JP2003165925A - Pigment composition and production method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a pigment composition excellent in tinting power and color stability. <P>SOLUTION: The pigment composition is obtained by dry grinding a mixture containing a color pigment and an extender pigment at a weight ratio of (5:95) to (90:10). It is desirable that the extender pigment comprises a precipitated barium sulfate, the color pigment in the obtained pigment composition has a mean particle diameter of 300 nm or smaller, and the weight ratio of the color pigment to the extender pigment is (10:90) to (50:50). <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a pigment composition. More specifically, it relates to a pigment composition having excellent tinting strength and color stability.

[0002]

Various studies have been made in order to obtain a pigment composition having excellent tinting strength and color stability. For example, in JP-A-1-193366, an organic pigment, an inorganic ammonium salt, and a grinding aid such as a water-soluble aromatic compound or an amino acid are mixed, and the grinding aid is removed. A method for producing the pigment composition is described. However, in this method, since it is necessary to remove the grinding aid after mixing, the manufacturing process of the pigment composition is complicated. Further, since the grinding aid is removed with water and dried, reaggregation of the pigment particles occurs, and it is difficult to obtain a pigment composition having uniform particles, and there is a problem that the coloring power decreases. further,
White pigment (eg, titanium oxide) or black pigment (eg, carbon black) is added to the obtained pigment composition.
When mixing and toning, preparing and applying colored paint,
There is a problem that the stability of color over time is poor.

Further, JP-A-58-187459 describes a pigment composition obtained by dry-mixing an inorganic pigment and a plastic powder. This pigment composition is
It is a pigment mainly intended to improve the sedimentation property of the pigment, and is a composite pigment in which an inorganic pigment adheres to the surface of plastic powder. However, there are problems that the tinting strength and color stability are poor, and that the pigments are limited to inorganic pigments.

The invention described in Japanese Patent Application Laid-Open No. 9-25431 aims at improving problems such as precipitation and fluidity of the pigment in the dispersion by coexisting the pigment and the fine particles in the water-based paint. However, there is no description about improving color stability, not improving coloring power.

Further, Japanese Patent Application Laid-Open No. 4-292664 discloses a composite pigment in which a specific pigment is attached to the surface of an inorganic or organic powder. However, when this composite pigment is used as a paint, the problem of poor coloring power and color stability is not improved.

[0006]

Therefore, there is a demand for a pigment composition which is excellent in coloring power and stability of color over time, and a method for producing the same.

[0007]

The present invention provides a pigment composition obtained by dry-milling a mixture containing a color pigment and an extender pigment in a weight ratio of 5:95 to 90:10.

In a preferred embodiment, the extender pigment is barium sulfate, especially precipitating barium sulfate.

Further, in a preferred embodiment, the average particle diameter of the color pigment in the pigment composition is 300 nm or less.

The present invention also provides a pigment-dispersed paste containing the pigment composition.

Further, the present invention provides a paint containing the above pigment composition.

The present invention also provides a method for producing a pigment composition, which comprises a step of mixing a color pigment and an extender pigment in a weight ratio of 5:95 to 90:10 and dry pulverizing.

In a preferred embodiment, the extender pigment is barium sulfate, especially precipitating barium sulfate.

In a further preferred embodiment, the color pigment is dry pulverized to have an average particle diameter of 300 nm or less.

The above problems can be solved by these inventions.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION The pigment composition of the present invention is obtained by dry pulverizing a mixture containing a color pigment and an extender pigment in a weight ratio of 5:95 to 90:10. The average particle diameter of the color pigment in this pigment composition is preferably 30.
It is 0 nm or less. The average particle size of the color pigment is 300 nm
When it exceeds, it tends to be difficult to realize high coloring power, but when it is 300 nm or less, dispersibility is good and high coloring power is realized. The thickness is more preferably 200 nm or less, further preferably 100 nm or less.

The advantages of the pigment composition of the present invention over the prior art are as follows. In the pigment composition described in JP-A-1-193366, it is necessary to remove the crushing aid using a solvent, water, etc. in the manufacturing process, and reaggregation is performed in the drying step after the crushing aid removal treatment. Easily occurs, the coloring power is not sufficient, and there is a problem in color stability. On the other hand, in the present invention, there is no step of removing the crushing aid, the manufacturing process is simplified, and there is no problem of re-aggregation of the pigment. Therefore, the obtained pigment composition has an excellent coloring power. And has excellent color stability when used as a paint. Furthermore, the pigment composition of the present invention is obtained by mixing an extender pigment and a coloring pigment and dry-milling them,
Not only color pigments, but extender pigments are also crushed into small pieces. Therefore, it has excellent gloss and transparency when used as a paint.

The weight ratio of the color pigment to the extender pigment is 5: 9.
It is 5 to 90:10. It is preferable to be in this range from the viewpoint of coloring power and color stability. 10: 90-5
0:50 is more preferable, and 20:80 to 50:50 is further preferable.

The color pigment is a pigment for giving a desired color, and includes organic pigments and inorganic pigments.

The organic pigment is not particularly limited, and a monoazo pigment, a disazo pigment, an anthraquinone pigment,
Examples include quinacridone pigments, perylene pigments, diketopyrrolopyrrole pigments, isoindolinone pigments, indanthrone pigments, phthalocyanine pigments, flavanthron pigments, dioxazine pigments, and benzidine pigments. Not limited to.

Examples of the inorganic pigment include metal oxides, sulfides and sulfates. Examples include, but are not limited to, titanium oxide, zinc oxide, red iron oxide, yellow iron oxide, yellow lead, navy blue, carbon black, graphite, and the like.

The extender pigment is a white pigment having almost no hiding power and is not intended for coloring. Examples thereof include, but are not limited to, calcium carbonate, barium sulfate (particularly precipitated barium sulfate), kaolin, alumina, silica, talc, mica, zinc phosphate and the like. Of these, barium sulfate, particularly precipitable barium sulfate, is preferably used.

The color pigment and the extender pigment are mixed in the above predetermined weight ratio and dry-ground. The dry pulverization method is not particularly limited. Generally, a high-speed rotary impact crusher such as a hammer mill, a pin mill and a disc mill, a roller mill, a ball mill, a jet mill, a raker, an automatic mortar, a vibration mill and the like can be mentioned, but not limited to these.

Dry pulverization is carried out by mixing a color pigment and an extender pigment as essential raw materials, but if necessary, in order to improve the fluidity of the pigment composition, a small amount (preferably with respect to the pigment composition) is used. 0.5 to 2% by weight) may be further added. Examples of the grinding aid include, but are not limited to, white carbon, sugars, dextrin, powdered cellulose, surfactants, alcohols, water, bentonite, and zeolite.

There are no particular restrictions on the time or temperature of dry pulverization.
Generally, it is desirable to carry out the crushing so that the particle diameter of the color pigment becomes a primary particle diameter or smaller, from the viewpoint of improving the coloring power and the stability of color. The dry pulverization may be visually terminated when the color change of the color pigment disappears,
When observing with a scanning electron microscope (TEM), the pulverization may be terminated when the color pigment reaches a target particle size.

Upon completion of dry pulverization, the pigment composition of the present invention is obtained. The obtained pigment composition is used as it is for the preparation of a pigment dispersion paste or paints such as water-based paints, solvent-based paints and powder paints. For example, a solvent and a pigment dispersion resin are mixed with the pigment composition of the present invention, the pigment is dispersed using an appropriate disperser (for example, SG mill, etc.), and the obtained pigment dispersion paste is further provided with a surface conditioner. , Hardener, etc., which are usually added to paint,
The paint is prepared. Further, the pigment composition of the present invention, a resin for powder coating, a curing agent, other additives and the like are mixed, melt-kneaded, and then pulverized to obtain a powder coating. Furthermore, it can be naturally used for coloring plastics, inks, etc., as well as for coating applications.

A solvent, a pigment dispersion resin, a surface conditioner, a curing agent, etc. for preparing a pigment dispersion paste or paint using the pigment composition of the present invention usually requires materials used by those skilled in the art. Used according to.

[0028]

EXAMPLES The present invention will be described below with reference to examples.
It goes without saying that the present invention is not limited to these examples.

(Examples 1 to 4) The coloring pigment shown in Table 1 and the extender pigment were blended in the weight ratio shown in Table 1, and an automatic mortar ANM-200W (manufactured by Nitto Kagaku Co., Ltd.) was used. Then, dry milling was performed at room temperature for 9 hours. As an extender pigment,
In all cases, precipitated barium sulfate ST (manufactured by Barite Industry Co., Ltd.) was used. The obtained pigment composition is collected, ultrasonically disperse the colored pigment in ethanol, dropped on a mesh with a collodion film, fixed on the collodion film, and observed with a scanning electron microscope (TEM) to observe the colored pigment particles. went. FIG. 1 shows an electron micrograph of color pigment particles (Example 1) crushed together with an extender pigment.

Comparative Examples 1 to 4 In the same manner as in Example 1 except that the extender pigment was not added to the coloring pigments shown in Table 1 (that is, only the coloring pigments were used), an automatic mortar ANM-200W (Nissou Kagaku Co., Ltd. )) Was pulverized at room temperature for 9 hours. The results of observing with a TEM in the same manner as in Example 1 by collecting the color pigment are shown in FIG.

[0031]

[Table 1]

As shown in the results of FIGS. 1 and 2, the particles of the color pigment crushed together with the extender pigment (FIG. 1) were smaller than those obtained by crushing only the color pigment. TEM
In the photograph (magnification: 50,000 times), the major axis particle size of any particle was measured with a caliper, and the average value of 20 particles was measured as the average particle size. The average of the colored pigments in the pigment composition of the present invention was measured. The particle size was about 38 nm. Further, the color pigments of Examples 2 to 4 and the color pigments of Comparative Examples 2 to 4 were treated in the same manner as in Example 1, and the same results as in Example 1 and Comparative Example 1 were obtained (not shown). No).

(Example 5) The pigment composition obtained in Example 1 (coloring pigment: Hoster Palm Yellow H3G) was blended in the proportions shown in Table 2 to prepare a pigment dispersion paste.

[0034]

[Table 2]

The acrylic resin used was Acridic A-405 (manufactured by Dainippon Ink), and the solvent A was a mixture of Solvettes 100 (manufactured by Esso Standard Co., Ltd.) and methyl isobutyl ketone in a weight ratio of 1: 1. It was done.

First, the solvent A is added to the acrylic resin and premixed, and the same weight as the premix paste is added to 1.5.
mmφ glass beads were added as a dispersion medium and dispersed with an SG mill, and when the particle size of the grind gauge was 10 μm or less, the operation was terminated to obtain a pigment dispersion paste 1.

On the other hand, titanium oxide, acrylic resin, and solvent A were dispersed in the blending ratios shown in Table 2 by the same method as in the preparation of the pigment dispersion paste 1 to prepare a white paste 1 for hue adjustment. did. TAIPAKE CR-95 (manufactured by Ishihara Sangyo Co., Ltd.) was used as titanium oxide.

100 parts by weight of the obtained white paste 1 was added, and 102.2 parts by weight of an acrylic resin and 4.4 parts by weight of a solvent A were added thereto to prepare a white paint A.

To the white paint A, the above-prepared pigment dispersion paste 1 was added so that the titanium oxide / coloring pigment (weight ratio) was 100/1, and further, a melamine resin (superbeckamine) as a curing agent. J-820 (manufactured by Dainippon Ink and Chemicals, Inc.) was added to the acrylic resin 7 in a weight ratio of 3. The obtained mixed liquid was stirred with a disper (4000 rpm) for 5 minutes to prepare a coating material.
Apply the paint to the art paper to a thickness of 20 μm,
It was baked at 150 ° C. for 10 minutes. Spectral colorimeter CM-1000
(Minolta Co., Ltd.) was used to measure the reflectance (R∞) of the coated plate at the maximum absorption wavelength, and the following Kubelka-Munk equation: K / S = (1-R∞) ² / 2R∞ Then, the K / S value of the coating film was calculated.

(Comparative Example 5) The pulverized color pigment obtained in Comparative Example 1, the extender pigment, the acrylic resin and the solvent A were mixed in the blending ratios shown in Table 2, and the same method as in Example 5 was used. To obtain a pigment dispersion paste 5. Precipitating barium sulfate ST was used as the extender pigment because the pigment of Comparative Example 1 had the same pigment composition as that of Example 1.

The pigment dispersion paste 5 thus obtained was used in Example 5.
Using the same method as above, paint, apply and bake, measure the reflectance (R∞) at the maximum absorption wavelength of the coated plate, and
The S value was calculated.

Using the K / S value of Comparative Example 5 as the coloring power of 100, the coloring power of the pigment composition of Example 1 used in Example 5 was calculated. The results are shown in Table 3.

[0043]

[Table 3]

The results show that when the pigment composition of the present invention is used, the coloring power is improved by 30%.

(Example 6) Pigment dispersion paste 2 was prepared in the same manner as in Example 5 except that the pigment compositions of Examples 2 and 3 were mixed with the polyester resin and solvent B in the composition shown in Table 4. And 3 were prepared.

The polyester resin used is Byron 23
The solvent B is CS (manufactured by Toyobo Co., Ltd.), and the solvent B is a mixture of anone and Solvesso 150 (manufactured by Esso Standard Co., Ltd.) in a weight ratio of 1: 1.

On the other hand, a white paste 2 (WP2) for hue adjustment having the formulation shown in Table 4 was prepared in the same manner as in Example 5. The titanium oxide used was Typake CR-97.
(Manufactured by Ishihara Sangyo Co., Ltd.).

100 parts by weight of the obtained white paste 2 was added, and 43.4 parts by weight of a polyester resin, 4.2 parts by weight of a melamine resin (Sumimar M40ST (Sumitomo Chemical Co., Ltd.)), and a solvent B were added. White paint B was prepared by adding 4.5 parts by weight.

The weight ratio of the titanium oxide in the white paint B to the color pigment of Example 2 and the color pigment of Example 3 (titanium oxide: color pigment of Example 2: color pigment of Example 3) was 1.
The white paint B, the pigment dispersion paste 2 and the pigment dispersion paste 3 were mixed so as to be 00: 5: 1 to prepare a paint. Half of the mixture is stirred with a disper (4000 rpm) for 5 minutes, applied to a tin plate with a bar coater (# 30), and baked at 230 ° C for 1 minute to prepare a coated plate, and a color difference meter C
The color was measured using R-300 (manufactured by Minolta Co., Ltd.) to determine the colorimetric value of the initial coated plate. The other half was stored at 60 ° C. for 3 days, and then a coated plate (coated plate after storage) was prepared in the same manner, and the colorimetric value was determined. Then, the color difference (ΔE) between the colorimetric value of the initial coated plate and the colorimetric value of the coated plate after storage was determined. The results are shown in Table 5.

Example 7 Pigment dispersion paste 4 was prepared by using the pigment composition of Example 4 in the same manner as in Example 5 with the composition shown in Table 4. Using the pigment dispersion paste 3 obtained in Example 6 and this pigment dispersion paste 4,
A coating material was prepared according to Example 6. That is, the weight ratio of the titanium oxide in the white paint B, the color pigment of Example 3 and the color pigment of Example 4 (titanium oxide: color pigment of Example 3: color pigment of Example 4) was 100: 5. The paint was prepared by mixing the white paint, the pigment-dispersed paste 3 and the pigment-dispersed paste 4 so that the ratio was 1: 1. A coated plate was formed using this paint in the same manner as in Example 6, and the color difference (ΔE) between the colorimetric value of the initial coated plate and the colorimetric value of the coated plate after storage was determined. The results are shown in Table 5.

(Comparative Example 6) Pigment dispersion pastes 6 and 7 having the composition shown in Table 4 and containing the color pigments of Comparative Example 2 and Comparative Example 3, respectively, were prepared in the same manner as in Example 5 as shown below. Was prepared. The pigment dispersion pastes 6 and 7
Does not contain extender barium sulfate ST which is an extender pigment. Similar to Example 6, the weight ratio of the titanium oxide in the white paint B, the color pigment of Comparative Example 2 and the color pigment of Comparative Example 3 (titanium oxide: color pigment of Comparative Example 2: comparative example 3).
White pigment B, pigment-dispersed paste 6 and pigment-dispersed paste 7 such that the color pigment) is 100: 5: 1.
Were mixed to prepare a paint. A coated plate was formed in the same manner as in Example 6, and the color difference (ΔE) between the colorimetric value of the initial coated plate and the colorimetric value of the stored coated plate was determined. The results are shown in Table 5.

Comparative Example 7 A pigment-dispersed paste 8 containing the color pigment of Comparative Example 4 was prepared by the same method as in Example 5 with the composition shown in Table 4. The pigment-dispersed paste 8 does not contain an extender barium sulfate ST which is an extender pigment. Using Pigment Dispersion Paste 7 and Pigment Dispersion Paste 8, the weight ratio of titanium oxide in white paint B, the color pigment of Comparative Example 3 and the color pigment of Comparative Example 4 (titanium oxide: Color pigment of Comparative Example 3: Comparative Example 4
The white paint B, the pigment dispersion paste 7 and the pigment dispersion paste 8 were mixed so that the color pigment) was 100: 1: 10. A coated plate was formed in the same manner as in Example 6, and the color difference (ΔE) between the colorimetric value of the initial coated plate and the colorimetric value of the stored coated plate was determined. The results are shown in Table 5.

[0053]

[Table 4]

[0054]

[Table 5]

In Comparative Example 6 and Comparative Example 7, the color difference between the coated plate after storage and the initial coated plate was large. On the other hand, in Examples 6 and 7, the color difference between the coated plate after storage and the initial coated plate was small, and it was shown that the pigment was stably stored even during storage.

Example 8 When the pigment dispersion paste of Example 5 was prepared, the time point at which 1.5 mmφ glass beads were added as a dispersion medium was set to 0 hour, and the pigment dispersion paste was sampled with time. The sampled pigment dispersion paste was blended with the white paste 1 prepared in advance in the blending ratio shown in Table 2, a coating material was prepared in the same manner as in Example 5, and coated on art paper so as to have a thickness of 20 μm.
It was baked for 10 minutes. Using a spectrophotometer CM-1000,
The reflectance (R∞) of the coated plate at the maximum absorption wavelength was measured, the K / S value of the pigment was calculated, and the change in coloring power over time was determined.

(Comparative Example 8) A coating material was prepared in the same manner as in Example 8 except that the pigment-dispersed paste was prepared according to the composition of Comparative Example 5, and the K / S value of the pigment was calculated.

The K / S value of Comparative Example 8 when dispersed for 8 hours was 10
As 0, the dispersibility of Example 8 and Comparative Example 8 were compared. The results are shown in Fig. 3.

The results show that the paint using the pigment composition of the present invention is more easily dispersed and the coloring power is greatly improved as compared with the conventional paint.

[0060]

In the pigment composition of the present invention, since the color pigment is pulverized by the dry pulverization method together with the extender pigment, the average particle diameter of the obtained color pigment is small and there is almost no reaggregation. Therefore, it is excellent in dispersibility, coloring power and storage stability when used as a paint.

[Brief description of drawings]

FIG. 1 is an electron micrograph of particles of a coloring pigment crushed with an extender pigment.

FIG. 2 is an electron micrograph of particles of a color pigment when only the color pigment is crushed.

FIG. 3 is a graph showing the dispersibility and tinting strength of the pigment composition of the present invention.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) C09C 1/02 C09C 1/02 C09D 7/12 C09D 7/12 17/00 17/00 201/00 201 / 00 (72) Harunori Goji 19-17 Ikedanaka-cho, Neyagawa-shi, Osaka Prefecture F-term in Japan Paint Co., Ltd. (reference) 4J037 AA01 AA02 AA09 AA10 AA11 AA15 AA21 AA24 AA26 CB28 DD05 EE08 EE28 EE29 EE44 FF03 4J038 HA026 HA026 HA166 HA286 HA376 HA526 HA536 HA546 JB16 JB25 KA03 KA08 PA02

Claims (8)

[Claims] 1. A weight ratio of a color pigment and an extender pigment is 5: 9.
A pigment composition obtained by dry pulverizing a mixture containing 5 to 90:10. 2. The pigment composition according to claim 1, wherein the extender pigment is barium sulfate. 3. The pigment composition according to claim 1, wherein the average particle diameter of the color pigment in the pigment composition is 300 nm or less. 4. A pigment-dispersed paste containing the pigment composition according to any one of claims 1 to 3. 5. A paint containing the pigment composition according to any one of claims 1 to 3. 6. The weight ratio of the color pigment to the extender pigment is 5: 9.
A method for producing a pigment composition, comprising a step of mixing in a ratio of 5 to 90:10 and dry pulverizing. 7. The method according to claim 6, wherein the extender pigment is barium sulfate. 8. The color pigment has an average particle diameter of 300 nm.
The method according to claim 6 or 7, wherein the method is dry-milled as follows.