JP2002241636A - Powdery pigment composition for aqueous dispersion and method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a powdery pigment composition exhibiting an excellent dispersing property in producing an aqueous dispersion of an aqueous ink, coating material, etc. SOLUTION: This powdery material containing 45-75 wt.% range pigment is obtained by removing water content from a pigment paste containing water and the pigment by using a kneader or a vibration dryer. The pigment is selected from a phthalocyanine-based, a dioxazine violet-based, an indanthrene blue-based, a perylene-basede, a quinacridone-based, a diketopyrrolopyrrole-based and azo-based pigments. To the pigment paste, a high polymeric dispersing agent, surfactant, pigment derivative, etc., are blended as necessary.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a powdery pigment composition for an aqueous dispersion and a method for producing the same.
The present invention relates to a powder pigment composition for an aqueous dispersion which can be suitably used for an aqueous gravure ink, an aqueous automotive paint, an aqueous building material paint, and the like, and a method for producing the same.

[0002]

2. Description of the Related Art Conventionally, pigments used in inks, paints and the like have been commercialized through a drying step and a pulverizing step by adding a surfactant, a pigment derivative and the like as required.
However, after the drying step, the pigment particles agglomerate, and in particular, the finer the primary particles, the more intense the agglomeration. Particularly in the preparation of water-based paints and water-based inks, it is necessary to go through a step of dispersing the pigment in an aqueous dispersion varnish. Even if such a pigment is used, the pigment in which a strong aggregate is formed has a very poor dispersibility and cannot be easily disintegrated to a state close to primary particles. As a result, the coloring property and gloss of the obtained coating film are extremely low. Therefore, when these agglomerated pigments are used, a large amount of energy and time is wasted in dispersing in order to obtain a coating quality similar to that of a predetermined oil-based paint, for example.

In order to solve the above-mentioned inconvenience, it is conceivable to use a press cake paste pigment obtained by a filter press containing a large amount of water obtained directly from the pigment production process. However, paste-like pigments
Due to poor handling properties during transportation and preparation, there is a problem that the working efficiency is significantly reduced and the loss of pigment is likely to increase. In addition, the pigment content of a press cake of a phthalocyanine-based, dioxazine-violet-based, selen-based, perylene-based, or quinacridone-based pigment is usually 45% by weight even by dehydration using a commonly used pressure-type filter press. Degree is the limit. Therefore, in the case of a varnish having a low resin content, it may be difficult to prepare an ink, a paint, or the like, and it is also impossible to prepare a dispersion paste having a high pigment content.

[0004] To solve this problem, Japanese Patent Publication No.
Japanese Patent Publication No. 1674 discloses a pigment composition having a water content of 2 to 19% by weight, obtained by drying a non-agglomerated pigment wet cake using a hot-air dryer or the like. However, the pigment composition described in this publication merely reduces the degree of drying of the pigment, and the problem of aggregation is not completely solved. Therefore, it is difficult to obtain a water-based varnish having high dispersibility even by using this.

In Japanese Patent Publication No. 1-54374,
A pigment for printing ink having a water content of 20 to 50% by weight and a size of 1 to 50 mmφ is described. However, this molded pigment is simply dried with hot air as it is, and the dispersibility is not sufficient.

Further, when a paste such as a press cake immediately after the production of a pigment is used, the pigment in the form of fine crystals formed at the time of pigmentation agglomerates even in an aqueous system, so that a surface treatment is sometimes performed. If the preliminary dispersion of the pigment is not sufficiently solved using a machine such as a homomixer, the surface treatment is not effectively performed, and a large initial running cost is required. In addition, since the pigment and the surface treatment agent are dispersed and treated in an aqueous system and then filtered, all of the added surface treatment agent is not adsorbed on the pigment surface and moves to the filtrate side, causing loss of the surface treatment agent. In addition, there is a problem that a load is imposed on wastewater treatment.

[0007]

SUMMARY OF THE INVENTION The present invention has been made to solve such problems, and an object of the present invention is to provide a water-based gravure ink, a water-based automotive paint, a water-based building material paint and the like. Demonstrates excellent dispersibility when producing a dispersion, and even when using a varnish with a low resin content, ink,
It is an object of the present invention to provide a method for producing a pigment composition in which the preparation of a paint is easy and the added surface treatment agent is not wasted. Another object of the present invention is to provide such a pigment composition. A further object of the present invention is to provide a pigment composition which can be handled in the same manner as powder even though it is a water-containing pigment, and which has good workability such as weighing and charging.

[0008]

The process for producing a powdery pigment composition for an aqueous dispersion according to the present invention comprises removing water from a pigment paste containing water and a pigment while applying shearing force or vibration. And a powder containing a pigment in the range of 45 to 75% by weight. That is, in the present invention, the heating and drying of the pigment paste containing water and the pigment is kneaded,
By using a vibration drier or the like, drying is performed in a state where shearing force or vibration is applied to the pigment particles, and only drying until the pigment content is in the range of 45 to 75% by weight is performed. As a result, the pigment particles do not agglomerate and thus have excellent dispersibility, and a powdery pigment composition for an aqueous dispersion can be obtained.

The powder pigment composition for an aqueous dispersion according to the present invention comprises:
It is useful as a water-based ink composition, particularly useful as a water-based gravure ink composition. The powder pigment composition for an aqueous dispersion of the present invention is also useful as an aqueous coating composition, and particularly useful as an aqueous coating composition for automobiles and building materials.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The powder pigment composition for an aqueous dispersion according to the present invention contains the pigment in the range of 45 to 75% by weight as described above. When the content of the pigment is lower than 45% by weight, it is not preferable because the powder cannot be maintained. On the other hand, when the content of the pigment exceeds 75% by weight, the dispersibility of the pigment becomes low, which is not preferable.

The powdery pigment composition for an aqueous dispersion of the present invention and the method for producing the same are not particularly limited to the kind of pigment, but may be phthalocyanine, dioxazine violet, indanthrene blue, perylene. And quinacridone-based, diketopyrrolopyrrole-based (DPP) and azo-based pigments. Further, the production method of the present invention includes (a) an acid paste method and an acid slurry method for adjusting the particle size by dissolving and reprecipitating in sulfuric acid, and (b) grinding a crude product together with an inorganic salt to obtain a particle size. (C) Pigmented product by acid milling method in which acid salt is formed in a kneader, neutralized and ground to adjust particle size, (d) Vibration mill, ball mill And a pigmentized product obtained by dry pulverization with a medium using an attritor or the like.

In the present invention, a pigment paste for an aqueous dispersion is obtained by treating a pigment paste containing the above-described pigment as follows. That is, (1) the pigment paste is charged into a device capable of giving a shearing force or vibration such as a kneader or a vibration dryer, and a polymer dispersant described later therein,
A surfactant or the like is added as necessary, and the mixture is heated at normal pressure or reduced pressure to remove water.

In the powder pigment composition for an aqueous dispersion of the present invention and the method for producing the same, a polymer dispersant may be added. The addition of the polymer dispersant can be used as an alternative to the so-called surface treatment step generally performed in the pigment production step, and the quality improving effect is remarkable. The polymer dispersant that can be used is a copolymer mainly having an affinity for an acrylic pigment, for example, acrylic acid, a water-soluble resin containing maleic acid or the like as a structural unit, and specific examples thereof. Examples include polyacrylates and salts of copolymers of vinyl compounds and carboxylic acid monomers. In addition, carboxymethyl cellulose, polyvinyl alcohol, polyethylene sulfonate, liquid polyethylene glycol, polypropylene glycol and the like are also preferably used. Further, a coating varnish used when preparing an aqueous dispersion from the obtained powder pigment composition for an aqueous dispersion can also be used as a polymer dispersant. As such a coating varnish, for example, Watersol S-751 (manufactured by Dainippon Ink and Chemicals) can be mentioned.

The content of the polymer dispersant is in the range of 1 to 50% by weight (solid content), and preferably in the range of 1 to 20% by weight, based on the pure pigment contained in the pigment paste. . If the content is less than 1% by weight, the effect of dispersing the pigment is not substantially obtained, and the content is 50%.
If the amount is more than 10% by weight, excessive addition becomes excessive, so that the dispersing effect corresponding to the added amount cannot be obtained, and the adhesion and water resistance of the coating film or the ink film are undesirably reduced.

In the powder pigment composition for an aqueous dispersion of the present invention and the method for producing the same, a surfactant may be added. The addition of a surfactant can be used as an alternative step to a so-called surface treatment step generally performed in a pigment production step, and the quality improving effect is remarkable. Surfactants that can be used are not particularly limited, but those having an HLB of 8 or more are preferred. Specifically, carboxylic acid type polymer activator, alkyl benzene sulfonate, alkyl naphthalene sulfonate, polyoxyethylene alkyl sulfate,
Examples thereof include alkyl phosphates, alkyl sulfates, and dialkyl sulfone succinic acids.

The content of the surfactant is preferably in the range of 0.5 to 10% by weight based on the pure pigment contained in the pigment paste. When the content is less than 0.5% by weight, the effect of dispersing the pigment is not substantially obtained, and when the content is more than 10% by weight, excessive addition is performed, and the dispersing effect corresponding to the added amount is not obtained. It is not preferable because the adhesiveness and water resistance of the coating film and the ink film are reduced, and the adhesion and the water resistance of the coating film and the ink film are reduced.

Further, in the powder pigment composition for an aqueous dispersion of the present invention and the method for producing the same, a pigment derivative may be added. Here, the pigment derivative is a pigment in which a hydrophilic functional group is introduced into the same or different pigment as the pigment contained in the pigment paste, and the pigment dispersion for the aqueous dispersion has a dispersibility, fluidity, It is added to provide storage stability and the like. Examples of the hydrophilic functional group include an amino group, a carboxyl group, a sulfonic acid group, and a hydroxyl carbonyl group. Of these, the carboxyl group and the sulfonic acid group have excellent dispersibility, fluidity, and storage stability. And the like can be provided.

The content of the pigment derivative is preferably in the range of 1 to 18% by weight based on the pure pigment contained in the pigment paste. If this content is lower than 1% by weight,
The effect of imparting dispersibility, fluidity, storage stability and the like is not substantially obtained, and when the content is more than 18% by weight, not only the effect corresponding to the added amount is not obtained, but also the effect is obtained. It is not preferable because the adhesion, water resistance, bleeding property and the like of the coating film and the ink film are reduced.

In the present invention, the removal of water while applying a shearing force or vibration is carried out under normal pressure or reduced pressure.
It is preferable to carry out in a temperature range of 0 ° C. If this temperature range is lower than 60 ° C., it takes too much time to remove water, so that shearing force may be applied too much, causing aggregation of the pigment. If it is higher than 110 ° C., the coloring power may be reduced due to the aggregation of the pigment. It is not preferable because it invites.

[0020]

The present invention will be described below with reference to examples and comparative examples. In this specification, parts and% represent parts by weight and% by weight, respectively, unless otherwise specified.

Example 1 After crude chlorinated copper phthalocyanine was pigmented by a salt milling method using a kneader, the ground material was dispersed in warm water. Next, it was sent to a filter press, washed with water and filtered to obtain a pigmented paste-like chlorinated copper phthalocyanine pigment. 400 parts of the chlorinated copper phthalocyanine pigment paste (pure pigment equivalent) thus pigmented were charged into a 1 L kneader, and 12 parts of Diperbyk-191 (manufactured by BYK) was added as a polymer dispersant. The water was evaporated and removed until the pigment content reached about 65% while milling at an internal temperature of 60 ° in a kneader, thereby obtaining a fluid powder pigment composition having a water-containing nonvolatile content of 66.3%.

Example 2 After a crude chlorinated copper phthalocyanine was pigmented by a salt milling method using a kneader, the ground material was dispersed in warm water. Next, it was sent to a filter press, washed with water and filtered to obtain a pigmented paste-like chlorinated copper phthalocyanine pigment. 424 parts (in terms of pure pigment) of the chlorinated copper phthalocyanine pigment paste thus pigmented were charged into a 1 L kneader, and PEG # 400 (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) was used as a polymer dispersant.
Was added. Water was evaporated and removed until the pigment content reached about 65% while milling at an internal temperature of 60 ° in a kneader to obtain a fluid powder pigment composition having a water-containing nonvolatile content of 72.7%.

Example 3 After crude chlorinated copper phthalocyanine was pigmented by a salt milling method using a kneader, the ground material was dispersed in warm water. Next, it was sent to a filter press, washed with water and filtered to obtain a pigmented paste-like chlorinated copper phthalocyanine pigment. 418 parts of the chlorinated copper phthalocyanine pigment paste (pure pigment equivalent) thus pigmented were charged into a 1 L kneader, and 12.5 parts of Poise 520 (manufactured by Kao) as a surfactant was added. Pigment 6 while milling at an internal temperature of 60 ° in the kneader
By evaporating and removing the water until the water content becomes about 5%, a powdery pigment composition having a water content and having a non-volatile content of 64.7% was obtained.

Example 4 After crude chlorinated copper phthalocyanine was pigmented by a salt milling method using a kneader, the ground material was dispersed in warm water. Next, it was sent to a filter press, washed with water and filtered to obtain a pigmented paste-like chlorinated copper phthalocyanine pigment. 400 parts of the chlorinated copper phthalocyanine pigment paste (in terms of pure pigment) and 30 parts of copper phthalocyanine monosulfonic acid paste (in terms of solid content) as a pigment derivative were charged into a 1 L kneader, Dis as dispersant
12 parts of perbyk-191 (manufactured by BYK) were added.
65% pigment content while milling at 60 ° internal temperature
By evaporating and removing the water until the water was removed, a powdery pigment composition having a water content and having a nonvolatile content of 64.3% and having fluidity was obtained.

Example 5 After crude chlorinated copper phthalocyanine was pigmented by a salt milling method using a kneader, the ground material was dispersed in warm water. Next, it was sent to a filter press, washed with water and filtered to obtain a pigmented paste-like chlorinated copper phthalocyanine pigment. 400 parts (in terms of pure pigment) of the chlorinated copper phthalocyanine pigment paste thus pigmented was charged into a 1 L kneader, and water sol S-751 (acrylic resin-based varnish, manufactured by Dainippon Ink and Chemicals, Inc.) was used as a polymer dispersant. ) 20 parts by solids were added. The water was evaporated and removed until the pigment content reached about 70% while milling at an internal temperature of 60 ° in a kneader to obtain a fluid powder pigment composition having a water-containing nonvolatile content of 72.1%.

Comparative Example 1 After crude chlorinated copper phthalocyanine was pigmented by a salt milling method using a kneader, the ground material was dispersed in warm water. Next, the mixture is sent to a filter press, washed with water and filtered to obtain a desalted chlorinated copper phthalocyanine pigment paste (solid content 35%).
%).

Comparative Example 2 The chlorinated copper phthalocyanine pigment paste obtained in Comparative Example 1 was dried at 105 ° C. in an air bath, and then pulverized using an atomizer to obtain a powder pigment composition (solid content: 99.9). %).

<Gloss Test of Coating Film> The powder pigment compositions of Examples 1 to 5 and Comparative Example 2 and the pigment paste of Comparative Example 1 were used. Dispersion was performed for 60 minutes, 90 minutes, 120 minutes, and 150 minutes to obtain a dispersion paste. Water sol S-695 (water-soluble melamine having a solid content of 66%, manufactured by Dainippon Ink and Chemicals, Inc.) was added to this dispersion paste at a ratio of dispersion paste / water sol S-695 = 100/6 to obtain an aqueous baking paint. Was prepared. 4
After being colored with a mill applicator and dried, the gloss was measured at 60 ° using a digital goniospectrophotometer (UGV5D, manufactured by Suga Test Instruments Co., Ltd.). The results are shown in Table 2. The storage stability was evaluated by measuring the viscosity of each of the aqueous baking coatings initially and after storage at 40 ° C. for 10 days.

[0029]

[Table 1]

[0030]

[Table 2] As shown in Table 2, the powder pigment compositions for aqueous dispersions of Examples 1 to 4 in which water was removed while applying a shearing force using a kneader had a 60 ° gloss at any dispersion time. It is understood that the value is high and the dispersibility is very good. Also, the coloring property was excellent. Example 4 to which the pigment derivative was added had less sedimentation than the other examples and comparative examples, and was further excellent in storage stability. The powder pigment compositions of any of the examples had good handling properties at the time of weighing, charging, etc., similarly to ordinary powders.

Further, it can be seen that the aqueous baking coatings using the powdery pigment compositions of Examples 1 to 5 have a small increase in viscosity as compared with the coatings of Comparative Examples, and are excellent in storage stability.

Example 6 400 parts of a dioxazine violet paste (in terms of pure pigment) prepared as a pigment by a vibration mill method was charged into a 1 L kneader, and PEG # 400 (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) was used as a polymer dispersant. Was added in 29 parts. Pigment 6 while milling at an internal temperature of 60 ° in the kneader
By evaporating and removing the water until the water content becomes about 5%, a powdery pigment composition having a water content and having a nonvolatile content of 72.7% was obtained.

Example 7 400 parts (in terms of pure pigment) of dioxazine violet paste pigmented by a vibration mill method was charged into a 1 L kneader, and 29 parts of poise (made by Kao) was added as a surfactant. . Water was evaporated and removed until the pigment content reached about 65% while milling at an internal temperature of 60 ° in a kneader to obtain a water-containing powdery pigment composition having a nonvolatile content of 72.7% and containing water.

<Comparative Example 3> A paste of dioxane violet pigment pigmented by a vibration mill method was dried in an air bath at 105 ° C, and then pulverized by an atomizer to obtain a powder pigment composition.

<Ink Performance Test> The components shown in Formulation Composition I in Table 3 were blended, subjected to a dispersion treatment for 30 minutes, 60 minutes and 90 minutes using a paint conditioner. By adding the components shown, and again performing a dispersion treatment for 5 minutes using a paint conditioner,
An aqueous primary color ink was prepared.

Next, the components shown in the composition I of Table 4 were blended, and a dispersion treatment was performed for 30 minutes using a paint conditioner. Next, the components shown in the composition II were added, and A white ink was prepared by performing a dispersion treatment for 5 minutes using a paint conditioner.

[0037]

[Table 3]

[0038]

[Table 4] Next, a water-based light-colored ink was prepared by blending at a ratio of primary color ink / white ink = 2 g / 20 g, and was applied to white liner paper with a bar coater to examine the dispersion time dependency of coloring power. The sex was evaluated. Further, the hue and saturation of the primary color ink and the light color ink were compared on a kraft paper, a white liner paper and a high quality paper with a bar coater and a spatula.
The coloring power was measured by measuring the color of the developed colored paper with a color difference meter and obtaining the obtained V.
From the value, tinting strength (%) = (1- (V A -V B)) was determined by × 100. Here, _VA is a standard value, and here is a value where the coloring power of the dispersion time of 30 minutes in Example 6 is 100%. V _B is a measured value of each colored paper. The hue, saturation, and gloss were evaluated by visually determining the developed paper. Table 5 shows the results.

[0039]

[Table 5] From the results in Table 5, the powder pigment compositions of Examples 6 and 7 are:
Compared to the composition of Comparative Example 3, the coloring power was increased in a short time dispersion, and it was found that the composition was excellent in dispersibility in an aqueous system.
In addition, since the pigment composition obtained by the production method of the present invention is in the form of powder, quality control is easy, and the paint, the preparation in the pigment dispersion step in the production of ink, the workability such as measurement, It is very good when compared with the case where a press cake is used. Further, if the pigment content is set to about 70%, the cost for transporting the product can be reduced as compared with the case where the pigment press cake is transported.

When used in water-based paints, water-based inks, etc., they have good dispersibility, show good color development in a short time, and have a clear color tone as compared with those dispersed from powdered pigments or pigment press cakes. High gloss and coloring power. Also, the fluidity is good.

[0041]

The pigment composition for aqueous dispersion obtained by the production method of the present invention has the same form as the powder pigment, so that the handleability is good and the workability such as weighing and charging is improved. . Further, since the pigment content is higher than that of a normal pigment press cake, the content of the pigment can be increased even in the preparation of a paint.

In terms of quality, the use of the composition of the present invention makes it possible to obtain an aqueous dispersion having good dispersibility, excellent color development and gloss, and a final product having a clear color tone. be able to. Furthermore, the composition of the present invention using the pigment derivative has excellent storage stability.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (reference) C09D 11/02 C09D 11/02 17/00 17/00 201/00 201/00 F term (reference) 4J037 AA30 CB21 CC02 CC12 CC15 CC16 CC25 EE25 EE28 EE35 EE43 FF15 FF23 4J038 EA011 KA08 MA08 MA10 NA01 NA23 NA27 4J039 BE01 CA06 DA05 EA27 EA33

Claims (18)

[Claims] 1. A powder containing a pigment in the range of 45 to 75% by weight by removing water from a pigment paste containing water and a pigment while applying a shearing force or vibration. Of producing a powdery pigment composition for an aqueous dispersion. 2. The method for producing a powder pigment composition for an aqueous dispersion according to claim 1, wherein the shearing force or the vibration is applied using a kneader or a vibration dryer. 3. The pigment is selected from the group consisting of phthalocyanine, dioxazine violet, indanthrene blue, perylene, quinacridone, diketopyrrolopyrrole, and azo. The method for producing a powdery pigment composition for an aqueous dispersion according to claim 1. 4. The method for producing a powder pigment composition for an aqueous dispersion according to claim 1, wherein the pigment paste further contains a polymer dispersant. 5. The aqueous dispersion according to claim 4, wherein the content of the polymer dispersant is in a range of 1 to 50% by weight based on a pure pigment contained in the pigment paste. A method for producing a body pigment composition. 6. The method for producing a powder pigment composition for an aqueous dispersion according to claim 1, wherein the pigment paste further contains a surfactant. 7. The method for producing a powder pigment composition for an aqueous dispersion according to claim 6, wherein the surfactant has an HLB of 8 or more. 8. The aqueous dispersion according to claim 6, wherein a content of the surfactant is in a range of 0.5 to 10% by weight based on a pure pigment contained in the pigment paste. A method for producing a powder pigment composition. 9. The method for producing a powdery pigment composition for an aqueous dispersion according to claim 1, wherein the pigment paste further contains a pigment derivative. 10. The powder pigment for an aqueous dispersion according to claim 9, wherein the pigment derivative is a compound obtained by introducing a hydrophilic group into the same or different pigment as the pigment contained in the pigment paste. A method for producing the composition. 11. The method for producing a powder pigment composition for an aqueous dispersion according to claim 10, wherein the hydrophilic group is a carboxyl group or a sulfonic acid group. 12. The method according to claim 9, wherein the content of the pigment derivative is in a range of 1 to 18% by weight with respect to a pure pigment contained in the pigment paste. The manufacturing method as described. 13. The powder pigment composition for an aqueous dispersion according to claim 1, wherein the removal of the water is performed at a temperature range of 60 to 110 ° C. under normal pressure or reduced pressure. Method of manufacturing a product. 14. A powder pigment composition for an aqueous dispersion obtained by the method for producing a powder pigment composition for an aqueous dispersion according to any one of claims 1 to 13. 15. An aqueous ink composition containing the powder pigment composition for an aqueous dispersion according to claim 14. 16. A composition for an aqueous gravure ink, comprising the powder pigment composition for an aqueous dispersion according to claim 14. 17. An aqueous automotive coating composition comprising the powder pigment composition for an aqueous dispersion according to claim 14. 18. A coating composition for an aqueous building material, comprising the powder pigment composition for an aqueous dispersion according to claim 14.