JP2011153208A - Ink produced by using pearlescent pigment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pearlescent ink having increased brightness of reflected light. <P>SOLUTION: The ink produced by using a pearlescent pigment is a coating liquid comprising the pearlescent pigment and a binder, wherein the pearlescent pigment is produced by applying a metallic compound to a flaky substrate of the pigment comprising at least either one of mica, synthetic mica, alumina, silica, aluminum, borosilicate glass, talc and kaolin, the refractive index of the pearlescent pigment is set to be smaller than the refractive index of the binder, the refractive index difference of the pearlescent pigment and the binder is ≥1.0, and the refractive index of the pearlescent pigment is ≥1.9. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a printing ink excellent in glitter, and particularly relates to an ink that improves the color development of a pearlescent pigment.

  Pearl luster ink has color tone and gloss that cannot be expressed by conventional process color printing ink, etc., and because of its design, it is used not only in printing ink but also in many fields such as automobile paint, building material paint, various plastics, etc. ing.

  Pearlescent ink is characterized by a visual effect due to the different colors of shade and highlight, but the conventional ink composition lacks the glossiness due to the poor color of reflected light, so that sufficient pearly luster is obtained. I couldn't. As means for improving pearl luster, there are methods such as thickening the coating film, increasing the pearl luster pigment concentration, and increasing the particle size of the pearl luster pigment, but it is difficult to realize depending on the printing method such as offset printing. There were restrictions.

  Patent Document 1 discloses an offset printing ink that exhibits good pearly luster even at a low pigment concentration by adjusting the ink composition, viscosity, and printing conditions. However, the degree of color development of pearlescent ink, which is characterized by soft gloss, is limited, and it has been difficult to express strong brightness and vivid color development.

  Patent Document 2 discloses a pearlescent ink that uses glass as a scaly base material for a pearlescent pigment and exhibits a brightness feeling stronger than that of a pearlescent ink of a mica base material, but is limited to the case where the base material is glass. This technology cannot be applied with pearlescent pigments of other base materials.

JP-A-7-34021 JP 2001-262036 A

  The present invention has been made in view of the above prior art, and a problem to be solved is to provide an ink using a pearlescent pigment having a high reflected light brightness.

In order to solve the above-mentioned problem, as the invention according to claim 1, in a coating liquid comprising at least a pearlescent pigment having a thin plate-like substrate coated with a metal compound and a binder,
It is an ink using a pearlescent pigment characterized in that the refractive index of the binder is smaller than the refractive index of the pearlescent pigment, and the difference between the refractive index of the pearlescent pigment and the refractive index of the binder is 1.0 or more. .

  The invention according to claim 2 is characterized in that any one of mica, synthetic mica, alumina, silica, aluminum, borosilicate glass, talc, and kaolin is used as the thin plate-like substrate of the pearl luster pigment. An ink using the pearl luster pigment according to claim 1.

  In the invention according to claim 3, the metal compound coated on the thin plate-like substrate of the pearlescent pigment is titanium dioxide, or ferric oxide, zirconium dioxide, antimony trisulfide, lead oxide, selenization. Zinc, cadmium sulfide, bismuth oxychloride, lead chloride, ceria, tantalum pentoxide, zinc sulfide, zinc oxide, cadmium oxide, neodymium oxide, antimony trioxide, indium oxide, silica, alumina, or tin oxide. The ink using the pearl luster pigment according to claim 1, wherein the ink is multi-layered with two or more layers.

  The invention according to claim 4 is the ink using the pearlescent pigment according to any one of claims 1 to 3, wherein the pearlescent pigment has a refractive index of 1.9 or more.

  By making the refractive index of the binder smaller than the refractive index of the pearlescent pigment, the difference in refractive index increases, the amount of reflected light at the boundary between the binder and the pearlescent pigment increases, and the brightness of the interference light increases. Ink using pearlescent pigments that can provide strong pearly luster and have high transparency and high reflectivity, resulting in deepness due to repeated reflection and transmission, and a strong radiance. Can be provided.

It is the structure schematic of the pearl luster pigment and binder of one Example in this invention. FIG. 6 is a schematic diagram of the trajectory of the light path when the observation surface side A is oblique.

  FIG. 1 shows a schematic diagram of the configuration of the pearlescent pigment and binder of the present invention.

  Hereinafter, preferred embodiments of ink using the pearlescent pigment according to the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a schematic diagram of a pearlescent pigment and a binder according to an embodiment of the present invention. Ink 1 using a pearlescent pigment is composed of a pearlescent pigment 2, a binder 30, and an organic solvent. The pearlescent pigment 2 is formed by coating the surface of a low refractive index thin plate-like substrate 10 with a metal compound 20 having a high refractive index.

  FIG. 2 shows a light path when the observation surface side A is oblique, and the incident light is reflected at the boundary between the binder 30 and the metal compound 20, and between the metal compound 20 and the thin plate-like substrate 10. Reflect at the boundary. Because there is a difference in the path difference, interference occurs, and a specific interference color is shown depending on the thickness of the metal compound 20.

  The thin plate substrate 10 is highly transparent, scaly, and has a low refractive index.

  As the material for the thin plate-like substrate, mica, synthetic mica, alumina, silica, aluminum, borosilicate glass, talc, kaolin, and the like are preferable, and mica, synthetic mica, alumina, silica, and aluminum are particularly preferable.

  The characteristics when the material of the thin plate-like substrate is used are as follows.

  First, the mica has a refractive index of 1.58, is nearly colorless and transparent, has excellent particle cleaving properties, and obtains flake particles. However, the mica contains a small amount of iron and becomes iron oxide by firing, so it is slightly yellowish and the yellowness may be noticeable depending on the color.

  The synthetic mica is a highly transparent thin plate-like substrate in which dullness and turbidity are eliminated by removing impurities such as iron contained in the mica.

  Further, the silica is a thin plate-like substrate that can obtain a strong gloss without dullness because its refractive index is 1.45, which is lower than that of mica, and is very transparent.

  The alumina has a high refractive index of 1.78, but since it has high transparency and excellent surface smoothness, it has a strong glitter, so even if the refractive index difference from the metal compound is small, It is a thin plate-like substrate capable of obtaining a bright color as compared with a pearlescent pigment of a normal mica substrate.

  Moreover, since the borosilicate glass has a low refractive index of 1.47 and high transparency, a strong luminance can be obtained. In addition, since it has high hardness and excellent heat resistance, it is a very stable thin plate-like substrate.

  The talc has a refractive index of 1.57, which is about the same as mica, but the surface smoothness of the particles is poor and the cleavage property is poor, so that an unexfoliated portion remains at the end, thereby scattering light. Increases and interference light is weak.

  The kaolin is a white natural mineral having a refractive index of 1.55. Because it has water absorption and adsorptivity, it was used alone for baby powder. Furthermore, it is used in cosmetics such as foundations by giving a pearly luster by coating a metal compound.

  Unlike the above-mentioned materials, aluminum does not transmit light, but since there are many reflections from the interface between the metal compound 20 and aluminum, an interference color with strong luminance can be obtained, so it can be used as a thin plate. Is possible.

  In the shape of the thin plate-like substrate, the average equivalent diameter of the thin plate-like substrate 10 is preferably 5 μm or more and 500 μm or less, the average thickness is 0.1 μm or more and 5 μm or less, and the aspect ratio is 5 or more and 300 or less. . A smooth gloss can be expressed with a small particle size, and a sparkling radiant shine can be expressed with a large particle size.

  As the metal compound 20 used as a covering material for covering the thin plate-like substrate, one having a higher refractive index than that of the thin plate-like substrate 10 is used in order to improve the glitter of the pearlescent ink.

Examples of the metal compound 20 include rutile type titanium oxide (refractive index: 2.71), anatase type titanium dioxide (refractive index: about 2.52), ferric oxide (refractive index: about 3.01), zirconium dioxide. (Refractive index: about 2.23), lead oxide (refractive index: 2.42), zinc selenide (refractive index: 2.40), cadmium sulfide (refractive index: 2.5), bismuth oxychloride (refractive index) : 2.15), tantalum pentoxide (refractive index: 2.20), zinc sulfide (refractive index: 2.37), zinc oxide (refractive index: 1.95), cadmium oxide (refractive index: 2.49) Indium oxide (refractive index: 1.95), silica (refractive index: 1.45), alumina (refractive index: 1.78), tin oxide (refractive index: 1.9), preferably rutile titanium oxide Anatase type titanium dioxide, ferric oxide, especially weather resistance Rutile titanium dioxide from and cost is desired. Either of these is used to coat a single layer or two or more types.
In addition, as long as it is a metal compound whose refractive index exists in the range of 1.9 or more and 3.1 or less, you may be other than the said metal compound.

  When these metal compounds are coated on a thin plate-like substrate, the value becomes smaller than the refractive index of the single crystal. For example, rutile type titanium oxide (refractive index: 2.5), anatase type titanium dioxide (refractive index: about 2.3). ), Ferric oxide (refractive index: about 2.9) and about 0.2 lower than the single crystal.

  Further, in the titanium dioxide, the coating thickness is preferably in the range of 0.02 μm or more and 0.7 μm or less, and has no interference color at 0.02 μm or less or 0.7 μm or more. When the coating thickness increases, the color of the interference light changes from silver, gold, red, purple, blue, and green. When the coating thickness is further increased, the color development is reproduced in the same order from the interference of the golden color.

  Since ferric oxide has a very high refractive index of 3.01, it has a feature that the reflectance of the pigment surface is high and strong luminance can be obtained. On the other hand, since it is reddish, when the flaky substrate is coated alone, it has interference colors of gold, orange, and red as the coating thickness changes. Further, it is often used for the purpose of changing the reflection color by being laminated on the surface of the titanium dioxide coating layer.

  The coating thickness of the metal compound varies depending on the type of the metal compound, the required glitter, the desired interference color, etc., but the coating layer thickness is 0.01 to 1 μm, particularly 0.02 to 0.7 μm. It is preferable to do so. If the coating thickness is excessively thin, sufficient gloss cannot be obtained, and if it is excessively thick, economic efficiency is impaired.

  When the coating thickness of the metal compound is changed, the reflected light and the transmitted light gradually change from an achromatic color to various chromatic colors as the coating thickness increases. For example, in the thin plate-like substrate coated with rutile type titanium dioxide, when the thickness of the titanium dioxide coating is around 0.05 μm, both the reflected light and the transmitted light are silver, but the coating thickness is increased to about 0. When the thickness is .14 μm, the reflected light is magenta and the transmitted light is blue-green, and when the coating thickness is about 0.2 μm, the reflected light is yellow-green and the transmitted light is changed to red. Although the hue of these reflected light and transmitted light is caused by the light interference phenomenon, light scattering can be prevented if the surface of the thin plate-like substrate is extremely smooth, so that the thin plate-like substrate having irregularities on the surface By coating the material with titanium dioxide, clear and strong glitter can be obtained.

  Next, as a ratio of the pearlescent pigment in the ink using the pearlescent pigment, if the content of the pearlescent pigment in the ink using the pearlescent pigment is excessively small, sufficient glitter cannot be obtained, If the amount is excessively large, the viscosity becomes high and it becomes difficult to redisperse the pearlescent pigment, and the fluidity of the ink using the pearlescent pigment is impaired. Therefore, 0.1 part by weight or more in the ink using the pearlescent pigment. It is preferable to be within the range of 50 parts by weight or less. In particular, in order to maintain the viscosity, color tone, and glitter of the ink using the pearlescent pigment, it is preferably used in the range of 1 to 40 parts by weight in the ink using the pearlescent pigment.

  Next, the binder 30 according to the present invention will be described below. The binder is contained in order to fix the pearl luster pigment to the printed material and to disperse it uniformly.

  As the binder, polyester resin (refractive index: 1.58), acrylic resin (refractive index: 1.50), fluorene resin (refractive index: 1.60), phenol resin (refractive index: 1.70), acetic acid Vinyl (refractive index: 1.46), vinyl chloride (refractive index: 1.54), polycarbonate resin (refractive index: 1.58), polyamide resin (refractive index 1.53), polyvinylidene chloride (refractive index: 1) .61), resins such as melamine resin (refractive index: 1.60) fluororesin (refractive index: 1.35), silicone resin (refractive index: 1.45), etc., and these resins are used alone. Alternatively, two or more kinds may be mixed and used.

  In the present invention, a low refractive index binder is used, and it is desirable that the refractive index of the pearlescent pigment be 1.0 or less. If the difference in refractive index is less than 1.0, the brightness of reflected light becomes small, and the resulting ink layer will have poor glitter.

  (1) Fluorine resin or silicone resin is used as the low refractive index binder. (2) Fluorine resin or fluorine-containing acrylic resin or silicone resin of 0.7 μm or more and 5.0 μm or less is relatively used as a polyester resin or acrylic resin. (3) Mixing low-refractive-index particles such as colloidal silica having an average particle diameter of 2 nm or more and 100 nm or less into a polyester resin or an acrylic resin.

  The proportion of the binder in the ink using the pearlescent pigment is preferably 5 parts by weight or more and 50 parts by weight or less, and if the binder content is less than 5 parts by weight, the pearly powder is not sufficiently fixed to the printing material. When the amount exceeds 50 parts by weight, the viscosity becomes excessively high, and the fluidity of the ink using the pearlescent pigment is lowered, resulting in poor printability.

  Next, the organic solvent according to the present invention will be described below.

  As an organic solvent, it is used as a dispersion solvent for pearlescent pigments. Examples include aliphatic hydrocarbons such as n-hexane and n-heptane, aromatic hydrocarbons such as toluene and xylene, ethyl alcohol, isopropyl alcohol, and the like. Alcohols, glycols such as ethylene glycol and diethylene glycol, esters such as ethyl acetate and isopropyl acetate, and ketones such as methyl ethyl ketone and cyclohexanone can be used. These organic solvents may be used alone or in combination of two or more.

  In addition, the content of the organic solvent in the ink using the pearlescent pigment is desirably within the range of 30 parts by weight or more and 80 parts by weight or less. When the content of the organic solvent is less than 30 parts by weight, The dispersibility is lowered, and the fluidity of the ink using the pearlescent pigment is lowered, so that printing becomes difficult. When the amount is 80 parts by weight or more, the ink using the pearlescent pigment is insufficiently dried. It becomes an appropriate defect. In addition, printing becomes difficult because the viscosity is excessively low and the fluidity is too high.

  Appropriate viscosity according to the printing method is about 100,000 mPa · s for offset printing, 1,000 to 50,000 mPa · s for silk screen printing, and 5 to 200 mPa · s for gravure printing. The viscosity may be adjusted and used.

At the same time, additives such as a dispersant for stabilizing the dispersion of the pearlescent pigment and a leveling agent for preventing the surface of the ink layer from becoming rough from the printed ink to the drying of the organic solvent are added appropriately. be able to.

  Examples of the present invention will be described below, but the present invention is not limited to these examples.

  In the adjustment examples shown below, pearl luster pigment is added to the binder to prepare each adjustment liquid.

(Adjustment example 1)
80 parts by weight of Iriodin 221 (manufactured by Merck & Co.) was added to 100 parts by weight of the fluororesin and stirred and dispersed (Preparation liquid 1).

(Adjustment example 2)
80 parts by weight of Iriodin 221 (Merck) was added to 100 parts by weight of the vinyl acetate resin, and the mixture was stirred and dispersed (Preparation liquid 2).

(Adjustment Example 3)
80 parts by weight of Iriodin 221 (manufactured by Merck) was added to 100 parts by weight of the acrylic resin, and the mixture was stirred and dispersed (Preparation liquid 3).

(Adjustment example 4)
80 parts by weight of Iriodin 221 (manufactured by Merck & Co.) was added to 100 parts by weight of the polyamide resin, and stirred and dispersed (Preparation liquid 4).

(Adjustment Example 5)
80 parts by weight of Iriodin 221 (manufactured by Merck) was added to 100 parts by weight of the vinyl chloride resin, and the mixture was stirred and dispersed (Preparation liquid 5).

(Adjustment Example 6)
80 parts by weight of Iriodin 221 (manufactured by Merck) was added to 100 parts by weight of the polyester resin, and the mixture was stirred and dispersed (Preparation liquid 6).

(Adjustment Example 7)
80 parts by weight of Iriodin 221 (Merck) was added to 100 parts by weight of the polycarbonate resin, and the mixture was stirred and dispersed (Preparation liquid 7).

(Adjustment Example 8)
80 parts by weight of Iriodin 221 (manufactured by Merck & Co.) was added to 100 parts by weight of the fluorene resin, and stirred and dispersed (Preparation liquid 8).

(Adjustment Example 9)
80 parts by weight of Iriodin 221 (manufactured by Merck & Co.) was added to 100 parts by weight of the melamine resin and stirred and dispersed (Preparation liquid 9).

(Adjustment Example 10)
80 parts by weight of Iriodin 221 (manufactured by Merck & Co.) was added to 100 parts by weight of the phenol resin, and the mixture was stirred and dispersed (Preparation liquid 10).

  The Iriodin 221 is a pearlescent pigment having blue interference light coated with rutile titanium oxide (refractive index: 2.71) on a thin plate-like substrate of mica (refractive index: 1.58). It is a thing.

  In order to dilute the (adjustment liquid 1) to (adjustment liquid 10) to a printable state, 120 parts by weight of an organic solvent was added and kneaded for 1 hour to mix and disperse the ink (coating using a pearlescent pigment) Liquids 1) to (Coating liquid 10) were prepared.

  The organic solvent used was a mixture of 65 parts by weight of cyclohexanone and 55 parts by weight of xylene.

Using the prepared (Coating liquid 1) to (Coating liquid 10), each coating liquid is dropped on a 270 mesh emulsion 10 μm thick silk screen plate, and a PET film is formed to have a film thickness of about 4 μm with a squeegee or the like. Printing was performed to prepare samples of (Example 1) to (Example 10).

  Next, the reflection luminance was evaluated visually for the samples of (Example 1) to (Example 10) produced above. The results are shown in (Table 1).

The reflection luminance was evaluated according to the following criteria.
3 ... Bright
2 ... Intermediate
1 ... dark

  As shown in (Table 1), the ink using the pearlescent pigment of (Example 1) to (Example 10) of the present invention has a refractive index of the binder based on the refractive index of the binder and the refractive index of the pearlescent pigment. By reducing, the difference in refractive index increased, the amount of reflected light at the boundary between the binder and the pearlescent pigment increased, and the brightness of the blue reflected light increased to obtain a strong pearly luster. .

DESCRIPTION OF SYMBOLS 1 Pearlescent pigment 2 Ink containing a pearlescent pigment 10 Thin plate-shaped base material 20 Metal compound 30 Binder A Observation surface side

Claims (4)

In a coating solution consisting of a pearlescent pigment and a binder, at least a thin plate-like substrate coated with a metal compound,
An ink using a pearlescent pigment, wherein the refractive index of the binder is smaller than the refractive index of the pearlescent pigment, and the difference between the refractive index of the pearlescent pigment and the refractive index of the binder is 1.0 or more.   The pearlescent pigment according to claim 1, wherein the pearlescent pigment lamellar substrate uses any one of mica, synthetic mica, alumina, silica, aluminum, borosilicate glass, talc, and kaolin. Ink.   The metal compound coated on the pearlescent pigment lamellar substrate is titanium dioxide, or ferric oxide, zirconium dioxide, antimony trisulfide, lead oxide, zinc selenide, cadmium sulfide, bismuth acid chloride, lead chloride. , Ceria, Tantalum pentoxide, Zinc sulfide, Zinc oxide, Cadmium oxide, Neodymium oxide, Antimony trioxide, Indium oxide, Silica, Alumina, Tin oxide, single layer or multilayer coating with two or more types An ink using the pearl luster pigment according to claim 1 or 2.   The refractive index of the pearl luster pigment is 1.9 or more, and the ink using the pearl luster pigment according to claim 1-3.

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