JP2006299050A - Dispersing agent for pigment and pigment composition containing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a dispersing agent for a pigment, which prevents aggregation of pigment particles dispersed in ink or the like and facilitate manufacturing e.g. ink with excellent stability and flowability. <P>SOLUTION: The pigment composition comprises a compound of formula (I). In the formula, R<SB>1</SB>-R<SB>3</SB>are each H, a halogen or an alkyl group; M is H, a metal, an ammonium group, or an amine group; and n is a number of 0.1-3. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a pigment dispersant and a pigment composition using the same.

  Generally, when a pigment is mixed and dispersed in a vehicle such as paint, gravure ink, offset ink or the like, it is difficult to stably disperse the pigment in the vehicle. Fine pigment particles once dispersed in the vehicle are There is a tendency to aggregate in the vehicle. As a result, the viscosity of the vehicle in which the pigment is dispersed is increased, or the coloring power of the ink or paint using the vehicle in which the pigment is dispersed is decreased, or the gloss of the coating film is decreased. Will occur.

For example, a pigment dispersion for a color filter, although the pigment content is usually in the range of 5 to 10% by mass, the dispersion state does not agglomerate pigment particles and is as low as about 5 to 20 mPa · s. It must be of good viscosity and storage stability. In order to solve these problems, in Patent Document 1 and Patent Document 2, a phthalocyanine blue pigment derivative is added to a green pigment, and an ansanthrone pigment derivative is added to a red pigment as a pigment dispersant. It has been proposed that pigment aggregation can be prevented and a uniform pigment dispersion can be obtained.
JP 60-237403 A JP 60-247603 A

  On the other hand, liquid crystal display devices have been expanded from monitors for personal computers to color displays for color televisions, and demands for further performance improvements for color filters have increased, improving the transparency of colored pixels and transmitting colored pixels. There has been a need to increase the contrast of light and to increase the pigment content of colored pixels. However, in the method using the above pigment derivative, it is difficult to improve the transparency of the colored pixel by improving the dispersibility of the pigment, and to prevent an increase in viscosity and a decrease in storage stability due to an increase in the pigment concentration. These improvements are desired.

  Accordingly, the object of the present invention is to provide printing ink (offset ink, gravure ink, etc.), various paints, pigment printing agents, electrophotographic dry toner or wet toner, ink jet recording ink, thermal transfer recording ink, writing instrument ink, By providing a pigment dispersant that prevents the aggregation of pigment particles dispersed in these inks and the like, and has excellent fluidity and enables stable production of the above inks, etc., in the production of color filters and the like. is there.

（但し、式（Ｉ）中のＲ₁、Ｒ₂、Ｒ₃は同じでも異なってもよく、水素原子、ハロゲン原子またはアルキル基であり、Ｍは水素原子、金属、アンモニウム基またはアミン基であり、ｎはスルホン基の平均導入個数であり、０．１〜３の数である。） The above object is achieved by the present invention having the following constitution.
1. A pigment dispersant comprising a compound represented by the following general formula (I):

(In the formula (I), R ₁ , R ₂ and R ₃ may be the same or different and are a hydrogen atom, a halogen atom or an alkyl group, and M is a hydrogen atom, a metal, an ammonium group or an amine group. , N is the average number of introduced sulfone groups, and is a number from 0.1 to 3.)

2. A pigment composition comprising a pigment and a dispersant, wherein the dispersant is the pigment dispersant described in 1 above.
3. 3. The pigment composition according to 2 above, wherein the mixing ratio of the dispersant is 0.05 to 40 parts by mass with respect to 100 parts by mass of the pigment.
4). 3. The pigment composition as described in 2 above, wherein the pigment is an organic pigment.
5. The pigments are CIPigment Red 146, CIPigment Red 177, CIPigment Red 208, CIPigment Red 242, CIPigment Red 254, CIPigment Red 255, CIPigment Yellow 138, CIPigment Yellow 139, CIPigment Yellow 150, CIPigment Yellow 185, CIPigment Green 7 and CIPigment Green 36 3. The pigment composition as described in 2 above, which is a pigment selected from

6). 3. The pigment composition as described in 2 above, which is a colorant for gravure printing ink.
7). 3. The pigment composition as described in 2 above, which is a paint colorant.
8). 3. The pigment composition as described in 2 above, which is a color filter colorant.
9. 9. The color filter colorant as described in 8 above, wherein the photosensitive resin varnish contains the pigment composition as described in 2 above.

  According to the present invention described above, the pigment dispersant of the present invention includes printing ink, various paints, plastics, pigment printing agents, electrophotographic dry toner or wet toner, ink jet recording ink, thermal transfer recording ink, and color filter. For all pigments including resists and inks for writing instruments, all pigments, including organic pigments and inorganic pigments, remarkably improve the fluidity of inks and paints, and prevent aggregation of pigment particles. A colored article exhibiting excellent gloss and sharpness can be provided.

  Next, the present invention will be described in more detail with reference to the best mode for carrying out the invention. The pigment dispersant of the present invention is characterized by having a yellow to magenta anthraquinonylaminotriazine structure in its structure, and the pigment dispersant of the present invention has excellent affinity for various pigments. And can be used to disperse a wide range of pigments. Moreover, since the pigment dispersant of this invention has the outstanding pigment dispersion effect, it can be used for manufacture of the coloring agent used in various uses.

  An example of the synthesis of the compound of the general formula (I), which is a dispersant used mainly in the present invention and characterizes the present invention, is, for example, CIPigment Yellow 147 is concentrated sulfuric acid, fuming sulfuric acid according to a conventionally known method. Sulfonated by reacting with chlorosulfonic acid, sulfur trioxide, etc., to obtain the compound represented by the general formula (I) (M = H). Moreover, the metal salt, its ammonium salt, or an amine salt can be obtained by a conventionally well-known method using the compound (M = H) represented by the said general formula (I).

  The mixing ratio of the pigment dispersant of the present invention to the pigment is preferably 0.05 to 40 parts by mass, more preferably 0.1 to 10 parts by mass with respect to 100 parts by mass of the pigment. If the blending ratio of the dispersant is too small, it is difficult to sufficiently obtain the effect of the intended dispersant. In addition, if the blending ratio of the dispersant is too large, the effect of many uses cannot be obtained, and conversely, the physical properties of the paint or ink vehicle using the resulting pigment composition are lowered, and further, The hue of the pigment to be dispersed greatly changes depending on the color of the dispersant itself.

  Examples of pigments that can be dispersed by using the pigment dispersant of the present invention include azo pigments, phthalocyanine pigments, quinacridone pigments, anthraquinone pigments, dianthraquinonyl pigments, isoindoline pigments, perylene / perinone. Pigments, dioxazine pigments, indanthrone pigments, flavanthrone pigments, ansanthrone pigments, pyranthrone pigments, diketopyrrolopyrrole pigments, vat dyes, basic dyes and other organic pigments, And inorganic pigments such as titanium oxide, carbon black, bitumen, ultramarine blue, dial, iron black, zinc white, yellow lead, and complex oxide pigments.

  Among these, CIPigment Red 146, CIPigment Red 177, CIPigment Red 208, CIPigment Red 242, CIPigment Red 254, CIPigment Red 255, CIPigment Yellow 138, CIPigment Yellow 139, CIPigment Yellow 150, A pigment selected from CIPigment Yellow 185, CIPigment Green 7 and CIPigment Green 36 is preferred.

The method for using the pigment dispersant of the present invention is not particularly limited, and examples thereof include the following methods.
1. The pigment and the dispersant are mixed in advance by a known method, and the obtained pigment composition is added to a vehicle or the like to disperse the pigment in the vehicle.
2. When the pigment is dispersed in the vehicle or the like, the pigment and the dispersant are separately added to the vehicle or the like at a predetermined ratio and dispersed in the vehicle.
3. After the pigment and the dispersant are separately dispersed in a vehicle or the like, the obtained dispersions are mixed at a predetermined ratio.
4). A dispersant is added at a predetermined ratio to a dispersion obtained by dispersing the pigment in a vehicle or the like to disperse the pigment.
Any of these methods can achieve the desired pigment dispersion effect. However, the method 1 or 2 is more effective.

  The pigment composition containing the pigment dispersant of the present invention can be produced by mixing the pigment and the dispersant by various conventionally known methods, and the production method is not particularly limited. For example, pigment powder and dispersant powder are mixed without using a disperser; pigment and dispersant are mechanically mixed with various dispersers such as a kneader, roll, and attritor; water-based or organic A method in which a liquid in which the pigment dispersant of the present invention is dissolved or finely dispersed is added to and mixed with a solvent-based pigment suspension, and the dispersant is uniformly deposited on the surface of the pigment; a solvent having strong dissolving power such as sulfuric acid There is a method in which a pigment and a dispersant are dissolved, and then both are co-precipitated with a poor solvent such as water. Thus, when preparing a pigment composition, you may use with forms, such as a solution, a slurry, a paste, and a powder, and the effect of this invention can be expressed also in any form.

  In addition, the pigment dispersant of the present invention can be used alone or in combination of two or more, and a conventionally known dispersant such as rosin, polymer dispersant, surfactant or polar group is introduced. It can also be used in combination with pigment derivatives and the like. The use of the pigment composition of the present invention is not particularly limited, and examples thereof include various printing inks, paints, plastics, pigment printing agents, electrophotographic dry toners or wet toners, ink jet recording inks, thermal transfer recording inks, and writing tools. It can be used as a colorant for various applications such as inks and color filters. In particular, the pigment composition of the present invention is useful as a colorant for color filters that require high dispersibility of the pigment.

  In general, the colorant for the color filter includes a pigment, for example, a photosensitive resin varnish such as a photosensitive polyacrylate resin, a photosensitive polyamide resin, a photosensitive polyimide resin, an unsaturated polyester resin, or the like. It is produced by highly dispersing in a varnish to which a monomer as a reaction diluent is added. At that time, by using the pigment dispersant of the present invention or the pigment composition of the present invention, a color filter color filter with high dispersion stability and high transmittance can be obtained.

  For example, Japanese Patent Laid-Open No. 10-338832 describes that a pigment derivative and a cationic polymer dispersant are blended into a pigment and used as a colorant for a color filter. By using the pigment dispersant of the present invention, a color filter colorant having high pigment dispersion stability and high transmittance can be produced.

Next, the present invention will be described more specifically with reference to synthesis examples, examples and comparative examples. In the text, “part” or “%” is based on mass.
[Synthesis Example 1]
45 parts of CIPigment Yellow 147 was added to 335 parts of 20% fuming sulfuric acid at 30 ° C. or lower, and reacted at 60 to 65 ° C. for 6 hours for sulfonation. Thereafter, this reaction mixture was precipitated in 4000 parts of ice water, and filtration and washing with water were repeated. After drying, 43 parts of the following dispersant (A) having an average of 0.9 sulfone groups introduced per molecule was obtained from the result of elemental analysis of sulfur.

[Synthesis Example 2]
Add 49 parts of water paste (15.0 parts of solid content) of Synthesis Example 1 to 500 parts of water and reslurry well. Add 9.5 parts of tetraethylammonium chloride and stir for 10 minutes. The mixture was gradually neutralized to weak acidity, filtered after stirring for 3 hours, and sufficiently washed with water to obtain 18 parts of the following dispersant (B).

[Synthesis Example 3]
In Synthesis Example 1, instead of CIPigment Yellow 147, anthraquinonylaminotriazine in which a methyl group was substituted at the ortho position of the phenyl group was used, and the following dispersant (C) was obtained in the same manner.

[Synthesis Example 4]
Further, the dispersant (C) and tetraethylammonium chloride were reacted in the same manner as in Synthesis Example 1 to obtain the following dispersant (D).

[Examples 1 to 4]
In order to evaluate the effect of the pigment dispersant of the present invention, a gravure ink having the following formulation (1) was prepared.
Formulation (1)
-Pigment 9.5 parts-Dispersants (A) to (D) 0.5 parts-Nitrified cotton varnish 16.0 parts-Polyamide varnish 20.0 parts-Thinner 54.0 parts Naphthol AS monoazo pigment (CIPigment Red 146), and dispersants (A) (Example 1), (B) (Example 2), (C) (Example 3), and (D) obtained in Synthesis Examples 1 to 4, respectively. Using Example 4), the above ingredients were placed in a container, glass beads were added and dispersed with a paint conditioner to prepare four types of gravure polyamide inks (1) to (4).

[Comparative Example 1]
Except for using 10.0 parts of CIPigment Red 146 without using a dispersant, the same operation as in Examples 1 to 4 was performed to prepare a polyamide ink for gravure to which no dispersant was added.

[Example 5 (Preparation of pigment composition (1))]
Add 19.0 parts of CIPigment Red 146 to 1,000 parts of water and disperse to make a slurry. Thereto is added a slurry of 1.0 part of the dispersant (A) obtained in Synthesis Example 1 and 0.1 part of caustic soda in 50 parts of water. The mixed slurry is heated to 70 ° C. and the pH is corrected to 4-5. After stirring for 20 minutes, it was filtered, dried and pulverized to obtain 19.9 parts of the pigment composition (1) of the present invention.
Gravure polyamide ink (5) was prepared in the same manner as in Example 1 except that 10.0 parts of the pigment composition (1) was replaced by the total amount of the pigment and dispersant in the formulation (1) of Example 1. did.

[Examples 6 to 8 (Preparation of pigment compositions (2) to (4))]
The same operations as in Example 5 were repeated except that the dispersants (B) to (D) obtained in Synthesis Examples 2 to 4 were used in place of the dispersant (A), respectively, and the pigment compositions (2) to (2) to (4) was obtained. The total amount of the pigment and the dispersant in the formulation (1) of Example 1 is replaced with 10.0 parts of the above pigment compositions (2) to (4), respectively, and the rest is the same as in Example 1 except for the polyamide ink for gravure (6) to (8) were produced.

The viscosity of the polyamide ink for gravure of Examples 1 to 8 and the gloss of the color development surface coated with the ink were compared with those of the ink of Comparative Example 1. The viscosity of each ink and the gloss of the color development surface were measured according to the following method, and were compared with the ink of Comparative Example 1.
Viscosity: measured using a B-type viscometer at room temperature (25 ° C.) and 30 rpm.
Gloss: A bar coater (winding thickness: 0.15 mm) was used to develop color on a polypropylene film, and the gloss of the developed surface was compared visually and with a gloss meter. In addition, the thing with high gloss was made favorable and was described with the following parameter | index.
○: Good Δ: Slightly good ×: Poor The results are shown in Table 1.

  As shown in Table 1, excellent pigment dispersion effects were observed in the inks (1) to (8) of Examples 1 to 8 to which the pigment dispersants (A) to (D) of the present invention were added. Even when the viscosity of these inks (1) to (8) was measured after standing for 1 week, almost no increase in viscosity was observed compared to the ink of Comparative Example 1. Further, not only as a pigment composition but also when a mixture obtained by separately adding a pigment and a dispersant to a vehicle was mixed and dispersed, the effect of a sufficient pigment dispersant was obtained as described above.

[Examples 9 to 12 (Pigment compositions (5) to (8))]
The same procedure as in Example 5 was repeated except that a diketopyrrolopyrrole pigment (CIPigment Red 254) was used instead of CIPigment Red 146, and each of dispersants (A) to (D) was used. ) To (8) were obtained.

[Examples 13 to 16 (pigment compositions (9) to (12))]
The same procedure as in Example 5 was repeated, except that copper phthalocyanine green pigment (CIPigment Green 36) was used instead of CIPigment Red 146, and dispersants (A) to (D) were used, respectively, and pigment composition (9) To (12) were obtained.

In order to evaluate the effect of the dispersant using each of the above pigment compositions (5) to (12), a gravure urethane ink having the following composition (2) was prepared.
Formula (2)
-Pigment composition (5)-(12) 10.0 parts-Nitrified cotton varnish 5.0 parts-Polyurethane varnish 35.0 parts-Thinner 50.0 parts Add the above ingredients into a container and add steel balls. It was dispersed with a paint conditioner to prepare Examples 9 to 16 urethane inks for gravure (9) to (16).

[Comparative Examples 2 and 3]
In place of the pigment compositions (5) and (9), the dispersant was not used in the same manner as in Examples 9 and 13, except that CIPigment Red 254 (Comparative Example 2) and CIPigment Green 36 (Comparative Example 3) were used. Two kinds of urethane inks for gravure were prepared.

  The viscosity and color development gloss of the inks of Examples 9-16 were compared with those of the inks of Comparative Examples 2 and 3. The gloss of the color development surface and the viscosity of the ink were measured in the same manner as in the case of the polyamide ink for gravure, and the relative evaluation was performed as in the case of the inks of Comparative Examples 2 and 3. The results are shown in Table 2.

  As shown in Table 2, as in the case of the gravure polyamide ink, when any of the pigment dispersants (A) to (D) of the present invention is added, a dispersion effect is recognized although there is a slight difference. It was. Even when the viscosity of the ink of the example was measured after standing for 1 week, an increase in the viscosity was hardly observed as compared with the case of the ink of the comparative example.

[Examples 17 to 20 (Preparation of pigment compositions (13) to (16))]
The same procedure as in Example 5 was repeated except that CIPigment Red 177 was used instead of CIPigment Red 146, and dispersants (A) to (D) were used as dispersants, respectively, and pigment compositions (13) to (16 )

Using these pigment compositions (13) to (16), paints having the following formulation (3) were prepared in order to evaluate the effect of the dispersant.
Formula (3)
・ Pigment composition (13) to (16) 6.0 parts ・ Acrylic varnish 46.6 parts ・ Melamine varnish 20.0 parts ・ Thinner 30.0 parts Put the above ingredients in a container and add glass beads. A paint was prepared by dispersing with a paint conditioner.

[Comparative Example 4]
A paint having no dispersant added thereto was prepared in the same manner as in Example 17 except that 10.0 parts of CIPigment Red 177 was used instead of 10.0 parts of the pigment composition (13).

The viscosities of these paints, and color development and gloss of the coated surface after baking were compared with those of the comparative paints. The viscosity of the paint and the gloss of the color development surface were measured according to the following method, and were compared with the paint of the comparative example.
Viscosity: measured using a B-type viscometer under conditions of room temperature (25 ° C.) and 30 rpm.
Gloss: Using an applicator (6 mils), the gloss of the coated surface after color development and baking on an art paper was compared visually and with a gloss meter. In addition, the thing with high gloss was made favorable and displayed with the following parameter | index.
○: Good Δ: Slightly good ×: Poor Table 3 shows the above results.

  As shown in Table 3, the effect of the pigment dispersant of the present invention was recognized as in the above results. Although the paint of the above example was a light-colored paint diluted with a white paint made of titanium oxide to a concentration of 1/10 and observed the aggregation state of the pigment, no color separation or sedimentation of the pigment was observed. It was.

[Examples 21 to 24]
In order to evaluate the effect of the dispersant using the pigment compositions (1) to (4), a color filter colorant having the following composition (4) was prepared.
Formula (4)
Pigment composition (1) to (4) 20.0 parts Polyacrylic acid resin 30.0 parts Thinner 50.0 parts Add the above ingredients into a container, add zirconia beads and disperse with paint conditioner, A color filter colorant was prepared.

[Comparative Example 5]
Pigment composition (1) A color composition for color filter to which no dispersant was added by performing the same operation as in Example 21 except that 20.0 parts of CIPigment Red 146 was used instead of 20.0 parts. Was made.

The fluidity of the colorant for color filter and the gloss of the color development surface of the examples and comparative examples were compared with those of the comparative example. The flowability of the colorant and the gloss of the color development surface were measured according to the following method, and the relative evaluation was made with the comparative example.
Fluidity: Measured using a B-type viscometer under conditions of room temperature (25 ° C.) and 30 rpm.
Gloss: Using a bar coater (winding thickness: 0.45 mm), the film was developed on a polypropylene film, and the gloss of the developed surface was compared visually and with a gloss meter. In addition, the thing with high gloss was made favorable and was described with the following parameter | index.
○: Good Δ: Slightly good ×: Poor Table 4 shows the above results.

  As shown in Table 4, the colorant using the pigment dispersant of the present invention showed higher fluidity than the comparative example, and the effect of the pigment dispersant of the present invention was recognized.

  Furthermore, the pigment added with the pigment dispersant of the present invention was used for printing inks such as offset inks, various paints such as nitrocellulose lacquers and melamine alkyd paints, and coloring synthetic resins such as vinyl chloride resins. In this case, the pigment did not aggregate and showed good dispersibility. In addition, recently, the pigment dispersant of the present invention was used for the production of dry toner or wet toner for electrophotography, ink for ink jet recording, ink for thermal transfer recording, ink for writing instruments, etc., for which high dispersibility is particularly required. Even in these cases, the effect of excellent dispersibility by the pigment dispersant of the present invention was recognized.

  The pigment dispersant of the present invention is used for printing ink (offset ink, gravure ink, etc.), various paints, plastic, pigment printing agent, electrophotographic dry toner or wet toner, ink jet recording ink, thermal transfer recording ink, color filter. For all the vehicles in each application such as resist, ink for writing instruments, etc., in all pigments including organic pigments and inorganic pigments, the fluidity of inks and paints is remarkably improved, and aggregation of pigment particles is prevented. A colored article exhibiting excellent gloss and sharpness can be provided.

Claims (9)

A pigment dispersant comprising a compound represented by the following general formula (I):

(In the formula (I), R ₁ , R ₂ and R ₃ may be the same or different and are a hydrogen atom, a halogen atom or an alkyl group, and M is a hydrogen atom, a metal, an ammonium group or an amine group. , N is the average number of introduced sulfone groups, and is a number from 0.1 to 3.)   A pigment composition comprising a pigment and a dispersant, wherein the dispersant is the pigment dispersant according to claim 1.   The pigment composition according to claim 2, wherein the mixing ratio of the dispersant is 0.05 to 40 parts by mass with respect to 100 parts by mass of the pigment.   The pigment composition according to claim 2, wherein the pigment is an organic pigment.   Pigment is CIPigment Red 146, CIPigment Red 177, CIPigment Red 208, CIPigment Red 242, CIPigment Red 254, CIPigment Red 255, CIPigment Yellow 138, CIPigment Yellow 139, CIPigment Yellow 150, CIPigment The pigment composition according to claim 2, which is a pigment selected from Yellow 185, CIPigment Green 7 and CIPigment Green 36.   The pigment composition according to claim 2, which is a colorant for gravure printing ink.   The pigment composition according to claim 2, which is a paint colorant.   The pigment composition according to claim 2, which is a colorant for a color filter.   The colorant for a color filter according to claim 8, wherein the pigment composition according to claim 2 is contained in the photosensitive resin varnish.