JP2010209333A - Composite pigment material and composite pigment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a composite pigment material using a metal or a metal compound having the excellent storage stability without a problem of reaction with water, and a composite pigment as an aqueous ink composition for ink jet, capable of maintaining dispersion stability in an aqueous system with the excellent printing quality and storage stability, and a quick-drying property for obtaining a recorded matter with the excellent water resistance, light resistance and glossiness. <P>SOLUTION: The composite pigment material has a structure with a resin layer and a pigment layer laminated successively onto a sheet-like substrate. The pigment layer has a structure with a silicon oxide layer, a metal or metal compound layer, and a silicon oxide layer laminated successively. The pigment layer of the composite pigment material is peeled off from the sheet-like substrate from the boundary with the resin layer so as to be pulverized. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a composite pigment base and a composite pigment. More specifically, the present invention relates to a composite pigment base and a composite pigment used in an ink jet recording ink excellent in storage stability and dispersibility.

  The ink jet recording method is a method of recording characters and figures on the surface of a recording medium such as paper by discharging ink droplets from a fine nozzle head. As an ink jet recording method, an electric signal is converted into a mechanical signal using an electrostrictive element, and ink droplets stored in the nozzle head portion are intermittently ejected to record characters and symbols on the surface of the recording medium, or A part of the ink liquid is rapidly heated at a part near the ejection part of the nozzle head to generate bubbles, and ink droplets are intermittently ejected by the volume expansion caused by the bubbles, and characters and symbols are printed on the surface of the recording medium. A method for recording the image has been put into practical use.

  Recently, water-based pigment inks in which pigments are dispersed in water have been provided as inks for inkjet recording. This is because the ink using the pigment has the characteristics that the obtained printed image is superior in water resistance and light resistance as compared with the ink using the water-soluble dye. In such a water-based pigment ink, it is generally performed to disperse a pigment in an aqueous dispersion medium using a dispersant such as a surfactant or a polymer dispersant. However, in such a case, it is recognized that the dispersing agent only adsorbed on the pigment surface may lower the dispersion state by repeating desorption and adsorption.

  For the purpose of improving the dispersibility of the pigment contained in the ink for ink jet recording, a technique using a microencapsulated pigment in which colorant particles are coated with a polymer is known. For example, in the presence of a polymeric azo initiator containing a specific repeating unit and a vinyl polymerizable dispersant, the water-insoluble colorant is dispersed under conditions where the polymeric azo initiator is not activated, In the obtained dispersion, a microencapsulated colorant dispersion and a water-based ink containing a microencapsulated colorant obtained by activating the polymer azo initiator to polymerize the vinyl polymerizable dispersant The composition is disclosed (for example, refer patent document 1).

In the inkjet recording ink, a pigment made of a metal such as aluminum having a metal color such as silver (hereinafter also referred to as a metal pigment) may be used.
However, metal pigments have limitations in terms of use, such as low gloss due to surface unevenness, and need to be stored in an inert gas atmosphere avoiding contact with moisture and the like. Furthermore, the reactivity with water is also high, and there has been a problem in storage stability such as deterioration of quality due to hydrogen generation or gelation during long-term storage.

Pigments (colorant particles) using a highly active metal such as aluminum easily react with moisture in aqueous solvents, causing problems such as generation of hydrogen and gelation during storage. Conventionally, non-aqueous solvent-based inks have been used.
Further, when storing conventional metal pigments and inks, paints, and the like containing metal pigments, there are problems of reactivity with water and surface oxidation, and long-term storage is impossible.
In addition, conventional metal pigments usually have a large particle size of 20 to 30 μm, and as such cannot be used for inkjet inks.
Furthermore, in addition to the size of the above particle size, due to its specific gravity, the dispersion stability is poor and sediments immediately. Therefore, even when the microencapsulation technology of Patent Document 1 is used, the dispersion stability cannot be sufficiently improved.

  On the other hand, an ink-jet ink containing a piece of a laminate having a metal vapor-deposited layer and a resin layer is disclosed in order to impart a metallic luster glitter decoration or the like to an image obtained by the ink-jet ink (see, for example, Patent Document 2). .) However, the technique of Patent Document 2 cannot overcome the problem of reactivity with water.

JP 2003-113327 A Japanese Patent Laid-Open No. 11-343436

Accordingly, an object of the present invention is to solve the above-mentioned problems, and to provide a composite pigment base material using a metal or a metal compound, which has excellent storage stability and does not have a problem of reactivity with water. It is.
Furthermore, as a water-based ink composition for inkjet, it is possible to maintain dispersion stability in an aqueous system, and to obtain a recorded matter having excellent printing quality and storage stability, and excellent water resistance, light resistance, and glossiness. It is to provide a composite pigment that can be used.

  The present inventor has found that conventional metal pigments are highly reactive in the form of fine powder, and have problems with storage stability and reactivity with water, but the structure is a laminated structure of silicon oxide layer / metal pigment layer / silicon oxide layer. The composite pigment is chemically stable, has no reactivity with water, has a significantly improved long-term storage stability, and has been found to be excellent in quality as a water-based ink composition for inkjet. It is what.

That is, the present invention is achieved by the following configuration.
(1) It has a structure in which a resin layer and a pigment layer are sequentially laminated on a sheet-like substrate surface, and the pigment layer has a structure in which a silicon oxide layer, a metal or metal compound layer, and a silicon oxide layer are sequentially laminated. A composite pigment base material.
(2) The composite pigment base material according to (1), wherein the pigment layer has a thickness of 100 to 500 nm.
(3) The composite pigment base material according to (1), wherein the resin layer is made of polyvinyl alcohol, polyethylene glycol, polyacrylic acid, polyacrylamide, or a cellulose derivative.
(4) The composite pigment base material according to (1), wherein the silicon oxide layer is formed from silicon alkoxide or a polymer thereof by a sol-gel method.
(5) The composite pigment base material according to (1), wherein the metal or metal compound layer is formed by vacuum deposition, ion plating, or sputtering.
(6) The composite pigment base material according to (1), wherein the sheet-like substrate is polyethylene terephthalate or a copolymer thereof.
(7) The composite pigment base material according to the above (1), which has a plurality of sequentially laminated structures of the resin layer and the pigment layer.
(8) The composite pigment base material according to (7), wherein the total thickness of the laminated structure of the plurality of pigment layers is 5000 nm or less.

(9) A composite pigment obtained by peeling and pulverizing the pigment layer of the composite pigment base material according to (1) from the sheet-like substrate with the resin layer as a boundary.
(10) The composite pigment according to (9), wherein the peeling is performed by immersing the composite pigment base material in a liquid.
(11) The composite pigment according to (9), wherein the pulverization is performed by ultrasonic treatment.
(12) A composite pigment obtained by subjecting the composite pigment base described in (1) to ultrasonic treatment while being immersed in a liquid.
(13) The composite pigment according to (10) or (12), wherein the liquid is aqueous.

According to the present invention, it is possible to obtain a composite pigment base material using a metal or a metal compound, which has excellent storage stability that could not be obtained by conventional techniques and does not have a problem of reactivity with water.
That is, since the composite pigment base material of the present invention is a laminated structure in which the metal pigment layer is surrounded by the silicon oxide layer, the influence on oxygen and water is reduced.
Moreover, the composite pigment base material of the present invention can be obtained, for example, by subjecting it to ultrasonic treatment while being immersed in a liquid to obtain a composite pigment having an average particle size of about 3 μm.

In addition, as a water-based ink composition for inkjet, the silicon oxide has a small specific gravity and polyvinyl alcohol or the like of the resin layer serves as a protective colloid, and can improve dispersion stability in an aqueous system. ), Improved print quality and storage stability, quick drying, and excellent water resistance, light resistance, and glossiness. Can be provided.
In addition, by storing the composite pigment base material of the present invention in a roll shape, it becomes possible to further suppress contact with oxygen and moisture in the air, which has been difficult for conventional metal pigments for one year. Long-term storage exceeding 1 is possible.

Since the composite pigment base material of the present invention is a laminated structure in which the metal pigment layer is surrounded by the silicon oxide layer, the influence on oxygen and water can be reduced, and the storage stability that could not be obtained by the conventional technology It is possible to provide a metal composite pigment base material which is excellent in water resistance and has no problem of reactivity with water.
In addition, the composite pigment of the present invention peeled from the composite pigment base can prevent reactivity with water because the metal pigment layer is protected by a silicon oxide layer as an ink-jet aqueous ink composition. The specific gravity is small, it can be used even in aqueous solvents, and the resin layer has a role of protective colloid, can improve dispersion stability in aqueous systems, and can be used with a recording medium (such as paper). Provided is a composite pigment having improved adhesion, excellent print quality and storage stability, quick drying, and capable of obtaining a recorded product with excellent water resistance, light resistance and gloss. There is an effect.

Hereinafter, the composite pigment base material and the composite pigment of the present invention will be described in detail.
The composite pigment base material of the present invention has a structure in which a resin layer and a pigment layer are sequentially laminated on one side or both sides of a sheet-like substrate surface, and the pigment layer is a silicon oxide layer, a metal or metal compound layer. The composite pigment of the present invention is a pigment obtained by separating the pigment layer of the composite pigment base material from the sheet-like base material with the resin layer as a boundary and pulverizing it. is there.
That is, although the composite pigment of the present invention is a metal or metal compound pigment, it improves the drawbacks of conventional metal pigments, particularly storage stability, and is also excellent as an aqueous ink composition for inkjet, particularly dispersion stability. Therefore, the metal pigment has a laminated plate-like structure in which a silicon oxide layer / metal or a metal compound layer / silicon oxide layer is sequentially laminated.
Hereinafter, the component of each layer constituting the composite pigment base material and the composite pigment of the present invention, a method for forming the layer, a treatment method, and the like will be described.

(Pigment layer)
The pigment layer in the laminated plate-like structure of the composite pigment base material of the present invention will be described.
The pigment layer of the present invention has a structure in which a silicon oxide layer, a metal or metal compound layer, and a silicon oxide layer are sequentially laminated.
The thickness of the pigment layer is preferably in the range of 100 to 500 nm. If it is less than 100 nm, the mechanical strength is insufficient, and if it exceeds 500 nm, the strength becomes too high, so that pulverization / dispersion becomes difficult.

First, the metal or metal compound layer in the pigment layer is not particularly limited as long as it has a function such as having a metallic luster, but aluminum, silver, gold, nickel, chromium, tin, zinc, indium Titanium or the like is used, and at least one of these simple metals, metal compounds, alloys thereof and mixtures thereof is used.
The metal or metal compound layer is preferably formed by vacuum deposition, ion plating or sputtering. The thickness of these metal or metal compound layers is not particularly limited, but is preferably in the range of 30 to 150 nm. If it is less than 30 nm, it is inferior in reflectivity and glitter, and the performance as a metal pigment is lowered. If it exceeds 150 nm, the apparent specific gravity increases, and the dispersion stability of the composite pigment decreases. Unnecessary increase of the metal or metal compound layer only increases the weight of the particles, and even if the film thickness is larger than this, the reflectivity and glitter are not changed so much.

The silicon oxide layer in the pigment layer is not particularly limited as long as it is a layer containing silicon oxide, but is preferably formed from silicon alkoxide or a polymer thereof by a sol-gel method.
The silicon oxide layer is formed by applying an alcohol solution in which the silicon alkoxide or a polymer thereof is dissolved and baking it.
The silicon oxide layer is applied by commonly used gravure coating, roll coating, blade coating, extrusion coating, dip coating, spin coating, or the like. After coating and drying, the surface is smoothed by calendaring if necessary.

  Although the thickness of a silicon oxide layer is not specifically limited, The range of 50-150 nm is preferable. 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 metal or metal compound layer.

[Resin layer]
The resin layer in the present invention is an undercoat layer of the pigment layer, but is a peelable layer for improving the peelability from the sheet-like substrate surface. Accordingly, the resin is not particularly limited as long as it is a hydrophilic resin. For example, polyvinyl alcohol, polyethylene glycol, polyacrylic acid, polyacrylamide, or a cellulose derivative is preferable.
A layer is formed by applying an aqueous solution of one or more of the above hydrophilic resins and drying. The coating solution can contain additives such as a viscosity modifier.
The resin layer is applied in the same manner as the silicon oxide layer.

  Although the thickness of a resin layer is not specifically limited, 0.5-50 micrometers is preferable, More preferably, it is 1-10 micrometers. 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 silicon oxide layer.

The composite pigment base material of the present invention may have a layer structure having a plurality of sequential laminated structures of the resin layer and the pigment layer. At that time, the total thickness of the laminated structure of a plurality of pigment layers, that is, the thickness of the pigment layer-resin layer-pigment layer ... resin layer-pigment layer, excluding the sheet-like substrate and the resin layer immediately above it, It is preferable that it is 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. In addition, when pigmented, it is excellent in glitter and preferable.
Moreover, although the structure where the resin layer and the pigment layer were laminated | stacked in order on both surfaces of the sheet-like base material surface is mentioned, it is not limited to these.

[Sheet substrate]
Although it does not specifically limit as a sheet-like base material used for the composite pigment raw material of this invention, Polyester film, such as polytetrafluoroethylene, polyethylene, a polypropylene, a polyethylene terephthalate, a polyethylene naphthalate, 66 nylon, 6 nylon, etc. Release films such as polyamide film, polycarbonate film, triacetate film, polyimide film, and the like can be mentioned.
A preferable sheet-like substrate is polyethylene terephthalate or a copolymer thereof.
Although the thickness of these sheet-like base materials is not specifically limited, 10-150 micrometers is preferable. 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 and the like.

[Removal treatment of composite pigment]
The composite pigment of the present invention can be obtained by peeling the pigment layer of the composite pigment base material from the sheet-like base material with the resin layer as a boundary, pulverizing and refining.
The release treatment method of the composite pigment is not particularly limited, but is a method in which the composite pigment raw material is immersed in a liquid, or 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. Further, the liquid is preferably an aqueous system.
The composite pigment of the present invention can be used in an aqueous solvent because the metal pigment layer is protected by the silicon oxide layer, and the resin layer has a role of a protective colloid, and is dispersed in water. It is possible to obtain a stable aqueous dispersion only by performing the step. In addition, when the composite pigment of the present invention is used in an ink composition, the resin layer also has a function of imparting adhesiveness to a recording medium such as paper.

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

[Example 1]
<Preparation of base sheet>
On a PET film having a thickness of 100 μm, a coating liquid having the following composition was applied and dried by a spin coating method to form a resin layer.

(Resin layer coating solution)
PVA (polyvinyl alcohol, average molecular weight 10,000, saponification degree 80%)
3.3 wt%
Glycerol 1.7wt%
Ion exchange water

(Resin layer coating conditions)
Coating condition: Rotated at 500 rpm for 5 seconds, then rotated at 2000 rpm for 30 seconds Drying condition: 100 ° C., 5 minutes The thickness of the resin layer formed under these conditions was 10 μm.

<Formation of silicon oxide layer>
On the PET film treated by the above method, a coating liquid having the following composition was applied and baked by a spin coating method to form a silicon oxide layer.

(Silicon oxide layer coating solution)
HAS-6 (manufactured by Colcoat Co., Ltd.) 10 wt%
Ethanol 42.5wt%
2-Ethoxyethanol 47.5wt%

(Silicon oxide layer coating conditions)
Coating condition: Rotated at 500 rpm for 5 seconds, then rotated at 2000 rpm for 30 seconds Firing condition: 140 ° C., 5 minutes The thickness of the silicon oxide layer formed under these conditions was 70 nm.

<Formation of aluminum layer>
An aluminum vapor deposition layer having a film thickness of 70 nm was formed on the silicon oxide layer using the following apparatus.
Apparatus: Vacuum device, VE-1010 type vacuum evaporation system

<Formation of silicon oxide layer>
Similar to the above method, a silicon oxide layer was formed on the aluminum layer. The thickness of the formed silicon oxide layer was 70 nm.

<Storage stability>
In order to investigate the preservability of a PET film (pigment base) having a silicon oxide-aluminum-silicon oxide laminate formed by the above method, the pigment base is wound around a 4-inch diameter paper tube, and the atmosphere The sample was allowed to stand for 1 year at room temperature and pressure. As a result, even after one year, the pigment base material did not show a decrease in surface gloss due to oxidation or corrosion. In addition, even when the pigment raw material after standing is used as a coating solution by the pigmentation process shown below, the metallic luster of the coating film obtained by dripping on the PM / MC photographic paper can be stored for one year. It showed the same metallic luster as the untreated pigment base.

<Peeling treatment and pigmentation process>
A composite aluminum pigment formed by the above-described method, and simultaneously removing, refining and dispersing a PET film having a resin layer-silicon oxide-aluminum-silicon oxide laminate in ion-exchanged water using an ultrasonic disperser. A dispersion was prepared.

  The dispersion was centrifuged using a centrifuge under the following conditions to precipitate the pigment and separate it. Thereafter, it was naturally dried at room temperature to obtain a composite aluminum pigment.

  Centrifugal conditions: 10000 rpm x 30 min

  The composite aluminum pigment obtained above was applied as a 20 wt% coating solution as described below, and dropped onto PM / MC photographic paper (manufactured by Seiko Epson, model number KA420MSH). It was confirmed that it was obtained.

<Composite aluminum pigment coating solution>
Composite aluminum pigment 20.0wt%
PVA (polyvinyl alcohol, average molecular weight 10,000, saponification degree 80%)
5.0wt%
Ethanol 10.0wt%
Glycerin 10.0wt%
Ion exchange water

  Even after the coating solution was stored at room temperature and normal pressure for 6 months, no hydrogen generation or gelation of the coating solution was observed, and the precipitated pigment could be redispersed by stirring for several minutes. And when it was dripped on PM / MC photographic paper (the Seiko Epson make, model number KA420MSH) like last time, it was confirmed that the coating film which has silver gloss is obtained.

Claims (13)

  A composite having a structure in which a resin layer and a pigment layer are sequentially laminated on a sheet-like substrate surface, and the pigment layer has a structure in which a silicon oxide layer, a metal or metal compound layer, and a silicon oxide layer are sequentially laminated. The active ingredient of pigment.   The composite pigment base material according to claim 1, wherein the pigment layer has a thickness of 100 to 500 nm.   The composite pigment base material according to claim 1, wherein the resin layer is made of polyvinyl alcohol, polyethylene glycol, polyacrylic acid, polyacrylamide, or a cellulose derivative.   The composite pigment base material according to claim 1, wherein the silicon oxide layer is formed from silicon alkoxide or a polymer thereof by a sol-gel method.   The composite pigment base material according to claim 1, wherein the metal or metal compound layer is formed by vacuum deposition, ion plating, or sputtering.   The composite pigment base material according to claim 1, wherein the sheet-like substrate is polyethylene terephthalate or a copolymer thereof.   The composite pigment base material according to claim 1, wherein the composite pigment base material has a plurality of sequentially laminated structures of the resin layer and the pigment layer.   The composite pigment base material according to claim 7, wherein the total thickness of the laminated structure of the plurality of pigment layers is 5000 nm or less.   The composite pigment which peeled and pulverized the said pigment layer of the composite pigment raw material of Claim 1 from the said sheet-like base material on the said resin layer as a boundary.   The composite pigment according to claim 9, wherein the peeling is performed by immersing the composite pigment base material in a liquid.   The composite pigment according to claim 9, wherein the pulverization is performed by ultrasonic treatment.   A composite pigment obtained by sonicating the composite pigment base material according to claim 1 while being immersed in a liquid.   The composite pigment according to claim 10 or 12, wherein the liquid is aqueous.