JP5897303B2 - Pigment for water-based ink - Google Patents

Description

  The present invention relates to a pigment for aqueous ink having excellent dispersion stability, an aqueous ink composition containing the pigment, an image thereof, and a printed matter.

  In recent years, inkjet printing has attracted attention as a method for forming images such as characters, pictures and designs on a substrate such as a transparent film. Inkjet printing is a printing method in which printing is performed by causing ink droplets to fly and adhere to a recording medium such as paper. When printing on such a substrate, it is necessary to conceal the substrate in order to improve the color of the printed matter. In order to conceal the base, it is common to use a white ink with high concealment, and an inorganic pigment, particularly titanium dioxide, is often used as the pigment. However, inorganic pigments such as titanium dioxide have a high specific gravity, and therefore, when used for inkjet inks having a low viscosity, suppression of pigment settling becomes a problem. When the pigment settles, there are problems such as clogging during ejection from the ink jet nozzle and poor storage stability of the ink. If the particle size of titanium dioxide is reduced in order to suppress pigment settling, the settling can be reduced, but since the white color developability is lowered, the hiding power is also lowered and the hiding power of the white ink is reduced. There is a problem that it falls dramatically. Patent Document 1 discloses that whiteness can be maintained and storage stability can be secured by using silica having a specific gravity smaller than that of titanium dioxide. However, silica is inferior in both whiteness and concealment compared to titanium dioxide, so that it is necessary to use titanium dioxide in combination, and as a result, it is difficult to ensure storage stability.

JP 2010-174100 A

  An object of the present invention is to provide a pigment for water-based ink that is difficult to settle in a water-based ink medium and has a good white color development property, a water-based ink composition containing the same, and an image and a printed matter obtained using the water-based ink composition. It is to provide.

That is, the present invention includes the following inventions.
[1] (A) In a matrix mainly composed of a metal oxide having a refractive index of 1.8 or more at a wavelength of 589.3 nm (Na-D line), a 50% volume particle size is 10 to 300 nm, and an aqueous medium is used. An organic-inorganic composite in which dispersible organic polymer particles are dispersed,
And / or (B) pores having an average pore diameter of 10 to 300 nm are dispersed in a matrix mainly composed of a metal oxide having a refractive index of 1.8 or more at a wavelength of 589.3 nm (Na-D line). A pigment for aqueous ink comprising a porous metal oxide.
[2] The pigment for water-based ink according to [1], wherein the particle size of (A) the organic-inorganic composite and / or (B) the metal oxide porous material is 0.1 μm to 5 μm.
[3] The aqueous ink pigment according to [1] or [2], wherein the metal oxide is titanium dioxide.
[4] The aqueous ink pigment according to any one of [1] to [3], wherein the metal oxide is formed from titanium dioxide nanoparticles having a surface coated with zirconium dioxide.
[5] The aqueous (B) metal oxide porous material according to any one of [1] to [4], which is obtained by removing organic polymer particles from the (A) organic-inorganic composite. Ink pigment.
[6] The pigment for water-based ink according to any one of [1] to [5], wherein the organic polymer particles and / or pores dispersed in the metal oxide have a cubic phase structure.
[7] The organic polymer particles are selected from polyolefin, poly (meth) acrylate, polystyrene, polyurethane, polyacrylonitrile, polyvinyl chloride, polyvinylidene chloride, polyvinyl acetate, and polybutadiene. The pigment for water-based ink according to any one of [1] to [6], which is at least one water-insoluble polymer particle.
[8] Any of [1] to [7], wherein the organic polymer particles are terminal branched polyolefin copolymer particles having a number average molecular weight of 2.5 × 10 ⁴ or less represented by the following general formula (1): Crab for water-based ink according to:

(In the formula, A represents a polyolefin chain. R ¹ and R ² represent a hydrogen atom or an alkyl group having 1 to 18 carbon atoms, and at least one of them is a hydrogen atom. X ¹ and X ² are the same. Or, differently, it represents a group having a linear or branched polyalkylene glycol group.

[9] In the terminal branched copolymer represented by the general formula (1), X ¹ and X ² are the same or different, and the general formula (2)

(In the formula, E represents an oxygen atom or a sulfur atom. X ³ represents a polyalkylene glycol group or the following general formula (3).

(In the formula, R ³ represents an m + 1 valent hydrocarbon group. G is the same or different and is represented by —OX ⁴ , —NX ⁵ X ⁶ (X ^{4 to} X ⁶ represent a polyalkylene glycol group). M represents the number of bonds between R ³ and G, and represents an integer of 1 to 10). )
Or general formula (4)

(Wherein X ⁷ and X ⁸ are the same or different and each represents a polyalkylene glycol group or a group represented by the above general formula (3)). Pigments.

[10] The pigment for water-based ink according to [8] or [9], wherein the terminally branched copolymer is represented by the following general formula (1a) or general formula (1b):

(In the formula, R ⁴ and R ⁵ represent a hydrogen atom or an alkyl group having 1 to 18 carbon atoms, and at least one of them is a hydrogen atom. R ⁶ and R ⁷ represent a hydrogen atom or a methyl group, At least one of them is a hydrogen atom, R ⁸ and R ⁹ represent a hydrogen atom or a methyl group, and at least one of them is a hydrogen atom, l + m represents an integer of 2 to 450, n is 20 Represents an integer of 300 or more.)

(In the formula, R ⁴ and R ⁵ represent a hydrogen atom or an alkyl group having 1 to 18 carbon atoms, and at least one of them is a hydrogen atom. R ⁶ and R ⁷ represent a hydrogen atom or a methyl group, At least one of them is a hydrogen atom, R ⁸ and R ⁹ represent a hydrogen atom or a methyl group, at least one of them is a hydrogen atom, R ¹⁰ and R ¹¹ represent a hydrogen atom or a methyl group, At least one of them is a hydrogen atom, l + m + o represents an integer of 3 to 450, and n represents an integer of 20 to 300.)

[11] The pigment for water-based ink according to any one of [1] to [7], wherein the organic polymer particles are (meth) acrylic acid ester polymer particles.
[12] A water-based ink composition comprising the water-based ink pigment according to any one of [1] to [11].
[13] The aqueous ink composition according to [12], which is for inkjet printing.
[14] Images of characters, pictures, designs, etc. recorded with the water-based ink composition according to [12] or [13].
[15] A printed matter printed on the substrate using the water-based ink composition according to [12] or [13].

  According to the present invention, the organic polymer particles dispersible in an aqueous medium having a specific gravity lower than that of the metal oxide are composited with the metal oxide, or by making the metal oxide porous, the bulk specific gravity is lowered, and precipitation is difficult. An aqueous pigment having excellent whiteness can be provided. The aqueous ink composition containing the aqueous pigment of the present invention is excellent in storage stability, and the coating film obtained from the composition is excellent in whiteness and / or hiding properties.

  The pigment for water-based ink, water-based ink composition, image obtained from the water-based ink composition, and printed matter of the present invention will be described in order.

1. Aqueous Ink Pigment The aqueous ink pigment of the present invention comprises (A) an organic-inorganic composite and / or (B) a metal oxide porous material.

1-1 (A) Organic-inorganic composite The organic-inorganic composite (A) of the present invention has organic polymer particles having a specific particle size dispersed in a matrix mainly composed of a metal oxide having a specific refractive index. .

(Metal oxide)
The principle that a powder of a substance that is originally transparent looks white is that light is irregularly reflected on the surface of the powder particles. In order to make the white pigment appear whiter, the efficiency of irregular reflection on the particle surface may be increased, and a material having a higher refractive index may be selected as a material. Examples of the material having a high refractive index include metal oxide particles having a refractive index of 1.8 or more at a wavelength of 589.3 nm (Na-D line) such as titanium dioxide. Specific examples of the metal oxide having a refractive index of 1.8 or more at a wavelength of 589.3 nm (Na-D line) include titanium dioxide (TiO ₂ : 2.2 to 2.7) and zirconium dioxide (ZrO ₂ ). : 2.1), yttria stabilized zirconium (YSZ: 2.1 to 2.2), indium oxide (In ₂ O ₃ : 2.0), zinc oxide (ZnO: 2.35), antimony oxide (Sb ₂₎ O ₅ : 2.0), tin oxide (SnO: 1.9), and barium titanate (BaTiO ₃ : 2.4). Moreover, it is preferable to use titanium dioxide whose surface is coated with zirconium dioxide because the photocatalytic activity of titanium dioxide can be suppressed and the light resistance of the resulting coating film is improved.

  Furthermore, when these metal oxides are used as inkjet pigments, the particle size of the pigment must be set in order to stably discharge the inkjet nozzles without clogging, and to maintain the whiteness and concealment of the coating film. It is preferable that the storage stability is ensured at 100 nm to 5 μm, particularly 200 nm to 1 μm. However, since the specific gravity of metal oxides such as titanium dioxide is generally high, a phenomenon in which the pigment settles and aggregates in the ink is observed in the particle size range. In the present invention, an organic pigment having a specific particle size is dispersed in a metal oxide to form a composite, whereby an aqueous pigment having a low bulk specific gravity and difficult to settle can be formed.

(Organic polymer particles)
The 50% volume particle size of the organic polymer particles of the present invention is 10 to 300 nm, preferably 10 to 200 nm.

 The content of the organic polymer particles of the present invention is not particularly limited. For example, the organic polymer particles / metal oxide (weight ratio) is 10/90 to 90/10, preferably 20/80 to 80/20. can do.

  The organic polymer particles preferably have a cubic phase structure and are dispersed in a matrix mainly composed of a metal oxide. By taking a cubic phase structure, it can be expected that the strength is higher than that of a hexagonal phase structure or a random (disordered) structure.

  The organic polymer particles of the present invention may be any particles that can be dispersed in an aqueous medium. For example, at least one water-insoluble material selected from polyolefin, poly (meth) acrylic acid ester, polystyrene, polyurethane, polyacrylonitrile, polyvinyl chloride, polyvinylidene chloride, polyvinyl acetate and polybutadiene There may be mentioned polymer particles. The aqueous medium is water and / or an organic solvent having an affinity for water.

 An organic-inorganic composite in which particles having a particle size of 10 to 30 nm are dispersed can be stably produced by using, for example, polyolefin-based terminally branched copolymer particles dispersed in an aqueous medium. In addition, an organic-inorganic composite in which particles of more than 30 nm and not more than 300 nm are dispersed can be stably produced by using, for example, poly (meth) acrylate polymer particles dispersed in an aqueous medium.

First, the polyolefin-based terminally branched copolymer particles will be described.
[Polyolefin end-branched copolymer]
The polyolefin terminal branched copolymer constituting the polymer particles used in the present invention has a structure represented by the following general formula (1).

(In the formula, A represents a polyolefin chain. R ¹ and R ² are a hydrogen atom or an alkyl group having 1 to 18 carbon atoms, and at least one of them is a hydrogen atom, and X ¹ and X ² are the same. Or, differently, it represents a group having a linear or branched polyalkylene glycol group.)

The number average molecular weight of the terminal branched copolymer represented by the general formula (1) is 2.5 × 10 ⁴ or less, preferably 5.5 × 10 ^{2 to} 1.5 × 10 ⁴ , more preferably 8 × 10. ^{2 to} 4.0 × 10 ³ . The number average molecular weight is the number average molecular weight of the polyolefin chain represented by A, the number average molecular weight of the group having a polyalkylene glycol group represented by X ¹ and X ² , and R ¹ , R ² and C ₂ H min. It is expressed as the sum of molecular weights.

  When the number average molecular weight of the polyolefin end-branched copolymer is in the above range, the stability of the particles in the dispersion when the polyolefin end-branched copolymer is used as a dispersoid, water and / or affinity with water This is preferable because the dispersibility of the organic solvent in the organic solvent tends to be good and the preparation of the dispersion becomes easy.

  The polyolefin chain which is A in the general formula (1) is obtained by polymerizing an olefin having 2 to 20 carbon atoms. Examples of the olefin having 2 to 20 carbon atoms include α-olefins such as ethylene, propylene, 1-butene and 1-hexene. In the present invention, it may be a homopolymer or copolymer of these olefins, and may be copolymerized with other polymerizable unsaturated compounds as long as the properties are not impaired. Among these olefins, ethylene, propylene, and 1-butene are particularly preferable.

  In general formula (1), the number average molecular weight measured by GPC of the polyolefin chain represented by A is 400 to 8000, preferably 500 to 4000, and more preferably 500 to 2000. Here, the number average molecular weight is a value in terms of polystyrene.

  When the number average molecular weight of the polyolefin chain represented by A is in the above range, the polyolefin portion has high crystallinity, the dispersion tends to be stable, and the melt viscosity is low and the preparation of the dispersion is easy. This is preferable.

  The ratio of the weight average molecular weight (Mw) and the number average molecular weight (Mn) measured by GPC of the polyolefin chain represented by A in the general formula (1), that is, the molecular weight distribution (Mw / Mn) is not particularly limited. However, it is usually 1.0 to several tens, more preferably 4.0 or less, and still more preferably 3.0 or less.

  When the molecular weight distribution (Mw / Mn) of the group represented by A in the general formula (1) is in the above range, it is preferable in terms of the shape of the particles in the dispersion and the uniformity of the particle diameter.

The number average molecular weight (Mn) and molecular weight distribution (Mw / Mn) of the group represented by A by GPC can be measured under the following conditions using, for example, GPC-150 manufactured by Millipore.
Separation column: TSK GNH HT (column size: diameter 7.5 mm, length: 300 mm)
Column temperature: 140 ° C
Mobile phase: Orthodichlorobenzene (Wako Pure Chemical Industries, Ltd.)
Antioxidant: Butylhydroxytoluene (manufactured by Takeda Pharmaceutical Company Limited) 0.025% by mass
Movement speed: 1.0 ml / min Sample concentration: 0.1% by mass
Sample injection volume: 500 microliters Detector: differential refractometer.

  The molecular weight of the polyolefin chain represented by A can be measured by measuring the molecular weight of a polyolefin having an unsaturated group at one terminal, which will be described later, and subtracting the molecular weight corresponding to the terminal.

R ¹ and R ² are each a hydrogen atom or a hydrocarbon group having 1 to 18 carbon atoms, which is a substituent bonded to a double bond of the polyolefin constituting A, preferably a hydrogen atom or 1 to 18 carbon atoms. It is an alkyl group. As the alkyl group, a methyl group, an ethyl group, and a propyl group are preferable.

In the general formula (1), X ¹ and X ² are the same or different and each represents a linear or branched group having a polyalkylene glycol group having a number average molecular weight of 50 to 10,000. The branching mode of the branched alkylene glycol group includes a branching via a polyvalent hydrocarbon group or a nitrogen atom. For example, branching by a hydrocarbon group bonded to two or more nitrogen atoms, oxygen atoms or sulfur atoms in addition to the main skeleton, branching by a nitrogen atom bonded to two alkylene groups in addition to the main skeleton, and the like can be given.

  It is preferable that the number average molecular weight of the group having a polyalkylene glycol group is in the above range because the dispersibility of the dispersion tends to be good and the melt viscosity is low and the preparation of the dispersion is easy.

Since X ¹ and X ^{2 in} the general formula (1) have the above-described structure, a polyolefin end-branched copolymer having a 50% volume average particle diameter of 10 nm to 30 nm without using a surfactant is used. Polymer particles made of a polymer can be obtained stably.

In the general formula (1), preferred examples of X ¹ and X ² are the same or different from each other, and the general formula (2),

(In the formula, E represents an oxygen atom or a sulfur atom, X ³ represents a polyalkylene glycol group, or the following general formula (3)

(Wherein R ³ represents an m + 1 valent hydrocarbon group, G is the same or different, and is represented by —OX ⁴ , —NX ⁵ X ⁶ (X ^{4 to} X ⁶ represent a polyalkylene glycol group). M represents the number of bonds between R ³ and G, and represents an integer of 1 to 10.). )
Or general formula (4)

(Wherein X ⁷ and X ⁸ are the same or different and represent a polyalkylene glycol group or a group represented by the above general formula (3)).

In the general formula (3), the group represented by R ³ is an m + 1 valent hydrocarbon group having 1 to 20 carbon atoms. m is 1-10, 1-6 are preferable and 1-2 are especially preferable.

As a preferred example of the general formula (1), there is a polyolefin terminal branched copolymer in which either X ¹ or X ² is a group represented by the general formula (4) in the general formula (1). Can be mentioned. More preferable examples include polyolefin-based terminally branched copolymers in which ^one of X ¹ and X ² is represented by the general formula (4) and the other is a group represented by the general formula (2). It is done.

As another preferable example of the general formula (1), ^one of X ¹ and X ^{2 in} the general formula (1) is a group represented by the general formula (2), and more preferably X ¹ and X ^2. And polyolefin-based terminally branched copolymers in which both are groups represented by the general formula (2).
As a more preferable structure of X ¹ and X ² represented by the general formula (4), the general formula (5)

(Wherein X ⁹ and X ¹⁰ are the same or different and represent a polyalkylene glycol group, and Q ¹ and Q ² are the same or different and each represents a divalent hydrocarbon group). is there.

The divalent hydrocarbon group represented by Q ¹ and Q ² in the general formula (5) is preferably a divalent alkylene group, and more preferably an alkylene group having 2 to 20 carbon atoms. The alkylene group having 2 to 20 carbon atoms may or may not have a substituent, for example, ethylene group, methylethylene group, ethylethylene group, dimethylethylene group, phenylethylene group, chloromethylethylene group, bromo Examples thereof include a methylethylene group, a methoxymethylethylene group, an aryloxymethylethylene group, a propylene group, a trimethylene group, a tetramethylene group, a hexamethylene group, and a cyclohexylene group. A preferable alkylene group is a hydrocarbon-based alkylene group, particularly preferably an ethylene group or a methylethylene group, and still more preferably an ethylene group. Q ¹ and Q ² may be one kind of alkylene group, or two or more kinds of alkylene groups may be mixed.
As a more preferable structure of X ¹ and X ² represented by the general formula (2), the general formula (6)

(Wherein X ¹¹ represents a polyalkylene glycol group).

The polyalkylene glycol group represented by X ^{3 to} X ¹¹ is a group obtained by addition polymerization of alkylene oxide. Examples of the alkylene oxide constituting the polyalkylene glycol group represented by X ^{3 to} X ¹¹ include ethylene oxide, propylene oxide, butylene oxide, styrene oxide, cyclohexene oxide, epichlorohydrin, epibromohydrin, methyl glycidyl ether, allyl A glycidyl ether etc. are mentioned. Of these, propylene oxide, ethylene oxide, butylene oxide, and styrene oxide are preferable. More preferred are propylene oxide and ethylene oxide, and particularly preferred is ethylene oxide. The polyalkylene glycol group represented by X ^{3 to} X ¹¹ may be a group obtained by homopolymerization of these alkylene oxides or a group obtained by copolymerization of two or more kinds. Examples of preferred polyalkylene glycol groups are polyethylene glycol groups, polypropylene glycol groups, or groups obtained by copolymerization of polyethylene oxide and polypropylene oxide, and particularly preferred groups are polyethylene glycol groups.

When X ¹ and X ² in the general formula (1) have the above structure, water and / or an organic solvent having an affinity for water when the polyolefin end-branched copolymer of the present invention is used as a dispersoid. Since dispersibility becomes favorable, it is preferable.

  As the polyolefin-based terminally branched copolymer that can be used in the present invention, a polymer represented by the following general formula (1a) or (1b) is preferably used.

In the formula, R ⁴ and R ⁵ represent a hydrogen atom or an alkyl group having 1 to 18 carbon atoms, and at least one of them is a hydrogen atom. As the alkyl group, an alkyl group having 1 to 9 carbon atoms is preferable, and an alkyl group having 1 to 3 carbon atoms is more preferable.

R ⁶ and R ⁷ represent a hydrogen atom or a methyl group, and at least one of them is a hydrogen atom. R ⁸ and R ⁹ represent a hydrogen atom or a methyl group, and at least one of them is a hydrogen atom.
l + m represents an integer of 2 to 450, preferably 5 to 200.
n represents an integer of 20 or more and 300 or less, preferably 25 or more and 200 or less.

In the formula, R ⁴ and R ⁵ represent a hydrogen atom or an alkyl group having 1 to 18 carbon atoms, and at least one of them is a hydrogen atom. As the alkyl group, an alkyl group having 1 to 9 carbon atoms is preferable, and an alkyl group having 1 to 3 carbon atoms is more preferable.

R ⁶ and R ⁷ represent a hydrogen atom or a methyl group, and at least one of them is a hydrogen atom. R ⁸ and R ⁹ represent a hydrogen atom or a methyl group, and at least one of them is a hydrogen atom. R ¹⁰ and R ¹¹ represent a hydrogen atom or a methyl group, and at least one of them is a hydrogen atom.
l + m + o represents an integer of 3 to 450, preferably 5 to 200.
n represents an integer of 20 to 300, preferably 25 to 200.

  As the polymer represented by the general formula (1b), it is more preferable to use a polymer represented by the following general formula (1c).

In the formula, l + m + o and n are the same as those in the general formula (1b).
The number of ethylene units (n) of the polyethylene chain can be calculated by dividing the number average molecular weight (Mn) of the polyolefin group A in the general formula (1) by the molecular weight of the ethylene unit. The total number of ethylene glycol units (l + m or l + m + o) of the polyethylene glycol chain is such that the weight ratio of the polymer raw material to the ethylene oxide used during the polyethylene glycol group addition reaction is the number average molecular weight of the polymer raw material and the polyethylene glycol group (Mn ) And the ratio can be calculated.

N, l + m or l + m + o can also be measured by ¹ H-NMR. For example, in the polyolefin-based terminally branched copolymer (T) used in the examples of the present invention and the dispersion particles containing the same, the terminal methyl group of the polyolefin group A in the general formula (1) (shift value: 0.88 ppm) ) And the integral value of the methylene group of polyolefin group A (shift value: 1.06-1.50 ppm) and the alkylene group of PEG (shift value: 3.33-3.72 ppm) when the integral value of 3 protons is taken. ) Can be calculated from the integral value.

  Specifically, since the molecular weight of the methyl group is 15, the molecular weight of the methylene group is 14, and the molecular weight of the ethylene oxide group is 44, the number average molecular weights of the polyolefin group A and the alkylene group can be calculated from the values of the integrated values. . By dividing the number average molecular weight of the polyolefin group A thus obtained by the molecular weight of the ethylene unit, n is divided by the number average molecular weight of the alkylene group by the molecular weight of the ethylene glycol unit, whereby the total number of ethylene glycol units (l + m Alternatively, l + m + o) can be calculated.

When the polyolefin group A is composed of an ethylene-propylene copolymer, n and l + m or l + m + o can be obtained by using both the propylene content that can be measured by IR, ¹³ C-NMR, and the integral value in ¹ H-NMR. Can be calculated. ^{In 1} H-NMR, a method using an internal standard is also effective.

[Production method of polyolefin end-branched copolymer]
The polyolefin-based terminally branched copolymer can be produced by the following method.

  First, in the target polyolefin-based terminally branched copolymer, as a polymer corresponding to the structure of A represented by the general formula (1), the general formula (7)

(Wherein A represents a polyolefin chain, R ¹ and R ² are a hydrogen atom or an alkyl group having 1 to 18 carbon atoms, and at least one of them represents a hydrogen atom.) A polyolefin having a double bond is produced.

This polyolefin can be produced by the following method.
(1) A transition metal compound having a salicylaldoimine ligand as shown in JP-A Nos. 2000-239312, 2001-27331, 2003-73412, etc. is used as a polymerization catalyst. Polymerization method.
(2) A polymerization method using a titanium catalyst comprising a titanium compound and an organoaluminum compound.
(3) A polymerization method using a vanadium catalyst comprising a vanadium compound and an organoaluminum compound.
(4) A polymerization method using a Ziegler-type catalyst comprising a metallocene compound such as zirconocene and an organoaluminum oxy compound (aluminoxane).

  Among the above methods (1) to (4), particularly according to the method (1), the polyolefin can be produced with high yield. In the method (1), a polyolefin having a double bond at one end is produced by polymerizing or copolymerizing the above-described polyolefin in the presence of the transition metal compound having the salicylaldoimine ligand. Can do.

  The polymerization of the polyolefin by the method (1) can be carried out by either a liquid phase polymerization method such as solution polymerization or suspension polymerization or a gas phase polymerization method. Detailed conditions and the like are already known, and the above-mentioned patent documents can be referred to.

  The molecular weight of the polyolefin obtained by the method (1) can be adjusted by allowing hydrogen to be present in the polymerization system, changing the polymerization temperature, or changing the type of catalyst used.

  Next, the polyolefin is epoxidized, that is, the double bond at the terminal of the polyolefin is oxidized to obtain a polymer containing an epoxy group at the terminal represented by the general formula (8).

(In the formula, A, R ¹ and R ² are as described above.)

Although the epoxidation method is not particularly limited, the following methods can be exemplified.
(1) Oxidation with peracids such as performic acid, peracetic acid, perbenzoic acid (2) Oxidation with titanosilicate and hydrogen peroxide (3) Oxidation with rhenium oxide catalyst such as methyltrioxorhenium and hydrogen peroxide ( 4) Oxidation with a porphyrin complex catalyst such as manganese porphyrin or iron porphyrin and hydrogen peroxide or hypochlorite (5) Salen complex such as manganese Salen and oxidation with hydrogen peroxide or hypochlorite (6) Manganese- Oxidation with a TACN complex such as a triazacyclononane (TACN) complex and hydrogen peroxide (7) Oxidation with hydrogen peroxide in the presence of a group VI transition metal catalyst such as a tungsten compound and a phase transfer catalyst The above (1) to (7) Among these methods, the methods (1) and (7) are particularly preferable in terms of the active surface.

For example, VIKOLOX ^™ (registered trademark, manufactured by Arkema) can be used as a low molecular weight terminal epoxy group-containing polymer having a Mw of about 400 to 600.

By reacting the terminal epoxy group-containing polymer represented by the general formula (8) obtained by the above-mentioned method with various reaction reagents, the polymer terminal α, β-position represented by the general formula (9) A polymer (polymer (I)) into which various substituents Y ¹ and Y ² are introduced can be obtained.

(In the formula, A, R ¹ and R ² are as described above. Y ¹ and Y ² are the same or different and represent a hydroxyl group, an amino group, or the following general formulas (10a) to (10c).)

(In the general formulas (10a) to (10c), E represents an oxygen atom or a sulfur atom, R ³ represents an m + 1 valent hydrocarbon group, T represents the same or different hydroxyl group and amino group, and m represents 1 -10
Represents an integer. )

For example, by hydrolyzing the terminal epoxy group-containing polymer represented by the general formula (8), a polymer in which both Y ¹ and Y ² are hydroxyl groups in the general formula (9) is obtained, and ammonia is reacted. By doing so, a polymer in which ^one of Y ¹ and Y ² is an amino group and the other is a hydroxyl group is obtained.

Further, by reacting the terminal epoxy group-containing polymer represented by the general formula (8) with the reaction reagent A represented by the general formula (11a), ^one of Y ¹ and Y ² in the general formula (9) A polymer having a group represented by the general formula (10a) and the other hydroxyl group is obtained.

(In the formula, E, R ³ , T and m are as described above.)

Further, by reacting the terminal epoxy group-containing polymer with the reaction reagent B represented by the general formulas (11b) and (11c), ^one of Y ¹ and Y ² in the general formula (9) is represented by the general formula (10b) or A polymer having the group shown in (10c) and the other hydroxyl group is obtained.

(Wherein R ³ , T and m are as described above.)

  Examples of the reaction reagent A represented by the general formula (11a) include glycerin, pentaerythritol, butanetriol, dipentaerythritol, polypentaerythritol, dihydroxybenzene, and trihydroxybenzene.

  Examples of the reaction reagent B represented by the general formulas (11b) and (11c) include ethanolamine, diethanolamine, aminophenol, hexamethyleneimine, ethylenediamine, diaminopropane, diaminobutane, diethylenetriamine, N- (aminoethyl) propanediamine, and imino. Bispropylamine, spermidine, spermine, triethylenetetramine, polyethyleneimine and the like can be mentioned.

  Addition reactions of epoxy compounds with alcohols and amines are well known and can be easily performed by ordinary methods.

  The general formula (1) can be produced by addition polymerization of alkylene oxide using the polymer (I) represented by the general formula (9) as a raw material. Examples of the alkylene oxide include propylene oxide, ethylene oxide, butylene oxide, styrene oxide, cyclohexene oxide, epichlorohydrin, epibromohydrin, methyl glycidyl ether, and allyl glycidyl ether. Two or more of these may be used in combination. Of these, propylene oxide, ethylene oxide, butylene oxide, and styrene oxide are preferable. More preferred are propylene oxide and ethylene oxide.

For the catalyst, polymerization conditions, etc., known ring-opening polymerization methods of alkylene oxides can be used. For example, Takayuki Otsu, “Chemistry of Revised Polymer Synthesis”, Kagaku Dojin, January 1971, p. . 172-180 discloses an example in which a polyol is obtained by polymerizing various monomers. Catalysts used for ring-opening polymerization include Lewis acids such as AlCl ₃ , SbCl ₅ , BF ₃ , and FeCl ₃ for cationic polymerization and alkali metal hydroxides for anionic polymerization as disclosed in the above document. Alternatively, alkaline earth metal oxides, carbonates, alkoxides, or alkoxides such as Al, Zn, and Fe can be used for alkoxides, amines, phosphazene catalysts, and coordination anionic polymerization. Here, as the phosphazene catalyst, for example, an anion of a compound disclosed in JP-A-10-77289, specifically, a commercially available tetrakis [tris (dimethylamino) phosphoranylideneamino] phosphonium chloride is alkalinized. The thing made into the alkoxy anion using the metal alkoxide etc. can be utilized.

  When a reaction solvent is used, the polymer (I) can be inert to the alkylene oxide, alicyclic hydrocarbons such as n-hexane and cyclohexane, and aromatic hydrocarbons such as toluene and xylene. And ethers such as dioxane, and halogenated hydrocarbons such as dichlorobenzene.

Except for the phosphazene catalyst, the catalyst is used in an amount of preferably 0.05 to 5 mol, more preferably 0.1 to 3 mol, relative to 1 mol of the starting polymer (I). The amount of phosphazene catalyst, polymerization rate, in terms of economy and the like, preferably 1 × ¹⁰ -4 ~5 × ^{10 -1} moles per mole of the polymer (I), more preferably 5 × 10 ^{- 4} to 1 × 10 ⁻¹ mol.

  The reaction temperature is usually 25 to 180 ° C., preferably 50 to 150 ° C., and the reaction time varies depending on the reaction conditions such as the amount of catalyst used, reaction temperature, reactivity of polyolefins, etc., but is usually several minutes to 50 hours. .

  As described above, the number average molecular weight of the general formula (1) depends on the method of calculating from the number average molecular weight of the polymer (I) represented by the general formula (8) and the weight of the alkylene oxide to be polymerized, or a method using NMR. Can be calculated.

[Polymer particles]
The polymer particles of the present invention comprising such a polyolefin end-branched copolymer have a structure in which the polyolefin chain portion represented by A in the general formula (1) is oriented in the inward direction. This is a rigid particle having a crystalline part.

  The polymer particles of the present invention can be dispersed again in a liquid such as a solvent even after removal of the particles by drying the dispersion because the polyolefin chain portion has crystallinity. The polymer particles of the present invention are rigid particles in which the melting point of the polyolefin chain portion contained in the particles is preferably 80 ° C. or higher, more preferably 90 ° C. or higher.

  When the melting point of the polyolefin chain part is in the above range, the particles have good crystallinity, and even when heated at a higher temperature, the particles are prevented from collapsing.

  For this reason, since the collapse of the particles is suppressed in the manufacturing process and use scenes in various applications described later, the characteristics of the polymer particles of the present invention are not lost, and the product yield and the product quality are more stable. .

  Even when the polymer particles of the present invention are dispersed in a solvent or the like, the particle diameter is constant regardless of the dilution concentration. That is, since it has redispersibility and a uniform dispersed particle size, it is different from micelle particles dispersed in a liquid.

[Polyolefin end-branched copolymer particle dispersion]
The dispersion of the present invention contains the above-mentioned polyolefin-based terminally branched copolymer in a dispersoid, and the dispersoid is dispersed as particles in water and / or an organic solvent having an affinity for water.

In the present invention, the dispersion is a dispersion obtained by dispersing polyolefin terminal branched copolymer particles,
(1) A dispersion containing the polymer particles, which is obtained when producing polyolefin-based terminally branched copolymer particles,
(2) A dispersion obtained by dispersing or dissolving other dispersoids, additives, and the like in the dispersion containing the polymer particles obtained when the polyolefin-based terminally branched copolymer particles are produced,
(3) A dispersion obtained by dispersing polyolefin-based terminally branched copolymer particles in water or an organic solvent having an affinity for water, and dispersing or dissolving other dispersoids or additives,
Any of these are included.

  The content of the polyolefin-based terminally branched copolymer in the dispersion of the present invention is preferably 0.1 to 50% by mass, more preferably 1 to 40% by mass when the total dispersion is 100% by mass. More preferably, it is 1-20 mass%.

It is preferable that the content ratio of the polyolefin-based terminally branched copolymer is in the above range because the practicality of the dispersion is good, the viscosity can be kept appropriate, and handling becomes easy.
The 50% volume average particle diameter of the particles in the dispersion of the present invention is preferably 10 nm or more and 30 nm or less.

  The 50% volume average particle size of the particles can be adjusted by changing the structure of the polyolefin portion and the structure of the terminal branch portion of the polyolefin-based terminal branched copolymer.

  The 50% volume average particle diameter in the present invention means the diameter of a particle when the total volume is 100% when the total volume is 100%, and is a dynamic light scattering particle size distribution measuring device or a microtrack particle size. It can be measured using a distribution measuring device.

  The shape can be observed with a transmission electron microscope (TEM) after negative staining with, for example, phosphotungstic acid.

  The dispersion in the present invention can be obtained by dispersing the polyolefin-based terminally branched copolymer in water and / or an organic solvent having an affinity for water.

  Dispersion in the present invention can be carried out by a method of physically dispersing a polyolefin-based terminally branched copolymer in water and / or an organic solvent having an affinity for water by mechanical shearing force.

  The dispersion method is not particularly limited, but various dispersion methods can be used. Specifically, the polyolefin-based terminally branched copolymer represented by the general formula (1) and water and / or an organic solvent having an affinity for water are mixed and then melted to obtain a high-pressure homogenizer, Examples thereof include a method of dispersing with a homomixer, an extrusion kneader, an autoclave, a method of spraying and pulverizing at a high pressure, and a method of spraying from pores. In addition, after dissolving the polyolefin-based terminally branched copolymer in a solvent other than water in advance, it is mixed with water and / or an organic solvent having an affinity for water and dispersed with a high-pressure homogenizer, a high-pressure homomixer, or the like. A method is also possible. At this time, the solvent used for dissolving the polyolefin end-branched copolymer is not particularly limited as long as the polyolefin end-branched copolymer dissolves, but has an affinity for toluene, cyclohexane or the above water. An organic solvent etc. are mentioned. When it is not preferable that an organic solvent other than water is mixed in the dispersion, it can be removed by an operation such as distillation.

  More specifically, for example, in an autoclave equipped with a stirrer capable of applying a shearing force, a dispersion is obtained by heating and stirring while applying a shearing force at a temperature of 100 ° C. or higher, preferably 120 to 200 ° C. be able to.

  When the temperature is within the above temperature range, the polyolefin end-branched copolymer is in a molten state, so that it can be easily dispersed, and the polyolefin end-branched copolymer is not easily deteriorated by heating.

  The time required for dispersion varies depending on the dispersion temperature and other dispersion conditions, but is about 1 to 300 minutes.

  The above stirring time is preferable because dispersion can be sufficiently performed and the polyolefin-based terminally branched copolymer is hardly deteriorated. After the reaction, it is preferable to maintain a state in which shearing force is applied until the temperature in the dispersion becomes 100 ° C. or lower, preferably 60 ° C. or lower.

  In the production of the dispersion used in the present invention, addition of a surfactant is not indispensable, but for example, an anionic surfactant, a cationic surfactant, an amphoteric surfactant, a nonionic surfactant and the like may coexist.

  Anionic surfactants include, for example, carboxylates, simple alkyl sulfonates, modified alkyl sulfonates, alkyl allyl sulfonates, alkyl sulfate esters, sulfated oils, sulfate esters, sulfated fatty acid monoglycerides, sulfated alkanol amides. Sulphated ethers, alkyl phosphate esters, alkyl benzene phosphonates, naphthalene sulfonic acid / formalin condensates.

  Examples of cationic surfactants include simple amine salts, modified amine salts, tetraalkyl quaternary ammonium salts, modified trialkyl quaternary ammonium salts, trialkyl benzyl quaternary ammonium salts, and modified trialkyl benzyl quaternary salts. Examples include quaternary ammonium salts, alkyl pyridinium salts, modified alkyl pyridinium salts, alkyl quinolinium salts, alkyl phosphonium salts, and alkyl sulfonium salts.

  Examples of amphoteric surfactants include betaine, sulfobetaine, sulfate betaine and the like.

Nonionic surfactants include, for example, fatty acid monoglycerin ester, fatty acid polyglycol ester, fatty acid sorbitan ester, fatty acid sucrose ester, fatty acid alkanol amide, fatty acid polyethylene glycol glycol condensate, fatty acid amide polyethylene glycol condensate, Examples include fatty acid alcohol / polyethylene / glycol condensate, fatty acid amine / polyethylene / glycol condensate, fatty acid mercaptan / polyethylene / glycol condensate, alkyl / phenol / polyethylene / glycol condensate, and polypropylene / glycol / polyethylene / glycol condensate. .
These surfactants can be used alone or in combination of two or more.

  In the production of the dispersion used in the present invention, a filtration step may be provided in the process for the purpose of removing foreign substances and the like. In such a case, for example, a stainless steel filter (wire diameter 0.035 mm, plain weave) of about 300 mesh may be installed and pressure filtration (air pressure 0.2 MPa) may be performed.

  The dispersion obtained by the above method has a pH of 1 by adding various acids and bases, for example, acids such as hydrochloric acid, sulfuric acid and phosphoric acid, and bases such as potassium hydroxide, sodium hydroxide and calcium hydroxide. No change or aggregation occurs from 13 to 13. In addition, the dispersion does not aggregate or precipitate even in a wide temperature range in which heating and refluxing or freezing and thawing are repeated under normal pressure.

  The water in the above method is not particularly limited, and distilled water, ion exchange water, city water, industrial water, and the like can be used, but it is preferable to use distilled water or ion exchange water.

  In addition, the organic solvent having an affinity for water in the above method is not particularly limited as long as the dispersoid such as polyolefin-based branched branched copolymer particles and surfactant can be dispersed. Examples include ethylene glycol, isopropyl alcohol, acetone, acetonitrile, methanol, ethanol, dimethyl sulfoxide, dimethylformamide, and dimethylimidazolidinone. When mixing of the organic solvent into the dispersion is not preferred, the organic solvent can be removed by distillation or the like after preparing a dispersion containing the dispersoid.

  In the dispersion according to the present invention, when the polyolefin terminal branched copolymer is 100 parts by mass, the dispersoid other than the polyolefin terminal branched copolymer is 0.001 part by mass to 20 parts by mass, preferably 0.01 mass part-10 mass parts, More preferably, 0.1 mass part-5 mass parts can be contained.

It is preferable that the content of the dispersoid be in the above range since the physical properties of the dispersion are good in practical use and the dispersion is less likely to aggregate and precipitate.
An organic-inorganic composite in which organic polymer particles having a particle size exceeding 30 nm and not more than 300 nm are dispersed can be stably produced by using, for example, poly (meth) acrylate polymer particles dispersed in an aqueous medium.

Next, the poly (meth) acrylate polymer particles will be described.
[(Meth) acrylic acid ester polymer particle aqueous dispersion]
The poly (meth) acrylate polymer is a homopolymer or copolymer having a repeating unit derived from an acrylate ester and / or a methacrylic ester.
An aqueous dispersion of poly (meth) acrylic acid ester polymer particles is generally called an acrylic emulsion and can be obtained by a known emulsion polymerization method. For example, it can be obtained by emulsion polymerization of an unsaturated monomer (such as an unsaturated vinyl monomer) in water containing a polymerization initiator and a surfactant.

  Specific examples of the acrylic ester include methyl acrylate, ethyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, n-amyl acrylate, isoamyl acrylate, n-hexyl acrylate, 2-ethylhexyl acrylate, octyl acrylate, Examples include decyl acrylate, dodecyl acrylate, octadecyl acrylate, cyclohexyl acrylate, phenyl acrylate, benzyl acrylate, and glycidyl acrylate.

  Specific examples of the methacrylic acid ester include methyl methacrylate, ethyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-amyl methacrylate, isoamyl methacrylate, n-hexyl methacrylate, 2-ethylhexyl methacrylate, octyl methacrylate, decyl methacrylate. , Dodecyl methacrylate, octadecyl methacrylate, cyclohexyl methacrylate, phenyl methacrylate, benzyl methacrylate, glycidyl methacrylate and the like.

  The poly (meth) acrylic acid ester polymer of the present invention may be copolymerized with an unsaturated monomer other than acrylic acid ester and methacrylic acid ester.

  Unsaturated monomers that can be used in combination include vinyl esters such as vinyl acetate; vinylcyan compounds such as acrylonitrile and methacrylonitrile; halogenated monomers such as vinylidene chloride and vinyl chloride; styrene, α-methylstyrene , Vinyltoluene, 4-t-butylstyrene, chlorostyrene, vinylanisole, vinylnaphthalene and other aromatic vinyl monomers; ethylene, propylene and other olefins; butadiene, chloroprene and other dienes; vinyl ether, vinyl ketone and vinyl Vinyl monomers such as pyrrolidone; unsaturated carboxylic acids such as acrylic acid, methacrylic acid, itaconic acid, fumaric acid and maleic acid; acrylamides such as acrylamide, methacrylamide and N, N′-dimethylacrylamide; 2-hydroxy Ethyl acrylate , 2-hydroxypropyl acrylate, 2-hydroxyethyl methacrylate, hydroxyl group-containing monomers such as 2-hydroxypropyl methacrylate and the like, can be used as a mixture thereof alone or two or more.

  A crosslinkable monomer having two or more polymerizable double bonds can also be used. Examples of the crosslinkable monomer having two or more polymerizable double bonds include polyethylene glycol diacrylate, triethylene glycol diacrylate, 1,3-butylene glycol diacrylate, 1,4-butylene glycol diacrylate, 1,6-hexanediol diacrylate, neopentyl glycol diacrylate, 1,9-nonanediol diacrylate, polypropylene glycol diacrylate, 2,2′-bis (4-acryloxypropyloxyphenyl) propane, 2,2 ′ -Diacrylate compounds such as bis (4-acryloxydiethoxyphenyl) propane, triacrylate compounds such as trimethylolpropane triacrylate, trimethylolethane triacrylate, tetramethylolmethane triacrylate , Tetraacrylate compounds such as ditrimethylol tetraacrylate, tetramethylol methane tetraacrylate, pentaerythritol tetraacrylate, hexaacrylate compounds such as dipentaerythritol hexaacrylate, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, polyethylene glycol Dimethacrylate, 1,3-butylene glycol dimethacrylate, 1,4-butylene glycol dimethacrylate, 1,6-hexanediol dimethacrylate, neopentyl glycol dimethacrylate, dipropylene glycol dimethacrylate, polypropylene glycol dimethacrylate, polybutylene glycol Dimethacrylate, , 2′-bis (4-methacryloxydiethoxyphenyl) propane and other dimethacrylate compounds, trimethylolpropane trimethacrylate, trimethylolethane trimethacrylate and other trimethacrylate compounds, methylenebisacrylamide, divinylbenzene and the like. Can be used alone or in admixture of two or more.

In addition to the polymerization initiator and surfactant used in emulsion polymerization, a chain transfer agent, further a neutralizing agent, and the like may be used according to a conventional method. In particular, ammonia and inorganic alkali hydroxides such as sodium hydroxide and potassium hydroxide are preferred as the neutralizing agent.
From the viewpoint of dispersion stability in water, the average particle size of the poly (meth) acrylic acid polymer particles is preferably more than 30 nm and not more than 300 nm, more preferably 40 to 250 nm, and particularly preferably 50 to 200 nm. It is preferable.

  Moreover, as a poly (meth) acrylic-acid type polymer particle, any of a single phase structure and a multiphase structure (core shell type) can be used.

The term “acrylic emulsion” is intended to include a solid / liquid dispersion called dispersion, latex, or suspension.
An acrylic emulsion is manufactured as follows, for example.

[Example of production method of acrylic emulsion]
In a reaction vessel equipped with a dropping device, a thermometer, a water-cooled reflux condenser and a stirrer, 100 parts of ion-exchanged water is added, and 0.2 part of a polymerization initiator is added while stirring at a temperature of 70 ° C. in a nitrogen atmosphere. To this, a separately prepared monomer solution is dropped and subjected to a polymerization reaction to prepare a primary substance. Thereafter, at a temperature of 70 ° C., 2 parts of a 10% aqueous solution of a polymerization initiator is added to the primary substance and stirred, and a separately prepared reaction solution is added and stirred to cause a polymerization reaction to obtain a polymerization reaction product. . The polymerization reaction product may be used as it is, or it may be neutralized with a neutralizing agent and adjusted to have a pH of 8 to 8.5. Thereafter, it is filtered through a filter to remove coarse particles, and an acrylic emulsion having resin particles as a dispersoid is obtained.

As the polymerization initiator, those used for normal radical polymerization are used, for example, potassium persulfate, ammonium persulfate, hydrogen peroxide, azobisisobutyronitrile, benzoyl peroxide, dibutyl peroxide, Examples include peracetic acid, cumene hydroperoxide, t-butyl hydroxy peroxide, paramentane hydroxy peroxide, and the like. In particular, as described above, when the polymerization reaction is performed in water, a water-soluble polymerization initiator is preferable.
Moreover, as an emulsifier used by a polymerization reaction, what is generally used as an anionic surfactant, a nonionic surfactant, or an amphoteric surfactant other than sodium lauryl sulfate is mentioned, for example.

Examples of the chain transfer agent used in the polymerization reaction include t-dodecyl mercaptan, n-dodecyl mercaptan, n-octyl mercaptan, xanthogens such as dimethylxanthogen disulfide, diisobutylxanthogen disulfide, dipentene, indene, 1,4- Examples include cyclohexadiene, dihydrofuran, and xanthene.
The acrylic emulsion can be used in combination with an organic solvent in addition to water. As such an organic solvent, those having compatibility with water are preferable. For example, alkyl alcohols having 1 to 4 carbon atoms such as ethanol, methanol, butanol, propanol, isopropanol, ethylene glycol monomethyl ether, ethylene glycol monoethyl, and the like. 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, ethylene glycol mono-t-butyl ether, polyethylene Glycol mono-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- Glycol ethers such as propyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol mono-n-propyl ether, dipropylene glycol mono-iso-propyl ether, 2-pyrrolidone, formamide, acetamide, dimethyl Examples include sulfoxide, sorbit, sorbitan, acetin, diacetin, triacetin, and sulfolane. It can be used alone or in combination of two or more of al.

1-2 (B) Metal oxide porous body The (B) metal oxide porous body of the present invention comprises a metal oxide having a refractive index of 1.8 or more at a wavelength of 589.3 nm (Na-D line). In the main matrix, pores having an average pore size of 10 to 300 nm are dispersed.

(Metal oxide)
As a metal oxide, the metal oxide illustrated by said (A) can be mentioned.
In the present invention, since the pores having a specific pore diameter are dispersed in the metal oxide, the bulk specific gravity is lowered, and an aqueous pigment that is difficult to settle can be formed.

(pore)
(B) The average pore diameter of the pores in the metal oxide porous body is 10 to 300 nm, preferably 10 to 200 nm. In order to make the average pore diameter 10 to 300 nm, organic inorganic particles made of a metal oxide such as titanium dioxide are used as a template using organic polymer particles that are dispersible in an aqueous medium and have a volume 50% average particle diameter of 10 to 300 nm. After forming the composite, the organic polymer particles may be removed by baking.

The pore characteristics of the porous material can be determined by nitrogen adsorption. From the nitrogen adsorption / desorption measurement of particles, the specific surface area can be calculated by BET (Brunauer-Emmett-Teller) method and the total pore volume can be calculated by BJH (Barrett-Joyner-Halenda) method. Furthermore, the porosity can be calculated from the total pore volume.
The porosity is not particularly limited, but is preferably 20 to 90%, more preferably 30 to 85%.

  The pores preferably have a cubic phase structure and are dispersed in a matrix mainly composed of a metal oxide. By taking a cubic phase structure, it can be expected that the strength is higher than that of a hexagonal phase structure or a random (disordered) structure.

1-3 Method for Producing Water-based Ink Pigment Hereinafter, a method for producing a water-based ink pigment comprising the above-described (A) organic-inorganic composite and / or (B) metal oxide porous material will be described.

  The (A) organic-inorganic composite of the present invention can be obtained by combining organic polymer particles and a metal oxide. (B) The metal oxide porous body is produced by removing organic polymer particles as a template from the (A) organic-inorganic composite.

Specifically, the following steps (a), (b) and (c) are included. Preferably, step (d) is further included.
Step (a): (a-1) or (a-2) is performed.
Step (a-1) Step of performing a sol-gel reaction of the metal oxide precursor in the presence of the above-mentioned water-insoluble organic polymer particles (a-2) The above-mentioned water-insoluble organic polymer particles and metal oxide nano A mixed solution containing particles and an aqueous medium is prepared.
Step (b): The mixed liquid obtained in the step (a) is dried to obtain an organic-inorganic composite.
Step (c): Organic polymer particles are removed from the organic-inorganic composite to prepare a metal oxide porous body.
Step (d): The organic-inorganic composite obtained in the step (b) and / or the metal oxide porous body obtained in the step (c) are wet-pulverized to a desired particle size, and then immersed in water. Dispersion is performed to obtain an aqueous dispersion.

Hereinafter, each process is demonstrated in order.
[Step (a)]
[Step (a-1)]
In the step (a-1), the water-insoluble organic polymer particles (X), the metal oxide precursor (Y), water and / or a solvent (Z) that dissolves a part or all of water in an arbitrary ratio. Are mixed to prepare a mixed composition, and a sol-gel reaction of the metal alkoxide and / or a partially hydrolyzed condensate thereof is performed. The mixed composition may contain a sol-gel reaction catalyst (W) for the purpose of promoting the hydrolysis / polycondensation reaction of the metal alkoxide.

  More specifically, the mixed composition is a solution in which the component (Y) or the component (Y) is dissolved in “water and / or a solvent (Z) that dissolves a part or all of water in an arbitrary ratio”. “Sol-gel reaction catalyst (W)”, and if necessary, water is added and stirred and mixed to perform the sol-gel reaction of component (Y), and water-insoluble while continuing this sol-gel reaction It is prepared by adding conductive organic polymer particles (X). The water-insoluble sharing machine polymer particles (X) can be added as an aqueous dispersion.

  Further, after adding an aqueous dispersion of water-insoluble organic polymer particles (X) to a solution in which component (Y) or component (Y) is dissolved in the solvent (Z) and stirring and mixing, catalyst (W), Furthermore, it can also prepare by adding water and stirring and mixing as needed.

[Metal oxide precursor (Y)]
Examples of the metal oxide precursor include a metal alkoxide and / or a partial hydrolysis condensate thereof, a metal halide, a metal acetate, a metal nitrate, and a metal sulfide.

The metal alkoxide in this invention points out what is represented by following formula (12).
(R ¹ ) xM (OR ² ) y (12)
In the formula, R ¹ is a hydrogen atom, an alkyl group (methyl group, ethyl group, propyl group, etc.), an aryl group (phenyl group, tolyl group, etc.), a carbon-carbon double bond-containing organic group (acryloyl group, methacryloyl group). And vinyl groups), halogen-containing groups (halogenated alkyl groups such as chloropropyl group and fluoromethyl group), and the like. R ² represents a lower alkyl group having 1 to 6 carbon atoms, preferably 1 to 4 carbon atoms. x and y are x + y = 4 and x represents an integer of 2 or less.

  Examples of M include titanium (Ti), zirconium (Zr), indium (In), zinc (Zn), selenium (Se), antimony (Sb), tin (Sn), yttrium (Y) rare earth metal, and the like. From the viewpoint of refractive index, titanium, zirconium, yttrium and the like are preferably used, and they may be used in combination.

  Metal alkoxides include titanium methoxide, titanium ethoxide, titanium-n-propoxide, titanium-i-propoxide, titanium-n-butoxide, titanium-t-butoxide, zirconium methoxide, zirconium ethoxide, zirconium-n. -Propoxide, zirconium-i-propoxide, zirconium-n-butoxide, zirconium-t-butoxide, indium methoxide, indium ethoxide, indium-n-propoxide, indium-i-propoxide, indium-n-butoxide , Indium-t-butoxide, zinc methoxide, zinc ethoxide, zinc-n-propoxide, zinc-i-propoxide, zinc-n-butoxide, zinc-t-butoxide, selenium methoxide, selenium ethoxide, selenium-n -Propoxide, selenium-i-propoxide, selenium-n-butoxide, selenium- -Butoxide, antimony methoxide, antimony ethoxide, antimony-n-propoxide, antimony-i-propoxide, antimony-n-butoxide, antimony-t-butoxide, tin methoxide, tin ethoxide, tin-n-propoxide, tin- i-propoxide, tin-n-butoxide, tin-t-butoxide, yttrium methoxide, yttrium ethoxide, yttrium-n-propoxide, yttrium-i-propoxide, yttrium-n-butoxide, yttrium-t-butoxide Is mentioned.

  A partially hydrolyzed condensate of metal alkoxide is a compound obtained by polycondensation of one or more of these metal alkoxides partially hydrolyzed using a sol-gel reaction catalyst (W). For example, a partially hydrolyzed polycondensation compound of a metal alkoxide.

  In the present invention, the partially hydrolyzed condensate of metal alkoxide is preferably an alkoxytitanium condensate or an alkoxyzirconium condensate condensate.

As a metal halide in this invention, what is represented by following formula (13) can be used.
(R ¹ ) xMZy (13)
In the formula, R ¹ represents a hydrogen atom, an alkyl group (such as a methyl group, an ethyl group, or a propyl group), an alkoxy group (such as a methoxy group, an ethoxy group, a propoxy group, or a butoxy group), an aryl group (such as a phenyl group or a tolyl group). ), A carbon-carbon double bond-containing organic group (acryloyl group, methacryloyl group, vinyl group and the like), a halogen-containing group (halogenated alkyl group such as chloropropyl group and fluoromethyl group) and the like. Z represents F, Cl, Br, or I. x and y represent an integer such that x + y ≦ 4 and x is 2 or less. Examples include titanium (Ti), zirconium (Zr), indium (In), zinc (Zn), selenium (Se), antimony (Sb), tin (Sn), and rare earth metals. From the viewpoint of refractive index, titanium, Zirconium, yttrium, etc. are preferably used, and they may be used in combination.

  Specific examples include titanium halide, zirconium halide, indium halide, zinc halide, selenium halide, antimony halide, yttrium halide, and hydrates thereof.

  Examples of the metal acetate include titanium acetate, zirconium acetate, indium acetate, zinc acetate, selenium acetate, antimony acetate, tin acetate, yttrium acetate, and hydrates thereof.

  Examples of the metal nitrate include titanium nitrate, zirconium nitrate, indium nitrate, zinc nitrate, selenium nitrate, antimony nitrate, tin nitrate, yttrium nitrate, and hydrates thereof.

  Examples of the metal sulfate include titanium sulfate, zirconium sulfate, indium sulfate, zinc sulfate, selenium sulfate, antimony sulfate, tin sulfate, yttrium sulfate, and hydrates thereof.

  Moreover, when it is desired to obtain a composite metal oxide such as barium titanate, a plurality of metal oxide precursors can be used.

[Solvent (Z) that dissolves water and / or a part or all of water in an arbitrary ratio]
In the composition of the present invention, the component (Z) is added for the purpose of further hydrolyzing the metal oxide precursor (Y).

  The component (Z) includes a solvent used when an aqueous dispersion is obtained using water-insoluble organic polymer particles, an aqueous dispersion, the component (Y), and a sol-gel reaction catalyst (W) (described later) ( Hereinafter, both of the solvents used when mixing the “component W”) may be included.

  The water is not particularly limited, and distilled water, ion exchange water, city water, industrial water, and the like can be used, but it is preferable to use distilled water or ion exchange water.

  The solvent for dissolving a part or all of water in an arbitrary ratio is not particularly limited as long as it is an organic solvent having an affinity for water and water-insoluble organic polymer particles can be dispersed. , Ethanol, propyl alcohol, isopropyl alcohol, acetone, acetonitrile, dimethyl sulfoxide, dimethylformamide, dimethylimidazolidinone, ethylene glycol, tetraethylene glycol, dimethylacetamide, N-methyl-2-pyrrolidone, tetrahydrofuran, dioxane, methyl ethyl ketone, cyclohexanone, Examples include cyclopentanone, 2-methoxyethanol (methyl cellosolve), 2-ethoxyethanol (ethyl cellosolve), and ethyl acetate. Among these, methanol, ethanol, propyl alcohol, isopropyl alcohol, acetonitrile, dimethyl sulfoxide, dimethylformamide, acetone, tetrahydrofuran, and dioxane are preferable because of their high affinity with water.

  When water is used, the amount of water to be added is usually in the range of, for example, 1 part by weight or more and 1000000 parts by weight or less, preferably 10 parts by weight, with respect to 100 parts by weight of the mixture of the component (Z) and the component (W). It is the range of not less than 10000 parts by weight.

  As a solvent for dissolving a part or all of water in an arbitrary ratio, the amount of the solvent to be added is usually 1 part by weight or more with respect to 100 parts by weight of the mixture of the component (Z) and the component (W). The range is 1 million parts by weight or less, preferably 10 parts by weight or more and 10,000 parts by weight or less.

  Moreover, the preferable reaction temperature at the time of hydrolysis polycondensation of metal alkoxides is 1 ° C. or more and 100 ° C. or less, more preferably 20 ° C. or more and 60 ° C. or less, and the reaction time is 10 minutes or more and 72 hours or less, More preferably, it is 1 hour or more and 24 hours or less.

[Sol-gel reaction catalyst (W)]
In the mixed composition used in the present invention, for the purpose of accelerating the reaction in the hydrolysis / polycondensation reaction of the metal alkoxide, it may contain a catalyst that can be a catalyst for the hydrolysis / polycondensation reaction as shown below.

  What is used as a catalyst for the hydrolysis and polycondensation reaction of metal alkoxides is “functional thin film production technology by the latest sol-gel method” (Satoru Hirashima, General Technology Center, page 29) and “sol-gel” It is a catalyst used in a general sol-gel reaction described in “Science of Law” (Sakuo Sakuo, Agne Jofu Co., Ltd., page 154).

  As the catalyst (W), acid catalyst, alkali catalyst, organotin compound, titanium tetraisopropoxide, diisopropoxytitanium bisacetylacetonate, zirconium tetrabutoxide, zirconium tetrakisacetylacetonate, aluminum triisopropoxide, aluminum tris Examples thereof include metal alkoxides such as ethyl acetonate and trimethoxyborane.

  Among these catalysts, acid catalysts and alkali catalysts are preferably used. Specifically, acid catalysts include hydrochloric acid, nitric acid, sulfuric acid, phosphoric acid, acetic acid, succinic acid, tartaric acid, toluenesulfonic acid and other inorganic and organic acids, and alkali catalysts include ammonium hydroxide, potassium hydroxide and sodium hydroxide. Alkali metal hydroxide, quaternary ammonium hydroxide such as tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrabutylammonium hydroxide, ammonia, triethylamine, tributylamine, morpholine, pyridine, piperidine, ethylenediamine, diethylenetriamine, ethanolamine , Amines such as diethanolamine and triethanolamine, aminosilanes such as 3-aminopropyltriethoxysilane and N (2-aminoethyl) -3-aminopropyltrimethoxysilane Etc., and the like.

  From the standpoint of reactivity, it is preferable to use an acid catalyst such as hydrochloric acid or nitric acid, where the reaction proceeds relatively gently. The amount of the catalyst used is preferably 0.001 mol or more and 0.05 mol or less, preferably 0.001 mol or more and 0.04 mol or less, more preferably 0.001 with respect to 1 mol of the metal alkoxide of the component (Y). The degree is not less than mol and not more than 0.03 mol.

  The mixed composition in the step (a-1) is used, for example, in the form of a sol-gel reactant obtained by performing a sol-gel reaction without removing the solvent (Z) in the presence of the catalyst (W). Can do.

[Step (a-2)]
In the step (a-2), an aqueous dispersion of metal oxide nanoparticles is prepared, and mixed with or reacted with the aqueous dispersion of water-insoluble organic polymer particles described above to prepare a liquid.

Specifically, the metal oxide nanoparticles selected in the present invention include titanium dioxide (TiO ₂ ), zirconium dioxide (ZrO ₂ ), yttria stabilized zirconium (YSZ), indium oxide (In ₂ O ₃ ), and zinc oxide. Examples include metal oxide nanoparticles containing one or more components of (ZnO), antimony oxide (Sb ₂ O ₅ ), tin oxide (SnO), and barium titanate (BaTiO ₃ ).

  More specifically, metal oxide nanoparticles containing two or more components are a structure in which one or more inorganic ultrafine particles are coated with one or more other inorganic materials (core-shell structure), and a crystal structure with two or more components. Such as to be formed.

  The particle diameter of the metal oxide nanoparticles is preferably 1 to 50 nm, more preferably 1 to 20 nm, and still more preferably 1 to 10 nm. Within this range, the properties as nanoparticles are maintained, and the regularity of the pores of the resulting porous body is good, which is preferable.

  In addition, the method for producing metal oxide nanoparticles can be roughly divided into a pulverization method and a synthesis method. Further, as synthesis methods, there are vapor phase methods such as evaporation condensation method and gas phase reaction method, liquid phase methods such as colloid method, homogeneous precipitation method, hydrothermal synthesis method and microemulsion method.

The method for producing the metal oxide nanoparticles used in the present invention is not particularly limited, but those produced by a synthesis method are preferable from the viewpoints of particle size, composition uniformity, impurities, and the like.
Each metal oxide nanoparticle is preferably dispersed in water or the like in a colloidal or slurry form. In order to keep the dispersion stable, a silane such as γ-glycidoxypropyltrimethoxysilane or methacryloyloxypropyltrimethoxysilane is used. The dispersion may be stabilized by adding a coupling agent, an organic acid such as a carboxylic acid, a polymer such as polyvinyl pyrrolidone or polyvinyl alcohol, or chemically bonding (surface modification) them to the surface of the fine particles.

  Examples of the aqueous medium in which the metal oxide nanoparticles are dispersed include water and / or a solvent that dissolves a part or all of water in an arbitrary ratio.

  The water is not particularly limited, and distilled water, ion exchange water, city water, industrial water, and the like can be used, but it is preferable to use distilled water or ion exchange water.

The solvent for dissolving a part or all of water in an arbitrary ratio is not particularly limited as long as it is an organic solvent having an affinity for water and water-insoluble organic polymer particles can be dispersed. , Ethanol, propyl alcohol, isopropyl alcohol, acetone, acetonitrile, dimethyl sulfoxide, dimethylformamide, dimethylimidazolidinone, ethylene glycol, tetraethylene glycol, dimethylacetamide, N-methyl-2-pyrrolidone, tetrahydrofuran, dioxane, methyl ethyl ketone, cyclohexanone, Examples include cyclopentanone, 2-methoxyethanol (methyl cellosolve), 2-ethoxyethanol (ethyl cellosolve), and ethyl acetate. Among these, methanol, ethanol, propyl alcohol, isopropyl alcohol, acetonitrile, dimethyl sulfoxide, dimethylformamide, acetone, tetrahydrofuran, and dioxane are preferable because of their high affinity with water.
The aqueous dispersion of metal oxide nanoparticles can be mixed with the water-insoluble organic polymer particles and used in the form of a mixed composition.

[Step (b)]
In the step (b), the reaction solution obtained in the step (a-1) or the mixed composition obtained in the step (a-2) is dried to obtain an organic-inorganic composite.

  As a method for producing composite particles, the reaction solution of the present invention, a mixed composition is heated and dried at a predetermined temperature to remove water or a solvent, and then the obtained solid is molded by a treatment such as pulverization or classification, or A method in which water or solvent is removed at low temperature after drying, such as freeze-drying, followed by heat drying at a predetermined temperature, and the resulting solid is formed by pulverization or classification, and further a composite of 10 μm or less There is a method of obtaining powder by spraying fine particles with a spray dryer (spray dryer) and volatilizing the solvent.

  When using the reaction solution obtained in the step (a-1), the sol-gel reaction is completed by heating and drying, and a metal oxide is obtained from the component (Y). A matrix is formed. The heating temperature for completing the sol-gel reaction is from room temperature to 300 ° C., more preferably from 80 ° C. to 200 ° C. The organic-inorganic composite has a structure in which the above-mentioned organic polymer particles are dispersed in this matrix.

The state in which the sol-gel reaction is completed is ideally a state in which all M-O-M bonds are formed, but some alkoxyl groups (M-OR ² ) and M-OH groups are partially formed. Although it remains, it includes a state in which it has shifted to a solid (gel) state.

  When the mixed composition obtained in the step (a-2) is used, the metal oxide nanoparticles are agglomerated and bonded to form a matrix mainly composed of the metal oxide by heating and drying. The heating temperature for promoting the aggregation and bonding of the metal oxide nanoparticles is from room temperature to 300 ° C., more preferably from 80 ° C. to 200 ° C. The organic-inorganic composite has a structure in which the above-mentioned organic polymer particles are dispersed in this matrix.

[Step (c)]
In the step (c), the organic polymer particles are removed from the organic-inorganic composite obtained in the step (b) to prepare a metal oxide porous body.

As a method for removing organic polymer particles, a method of decomposing and removing by firing, a method of decomposing and removing by irradiating with VUV light (vacuum ultraviolet light), far infrared rays, microwaves and plasma, and extraction and removing using a solvent or water. The method etc. are mentioned. When decomposing and removing by firing, the preferred temperature is 300 ° C to 2000 ° C, more preferably 400 ° C to 1000 ° C, more preferably 500 ° C to 800 ° C, when the firing temperature is too low, the organic polymer particles are not removed, while the high temperature If it is too large, the crystallite size increases and becomes larger than the pore diameter, so that the regularity of the structure may be lost, or the pores may collapse due to being close to the melting point of the metal oxide. Firing may be performed at a constant temperature, or may be gradually raised from room temperature. The firing time can be changed according to the temperature, but it is preferably performed in the range of 1 hour to 24 hours. Firing may be performed in air or in an inert gas such as nitrogen or argon. Moreover, you may carry out under reduced pressure or in a vacuum. In the case of irradiating and removing by VUV light, a VUV lamp, an excimer laser, or an excimer lamp can be used. May be used in combination with oxidation action of ozone (O ₃₎ generated at the time of irradiating the VUV light in air. As the microwave, any frequency of 2.45 GHz or 28 GHz may be used. The output of the microwave is not particularly limited, and a condition for removing the water-insoluble organic polymer particles is selected.

  When extraction is performed using a solvent or water, for example, ethylene glycol, tetraethylene glycol, isopropyl alcohol, acetone, acetonitrile, methanol, ethanol, cyclohexane, dimethyl sulfoxide, dimethylformamide, dimethylimidazolidinone, xylene, toluene , Chloroform, dichloromethane and the like can be used. The extraction operation may be performed under heating. Further, ultrasonic (US) treatment may be used in combination. In addition, after performing extraction operation, in order to remove the water | moisture content and solvent which remain | survive in a pore, it is preferable to perform heat processing under reduced pressure.

  The metal oxide porous particles of the present invention thus obtained have uniform pores, and the average pore diameter is 10 to 300 nm, preferably 10 to 200 nm. The metal oxide porous body of the present invention is a mesoporous structure and preferably has a cubic structure.

  Although the reason why a porous metal oxide having pores forming a cubic phase structure is obtained by using the water-insoluble organic polymer particles in the present invention as a template is not clear, it is presumed as follows: Is done.

  In the step (a) of the above-mentioned “metal oxide porous body production method”, when a plurality of water-insoluble organic polymer particles are added while performing the sol-gel reaction of the metal oxide precursor, The organic polymer particles repel each other by a predetermined surface charge, and are dispersed in a thermodynamically stable state with a predetermined distance, that is, a cubic structure such as Fm3m. Similarly, when a plurality of water-insoluble organic polymer particles are added to an aqueous dispersion of metal oxide nanoparticles, the plurality of water-insoluble organic polymer particles repel each other due to a predetermined surface charge, and heat with a predetermined distance is maintained. It is dispersed in a mechanically stable state, that is, a cubic structure such as Fm3m.

  Therefore, the pores of the metal oxide porous particles formed by removing the organic polymer particles dispersed in this way by calcination form a cubic phase.

[Step (d)]
In the step (d), the organic-inorganic composite obtained in the step (b) or the metal oxide porous material obtained in the step (c) is wet-pulverized to a desired particle size and dispersed in water. To obtain an aqueous dispersion.

  Grinding of bead mill, jet mill, ball mill, sand mill, attritor, roll mill, agitator mill, Henschel mixer, colloid mill, ultrasonic homogenizer, ang mill, etc. for the purpose of creating aqueous dispersions with pigments of desired particle size -A disperser can be used. Prior to filling the above pulverizer / disperser, pre-pulverization with a mortar may be performed. Moreover, you may use the mixer for premixes. For the next step, the aqueous dispersion can be used as it is, but in order to remove a minute amount of coarse particles, centrifugal separation, pressure filtration, vacuum filtration and the like can also be used.

  In order to stabilize the dispersion, addition of a surfactant is not indispensable, but for example, an anionic surfactant, a cationic surfactant, an amphoteric surfactant, a nonionic surfactant, etc. may coexist during the pulverization / dispersion treatment. good.

  Anionic surfactants include, for example, carboxylates, simple alkyl sulfonates, modified alkyl sulfonates, alkyl allyl sulfonates, alkyl sulfate esters, sulfated oils, sulfate esters, sulfated fatty acid monoglycerides, sulfated alkanol amides. Sulphated ethers, alkyl phosphate esters, alkyl benzene phosphonates, naphthalene sulfonic acid / formalin condensates.

  Examples of cationic surfactants include simple amine salts, modified amine salts, tetraalkyl quaternary ammonium salts, modified trialkyl quaternary ammonium salts, trialkyl benzyl quaternary ammonium salts, and modified trialkyl benzyl quaternary salts. Examples include quaternary ammonium salts, alkyl pyridinium salts, modified alkyl pyridinium salts, alkyl quinolinium salts, alkyl phosphonium salts, and alkyl sulfonium salts.

  Examples of amphoteric surfactants include betaine, sulfobetaine, sulfate betaine and the like.

  Nonionic surfactants include, for example, fatty acid monoglycerin ester, fatty acid polyglycol ester, fatty acid sorbitan ester, fatty acid sucrose ester, fatty acid alkanol amide, fatty acid polyethylene glycol glycol condensate, fatty acid amide polyethylene glycol condensate, Examples include fatty acid alcohol / polyethylene / glycol condensate, fatty acid amine / polyethylene / glycol condensate, fatty acid mercaptan / polyethylene / glycol condensate, alkyl / phenol / polyethylene / glycol condensate, and polypropylene / glycol / polyethylene / glycol condensate. .

These surfactants can be used alone or in combination of two or more.
In order to suppress foaming during pulverization / dispersion, an antifoaming agent may be added. Examples of antifoaming agents include silicones, polyethers, and alcohols. These antifoaming agents can be used alone or in combination of two or more.

  The particle diameter of the pigment after pulverization / dispersion is preferably 0.1 μm to 5 μm, more preferably 0.1 μm to 5 μm, when measured with a dynamic light scattering nanotrack particle size analyzer “Microtrac UPA-EX150 (Nikkiso Co., Ltd.)”. Is 0.2 μm to 1 μm.

2. Water-based ink composition The water-based ink composition of the present invention contains the water-based ink pigment and water. Further, it may contain a water-soluble organic solvent, a lubricant, a polymer dispersant, a surfactant, other colorants, and other various additives.

  The addition amount of the pigment for water-based ink according to the present invention is preferably in the range of about 1 to 40% by mass, more preferably 3 to 30% by mass with respect to the whole ink. In the present invention, even with such a high pigment concentration, the dispersibility of the pigment particles and the clogging reliability are excellent, and an image with high hiding power can be obtained by increasing the pigment concentration in the ink. It is done.

Examples of the solvent of the water-based ink composition according to the present invention include water or a mixed solvent of water and a water-soluble organic solvent. As the water, pure water such as ion exchange water, ultrafiltration water, reverse osmosis water, distilled water, or ultrapure water can be used. In addition, the use of water sterilized by ultraviolet irradiation or addition of hydrogen peroxide is preferable because generation of mold and bacteria can be prevented when the ink composition is stored for a long period of time. The water-soluble organic solvent is preferably a low-boiling organic solvent, and examples thereof include methanol, ethanol, n-propyl alcohol, iso-propyl alcohol, n-butanol, sec-butanol, tert-butanol, iso- Examples include butanol and n-pentanol. A monohydric alcohol is particularly preferable.
The low boiling point organic solvent has an effect of shortening the drying time of the ink. The amount of the low-boiling organic solvent added is preferably from 0.5 to 10% by mass, more preferably from 1.5 to 6% by mass, based on the aqueous ink composition.

  The aqueous ink composition according to the present invention preferably further comprises a wetting agent such as a high boiling point organic solvent. Preferred examples of the wetting agent include ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, polypropylene glycol, propylene glycol, butylene glycol, 1,2,6-hexanetriol, thioglycol, hexylene glycol, glycerin, and trimethylolethane. Polyhydric alcohols such as trimethylolpropane, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, triethylene glycol Multivalent such as ethylene glycol monobutyl ether Alkyl ethers of alcohols, urea, 2-pyrrolidone, N- methyl-2-pyrrolidone, 1,3-dimethyl-2-like imidazolidinone.

  The addition amount of these wetting agents is preferably 0.5 to 40% by mass, more preferably 2 to 20% by mass of the aqueous ink composition.

  The aqueous ink composition according to the present invention preferably contains a polymer dispersant. Examples of the polymer dispersant include natural polymers. Specifically, proteins such as glue, gelatin, casein, albumin, natural rubbers such as gum arabic and tragacanth, glucosides such as saponin, alginic acid and propylene glycol alginate, triethanolamine alginate, alginic acid derivatives such as ammonium alginate, etc. , Cellulose derivatives such as methylcellulose, carboxymethylcellulose, hydroxyethylcellulose, and ethylhydroxycellulose. Furthermore, preferred examples of the polymer dispersant include synthetic polymers such as polyvinyl alcohols, polyvinyl pyrrolidones, polyacrylic acid, acrylic acid / acrylonitrile copolymers, potassium acrylate / acrylonitrile copolymers, vinyl acetate / acrylic. Acid ester copolymers, acrylic resins such as acrylic acid / acrylic ester copolymers, styrene / acrylic acid copolymers, styrene / methacrylic acid copolymers, styrene / methacrylic acid / acrylic acid ester copolymers, Styrene-acrylic resin such as styrene / α-methylstyrene / acrylic acid copolymer, styrene / α-methylstyrene / acrylic acid / acrylic acid ester copolymer, styrene / maleic acid copolymer, styrene / maleic anhydride copolymer Polymer, vinyl naphthalene / acrylic acid copolymer , Vinyl naphthalene / maleic acid copolymer, and vinyl acetate / ethylene copolymer, vinyl acetate / fatty acid vinyl / ethylene copolymer, vinyl acetate / maleic acid ester copolymer, vinyl acetate / crotonic acid copolymer, Examples thereof include vinyl acetate copolymers such as vinyl acetate / acrylic acid copolymers and salts thereof. Among these, a copolymer of a monomer having a hydrophobic group and a monomer having a hydrophilic group, and a polymer comprising a monomer having both a hydrophobic group and a hydrophilic group in the molecular structure, such as styrene / acrylic An acid copolymer, a styrene / methacrylic acid copolymer, and the like are preferable.

  The ink composition according to the present invention may further contain a surfactant. Examples of the surfactant include the surfactants exemplified in the step (d). These can be used alone or in combination of two or more. In addition, you may add a pH adjuster, antiseptic | preservative, antifungal agent, antioxidant, etc. as needed.

  In the present invention, a light-colored ink can be obtained by adding an appropriate amount of a pigment and / or dye other than the pigment for aqueous ink according to the present invention.

  The ink composition according to the present invention can be produced by dispersing and mixing each of the above components by an appropriate method. After preparing a solution to which each ink component has been added and stirring sufficiently, it is possible to obtain a desired ink composition by performing filtration in order to remove coarse particles and foreign matters that cause clogging. For example, it can manufacture by adding an additive etc. suitably as needed to the aqueous dispersion obtained at the said process (d).

  Applications of the aqueous ink composition of the present invention include, for example, inkjet printing, offset printing, gravure printing, and the like, and are particularly suitable for printing with an inkjet printer.

3. Images and printed matter Images and printed matter can be obtained by printing on a substrate (substrate) using the aqueous ink composition of the present invention. Examples of the base material include paper, textiles, plastic, glass, ceramics, and metal.

The water-based ink composition of the present invention can well hide the base. Furthermore, when the water-based ink composition of the present invention is a white ink, images and printed matter with high whiteness can be obtained. In addition, after printing with the aqueous ink composition of the present invention, good color developability of the color ink can be obtained by printing using various color inks.
Also, images and prints obtained from an aqueous ink composition containing an aqueous pigment obtained using titanium dioxide whose surface is coated with zirconium dioxide have good light resistance.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the scope of the present invention is not limited to these examples.

<Water-insoluble organic polymer particles-1>
<Synthesis of polyolefin end-branched copolymer>
Number average molecular weight (Mn), weight average molecular weight (Mw), and molecular weight distribution (Mw / Mn) were measured by GPC using the method described in the text. Moreover, the peak top temperature obtained by measuring using DSC was employ | adopted for melting | fusing point (Tm). In addition, although melting | fusing point of a polyalkylene glycol part is also confirmed by measurement conditions, here, unless there is particular notice, it refers to melting | fusing point of a polyolefin part. ¹ H-NMR was measured at 120 ° C. after completely dissolving the polymer in deuterated 1,1,2,2-tetrachloroethane serving as a lock solvent and a solvent in a measurement sample tube. . The chemical shift was determined by setting the peak of deuterated 1,1,2,2-tetrachloroethane to 5.92 ppm and determining the chemical shift value of other peaks. As for the particle diameter of the particles in the dispersion, a 50% volume average particle diameter was measured with Microtrac UPA (manufactured by HONEYWELL). The shape of the particles in the dispersion was observed by diluting the sample 200 to 500 times, negatively staining with phosphotungstic acid, and then using a transmission electron microscope (TEM / H-7650 manufactured by Hitachi, Ltd.) under the condition of 100 kV. I did it.

(Synthesis of polyolefin end-branched copolymer (T))
A terminal epoxy group-containing ethylene polymer (E) was synthesized according to the following procedure (for example, see Synthesis Example 2 of JP-A-2006-131870).

A stainless steel autoclave with an internal volume of 2000 ml sufficiently purged with nitrogen was charged with 1000 ml of heptane at room temperature, and the temperature was raised to 150 ° C. Subsequently, 30 kg / cm ² G was pressurized with ethylene in the autoclave to maintain the temperature. A hexane solution (1.00 mmol / ml of aluminum atom equivalent) of MMAO (manufactured by Tosoh Finechem) was injected with 0.5 ml (0.5 mmol), and then a toluene solution (0.0002 mmol / ml) of a compound of the following formula: 0.5 ml (0.0001 mmol) was injected to initiate the polymerization. After carrying out the polymerization at 150 ° C. for 30 minutes in an ethylene gas atmosphere, the polymerization was stopped by press-fitting a small amount of methanol. The obtained polymer solution was added to 3 liters of methanol containing a small amount of hydrochloric acid to precipitate a polymer. After washing with methanol, it was dried under reduced pressure at 80 ° C. for 10 hours to obtain a single-end double bond-containing ethylene polymer (P).

In a 500 ml separable flask, 100 g of the ethylene polymer (P) containing one end double bond (Mn850, vinyl group 108 mmol), 300 g of toluene, 0.85 g (2.6 mmol) of Na ₂ WO ₄ , CH ₃ (nC ₈ H ₁₇ ) ₃ NHSO ₄ (0.60 g, 1.3 mmol) and phosphoric acid (0.11 g, 1.3 mmol) were charged, and the mixture was heated to reflux with stirring for 30 minutes to completely melt the polymer. After the internal temperature was set to 90 ° C., 37 g (326 mmol) of 30% hydrogen peroxide solution was added dropwise over 3 hours, and the mixture was stirred at an internal temperature of 90 to 92 ° C. for 3 hours. Thereafter, 34.4 g (54.4 mmol) of a 25% aqueous sodium thiosulfate solution was added while maintaining the temperature at 90 ° C., and the mixture was stirred for 30 minutes. The peroxide in the reaction system was completely decomposed with the peroxide test paper. It was confirmed. Subsequently, 200 g of dioxane was added at an internal temperature of 90 ° C. to crystallize the product, and the solid was collected by filtration and washed with dioxane. The obtained solid was stirred in a 50% aqueous methanol solution at room temperature, and the solid was collected by filtration and washed with methanol. Further, the solid was stirred in 400 g of methanol, collected by filtration and washed with methanol. By drying under reduced pressure of room temperature and 1-2 hPa, 96.3 g of white solid of terminal epoxy group-containing ethylene polymer (E) was obtained (yield 99%, polyolefin conversion rate 100%).

The obtained terminal epoxy group-containing ethylene polymer (E) was Mw = 2058, Mn = 1118, Mw / Mn = 1.84 (GPC). (Terminal epoxy group content: 90 mol%)
¹ H-NMR: δ (C2D2Cl4) 0.88 (t, 3H, J = 6.92 Hz), 1.18-1.66 (m), 2.38 (dd, 1H, J = 2.64, 5.28 Hz), 2.66 (dd, 1H, J = 4.29, 5.28 Hz), 2.80-2.87 (m, 1H)
Melting point (Tm) 121 ℃
Mw = 2058, Mn = 1118, Mw / Mn = 1.84 (GPC)

A 1000 mL flask was charged with 84 parts by weight of a terminal epoxy group-containing ethylene polymer (E), 39.4 parts by weight of diethanolamine, and 150 parts by weight of toluene, and stirred at 150 ° C. for 4 hours. Thereafter, acetone was added while cooling to precipitate the reaction product, and the solid was collected by filtration. The obtained solid was stirred and washed once with an aqueous acetone solution and further three times with acetone, and then the solid was collected by filtration. Thereafter, the polymer (I) (Mn = 1223, A: group formed by polymerization of ethylene (Mn = 1075) in the general formula (9) (Mn = 1075), R ¹ = R ² = by drying under reduced pressure at room temperature. A hydrogen atom, ^one of Y ¹ and Y ² was a hydroxyl group, and the other was a bis (2-hydroxyethyl) amino group).
¹ H-NMR: δ (C2D2Cl4) 0.88 (t, 3H, J = 6.6 Hz), 0.95-1.92 (m), 2.38-2.85 (m, 6H), 3.54-3.71 (m, 5H)
Melting point (Tm) 121 ℃

  A 500 mL flask equipped with a nitrogen introduction tube, a thermometer, a cooling tube, and a stirrer is charged with 20.0 parts by weight of polymer (I) and 100 parts by weight of toluene and heated in an oil bath at 125 ° C. while stirring to obtain a solid. Was completely dissolved. After cooling to 90 ° C., 0.323 parts by weight of 85% KOH previously dissolved in 5.0 parts by weight of water was added to the flask and mixed for 2 hours under reflux conditions. Thereafter, water and toluene were distilled off while gradually raising the temperature in the flask to 120 ° C. Further, while supplying a slight amount of nitrogen to the flask, the pressure in the flask was reduced, and the internal temperature was raised to 150 ° C. and maintained for 4 hours to further distill off water and toluene in the flask. After cooling to room temperature, the solidified solid in the flask was crushed and taken out.

A stainless steel 1.5 L pressure reactor equipped with a heating device, a stirring device, a thermometer, a pressure gauge, and a safety valve was charged with 18.0 parts by weight of the obtained solid and 200 parts by weight of dehydrated toluene. After substituting with nitrogen, the temperature was raised to 130 ° C. with stirring. After 30 minutes, 9.0 parts by weight of ethylene oxide was added, and the mixture was further maintained at 130 ° C. for 5 hours, and then cooled to room temperature to obtain a reaction product. A solvent is removed from the obtained reaction product by drying, and a polyolefin-based terminally branched copolymer (T) (Mn = 1835, in formula (1), A: a group formed by polymerization of ethylene (Mn = 1075)). , R ¹ = R ² = hydrogen atom, ^one of X ¹ and X ² is a group represented by the general formula (6) (X ¹¹ = polyethylene glycol group), and the other is a group represented by the general formula (5) (Q ¹ = Q ² = ethylene group, X ⁹ = X ¹⁰ = polyethylene glycol group)).
¹ H-NMR: δ (C2D2Cl4) 0.88 (3H, t, J = 6.8 Hz), 1.06-1.50 (m), 2.80-3.20 (m), 3.33-3.72 (m)
Melting point (Tm) -16 ° C (polyethylene glycol), 116 ° C

<Preparation Example of Polyolefin-Based Branched Copolymer Aqueous Dispersion>
(Preparation of 10% by weight polyolefin end-branched copolymer (T) aqueous dispersion)
10 parts by weight of the polyolefin end branched copolymer (T) obtained in the above synthesis example and 40 parts by weight of distilled water were charged into a 100 ml autoclave, heated and stirred at 140 ° C. and 800 rpm for 30 minutes, The mixture was cooled to room temperature while maintaining stirring. The obtained dispersion had a volume 50% average particle size of 18 nm. (Volume 10% average particle diameter 14 nm, volume 90% average particle diameter 22 nm) The particle diameter measured from the transmission electron microscope observation result of the obtained dispersion was 15 to 30 nm. Further, 75 parts by weight of distilled water is added to 75 parts by weight of this (T) aqueous dispersion (solid content: 20% by weight) to obtain a 10% by weight polyolefin-based terminally branched copolymer (T) aqueous dispersion. It was.

<Water-insoluble organic polymer particles-2>
As an aqueous dispersion (acrylic emulsion) of a polymethacrylic acid ester copolymer, PAN-6 manufactured by Mitsui Chemicals (dynamic light scattering nanotrack particle size analyzer “Microtrack UPA-EX150 (made by Nikkiso Co., Ltd.)” 50% volume average particle diameter: 90-130 nm, concentration: 45.89% by weight) was used.

<Preparation of metal oxide nanoparticle dispersion>
<Synthesis of titanium dioxide nanoparticles and preparation of dispersion>
7.5 ml (equivalent to 0.036 mol of Ti) of titanium oxychloride / hydrochloric acid aqueous solution (Fluka reagent hydrochloric acid: 38 to 42%, Ti: about 15%) was dissolved in 1000 ml of ion-exchanged water. Stir at a temperature of 70 ° C. After 5 hours, a bluish titanium dioxide colloidal aqueous solution was obtained.

  The pH of the aqueous colloidal solution was adjusted to around 2.5 by ion dialysis to obtain an aqueous dispersion of titanium dioxide having a solid concentration of 10% by weight. A part of the obtained aqueous dispersion was dropped onto a mesh to prepare an electron microscope observation sample, which was observed and confirmed to be a titanium dioxide crystal having an average particle diameter of 3 nm.

<Synthesis of zirconium dioxide-coated titanium dioxide ultrafine particles and preparation of aqueous dispersion>
Similar to the synthesis of titanium dioxide nanoparticles, a bluish titanium dioxide colloidal solution was obtained.
To the colloidal solution, 6.4 parts by weight of zirconium oxychloride octahydrate (Zr: equivalent to 0.02 mol) was added, and the temperature of the reaction solution was kept at 70 ° C. and stirred for 2 hours. As a result, a bluish white slurry-like sol solution was obtained. The pH of the aqueous colloidal solution was adjusted to around 2.5 by ion dialysis to obtain an aqueous dispersion of zirconium dioxide-coated titanium dioxide having a solid content concentration of 10% by weight. A part of the obtained aqueous dispersion was dropped onto a mesh to prepare an electron microscope observation sample, which was observed and confirmed to be a titanium dioxide crystal having an average particle diameter of 3 nm. An amorphous coating layer was observed around a titanium dioxide crystal having a titanium dioxide crystal lattice spacing with an average particle diameter of 3 nm. The amorphous layer-covered titanium dioxide was found to be composed of Ti and Zr at a molar ratio of 1: 1.

  Further, X-ray diffraction spectrum measurement confirmed that amorphous zirconium dioxide was superimposed on titanium dioxide.

Example 1
(Preparation of Polyolefin-based Branched Copolymer / TTIP Dehydration Condensate Solution)
After dropping 1.32 parts by weight of an aqueous hydrochloric acid catalyst solution (37%) into 2.0 parts by weight of titanium tetraisopropoxide (TTIP), the mixture was stirred at room temperature for 10 minutes to obtain a dehydrated condensate of TTIP.
To the obtained dehydrated condensate of TTIP, 2.4 parts by weight of an aqueous dispersion (solid content: 10% by weight) of a polyolefin end-branched copolymer (T) was further added dropwise and stirred at room temperature. A branched copolymer / TTIP dehydration condensate solution was prepared. (Polyolefin end-branched copolymer / TiO2 = 30/70 weight ratio)

(Formation of polyolefin end-branched copolymer / titanium dioxide composite particles)
The composition was poured into a spray dryer, pressurized (0.2 MPa) at a nozzle outlet temperature of 190 ° C., and sprayed to obtain polyolefin-based terminally branched copolymer / titanium dioxide composite fine particles.

(Formation of titanium dioxide porous particles)
By heating the obtained polyolefin end-branched copolymer / titanium dioxide composite particles from room temperature to 600 ° C. at a rate of 5 ° C. per minute using an electric furnace, and further firing at 600 ° C. for 2 hours. The polyolefin end-branched copolymer was removed to obtain porous titanium dioxide particles.

(Preparation of aqueous dispersion)
The polyolefin-based terminally branched copolymer / titanium dioxide composite fine particles and titanium dioxide porous particles were pulverized and dispersed in water using a wet type bead mill. Grinding while confirming the particle size with a dynamic light scattering nanotrack particle size analyzer “Microtrac UPA-EX150 (Nikkiso Co., Ltd.)”, and when the particle size distribution becomes 0.2 to 1 μm, dispersion is performed. It was collected.

(Example 2)
(Preparation of polymethacrylate copolymer / TTIP dehydration condensate solution)
After dropping 1.32 parts by weight of an aqueous hydrochloric acid catalyst solution (37%) into 2.0 parts by weight of titanium tetraisopropoxide (TTIP), the mixture was stirred at room temperature for 10 minutes to obtain a dehydrated condensate of TTIP.
To the obtained dehydrated condensate of TTIP, 0.52 part by weight (solid content: 0.24 part by weight) of polymethacrylic acid ester copolymer (acrylic emulsion) PAN-6, and further water 1.9 The solution was diluted with parts by weight and stirred at room temperature to prepare a polymethacrylic acid ester copolymer / TTIP dehydrated condensate solution. (Polymethacrylate copolymer / TiO2 = 30/70 weight ratio)

(Formation of polymethacrylic acid ester copolymer / titanium dioxide composite particles)
The composition was poured into a spray dryer, pressurized (0.2 MPa) at a nozzle outlet temperature of 190 ° C., and sprayed to obtain polymethacrylate copolymer / titanium dioxide composite particles.

(Formation of titanium dioxide porous particles)
By heating the obtained polymethacrylic ester copolymer / titanium dioxide composite particles from room temperature to 600 ° C. at a rate of 5 ° C. per minute using an electric furnace, and further firing at 600 ° C. for 2 hours. The polymethacrylic acid ester copolymer was removed to obtain titanium dioxide porous particles.

(Preparation of aqueous dispersion)
The polymethacrylic acid ester copolymer / titanium dioxide composite fine particles and titanium dioxide porous particles were pulverized and dispersed in water using a wet type bead mill. Crushing was performed while confirming the particle size, and the dispersion was collected when the particle size distribution reached 0.2 to 1 μm.

(Example 3)
(Preparation of polyolefin end-branched copolymer / titanium dioxide nanoparticle mixture)
While stirring the titanium dioxide nanoparticle dispersion liquid (solid content concentration 10% by weight) to 50 parts by weight (solid content 5.0 parts by weight), an aqueous dispersion (solid) of the polyolefin-based terminally branched copolymer (T) 10 wt%) was diluted with 27 parts by weight (solid content: 2.7 parts by weight) and further with 77.0 parts by weight of water to prepare a polyolefin end-branched copolymer / TiO 2 nanoparticle mixture.

(Polyolefin end-branched copolymer / TiO2 = 35/65 weight ratio)
(Formation of polyolefin end-branched copolymer / titanium dioxide composite particles)
The composition was poured into a spray dryer, pressurized (0.2 MPa) at a nozzle outlet temperature of 190 ° C., and sprayed to obtain a polyolefin end-branched copolymer / titanium dioxide composite particle.

(Formation of titanium dioxide porous particles)
By heating the obtained polyolefin end-branched copolymer / titanium dioxide composite particles from room temperature to 600 ° C. at a rate of 5 ° C. per minute using an electric furnace, and further firing at 600 ° C. for 2 hours. The polyolefin end-branched copolymer was removed to obtain porous titanium dioxide particles.

(Preparation of aqueous dispersion)
The polyolefin-based terminally branched copolymer / titanium dioxide composite fine particles and titanium dioxide porous particles were pulverized and dispersed in water using a wet type bead mill. Crushing was performed while confirming the particle size, and the dispersion was collected when the particle size distribution reached 0.2 to 1 μm.

Example 4
(Preparation of polymethacrylate copolymer / titanium dioxide nanoparticle mixture)
While stirring the titanium dioxide nanoparticle dispersion liquid (solid content concentration: 10% by weight) to 50 parts by weight (solid content: 5.0 parts by weight), polymethacrylic acid ester copolymer (acrylic emulsion) PAN-6 was added. It was diluted with 5.87 parts by weight (solid content: 2.7 parts by weight) and further with 96.3 parts by weight of water to prepare a polymethacrylic acid ester copolymer / TiO 2 nanoparticle mixed solution. (Polymethacrylate copolymer / TiO2 = 35/65 weight ratio)

(Formation of polymethacrylic acid ester copolymer / titanium dioxide composite particles)
The composition was poured into a spray dryer, pressurized (0.2 MPa) at a nozzle outlet temperature of 190 ° C., and sprayed to obtain polymethacrylate copolymer / titanium dioxide composite particles.

(Formation of titanium dioxide porous particles)
By heating the obtained polymethacrylic ester copolymer / titanium dioxide composite particles from room temperature to 600 ° C. at a rate of 5 ° C. per minute using an electric furnace, and further firing at 600 ° C. for 2 hours. The polymethacrylic acid ester copolymer was removed to obtain titanium dioxide porous particles.

(Preparation of aqueous dispersion)
The polymethacrylic acid ester copolymer / titanium dioxide composite fine particles and titanium dioxide porous particles were pulverized and dispersed in water using a wet type bead mill. Crushing was performed while confirming the particle size, and the dispersion was collected when the particle size distribution reached 0.2 to 1 μm.

(Example 5)
(Preparation of Polyolefin-based Branched Copolymer / Zirconium Dioxide-Coated Titanium Dioxide Nanoparticle Mixture)
While stirring the above-mentioned zirconium dioxide-coated titanium dioxide nanoparticle dispersion (solid content concentration: 10% by weight) to 67.2 parts by weight (solid content: 6.72 parts by weight), the polyolefin end-branched copolymer (T) Aqueous dispersion (solid content: 10% by weight) was diluted with 32.8 parts by weight (solid content: 3.28 parts by weight) and further with 77.0 parts by weight of water to obtain a polyolefin-based terminally branched copolymer / TiO2 nanoparticle. A mixture was prepared. (Polyolefin end-branched copolymer / TiO2 = 32.8 / 67.2 weight ratio)

(Formation of polyolefin end-branched copolymer / titanium dioxide composite particles)
The composition was poured into a spray dryer, pressurized (0.2 MPa) at a nozzle outlet temperature of 190 ° C., and sprayed to obtain a polyolefin-based terminally branched copolymer / titanium dioxide-based composite particle.

(Formation of titanium dioxide-based porous particles)
The resulting polyolefin end-branched copolymer / titanium dioxide composite particles are heated from room temperature to 600 ° C. at a rate of 5 ° C. per minute using an electric furnace, and further calcined at 600 ° C. for 2 hours. By removing the polyolefin terminal branched copolymer, titanium dioxide porous particles were obtained.

(Preparation of aqueous dispersion)
The polyolefin terminal branched copolymer / titanium dioxide composite fine particles and titanium dioxide porous particles were pulverized and dispersed in water using a wet type bead mill. Crushing was performed while confirming the particle size, and the dispersion was collected when the particle size distribution reached 0.2 to 1 μm.

(Example 6)
(Preparation of polymethacrylic acid ester copolymer / zirconium dioxide-coated titanium dioxide nanoparticle mixture)
Aqueous dispersion of polymethacrylic acid ester copolymer while stirring the above-mentioned zirconium dioxide-coated titanium dioxide nanoparticle dispersion (solid content concentration 10% by weight) to 67.2 parts by weight (solid content 6.72 parts by weight). (Solid content: 10% by weight) is diluted with 32.8 parts by weight (solid content: 3.28 parts by weight) and further with 77.0 parts by weight of water, and then a polymethacrylate copolymer / zirconium dioxide-coated titanium dioxide nanoparticles. A mixture was prepared. (Polymethacrylate copolymer / TiO2 system = 32.8 / 67.2 weight ratio)

(Formation of polymethacrylate copolymer / titanium dioxide composite particles)
This composition was poured into a spray dryer, pressurized (0.2 MPa) at a nozzle outlet temperature of 190 ° C., and sprayed to obtain a polymethacrylate copolymer / titanium dioxide composite particle.

(Formation of titanium dioxide-based porous particles)
The obtained polymethacrylic acid ester copolymer / titanium dioxide composite particles are heated from room temperature to 600 ° C. at a rate of 5 ° C. per minute using an electric furnace, and further fired at 600 ° C. for 2 hours. By removing the polymethacrylate copolymer, titanium dioxide-based porous particles were obtained.

(Preparation of aqueous dispersion)
The polymethacrylic acid ester copolymer / titanium dioxide composite fine particles and titanium dioxide porous particles were pulverized and dispersed in water using a wet type bead mill. Crushing was performed while confirming the particle size, and the dispersion was collected when the particle size distribution reached 0.2 to 1 μm.

(Example 7)
(Preparation of polyolefin-based terminally branched copolymer / YSZ nanoparticle mixture)
While stirring 28.4 parts by weight (solid content 2.84 parts by weight) of YSZ nanoparticle dispersion liquid (Nissan Chemical Co., Ltd. ultrafine zirconia sol # 1, particle size 5 nm, solid content concentration 10% by weight) The aqueous dispersion of the branched copolymer (T) (solid content: 10% by weight) was diluted with 11.6 parts by weight (solid content: 1.16 parts by weight) and further with 40.0 parts by weight of water, and then the polyolefin end A branched copolymer / YSZ nanoparticle mixed solution was prepared. (Polyolefin end-branched copolymer / YSZ = 29/71 weight ratio)

(Formation of polyolefin-based terminally branched copolymer / YSZ composite particles)
The composition was poured into a spray dryer, pressurized (0.2 MPa) at a nozzle outlet temperature of 190 ° C., and sprayed to obtain composite fine particles of polyolefin-based terminally branched copolymer / YSZ.

(Formation of YSZ porous particles)
Polyolefin end-branched copolymer / YSZ composite particles obtained were heated at a rate of 5 ° C. per minute from room temperature to 600 ° C. using an electric furnace, and further baked at 600 ° C. for 2 hours. The system branched end copolymer was removed to obtain YSZ porous particles.

(Preparation of aqueous dispersion)
The polyolefin-based terminally branched copolymer / YSZ composite fine particles and YSZ porous particles were pulverized and dispersed in water using a wet type bead mill. Crushing was performed while confirming the particle size, and the dispersion was collected when the particle size distribution reached 0.2 to 1 μm.

(Example 8)
(Preparation of polymethacrylic acid ester copolymer / Ba (CH ₃ COO) ₂ / TTIP dehydration condensate solution)
To 20.8 parts by weight of acetic acid, 8.09 parts by weight of barium acetate was added and stirred at 60 ° C. to dissolve.
Further, 9.1 parts by weight of titanium tetraisopropoxide (TTIP) was added and stirred at room temperature, and 10.24 g (solid content: 4.7 g) of polymethacrylic acid ester copolymer (acrylic emulsion) PAN-6. Further, it was diluted with 83.76 parts by weight of water to prepare a polymethacrylic acid ester copolymer / Ba (CH ₃ COO) ₂ / TTIP dehydration condensate solution. (Polymethacrylate copolymer / BaTiO ₃ = 30/70 weight ratio)

(Formation of polymethacrylate copolymer / barium titanate composite particles)
The composition was poured into a spray dryer, pressurized (0.2 MPa) at a nozzle outlet temperature of 190 ° C., and sprayed to obtain composite fine particles of polymethacrylate copolymer / barium titanate.

(Formation of barium titanate porous particles)
The obtained polymethacrylic acid ester copolymer / barium titanate composite particles are heated from room temperature to 600 ° C. at a rate of 5 ° C. per minute using an electric furnace, and further calcined at 600 ° C. for 2 hours. By removing the polymethacrylate copolymer, barium titanate porous particles were obtained.

(Preparation of aqueous dispersion)
The polymethacrylic acid ester copolymer / barium titanate composite fine particles and the barium titanate porous particles were pulverized and dispersed in water using a wet type bead mill. Crushing was performed while confirming the particle size, and the dispersion was collected when the particle size distribution reached 0.2 to 1 μm.

(Comparative Example 1)
(Preparation of TTIP dehydration condensate solution)
After dropping 1.32 parts by weight of an aqueous hydrochloric acid catalyst solution (37%) into 2.0 parts by weight of titanium tetraisopropoxide (TTIP), the mixture was stirred at room temperature for 10 minutes to obtain a dehydrated condensate of TTIP.

(Formation of titanium dioxide particles)
The dehydrated condensate was poured into a spray dryer, pressurized (0.2 MPa) at a nozzle outlet temperature of 190 ° C., and sprayed to obtain titanium dioxide particles.

(Formation of titanium dioxide particles)
The obtained titanium dioxide particles were heated and fired at a rate of 5 ° C./min from room temperature to 600 ° C. using an electric furnace.

(Preparation of aqueous dispersion)
The titanium dioxide particles before and after the firing treatment were pulverized and dispersed in water using a wet type bead mill. Crushing was performed while confirming the particle size, and the dispersion was collected when the particle size distribution reached 0.2 to 1 μm.

(Comparative Example 2)
(Formation of titanium dioxide particles)
The above-mentioned titanium dioxide nanoparticle dispersion (solid content concentration 10% by weight) was poured into a spray dryer device, pressurized (0.2 MPa) at a nozzle outlet temperature of 190 ° C., and sprayed to obtain titanium dioxide particles. Furthermore, using an electric furnace, the temperature was raised from room temperature to 600 ° C. at a rate of 5 ° C. per minute, followed by firing treatment.

(Preparation of aqueous dispersion)
The titanium dioxide particles before and after the firing treatment were pulverized and dispersed in water using a wet type bead mill. Crushing was performed while confirming the particle size, and the dispersion was collected when the particle size distribution reached 0.2 to 1 μm.

(Comparative Example 3)
(Formation of YSZ particles)
A YSZ nanoparticle dispersion (Nissan Chemical Co., Ltd. ultrafine zirconia sol # 1, particle size 5 nm, solid content concentration 10% by weight) was poured into a spray dryer, pressurized at a nozzle outlet temperature of 190 ° C. (0.2 MPa), and sprayed. As a result, YSZ particles were obtained. Furthermore, using an electric furnace, the temperature was raised from room temperature to 600 ° C. at a rate of 5 ° C. per minute, followed by firing treatment.

(Preparation of aqueous dispersion)
The YSZ particles before and after the firing treatment were pulverized and dispersed in water using a wet type bead mill. Crushing was performed while confirming the particle size, and the dispersion was collected when the particle size distribution reached 0.2 to 1 μm.

(Comparative Example 4)
(Preparation of Ba (CH ₃ COO) ₂ / TTIP dehydration condensate solution)
To 20.8 parts by weight of acetic acid, 8.09 parts by weight of barium acetate was added and stirred at 60 ° C. to dissolve.

Furthermore, 9.1 parts by weight of titanium tetraisopropoxide (TTIP) was added, stirred at room temperature, and further diluted with 83.76 parts by weight of water to prepare a Ba (CH ₃ COO) ₂ / TTIP dehydrated condensate solution. The dehydrated condensate was poured into a spray dryer, pressurized (0.2 MPa) at a nozzle outlet temperature of 190 ° C., and sprayed to obtain barium titanate particles.

(Formation of barium titanate particles)
The obtained barium titanate particles were heated and fired at a rate of 5 ° C. per minute from room temperature to 600 ° C. using an electric furnace.

(Preparation of aqueous dispersion)
The barium titanate particles before and after the firing treatment were pulverized and dispersed in water using a wet type bead mill. Crushing was performed while confirming the particle size, and the dispersion was collected when the particle size distribution reached 0.2 to 1 μm.

(Comparative Example 5)
Titanium dioxide powder (Ishihara Sangyo TTO-51 (A)) was pulverized and dispersed in water using a wet type bead mill. Grinding was performed while confirming the particle size, and the dispersion was collected when the particle size distribution reached 0.2 μm.
As mentioned above, the following evaluation was performed about the aqueous dispersion obtained by the Example comparative example.

(1. Specific surface area, pore volume, pore size distribution)
The porous particle aqueous dispersions of Examples 1 to 8 and the aqueous dispersions of Comparative Examples 1 to 5 were subjected to drying treatment to recover the powder, and using Autosorb 3 (manufactured by Kantachrome) under liquid nitrogen temperature ( The specific surface area (BET method), pore volume, and pore distribution (BJH method) were measured by the nitrogen gas adsorption method at 77K). In addition, when a reliable pore volume value cannot be obtained, it is determined as “impossible to measure”, and the pore distribution is below the detection limit (<2 nm), and a clear value cannot be obtained in the measurement of the pore distribution. In the case, it was decided that it could not be specified. The results are shown in Table 1, Table 2, and Table 3.

(2. Crystal structure)
The aqueous dispersion was dried and the powder was collected and measured with a powder X-ray analyzer (Rigaku MultiFlex, CuKα ray: 1.5418 mm) to examine the crystal structure. The results are shown in Table 1, Table 2, and Table 3.

(3. Dispersibility)
The aqueous dispersion was allowed to stand and the sedimentation state of the particles was evaluated.
The evaluation criteria are as follows. The results are shown in Table 1, Table 2, and Table 3.
◎: No sedimentation after standing for 1 week ○: Gradually settled, dispersed immediately when shaked ×: Immediately settled, water layer and sediment completely separated

(4. Evaluation of aqueous composition)
An aqueous composition added so that the dry weight of the acrylic emulsion (Almatex) as a fixing resin is 10 parts by weight with respect to the dry weight of 90 parts by weight of the aqueous dispersion is applied to the PET film surface using a wire bar. The coating was made to have a thickness of 3 μm and 15 μm, and the following evaluation was performed. The results are shown in Table 1, Table 2, and Table 3.

(4.1. Properties and application state of aqueous composition)
The evaluation criteria are as follows.
A: The composition does not gel, and there is no problem with the smoothness of the coat film. Δ: The composition does not gel, but the coat film is not smooth.

(4.2. Whiteness)
An aqueous composition added so that the dry weight of the acrylic emulsion (Almatex) as a fixing resin is 10 parts by weight with respect to the dry weight of 90 parts by weight of the aqueous dispersion is applied to the PET film surface using a wire bar. The film was coated to a thickness of 3 μm, and the whiteness was measured. The measurement was carried on a standard black plate, and the color was measured using a spectral color / whiteness meter (PF-10, Nippon Denshoku Industries Co., Ltd.). The lightness (L *) obtained at this time was used as an index of whiteness. The evaluation criteria for whiteness are as follows. The results are shown in Table 1, Table 2, and Table 3.

<Evaluation criteria for whiteness>
A: L * is 75 or more A: L * is 72 or more and less than 75 B: L * is 68 or more and less than 72 C: L * is 65 or more and less than 68 D: L * is less than 65 −: A measurable coat film is prepared Can not.

(5. Light resistance)
Using the porous particle aqueous dispersion of Example 3 and Example 5, the coating film prepared on the surface of the PET film prepared by the same method as in Evaluation 4.2 was irradiated using a solar simulator to change the film surface. Examined.
In Example 3, the film surface did not become brittle until irradiation for 120 hours. In Example 5, there was no yellowing or embrittlement on the film surface even after irradiation for 500 hours.

(6. Pore structure)
A cross-section of the particle was cut out by focused ion beam (FIB) processing, and the shape of the cross-section was observed using a transmission electron microscope (TEM / H-7650 manufactured by Hitachi, Ltd.) at 200 kV. As a result, in Examples 1 to 8, the pores exhibited an ordered structure (cubic phase structure) and were arranged.

Claims (14)

(A) In a matrix mainly composed of a metal oxide having a refractive index of 1.8 or more at a wavelength of 589.3 nm (Na-D line), a 50% volume particle size is 10 to 300 nm and can be dispersed in an aqueous medium. An organic-inorganic composite in which organic polymer particles are dispersed, and / or (B) an average in a matrix mainly composed of metal oxide having a refractive index of 1.8 or more at a wavelength of 589.3 nm (Na-D line) A pigment for white aqueous ink for ink- jet printing, comprising a porous metal oxide in which pores having a pore diameter of 10 to 300 nm are dispersed. (A) the organic-inorganic composite and / or the (B) ink jet printing a white water-based ink pigment according to claim 1 the particle size of the metal oxide porous material is 0.1 .mu.m to 5 .mu.m. The pigment for white aqueous ink for ink- jet printing according to claim 1 or 2, wherein the metal oxide is titanium dioxide. 4. The white aqueous ink pigment for ink- jet printing according to claim 1, wherein the metal oxide is formed from titanium dioxide nanoparticles having a surface coated with zirconium dioxide. The organic polymer particles and / or ink jet printing white aqueous ink pigment according to any one of claims 1 to 4, wherein the pores are cubic phase structure dispersed in the metal oxide. The organic polymer particles are at least one selected from polyolefin, poly (meth) acrylate, polystyrene, polyurethane, polyacrylonitrile, polyvinyl chloride, polyvinylidene chloride, polyvinyl acetate and polybutadiene. The white water-based ink pigment for inkjet printing according to any one of claims 1 to 5 , wherein the pigment is a water-insoluble polymer particle of a kind. The organic polymer particles according to any one of claims 1 to 6, which is a number-average molecular weight of 2.5 × 10 ⁴ or less of the terminally branched polyolefin copolymer particles represented by the following general formula (1) White aqueous ink pigment for inkjet printing :
(In the formula, A represents a polyolefin chain. R ¹ and R ² represent a hydrogen atom or an alkyl group having 1 to 18 carbon atoms, and at least one of them is a hydrogen atom. X ¹ and X ² are the same. Or, differently, it represents a group having a linear or branched polyalkylene glycol group. In the terminal branched copolymer represented by the general formula (1), X ¹ and X ² are the same or different, and the general formula (2)
(In the formula, E represents an oxygen atom or a sulfur atom. X ³ represents a polyalkylene glycol group or the following general formula (3).
(In the formula, R ³ represents an m + 1 valent hydrocarbon group. G is the same or different and is represented by —OX ⁴ , —NX ⁵ X ⁶ (X ^{4 to} X ⁶ represent a polyalkylene glycol group). M represents the number of bonds between R ³ and G, and represents an integer of 1 to 10). )
Or general formula (4)
The inkjet printing according to claim 7 , wherein X ⁷ and X ⁸ are the same or different and represent a polyalkylene glycol group or a group represented by the general formula (3). Pigment for white aqueous ink. The pigment for white aqueous ink for ink- jet printing according to claim 7 or 8 , wherein the terminally branched copolymer is represented by the following general formula (1a) or general formula (1b):
(In the formula, R ⁴ and R ⁵ represent a hydrogen atom or an alkyl group having 1 to 18 carbon atoms, and at least one of them is a hydrogen atom. R ⁶ and R ⁷ represent a hydrogen atom or a methyl group, At least one of them is a hydrogen atom, R ⁸ and R ⁹ represent a hydrogen atom or a methyl group, and at least one of them is a hydrogen atom, l + m represents an integer of 2 to 450, n is 20 Represents an integer of 300 or more.)
(In the formula, R ⁴ and R ⁵ represent a hydrogen atom or an alkyl group having 1 to 18 carbon atoms, and at least one of them is a hydrogen atom. R ⁶ and R ⁷ represent a hydrogen atom or a methyl group, At least one of them is a hydrogen atom, R ⁸ and R ⁹ represent a hydrogen atom or a methyl group, at least one of them is a hydrogen atom, R ¹⁰ and R ¹¹ represent a hydrogen atom or a methyl group, At least one of them is a hydrogen atom, l + m + o represents an integer of 3 to 450, and n represents an integer of 20 to 300.) The pigment for a white aqueous ink for ink- jet printing according to any one of claims 1 to 6 , wherein the organic polymer particles are (meth) acrylic acid ester polymer particles. The white water-based ink composition for inkjet printing containing the pigment for white water-based inks for inkjet printing in any one of Claims 1-10 . An image such as a character, a picture, or a pattern recorded by the white aqueous ink composition for ink jet printing according to claim 11 . The printed matter printed on the base material using the white aqueous ink composition for inkjet printing according to claim 11 .   (B) Metal oxide in which pores having an average pore diameter of 10 to 300 nm are dispersed in a matrix mainly composed of a metal oxide having a refractive index of 1.8 or more at a wavelength of 589.3 nm (Na-D line) A method for producing a pigment for white aqueous ink for inkjet printing comprising a porous material,
  The porous metal oxide (B) has a 50% volume particle size in a matrix mainly composed of a metal oxide (A) having a refractive index of 1.8 or more at a wavelength of 589.3 nm (Na-D line). A white aqueous ink pigment for inkjet printing, which is obtained by removing the organic polymer particles from an organic-inorganic composite in which organic polymer particles dispersible in an aqueous medium and having a thickness of 10 to 300 nm are dispersed. Production method.