), New Frontier series (New Frontier N-177E, S-510), or Asahi Denka Kogyo Co., Ltd.'s ADEKA rear soap SE series, ADEKA rear soap NE series, etc. can be mentioned.

These polymerizable surfactants can be used alone or as a mixture of two or more kinds.

In the present invention, a hydrophilic monomer may be used as the vinyl-based polymerizable dispersant. As the hydrophilic monomer, any monomer that can be radically polymerized by an azo initiator and can be dispersed in an aqueous dispersion medium can be used.

The hydrophilic monomer has a hydrophilic group and a vinyl-based polymerizable group in its structure, and examples of the hydrophilic group include a sulfone group, a sulfonic acid group, a carboxyl group, a carbonyl group, or these groups. Examples of the salt, a hydroxyl group, a polyethylene oxide group, and the like, as the vinyl-based polymerizable group, for example, a vinyl group, an allyl group, an acryloyl group, a methacryloyl group, a propenyl group, a vinylidene group,
Or a vinylene group can be mentioned. Specifically, for example, methacrylic acid, acrylic acid, 2-hydroxyl methacrylate, ethyldiethylene glycol acrylate, polyethylene glycol monomethacrylate, methoxy polyethylene glycol methacrylate, phosphoric acid group-containing (meth) acrylate, N-vinyl-2-pyrrolidone, vinyl. Sodium sulfonate, 2-sulfoethyl methacrylate, 2-acrylamido-2-methylpropane sulfonic acid and the like can be mentioned.

These hydrophilic monomers can also be used alone or as a mixture of two or more kinds. Furthermore,
It is also possible to use one or more of the above-mentioned polymerizable surfactants in combination with one or more of the above-mentioned hydrophilic monomers.

The addition amount of the vinyl-based polymerizable dispersant is not particularly limited as long as it is an amount that can completely cover the entire surface of the colorant particles with the resin coating, but is based on the total weight of the colorant. The range is preferably 5 to 70% by weight, more preferably 10 to 50% by weight. When the amount of the vinyl-based polymerizable dispersant added is 5% by weight or more, the dispersion stability of the colorant can be improved. Also, 70
By controlling the content to be less than or equal to wt%, the generation of vinyl-based polymerizable dispersant that has not been adsorbed to the pigment particles is suppressed, and the generation of polymer particles or core-soluble polymer other than encapsulated particles or water-soluble polymer is prevented. can do. Also,
Particularly, when it is 10% by weight or more, the dispersion stability of the colorant can be further improved, and when it is 50% by weight or less, an increase in the particle size of the encapsulated particles can be suppressed.

In the present invention, a pigment or an oil-soluble dye can be used as the water-insoluble coloring agent.

Examples of oil-soluble dyes include disperse dyes,
A vat dye, an organic solvent-soluble dye, or the like can be used.

The pigment used in the present invention is not particularly limited, and either an inorganic pigment or an organic pigment can be used. As the inorganic pigment, for example, titanium oxide, iron oxide, furnace black, lamp black, acetylene black, carbon black such as channel black, and the like can be used. The organic pigments include azo pigments (including azo lakes, insoluble azo pigments, condensed azo pigments, chelate azo pigments, etc.), polycyclic pigments (eg, phthalocyanine pigments, perylene pigments, perinone pigments, anthraquinone pigments, quinacridone pigments). , Dioxane pigment, thioindigo pigment, isoindolinone pigment, or quinofuranone pigment), dye chelate (for example, basic dye type chelate or acid dye type chelate), nitro pigment, nitroso pigment, or aniline black You can

More specifically, as a pigment used for black ink, the following carbon black, for example, No. Mitsubishi Chemical No. 2300, No. 900, MCF88,
No. 33, No. 40, No. 45, No. 52, M
A7, MA8, MA100, or No2200B, etc .; Raven 5750, Raven 525 manufactured by Colombia.
0, Raven5000, Raven3500, Rav
en1255, Raven700, etc .; Regal 400R, Regal 330R, R manufactured by Cabot Corporation
egal 660R, Mogul L, Monarch
700, Monarch 800, Monarch
880, Monarch 900, Monarch 1
000, Monarch 1100, Monarch
1300, or Monarch 1400, etc .; or Color Black FW1, manufactured by Degussa,
Color Black FW2, Color Bla
ckFW2V, Color Black FW18, C
color Black FW200, Color Bl
ack S150, Color Black S16
0, Color Black S170, Printe
x35, Printex U, Printex V,
Printex 140U, Special Black
6, Special Black 5, Specia
l Black 4A or Special Blac
k 4 or the like can be used.

Examples of the pigment used for the yellow ink include C.I. I. Pigment Yellow
1, C.I. I. Pigment Yellow 2,
C. I. Pigment Yellow 3, C.I. I.
Pigment Yellow 12, C.I. I. Pigm
ent Yellow 13, C.I. I. Pigment
Yellow 14C, C.I. I. Pigment Y
ellow 16, C.I. I. Pigment Yell
ow 17, C.I. I. Pigment Yellow
73, C.I. I. Pigment Yellow 74,
C. I. Pigment Yellow 75, C.I.
I. Pigment Yellow 83, C.I. I. P
igment Yellow 93, C.I. I. Pigm
ent Yellow 95, C.I. I. Pigment
Yellow 97, C.I. I. Pigment Ye
low 98, C.I. I. Pigment Yellow
w110, C.I. I. Pigment Yellow 1
14, C.I. I. Pigment Yellow 12
8, C.I. I. Pigment Yellow 129,
C. I. Pigment Yellow 151, or C.I. I. Pigment Yellow 154 and the like.

The pigment used for magenta ink is, for example, C.I. I. Pigment Red
5, C.I. I. Pigment Red 7, C.I. I. P
igment Red 12, C.I. I. Pigment
Red 48 (Ca), C.I. I. Pigment R
ed 48 (Mn), C.I. I. Pigment Red
57 (Ca), C.I. I. Pigment Red 5
7: 1, C.I. I. Pigment Red 112,
C. I. Pigment Red 122, C.I. I. P
igment Red 123, C.I. I. Pigmen
t Red 168, C.I. I. Pigment Red
184, or C.I. I. PigmentRed 202
Etc. can be mentioned.

Examples of pigments used for cyan ink include C.I. I. PigmentBlue 1,
C. I. Pigment Blue 2, C.I. I. Pi
gment Blue 3, C.I. I. Pigment
Blue 15: 3, C.I. I. Pigment Blu
e 15:34, C.I. I. Pigment Blue1
6, C.I. I. Pigment Blue 22, C.I.
I. Pigment Blue 60, C.I. I. Vat
Blue 4, or C.I. I. Vat Blue 60 etc. can be mentioned. However, it is not limited to these.

In the present invention, as the vinyl-based polymerizable dispersant, a vinyl-based polymerizable dispersant having a crosslinking reactive group in addition to the vinyl group participating in the radical polymerization is used, and at the same time, the crosslinking agent is used. It can be used to make the polymer coating on the surface of the colorant particles a crosslinked coating.

Examples of the cross-linking reactive group include glycidyl group, isocyanate group, hydroxyl group, or unsaturated hydrocarbon group (for example, vinyl group, allyl group, acryloyl group, methacryloyl group, propenyl group, vinylidene group,
And vinylene group).

The cross-linking agent is not particularly limited as long as it has a high copolymerization reactivity with the vinyl-based polymerizable dispersant, but is not limited to vinyl group, allyl group, acryloyl group, methacryloyl group, propenyl. An unsaturated hydrocarbon group selected from a vinyl group, a vinylidene group, and a vinylene group.
It is preferable to use a compound having two or more. Specific examples are as follows.

Ethylene glycol diacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, tetraethylene glycol diacrylate, polyethylene glycol diacrylate, allyl acrylate, bis (acryloxyethyl) hydroxyethyl isocyanurate, bis (acryloxy neopentyl glycol) ) Adipate, 1,3-butylene glycol diacrylate, 1,6-hexanediol diacrylate, neopentyl glycol diacrylate, propylene glycol diacrylate, polypropylene glycol diacrylate, 2-hydroxy-1,
3-Diacryloxypropane, 2,2-bis [4- (acryloxy) phenyl] propane, 2,2-bis [4-
(Acryloxyethoxy) phenyl] propane, 2,2
-Bis [4- (acryloxyethoxy / diethoxy) phenyl] propane, 2,2-bis [4- (acryloxyethoxy / polyethoxy) phenyl] propane, hydroxybivalic acid neopentyl glycol diacrylate, 1,4-butane Diol diacrylate, dicyclopentanyl diacrylate, dipentaerythritol hexaacrylate, dipentaerythritol monohydroxypentaacrylate, ditrimethylolpropane tetraacrylate, pentaerythritol triacrylate, tetrabromopisphenol A diacrylate,
Triglycerol diacrylate, trimethylolpropane triacrylate, tris (acryloxyethyl)
Isocyanurate, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, propylene glycol dimethacrylate, polypropylene glycol dimethacrylate, 1,
3-butylene glycol dimethacrylate, 1,4-butanediol dimethacrylate, 1,6-hexanediol dimethacrylate, neopentyl glycol dimethacrylate, 2-hydroxy-1,3-dimethacryloxypropane, 2,2-bis [ 4- (methacryloxy) phenyl] propane, 2,2-bis [4- (methacryloxyethoxy) phenyl] propane, 2,2-bis [4-
(Methacryloxyethoxydiethoxy) phenyl] propane, 2,2-bis [4- (methacryloxyethoxypolyethoxy) phenyl] propane, tetrabromobisphenol A dimethacrylate, dicyclopentanyl dimethacrylate, dipentaerythritol hexamethacrylate, Glycerol dimethacrylate, hydroxybivalate neopentyl glycol dimethacrylate, dipentaerythritol monohydroxypentamethacrylate, ditrimethylolpropane tetramethacrylate, pentaerythritol trimethacrylate, pentaerythritol tetramethacrylate, triglycerol dimethacrylate, trimethylolpropane trimethacrylate, Tris (methacryloxyethyl) isocyanurate, allyl Methacrylate, divinylbenzene, diallyl phthalate, can be mentioned diallyl terephthalate, diallyl isophthalate, or diethylene glycol bis allyl carbonate.

The aqueous dispersion of the present invention comprises (1) in the presence of the above-mentioned polymer azo initiator and the above vinyl-based polymerizable dispersant,
A step of dispersing a water-insoluble colorant under conditions in which the polymer azo initiator is not activated (hereinafter referred to as a dispersion step), and subsequently (2) in the obtained dispersion liquid,
It can be prepared by a step of activating the polymeric azo initiator to polymerize the polymerizable dispersant (hereinafter referred to as a polymerization step).

In the dispersing step, a colorant, a high molecular weight azo initiator, a vinyl-based polymerizable dispersant, and a water-soluble organic solvent and / or water are cooled, if necessary, with a ball mill, a sand grinder or the like. By wet pulverization or ultrasonic treatment. Alternatively, the colorant, the high molecular weight azo initiator, and the water-soluble organic solvent or / and water are wet-ground by a ball mill, a sand grinder, or the like while being cooled, if necessary, or subjected to ultrasonic treatment, and further. A vinyl-based polymerizable dispersant can be added and the same treatment can be performed. If necessary, a crosslinking agent can be further added. As a cooling method, for example, a method of circulating cooling water in a ball mill, a sand grinder or the like using a circulator can be used. The cooling temperature varies depending on the polymer azo initiator used, but is preferably 20 ° C. or lower, more preferably 10 ° C. or lower.

Then, the above mixture (dispersion liquid) is placed in a reaction vessel equipped with an ultrasonic generator, a stirrer, a temperature controller, a reflux condenser and a dropping funnel, and the water-soluble organic solvent and / or water is added to complete the reaction. After adding so that the solid content concentration afterwards becomes 10 to 30% by weight and stirring well, heating to the decomposition temperature of the polymer azo initiator to activate the polymer azo initiator, radical polymerization is performed. And, if necessary, a crosslinking reaction with a crosslinking agent. The heating temperature varies depending on the polymer azo initiator used, but is preferably 60 ° C to 80 ° C.

From the aqueous dispersion thus obtained, an ink composition (for example, an ink composition for ink jet recording) can be prepared by a conventional method. In addition, when the compounding components of the ink composition are added in the dispersion step and / or the polymerization step, the ink composition (for example, the ink composition for inkjet recording) is directly obtained from the dispersion step and the polymerization step. It can be prepared.

With respect to the oil-soluble dye, the microencapsulated dye contained in the resin film or the microencapsulated dye further contained in the crosslinked resin film can be obtained by the same method as described above.

In the present invention, the amount of the colorant added is preferably 0.5 to 30% by weight, based on the weight of the ink composition (for example, the ink composition for ink jet recording).
It is more preferably 1 to 15% by weight. By setting the addition amount of the colorant to 1% by weight or more, a sufficient print density can be secured, and by setting it to 15% by weight or less,
It is possible to prevent the viscosity of the ink composition from increasing and the ejection stability from deteriorating. The particle size of the colorant is preferably 2
It is at most 00 nm, more preferably at most 150 nm.

In a preferred embodiment of the ink composition containing the macroencapsulated colorant according to the present invention (particularly, the ink composition for ink jet recording), (1) the microencapsulated colorant according to the present invention, and (2) acetylene. Glycol-based surfactant and / or acetylene alcohol-based surfactant, (3) diethylene glycol monobutyl ether, triethylene glycol monobutyl ether, propylene glycol monobutyl ether, dipropylene glycol monobutyl ether, and / or 1, 4-10 carbon atoms One or more compounds (penetrating agents) selected from the group consisting of 2-alkylene glycols, and (4)
Including at least water. Such an ink composition (particularly,
The ink composition for inkjet recording) is excellent in dispersion stability and ejection stability, and further, stable printing is possible over a long period of time without nozzle clogging. In addition, in recording media such as plain paper, recycled paper and coated paper, it is possible to obtain a high-quality image that has good dryability after printing, has no bleeding, has a high print density, and has excellent color development. .

Generally, when a pigment is dispersed, a dispersant such as a surfactant or a polymer dispersant is used, but since these dispersants are simply adsorbed on the pigment particle surface, they are usually used. The dispersant tends to be detached from the surface of the pigment particle due to some environmental factor. On the other hand, in the present invention, as described above, the surface of the pigment particles is completely covered with the polymer coating or the crosslinked polymer coating, and the polymer coating or the crosslinked polymer coating surrounding the pigment particle surface is very strong. It is considered that since the pigment particles adhere to the surface of the pigment particles, they are difficult to be detached from the surface of the pigment particles.

More specifically, the above-mentioned acetylene glycol surfactant and / or acetylene alcohol surfactant is prepared by using a pigment dispersion liquid in which a pigment is dispersed using a dispersant such as a surfactant or a polymer dispersant. In addition, an ink with improved permeability with a penetrant such as diethylene glycol monobutyl ether, triethylene glycol monobutyl ether, propylene glycol monobutyl ether, dipropylene glycol monobutyl ether, or 1,2-alkylene glycol is ejected through a thin nozzle. Due to the strong shearing force applied at the time of dispersion, the dispersant is easily detached from the surface of the pigment, resulting in deterioration of dispersibility, and ejection tends to be unstable.

On the other hand, in the ink composition using the above-mentioned microencapsulated colorant according to the present invention, such a phenomenon is not observed at all, and stable ejection is performed. Further, since the polymer coating or the cross-linked polymer coating contains the colorant, good solvent resistance can be obtained, and therefore, the above-mentioned penetrant promotes desorption from the colorant and swelling of the polymer occurs. It becomes difficult, and excellent dispersion stability can be maintained for a long period of time.

Further, in an ink composition using a pigment dispersion liquid in which a pigment is dispersed using a dispersant such as a surfactant or a polymer dispersant, and having improved penetrability, generally, the pigment surface is formed on the pigment surface from the beginning of dispersion. The content of the pigment is often limited because the viscosity of the ink composition tends to increase due to the dispersant that is not adsorbed and is dissolved in the liquid or the dispersant that is subsequently released from the pigment. Therefore, particularly on plain paper or recycled paper, it is often impossible to obtain a sufficient print density and good color developability cannot be obtained. On the other hand, in the ink composition using the microencapsulated colorant according to the present invention, since the polymer coating or the crosslinked polymer coating contains the colorant as described above, it is difficult to separate from the colorant. Therefore, since there is no increase in the viscosity of the ink composition, it is easy to lower the viscosity of the ink composition, and it has the advantage that it can contain a larger amount of colorant, and sufficient printing on plain paper or recycled paper is possible. The concentration can be obtained.

In a preferred embodiment of the ink composition (particularly, the ink composition for ink jet recording) containing the microencapsulated colorant according to the present invention, the acetylene glycol surfactant and / or the acetylene alcohol surfactant is used. The addition amount is preferably 0.01 to 10% by weight, more preferably 0.1 to 5% by weight, based on the total weight of the ink composition. Examples of acetylene glycol-based surfactants include Surfynol series manufactured by Air Products (USA).

In a preferred embodiment of the ink composition (particularly the ink composition for ink jet recording) containing the microencapsulated colorant according to the present invention, the amount of diethylene glycol monobutyl ether or triethylene glycol monobutyl ether as the penetrant added is It is preferably 10% by weight or less, more preferably 0.5 to 5% by weight, based on the total weight of the ink composition. Addition of diethylene glycol monobutyl ether and triethylene glycol monobutyl ether has a remarkable effect on improving the permeability. Further, the addition of diethylene glycol monobutyl ether and / or triethylene glycol monobutyl ether is useful for improving the solubility of the acetylene glycol-based surfactant and improving the print quality.

In a preferred embodiment of the ink composition (in particular, the ink composition for ink jet recording) containing the microencapsulated colorant according to the present invention, 1,2-alkylene glycol having 4 to 10 carbon atoms is used as the penetrant. The amount added is preferably 15 based on the total weight of the ink composition.
It is less than or equal to weight%. Sufficient permeability cannot be obtained with 1,2-alkylene glycols having 3 or less carbon atoms and the carbon number is 1
When it exceeds 5, it becomes difficult to dissolve in water, which is not preferable.
If the addition amount exceeds 15% by weight, the viscosity tends to increase, which is not suitable. Specific examples of 1,2-alkylene glycol include 1,2-pentanediol or 1,2-pentanediol.
It is preferred to use -hexanediol, which can be used alone or both. 1,2-Pentanediol is preferably added in the range of 3 to 15% by weight. If it is less than 3% by weight, good permeability cannot be obtained. 1,2-hexanediol is 0.5 to 10% by weight
It is preferable to add in the range of. If it is less than 0.5% by weight, good permeability cannot be obtained.

The solvent of the ink composition according to the present invention (particularly, the ink composition for ink jet recording) contains water and a water-soluble organic solvent as a basic solvent, and, if necessary, contains any other component. You can

The preferred ink composition of the present invention (particularly the ink composition for ink jet recording) may contain a water-soluble organic solvent. Specific examples thereof include alkyl alcohols having 1 to 4 carbon atoms such as ethanol, methanol, butanol, propanol, or isopropanol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, ethylene glycol monomethyl ether acetate, Diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol mono-n-propyl ether, ethylene glycol mono-iso-propyl ether, diethylene glycol mono-iso-propyl ether, ethylene glycol mono-n-butyl ether, diethylene glycol mono-n-butyl ether, tri Ethylene glycol mono-n-butyl ether, ethyl Glycol monobutyl -t- butyl ether, diethylene glycol monobutyl -t- butyl ether, 1-methyl-1-methoxybutanol, propylene glycol monomethyl ether,
Propylene glycol monoethyl ether, propylene glycol mono-t-butyl ether, propylene glycol mono-n-propyl ether, propylene glycol mono-iso-propyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol mono- n
-Propyl ether, dipropylene glycol mono-i
So-propyl ether, propylene glycol mono-
Examples thereof include glycol ethers such as n-butyl ether or dipropylene glycol mono-n-butyl ether, or formamide, acetamide, dimethyl sulfoxide, sorbit, sorbitan, acetin, diacetin, triacetin, sulfolane and the like.

Further, the preferable ink composition of the present invention (particularly the ink composition for ink jet recording) can contain a water-soluble organic solvent having a boiling point of 180 ° C. or higher among the above water-soluble organic solvents. When a water-soluble organic solvent having a boiling point of 180 ° C. or higher is used, water retention and wettability can be imparted to the ink composition. As a result, it is possible to provide an ink composition which maintains fluidity and redispersibility for a long time even when left in an open state (a state in which it is exposed to air at room temperature). Further, the nozzles are less likely to be clogged during printing or when restarted after printing is interrupted, and high ejection stability can be obtained.

Specific examples of the water-soluble organic solvent having a boiling point of 180 ° C. or higher include ethylene glycol, propylene glycol, diethylene glycol, pentamethylene glycol, trimethylene glycol, 2-butene-1,4-diol, 2-ethyl-1. , 3-hexanediol, 2-
Methyl-2,4-pentanediol, 1-methyl-2-
Pyrrolidone, 1,3-dimethyl-2-imidazolidinone, 2-pyrrolidone, glycerin, tripropylene glycol monomethyl ether, dipropylene glycol monoethyl glycol, dipropylene glycol monoethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol, Triethylene glycol monomethyl ether, tetraethylene glycol, triethylene glycol, diethylene glycol monobutyl ether, diethylene glycol monoethyl ether,
Diethylene glycol monomethyl ether, tripropylene glycol, polyethylene glycol having a molecular weight of 2000 or less, 1,3-propylene glycol, isopropylene glycol, isobutylene glycol, 1,4-butanediol, 1,3-butanediol, 1,5-pentanediol, 1,6-hexanediol, glycerin, mesoerythritol and pentaerythritol can be mentioned. An organic solvent having a boiling point of 200 ° C. or higher is preferable. These can be used alone or as a mixture of two or more kinds.

The content of these water-soluble organic solvents is preferably about 10 to 50% by weight, more preferably 10 to 30% by weight, based on the total weight of the ink composition.

According to a preferred embodiment of the ink composition of the present invention (in particular, the ink composition for ink jet recording), a sugar, a tertiary amine, or an alkali hydroxide can be further contained. Addition of sugars and tertiary amines improves wettability. Also, when alkali hydroxide and tertiary amine are added,
The dispersion stability of the colorant in the ink composition is improved.

Specific examples of the tertiary amine include trimethylamine, triethylamine, triethanolamine, diethanolamine, diethylethanolamine, triisopropenolamine and butyldiethanolamine. These can be used alone or as a mixture of two or more kinds. The amount of these tertiary amines added is preferably 0.1% based on the total weight of the ink composition.
1 to 10% by weight, more preferably 0.5 to 5% by weight
Is.

The alkali hydroxide is, for example, potassium hydroxide, sodium hydroxide or lithium hydroxide, and the addition amount thereof is preferably 0.1% with respect to the total weight of the ink composition.
It is about 01 to 5% by weight, more preferably 0.05 to 3% by weight.

Further, the ink composition of the present invention (particularly the ink composition for ink jet recording) may further contain a surfactant. The surfactant that can be used is preferably a surfactant having good compatibility with the ink composition of the present invention (particularly, the ink composition for inkjet recording), and has high permeability among the surfactants. It should be stable. Specific examples of the surfactant include sodium dodecylbenzenesulfonate as the anionic surfactant, sodium laurate, ammonium salts of polyoxyethylene alkyl ether sulfate, and the like, and specific examples of the nonionic surfactant. Polyoxyethylene nonyl phenyl ether, polyoxyethylene octyl phenyl ether, polyoxyethylene dodecyl phenyl ether, polyoxyethylene alkyl allyl ether, polyoxyethylene oleyl ether,
Ether system such as polyoxyethylene lauryl ether, polyoxyethylene alkyl ether, polyoxyalkylene alkyl ether, polyoxyethylene oleic acid, polyoxyethylene oleic acid ester, polyoxyethylene distearic acid ester, sorbitan laurate, sorbitan monostearate , Sorbitan monooleate, sorbitan sesquioleate, polyoxyethylene monooleate, polyoxyethylene stearate, and other ester-based compounds.

In addition, a pH adjusting agent, a dissolution aid, an antioxidant, a fungicide, a preservative, a corrosion inhibitor, and / or a metal salt may be added to the ink composition, if necessary, to improve storage stability. It is also possible to add an additive such as a trapping agent.

<Examples> The present invention will be specifically described below with reference to examples, but these do not limit the scope of the present invention.

<Preparation Example of Polymer Azo Initiator> (1) Preparation of Polymer Azo Initiator 1 The polymer azo initiator used in the present invention is described in JP-A-2000-5.
It was obtained by the method described in Japanese Patent No. 3716. Specifically, as described in Example 1 of the above publication, 4,4'-
Azobis (4-cyanopentanoic acid), α, ω-bis (polyoxyethylene) polydimethylsiloxane (number average molecular weight 1400) and 4-dimethylaminopyridine were dissolved in acetonitrile, dicyclohexylcarbodiimide was added, and the mixture was stirred at room temperature. After reaction, the precipitated crystals are removed, the filtrate is concentrated to dryness, and a high molecular weight azo initiator having both a polyorganosiloxane part and a polyoxyalkylene part in one molecule (hereinafter, high molecular weight azo initiator 1).

(2) Preparation of polymeric azo initiator 2 4,4'-azobis (4-cyanopentanoic acid) and the following formula (11b):

[0088]

[Chemical formula 23] The polyethylene glycol / polypropylene glycol block copolymer represented by and 4-dimethylaminopyridine are dissolved in acetonitrile, dicyclohexylcarbodiimide is added, and the mixture is reacted at room temperature to remove precipitated crystals, and the filtrate is concentrated and dried. After solidification, a polymer azo initiator having both a polyethylene glycol portion and a polypropylene glycol portion in one molecule (hereinafter, referred to as polymer azo initiator 2) was obtained.

<Preparation Example of Aqueous Dispersion of Microencapsulated Colorant> (1) Preparation of Microencapsulated Colorant MC1 100 g of carbon black (Raven C: Colombian Carbon Co., Ltd.) and 30 g of polymeric azo initiator 1 And ion-exchanged water 500g Eiger Motor Mill M25
Type 0 (made by Eiger Japan Co., Ltd.), and the mixture obtained by dispersing for 1 hour while cooling with cooling water under the conditions of a bead filling rate of 70% and a rotation speed of 5000 rpm, an ultrasonic generator, a stirrer, and temperature adjustment. Into a reaction vessel equipped with a vessel, a reflux condenser, and a dropping funnel, further, 15 g of the vinyl-based polymerizable dispersant (SE-10N: manufactured by Asahi Denka) of the formula (31A) and 2-sulfo as a hydrophilic monomer. After adding 15 g of ethyl methacrylate and 300 g of ion-exchanged water and stirring well, while stirring at 70 ° C. and irradiating with ultrasonic waves, 2
Polymerized for hours. The thus-obtained carbon black microencapsulated colorant aqueous dispersion (hereinafter referred to as microencapsulated colorant MC1) was measured by a laser Doppler particle size distribution analyzer Microtrac (UPA150: manufactured by Leeds & Northrop Co.). The average particle size was 120 nm.

(2) Preparation of Microencapsulated Colorant MC2 100 g of carbon black (Raven C: Colombian Carbon Co., Ltd.), 30 g of the polymeric azo initiator 2 and 500 g of ion-exchanged water were added to an Eiger Motor Mill M25.
Type 0 (made by Eiger Japan Co., Ltd.), and the mixture obtained by dispersing for 1 hour while cooling with cooling water under the conditions of a bead filling rate of 70% and a rotation speed of 5000 rpm, an ultrasonic generator, a stirrer, and temperature adjustment. Into a reaction vessel equipped with a vessel, a reflux condenser, and a dropping funnel, 15 g of the vinyl-based polymerizable dispersant (SE-10N: manufactured by Asahi Denka) of the formula (31A) and vinyl sulfonic acid as a hydrophilic monomer. Sodium 1
After adding 0 g, 5 g of diethylene glycol dimethacrylate as a cross-linking agent and 300 g of ion-exchanged water and stirring well, while stirring and irradiating ultrasonic waves at 70 ° C.,
Polymerized for 2 hours. The thus-obtained carbon black microencapsulated colorant aqueous dispersion (hereinafter referred to as microencapsulated colorant MC2) was measured with a laser Doppler particle size distribution analyzer Microtrac (UPA150: manufactured by Leeds & Northrop Co.). The average particle size was 130 nm.

(3) Preparation of Microencapsulated Colorant MC3 100 g of carbon black (Raven C: manufactured by Columbian Carbon Co., Ltd.), 30 g of the polymeric azo initiator 1 and 500 g of ion-exchanged water were mixed with Eiger Motor Mill M25.
Type 0 (made by Eiger Japan Co., Ltd.), and the mixture obtained by dispersing for 1 hour while cooling with cooling water under the conditions of a bead filling rate of 70% and a rotation speed of 5000 rpm, an ultrasonic generator, a stirrer, and temperature adjustment. Into a reaction vessel equipped with a vessel, a reflux condenser, and a dropping funnel, further, 15 g of the vinyl-based polymerizable dispersant (SE-10N: manufactured by Asahi Denka) of the formula (31A) and 2-acrylamide as a hydrophilic monomer. After adding 5 g of 2-methylpropanesulfonic acid, 4.2 g of methacrylic acid, 6.3 g of glycidyl methacrylate as a cross-linking agent and 300 g of ion-exchanged water and stirring well, while stirring at 70 ° C. and irradiating ultrasonic waves, Polymerized for 3 hours. The thus obtained aqueous dispersion of carbon black microencapsulated colorant (hereinafter referred to as microencapsulated colorant M
C3) was measured with a laser Doppler type particle size distribution analyzer Microtrac (UPA150: manufactured by Leeds & Northrop Co.), and as a result, the average particle diameter was 110 nm.

(4) Preparation of Microencapsulated Colorant MC4 C.I. I. Pigment Blue 15 (Fastgen Blue TGR: manufactured by Dainippon Ink and Chemicals, Inc.) 100g
And 30 g of polymer azo initiator 1 and 500 g of deionized water
And were put into an Eiger motor mill type M250 (manufactured by Eiger Japan), and the bead filling rate was 70% and the rotation speed was 500.
The mixture obtained by dispersing for 1 hour while cooling with cooling water under the condition of 0 rpm was placed in a reaction vessel equipped with an ultrasonic generator, a stirrer, a temperature controller, a reflux condenser, and a dropping funnel, and further vinyl. 15 g of a polymerizable dispersant (New Frontier N-177E: manufactured by Dai-ichi Kogyo Kabushiki Kaisha) and 2-sulfoethyl methacrylate 15 as a hydrophilic monomer
g and ion-exchanged water 300 g and stirred well,
Polymerization was carried out for 2 hours while stirring and irradiating ultrasonic waves at 70 ° C. Thus obtained C. I. Pigment Blue 1
The micro-encapsulated colorant aqueous dispersion of 5 (hereinafter referred to as micro-encapsulated colorant MC4) was used as a laser Doppler type particle size distribution analyzer Microtrac (UPA15
0: manufactured by Leeds & Northrop Co.), and as a result, the average particle diameter was 120 nm.

(5) Preparation of Microencapsulated Colorant MC5 C.I. I. Pigment Red 122 (Fastgen Super Magenta RTS: manufactured by Dainippon Ink and Chemicals, Inc.), 30 g of high molecular weight azo initiator 2 and 500 g of ion-exchanged water were added to Eiger Motor Mill M250.
Put into a mold (manufactured by Eiger Japan) and fill the beads with a rate of 7
The mixture obtained by dispersing for 1 hour while cooling with cooling water under the condition of 0% and a rotation speed of 5000 rpm was treated with an ultrasonic generator,
It was placed in a reaction vessel equipped with a stirrer, a temperature controller, a reflux condenser, and a dropping funnel, and further, as a hydrophilic monomer, 15 g of a vinyl-based polymerizable dispersant (Aqualon HS-10: manufactured by Dai-ichi Kogyo Kabushiki Kaisha). Sodium vinyl sulfonate 10
g, 5 g of 1,6-hexanediol diacrylate as a cross-linking agent, and 300 g of ion-exchanged water were added and stirred well, then at 70 ° C. with stirring and irradiation with ultrasonic waves, 2
Polymerized for hours. Thus obtained C. I. Pigment
The average particle diameter of the red 122 microcapsulated colorant aqueous dispersion (hereinafter referred to as the microcapsule colorant MC5) was measured with a laser Doppler particle size distribution analyzer Microtrac (UPA150: manufactured by Leeds & Northrop Co.). Was 140 nm.

(6) Preparation of Microencapsulated Colorant MC6 C.I. I. Pigment Yellow 17 (Shimla First Yellow 8GF: Dainippon Ink and Chemicals, Inc.)
100 g, 30 g of polymer azo initiator 1 and 500 g of ion-exchanged water were put into an Eiger motor mill M250 type (made by Eiger Japan Co.), and with cooling water under the conditions of a bead packing rate of 70% and a rotation speed of 5000 rpm. The mixture obtained by dispersing for 1 hour while cooling was placed in a reaction vessel equipped with an ultrasonic generator, a stirrer, a temperature controller, a reflux condenser, and a dropping funnel, and further, a vinyl-based polymerizable dispersant (31A).
SE-10N (manufactured by Asahi Denka) of the formula, 5 g of N-vinyl-2-pyrrolidone as a hydrophilic monomer, 4.2 g of methacrylic acid, 6.3 g of glycidyl methacrylate as a cross-linking agent and 300 g of deionized water were added. After stirring well, polymerization was carried out for 3 hours while stirring and irradiating ultrasonic waves at 70 ° C. Thus obtained C. I. Pigment Yellow 17 microencapsulated colorant aqueous dispersion (hereinafter referred to as microencapsulated colorant MC6) was measured by a laser Doppler particle size distribution analyzer Microtrac (UPA150: manufactured by Leeds & Northrop Co., Ltd.), The average particle size was 110 nm.

<Preparation Example of Ink Composition> An ink composition for ink jet recording according to the present invention (Examples 1 to 6) and a comparative ink jet using the above-mentioned aqueous dispersion of microencapsulated colorant according to the present invention. Recording ink compositions (Comparative Examples 1 and 2) were prepared as follows, and various physical properties were compared.

Example 1 Microencapsulated Colorant M
8 g of C1 (as solid content), 12 g of glycerin, 1,
2-Hexanediol 5 g, acetylene glycol surfactant (Surfynol 104) 0.3 g, and acetylene glycol surfactant Surfynol 485)
Ion-exchanged water was added to 0.7 g of the mixed solution to make the total amount of the mixed solution 100 g. Further, triethanolamine was added to adjust the pH of the mixed solution to 7.5. After stirring this mixed solution for 2 hours, it was filtered through a stainless steel filter having a pore size of about 5 μm to prepare an ink composition for inkjet recording according to the present invention.

<Examples 2 to 6> Based on the compositions shown in Table 1 below, the ink compositions for ink jet recording of Examples 2 to 6 were prepared using the procedure described in Example 1 above. .

Comparative Example 1 100 g of carbon black (Raven C: Columbian Carbon Co., Ltd.), 150 g of a dispersant (John Cryl J-62: Johnson Polymer Co., Ltd.), 6 g of sodium hydroxide, and 250 g of water.
And mix with a zirconia bead in a ball mill.
Dispersed for 0 hours. The obtained dispersion liquid was filtered through a stainless steel filter having a pore size of about 5 μm and diluted with water to a pigment concentration of 20 wt% to prepare a carbon black dispersion liquid. 30 g of the obtained pigment dispersion liquid, 10 g of glycerin
And 2-pyrrolidone (5 g) were mixed with ethanol (4 g), and ion-exchanged water was added so that the total amount became 100 g. This mixed solution was stirred for 2 hours and filtered through a stainless steel filter having a pore size of about 5 μm to prepare a comparative inkjet recording ink composition.

Comparative Example 2 To 30 g of the pigment dispersion prepared in Comparative Example 1, 10 g of glycerin and 7 g of triethylene glycol monobutyl ether were added and mixed, and then triethanolamine was further added to adjust the pH of the ink to 7. 5
Adjusted to. The mixed solution was further stirred for 2 hours and then filtered through a stainless steel filter having a pore size of about 5 μm to prepare a comparative inkjet recording ink composition.

[0100]

[Table 1] <Physical property evaluation> The above-mentioned Examples 1 to 6 and Comparative Examples 1 to 1
The ink compositions for ink jet recording prepared in Comparative Example 2 and the recorded products printed with these ink compositions were evaluated by the methods described below.

(1) Dispersion Stability The ink compositions for ink jet recording prepared in Examples 1 to 6 and Comparative Examples 1 and 2 were mixed with a rolling ball viscometer (automatic micro viscometer AMVn: Paar).
Physica) at 30 ° C. at 30 ° C.
Measure the viscosity of each tilt angle of degrees, 50 degrees, and 70 degrees,
The horizontal axis is sin θ, and the vertical axis is viscosity.
The inθ-viscosity curve was obtained and the slope of the sinθ-viscosity curve was determined. The obtained results were evaluated according to the following criteria. The results are shown in Table 2. A: The absolute value of the slope of the sin θ-viscosity curve is 0 to 0.02.
Below (excellent in dispersion stability) B: Absolute value of slope of sin θ-viscosity curve exceeds 0.02 and 0.05 or less (good dispersion stability) C: Absolute value of slope of sin θ-viscosity curve is Over 0.05

(2) Storage stability The ink compositions for ink jet recording prepared in the above Examples 1 to 6 and Comparative Examples 1 and 2 were placed in glass sample bottles and sealed tightly. 2 at 60 ° C
After being left for a week, the viscosity of the ink before and after standing was examined. The viscosity was measured at 20 ° C. using a rolling ball viscometer (automatic micro-viscosity meter AMVn: manufactured by Paar Physica). Specifically, the viscosities before and after standing at an inclination angle of 30 degrees were compared. The obtained results were evaluated according to the following criteria. The results are shown in Table 2. A: The amount of change in viscosity is less than ± 0.1 mPa · s. (Excellent storage stability.) B: The amount of change in viscosity is ± 0.1 or more and less than 0.3 mPa · s. (Good storage stability.) C: Viscosity change amount is ± 0.3 or more.

(3) Printing Density Using the ink composition for ink jet recording prepared in Examples 1 to 6 and Comparative Examples 1 and 2 and Ink Jet Printer (EM-900C: manufactured by Seiko Epson Corporation). In plain paper clean mode, use plain paper (Xe
Rox P: manufactured by Xerox) was subjected to solid printing, and the printed portion was measured for printing density (OD value) with a Macbeth densitometer (SPM-50: Gretag Macbeth) and evaluated according to the following criteria. The results are shown in Table 2. A: Black ink 1.4 or more color ink 1.2 or more B: Black ink 1.3 or more and less than 1.4 Color ink 1.1 or more and less than 1.2 C: Black ink Color ink less than 1.3 Color ink less than 1.1

(4) Print Quality Using the ink compositions for ink jet recording prepared in Examples 1 to 6 and Comparative Examples 1 and 2 and Ink Jet Printer (EM-900C: manufactured by Seiko Epson Corporation). In plain paper clean mode, use plain paper (Xe
Rox P: manufactured by Xerox Co., Ltd.) was printed with 24 letters of the alphabet, and the appearance of bleeding was visually observed and evaluated according to the following criteria. The results are shown in Table 2. A: No bleeding occurred. B: Bleeding occurs slightly. C: Bleeding occurred frequently.

(5) Abrasion resistance The ink composition for ink jet recording prepared in Examples 1 to 6 and Comparative Examples 1 and 2 and Ink Jet Printer (MC-2000C: manufactured by Seiko Epson Corporation) were used. A line with a width of 2 mm is printed on MC photo paper (manufactured by Seiko Epson Co., Ltd.) and fine plain paper (KA4250NP: manufactured by Seiko Epson Co., Ltd.), and a yellow water-based highlighter pen (ZEBRA) is printed so as to be orthogonal to the line. PEN2: manufactured by Zebra) was rubbed with a load of 500 g over a length of 2 cm in the width direction of the line, and the rubbed portion was visually observed to evaluate the presence or absence of stains according to the following criteria. The results are shown in Table 2. A: No stain is generated. B: Slight stains of 1 mm or less are generated at several places in both the length direction and the width direction. C: Contamination occurs in the width of the highlighter pen.

(6) Quick Drying The ink compositions for ink jet recording prepared in Examples 1 to 6 and Comparative Examples 1 and 2 and Ink Jet Printer (MC-2000C: manufactured by Seiko Epson Corporation) were used. Solid printing on MC photo paper (manufactured by Seiko Epson Corporation), and after printing, plain paper (Xer
ox P: manufactured by Xerox Co., Ltd.) is overlaid, and 250 g /
When a load of cm ² was applied, the time required until the ink was not transferred to the paper was measured and evaluated according to the following criteria. The results are shown in Table 2. Evaluation A: Less than 10 seconds. Evaluation B: 10 seconds or more and less than 30 seconds. Evaluation C: 30 seconds or more.

[0107]

[Table 2]

[0108]

According to the present invention, the dispersibility in an aqueous system is excellent, the high printing density and the printing quality are excellent, the quick drying property is excellent, the abrasion resistance and the fixing property are excellent, and the water resistance and the light resistance are excellent. It is possible to provide a water-based ink composition capable of obtaining a recorded matter having excellent properties and chemical resistance.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) C08F 2/44 C08F 4/04 4J015 4/04 C09B 67/46 B 4J039 C09B 67/46 C09D 11/00 C09D 11/00 B41J 3/04 101Y // B01J 13/14 B01J 13/02 BF Term (reference) 2C056 EA13 FC02 2H086 BA01 BA53 BA55 BA56 BA59 4D077 AA08 AB05 AB13 AC05 BA20 DC01X DC02X DC04X DC19X DC59X 4G005 AA01 AB15 BA15 AB15 AB15 AB15 BB12 BB20 DA02X DC10Y DC22Y DC42Y DC52Y DD04Z DD07Z DD12Z DD52Z DD53Z DD56Z DD64Z DD66W DD70Z EA08 4J011 PA03 PA22 PB06 PB25 PC02 4J015 AA01 4J039 AD01 AD09 AE07 AE11 AE13 CA07 BC24 BC03 BC33 BC03

Claims (28)

[Claims] 1. A compound represented by the general formula (I): [Wherein D is a moiety containing at least a hydrophobic segment, L ¹ and L ² are linker groups which can be the same or different, and R ¹ , R ² , R ³ and R ⁴ are respectively Independently, it is an alkyl group having 1 to 4 carbon atoms or a cyano group, and n is an integer of 1 or more] in the presence of a polymeric azo initiator containing a repeating unit and a vinyl polymerizable dispersant. And under conditions in which the polymeric azo initiator is not activated,
A microencapsulated colorant obtained by dispersing a water-insoluble colorant and subsequently activating the polymer azo initiator to polymerize the vinyl-based polymerizable dispersant in the obtained dispersion liquid is obtained. An aqueous dispersion, comprising: 2. General formula (II): [In the formula, L ¹¹ and L ¹² can combine with the linking groups L ²¹ and L ²² in the general formula (III) described later to form the linker groups L ¹ and L ² in the general formula (I). And R ¹ , R ² , R ³ , and R ⁴ are each independently an alkyl group having 1 to 4 carbon atoms or a cyano group] and a general formula (III): L ²² -D-L ²¹ (III) [In the formula, L ²¹ and L ²² are bonded to the bonding groups L ¹¹ and L ¹² in the general formula (II) to form the linker group L ¹ in the general formula (I). And a group capable of forming L ² , and D is a portion containing at least a hydrophobic segment], the polymer azo initiator produced by polymerizing the compound is used. The aqueous dispersion described. 3. The polymer azo initiator according to claim 1, wherein the moiety D is a hydrophobic segment, and L ¹ and L ² are hydrophilic linker groups which may be the same or different. The aqueous dispersion described. 4. The portion D is represented by the general formula (11): -B ¹ -A ^1- (11) [wherein A ¹ is a hydrophilic segment and B ¹ is a hydrophobic segment]. The aqueous dispersion according to claim 1 or 2, which uses a high molecular weight azo initiator which is a part to be treated. 5. The moiety D is represented by the general formula (12): —A ² —B ² —A ³ — (12) [wherein A ² and A ³ are the same or different hydrophilic segments. And B ² is a hydrophobic segment]. The aqueous dispersion according to claim 1 or 2, wherein a polymer azo initiator which is a portion represented by the formula [2] is used. 6. The aqueous dispersion according to claim 3, wherein the hydrophilic linker group is an ester bond or an amide bond. 7. The hydrophobic segment is a polysiloxane segment, a polyaryl segment, a polyalkyl segment, or a polyalkylene oxide segment (provided that the alkylene portion has 3 or more carbon atoms). The aqueous dispersion according to any one of 1. 8. The polysiloxane segment has the general formula (13): [In the formula, R ⁶ , R ⁷ , R ⁸ , and R ⁹ are each independently an alkyl group having 1 to 4 carbon atoms or an aryl group having 6 to 10 carbon atoms, and d is 0 or 1 or more. Is an integer of
Is an integer of 1 or more], and the aqueous dispersion according to claim 7. 9. The aqueous dispersion according to claim 4, wherein the hydrophilic segment is a polyethylene oxide segment. 10. A moiety represented by the general formula (11) is represented by the general formula (11a): The aqueous dispersion according to claim 4, which is an ethylene oxide propylene oxide copolymer segment represented by the formula: wherein h and j are integers of 1 or more. 11. A moiety represented by the general formula (12) is represented by the general formula (12a): [Wherein, R ¹¹ and R ¹² are methyl groups, Y is an ethylene group, and a, b, and c are integers of 1 or more]. The aqueous dispersion according to claim 5, which is an oxyethylene) polydimethylsiloxane segment. 12. The polymeric azo initiator is represented by the general formula (I
a): [Wherein, R ¹ and R ³ are alkyl groups having 1 to 4 carbon atoms, R ² and R ⁴ are cyano groups, and R ⁶ , R ⁷ , R ⁸ and
And R ⁹ are each independently an alkyl group having 1 to 4 carbon atoms or an aryl group having 6 to 10 carbon atoms, and d is 0.
Or an integer of 1 or more, e, n, p, q, r, and s
Are each independently an integer of 1 or more], the aqueous dispersion according to any one of claims 1 to 3. 13. The polymeric azo initiator is represented by the general formula (I
b): [In the formula, R ¹ and R ³ are alkyl groups having 1 to 4 carbon atoms, R ² and R ⁴ are cyano groups, and R ¹¹ and R ¹² are
Each independently represents an alkyl group having 1 to 4 carbon atoms or an aryl group having 6 to 10 carbon atoms, and a, b, c, f, and g are integers of 1 or more] is there,
The aqueous dispersion according to claim 1. 14. The polymeric azo initiator is represented by the general formula (I
c): [In the formula, R ¹ and R ³ are alkyl groups having 1 to 4 carbon atoms, R ² and R ⁴ are cyano groups, and α, β, h, j,
And n are each independently an integer of 1 or more], The aqueous dispersion according to any one of claims 1 to 4 or 10. 15. The aqueous dispersion according to any one of claims 1 to 14, wherein the vinyl-based polymerizable dispersant is a compound containing at least a vinyl-based polymerizable group, a hydrophobic group and a hydrophilic group. liquid. 16. The aqueous dispersion according to claim 15, wherein the compound containing at least a vinyl-based polymerizable group, a hydrophobic group and a hydrophilic group is a polymerizable surfactant. 17. The vinyl-based polymerizable group is a vinyl group,
The aqueous dispersion according to claim 15 or 16, which is a group selected from the group consisting of an allyl group, an acryloyl group, a methacryloyl group, a propenyl group, a vinylidene group, and a vinylene group. 18. The hydrophilic group according to claim 15, wherein the hydrophilic group is a group selected from the group consisting of a sulfone group, a sulfonic acid group, a carboxyl group, a carbonyl group, and salts thereof. Aqueous dispersion of. 19. The aqueous dispersion according to claim 1, wherein the water-insoluble colorant is a pigment or an oil-soluble dye. 20. A vinyl-based polymerizable dispersant having a cross-linking reactive group is used as the vinyl-based polymerizable dispersant, and a cross-linking agent is present in addition to the vinyl-based polymerizable dispersant and the polymer azo initiator. The aqueous dispersion according to any one of claims 1 to 19, wherein the water-insoluble colorant is dispersed below and subsequently polymerized. 21. The crosslinkable group is a glycidyl group,
The aqueous dispersion according to claim 20, which is a group selected from the group consisting of an isocyanate group, a hydroxyl group, and a vinyl group. 22. The aqueous dispersion according to claim 20, wherein the cross-linking agent is a cross-linking agent having at least two functional groups that react with the cross-linking reactive group in the molecule. 23. The functional group of the crosslinking agent which reacts with the crosslinking reactive group is an amino group, a carboxyl group, a hydroxyl group, a carboxyl group, a mercapto group, a glycidyl group, an isocyanate group, an N-methylol group or an N-methylol ether. The aqueous dispersion according to claim 22, which is a group selected from the group consisting of a group and a vinyl group. 24. An aqueous ink composition comprising the aqueous dispersion according to any one of claims 1 to 23. 25. The water-based ink composition according to claim 24, which is for inkjet recording. 26. An ink jet recording method using the aqueous ink composition according to claim 25. 27. A recorded matter obtained by the inkjet recording method according to claim 26. 28. An inkjet recording ink set, comprising the water-based ink composition according to claim 25.