JP2020059844A - C.i. pigment yellow 155 and method for producing the same, pigment composition and colorant composition including the pigment, and use of them as colorant - Google Patents

Abstract

To provide an azo pigment C.I. pigment yellow 155 that has high affinity with binder resin and has, therefore, excellent image fixability or the like, and facilitates handling of a pigment dispersion in an organic solvent, and a method of producing the same.SOLUTION: The present invention provides a C.I. pigment yellow 155 in which a pigment powder has a methanol wettability (MW value) of 10% or less and 2% or more.SELECTED DRAWING: None

Description

  The present invention has a suitable hydrophobic property, and is excellent in handling property and image fixing performance in the colorant manufacturing process. I. Pigment Yellow 155.

An image forming / displaying method by a color-reducing method such as printing ink, paint, toner and ink jet is generally performed by a combination of three primary colors of yellow (Y), magenta (M) and cyan (C). The following characteristics are required for each of the pigments for such three primary colorants.
1) High color rendering performance displayed by hue, saturation, brightness, etc. 2) Excellent manufacturability 3) Image quality and durability on printed paper

  Regarding the first color rendering performance, when printing an image represented on a color display with a color printer, the color reproduction area (YMC color space) of the printer ink is smaller than the color reproduction area (RGB color space) on the color display. The image is apt to lack clarity because it is narrow. One of the causes is that the lightness and saturation of the pigment are low, and its improvement has been widely promoted.

  Regarding the second manufacturability, the pigment needs to satisfy various physicochemical properties in order to manufacture an ink or a toner. For example, it is necessary that the pigment dispersion has an appropriate viscosity. Further, in the case of producing a toner by an emulsion polymerization method as disclosed in Patent Document 1, it is necessary to have appropriate surface characteristics such that a monomer can be adsorbed on the pigment surface.

  As the quality on the third printing paper, in addition to color image performance, light resistance and strong affinity with a resin binder for obtaining physical strength such as abrasion resistance are also required.

  In order to meet the above needs, pigments have been conventionally improved in each hue. For example, with respect to yellow pigments, many azo pigments have been developed because there is a wide range of choices for producing pigments, which makes it relatively easy to control the color rendering properties such as hue, and has excellent production suitability. ing. As such an azo pigment, the azo pigment having a plurality of azo groups in the molecule has a large color strength and, as a result, a large molecular weight, and hence a high cohesiveness, which is also preferable for light resistance. Has been developed. In that case, many pigments having a molecular structure in which each azo group exists in a symmetrical position in the molecule have been developed because the absorption spectrum width can be reduced and the sharpness can be easily improved. . For example, in Patent Document 2, C.I. I. Pigment Yellow 155 is described.

  C. I. Although a molecular structure such as Pigment Yellow 155 is preferable in order to have high color rendering properties, it is not always preferable in view of manufacturing suitability and image strength. For example, C.I., which is an azo pigment having two azo groups in symmetrical positions as described above. I. When Pigment Yellow 155 is dispersed in a solvent, its viscosity becomes very high even without a binder. Therefore, even if a monomer is added to an aqueous dispersion of a pigment to carry out emulsion polymerization, uniform stirring is difficult, and as a result, it is difficult to obtain a toner having uniform performance.

  Since the viscosity is high even in a system in which no resin is present as described above, the viscosity is further increased when a binder resin is added for the purpose of making a resist for an inkjet ink or a color filter, for example. Such a high-viscosity pigment dispersion makes proper dispersion (adjustment of pigment particle size and its distribution) difficult, and requires a large-scale dispersion device and long-time dispersion work. It is a heavy burden for manufacturing. Further, if the viscosity of the pigment dispersion liquid is too high and it becomes difficult to eject the ink from the inkjet head, or if the dispersion is poor, coarse pigment particles remain, which tends to cause poor image quality and clogging of the inkjet nozzle. There is.

  From the above background, various ideas such as changing the type of solvent and lowering the pigment concentration have been conventionally made in order to reduce the viscosity of the pigment dispersion liquid, but the reality is that it has not fully responded. .

  As described above, C.I. I. Pigment Yellow 155 has a strong need to reduce the viscosity of its dispersion. C. which results in the low viscosity of such dispersions. I. When Pigment Yellow 155 can be manufactured, it will be possible to replace conventional electrophotographic toners and ink jet ink pigments and obtain color images having more vivid colors at low cost. Moreover, if the C ink of the conventional process ink C, M, Y, K ink can be replaced with a highly saturated one, it is possible to use many colorants such as a coloring agent for a secondary color with high saturation such as green. Expected to be used.

JP, 2006-309035, A Patent 3917764

  The first object of the present invention is to provide C.I. I. For Pigment Yellow 155, by adjusting the viscosity of the dispersion liquid to an appropriate range, the operability and handleability during the production of the colorant using the pigment are improved, and the uniformity of the quality of the colorant, It is to improve reproducibility. Further, in the course of reaching the present invention, when the image using the pigment produced according to the present invention was evaluated, the result was that the strength might be relatively low. Therefore, the present invention aims to prevent the decrease in the image strength. Providing a possible pigment was another additional task. Other problems of the present invention will be apparent to those skilled in the art from the following description.

In view of the above situation, the present inventors have earnestly studied to solve the drawbacks of the prior art, and have obtained the following guidelines in order to solve the problems of the present invention.
(1) The cause of the high viscosity of the pigment dispersion was initially thought to be the interaction between the pigment and the resin. However, since the dispersion exhibits a high viscosity even if the resin is removed, it is believed that the pigment particles are dispersed between the pigment particles and / or the pigment. -The interaction between solvent molecules was estimated to be large.
(2) The crystal morphology was observed by an electron microscope to investigate the cause, and it was found that the crystals were fine and elongated needle-like crystals.
(3) It is expected that the interaction between the crystal particles is strong due to the needle-like shape and that the interaction between the crystal and the solvent is large due to the large surface area. Either or both of them are dispersed. It was presumed that the viscosity of the liquid was increased.
(4) Then, various methods for reducing the interaction between the pigment particles and between the pigment and the solvent were investigated. The specific policy is to change the shape of the pigment particles from a needle shape to reduce the aspect ratio, to increase the pigment particle size, and further to change the properties of the pigment surface between the particles or between the particles and the solvent. The change is to reduce the interaction.
(5) Using the above as a guide, various conditions were mainly studied for the steps after the azo coupling reaction. As a result, a finishing treatment with a high-boiling point solvent was performed after the pigment was prepared, whereby a pigment satisfying the above needs could be obtained. It was
(6) Analysis of the reason revealed that the shape of the crystal of the pigment changed due to finishing, and at the same time, its growth proceeded and the crystal size increased.
(7) Due to such crystal shape change and particle growth, it is presumed that the contact between particles becomes small and the interaction between the pigment and the solvent becomes small.
(8) When the thus-prepared pigment was mixed with a resin and a solvent, it was confirmed that a low liquid viscosity could be achieved and the handling property of the dispersion liquid was improved.
(9) The colorant dispersion thus obtained was applied to a printing paper, and the dried film was evaluated. The frictional strength of the colorant film (corresponding to pixels in printing) of the printing paper depending on the pigment finishing conditions. It has been found that (correlation with fixability) may be relatively low. It was expected that the cause of the low frictional strength was a decrease in the adhesion between the coating film and the paper and a decrease in the adhesion between the resin and the pigment particles.
(10) Then, as a result of examining the cause of the low image strength by observing with a microscope, it was determined that the adhesiveness between the pigment and the resin was the main factor. Since the resin is a highly hydrophobic resin, it was expected that the change in the adhesion between the pigment and the resin was due to a decrease in the hydrophobicity of the pigment surface, an increase in the hydrophilicity, or a change in the surface area.
(11) Then, as a result of searching means for quantifying the pigment particle surface characteristics, the measured value (MW value) by the methanol wettability method described later grasps the surface characteristics of the pigment of the present invention and It has been found to be a good way to control. It was found that not only the viscosity of the pigment dispersion liquid can be controlled but also the frictional strength of the image can be controlled by setting the MW value in an appropriate range.
(12) That is, by adjusting the finishing condition of the pigment so that its MW value is not more than a specific value, the pigment dispersion viscosity is lowered, and additionally, by making the MW value not less than a specific value. It has been found that a pigment coating film having improved frictional strength can be obtained.
Based on the above guidelines, focusing on the finishing conditions for azo pigments, there is an effect of reducing the viscosity of the pigment dispersion liquid, and further search for conditions such as the manufacturing method of Pigment Yellow 155 that can improve the image strength on printing paper. I went.

That is, the present invention
1. Pigment Yellow 155 whose powder has a methanol wettability (MW value) of 10% or less,
2. Pigment Yellow 155 of 1 above, in which the powder has a methanol wettability (MW value) of 2% or more.
3. Pigment Yellow 155 according to 1 or 2 above, which has a primary particle diameter of 50 nm to 300 nm and an aspect ratio of 1 to 10 according to the TEM method.
4. Pigment Yellow 155 described in 1 to 3 above, wherein the primary particle diameter by TEM method is 50 to 250 nm, and the aspect ratio of the pigment is in the range of 1 to 7.
5. Pigment Yellow 155 according to 1 to 4 above, wherein the residual content of the organic solvent is less than 500 ppm,
6. Pigment Yellow 155 according to the above 5, wherein the residual content of the organic solvent is less than 100 ppm,
7. Pigment Yellow 155 of 5 or 6 above, wherein the organic solvent has an boiling point of 95 ° C. or higher,
8. Pigment Yellow 155 of 5 to 7 above, wherein the organic solvent is a linear, branched or cyclic C3 or more saturated or unsaturated monohydric or polyhydric alcohol solvent,
9. The alcohol solvent is selected from the group consisting of 1-propanol, 1-butanol, 2-butanol, isobutanol, 1-pentanol, 2-pentanol, 2-hexanol, 1-heptanol, 2-heptanol, ethylene glycol and glycerin. Pigment Yellow 155 of 8 above, which is one or more solvents selected.
10. Pigment Yellow 155 described in 5 to 9 above, wherein the organic solvent is a finishing solvent used in the manufacturing process.
11. Pigment Yellow 155 of the above 1 to 10, other coloring pigments, and / or a pigment composition containing a yellow fluorescent dye,
12. Other coloring pigments are C.I. I. Pigment Yellow 74, C.I. I. Pigment Yellow 120, C.I. I. Pigment Yellow 151, C.I. I. Pigment Yellow 180, C.I. I. Pigment Yellow 185, C.I. I. Pigment Yellow 194, C.I. I. Pigment Yellow 198, C.I. I. Pigment Yellow 213, C.I. I. Pigment Yellow 214, C.I. I. Pigment Yellow 217, which is one or more pigments selected from the group consisting of Solvent Yellow 33, Solvent Yellow 98, Solvent Yellow 131, Solvent Yellow 135, and Solvent Yellow 160: 1. 11. The pigment composition according to 11 above, which is one or more dyes selected from
13. Pigment Yellow 155 described in 1 to 10 above, a colorant composition containing at least a polymer and a wax,
14. A colorant composition containing at least the pigment composition of 11 or 12, a polymer and a wax;
15. A method for producing Pigment Yellow 155 according to 1 to 10 above,
1) Azo pigment synthesis process by coupling reaction of diazonium compound in aqueous solution,
2) Finishing treatment step of an azo pigment with an alcohol solvent having a boiling point of 95 ° C. or higher,
Including a pigment manufacturing method,
16.
1) Azo pigment synthesis process by coupling reaction of diazonium compound in aqueous solution,
2) Finishing treatment step of an azo pigment with an alcohol solvent having a boiling point of 95 ° C. or higher,
Including,
A method for producing the pigment composition according to the above 11 or 12, wherein another pigment and a fluorescent dye are added before or after the finishing,
17． The alcohol solvent having a boiling point of 95 ° C. or higher is one or more selected from the group consisting of linear, branched or cyclic, saturated or unsaturated monovalent or polyvalent alcohols having 3 to 8 carbon atoms. The method of 15 or 16 above, which is a solvent of
18. The method according to the above 15 to 17, wherein the finishing treatment step is carried out by contacting, preferably mixing, the synthesized azo pigment and the organic solvent at a temperature 0 to 100 ° C. higher than the boiling point of the organic solvent for 10 minutes or more. ,
19. Use of Pigment Yellow 155 described above in 1 to 10 as a colorant or for image forming applications,
20. Use of the azo pigment composition according to the above 11 or 12 as a colorant or for image forming applications,
Is.

  According to the present invention, the viscosity of the pigment dispersion liquid can be reduced by setting the methanol wettability value (MW value) of the pigment to a specific value or less. Further, by setting the MW value to be a specific value or more, the rubbing durability of the coloring material can be improved. From these results, it is possible to provide a coloring material having excellent manufacturing suitability in the coloring material manufacturing process and excellent physical strength of an image. The colorant using the present pigment can be used not only for various image forming applications such as printing inks, toners and inkjet inks, but also for other applications such as paints.

Electron microscope (TEM) photograph showing the pigment form of Example 2 (11,000 times) The electron microscope (TEM) photograph (11,000 times) which shows the pigment form of the comparative example 1 (no finishing process). Very fine needle-like crystals are mixed with large granular pigment particles that are not sufficiently dispersed.

  The azo pigment of the present invention contains two or more azo groups at symmetrical positions in the molecule and has a value (MW value) of 10 or less by a methanol wettability measurement method described later, and more preferably a MW value of 2 or less. The above is the azo pigment.

  Azo pigments that can be used in the present invention include C.I. I. Pigment Yellow 155.

  The C.I. I. Pigment Yellow 155 (PY-155) (azo groups on both sides of phenylenediamine), which are excellent as azo pigments for image formation, include those having two or more azo pigments at symmetrical positions in the molecule. is there. Its molecular shape is narrower than that of phthalocyanine pigments. Such elongated molecules tend to become acicular when crystallized, which is accompanied by an increase in surface area. Since the particle surface of such a pigment changes depending on the crystal structure or the like, it is considered that, for example, when a large polar group is present in the molecule, its hydrophobicity is also affected by the crystal structure.

  Further, in the case of pigment particles having an elongated molecular structure, the contact between particles increases as the pigment concentration in the dispersion increases, and since the surface area is large, the viscosity of the dispersion due to the interaction with the solvent and the interaction between the particles. Easy to increase. As a result, the viscosity of the pigment dispersion increases, the handling property in the colorant manufacturing process using the pigment dispersion is significantly reduced, mass production becomes difficult, and the cost is likely to increase.

  The increase in viscosity of the pigment dispersion as described above can be solved by the azo pigment according to the present invention having a methanol wettability value (MW value) adjusted to 10% or less. When the MW value exceeds 10%, the viscosity of the pigment dispersion liquid increases as shown in Examples and Comparative Examples described later, so that even if the pigment dispersion is carried out for a long time, uniform dispersion becomes difficult and large pigment particles are generated. It is not preferable because it tends to remain and causes deterioration of performance such as deterioration of image strength due to a scratch test.

  The MW value of the azo pigment of the present application is preferably 2% or more. As the MW value becomes smaller, the image strength tends to decrease by the rubbing test, as will be seen in the examples described later, and when the MW is less than 2%, the strength sharply decreases.

  Considering both performances in terms of lowering the viscosity of the dispersion and improving the image strength, the preferable range of MW is 3% to 7%.

  The method for measuring the methanol wettability (MW value) of the pigment in the present invention is to increase the affinity between water and the pigment by adding methanol to the water in which the pigment is suspended, as will be described later. In this method, the pigment is allowed to settle and the amount of methanol added at that time is measured. Since a pigment having a large hydrophobicity has a low affinity with water, the pigment is not sufficiently wetted with water and is in a state of being suspended due to the surface tension of water. When methanol is added thereto, hydrophilicity of water is lowered and surface tension is lowered, so that affinity with the pigment is increased. When the added amount of methanol exceeds a specific value, gravity becomes larger than buoyancy due to the surface tension, and the pigment comes to settle. The methanol wettability value is a value obtained by measuring the amount of methanol added until the hydrophobic pigment settles (volume of methanol added to 100 ml of water), expressed in%.

  One of the objects of the present invention is to reduce the viscosity of a pigment dispersion liquid by using a pigment prepared by a conventional method known as a method suitable for toner application, and having a MW value below a specific value by a finishing treatment. Is achieved by setting the content to 10% or less.

  Finishing in the production of azo pigments is a final treatment step performed for the purpose of further improving the hue, light resistance, etc. of the pigment synthesized by the coupling reaction, and each pigment is subjected to a method according to the purpose. There is.

  C. I. In the case of Pigment Yellow 155, there are two conventional methods of washing with water after the azo coupling reaction, drying and then using as it is without finishing, and treating with a high boiling point, high polar solvent such as DMF. Came.

  In the present invention, the viscosity of the pigment dispersion liquid is considered to be greatly influenced by the particle size and shape thereof, and the finishing treatment was studied as a means for controlling them. Specifically, we examined various finishing solvents and searched for conditions such as heating temperature and time. As a result, they have found that it is preferable to use an alcohol solvent having a boiling point of 95 ° C. or higher, instead of a conventionally known general solvent. The reason for this is unknown, but it is surmised that a solvent must have an appropriate balance of hydrophilicity and hydrophobicity in order to make the surface of the pigment hydrophilic.

  The finishing solvent of the present invention is preferably an alcohol having a boiling point of 95 ° C. or higher, and more specifically, a linear, branched or cyclic, saturated or unsaturated monovalent or polyvalent carbon atom. Alcohols of the number 3 to 8, preferably 4 to 7, such as 1-propanol, 1-butanol, 2-butanol, isobutanol, 1-pentanol, 2-pentanol, 2-hexanol, 1-heptanol, 2-to. It is possible to use one of phthalanol, ethylene glycol, glycerin, or a solvent in which a plurality of them are mixed. Among them, a branched and saturated monohydric alcohol, especially isobutanol (boiling point: 108 ° C.) is particularly preferable. It is also possible to mix and add another solvent such as a ketone solvent or an ether solvent to these alcohols.

  The finishing treatment of the present invention is carried out by putting pigmented Pigment Yellow 155 and the finishing solvent in a container and heating them, as will be shown in Examples described later. Pigment Yellow 155 to 10 parts by weight, preferably 10 to 100 parts by weight of a finishing solvent is added. If the amount of the finishing solvent is less than 10 parts by weight, the finishing treatment may not be sufficiently and uniformly carried out, and if it exceeds 100 parts by weight, the growth of the particle crystals is too fast and the particle size control becomes difficult, which is not preferable.

  By setting the heating temperature of the finishing treatment to be equal to or higher than the boiling point of the finishing solvent, the finishing treatment time can be shortened. The heating temperature is usually 0 to 100 ° C. higher than the boiling point of the finishing solvent, and more preferably 10 to 80 ° C. higher than the boiling point of the finishing solvent. If the temperature difference from the boiling point is less than 0 ° C., it takes a long time to finish, and if it exceeds 100 ° C., side reactions such as decomposition of the pigment are likely to occur, and a pressure resistant container is required, which is not preferable.

  The finishing treatment time of the present invention varies greatly depending on the heating temperature, but is usually 10 minutes or longer, preferably 20 minutes to 15 hours, and particularly 20 minutes to 5 hours. If the time is short, the finishing tends to be uneven. There is no particular upper limit, but if it exceeds 15 hours, the manufacturing cost becomes high, which is not preferable.

  The azo pigment having the methanol wettability falling within the scope of the present invention may be produced by the conventional method described in the above-mentioned patent documents, and the finishing treatment may be performed in the last step. Alternatively, instead of the finishing treatment, the methanol wettability may be adjusted by treatment such as salting out at the stage of insolubilization after azo synthesis and pigmentation.

  The pigment that has been subjected to the finishing treatment is subjected to necessary treatments such as washing with water, drying, and pulverization, and then used for the next step.

C. of the present invention I. Pigment Yellow 155 also changes the pigment primary particle diameter, BET surface area, and aspect ratio depending on the finishing conditions. As the MW value becomes smaller than 12%, the degree of correlation is not high, but the general tendency is that the primary particle size increases, the surface area decreases, and the aspect ratio increases. The primary particle size is preferably 50 nm to 300 nm, particularly preferably 50 to 250 nm, the BET surface area is preferably 25 to 100 m ² / g, and the aspect ratio is preferably in the range of 1 to 10, particularly preferably in the range of 2 to 7. is there.

In order to make the primary particle diameter smaller than 50 nm, it is necessary to disperse for a long time, and the dispersion liquid tends to have high viscosity and gelation. If the BET surface area is less than 25 m ² / g, the particle size is too large, and the coloring power is likely to decrease, and if it exceeds 100 m ² / g, the viscosity of the dispersion increases, which is not preferable. Regarding the aspect ratio, when the aspect ratio exceeds 10 and becomes large like the above-mentioned needle-like crystal, the viscosity rapidly increases, and the dispersion becomes poor, and the coloring power and the image quality are likely to be deteriorated. The theoretical lower limit of the aspect ratio is 1, but no significant deterioration in performance has been observed even if the aspect ratio is reduced to 2 or less.

  C. of the present invention I. The performance of Pigment Yellow 155 can be affected by the concentration of residual solvent in the pigment. The organic solvent may remain in the pigment due to the solvent used for synthesizing the pigment, the finishing solvent, or the like. As shown in a comparative example described later, when the residual solvent concentration becomes high, the image strength by the rubbing test may decrease. A preferable range of the residual solvent concentration is 500 ppm at the maximum, particularly preferably 100 ppm at the maximum, and particularly 50 ppm at the maximum. If it exceeds 500 ppm, side effects such as reduction in image strength are likely to occur. The lower limit is not particularly limited, but may be, for example, 0.5 ppm because it is not preferable in terms of cost because it requires a long time for drying.

  The pigment of the present invention may be used by adding two or more kinds of coloring materials depending on its use and need. Such a coloring material is used for the purpose of changing the saturation, brightness, or hue angle of the yellow pigment of the present invention. The C. I. Pigment Yellow 155 can be used in combination with other pigments or dyes.

  There are various pigments that can be used in combination with Pigment Yellow 155 of the present invention. For example, when used in combination with Pigment Yellow 155 as a yellow hue, another yellow pigment Y2 may be C.I. I. Pigment Yellow 74, C.I. I. Pigment Yellow 120, C.I. I. Pigment Yellow 151, C.I. I. Pigment Yellow 180, C.I. I. Pigment Yellow 185, C.I. I. Pigment Yellow 194, C.I. I. Pigment Yellow 198, C.I. I. Pigment Yellow 213, C.I. I. Pigment Yellow 214, C.I. I. Pigment Yellow 217 and the like are exemplified.

  The pigment to be combined with Pigment Yellow 155 is not limited to a yellow pigment. When it is desired to express green by combining with a blue pigment, Pigment Yellow 155 and a cyan pigment, for example, C.I. which is a phthalocyanine blue pigment. I. It is also possible to use a combination of at least one pigment selected from Pigment Blue 15: 3, Pigment Blue 15: 1, Pigment Blue 15: 2, Pigment Blue 15: 4, and Pigment Blue 15: 6.

  The composition ratio of the pigment to be combined with Pigment Yellow 155 greatly varies depending on the intended hue and application, and therefore cannot be determined unconditionally, but for example, Pigment Yellow 155 is 100 parts by weight relative to other pigments. Can be used in the range of 1 to 200 parts by weight. If the amount of the other pigment is less than 1 part by weight, the effect of the combination cannot be expected sufficiently. On the other hand, when the amount of the other pigment exceeds 200 parts by weight, the hue of Pigment Yellow 155 is largely deviated, and characteristics such as high saturation are easily lost.

  Another preferred coloring material for use with the pigments of the present invention is a fluorescent dye. Fluorescent dyes, especially yellow fluorescent dyes, have a high ability to emit yellow to green fluorescence, and thus can significantly enhance the saturation of the colorant. Further, the yellow fluorescent dye is preferably used when improving the saturation of the yellow pigment and shifting it to a bluish yellow, and the details thereof are described in Japanese Patent Application No. 2014-157613 by the present inventor. ing.

  The fluorescent dye has a maximum wavelength of 490 to 490 in the reflection spectrum measurement described later in Patent Application No. 2014-157613 described above when the coating film is formed using only this fluorescent dye and a resin. It is preferably in the range of 550 nm and the maximum reflectance thereof is 90% or more. The maximum reflectance in the same wavelength range when fluorescent dyes do not coexist is about 20 to 80%, and the difference between this reflectance and the reflectance of a system containing fluorescent dyes of 90% or more is high for human vision. You will feel the degree and blueness.

  The yellow fluorescent dye preferably has the above-mentioned reflection spectrum characteristic of 130% or less in the above-mentioned wavelength range. A reflectance of more than 130% is not preferable because the color difference due to vision becomes large due to the color temperature difference of the light source.

  Examples of the yellow fluorescent dye used in the present invention include perylene-based, fluorocein-based, benzothiazole-based, benzimidazole-based, benzoxazole-based, rubrene-based, stilbene-based compounds, biphenyl-based, pyrazoline-based, coumarin-based, and naphthalimide-based dyes. , Oxazoline dyes, pyranine dyes and the like. Many of such dyes are classified as oil-soluble dyes, disperse dyes, water-soluble dyes, etc., and are appropriately selected and used from them.

  In the present invention, the yellow fluorescent dye includes C.I. I. Solvent Yellow 33, 98, 131, 135, and 160: 1 oil-soluble dyes such as C.I. I. Disperse dyes such as Disperse Yellow 82, C.I. I. Water-soluble dyes such as Basic Yellow 40 are particularly preferably used.

  In the present invention, the fluorescent dye may be used in a composition of 0.05 to 30 parts by weight with respect to 100 parts by weight of Pigment Yellow 155 pigment. If it is less than this range, the effect of improving the saturation is small, and if it is more than this range, side effects such as a large color difference due to a difference in light source become large.

  A more preferred composition of the fluorescent dye of the present invention and Pigment Yellow 155 pigment is 0.1 to 20 parts by weight, more preferably 0.1 to 20 parts by weight, and more preferably 0.1 to 100 parts by weight of Pigment Yellow 155 pigment. 10 to 10 parts by weight. The range within these ranges is preferable from the viewpoint of reducing the color difference ΔE under light sources having different color temperatures.

  The pigment of the present invention is mainly used as a constituent component of a colorant composition for image formation. The method for producing the colorant composition varies greatly depending on its use. For example, a dry toner for electrophotography is mixed with a solvent and a binder resin, dried, and then pulverized. In the case of an inkjet ink, water or an organic solvent, a resin, and necessary additives are added and dispersed.

  The resin used in combination with the pigment of the present invention is not particularly limited, but in the case of an image forming application, a hydrophobic resin is generally preferably used in order to enhance the mechanical strength and water resistance of the image. As such a resin, various resins such as polyester resins, acrylic resins, polyolefin resins, styrene resins, rubber resins, polyamide resins and urethane resins can be appropriately selected and used. Among these, polyester, acrylic, styrene-acrylic, and urethane resins are particularly preferable.

  The resin used in combination with the pigment of the present invention is not limited to the above-mentioned thermoplastic resins, and for example, a polyfunctional acrylic resin, an epoxy resin, or a curable resin that three-dimensionally crosslinks by light or heat is also used. It can be used according to.

  The composition of the pigment and the resin in the colorant composition of the present invention varies greatly depending on the application, but generally 0.5 to 30 parts by weight, preferably 1 to 15 parts by weight of the pigment per 100 parts by weight of the resin. Is. Below this range, it is necessary to increase the film thickness in order to obtain the required degree of coloring, which may deteriorate the drying / fixing performance and the image quality. On the other hand, if the amount exceeds the above range, the mechanical strength, adhesion, etc. of the pixels formed of the coloring material are deteriorated, which is not preferable.

  In addition to the azo pigment and the resin binder, it is possible to appropriately add other materials to the colorant composition of the present invention in order to satisfy the functions and physical properties required for the application. As such an additive, a pigment dispersant, an ultraviolet absorber for improving light resistance, a surfactant for improving coatability, a tackifier for improving adhesion with a substrate, and the like. There are waxes and the like for controlling the thermal characteristics and surface characteristics of the colored coating film. In the case of printer toner, it is preferable to add a charge control agent for controlling electrostatic characteristics. Further, the addition amount of the above-mentioned additive is added within a range suitable for each application.

Various methods can be used to provide the azo pigment of the present invention, depending on the application and the position of use. For example, 1) an azo coupling reaction is carried out in a reaction vessel, washed with water to remove impurities, dried, and ground, and the azo pigment is subjected to the finishing treatment of the present invention in a separate step, if necessary.
2) After azo coupling, washing with water, substituting water with a low boiling point solvent or the like, and then performing the finishing treatment of the present invention.
3) After azo coupling, washing with water, substituting water with a low boiling point solvent, etc., then adding other coloring pigments or fluorescent dyes, and then performing finishing treatment,
Etc. are possible.

  The former step 1) is suitably performed, for example, when it is desired to have characteristics suitable for the application by adding another pigment or fluorescent dye to the azo pigment once produced and finishing it. In the step 2), since the finishing process is performed after the pigment manufacturing process, the manufacturing cost is reduced. The case of 3) is preferable when it is desired to adjust the characteristics of the pigment with various colorants.

Example 1
Registered Patent Publication No. 3917764 (Patent Document 2) A pigment is prepared by coupling diazotized dimethyl 2-aminoterephthalate with bis (acetoacetylamino) -benzene as described in Example 1, followed by filtration and washing with water. A suspension was obtained. 100 parts by weight of the pigment suspension (pigment concentration: about 20%) is mixed with 500 ml of isobutanol (boiling point: 108 ° C.) in a container, and a finishing treatment of heating at 150 ° C. for 1 hour is performed, followed by distillation, washing with water, The target pigment was obtained by drying.

Example 2
After carrying out the coupling reaction, filtration and washing with water in the same manner as in Example 1, C.I. C. was used under the same conditions as in Example 1 except that the finishing treatment was carried out at 150 ° C. for 30 minutes. I. Pigment Yellow 155 pigment was obtained.

Example 3
After the coupling reaction, filtration and washing with water were carried out in the same manner as in Example 1, C.I. C. was used under the same conditions as in Example 1 except that the finishing treatment condition was 150 ° C. for 2 hours. I. Pigment Yellow 155 pigment was obtained.

Example 4
After carrying out the coupling reaction, filtration and washing with water in the same manner as in Example 1, C.I. C. was used under the same conditions as in Example 1 except that the finishing treatment was carried out at 150 ° C. for 4 hours. I. Pigment Yellow 155 pigment was obtained.

Example 5
The azo coupling reaction, filtration and washing with water were carried out in the same manner as in Example 1, and then C.I. I. Pigment Yellow 180 (manufactured by Clariant, Toner Yellow HG) 100 parts by weight of a pigment press cake is added and mixed, and the crude pigment is heated in isobutanol at 150 ° C. for 2 hours, and then distilled, washed with water and dried to obtain 2 A yellow pigment was obtained in which the different pigments were mixed.

Example 6
The azo coupling reaction, filtration and washing with water were carried out in the same manner as in Example 1. To 100 parts by weight of the finishing untreated pigment press cake (Pigment Yellow 155), 10 parts by weight of a yellow fluorescent dye (CI Solvent Yellow 160: 1, Lanxess, Macrolex Fluorescent Yellow 10GN) was added and mixed. Washed with water. The crude pigment was heated in isobutanol at 150 ° C. for 2 hours, then distilled, washed with water and dried to give C.I. I. Pigment Yellow 155 and a yellow fluorescent dye were mixed to obtain a yellow pigment.

Comparative Example 1
A coupling sample, filtration, water washing, and drying were performed under the same conditions as in Example 1 except that the finishing treatment was not performed, to obtain a pigment sample of Comparative Example 1. As shown in the transmission electron microscope (TEM) photograph of FIG. 2, the particle morphology of this sample is an extremely long and narrow needle-like crystal, and it is clear that its aspect ratio exceeds 10. Since the measurement is difficult, it was difficult to measure the primary particle diameter and the aspect ratio.

Comparative Example 2
A pigment sample of Comparative Example 2 was obtained by the same method and conditions as in Example 1, except that the finishing treatment was carried out by heating in dimethylformamide (boiling point 153 ° C) at 150 ° C for 2 hours.

(Measurement of primary particle size and aspect ratio)
The primary particles are measured by taking a transmission electron microscope (TEM) photograph of the pigment. For this purpose the pigments are dispersed in diethyl ether for 15 minutes and then spray-applied to PET films. Micrographs are taken at 13,000x and 29,000x magnification. The particle diameter, the long diameter and the short diameter of 1000 particles were counted, and the diameter of a circle equivalent to the area calculated from the long diameter and the short diameter was defined as the primary particle diameter.

  Similarly, regarding the aspect ratio, the ratios of the major axis and the minor axis are averaged and described in the table. FIG. 1 is a morphological observation photograph of Pigment Yellow 155 particles of Example 2 at a magnification of 11,000, and FIG. 2 is a morphological observation photograph of Comparative Example 1 (without finishing treatment) under the same conditions.

(Methanol / wetability MW value measurement)
0.1 g of the pigment was placed in a beaker containing 100 mL of ion-exchanged water, and the methanol wettability was measured with a commercially available measuring device WET101P (manufactured by Reska Corp.). The rotation speed of the magnetic stirrer was 200 rpm, and the dropping speed of methanol was 3 ml / min. As a result, the transmittance was measured by injecting laser light into the lower part of the water tank and measuring the laser light intensity on the opposite side of the water tank. Before the addition of methanol, the pigment floats on the water surface, and the laser light transmittance is 100%. However, with the addition of methanol, the pigment begins to settle and the transmittance starts to decrease. In the table, the concentration of methanol when the permeability of the aqueous phase was lower than 95% was measured, and the value was taken as the MW value (for example, if 5 mL of methanol was added to 100 mL of water, if it sedimented, Its MW value is 5%).

(Preparation of sample for dispersion viscosity measurement)
Alkyd-melamine (AM resin) varnish was chosen to evaluate its properties in a water-free solvent system. 3.6 g of pigment, 26.4 g of dispersion varnish, and 140 g of 3 mm glass beads are put in a 150 mL plastic bottle and dispersed for 30 minutes by a paint shaker. Then, 60 g of diluted varnish is added and mixed with a paint shaker for 5 minutes to obtain a dispersion liquid.

The dispersion varnish used has the following composition:
50.0 parts of Viakyd AC451n / 70 SNB (AM resin and additives, Esser-Lacke)
50.0 parts of Solvent Naphtha
The diluted varnish has the following composition:
26.4 parts of Viakyd AC451n / 70 SNB (AM resin and additives, Esser-Lacke)
29.4 parts Viakyd AC 451/60 SNA (AM resin and additives, Esser-Lacke)
35.8 parts Maprenal MF600 / 55BIB (AM resin and additives, Esser-Lacke)
2.17 parts of n-butanol 2.17 parts of Depanol I
1.86 parts butyl diglycol 2.2 parts Solvent Naphtha

(Dispersion viscosity measurement)
For the viscosity, the dependence of the viscosity of the dispersion liquid on the shear rate in the range of 0 to 250 s ⁻¹ was examined by using a Haake cone plate viscometer (Roto Visco 1) (titanium cone: 60 mm diameter, 1 °). Decided by. The viscosity values reported in Table 1 were measured at a shear rate of 250 s ^-1 .

(Method of measuring the content of organic solvent)
Weigh 20 g of 3 mm glass beads into a 100 ml plastic bottle and weigh 3 g of pigment sample. After adding 30 g of tetrahydrofuran thereto and stirring lightly, the mixture is dispersed for 1 hour with a paint shaker. After the dispersion, suction filtration is performed with a 0.2 μm-opening membrane filter to collect the filtrate. The filtrate was analyzed by GC-MS to quantify the organic solvent in the pigment.

(Evaluation method of tinting strength)
0.6 g of pigment, 10 g of polyester resin (Finetone (registered trademark) 382ES, manufactured by Reichhold Chemical Co., Ltd.), and 20 g of solvent (tetrahydrofuran) were weighed and put into a 70 ml glass bottle, and the diameter was 2 mm. 70 g of the glass beads of 1 are weighed and dispersed by a vertical paint shaker for 60 minutes. The finished ink (pigment concentration 6%) was used as a bar coater No. At 2, the color is applied to the coated paper. A hot plate is used for drying after color development. Bar coater No. The wet coating amount when 2 was used was 12 μm. This developed product was subjected to color measurement with a spectrophotometer [SPECTRA FLASH SF600 (manufactured by Data Color International Co.)] with a D65 light source as a measurement light source and a viewing angle of 10 ° to quantitatively determine the coloring power (%). evaluated.

(Evaluation of image strength (rubbing test residual rate))
Using the developed and dried sample prepared by the above-mentioned coloring ability evaluation method, using a scratch tester (Yasda Co., Ltd., Type No. 162 SLIP TESTER), a load of 200 g, 100 reciprocations, against plain paper Abrades the colored coating (printed material) by rubbing. The yellow density of the printed matter before and after the scratch test was measured by a spectroeye (manufactured by GretagMacbeth), and the density residual ratio of the printed matter was calculated and shown in Table 1.
The obtained evaluation results are shown in Table 1.

The results of Table 1 are summarized as follows.
1) Methanol wettability value (MW value) is 10% or less (Example 1), which is a practical viscosity of 400 mPas or less. When the MW value exceeds 10% (Comparative Example 1), the viscosity becomes as high as 700 (dispersion is poor or handling (productivity) problems occur).
2) The image density residual rate by the rubbing test becomes smaller as the MW value decreases. As one of the factors, it was presumed that when the hydrophilicity of the pigment surface was high (small MW value), the affinity with the resin was lowered and the rubbing strength was lowered.
3) The higher the image density residual rate by the rubbing test, the more preferable. Although the allowable lower limit value is not clear, considering the characteristics of other magenta and cyan pigments, a too low value was not forgiven, and the present inventors determined that the lower limit value is 70%. Considering that way, the lower limit of the MW value for achieving the image intensity is considered to be 2% of that of the fourth embodiment.
4) In Comparative Example 2 (MW value is 1), as compared with Example 4 (MW value is 2, residual rate is 70.8%), even if the MW value is decreased by 1, the abrasion test residual rate is 52.6. %, Which is extremely low. It is considered that this is mainly due to the decrease in the affinity between the resin and the pigment due to the decrease in the hydrophobicity of the pigment surface.
5) It is also considered that as another factor, plasticization of the resin by the residual solvent occurs in parallel, which significantly reduces the scratch test strength. Therefore, the lower the residual solvent concentration in the pigment, the better, and less than 500 ppm. It is preferably 300 ppm or less, more preferably 100 ppm or less, and most preferably 50 ppm or less.
6) In Comparative Example 1 (without finishing treatment of the present invention), the MW value was as high as 12%, and the residual rate of the rubbing test was 69.6% even though there was no residual high boiling point solvent. Lower than 1 and so on. The cause of this is presumed to be that large lump particles are present and the pigment is exposed on the printing surface as seen in the photograph of FIG. From this, when the MW value exceeds 10%, coarse particles are generated, and when the MW value is 2% or less, the surface of the pigment becomes hydrophilic and the adhesiveness to the resin decreases, resulting in a low rubbing test residual rate. Understood to do.
7) Even in a mixed system of different pigments (PY180) as in Example 5, the same effect as above is recognized, and it is also effective for improving the hue of the colorant.
8) The effect similar to the above is recognized even in the addition system of the fluorescent dye (SY160: 1) as in Example 6, and it is also effective for improving the saturation and brightness of the colorant.

Claims (18)

  Pigment Yellow 155 whose powder has a methanol wettability (MW value) of 2% or more and 10% or less.   The pigment yellow 155 according to claim 1, which has a primary particle diameter of 50 nm to 300 nm and an aspect ratio of 1 to 10 according to a TEM method.   Pigment Yellow 155 according to claim 1 or 2, wherein the residual content of the organic solvent is less than 500 ppm.   Pigment Yellow 155 according to claim 3, wherein the residual content of the organic solvent is less than 100 ppm.   Pigment Yellow 155 according to claim 3 or 4, wherein the organic solvent is an alcohol solvent having a boiling point of 95 ° C or higher.   The pigment yellow 155 according to claim 5, wherein the alcohol solvent is a linear, branched or cyclic C3 or more saturated or unsaturated monohydric or polyhydric alcohol solvent.   The alcohol solvent is selected from the group consisting of 1-propanol, 1-butanol, 2-butanol, isobutanol, 1-pentanol, 2-pentanol, 2-hexanol, 1-heptanol, 2-heptanol, ethylene glycol and glycerin. The pigment yellow 155 according to claim 6, which is one or more solvents selected.   Pigment Yellow 155 according to claim 6 or 7, wherein the alcohol solvent is the finishing solvent used in the manufacturing process.   An azo pigment composition comprising, in addition to Pigment Yellow 155 according to any one of claims 1 to 8, another coloring pigment and / or a yellow fluorescent dye.   Other coloring pigments are C.I. I. Pigment Yellow 74, C.I. I. Pigment Yellow 120, C.I. I. Pigment Yellow 151, C.I. I. Pigment Yellow 180, C.I. I. Pigment Yellow 185, C.I. I. Pigment Yellow 194, C.I. I. Pigment Yellow 198, C.I. I. Pigment Yellow 213, C.I. I. Pigment Yellow 214, and C.I. I. Pigment Yellow 217, which is one or more pigments selected from the group consisting of Solvent Yellow 33, Solvent Yellow 98, Solvent Yellow 131, Solvent Yellow 135, and Solvent Yellow 160: 1. The pigment composition according to claim 9, which is one or more dyes selected from the group.   A colorant composition containing at least Pigment Yellow 155 according to any one of claims 1 to 8, a polymer, and a wax.   A colorant composition comprising at least the pigment composition according to claim 9 or 10, a polymer and a wax. 1) Azo pigment synthesis process by coupling reaction of diazonium compound in aqueous solution,
2) Finishing treatment step of an azo pigment with an alcohol solvent having a boiling point of 95 ° C. or higher,
The method for producing Pigment Yellow 155 according to claim 1, further comprising: 1) Azo pigment synthesis process by coupling reaction of diazonium compound in aqueous solution,
2) Finishing treatment step of an azo pigment with an alcohol solvent having a boiling point of 95 ° C. or higher,
Including,
The method for producing a pigment composition according to claim 9 or 10, wherein another pigment and / or a fluorescent dye is added before or after finishing.   The alcohol solvent having a boiling point of 95 ° C. or higher is one or more selected from the group consisting of linear, branched or cyclic, saturated or unsaturated monovalent or polyvalent alcohols having 3 to 8 carbon atoms. 15. The method according to claim 13 or 14, which is the solvent of   The finishing treatment step is carried out by bringing the synthesized azo pigment and the alcohol solvent into contact with each other for 10 minutes or more at a temperature 0 to 100 ° C. higher than the boiling point of the alcohol solvent. The method described.   Use of Pigment Yellow 155 according to any one of claims 1 to 8 as a colorant or for imaging applications.   Use of the azo pigment composition according to claim 9 or 10 as a colorant or for imaging applications.