JP2013064053A - Water-resistant aluminum pigment dispersion, method of producing the pigment dispersion, and aqueous ink composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a water-resistant aluminum pigment dispersion that can be prevented from being whitened when blended in an aqueous coating material or an aqueous ink composition, has excellent metallic luster, and is particularly excellent in water dispersibility.SOLUTION: The water-resistant pigment dispersion is produced by dispersing in an aqueous medium, a water-resistant aluminum pigment whose surface is coated with a silica film. (A) polyoxyethylene alkyl ether phosphate ester or its salt and (B) a polymer having a repeating unit derived from maleic acid are introduced into the surface or inside of the silica film.

Description

  The present invention relates to a water-resistant aluminum pigment dispersion, a method for producing the same, and an aqueous ink composition containing the water-resistant aluminum pigment dispersion.

  Conventionally, as a method of forming a coating film having a metallic luster on a printed material, gold powder produced from brass, aluminum fine particles, etc., printing ink using silver powder as a pigment, foil press printing using metal foil, metal foil was used. Thermal transfer systems have been used.

  In recent years, there have been many examples of application to inkjet in printing, and one of them is metallic printing, and development of ink having metallic luster has been promoted. For example, Patent Document 1 discloses an aluminum pigment dispersion based on an organic solvent such as alkylene glycol and a non-aqueous ink composition containing the same.

  On the other hand, from the viewpoint of the global environment and the safety to the human body, there is a reality that development of a water-based ink composition is desired rather than a non-aqueous ink composition based on an organic solvent. However, when the aluminum pigment is dispersed in water, it generates hydrogen gas by reaction with water and forms alumina to whiten. Thereby, an aluminum pigment may impair metallic luster.

  In order to solve such a problem, for example, in Patent Document 2, an aluminum pigment whose surface is covered with a silica film to improve water resistance is dispersed in an aqueous solution containing polycarboxylic acid or a salt thereof. A water resistant aluminum pigment dispersion is disclosed. According to this water-resistant aluminum pigment dispersion, whitening due to the formation of alumina can be prevented and excellent metallic luster can be exhibited.

JP 2008-174712 A JP 2011-132483 A

  However, in a water-resistant aluminum pigment dispersion in which a water-resistant aluminum pigment whose surface is coated with a silica film is simply dispersed in an aqueous solution containing a polycarboxylic acid or a salt thereof, aggregation of aluminum pigments is suppressed to some extent. Although it was possible, it was still not enough. For example, when an ink composition containing the water-resistant aluminum pigment is applied to an ink jet printer, the water-resistant aluminum pigment may aggregate to cause nozzle clogging and ink ejection stability may be impaired. there were.

  Some aspects according to the present invention can prevent whitening when blended in a water-based paint or water-based ink composition by solving the above problems, and have excellent metallic gloss and water dispersibility. In particular, it provides a water-resistant aluminum pigment dispersion that is particularly good.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following aspects or application examples.

[Application Example 1]
One aspect of the water resistant aluminum pigment dispersion according to the present invention is:
A water-resistant aluminum pigment dispersion in which a water-resistant aluminum pigment whose surface is coated with a silica film is dispersed in an aqueous medium,
A polymer (B) having a repeating unit derived from polyoxyethylene alkyl ether phosphate ester or a salt thereof (A) and maleic acid is introduced on the surface or inside of the silica film.

[Application Example 2]
One aspect of the water resistant aluminum pigment dispersion according to the present invention is:
A step (a) of preparing an aluminum pigment dispersion in which an aluminum pigment is dispersed in an organic solvent;
Adding tetraethoxysilane to the aluminum pigment dispersion; and (b)
A step of adding a solution in which a polymer (B) having a repeating unit derived from polyoxyethylene alkyl ether phosphate ester or a salt thereof (A) and maleic acid is dissolved in an organic solvent into the aluminum pigment dispersion ( c) and
A step (d) of substituting at least a part of the organic solvent contained in the aluminum pigment dispersion with an aqueous medium;
It is obtained by the method containing.

  According to the water-resistant aluminum pigment dispersion of Application Example 1 or Application Example 2, it is possible to prevent whitening when blended in a water-based paint or water-based ink composition, and has excellent metallic gloss and water dispersibility. Especially good. Therefore, when the water-based ink composition using the water-resistant aluminum pigment dispersion of Application Example 1 or Application Example 2 is applied to an inkjet printer, nozzle clogging due to aggregation of the water-resistant aluminum pigments is suppressed. Ink ejection stability is improved.

[Application Example 3]
In the water-resistant aluminum pigment dispersion of Application Example 2, the aqueous medium may be an aqueous solution to which a polymer (B) having a repeating unit derived from maleic acid is added.

[Application Example 4]
In the water-resistant aluminum pigment dispersion of Application Example 2 or Application Example 3, the step (b) may further include adding a basic catalyst.

（上記式中、ｍは８〜１８の整数であり、ｎは２〜１０の整数である。Ｒは、水素、ナトリウム、カリウム及びモノエタノールアミンから選択される１種であり、式（１）中に２つ存在するＲは同一又は異なってもよい。） [Application Example 5]
In the water-resistant aluminum pigment dispersion of any one of Application Examples 1 to 4, the compound (A) may be a compound represented by the following general formula (1) or (2).

(In the above formula, m is an integer of 8 to 18, and n is an integer of 2 to 10. R is one selected from hydrogen, sodium, potassium and monoethanolamine, and the formula (1) And two Rs present therein may be the same or different.)

[Application Example 6]
In any one of Application Examples 1 to 5, the aluminum pigment is a tabular grain having an average thickness of 5 nm to 30 nm and a 50% average particle diameter of 0.5 μm to 3 μm. be able to.

（式中、Ａ_１及びＡ_２は、それぞれ独立に、水素、アルカリ金属又はアンモニウムを表す。）

[Application Example 7]
In any one example of Application Example 1 to Application Example 6, the polymer (B) includes at least one of repeating units represented by the following general formulas (3) and (4), and the following general formulas (5) and ( And a copolymer having at least one of the repeating units represented by 6).

(In the formula, A ₁ and A ₂ each independently represent hydrogen, an alkali metal, or ammonium.)

[Application Example 8]
One aspect of the water-based ink composition according to the invention is characterized by containing the water-resistant aluminum pigment dispersion of any one of Application Examples 1 to 7.

[Application Example 9]
One aspect of the method for producing a water-resistant aluminum pigment dispersion according to the present invention is as follows:
A step (a) of preparing an aluminum pigment dispersion in which an aluminum pigment is dispersed in an organic solvent;
Adding tetraethoxysilane to the aluminum pigment dispersion; and (b)
A step of adding a solution in which a polymer (B) having a repeating unit derived from polyoxyethylene alkyl ether phosphate ester or a salt thereof (A) and maleic acid is dissolved in an organic solvent into the aluminum pigment dispersion ( c) and
A step (d) of substituting at least a part of the organic solvent contained in the aluminum pigment dispersion with an aqueous medium;
It is characterized by including.

[Application Example 10]
In the method for producing a water-resistant aluminum pigment dispersion of Application Example 9, the aqueous medium may be an aqueous solution to which a polymer (B) having a repeating unit derived from maleic acid is added.

[Application Example 11]
In the method for producing a water-resistant aluminum pigment dispersion of Application Example 9 or Application Example 10, the step (b) may further include adding a basic catalyst.

（上記式中、ｍは８〜１８の整数であり、ｎは２〜１０の整数である。Ｒは、水素、ナトリウム、カリウム及びモノエタノールアミンから選択される１種であり、式（１）中に２つ存在するＲは同一又は異なってもよい。） [Application Example 12]
In the method for producing a water-resistant aluminum pigment dispersion according to any one of Application Example 9 to Application Example 11, the compound (A) may be a compound represented by the following general formula (1) or (2). .

(In the above formula, m is an integer of 8 to 18, and n is an integer of 2 to 10. R is one selected from hydrogen, sodium, potassium and monoethanolamine, and the formula (1) And two Rs present therein may be the same or different.)

[Application Example 13]
In the method for producing a water-resistant aluminum pigment dispersion according to any one of Application Example 9 to Application Example 12, the aluminum pigment has an average thickness of 5 nm to 30 nm and 50% of 0.5 μm to 3 μm. It can be a tabular grain having an average grain size.

（式中、Ａ_１及びＡ_２は、それぞれ独立に、水素、アルカリ金属又はアンモニウムを表す。）

[Application Example 14]
In the method for producing a water-resistant aluminum pigment dispersion according to any one of Application Example 9 to Application Example 13, the polymer (B) is at least one of repeating units represented by the following general formulas (3) and (4). And at least one of the repeating units represented by the following general formulas (5) and (6).

(In the formula, A ₁ and A ₂ each independently represent hydrogen, an alkali metal, or ammonium.)

  Hereinafter, preferred embodiments of the present invention will be described. The embodiment described below describes an example of the present invention. In addition, the present invention is not limited to the following embodiments, and includes various modifications that are implemented within a range that does not change the gist of the present invention.

  Hereinafter, a method for producing a water-resistant aluminum pigment dispersion, a water-resistant aluminum pigment dispersion, and a water-based ink composition will be described in this order.

1. Method for Producing Water-Resistant Aluminum Pigment Dispersion A method for producing a water-resistant aluminum pigment dispersion according to an embodiment of the present invention includes a step (a) of preparing an aluminum pigment dispersion in which an aluminum pigment is dispersed in an organic solvent, A step (b) of adding tetraethoxysilane to the aluminum pigment dispersion, and a polymer (B) having a repeating unit derived from a polyoxyethylene alkyl ether phosphate or a salt thereof (A) and maleic acid A step (c) of adding a solution dissolved in an organic solvent to the aluminum pigment dispersion; and a step (d) of substituting at least a part of the organic solvent contained in the aluminum pigment dispersion with an aqueous medium. It is characterized by including these. Hereinafter, each process mentioned above is demonstrated in detail.

1.1. Step (a)
Step (a) is a step of preparing an aluminum pigment dispersion in which an aluminum pigment is dispersed in an organic solvent.

  First, a composite pigment base having a structure in which a release resin layer and an aluminum or aluminum alloy layer (hereinafter simply referred to as “aluminum layer”) are sequentially laminated on a sheet-like substrate surface is prepared.

  Although it does not restrict | limit especially as a sheet-like base material, Polytetrafluoroethylene, polyethylene, polypropylene, Polyester films, such as a polyethylene terephthalate, Polyamide films, such as nylon 66 and nylon 6, Polycarbonate films, a triacetate film, a polyimide film, etc. A functional film. Of these, polyethylene terephthalate or a copolymer thereof is preferable.

  The thickness of the sheet-like substrate is not particularly limited, but is preferably 10 μm or more and 150 μm or less. If it is 10 μm or more, there is no problem in handleability in the process or the like, and if it is 150 μm or less, it is rich in flexibility and there is no problem in roll formation / peeling.

  The release resin layer is an undercoat layer of an aluminum layer, and is a peelable layer for improving the peelability from the sheet-like substrate surface. As the resin used for the release resin layer, for example, polyvinyl alcohol, polyvinyl butyral, polyethylene glycol, polyacrylic acid, polyacrylamide, cellulose derivative, acrylic acid polymer, or modified nylon resin is preferable.

  The resin layer for peeling can be formed by applying a solution of one or two or more of the resins exemplified above to a sheet-like substrate and drying it. After coating, additives such as a viscosity modifier can be added.

  For the application of the release resin layer, commonly used techniques such as gravure coating, roll coating, blade coating, extrusion coating, dip coating, and spin coating can be used. After coating and drying, the surface can be smoothed by calendaring if necessary.

  The thickness of the release resin layer is not particularly limited, but is preferably 0.5 μm or more and 50 μm or less, and more preferably 1 μm or more and 10 μm or less. If it is less than 0.5 μm, the amount as a dispersion resin is insufficient, and if it exceeds 50 μm, when it is rolled, it tends to peel off at the interface with the pigment layer.

  As means for laminating the aluminum layer, it is preferable to apply vacuum deposition, ion plating or sputtering.

  The aluminum layer may be sandwiched between protective layers as exemplified in JP-A-2005-68250. Examples of the protective layer include a silicon oxide layer and a protective resin layer.

  The silicon oxide layer is not particularly limited as long as it is a layer containing silicon oxide, but is preferably formed from a silicon alkoxide such as tetraalkoxysilane or a polymer thereof by a sol-gel method. A coating film of a silicon oxide layer can be formed by applying an alcohol solution in which silicon alkoxide or a polymer thereof is dissolved, followed by heating and baking.

  The protective resin layer is not particularly limited as long as it is a resin that does not dissolve in the dispersion medium, and examples thereof include polyvinyl alcohol, polyethylene glycol, polyacrylic acid, polyacrylamide, and cellulose derivatives. Of these, it is preferably formed from polyvinyl alcohol or a cellulose derivative.

  A protective resin layer can be formed by applying and drying an aqueous solution of one or more of the above exemplified resins. Additives such as a viscosity modifier can be further added to the coating solution. The silicon oxide and the resin are applied by the same method as the application of the release resin layer.

  The thickness of the protective layer is not particularly limited, but is preferably in the range of 50 nm to 150 nm. If it is less than 50 nm, the mechanical strength is insufficient, and if it exceeds 150 nm, the strength becomes too high, so that pulverization / dispersion becomes difficult, and peeling may occur at the interface with the aluminum layer.

  Moreover, as illustrated in US Pat. No. 7,303,619, the composite pigment base may have a color material layer between the protective layer and the aluminum layer.

  The color material layer is introduced to obtain an arbitrary colored composite pigment, and in addition to the metallic luster, glitter, and background hiding properties of the aluminum pigment used in the present embodiment, a color that can impart an arbitrary color tone and hue. There is no particular limitation as long as the material can be contained. As the color material used for this color material layer, either a dye or a pigment may be used. Moreover, as a dye and a pigment, a well-known thing can be used suitably.

  In such a case, the “pigment” used in the color material layer means a natural pigment, a synthetic organic pigment, a synthetic inorganic pigment or the like defined in the general engineering field.

  The method for forming the color material layer is not particularly limited, but is preferably formed by coating. Further, when the color material used in the color material layer is a pigment, it is preferable to further include a color material dispersion resin. Examples of the color material dispersion resin include a pigment, a color material dispersion resin, and other materials as necessary. It is preferable that the additive is dispersed or dissolved in a solvent to form a uniform liquid film by spin coating as a solution and then dried to produce a resin thin film. In the production of the composite pigment raw material, it is preferable in terms of work efficiency that both the colorant layer and the protective layer are formed by coating.

  As the composite pigment base material, a layer structure having a plurality of sequentially laminated structures of a release resin layer and an aluminum layer is also possible. At that time, the total thickness of the laminated structure composed of a plurality of aluminum layers, that is, excluding the sheet-like base material and the peeling resin layer immediately above the aluminum layer—the peeling resin layer—the aluminum layer or the peeling resin layer— The thickness of the aluminum layer is preferably 5000 nm or less. When it is 5000 nm or less, even when the composite pigment base material is rolled up, it is difficult to cause cracking and peeling and is excellent in storage stability. Moreover, it is excellent also in the metal glossiness when it is pigmented. Moreover, although the structure where the peeling resin layer and the aluminum layer were laminated | stacked one by one on both surfaces of the sheet-like base material surface is mentioned, it is not restrict | limited to these.

  Next, the composite pigment base material is peeled from the composite pigment base material in an organic solvent at the interface between the sheet base surface of the composite pigment base material and the release resin layer as a boundary, and then pulverized or refined By processing, an aluminum pigment dispersion containing coarse particles is obtained. Furthermore, the obtained aluminum pigment dispersion is filtered to remove coarse particles, whereby an aluminum pigment dispersion containing aluminum tabular particles can be obtained.

  Any organic solvent may be used as long as it does not impair the dispersion stability of the aluminum pigment and the reactivity with tetraethoxysilane described later, but a polar organic solvent is preferable. Examples of polar organic solvents include alcohols (methyl alcohol, ethyl alcohol, propyl alcohol, butyl alcohol, isopropyl alcohol, fluorinated alcohol, etc.), ketones (acetone, methyl ethyl ketone, cyclohexanone, etc.), carboxylic acid esters (methyl acetate, Ethyl acetate, propyl acetate, butyl acetate, methyl propionate, ethyl propionate, etc.), ethers (diethyl ether, dipropyl ether, tetrahydrofuran, dioxane, etc.) and the like.

  Among the polar organic solvents exemplified above, alkylene glycol monoether or alkylene glycol diether which is liquid at normal temperature and pressure is more preferable.

  As alkylene glycol monoether, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monoisopropyl ether, ethylene glycol monobutyl ether, ethylene glycol monohexyl ether, ethylene glycol monophenyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, Diethylene glycol monobutyl ether, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, triethylene glycol monobutyl ether, tetraethylene glycol monomethyl ether, tetraethylene glycol monoethyl ether, propylene glycol monomethyl ether, propylene group Monoethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether and the like.

  Examples of the alkylene glycol diether include ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dibutyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol dibutyl ether, triethylene glycol dimethyl ether, triethylene glycol diethyl ether, triethylene glycol dibutyl ether, tetra Ethylene glycol dimethyl ether, tetraethylene glycol diethyl ether, tetraethylene glycol dibutyl ether, propylene glycol dimethyl ether, propylene glycol diethyl ether, dipropylene glycol dimethyl ether, dipropylene glycol diethyl ether, etc. It is below.

  Among these, triethylene glycol monobutyl ether and diethylene glycol diethyl ether are more preferable from the viewpoint of excellent dispersion stability of the aluminum pigment. In consideration of continuity with the subsequent step of imparting water resistance to the aluminum pigment, diethylene glycol diethyl ether is particularly preferable.

  The peeling treatment method from the sheet-like substrate is not particularly limited, but is a method that is performed by immersing the composite pigment raw material in a liquid, or the ultrasonic treatment is performed at the same time as the immersion in the liquid. A method of pulverizing the composite pigment thus obtained is preferred.

  The aluminum pigment composed of tabular grains obtained as described above has a release resin layer serving as a protective colloid, and a stable dispersion can be obtained simply by performing a dispersion treatment in an organic solvent. It is.

  The aluminum pigment in the aluminum pigment dispersion obtained by the above process becomes tabular grains. It is preferable that the aluminum pigment is a tabular particle in that good metallic luster is easily obtained. Here, the term “tabular particle” refers to an aluminum particle having a substantially flat surface (XY plane) when the major axis on the plane is X, the minor axis is Y, and the thickness is Z. (Z) refers to particles that are substantially uniform. More specifically, the 50% average particle diameter R50 (hereinafter also simply referred to as “R50”) of the equivalent circle diameter determined from the area of the substantially flat surface (XY plane) of the aluminum particles is 0.5 μm or more and 3 μm. And the thickness (Z) satisfies 5 nm or more and 30 nm or less. The aluminum pigment of the present invention is not limited to a flat plate shape.

  The “equivalent circle diameter” is the diameter of the circle when assuming that the substantially flat surface (XY plane) of the aluminum particles is a circle having the same projected area as the projected area of the aluminum particles. For example, when the substantially flat surface (XY plane) of an aluminum particle is a polygon, the diameter of the circle obtained by converting the polygonal projection surface into a circle is the equivalent circle diameter of the aluminum particle. That's it.

  The 50% average particle diameter R50 of the equivalent-circle diameter determined from the area of the substantially flat surface (XY plane) of the tabular grains is preferably from the viewpoint of ensuring good metal gloss and printing stability. It is preferably 5 μm or more and 3 μm or less, and more preferably 0.75 μm or more and 2 μm or less. When R50 is less than 0.5 μm, the metallic gloss may be insufficient. On the other hand, when R50 exceeds 3 μm, the printing stability may be lowered.

  The major axis X, minor axis Y, and equivalent circle diameter on the plane of the tabular grain can be measured using a particle image analyzer. Examples of the particle image analyzer include a flow type particle image analyzer FPIA-2100, FPIA-3000, and FPIA-3000S (manufactured by Sysmex Corporation).

The particle size distribution (CV value) of the tabular grains can be obtained from the following formula (7).
CV value = standard deviation of particle size distribution / average value of particle diameter × 100 (7)
Here, the CV value obtained is preferably 60 or less, more preferably 50 or less, and particularly preferably 40 or less. By selecting tabular grains having a CV value of 60 or less, an effect of excellent printing stability can be obtained.

  The thickness (Z) is preferably 5 nm or more and 30 nm or less, more preferably 10 nm or more and 25 nm or less, from the viewpoint of securing metallic gloss. When the thickness (Z) is less than 5 nm, the metallic gloss tends to decrease when a silica film is formed on the surface of the aluminum particles. On the other hand, even if the thickness (Z) exceeds 30 nm, the metallic gloss tends to decrease.

  The aluminum pigment is preferably aluminum or an aluminum alloy from the viewpoint of cost and ensuring the metallic luster. In the case of using an aluminum alloy, examples of other metal elements or non-metal elements added in addition to aluminum include silver, gold, platinum, nickel, chromium, tin, zinc, indium, titanium, and copper.

  In addition, you may provide separately the process of wash | cleaning the aluminum pigment contained in the aluminum pigment dispersion liquid obtained by said process. The organic solvent mentioned above can be used for washing | cleaning of an aluminum pigment.

  The aluminum pigment dispersion may contain the aforementioned release resin layer, or the release resin layer may adhere to the aluminum pigment. The component contained in the release resin layer may inhibit the reaction between tetraethoxysilane and an aluminum pigment, which will be described later. Therefore, by washing the aluminum pigment, the components of the peeling resin layer can be removed, and the reactivity between tetraethoxysilane and the aluminum pigment, which will be described later, can be improved.

  Although it does not specifically limit as a washing | cleaning method of an aluminum pigment, For example, it can carry out by the following methods.

  First, at least a part of the organic solvent is removed from the aluminum pigment dispersion. For removing the organic solvent, the organic solvent and the aluminum pigment are separated by an operation such as filtration, centrifugal sedimentation, or centrifugal separation to remove the organic solvent contained in the aluminum pigment dispersion.

  Next, an organic solvent for washing is added to the aluminum pigment to disperse the aluminum pigment in the organic solvent, and then the organic solvent for washing is removed. The operation of dispersing the aluminum pigment in the cleaning organic solvent and removing the cleaning organic solvent may be performed a plurality of times.

  Thereafter, an aluminum pigment dispersion containing the washed aluminum pigment can be obtained by adding and dispersing the above-described organic solvent to the aluminum pigment.

1.2. Step (b)
Step (b) is a step of adding tetraethoxysilane (hereinafter also referred to as “TEOS”) to the aluminum pigment dispersion obtained in step (a) and stirring. By adding TEOS and stirring sufficiently, the hydroxyl groups present on the surface of the aluminum pigment and the silanol groups of TEOS are hydrolyzed and condensed to form a silica film on the surface of the aluminum pigment. Thereby, since it can suppress that aluminum and water contact directly, water resistance is provided to an aluminum pigment.

  The reaction temperature in the hydrolysis condensation is preferably 10 ° C. or higher and 150 ° C. or lower, more preferably 20 ° C. or higher and 130 ° C. or lower. If it is less than 10 degreeC, the progress of hydrolysis condensation will become slow and formation of the silica film on the surface of an aluminum pigment will become inadequate. If it exceeds 150 ° C, special safety precautions are required.

  The reaction time in the hydrolysis condensation is preferably 0.5 hours or more and 200 hours or less, more preferably 1 hour or more and 180 hours or less. When the reaction time is less than 0.5 hour, the hydrolysis and condensation may not be sufficiently completed, and an aluminum pigment having sufficient water resistance may not be obtained. If it exceeds 200 hours, the aluminum pigment may aggregate.

  The addition amount of TEOS may be determined by calculating an amount such that the thickness of the silica film is 0.5 nm or more and 10 nm or less, preferably 5 nm. This is because if the thickness of the silica film exceeds 10 nm, the metallic gloss may be lowered.

  More specifically, the addition amount of TEOS is preferably 0.2 parts by mass or more and 5 parts by mass or less, and 0.5 parts by mass or more and 4 parts by mass or less with respect to 1 part by mass of the aluminum pigment. Is more preferable, and it is particularly preferably 1 part by mass or more and 3 parts by mass or less. When the addition amount of TEOS exceeds 5 parts by mass, unreacted TEOS may form independent silica particles, which may cause the aluminum pigment dispersion to become cloudy. On the other hand, if it is less than 0.2 parts by mass, the hydroxyl group present on the surface of the aluminum pigment may not be completely hydrolytically condensed.

  In step (b), after addition of TEOS, a basic catalyst may be further added to promote hydrolysis and condensation. Examples of the basic catalyst include ammonia, trialkylamine, ethanolamine, sodium hydroxide, potassium hydroxide, urea, choline, tetraalkylammonium hydroxide, and the like. Among these, ammonia is particularly preferable.

  The addition amount of the basic catalyst is preferably 1 part by mass or less, more preferably 0.1 part by mass or less, with respect to 10 parts by mass of the aluminum pigment. If the addition amount of the basic catalyst exceeds the above range, the viscosity of the aluminum pigment dispersion may increase, or the aluminum pigment in the aluminum pigment dispersion may aggregate and the metallic luster may not be maintained.

1.3. Step (c)
In step (c), in the aluminum pigment dispersion obtained in step (b), polyoxyethylene alkyl ether phosphate or a salt thereof (A) (hereinafter also referred to as “compound (A)”) and maleic acid Is a step of adding and stirring a solution in which a polymer (B) having a repeating unit derived from (hereinafter also referred to as “polymer (B)”) is dissolved in an organic solvent. Thereby, the compound (A) and the polymer (B) are introduced into the surface or inside of the silica film formed on the surface of the aluminum pigment, thereby improving water dispersibility (that is, suppressing aggregation of aluminum pigments). be able to.

  First, the compound (A) and the polymer (B) are added to an organic solvent and sufficiently stirred to prepare a solution in which the compound (A) and the polymer (B) are completely dissolved.

（上記式中、ｍは８〜１８の整数であり、ｎは２〜１０の整数である。Ｒは、水素、ナトリウム、カリウム及びモノエタノールアミンから選択される１種であり、式（１）中に２つ存在するＲは同一又は異なってもよい。） The compound (A) is not particularly limited as long as it is a polyoxyethylene alkyl ether phosphate ester or a salt thereof, but is preferably a compound represented by the following general formula (1) or (2).

(In the above formula, m is an integer of 8 to 18, and n is an integer of 2 to 10. R is one selected from hydrogen, sodium, potassium and monoethanolamine, and the formula (1) And two Rs present therein may be the same or different.)

  Although it is difficult to dissolve the polymer (B) by adding it alone to the organic solvent, the polymer (B) can be obtained by adding the compound represented by the general formula (1) or (2). ) Can be solubilized in an organic solvent, and a transparent solution is obtained. The solution in which the polymer (B) is completely dissolved is added to the aluminum pigment dispersion obtained in the step (b) and sufficiently stirred, so that the silica film formed on the surface of the aluminum pigment is obtained. The compound (A) and the polymer (B) can be introduced on the surface or inside. Thereby, the water dispersibility of the aluminum pigment provided with water resistance is greatly improved.

  In said general formula (1) or (2), m is an integer of 8-18, and it is more preferable that it is an integer of 12-18. Although the mechanism is not clear, when m is an integer of 12 to 18, not only the water dispersibility is further improved, but also a water resistant aluminum pigment dispersion having good water resistance and metallic gloss is obtained. .

  Examples of commercially available compounds represented by the above general formula (1) or (2) include Prisurf A208F (trade name, manufactured by Daiichi Kogyo Seiyaku Co., Ltd., polyoxyethylene alkyl (C8) ether phosphate ester. ), Prisurf A210D (trade name, manufactured by Daiichi Kogyo Seiyaku Co., Ltd., polyoxyethylene alkyl (C10) ether phosphate ester), Prisurf DB-01 (trade name, manufactured by Daiichi Kogyo Seiyaku Co., Ltd., polyoxyethylene) Lauryl ether phosphate monoethanolamine salt), PRISURF A208B (trade name, manufactured by Daiichi Kogyo Seiyaku Co., Ltd., polyoxyethylene lauryl ether phosphate ester), Phosphanol RD-720 (trade name, Toho Chemical Industry) Co., Ltd., sodium polyoxyethylene oleyl ether phosphate) It is below.

  In addition, the HLB value of a compound (A) becomes like this. Preferably it is 5-18, More preferably, it is 6-16. When the HLB value exceeds 18, the hydrophobic / hydrophilic balance becomes hydrophilic, so that it becomes difficult to dissolve in an organic solvent, and a transparent solution in which the compound (A) and the polymer (B) are dissolved is obtained. It may not be obtained. On the other hand, when the HLB value is less than 5, the balance of hydrophobicity / hydrophilicity is on the hydrophobic side, so that the compound (A) may precipitate when substituting into the aqueous medium in the step (d) described later. It is not preferable.

（式中、Ａ_１及びＡ_２は、それぞれ独立に、水素、アルカリ金属又はアンモニウムを表す。）

The polymer (B) is not particularly limited as long as it is a polymer having a repeating unit derived from maleic acid, but at least one of the repeating units represented by the following general formulas (3) and (4) and the following general formula A copolymer having at least one of the repeating units represented by formulas (5) and (6) is preferable.

(In the formula, A ₁ and A ₂ each independently represent hydrogen, an alkali metal, or ammonium.)

  The copolymer may be any copolymer such as an alternating copolymer, a random copolymer, a block copolymer, and a graft copolymer.

  The above copolymer has a bulky molecular structure, and when introduced on the surface of a silica film formed on the surface of an aluminum pigment, it can suppress aggregation of aluminum pigments due to its steric hindrance. Conceivable.

  The weight average molecular weight (Mw) of the copolymer is preferably 2000 or more and 500,000 or less, and more preferably 10,000 or more and 100,000 or less. When the weight average molecular weight exceeds the above range, the viscosity of the aluminum pigment dispersion increases, and the water dispersibility may deteriorate. On the other hand, when the weight average molecular weight is less than the above range, the steric hindrance effect of the copolymer cannot be expected, and the water dispersibility of the aluminum pigment dispersion may deteriorate. In addition, a weight average molecular weight can be measured by gel permeation chromatography (GPC) using tetrahydrofuran as a solvent, for example, and can be calculated | required by the polystyrene conversion molecular weight.

  Examples of the above-mentioned copolymers that are commercially available include Polystar OM (trade name, manufactured by NOF Corporation, sodium salt of maleic anhydride-diisobutylene copolymer, Mw 5000), and Demol EP (trade name, Kao Corporation). And a maleic acid-diisobutylene copolymer).

  Moreover, as an organic solvent in which the compound (A) and the polymer (B) are dissolved, the organic solvent exemplified in the step (a) can be used, but it is the same as the organic solvent used in the step (a). Alternatively, an organic solvent having a similar chemical structure is preferable. By doing in this way, since the organic solvent and the transparent solution which melt | dissolved the compound (A) and the polymer (B) contained in an aluminum pigment dispersion liquid can be arbitrarily mixed, it is preferable. Therefore, as described in the step (a), the organic solvent is more preferably triethylene glycol monobutyl ether or diethylene glycol diethyl ether, and particularly preferably diethylene glycol diethyl ether.

  The content of the compound (A) in the transparent solution containing the compound (A) and the polymer (B) is not particularly limited as long as the amount can completely solubilize the polymer (B). In addition, the content of the polymer (B) is not particularly limited as long as it can be completely solubilized in the organic solvent, and can be appropriately adjusted according to the content of the compound (A).

  The transparent solution containing the compound (A) and the polymer (B) can be obtained by adding the compound (A) and the polymer (B) to the organic solvent and stirring sufficiently. The stirring time is preferably 5 hours or longer, more preferably 8 hours or longer and 24 hours or shorter.

  Next, the obtained transparent solution is added to the aluminum pigment dispersion and sufficiently stirred. The stirring time is preferably 12 hours or longer, more preferably 18 hours or longer and 48 hours or shorter. When the reaction time is 12 hours or longer, the compound (A) and the polymer (B) can be sufficiently introduced into the silica film, and good water dispersibility can be imparted.

1.4. Step (d)
Step (d) is a step of replacing at least part of the organic solvent contained in the aluminum pigment dispersion obtained in step (c) with an aqueous medium.

  By the step (d), the organic solvent in the aluminum pigment dispersion obtained in the step (c) can be replaced with an aqueous medium, and a water-resistant aluminum pigment dispersion excellent in water dispersibility is obtained. Moreover, since the solvent of the water resistant aluminum pigment dispersion obtained by the step (d) is based on an aqueous medium, it can be easily applied to an aqueous ink composition.

  The aqueous medium may be a medium containing water as a main component, for example, water or an aqueous surfactant solution. The water is preferably pure water or ultrapure water such as ion exchange water, ultrafiltration water, reverse osmosis water, or distilled water. In particular, water obtained by sterilizing these waters by ultraviolet irradiation or addition of hydrogen peroxide is preferable because generation of mold and bacteria can be suppressed over a long period of time.

  Examples of the surfactant include an anionic surfactant, a cationic surfactant, a nonionic surfactant, an amphoteric surfactant, and a polymer surfactant. Among these, a polymer surfactant is more preferable, and a polymer (B) having a repeating unit derived from maleic acid is more preferable, which is represented by the above general formulas (3) and (4). A copolymer having at least one of repeating units and at least one of the repeating units represented by the general formulas (5) and (6) is particularly preferable.

  The addition amount of the surfactant is preferably 0.05 parts by mass or more and 2.0 parts by mass or less, more preferably 0.1 parts by mass or more and 1.5 parts by mass or less, particularly preferably with respect to 1 part by mass of the aluminum pigment. Is preferably added so as to be 0.1 parts by mass or more and 1.2 parts by mass or less. When the addition amount of the surfactant exceeds the above range, the water dispersibility of the water resistant aluminum pigment dispersion may be deteriorated. On the other hand, when the addition amount of the surfactant is less than the above range, aggregation of the aluminum pigment occurs, and the metallic gloss may not be maintained.

  The removal of the organic solvent contained in the aluminum pigment dispersion obtained in the step (c) is carried out by filtering the organic solvent and the aluminum pigment having the silica film formed on the surface by an operation such as filtration, centrifugal sedimentation or centrifugation. The organic solvent contained in the aluminum pigment dispersion is removed by separation. Since it is simple among the above operations, a method of separating the organic solvent by centrifugation is preferable. By these methods, it is preferable to remove 70% or more of the organic solvent contained in the aluminum pigment dispersion, and it is more preferable to remove 80% or more.

  Next, the above aqueous medium is added to the aluminum pigment dispersion from which at least a part of the organic solvent has been removed, and the mixture is sufficiently stirred. The stirring time after the addition of the aqueous medium is not particularly limited, but is preferably 3 hours or more and 120 hours or less. When the stirring time is within the above range, a water-resistant aluminum pigment dispersion having excellent water dispersibility can be obtained without impairing the metallic luster.

  By passing through the steps (a) to (d) as described above, whitening can be prevented when blended in a water-based paint or water-based ink composition, and it has excellent metallic gloss and water dispersibility. Particularly good water resistant aluminum pigment dispersions can be produced.

2. Water-Resistant Aluminum Pigment Dispersion The water-resistant aluminum pigment dispersion according to the present embodiment is obtained by the production method described above. That is, the water-resistant aluminum pigment dispersion according to the present embodiment includes a step (a) of preparing an aluminum pigment dispersion in which an aluminum pigment is dispersed in an organic solvent, and tetraethoxysilane in the aluminum pigment dispersion. Step (b) to be added, and a solution prepared by dissolving a polymer (B) having a repeating unit derived from polyoxyethylene alkyl ether phosphate or a salt thereof (A) and maleic acid in an organic solvent. It is obtained by a method comprising a step (c) of adding to a dispersion and a step (d) of substituting at least a part of the organic solvent contained in the aluminum pigment dispersion with an aqueous medium. To do.

  Moreover, the water-resistant aluminum pigment obtained by the manufacturing method described above has the following characteristics. That is, the water-resistant aluminum pigment dispersion according to the present embodiment is a water-resistant aluminum pigment dispersion in which a water-resistant aluminum pigment whose surface is coated with a silica film is dispersed in an aqueous medium. A polymer (B) having a repeating unit derived from polyoxyethylene alkyl ether phosphate ester or salt (A) and maleic acid is introduced on the surface or inside of the membrane.

  According to the water-resistant aluminum pigment dispersion according to the present embodiment, water resistance is imparted by forming a silica film on the surface of the aluminum pigment, so that when it is blended in a water-based paint or water-based ink composition It can prevent whitening and has excellent metallic luster. Moreover, since the compound (A) and the polymer (B) are introduced on the surface or inside of the silica film, the water-resistant aluminum pigment dispersion is particularly excellent in water dispersibility.

  As described above, the aluminum pigment before the formation of the silica film has a flat aluminum having an average thickness of 5 nm to 30 nm and a 50% average particle diameter (R50) of 0.5 μm to 3 μm. Particles are preferred.

  The thickness of the silica film is preferably 0.5 nm or more and 10 nm or less, and more preferably 1 nm or more and 9 nm or less. If the thickness of the silica film is less than 0.5 nm, sufficient water resistance and water dispersibility cannot be imparted to the aluminum pigment. On the other hand, when the thickness of the silica film exceeds 10 nm, water resistance and water dispersibility can be imparted to the aluminum pigment, but the metal gloss tends to decrease.

The determination as to whether or not the compound (A) or the polymer (B) is introduced into the surface or inside of the silica film formed on the surface of the aluminum pigment can be made by, for example, X-ray photoelectron spectroscopy (hereinafter referred to as “XPS”). By means of elemental analysis, and ¹ H-NMR spectrum, ¹³ C-NMR spectrum, and ³¹ P-NMR spectrum.

  XPS is a spectroscopic method that measures the energy of photoelectrons emitted from a sample by X-ray irradiation. Since photoelectrons collide with molecules and are scattered immediately in the atmosphere, it is necessary to keep the apparatus in a vacuum. Also, photoelectrons emitted deep inside the solid sample are scattered within the sample and cannot escape from the surface. Therefore, XPS is effective as a surface analysis method because it measures photoelectrons only from the sample surface. In XPS, a range within a few nm from the sample surface can be analyzed.

3. Water-based ink composition The water-based ink composition according to this embodiment is characterized by containing the water-resistant aluminum pigment dispersion described above. In the present specification, the “aqueous ink composition” refers to an ink composition containing 50% by mass or more, preferably 70% by mass or more of water as a solvent. It is preferable to use pure water or ultrapure water such as ion exchange water, ultrafiltered water, reverse osmosis water, or distilled water. In particular, water obtained by sterilizing these waters by ultraviolet irradiation or addition of hydrogen peroxide is preferable because generation of mold and bacteria can be suppressed over a long period of time.

  The concentration of the water-resistant aluminum pigment in the aqueous ink composition according to the present embodiment is preferably 0.1 to 5.0% by mass, more preferably 0.1 to 3%, based on the total mass of the aqueous ink composition. 0.0 mass%, more preferably 0.25 to 2.5 mass%, particularly preferably 0.5 to 2.0 mass%.

  Resin, surfactant, alkanediol, polyhydric alcohol, pH adjuster, etc. can be added to the water-based ink composition according to the present embodiment.

  The resins have a function of firmly fixing the water-resistant aluminum pigment on the recording medium. Examples of the resins include acrylic acid, acrylic acid ester, methacrylic acid, methacrylic acid ester, acrylonitrile, cyanoacrylate, acrylamide, olefin, styrene, vinyl acetate, vinyl chloride, vinyl alcohol, vinyl ether, vinyl pyrrolidone, vinyl pyridine, vinyl Examples thereof include carbazole, vinylimidazole, vinylidene chloride homopolymer or copolymer, urethane resin, fluororesin, and natural resin. In addition, said copolymer can be used with any form of a random copolymer, a block copolymer, an alternating copolymer, and a graft copolymer.

  As the surfactant, it is preferable to contain an acetylene glycol surfactant or a polysiloxane surfactant. The acetylene glycol surfactant and the polysiloxane surfactant can improve the wettability of the recording surface of the recording medium or the like to increase the ink permeability. Examples of the acetylene glycol surfactant include 2,4,7,9-tetramethyl-5-decyne-4,7-diol, 3,6-dimethyl-4-octyne-3,6-diol, 3, Examples include 5-dimethyl-1-hexyn-3-ol, 2,4-dimethyl-5-hexyn-3-ol, and the like. Moreover, a commercial item can also be utilized for acetylene glycol-type surfactant, for example, Olphine E1010, STG, Y (above, Nissin Chemical Industry Co., Ltd. product), Surfynol 104, 82, 465, 485, TG (The above is manufactured by Air Products and Chemicals Inc.). Commercially available products can be used as the polysiloxane surfactant, and examples thereof include BYK-347, BYK-348 (above, manufactured by Big Chemie Japan Co., Ltd.) and the like. Further, the aqueous ink composition may contain other surfactants such as an anionic surfactant, a nonionic surfactant, and an amphoteric surfactant.

  Alkanediol can enhance the wettability of a recording surface such as a recording medium and improve the ink permeability. Examples of the alkanediol include 1,2-butanediol, 1,2-pentanediol, 1,2-hexanediol, 1,2-heptanediol, 1,2-octanediol, etc. , 2-alkanediol is preferred. Among these, 1,2-hexanediol, 1,2-heptanediol, and 1,2-octanediol having 6 to 8 carbon atoms are more preferable because of their particularly high permeability to recording media.

  For example, when the aqueous ink composition is applied to an inkjet recording apparatus, the polyhydric alcohol can suppress drying of the aqueous ink composition and prevent clogging of the aqueous ink composition in the inkjet recording head portion. Examples of the polyhydric alcohol 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. And trimethylolpropane.

  Examples of the pH adjuster include potassium dihydrogen phosphate, disodium hydrogen phosphate, sodium hydroxide, lithium hydroxide, potassium hydroxide, ammonia, diethanolamine, triethanolamine, triisopropanolamine, potassium carbonate, sodium carbonate, Examples thereof include sodium hydrogen carbonate.

  In addition, the water-based ink composition according to the present embodiment includes a fixing agent such as a water-soluble rosin, an antifungal agent / preservative such as sodium benzoate, an antioxidant / ultraviolet absorber such as an allophanate, a chelating agent, and an oxygen absorbing agent. An additive such as an agent can be contained. These additives can be used alone or in combination of two or more.

  The use of the water-based ink composition according to the present embodiment is not particularly limited, and can be applied to, for example, a writing instrument, a stamp, a recorder, a pen plotter, and an ink jet recording apparatus.

  The viscosity at 20 ° C. of the aqueous ink composition according to the present embodiment is preferably 2 mPa · s or more and 10 mPa · s or less, and more preferably 3 mPa · s or more and 5 mPa · s or less. When the viscosity of the aqueous ink composition at 20 ° C. is within the above range, an appropriate amount of the aqueous ink composition is ejected from the nozzle, and the flight bending and scattering of the aqueous ink composition can be further reduced. It can be preferably used.

4). Example 4.1. Example 1
4.1.1. Step (a)
Resin comprising cellulose acetate butyrate (butylation rate 35 to 39%, manufactured by Kanto Chemical Co., Ltd.) 3.0 mass% and diethylene glycol diethyl ether (produced by Nippon Emulsifier Co., Ltd.) 97 mass% on a PET film having a thickness of 100 μm The layer coating solution was uniformly applied by a bar coating method and dried at 60 ° C. for 10 minutes to form a resin layer thin film on the PET film. Subsequently, an aluminum vapor deposition layer having an average film thickness of 20 nm was formed on the resin layer using a vacuum vapor deposition device (“VE-1010 type vacuum vapor deposition device”, manufactured by Vacuum Device Co., Ltd.). Next, the laminate formed by the above method is subjected to peeling, miniaturization, and dispersion treatment simultaneously in diethylene glycol diethyl ether using a VS-150 ultrasonic disperser (manufactured by ASONE Co., Ltd.), and integrated ultrasonic dispersion An aluminum pigment dispersion having a treatment time of 12 hours was prepared. The obtained aluminum pigment dispersion was filtered through a SUS mesh filter having an opening of 5 μm to remove coarse particles. Subsequently, the filtrate was put into a round bottom flask, and diethylene glycol diethyl ether was distilled off using a rotary evaporator. Thereby, the aluminum pigment dispersion was concentrated, and then the concentration of the aluminum pigment dispersion was adjusted to obtain a 5.0 mass% aluminum pigment dispersion.

4.1.2. Step (b)
Next, 100 parts by mass of the obtained aluminum pigment dispersion was put into a beaker, to which was added 10.4 parts by mass of tetraethoxysilane (TEOS) and 2 parts by mass of 1 mol / L aqueous ammonia as a basic catalyst, Hydrolysis condensation was performed by stirring at room temperature for 7 days. Thus, an aluminum pigment dispersion containing an aluminum pigment having a silica film formed on the surface thereof was obtained.

4.1.3. Step (c)
Next, 50 parts by mass of diethylene glycol diethyl ether was put into a beaker, and phosphanol RD-720 (trade name, manufactured by Toho Chemical Co., Ltd., sodium polyoxyethylene oleyl ether phosphate) as compound (A) was added to this. By adding 12 parts by mass of POLYSTAR OM (trade name, manufactured by NOF Corporation, sodium salt of maleic anhydride-diisobutylene copolymer, Mw5000) as polymer (B) and stirring at room temperature for 1 day A clear solution was obtained. The transparent solution thus obtained was added to the previous aluminum pigment dispersion and further stirred at room temperature for 1 day.

4.1.4. Step (d)
Next, it was centrifuged (10,000 rpm, 60 minutes) to remove diethylene glycol diethyl ether contained in the aluminum pigment dispersion which was the supernatant. Thereafter, an aqueous solution containing 0.2% by mass of Polystar OM (hereinafter also referred to as “0.2% Polystar OM aqueous solution”) was added so that the concentration of the aluminum pigment was 1.7% by mass and sufficiently stirred. By doing so, a water-resistant aluminum pigment dispersion A was obtained.

4.2. Examples 2-6, Comparative Examples 1-4
Except having used what was described in Table 1 as a compound (A) and a polymer (B), it carried out similarly to said "4.1. Example 1," and water-resistant aluminum pigment dispersion liquid BJ was carried out. Obtained.

4.3. Comparative Example 5
Except that step (c) was omitted in “4.1. Example 1”, a water-resistant aluminum pigment dispersion K was obtained in the same manner as “4.1. Example 1”.

4.4. Evaluation test 4.4.1. Water resistance evaluation test 2 mL of water was put into a sample bottle, and 2 mL of any one of the obtained water-resistant aluminum pigment dispersions A to K was dropped, and the mixture was allowed to stand at a constant temperature of 25 ° C. The water resistance of the water-resistant aluminum pigment dispersion was evaluated by visually observing the change with time. The evaluation criteria for water resistance are as follows. The results of the water resistance evaluation test are also shown in Table 1.
"AAA" ... No whitening even after 160 days "AA" ... No whitening after 130 days "A" ... No whitening even after 100 days "B" ... 70 days later No whitening at the time of “C” .... No whitening after 30 days

4.4.2. Water dispersibility evaluation test Water dispersibility was evaluated by how much the water-resistant aluminum pigment dispersions A to K pass through a 20 μm filter (manufactured by MILIPORE, nylon net filter (model number: NY2004700)). Evaluation criteria for water dispersibility are as follows. The results of the water dispersibility evaluation test are also shown in Table 1.
“A”: Filter passage amount is 50 mL or more “B”: Filter passage amount is 10 mL or more and less than 50 mL “C”: Filter passage amount is less than 10 mL

4.4.3. Glossiness Evaluation One of water-resistant aluminum pigment dispersions A to K is dropped and applied to photographic paper ("PM photographic paper (glossy) model number: KA450PSK", manufactured by Seiko Epson Corporation), and 1 at room temperature. Dried for days. The gloss of the water-resistant aluminum pigment was evaluated by observing the obtained sample visually and with a scanning electron microscope (S-4700, manufactured by Hitachi High-Technologies Corporation, hereinafter also referred to as “SEM”). The evaluation criteria for the glossiness of the water-resistant aluminum pigment are as follows. The results of the gloss evaluation test are also shown in Table 1.
“A”: Good gloss (excellent metal gloss and specular gloss)
"B" ...- Slightly good gloss (excellent metal gloss but slightly matte)

4.4.5. Evaluation results Table 1 shows the results of evaluation tests of water resistance, water dispersibility, and glossiness of the water-resistant aluminum pigment dispersions obtained in Examples 1 to 6 and Comparative Examples 1 to 5.

In addition, the compound (A) and polymer (B) which were described in Table 1 are as follows, respectively.
・ "Phosphanol RD-720" (trade name, manufactured by Toho Chemical Industry Co., Ltd., polyoxyethylene oleyl ether phosphate sodium salt, HLB value = 14.4)
・ "Price Surf DB-01" (trade name, manufactured by Daiichi Kogyo Seiyaku Co., Ltd., polyoxyethylene lauryl ether phosphate monoethanolamine salt)
"Price Surf A208B" (trade name, manufactured by Daiichi Kogyo Seiyaku Co., Ltd., polyoxyethylene lauryl ether phosphate, HLB value = 6)
・ "Price Surf A208F" (trade name, manufactured by Daiichi Kogyo Seiyaku Co., Ltd., polyoxyethylene alkyl (C8) ether phosphate ester)
"Price Surf A210D" (trade name, manufactured by Daiichi Kogyo Seiyaku Co., Ltd., polyoxyethylene alkyl (C10) ether phosphate, HLB value = 6-8)
"Price Surf DBS" (trade name, manufactured by Daiichi Kogyo Seiyaku Co., Ltd., alkyl (C4) sodium phosphate ester)
"Surfinol 465" (trade name, manufactured by Nissin Chemical Industry Co., Ltd., ethylene oxide adduct of acetylene diol, HLB value = 13)
"Polystar OM" (trade name, manufactured by NOF Corporation, sodium salt of maleic anhydride-diisobutylene copolymer, Mw 5000)
・ "Demol EP" (trade name, manufactured by Kao Corporation, maleic acid-diisobutylene copolymer)
・ "Charol AN103P" (trade name, manufactured by Daiichi Kogyo Seiyaku Co., Ltd., sodium polyacrylate)
"Ceramo D-134" (trade name, manufactured by Daiichi Kogyo Seiyaku Co., Ltd., ammonium polyacrylate)

  According to Table 1, the step of adding a transparent solution in which “polyoxyethylene alkyl ether phosphate ester or salt thereof (A)” and “polymer (B) having a repeating unit derived from maleic acid” are dissolved ( The water-resistant aluminum pigment dispersions of Examples 1 to 6 obtained through c) were all excellent in water resistance, water dispersibility and glossiness. Among these, when a compound having 12 to 18 m in the general formula (1) or (2) is used as the compound (A), particularly good results were obtained.

  The obtained water resistant aluminum pigment dispersions of Example 1 and Comparative Example 5 were each dropped onto a polytetrafluoroethylene membrane filter and dried to obtain a sample for XPS measurement, and an X-ray photoelectron spectrometer ( Quantum 2000 (manufactured by ULVAC-PHI) was used, and X-ray source: monochromatic AlKα ray, analysis diameter: φ100 μm were set, and elemental analysis was performed. The results are shown in Table 2. From Table 2, the presence of C, O, Na, Si, Al, and P could be confirmed. From this, the presence of the silica film, the compound (A) and the polymer (B) can be estimated in the water-resistant aluminum pigment obtained in Example 1.

  On the other hand, in Comparative Example 1 and Comparative Example 2, another surfactant is used instead of the compound (A) in the step (c). Therefore, the polymer (B) could not be completely dissolved in diethylene glycol diethyl ether, resulting in a slightly turbid solution. Therefore, it is considered that introduction of the surfactant and the polymer (B) into the silica film formed on the surface of the aluminum pigment was insufficient. As a result, the water resistance was poor in Comparative Example 1, and the water resistance, water dispersibility, and glossiness were all poor in Comparative Example 2.

  In Comparative Example 3 and Comparative Example 4, sodium polyacrylate or ammonium polyacrylate is used in place of the polymer (B) in the step (c). Therefore, it is considered that sufficient steric hindrance effect between the water resistant aluminum pigments cannot be obtained. As a result, in Comparative Example 3 and Comparative Example 4, water dispersibility was poor, and water resistance and gloss were also poor.

  In Comparative Example 5, step (c) is omitted. Therefore, it is considered that the compound (A) was not introduced into the silica film formed on the surface of the aluminum pigment, and the introduction of the polymer (B) was insufficient. As a result, water resistance was poor and water dispersibility was slightly impaired.

4.5. Evaluation of aqueous ink composition 4.5.1. Preparation of water-based ink composition Water-resistant aluminum pigment dispersion, glycerin, trimethylolpropane, 1,2-hexanediol, orphine E1010 (acetylene glycol surfactant, manufactured by Nissin Chemical Co., Ltd.) so as to have the following composition ) And triethanolamine were mixed, and ion-exchanged water was further added so as to be 100 parts by mass, followed by mixing and stirring.

<Composition of water-based ink composition>
Water-resistant aluminum pigment dispersion (solid content) 1 part by weight Glycerin 10 parts by weight Trimethylolpropane 5 parts by weight 1,2-hexanediol 1 part by weight Orphine E1010 1 part by weight Triethanolamine 1 part by weight Ion-exchanged water Remainder Total 100 parts by weight Part As the water resistant aluminum pigment dispersion, any one of the water resistant aluminum pigment dispersions A, H, and K of Example 1, Comparative Example 2, and Comparative Example 5 was used.

4.5.2. Preparation of Evaluation Sample An ink cartridge in which the above-described aqueous ink composition was filled in a dedicated cartridge of an inkjet printer PX-G930 (manufactured by Seiko Epson Corporation) was prepared. Next, the obtained ink cartridge was attached to the black row of the inkjet printer PX-G930, and commercially available ink cartridges were attached to the other nozzle rows. A commercially available ink cartridge mounted in a place other than the black row is used as a dummy and is not used in the evaluation of this embodiment, and thus does not contribute to the effects of the present invention.

  Next, the above-described aqueous ink composition mounted in a black row is ejected onto photographic paper <glossy> (manufactured by Seiko Epson Corporation) using the above-described printer, thereby recording a solid pattern image printed thereon. I got a thing. The printing conditions were such that the weight of ink ejected per dot was 20 ng, and the resolution was 720 dpi vertically and 720 dpi horizontally.

4.5.3. Image Evaluation Method The obtained image was measured for glossiness at 60 ° using a gloss meter MULTI Gloss 268 (manufactured by Konica Minolta). The evaluation criteria for the glossiness of the obtained image are as follows. Table 3 shows the results of the glossiness evaluation test.
"A": Glossiness of 300 or more (clear metallic luster)
“B”: glossiness of 250 to less than 300 (matte metallic luster)
"C": Glossiness of 200 or more and less than 250 (no metallic luster)
“D”: measurement not possible (water-based ink composition could not be ejected)

  As shown in Table 3, the water-based ink composition produced using the water-resistant aluminum pigment dispersion of Example 1 had a glossiness of 360, and an image having a clear metallic gloss could be printed.

  On the other hand, the water-based ink compositions prepared using the water-resistant aluminum pigment dispersions of Comparative Examples 2 and 5 cannot record ink from the head of an inkjet recording apparatus, and can record an image. There wasn't. This is considered to be due to clogging of the head portion due to aggregation of the water resistant aluminum pigment in the water-based ink composition and increase in the particle size.

  The present invention is not limited to the above-described embodiments, and various modifications can be made. For example, the present invention includes substantially the same configuration (for example, a configuration having the same function, method, and result, or a configuration having the same purpose and effect) as the configuration described in the embodiment. In addition, the invention includes a configuration in which a non-essential part of the configuration described in the embodiment is replaced. In addition, the present invention includes a configuration that achieves the same effect as the configuration described in the embodiment or a configuration that can achieve the same object. In addition, the invention includes a configuration in which a known technique is added to the configuration described in the embodiment.

Claims (14)

A water-resistant aluminum pigment dispersion in which a water-resistant aluminum pigment whose surface is coated with a silica film is dispersed in an aqueous medium,
Water resistance, characterized in that polyoxyethylene alkyl ether phosphate ester or a salt thereof (A) and a polymer (B) having a repeating unit derived from maleic acid are introduced into the surface or inside of the silica film. Aluminum pigment dispersion. A step (a) of preparing an aluminum pigment dispersion in which an aluminum pigment is dispersed in an organic solvent;
Adding tetraethoxysilane to the aluminum pigment dispersion; and (b)
A step of adding a solution in which a polymer (B) having a repeating unit derived from polyoxyethylene alkyl ether phosphate ester or a salt thereof (A) and maleic acid is dissolved in an organic solvent into the aluminum pigment dispersion ( c) and
A step (d) of substituting at least a part of the organic solvent contained in the aluminum pigment dispersion with an aqueous medium;
A water-resistant aluminum pigment dispersion obtained by a method comprising:   The water-resistant aluminum pigment dispersion according to claim 2, wherein the aqueous medium is an aqueous solution to which a polymer (B) having a repeating unit derived from maleic acid is added.   The water-resistant aluminum pigment dispersion according to claim 2 or 3, further comprising adding a basic catalyst in the step (b). The water-resistant aluminum pigment dispersion according to any one of claims 1 to 4, wherein the compound (A) is a compound represented by the following general formula (1) or (2).

(In the above formula, m is an integer of 8 to 18, and n is an integer of 2 to 10. R is one selected from hydrogen, sodium, potassium and monoethanolamine, and the formula (1) And two Rs present therein may be the same or different.)   6. The aluminum pigment is a tabular grain having an average thickness of 5 nm to 30 nm and a 50% average particle diameter of 0.5 μm to 3 μm. The water-resistant aluminum pigment dispersion described in 1. The polymer (B) is at least one of repeating units represented by the following general formulas (3) and (4), and at least one of the repeating units represented by the following general formulas (5) and (6): The water-resistant aluminum pigment dispersion according to any one of claims 1 to 6, which is a copolymer having a water content.

(In the formula, A ₁ and A ₂ each independently represent hydrogen, an alkali metal, or ammonium.)

  An aqueous ink composition comprising the water-resistant aluminum pigment dispersion according to any one of claims 1 to 7. A step (a) of preparing an aluminum pigment dispersion in which an aluminum pigment is dispersed in an organic solvent;
Adding tetraethoxysilane to the aluminum pigment dispersion; and (b)
A step of adding a solution in which a polymer (B) having a repeating unit derived from polyoxyethylene alkyl ether phosphate ester or a salt thereof (A) and maleic acid is dissolved in an organic solvent into the aluminum pigment dispersion ( c) and
A step (d) of substituting at least a part of the organic solvent contained in the aluminum pigment dispersion with an aqueous medium;
A method for producing a water-resistant aluminum pigment dispersion comprising:   The method for producing a water resistant aluminum pigment dispersion according to claim 11, wherein the aqueous medium is an aqueous solution to which a polymer (B) having a repeating unit derived from maleic acid is added.   The method for producing a water-resistant aluminum pigment dispersion according to claim 9 or 10, further comprising adding a basic catalyst in the step (b). The method for producing a water-resistant aluminum pigment dispersion according to any one of claims 9 to 11, wherein the compound (A) is a compound represented by the following general formula (1) or (2).

(In the above formula, m is an integer of 8 to 18, and n is an integer of 2 to 10. R is one selected from hydrogen, sodium, potassium and monoethanolamine, and the formula (1) And two Rs present therein may be the same or different.)   The aluminum pigment is a tabular particle having an average thickness of 5 nm to 30 nm and a 50% average particle diameter of 0.5 μm to 3 μm. A method for producing a water-resistant aluminum pigment dispersion described in 1. The polymer (B) is at least one of repeating units represented by the following general formulas (3) and (4), and at least one of the repeating units represented by the following general formulas (5) and (6): The method for producing a water-resistant aluminum pigment dispersion according to any one of claims 9 to 13, which is a copolymer having water.

(In the formula, A ₁ and A ₂ each independently represent hydrogen, an alkali metal, or ammonium.)