JP5633792B2 - Pigment dispersion and colorant - Google Patents

Description

  The present invention relates to a highly finely dispersed pigment composition, a pigment dispersion obtained by using the pigment composition, and a use thereof. More specifically, a pigment dispersion in which the pigment is highly finely dispersed, an acrylic resin-treated pigment composition (hereinafter sometimes referred to as “pigment composition”) used to give the pigment dispersion, a method for producing the same, And the colorant application of the pigment composition or the pigment dispersion.

  For colorants used in image recording materials and image display displays, especially those where the dispersion medium is an organic solvent, the pigment powder is finely dispersed in the dispersion medium using a pigment dispersant or pigment derivative. A pigment dispersion liquid is used. The pigment particles finely dispersed in the pigment dispersion in this case are very fine particles having an average particle diameter of 10 to 100 nm or less. When obtaining such a fine pigment dispersion, sufficiently refined pigments are used. When the fine pigment is dispersed using an organic solvent as a dispersion medium, a dry powder is used as the fine pigment, and the fine pigment powder is subjected to much time and energy in a disperser. To obtain a finely dispersed pigment dispersion.

  As a method for refining the pigment in the above, there is a method for refining the pigment by salt milling to reduce the particle diameter (for example, see Patent Documents 1 and 2). Salt milling involves mixing and kneading pigments, water-soluble organic solvents, and water-soluble inorganic salts with a kneader, etc., putting the kneaded material into a large amount of water, stirring at high speed, washing with filtered water, and drying and grinding. To obtain a fine pigment. However, the pigment finely divided by these methods may agglomerate into large particles due to the filtration pressure and drying in the step after miniaturization. On the other hand, as described above, particularly as a colorant for an image recording material or an image display, an extremely finely dispersed pigment dispersion is required. Therefore, for these applications, it is necessary to finely disperse the agglomerated pigment in the post-refining process until it becomes an extremely fine particle state. It took a lot of time and energy.

  On the other hand, for the purpose of preventing aggregation of the pigment, the surface treatment of the pigment before aggregation is performed by the following method. For example, there is a method in which a pigment before aggregation is treated with a low molecular compound such as rosin, a surfactant, or a pigment derivative. In addition, coating of pigment particles with resin (resin treatment) is also performed. In particular, when the acrylic resin is used as a pigment treating agent and the pigment particles are coated with the acrylic resin, the aggregation of the pigment particles is prevented and the coated acrylic resin is dispersed in the pigment dispersion step. It can be dissolved in a medium to act as a binder.

  Examples of a method for treating a pigment with an acrylic resin include the following methods. A method of surface-treating pigment by precipitating acrylic resin by phase transition or pH conversion in liquid, or adding acrylic resin or its solution to make pigment finer and kneading together to make finer pigment And pigment particles are coated at the same time, and then the kneaded product is precipitated in a poor solvent that does not dissolve the acrylic resin. By treating the pigment by these methods, the refined pigment is prevented from aggregating thereafter, so that it can be used as it is without being finely dispersed again as in the prior art. By dispersing this, a fine pigment dispersion can be provided.

  Here, the acrylic resin useful for finely dispersing the pigment is required to have a specific structure. Living radical polymerization, which is a precise synthesis method, is suitable for the production of such an acrylic resin. In this living radical polymerization, the growth terminal is stabilized to prevent coupling and disproportionation, which are side reactions of radical polymerization, to control the molecular weight of the resulting resin, narrow the molecular weight distribution, A higher order structure such as a copolymer can be obtained.

  Specific examples of the living radical polymerization method include the following various methods. For example, nitroxide method using dissociation and bonding of amine oxide radical (Nitroxide mediated polymerization, abbreviated as NMP method) (see Non-Patent Document 1), heavy metals such as copper, ruthenium, nickel, iron, etc., and forming complexes with them Atom transfer radical polymerization (abbreviated as ATRP method) in which a halogen compound is polymerized using a ligand as a starting compound using a ligand (see Patent Document 3 and Patent Document 4, Non-Patent Document 2), dithiocarboxylic acid ester, Reversible addition-fragmentation transfer (hereinafter abbreviated as RAFT method) in which a xanthate compound or the like is used as an initiating compound to polymerize using an addition polymerizable monomer and a radical initiator (see Patent Document 5), Macromolecular Design via Interchange of Xanthate (abbreviated as MADIX method) (see Patent Document 6) A method using heavy metals such as Lulu, organic bismuth, organic antimony, antimony halide, organic germanium, and germanium halide (Degenerative transfer, abbreviated as DT method) (see Patent Document 7 and Non-Patent Document 3) has been developed and widely used. Research and development is in progress.

JP-A-8-179111 Japanese Patent Laid-Open No. 2003-227921 Special Table 2000-500516 JP 2000-514479 A Special Table 2000-515181 International Publication No. 1999/05099 Pamphlet JP 2007-277533 A

Chemical Review (2001) 101, p3661 Chemical Review (2001) 101, p3689 Journal of American Chemical Society (2002) 124 p2874, (2002) 124 p13666, (2003) 125p8720

  In order to prevent pigment aggregation as described above, various methods have been taken. However, when using a low molecular weight compound such as rosin, the low molecular weight compound is not a foreign substance to the article to be colored. Thus, the performance of the article may be reduced. For example, the low molecular weight compound bleeds out on the surface of the article, or the surface is blistered to impair the appearance of the article, or deteriorate the resistance of the article such as water resistance, heat resistance and solvent resistance.

  On the other hand, when an acrylic resin is used to prevent aggregation of the pigment, there is no problem as described above, but there is a problem that the acrylic resin adhering to the pigment surface is fused when dried. In the case of fusing, since the fused acrylic resin must be dissolved when the treated pigment is used, it may take time to dissolve the resin when dispersing the pigment in the liquid medium.

  In addition, there is a method of using a resin having a low molecular weight in order to lower the viscosity of the pigment dispersion or to increase the solubility of the resin that is treating the pigment. However, even if the acrylic resin has a low molecular weight, it has a wide molecular weight distribution (weight average molecular weight / number average molecular weight) such as 1.7 to 3 because it includes a wide range of high molecular weight to low molecular weight molecular chains. It is. According to the study by the present inventors, it has been found that such dispersions in which pigments treated with acrylic resins having a wide molecular weight distribution have the following problems. Since the acrylic resin dissolved in the dispersion has a wide molecular weight distribution, problems such as an increase in the viscosity of the dispersion and variations in the viscosity and storage stability of the dispersion occur.

  Further, a resin having a wide molecular weight distribution includes a high molecular weight component having a high molecular weight polymer chain even if its number average molecular weight is small. Since this high molecular weight component is difficult to dissolve, it may take time to dissolve the resin in the liquid medium, and even if the pigment can be stably dispersed at the beginning, the dispersion of the pigment becomes unstable over time. Cause problems. Furthermore, in a resin having a broad molecular weight distribution, the amount of low molecular weight components increases, and the acrylic resin of the low molecular weight component deteriorates the physical properties of the resin film, is weak against heat, or has poor film strength. Doing so may cause the durability to deteriorate.

  Further, particularly when a pigment is used for a color filter resist as an image display, if the molecular weight distribution of the acrylic resin as a dispersion resin is wide, the alkali developability of the formed resist film varies depending on the molecular weight of the resin. Therefore, the following problems occur. That is, the development speed varies, such as a low development speed in the case of a high molecular weight component and a high speed in the case of a low molecular weight component. For this reason, development residues may remain on the color filter, productivity of the color filter may be reduced, and sharp edges of the color filter pixels after alkali development may be difficult to obtain.

  On the other hand, as a method for narrowing the molecular weight distribution of the acrylic resin, there is the living radical polymerization described above. However, each of the various living radical polymerization methods listed above has the following problems. For example, in the NMP method described above, a high temperature of 100 ° C. or higher is necessary, and in order to increase the polymerization rate, it is necessary to polymerize the monomer alone without using a solvent, and the polymerization conditions are severe. In addition, the methacrylate monomer generally does not proceed with the NMP method. In order to solve these problems, a special nitroxide compound is required. However, it is complicated and difficult to synthesize the special nitroxide compound. Further, in order to enable dispersion in an aqueous medium using an acrylic polymer, it is desirable to use an acrylic monomer having a carboxyl group, but by random polymerization of the monomer with another monomer, In addition, it is difficult to obtain a product with a controlled molecular weight.

  Further, in the above-described ATRP method, it is necessary to use heavy metal, and after polymerization, it is necessary to remove and purify the heavy metal from the polymer even if it is a trace amount. And when purifying the said polymer, since the heavy metal with a heavy load to an environment is contained also in the waste water and waste solvent which arise in a refinement | purification process, it is necessary to remove and purify | clean heavy metal also from them. In the ATRP method using copper, it is necessary to remove oxygen as the polymerization atmosphere. In this case, there is a method in which a reducing agent is added to make it difficult to be affected by oxygen. However, there is a possibility that the polymerization may be stopped in the middle, and it is essential to sufficiently remove oxygen. Furthermore, in the method of polymerizing by forming a metal complex using an amine compound as a ligand, the formation of the complex is inhibited if there is an acidic substance, so that it is difficult to polymerize using a monomer having an acid group. In order to introduce an acid group, the acid group must be blocked and polymerized, the block must be eliminated, and the acid group cannot be easily introduced into the polymer. That is, it is not easy to obtain a polymer introduced with a carboxyl group that satisfies the above-mentioned requirements by any of the above-described methods.

  Furthermore, in the above-described RAFT method and MATIX method, it is necessary to synthesize a special compound such as a dithiocarboxylic acid ester or a xanthate compound as a starting compound. Moreover, in this case, by using a sulfur compound, a sulfur-based unpleasant odor remains in the polymer, and there is also a coloration of the polymer, which needs to be removed. In addition, in the case of a monomer having an amino group, the dithiocarboxylic acid ester or xanthate compound of the starting compound is decomposed and polymerization does not proceed.

  Since the above-mentioned DT method uses heavy metals similarly to the ATRP method, it is necessary to remove the heavy metals used after the polymerization. When heavy metals are removed, there is a problem of purification of waste water generated at that time. Furthermore, it may be complicated and costly to synthesize a metal catalyst or organometallic starting compound used for polymerization as required.

  As described above, in any method, the reaction conditions are limited, a special compound is required, and the cost is high. Moreover, a random polymer could not be easily obtained with a monomer having a carboxyl group and another monomer.

In view of the above, the present inventors have provided an acrylic resin more useful for preventing pigment aggregation in order to achieve better fine dispersion of the pigment, and further coated with the acrylic resin. It was concluded that the development of a pigment composition was indispensable.
Accordingly, an object of the present invention is to provide an acrylic resin-treated pigment composition capable of achieving better pigment fine dispersion, and further a pigment dispersion using the same and various colorants.

Ie, the invention ing include organic pigment coated with an acrylic resin, the content of the organic pigment is dispersed Ru 5-95% by mass of acrylic resin-treated pigment composition in an organic solvent And 10 to 100% by weight of a pigment dispersant with respect to the organic pigment ,
The acrylic resin is
1) 90% by mass or more of the monomer constituting the acrylic resin is a (meth) acrylate monomer (a), and 20% by mass or more of the (meth) acrylate monomer (a) is an aromatic ring or alicyclic. A (meth) acrylate monomer having an alkyl group,
2) The number average molecular weight in terms of polystyrene in the gel permeation chromatograph is 2,000 to 20,000, and the dispersity (weight average molecular weight / number average molecular weight) indicating the distribution of molecular weight is 1.4 or less. ,And,
3) To provide a pigment dispersion characterized by having a glass transition temperature of 50 ° C. or higher.

In the present invention, the following forms are more preferable. The pigment dispersant is at least one selected from the group consisting of a surfactant, an acrylic dispersant, an ester dispersant, and a urethane dispersant; the acrylic resin is an AB block copolymer, At least one polymer block contains 30% by mass or more of a (meth) acrylate monomer having an aromatic ring or alicyclic alkyl group; an acrylic resin further having a carboxyl group-containing (meth) acrylate monomer as a copolymerization component wherein, that the acid value of 30~250mgKOH / g; acrylic resin, a a-B block copolymer, the acid value of the a blocks constituting the a-B block copolymer is 50 to 250 mg / g, And it is preferable that the acid value of B block is 0-50 mgKOH / g.

  Further, the acrylic resin used in the present invention is preferably the following. That is, the acrylic resin polymerizes a monomer using a radical generator using an organic iodide as a polymerization initiating compound and an organic compound having phosphorus, nitrogen, oxygen or carbon atoms that extracts iodine from the organic iodide as a catalyst. It is preferable that it is the acrylic resin obtained.

  In the above, the catalyst is phosphorus halide containing iodine atom, phosphite compound, phosphinate compound, imide compound, hydantoin compound, phenol compound, iodooxyphenyl compound, vitamins, cyclohexadiene , Preferably at least one selected from the group consisting of diphenylmethane and benzene iodide.

Further, the present invention provides a coloring agent characterized in that it comprises Pigments dispersions of the present invention.

  The pigment composition or pigment dispersion of the present invention prevents aggregation at the time of filtration or drying, and can be easily dispersed to the level of fineness in the dispersion process. Useful as a colorant for display displays.

  In view of the above-described problems of the prior art, the inventors of the present invention have achieved that an acrylic resin used for preventing pigment aggregation has a molecular weight distribution within a specific range in order to achieve better pigment fine dispersion. It came to the conclusion that it is effective to make things. And the said subject in the synthesis | combination of the structure of the refined pigment composition and its dispersion liquid required for that, and also the acrylic resin used for it was solved. In other words, the development of an acrylic resin that prevents aggregation of finer pigments, is easier to disperse, and can disperse the pigment in a fine particle form, and can be easily finely dispersed by coating the pigment with the acrylic resin. It was found that a product was obtained.

  The present inventors have found that a pigment dispersion obtained by dispersing this pigment composition gives an advanced fine dispersion state and high-performance color characteristics. Furthermore, it has been found that the pigment composition and the pigment dispersion give good performance when used as a colorant for an image forming material or an image display. Further, the present inventors have found a new living radical polymerization method that can make the obtained acrylic resin narrow in molecular weight distribution. According to this method, it is possible to obtain an acrylic resin or a block copolymer having a narrow molecular weight distribution, which is useful for achieving the object of the present invention, without the various problems of the conventional living radical polymerization described above. it can.

It is a figure which shows the GPC chart of the polymer of the synthesis examples 8-10 and the comparative synthesis examples 2 and 3. FIG.

Next, the present invention will be described in more detail with reference to preferred embodiments.
The pigment composition of the present invention comprises an organic pigment treated with an acrylic resin, the pigment content is 5 to 95% by mass, and the acrylic resin is
1) 90% by mass or more of the monomer constituting the resin is a (meth) acrylate monomer (a), and 20% by mass or more of the monomer (a) has an aromatic ring or an alicyclic alkyl group (meta) ) Acrylate monomer,
2) The number average molecular weight in terms of polystyrene in the gel permeation chromatograph is 2,000 to 20,000, and the dispersity (weight average molecular weight / number average molecular weight) indicating the distribution of molecular weight is 1.4 or less. ,And,
3) The glass transition temperature is 50 ° C. or higher.

The acrylic resin is an AB block copolymer, and it is more preferable that at least one polymer block contains 30% by mass or more of a (meth) acrylate monomer having an aromatic ring or an alicyclic alkyl group, The acrylic resin further contains a (meth) acrylate monomer having a carboxyl group as a copolymerization component, and the acid value of the resin is preferably 30 to 250 mgKOH / g. The acrylic resin is an AB block. It is a copolymer, The acid value of A block in a block copolymer is 50-250 mgKOH / g, It is preferable that the acid value of B block is 0-50 mgKOH / g. The A block and B block as used in the field of this invention mean the polymer block which comprises an AB block copolymer, respectively.

  The following can be used as a pigment used for this invention. The organic pigment used in the present invention is not particularly limited, and a soluble azo pigment, an insoluble azo pigment, a phthalocyanine pigment, a quinacridone pigment, an isoindolinone pigment, an isoindoline pigment, a perylene pigment, a perinone pigment, a dioxazine pigment, an anthraquinone pigment, a diester Anthraquinonyl pigment, anthrapyrimidine pigment, ansanthrone pigment, indanthrone pigment, flavanthrone pigment, pyranthrone pigment, diketopyrrolopyrrole pigment and the like. In addition to this, a pigment composed only of carbon atoms such as carbon black can be used as the pigment composed of carbon atoms.

  Preferred pigments in the present invention are the three primary colors Y (yellow), M (magenta), and C (cyan), which are useful as colorants for image forming materials, as well as orange and green colors. Yes, its main pigments and complementary colors. For example, as a typical example, as C color, PB15: 3, 15: 4, etc. As Y color, PY-74, PY-180, PY-185, PY-138, etc., as M color Are PR-122, PV-19, PR-269, etc., green colors are PG-7, PG-36, PG-58, etc., and orange colors are PO-61, etc. Not.

Further, in the present invention, since it is preferably used as a colorant for an image forming display, it is an R (red) color, a G (green) color, or a B (blue) color that is a primary color of light, and its main pigment and complementary color. Pigments.
Examples of the primary color R include PR-56, 58, 122, 166, 168, 176, 177, 178, 224, 242, 254, and the like; examples of the primary color G include PG-7, 36, 58, and the like. Y used as a complementary color is PY-12, 13, 14, 17, 24, 55, 60, 74, 83, 90, 93, 126, 128, 138, 139, 150, 154, 155, 180, 185 The main color B includes PB-15: 1, 15: 3, 15: 6, 60, 80, and the like; and the complementary color violet includes PV-19, 23, and the like. In the present invention, one or more of these are used, and these pigments are used alone, as a mixture, or as a mixed crystal.

  In addition, conventionally known pigment derivatives (synergists) may be used in combination with the above-mentioned pigments in the same manner as conventionally known methods. Examples of synergists include sulfonated and aminated compounds of pigment skeletons such as azo-based and phthalocyanine-based pigments. It is done. The usage-amount is 0.5-50 mass% with respect to a pigment, More preferably, it is 3-30 mass%. In particular, in the present invention, when an acrylic resin having an amino group is used, it is very preferable to use a sulfonated product of the same pigment as the pigment derivative (synergist). This is because the acidic group (sulfone group) on the pigment surface and the amino group of the acrylic resin are ionically bonded, and the pigment adsorption by the pigment dispersant due to the ionic bond is very effective for pigment dispersion.

  Next, the acrylic resin used in the present invention will be described. In this acrylic resin, (1) 90% by mass or more of the monomer constituting the resin is a (meth) acrylate monomer, and (2) (meth) acrylate having an aromatic ring or an alicyclic alkyl group among the monomers. Dispersity (weight average molecular weight / number average) having a monomer content of 20% by mass or more, (3) a polystyrene-reduced number average molecular weight in a gel permeation chromatograph of 2,000 to 20,000, and a molecular weight distribution. (Molecular weight) is 1.4 or less, and (4) the glass transition temperature is 50 ° C. or more.

  As a monomer which comprises the acrylic resin used by this invention, the 90 mass% or more needs that it is a (meth) acrylate type monomer. Any conventionally known monomer can be used as the monomer. For example, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, butyl (meth) acrylate, 2-methylpropane (meth) acrylate, t-butyl (meth) acrylate, pentyl (Meth) acrylate, hexyl (meth) acrylate, octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, nonyl (meth) acrylate, decyl (meth) acrylate, isodecyl (meth) acrylate, lauryl (meth) acrylate, tetradecyl (Meth) acrylate, octadecyl (meth) acrylate, behenyl (meth) acrylate, isostearyl (meth) acrylate, cyclohexyl (meth) acrylate, t-butylcyclohex (Meth) acrylate, t-butylcyclohexylmethyl (meth) acrylate, isobornyl (meth) acrylate, trimethylcyclohexyl (meth) acrylate, cyclodecyl (meth) acrylate, cyclodecylmethyl (meth) acrylate, tricyclodecyl (meth) acrylate , Tricyclohexyloxyethyl methacrylate, benzyl (meth) acrylate, phenyl (meth) acrylate, naphthyl (meth) acrylate, allyl (meth) acrylate, alkyl, alkenyl, cycloalkyl, aromatic ring (meth) acrylate, etc. Is mentioned.

  Moreover, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, cyclohexanedimethanol mono (meth) acrylate, cyclohexanediol mono Hydroxyl group-containing (meth) acrylates such as (meth) acrylate; mono (meth) acrylates of polyalkylene glycols such as polyethylene glycol mono (meth) acrylate and polypropylene glycol mono (meth) acrylate; (poly) ethylene glycol monomethyl ether (meth) Acrylate, (poly) ethylene glycol monolauryl ether (meth) acrylate, (poly) ethylene glycol monononyl phenyl ether (meth) acrylate Rate, (poly) propylene glycol - monomethyl ether (meth) acrylate, (poly) ethylene glycol (poly) propylene glycol monomethyl ether (meth) acrylate glycol ether, such as (meth) acrylate, and the like. In the above, “poly” and “(poly)” both mean n = 2 or more.

  Further, glycidyl group-containing (meth) acrylates such as glycidyl (meth) acrylate, 3,4-epoxycyclohexyl (meth) acrylate, (meth) acryloyloxyethyl glycidyl ether, (meth) acryloyloxyethoxyethyl glycidyl ether; Contains isocyanate groups such as (meth) acryloyloxyethyl isocyanate, 2- (2-isocyanatoethoxy) ethyl (meth) acrylate, and monomers of which isocyanate is blocked with ε-caprolactone, MEK oxime, pyrazole and the like ( (Meth) acrylates; cyclic (meth) acrylates such as tetrahydrofurfuryl (meth) acrylate and oxetanylmethyl (meth) acrylate; dimethylaminoethyl (meth) acrylate , Diethylaminoethyl (meth) acrylate, amino group-containing (meth) acrylates such as t- butylaminoethyl (meth) acrylate, and the like.

  In addition, halogen-containing (meth) acrylates such as octafluorooctyl (meth) acrylate and tetrafluoroethyl (meth) acrylate; 2- (4-benzoxy-3-hydroxyphenoxy) ethyl (meth) acrylate, 2- (2 ′ And (meth) acrylate that absorbs ultraviolet rays such as -hydroxy-5- (meth) acryloyloxyethylphenyl) -2H-benzotriazole. Since these monomers absorb ultraviolet rays, it is preferable to use them because they can contribute to increasing the light resistance of the pigment. Monomers such as silicon atom-containing (meth) acrylate having a trimethoxysilyl group or a dimethylsilicone chain can also be used.

  In the present invention, a macromonomer obtained by introducing a (meth) acryl group into one end of an oligomer obtained by polymerizing these monomers can also be used.

  Moreover, as a monomer component, the (meth) acrylate which has a group which can react with the functional group in the acrylic resin of this invention obtained using the (meth) acrylate monomer which has a functional group of a hydroxyl group or a carboxyl group For example, a photosensitive group may be introduced by reacting isocyanatoethyl (meth) acrylate, glycidyl (meth) acrylate, or the like.

  These (meth) acrylates occupy 90% by mass or more of the constituent components of the acrylic resin used in the present invention. For the remaining less than 10% by mass, a conventionally known radical polymerizable monomer is used and is not particularly limited. For example, styrene, vinyl toluene, maleic acid and its ester, vinyl acetate and the like can be mentioned.

  And especially in this invention, in the said (meth) acrylate monomer, it is required to use the acrylic resin which 20 mass% or more has an aromatic ring or an alicyclic (meth) acrylate as a structural component. Thus, in this invention, since the acrylic resin which uses the monomer which has an aromatic ring or alicyclic at high content is used for the acrylic resin which processes a pigment, the following advantage is acquired. That is, the glass transition point can be increased as the thermal property of the acrylic resin, the viscosity at the time of dissolving the solvent can be decreased, and the refractive index can be increased, which is useful in the present invention. On the contrary, the solvent solubility of the acrylic resin may deteriorate due to the aromatic ring or alicyclic group, but in the present invention, this property is used to encapsulate the pigment with the acrylic resin. Allows to be distributed. By encapsulating the pigment with an acrylic resin, the heat resistance of the pigment can be improved.

  Examples of the aromatic or alicyclic monomer that can be used in the present invention include the following. For example, as aromatic (meth) acrylate, phenyl (meth) acrylate, naphthyl (meth) acrylate, anthracenyl (meth) acrylate, benzyl (meth) acrylate, naphthylmethyl (meth) acrylate, tribromophenyl (meth) acrylate , (2- (4-Benzoxy-3-hydroxyphenoxy) ethyl (meth) acrylate, 2- (2′-hydroxy-5- (meth) acryloyloxyethylphenyl) -2H-benzotriazole, and the like. Cyclic (meth) acrylates include cyclohexyl (meth) acrylate, trimethylcyclohexyl (meth) acrylate, t-butylcyclohexyl (meth) acrylate, tricyclodecyl (meth) acrylate, and isobornyl (meth) acrylate. And the adamantyl (meth) acrylate, etc. The acrylic resin used in the present invention occupies 20% by mass or more of (meth) acrylate which is a component of 90% by mass or more. By introducing a monomer having an aromatic ring or alicyclic group, the glass transition point of the acrylic resin used in the present invention can be increased.

  Next, as the molecular weight of the acrylic resin used in the present invention, the number average molecular weight in terms of polystyrene in a gel permeation chromatograph (hereinafter abbreviated as GPC) is 2,000 to 20,000, and the dispersion shows the molecular weight distribution. The degree (weight average molecular weight / number average molecular weight, hereinafter sometimes referred to as PDI) is 1.4 or less. When the molecular weight is less than 2,000, the molecular weight is small, and thus the physical properties of the article may be lowered when used for coloring the article. On the other hand, when the molecular weight exceeds 20,000, the solubility in a solvent tends to deteriorate due to the large molecular weight, and the dispersibility of the pigment composition of the present invention may be lowered.

  The PDI of the acrylic resin used in the present invention is 1.4 or less, preferably 1.35 or less. This means that the molecular weight distribution of the acrylic resin is narrow, that is, the molecular weight is highly uniform. When the molecular weight is high, when viewed microscopically, it is considered that the solvent solubility is molecularly similar, the solvent solubility of the acrylic resin is improved, and the dispersion state is easily finely dispersed in the pigment. give. In addition, the narrow molecular weight distribution means that there are few things with large or small molecular weights, the properties of the resin are uniform, the deterioration of the solubility when the molecular weight is large, and the effect on the article when it is small. . As a result, the acrylic resin used in the present invention provides a highly finely dispersed state of the pigment. Further, since the molecular weight is uniform, the developability and development time of the color filter resist can be controlled, pixels with sharp edges can be formed, and the solvent solubility of the excess resist on the edge of the substrate is good. According to the study by the present inventors, the above effect cannot be obtained when the PDI of the acrylic resin exceeds 1.4.

  Next, the glass transition point (hereinafter abbreviated as Tg) of the acrylic resin used in the present invention is 50 ° C. or higher. This increases the Tg of the acrylic resin, thereby preventing the acrylic resin from being fused or melt-fixed when the pigment composition is dried. This is because if the Tg of the acrylic resin is lower than 50 ° C., the acrylic resin melts when the pigment composition is dried, and it may take time to dissolve the solvent of the acrylic resin when dispersing the pigment. In addition, when the pigment composition is stored at room temperature, it may be exposed to high temperatures in summer and the like, and the Tg of the acrylic resin is increased to prevent particles from blocking at high temperatures. Further, when the dispersion in the state where the pigment is encapsulated with an acrylic resin is to be obtained by utilizing the poor solvent solubility described above, when the Tg is lower than 50 ° C., the pigment composition is dried. At this temperature, the acrylic resin melts, and the melted acrylic resin is difficult to dissolve in the solvent, making it impossible to obtain a good pigment dispersion state.

The above Tg is an actual measurement value of a random polymer of an acrylic resin obtained by a conventionally known measurement such as thermal analysis. Alternatively, it may be a value that can be calculated by a conventionally known method. In this calculation method, the Tg of the acrylic resin composed of the monomer of the X component (X is 2 or more) can be calculated from the Tg of the homopolymer of each component monomer and the mass ratio of the monomer by the following formula.
1 / T = A / Ta + B / Tb + C / Tc ... + X / Tx
(T is Tg of the random polymer, absolute temperature, A, B, C... Are mass ratios in the X component, Ta, Tb, Tc... Are Tg of homopolymers of the respective monomers, and absolute temperature. .)

The use of an acrylic resin having the above monomer composition, molecular weight, and physical properties is a feature of the present invention. Preferably, the acrylic resin is an AB block copolymer, and at least one of the polymer blocks has a fragrance. An acrylic resin containing 30% by mass or more of a (meth) acrylate monomer having a ring or alicyclic alkyl group may be used.

This is because the (meth) acrylate monomer having an aromatic ring or alicyclic alkyl group as described above may be all introduced into one of the polymer blocks, or the ratio of (meth) acrylate between A and B is It may be different. A (meth) acrylate monomer having an aromatic ring or an alicyclic alkyl group may be introduced into the acrylic resin at a ratio of 20% by mass or more. More preferably, the ratio of the (meth) acrylate monomer having an aromatic ring or an alicyclic alkyl group may be biased. This to be able to change the solvent solubility of the resin, or encapsulated solvent insoluble pigment monomer having the aromatic ring or alicyclic alkyl group, the one of the polymer blocks exhibit solvent solubility Thus, a pigment composition (treated pigment) that can be dispersed more stably can be obtained. The ratio varies depending on the type of monomer and is arbitrary.

  The acrylic resin used in the present invention preferably contains (meth) acrylate having an acid group, particularly preferably a carboxyl group, as a copolymerization component, and the acid value of the resin is 30 to 250 mgKOH / g. preferable. This is useful for improving the alkali development when used as a color filter resist and the adhesion of the resist film to the substrate.

  Examples of the (meth) acrylate having a carboxyl group include (meth) acrylic acid, acrylic acid dimer, hydroxyalkyl (meth) acrylate ester of cyclohexanedicarboxylic anhydride, phthalic anhydride, maleic anhydride, succinic anhydride, tetrahydro An ester type monomer obtained by reacting a dibasic acid such as phthalic anhydride or cyclohexene dicarboxylic acid anhydride may be mentioned, and is not particularly limited. The acid value of the acrylic resin having an acid group is preferably 30 to 250 mgKOH / g. If the acid value is less than 30 mgKOH / g, sufficient alkali development of the resist cannot be obtained, while the acid value exceeds 250 mgKOH / g. And various physical properties such as water resistance of a film such as a resist formed may be inferior.

  The acrylic resin used in the present invention may be an AB random polymer having the above monomer composition, molecular weight, and physical properties, but is an AB block copolymer having the above monomer composition, molecular weight, and physical properties. It is preferable. Particularly preferably, the A block in the AB block copolymer has a carboxyl group, the acid value thereof is 50 to 250 mgKOH / g, the acid value of the B block is 0 to 50 mgKOH / g, the A block and the B block are Block copolymers having different acid values. Here, in the A-B block copolymer, A and B are different polymer blocks, and in order to distinguish one block unit from the other, A and B are used for explanation. Hereinafter, the AB block copolymer of the above-described embodiment suitable for the present invention will be described.

  In the above, the A block has a higher acid value than the B block, and this part functions to increase the solubility during alkali development. The acid value is 50 to 250 mg KOH / g, preferably 50 to 200 mg KOH / g. The B block has an acid value lower than that of the A block and may have an acid value of 0 having no acid group. When the acid value is 0, the solvent solubility is effective, and the compatibility of the article with other resins is improved. The B block is a polymer block that improves the pigment adsorptivity with the pigment dispersion or encapsulates the pigment. Further, when the acid value is 0, the B block does not have alkali solubility, and thus developability may be deteriorated. Accordingly, the B block preferably has an acid group having an acid value lower than that of the A block. The acid value of the B block is 0 to 50 mgKOH / g, preferably 5 to 30 mgKOH / g.

  In the present invention, the acrylic resin having the above configuration is used, and a method for obtaining the acrylic resin will be described. This acrylic resin can be easily obtained by the following novel living radical polymerization found by the present inventors. That is, organic iodide is used as a polymerization initiating compound, and iodine is extracted from the organic iodide. Phosphorus halides containing iodine atoms, phosphite compounds, phosphinate compounds and other organic phosphorus compounds, imide compounds, hydantoin compounds Polymerize monomers using radical generators using organic nitrogen compounds such as compounds, organic compounds such as phenolic compounds, iodooxyphenyl compounds, vitamins, and organic compounds such as cyclohexadiene, diphenylmethane, or benzene iodide. Thus obtained acrylic resin can be suitably used in the present invention.

  The above polymerization method is a novel living radical polymerization found by the present inventors, which is different from the conventional radical polymerization and living radical polymerization. Unlike conventional living radical polymerization methods, the living radical polymerization performed in the present invention does not use metal compounds or ligands, and does not require the use of special compounds such as nitroxides, dithiocarboxylic acid esters, and xanthates. In addition, radical polymerization using a conventionally known addition polymerizable monomer and a polymerization initiator that is a radical generator can be easily performed by using an initiator compound that is an organic iodide and a catalyst as described above in combination.

The above-mentioned living radical polymerization method is considered to proceed by a reaction mechanism represented by the following general reaction formula. That is, the polymerization proceeds by a reversible active reaction of the dormant species Polymer-X (PX) to the growth radical. This polymerization mechanism may vary depending on the type of catalyst, but is considered to proceed as follows. In Formula 1, P · generated from the polymerization initiator reacts with XA to generate catalyst A · in situ. A. acts as an activator of PX, and this catalysis activates PX at a high frequency.

  More specifically, the radical generated from the polymerization initiator in the presence of the initiator compound to which iodine (X) is bonded draws the active hydrogen or active halogen atom of the catalyst to become the catalyst radical A. Next, the A · pulls out X of the starting compound to become XA, and the starting compound becomes a radical, and the monomer is polymerized to the radical, and X is immediately pulled out from XA to prevent the termination reaction. Further, A. withdraws X from the terminal X by heat or the like, becomes XA and a terminal radical, the monomer reacts there, and immediately gives X to the terminal radical and stabilizes. By repeating this, polymerization proceeds and the molecular weight and structure can be controlled. However, in some cases, a bimolecular termination reaction or disproportionation may be involved as a side reaction.

  Each component used for the living radical polymerization will be described. The starting compound for starting the living radical polymerization is not particularly limited as long as it is a conventionally known organic iodide. Specific examples include methyl iodide, ethyl iodide, propyl iodide, isopropyl iodide, butyl iodide, t-butyl iodide; iodophenylmethane, iododiphenylmethane, iodotriphenylmethane, 2-iodo. Alkyl iodides such as -1-phenylethane, 1-iodo-1-phenylethane, 1-iodo-1,1-diphenylethane, diiodomethane; iododichloromethane, iodochloromethane, iodotrichloromethane, iododibromomethane Organic halides containing iodine atoms such as;

  1-iodoethanol, 1-iodopropanol, 2-iodopropanol, 2-iodo-2-propanol, 2-iodo-2-methylpropanol, 2-phenyl-1-iodoethanol, 2-phenyl-2 -Iodinated alcohols such as iodoethanol; ester compounds of these alcohols with carboxylic acid compounds such as acetic acid, butyric acid, fumaric acid; iodoacetic acid, α-iodopropionic acid, α-iodobutyric acid, α-iodoiso Butyric acid, α-iodovaleric acid, α-iodoisovaleric acid, α-iodocaproic acid, α-iodophenylacetic acid, α-iododiphenylacetic acid, α-iodo-α-phenylpropionic acid, α-iodo-β Phenylpropionic acid, β-iodopropionic acid, β-iodobutyric acid, β-iodoisobutyric acid β-iodovaleric acid, β-iodoisovaleric acid, β-iodocaproic acid, β-iodophenylacetic acid, β-iododiphenylacetic acid, β-iodo-α-phenylpropionic acid, β-iodo-βphenylpropion Iodinated carboxylic acids such as acids; esterified products of these iodinated carboxylic acids with methanol, ethanol, phenol, benzyl alcohol, and the above-described iodinated alcohols; acid anhydrides of these iodinated carboxylic acids; Acid anhydrides such as chloride and bromide of carboxylic acid; iodoacetonitrile, 2-cyano-2-iodopropane, 2-cyano-2-iodobutane, 1-cyano-1-iodocyclohexane, 2-cyano-2- And cyano group-containing iodides such as iodovaleronitrile.

  Moreover, although these compounds can use a commercial item as it is, they can be obtained by a conventionally well-known method. For example, it can be obtained by reacting an azo compound such as azobisisobutyronitrile with iodine. Alternatively, instead of iodine in the organic iodide described above, halogen exchange using an organic halide substituted with other halogen atoms such as bromide or chloride using an iodide salt such as quaternary ammonium iodide or sodium iodide. An organic iodide used in the present invention can be obtained by reaction. They are not particularly limited.

  In particular, the reaction between the azo compound and iodine does not require the synthesis of the starting compound in advance, and the polymerization proceeds by in-situ formation of the starting compound by adding iodine and the azo compound during polymerization. Very easy and preferred.

  As the catalyst used in the present invention, an organic phosphorus compound, an organic nitrogen compound, an organic oxygen compound, or an organic compound having active carbon, which becomes a radical by extracting an iodine atom of the above-described starting compound can be used. Preferably, phosphorus halides containing iodine atoms, phosphite compounds, organophosphorus compounds that are phosphinate compounds, imide compounds, organic nitrogen compounds that are hydantoin compounds, phenol compounds, and iodooxyphenyl A compound selected from at least one of organic compounds such as compounds, organic oxygen compounds that are vitamins, cyclohexadiene, diphenylmethane, and benzene iodide can be used.

  These compounds are not particularly limited, but specific examples thereof include phosphorus halides containing iodine atoms, phosphite compounds, and phosphinate compounds. Examples of such materials include dichloroiodolin, dibromoiodrine, phosphorus triiodide, dimethyl phosphite, diethyl phosphite, dibutyl phosphite, diperfluoroethyl phosphinate, diphenyl phosphite, dibenzyl phosphite. Bis (2-ethylhexyl) phosphite, bis (2,2,2-trifluoroethyl) phosphite, diallyl phosphite, ethylene phosphite, ethoxyphenyl phosphinate, phenylphenoxy phosphinate, ethoxymethyl phosphinate And phenoxymethyl phosphinate.

Nitrogen compounds include imide compounds and hydantoin compounds such as succinimide, 2,2-dimethylsuccinimide, α, α-dimethyl-β-methylsuccinimide, 3-ethyl-3-methyl-2,5-pyrrolidinedione, Cis-1,2,3,6-tetrahydrophthalimide, α-methyl-α-propylsuccinimide, 5-methylhexahydroisoindole-1,3-dione, 2-phenylsuccinimide, α-methyl-α-phenylsuccinimide, 2,3-diacetoxysuccinimide, maleimide, phthalimide, 4-methylphthalimide, N-chlorophthalimide, N-bromophthalimide , 4 -nitrophthalimide, 2,3-naphthalenecarboximide, pyromellitic diimide, 5-bromoisoindole- 1,3-Geo , N- chlorosuccinimide, N- bromosuccinimide, N- eye odometer succinimide, hydantoin, and the like Giay odo hydantoin.

  As the oxygen compound, there can be used a phenol compound which is a phenolic hydroxyl group having a hydroxyl group in an aromatic ring, an iodooxyphenyl compound which is an iodide of the phenolic hydroxyl group, and vitamins. For example, as phenols, phenol, hydroquinone, methoxyhydroquinone, t-butylphenol, t-butylmethylphenol, catechol, resorcinol, di-t-butylhydroxytoluene, dimethylphenol, trimethylphenol, di-t-butylmethoxyphenol, hydroxy Examples thereof include a polymer obtained by polymerizing styrene or a hydroxyphenyl group-supported polymer fine particle thereof. Since these are added as a polymerization inhibitor for storage of the monomer, the effect can be exhibited by using the commercially available monomer as it is without purification. Examples of the iodooxyphenyl compound include thymol diiodide, and examples of vitamins include vitamin C and vitamin E.

  Examples of the organic compound having active carbon include cyclohexadiene, diphenylmethane, and iodobenzene. The amount of these catalysts is less than the number of moles of the polymerization initiator. If the number of moles is too large, the polymerization is too controlled and the polymerization does not proceed.

  Next, as a polymerization initiator (sometimes referred to as a radical generator) used in the present invention, conventionally known ones can be used, and are not particularly limited, and usually used organic peroxides and azo compounds. Can be used. Specific examples include benzoyl peroxide, dicumyl peroxide, diisopropyl peroxide, di-t-butyl peroxide, t-butyl peroxybenzoate, t-hexyl peroxybenzoate, t-butyl peroxy-2-ethylhexanoate. , T-hexylperoxy-2-ethylhexanoate, 1,1-bis (t-butylperoxy) 3,3,5-trimethylcyclohexane, 2,5-dimethyl-2,5-bis (t-butyl) Peroxy) hexyl-3,3-isopropyl hydroperoxide, t-butyl hydroperoxide, dicumyl hydroperoxide, acetyl peroxide, bis (4-t-butylcyclohexyl) peroxydicarbonate, isobutyl peroxide, 3 , 3,5-Trimethylhexanoyl par Xoxide, lauryl peroxide, 1,1-bis (t-butylperoxy) 3,3,5-trimethylcyclohexane, 1,1-bis (t-hexylperoxy) 3,3,5-trimethylcyclohexane, 2, 2'-azobis (isobutyronitrile), 2,2'-azobis (2,4-dimethylvaleronitrile), dimethyl 2,2'-azobis (isobutyrate), 2,2'-azobis (methoxydimethylvaleronitrile) Etc.

  The polymerization initiator is used in an amount of 0.001 to 0.1 mol times, more preferably 0.002 to 0.05 mol times based on the number of moles of monomers. If the amount is too small, the yield is insufficient. If the amount is too large, there is a possibility that a polymer containing only the addition polymerization monomer may be formed.

  As mentioned above, the acrylic resin used by this invention can be obtained by superposing | polymerizing at least using the start compound which is an organic iodide, an addition polymerizable monomer, a polymerization initiator, and a catalyst. The polymerization may be bulk polymerization without using an organic solvent, but preferably solution polymerization using a solvent. Although the organic solvent used in this case is not particularly limited, the following can be used. For example, hydrocarbon solvents such as hexane, octane, decane, isodecane, cyclohexane, methylcyclohexane, toluene, xylene, ethylbenzene;

  Alcohol solvents such as methanol, ethanol, propanol, isopropanol, butanol, isobutanol, hexanol, benzyl alcohol, cyclohexanol; ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, methyl cellosolve, ethyl cellosolve, butyl cellosolve, propylene glycol monomethyl ether , Propylene glycol monoethyl ether, propylene glycol monopropyl ether, diglyme, triglyme, dipropylene glycol dimethyl ether, butyl carbitol, butyl triethylene glycol, methyl dipropylene glycol, methyl cellosolve acetate, propylene glycol monomethyl ether acetate, dipropylene glyco Butyl ether acetate, glycol solvents such as diethylene glycol monobutyl ether acetate;

Ether solvents such as diethyl ether, dipropyl ether, methylcyclopropyl ether, tetrahydrofuran, dioxane, anisole;
Ketone solvents such as methyl ethyl ketone, diethyl ketone, methyl isobutyl ketone, cyclohexanone, isophorone, acetophenone;
Ester solvents such as methyl acetate, ethyl acetate, butyl acetate, propyl acetate, methyl butyrate, ethyl butyrate, caprolactone, methyl lactate and ethyl lactate; halogenated solvents such as chloroform and dichloroethane;
Amide solvents such as dimethylformamide, dimethylacetamide, 2-pyrrolidone, N-methylpyrrolidone, caprolactam;
Examples thereof include dimethyl sulfoxide, sulfolane, tetramethyl urea, ethylene carbonate, propylene carbonate, dimethyl carbonate and the like. These may be used alone or as a mixed solvent of two or more. What is necessary is just a solvent which melt | dissolves the initiator which is the organic iodide used by this invention, a catalyst, an addition polymerizable monomer, and a polymerization initiator.

  The solid content (monomer concentration) of the polymerization liquid (reaction liquid) is not particularly limited, but is preferably 5 to 80% by mass, more preferably 20 to 60% by mass. When the solid content is less than 5% by mass, the monomer concentration may be too low and the polymerization may not be completed. On the other hand, in the polymerization of 80% by mass to bulk, the viscosity of the polymerization solution becomes too high to be stirred, The polymerization yield may be deteriorated.

  The polymerization temperature is not particularly limited, and is preferably 0 ° C to 150 ° C, more preferably 30 ° C to 120 ° C. The polymerization temperature is adjusted by the half-life of each polymerization initiator. The polymerization time is preferably continued until the monomer runs out, but is not particularly limited. For example, 0.5 to 48 hours, preferably 1 to 24 hours, more preferably 2 hours as a practical time. Time to 12 hours.

The polymerization atmosphere is not particularly limited, and polymerization may be performed as it is. That is, oxygen may be present in the system within a normal range, and may be performed under a nitrogen stream to remove oxygen, if necessary. Moreover, although the material used for superposition | polymerization may remove an impurity with distillation, activated carbon, or an alumina, a commercial item can be used as it is. Further, the polymerization may be performed under light shielding, and there is no problem even if it is performed in a transparent container such as glass.
As described above, it is possible to easily obtain an acrylic resin having a molecular weight distribution suitable for the present invention by polymerizing using an organic iodide as the starting compound and using at least an addition polymerizable monomer, a polymerization initiator and a catalyst. Can do.

  Next, the AB block copolymer suitable for the present invention can be easily produced by the above polymerization method, and the method will be described. First, a (meth) acrylate monomer constituting a block of the A chain is polymerized using a monofunctional organic iodide as a starting compound. Since the polymer terminal thus obtained is stabilized because it is substituted with an iodine group, the polymerization can be started again by adding the monomer again and dissociating it by heat or the like.

  The A-chain polymer block obtained as described above is taken out and purified, and dissolved again in an organic solvent. Using this as a starting compound, a (meth) acrylate monomer constituting the next B-chain polymer block is added. To do. Preferably, further, polymerization is performed by adding a catalyst and a polymerization initiator, whereby iodine at the end of the polymer is dissociated and polymerization is started again to obtain a block copolymer in which the B chain block is linked to the A chain block. Can do. Further, after forming the A-chain polymer block, without taking out the polymer, a monomer for constituting the B-chain block is added as it is, preferably by adding a catalyst and a polymerization initiator to perform polymerization. A block copolymer suitable for the present invention can also be obtained.

Further, even if the monomer of the A block is not completely polymerized, the acid value of the A block and the amount of the (meth) acrylate monomer having an aromatic ring or alicyclic alkyl group are set, and B The acid value of the block and the amount of the (meth) acrylate monomer having an aromatic ring or alicyclic alkyl group may be used, and the polymerization rate of the A block monomer is 50% by mass or more, more preferably 80% by mass or more. Thus, polymerization may be carried out by adding a B block monomer. The addition may be performed all at once or by dropping with a dropping device. By dripping, the B block copolymer can be a concentration gradient in the polymer of the monomer, that is, a gradient polymer.

  Similarly, the order of production of the polymer blocks is reversed. First, the monomers constituting the polymer block of the B chain are polymerized, and then the monomers constituting the polymer block of the A chain are polymerized. Block copolymers may be obtained.

  In the polymerization method used in the present invention, the molecular weight of the polymer can be controlled by the amount of the starting compound. That is, by setting the number of moles of the monomer with respect to the number of moles of the starting compound, the arbitrary molecular weight or the molecular weight can be controlled. For example, when 1 mol of the starting compound is used and 500 mol of the monomer having a molecular weight of 100 is used for polymerization, a theoretical molecular weight of 1 × 100 × 500 = 50,000 is given. That is, the set molecular weight can be calculated by the formula [1 mol of starting compound × monomer molecular weight × monomer to starting compound molar ratio].

  However, the polymerization method used in the present invention may involve a bimolecular termination or a disproportionation side reaction, and may not achieve the above theoretical molecular weight. Polymers without these side reactions are preferred, but they can be coupled to increase molecular weight or stopped to decrease molecular weight. Further, the polymerization rate may not be 100%, the remaining monomer is distilled off, removed when the acrylic resin is precipitated, or after obtaining a desired acrylic resin, a polymerization initiator or a catalyst is added. The polymerization may be completed. The acrylic resin used in the present invention may be produced and contained, and in the case of a block copolymer, there is no problem even if each block copolymer unit is included.

  When the acrylic resin used in the present invention is an acrylic resin having an acid group, it may be used as it is without being neutralized, or may be used as an aqueous solution after neutralizing the acid group. The alkali for neutralizing the acid group is not particularly limited, and ammonia; amines such as diethanolamine, triethylamine, diethanolamine, triisopropanolamine; terminal amines of polyalkylene glycol; lithium hydroxide, sodium hydroxide, potassium hydroxide, Examples thereof include alkali metal salts such as sodium carbonate, calcium hydroxide and zinc hydroxide, and alkaline earth metal salts.

  The acrylic resin used in the present invention may be used as it is as an acrylic resin solution after polymerization, or in the case of an acrylic resin having a carboxyl group, it may be used as an aqueous solution obtained by ionizing a carboxyl group with an alkaline aqueous solution. Then, the obtained polymerization solution may be dried to obtain a resin solid, or the resin solution may be added to a poor solvent to cause precipitation, and the resin solid may be taken out. The neutralized product may be neutralized with an acidic substance and acidified to take out the resin solid. The acidic substance used for this neutralization is conventionally known and is not particularly limited. For example, inorganic acids such as hydrochloric acid, sulfuric acid and nitric acid, and organic acids such as acetic acid, propionic acid and toluenesulfonic acid are used. The acid may be added as it is, but is preferably used in an aqueous solution of 10% by mass or less. In addition, an acid aqueous solution may be added to the alkali neutralized aqueous solution of the acrylic resin, and conversely, an acrylic resin aqueous solution may be added to the acid aqueous solution.

  Moreover, although an iodine atom is used in the present invention, it may be used in a state in which the iodine is bound, but it is preferable that the iodine is detached from the molecule so that the iodine can be removed. The method is a conventionally known method and is not particularly limited, but may be desorbed by heating, desorbed by adding an acid or alkali, or decomposed by adding sodium thiosulfate or the like. . In the present invention, the iodine atom is removed in the washing step because it takes a washing step in the pigment treatment.

  As described above, the acrylic resin used in the present invention can be easily obtained. Next, the pigment composition of the present invention obtained by coating a pigment with the above acrylic resin and a method for producing a pigment dispersion using the same will be described.

  The pigment composition of the present invention is a pigment composition that is treated with an acrylic resin containing 5 to 95% by mass of an organic pigment. When the pigment exceeds 95% by mass, that is, when the acrylic resin is less than 5% by mass, the acrylic resin is insufficient to prevent aggregation of the pigment. In addition, when the pigment composition of the present invention is used for an article to be colored, the pigment concentration is less than 5% by mass, that is, the acrylic resin is 95% by mass or more. Then, since the acrylic resin provided to the article to be colored is contained in a large amount, there is a possibility that the influence of the acrylic resin is greatly exerted on the article to be colored. Preferably, the amount of organic pigment is 30 to 95% by weight, more preferably 50 to 90% by weight. The amount of acrylic resin used for the pigment is adjusted in advance by these amounts.

The pigment composition of the present invention treated with the above acrylic resin can be obtained, for example, by the following method.
(1) A method of adding an acrylic resin or a solution thereof at the time of pigment synthesis or particle size adjustment.
(2) A method of mixing and kneading a pigment and an acrylic resin or a solution thereof with a stirrer or a kneader.
(3) A method of stirring and dispersing a pigment and an alkali neutralized aqueous solution of an acrylic resin having a carboxyl group, and then neutralizing with an acid to precipitate the acrylic resin.

  First, the method (1) will be described. In this method (1), a pigment can be obtained by synthesis by a conventionally known method, but an acrylic resin or an acrylic resin can be obtained at the time of synthesis or after synthesis, at the time of aging or sizing, and at the time of crystal adjustment. This is a method of treating a pigment by adding a solution. In particular, the method of pigment synthesis, ripening, sizing, and crystal adjustment is not limited. It is used for each pigment synthesis, ripening, granulating, and crystal adjustment.

  Examples of the synthesis include synthesis of a pigment by adding an acrylic resin or an acrylic resin solution at the time of blending raw materials when synthesizing a conventional pigment. In the example after the synthesis, an acrylic resin or a resin solution is added after the pigment synthesis to obtain a mixture of the pigment and the resin. For example, in the case of an aqueous pigment such as an azo-based pigment, a pigment is synthesized by adding an acrylic resin having a carboxyl group and neutralizing the carboxyl group or having a polyalkylene glycol chain. Or an acrylic resin can be added after the pigment synthesis. When the pigment is synthesized in a solvent such as copper phthalocyanine, the acrylic resin or the acrylic resin solution is added as it is to synthesize the pigment, or after the synthesis, the pigment can be treated. Also, in the case of pigment sizing, ripening, and crystal growth, for example, when heating or adding an aromatic hydrocarbon solvent emulsion to grow crystals, an acrylic resin is added to the pigment and A mixture of resins can be obtained.

  These are still just a mixture of pigment and resin, and these are filtered, washed, dried as they are, or when the acrylic resin is insoluble in water, an organic solvent that does not dissolve the acrylic resin, preferably Is preferably added to a solvent having a low solubility of the acrylic resin, such as water, methanol, hexane, or a mixed solution thereof, to precipitate the acrylic resin and deposit and coat the acrylic resin on the pigment particles. In addition, when using a neutralized acrylic resin as the acrylic resin, the kneaded product is added to the acid aqueous solution, and the acrylic resin is neutralized and deposited on the pigment particles. A pigment composition can be obtained. These pigment compositions are preferably filtered and washed thoroughly. This washing may be water or a mixture of a water-soluble organic solvent and water. Thus, the pigment composition of the present invention can be obtained by the method (1).

  Next, the method (2) will be described. Method (2) is a method in which a pigment and an acrylic resin or a solution thereof are mixed and kneaded with a stirrer or a kneader to obtain a pigment composition. This method is a method in which the refining of the pigment and the coating of the pigment with an acrylic resin are simultaneously performed. In this method, at least a pigment and an acrylic resin are kneaded by a conventional method. The acrylic resin to be used may be added in advance so as to have a desired pigment content at the time of kneading or stirring, or a part of the acrylic resin may be added and added after kneading so as to have a desired pigment content. Alternatively, after kneading, an acrylic resin may be added and further kneaded. Although it does not specifically limit as a kneading | mixing method, For example, it is 30 minutes-60 hours by heating at normal temperature with a conventionally well-known kneader, such as a kneader, an extruder, a ball mill, 2 rolls, 3 rolls, Preferably 1 Knead for 12 hours.

  In addition, carbonate and chloride salts are used in combination as fine media to make the pigment finer in the mixture as necessary, and viscosity such as ethylene glycol and diethylene glycol is used to impart lubricity. It is preferable to use an organic solvent in combination. In order to make the pigment surface acidic or basic in advance, a synergist may be added. The salt is used in an amount of 1 to 30 times by mass, preferably 2 to 20 times by mass with respect to the pigment. The amount of the viscous organic solvent used is adjusted according to the viscosity at the time of pigment kneading. In the above method, the acrylic resin may be a resin solid, a resin solution after polymerization, or an aqueous acrylic resin solution neutralized with alkali after polymerization. Next, the kneaded material is deposited as described above, and the pigment is coated with an acrylic resin. Thus, the pigment composition of the present invention can be obtained by the method (2).

  Next, the method (3) will be described. Method (3) is a method in which a pigment and an alkali neutralized aqueous solution of an acrylic resin having a carboxyl group are stirred and dispersed, neutralized with an acid to precipitate an acrylic resin, and the pigment is coated with the resin. In this method, an aqueous acrylic resin solution is used, the pigment is stirred in an aqueous solution, preferably dispersed to obtain an aqueous pigment dispersion, and then neutralized with an acidic substance to precipitate the acrylic resin. The pigment is coated with a resin with a finely dispersed particle size.

  The pigment is dispersed by a conventionally known method using a pigment, an acrylic resin neutralized with an alkali, water, and, if necessary, an aqueous organic solvent. The pigment to be used may be a powder, but is a finely divided pigment, and more preferably a water paste of the finely divided pigment. The pigment concentration of the dispersion is 0.5 to 70% by mass, preferably 5 to 50% by mass in the dispersion, although the amount of the acrylic resin used depends on the type of pigment and the intended use. 5 to 500 parts by mass per 100 parts by mass is desirable. That is, the coated pigment coated with an acrylic resin preferably contains 20 to 95% by mass of the pigment.

  The method for dispersing the pigment is a conventionally known method and is not particularly limited. The pigment, the acrylic resin neutralized with alkali, water, and an organic solvent are mixed and stirred, and the pigment is dispersed by a conventionally known disperser. As a disperser, for example, a kneader, an attritor, a ball mill, a sand mill using glass or zircon, a horizontal media mill disperser, a colloid mill, or the like can be used. In a bead mill, a bead medium of 1 μm or less is used as the medium. preferable.

  The obtained aqueous pigment dispersion may be used as it is, but coarse particles that are slightly present may be removed by a centrifuge, an ultracentrifuge, or a filter. The aqueous pigment dispersion obtained in this dispersion step is used as a pre-aqueous pigment dispersion.

  Next, the pre-aqueous pigment dispersion obtained above is diluted as it is or with water to a pigment content of 10% by mass or less, and an acrylic resin neutralized to a desired pigment content is added as necessary. To do. Next, since the acid group of the acrylic resin is neutralized with an alkali, ionized and dissolved in water, the acrylic resin can be insolubilized in water by adding an acid thereto. By doing so, acrylic resin can be deposited on the pigment particles, that is, encapsulated (coated). While the pre-aqueous pigment dispersion is diluted with water and stirred by a conventionally known method, the acid is gradually added using a stirrer such as a dissolver that can be stirred at high speed. The addition amount of the acid is at least equimolar with the alkali neutralizing the acrylic resin, more preferably at least 1.1 times the molar.

  After the acrylic resin is precipitated by addition of an acid, the precipitate is filtered. After the precipitation, the particles may be heated as necessary to aggregate the precipitated particles and facilitate filtration. It is preferable to sufficiently remove ionic substances and organic solvents adhering to the precipitate by this filtration. Thus, the pigment composition of the present invention can be obtained by the method (3).

  Since the pigment composition obtained by these methods is to be dispersed in an organic solvent, it is essential to dry it. As described above, the pigment which has not been treated with resin is hardly aggregated by drying, and it takes a lot of time and energy to finely disperse the pigment. However, the pigment composition treated with the acrylic resin that characterizes the present invention prevents the aggregation of the pigment due to filtration and drying, and the dispersion of the acrylic resin in the liquid medium easily or easily dissolves when dispersed. A finely dispersed pigment dispersion is obtained.

  The above-mentioned drying is a conventionally known drying, and the temperature is a temperature at which moisture evaporates, and is not particularly limited. It is particularly preferable that the drying is performed at a Tg or less of the acrylic resin used in the present invention because it prevents the resin from being fused or melted. The drying method is a conventionally known method, and blow drying, spray drying, reduced pressure drying, freeze drying, or the like is used. Particularly preferred are vacuum drying and freeze drying. This is because the above-described melting or fusion occurs when drying is performed at a Tg or higher of the acrylic resin, so that the method can be dried at a low temperature.

  The pigment composition obtained by drying may be used as it is, but is preferably pulverized. The pulverization method and the particle size after pulverization are not particularly limited, and any conventionally known method and arbitrary pulverized particle size can be used.

  By the above production methods (1) to (3), a pigment composition coated with an acrylic resin can be obtained. Next, a pigment dispersion finely dispersed in a liquid medium that is an organic solvent using the pigment composition of the present invention will be described.

  The liquid medium used for the pigment dispersion of the present invention is the above-described organic solvent and is not particularly limited. As the organic solvent, vinyl monomers such as (meth) acrylate and styrene which are the polymerizable monomers described above can be used as the liquid dispersion medium. One or more of them may be used.

  The pigment dispersion of the present invention is obtained by dispersing the above-described pigment composition of the present invention in an organic solvent. Since the acrylic resin used in the present invention is dissolved in an organic solvent and has a function as a binder, it is preferable to use a pigment dispersant as needed in order to disperse the pigment more stably. As the pigment dispersant, conventionally known dispersants listed below are used and are not particularly limited. For example, one or more surfactants, acrylic dispersants, ester dispersants, urethane dispersants, and the like are used. A structure having a linear, random copolymer, graft copolymer, comb copolymer, block copolymer, star polymer, dendrimer, or the like is used. In addition, as the adsorbing part to the pigment of the dispersant, a basic functional group such as an amino group is used when the pigment surface is acidic, and a sulfonic acid, phosphoric acid, carboxyl group, etc. when the pigment surface is basic. In addition, a dispersant using adsorption by hydrogen bonding with the pigment surface or adsorption by π-π stacking is also used. The amount of these dispersants added to the pigment is 5 to 200% by mass, preferably 10 to 100% by mass.

  Upon dispersion, according to the use of the pigment dispersion, various resins that are binder components such as acrylic resin, polyester, urethane resin, epoxy resin, leveling agent, photopolymerization initiator, ultraviolet absorber, light stabilizer, matte You may use additives, such as an agent, a crosslinking agent, antioxidant, and also a synergist and other pigment dispersants.

  Further, the pigment concentration of the pigment dispersion of the present invention is appropriately adjusted depending on the application. For example, the pigment is 5 to 30% by mass, preferably 10 to 25% by mass.

  The pigment dispersion of the present invention is prepared by mixing an organic solvent, the pigment composition of the present invention described above, a pigment dispersant, and, if necessary, an additive and a resin, adjusting the pigment concentration to an arbitrary level, and mixing the mixture as described above. It can be obtained by stirring and dispersing. The obtained pigment dispersion may be used as it is, but it is preferable to remove coarse particles which are slightly present with a centrifuge, an ultracentrifuge or a filter in order to improve the reliability of the dispersion.

  The viscosity (25 ° C.) of the pigment dispersion of the present invention is 1 to 50 mPa · s, preferably 2 to 30 mPa · s. Since the acrylic resin used in the present invention has a narrow PDI and does not contain a high molecular weight component, one of the major features of the present invention is that the viscosity of the pigment dispersion can be lowered. As described above, a pigment dispersion can be obtained using the pigment composition of the present invention.

  The pigment composition and pigment dispersion of the present invention can be suitably used for, for example, a colorant for an image recording material or a colorant for an image display. For pigment dispersions used in colorants for these applications, there is a demand for pigment dispersions that are very finely dispersed and have a low viscosity. Examples of the image recording material in the present invention include oil-based inkjet ink, UV curable inkjet ink, and toner. Oil-based and UV inkjet inks require low-viscosity pigment dispersions, but the acrylic resin used in the present invention has a narrow PDI and a small amount of high-molecular weight components, which makes it very useful to reduce the viscosity of inks. Achieve.

  In addition, as a toner used as a colorant, there is a chemical toner, and one of them is a polymerized toner obtained by suspending in a monomer such as styrene. In this case, toner particles in which the pigment is finely dispersed can be obtained by mixing the pigment composition of the present invention or a pigment dispersion thereof with the monomer. There is also a method in which a pigment composition or a dispersion of a pigment dispersion and a toner binder dissolved in an organic solvent is suspended to form particles, and the organic solvent is distilled off from the particles to obtain particles to obtain toner. However, even in this case, a good toner in which the pigment is finely dispersed can be obtained.

Moreover, a color filter is mentioned as an image display display which is one of the use of a coloring agent. The pixel formation method of the color filter is not particularly limited, and the color filter is used for application by a spin coater or a slit or an ink jet method. By using the pigment composition or pigment dispersion of the present invention, a finely dispersed colorant for a color filter can be obtained, and a color filter with high contrast and high brightness can be obtained. In addition, since the molecular weight distribution of the acrylic resin used in the present invention is uniform, the color resist has good alkali developability in the production of a color filter, and the development speed is also the molecular weight of the acrylic resin and the monomer composition. Can be controlled with. The ink-jet method of the color filter printing method is very preferable because the viscosity can be lowered as described above.
The blending, materials, methods and the like of the colorant described above are conventionally known and are not particularly limited, and the pigment concentration can be used in accordance with each color concentration.

Next, although a synthesis example, an Example , a reference example, and a comparative example are given and this invention is demonstrated further more concretely, this invention is not limited at all by these examples. In the text, “part” or “%” is based on mass.

[Synthesis Example 1]: Synthesis of random copolymer having no acid value-1
In a reaction vessel equipped with a stirrer, a reverse flow condenser, a thermometer and a nitrogen introduction tube, 106 parts of propylene glycol monomethyl ether acetate (hereinafter abbreviated as PGMAc), 2.3 parts of iodine, 2,2′-azobis (isobutyro) Nitrile) (hereinafter abbreviated as AIBN) 4.5 parts, methyl methacrylate (hereinafter abbreviated as MMA) 75 parts, benzyl methacrylate (hereinafter abbreviated as BzMA) 31 parts, and 3,5-di-tert-butylhydroxytoluene (Hereinafter abbreviated as BHT) 0.30 part was charged and polymerized at 80 ° C. for 5 hours while bubbling nitrogen to obtain a polymer solution. This is designated as A-01. This solid content was measured, and the polymerization conversion rate converted from the nonvolatile content was 100%. In the differential refractive index detector (hereinafter abbreviated as RI) in GPC, Mn was 5,500 and PDI was 1.20. When Tg was measured by thermal analysis, it was about 84 ° C.

[Synthesis Example 2]: Synthesis of random copolymer having no acid value-2
In the same reaction vessel as in Synthesis Example 1, 100 parts of xylene, 1.45 parts of iodine, 2.8 parts of AIBN, 80 parts of BzMA, 20 parts of cyclohexyl methacrylate (hereinafter abbreviated as CHMA), and 0. 30 parts were charged and polymerized at 80 ° C. for 5 hours while bubbling nitrogen to obtain a polymer solution. This is designated as A-02. This solid content was measured, and the polymerization conversion rate converted from the nonvolatile content was 100%. Moreover, Mn in RI by GPC was 8,500, and PDI was 1.24. Tg was 54 ° C.

[Synthesis Example 3]: Synthesis of random copolymer having no acid value-3
In a reaction vessel similar to Synthesis Example 1, 100 parts of PGMAc, 3.0 parts of iodine, 5.9 parts of AIBN, 80 parts of BzMA, 20 parts of 2-hydroxyethyl methacrylate (hereinafter abbreviated as HEMA) and N- 0.03 part of iodosuccinimide (hereinafter abbreviated as NIS) was charged and polymerized at 80 ° C. for 5 hours while bubbling nitrogen to obtain a polymer solution.

Subsequently, the nitrogen cylinder was changed to an air cylinder, and air was bubbled. In the system, 0.5 part of hydroquinone (hereinafter abbreviated as HQ), 9.5 parts of methacryloyloxyethyl isocyanate (trade name Karenz MOI, manufactured by Showa Denko KK, hereinafter abbreviated as MOI), and 9.5 parts of PGMac 0.02 part of the mixture and diazabicycloundecene were added, and the hydroxyl group of HEMA and the isocyanate group of MOI were reacted to introduce a methacryl group as an unsaturated bond into the side chain (hereinafter referred to as MOI. The reaction product is expressed as “HEMA + MOI”). The reaction was measured with an infrared spectrophotometer (hereinafter abbreviated as IR), and the reaction was continued until the peak of about 2100 cm ⁻¹ of the isocyanate disappeared.
This is designated as A-03. This solid content was measured, and the polymerization conversion rate converted from the nonvolatile content was 100%. Moreover, Mn in RI by GPC was 4,100, and PDI was 1.19. Tg was 51.2 ° C.

[Synthesis Example 4]: Synthesis of block copolymer having no acid value-1
In the same reaction vessel as in Synthesis Example 1, 134.4 parts diethylene glycol dimethyl ether (hereinafter abbreviated as DMDG), 1.9 parts iodine, 2,2′-azobis (4-methoxy-2,4-dimethylvaleronitrile) (Hereinafter abbreviated as V-70), 6.7 parts, 52.8 parts of BzMA, and 0.03 parts of NIS were charged, and polymerized at 50 ° C. for 4 hours while bubbling nitrogen, to be a first stage polymer. Got. Sampling and measuring the solid content, the polymerization conversion rate converted from the non-volatile content was 95%. At this time, Mn in RI was 3,700, and PDI was 1.21.

  Next, 73 parts of MMA was added, and further polymerized at the same temperature for 3 hours to obtain a block copolymer solution. This is designated as B-01. This solid content was measured, and the polymerization conversion rate converted from the nonvolatile content was 100%. At this time, Mn of RI of GPC was 8,500, and PDI was 1.25. Since the molecular weight is extended from the A block, it is considered that a block copolymer was obtained. About Tg, the endothermic peak was not clear and was unclear. However, in the homopolymers of the respective polymer blocks, the Tg of MMA is 105 ° C. and the Tg of BzMA is 54 ° C. Therefore, the Tg of the block copolymer is considered to be 50 ° C. or more.

[Synthesis Example 5]: Synthesis of block copolymer having no acid value-2
In a reaction vessel similar to Synthesis Example 1, 150 parts of methyl ethyl ketone (hereinafter abbreviated as MEK), 1.5 parts of iodine, and 2,2′-azobis (2,4-dimethylvaleronitrile) (hereinafter abbreviated as V-65). ), 40 parts of BzMA, 9 parts of isobutyl methacrylate (hereinafter abbreviated as iBMA), and 0.03 part of NIS, and polymerized at 75 ° C. for 5 hours with nitrogen bubbling to obtain a polymer solution. It was. Sampling and measuring the solid content, the polymerization conversion rate converted from the non-volatile content was 95%. At this time, Mn in RI was 4,100, and PDI was 1.21.

  Subsequently, 10 parts of N, N-dimethylaminoethyl methacrylate (hereinafter abbreviated as DMAEMA) and 10 parts of MMA were added and further polymerized at the same temperature for 4 hours to obtain a block copolymer solution. This is designated as B-02. This solid content was measured, and the polymerization conversion rate converted from the nonvolatile content was 100%. At this time, Mn of RI of GPC was 4,500, and PDI was 1.25. The molecular weight does not increase so much, but this is thought to be because the basicity was adsorbed on the column and could not be measured well. As confirmation, when 10% acetic acid was added to the resin solution and further diluted with water, it turned white and cloudy, but there was no precipitation. It is considered that this polymer was emulsified by forming a salt with acetic acid and the salt having solubility in water. That is, it is considered that a block copolymer having an amino group was obtained. About Tg, the endothermic peak was not clear and was unclear. However, the calculated value of the polymer Tg of each polymer block is 53 ° C. for BzMA / iBMA and 54 ° C. for DMAEMA / MMA, so that the Tg of the block copolymer is considered to be 50 ° C. or more.

[Synthesis Example 6]: Block copolymer-3 without acid value
In a reaction vessel similar to Synthesis Example 1, 94 parts of tetrahydrofuran (hereinafter THF), 1.01 part of iodine, 4.9 parts of V-70, 2- (2′-hydroxy-5-methacryloyloxyethylphenyl) ) -2H-benzotriazole (trade name RUVA-93, manufactured by Otsuka Chemical Co., Ltd., hereinafter abbreviated as RUVA) 32.3 parts and BHT 0.22 parts were charged and polymerized at 40 ° C. for 8 hours with nitrogen bubbling. Thus, a polymer solution was obtained. Mn in RI by GPC was 2,000, PDI was 1.27, and there was almost no peak derived from RUVA of the monomer. Further, when the resin THF solution at this stage was added to isopropanol (hereinafter abbreviated as IPA), it became cloudy. That is, this RUVA homopolymer is considered insoluble in IPA.

  Next, a mixed solution of 35.2 parts of BzMA and 20 parts of MMA was added, and further polymerized at 40 ° C. for 3 hours to obtain a polymer solution. This is designated as B-03. Moreover, Mn in RI by GPC was 5,600, and PDI was 1.26. Tg was unclear. However, Tg is considered to be 50 ° C. or higher for the same reason as in Synthesis Example 4. Subsequently, 100 ml of ethanol solution in which 0.5 g of potassium hydroxide was dissolved was added to decompose terminal iodine.

  Next, the polymer solution obtained as described above was charged into 2 liters of water while stirring at high speed. As a result, a slightly yellowish resin solid was obtained, filtered and dried to obtain a resin powder. This powder was added to ethyl acetate to a solid content of 5%, added to IPA, and stirred with a magnetic stirrer to give a translucent dispersion. This is because the RUVA polymer part constituting the polymer obtained as described above is insoluble in IPA as described above, but the MMA / BzMA part of the polymer block is dissolved in ethyl acetate, so that the dispersion liquid Is considered to have been obtained.

[Synthesis Example 7]: Synthesis of Random Copolymer with Acid Value-1
In a reaction vessel similar to Synthesis Example 1, 150 parts of PGMAc, 1.0 part of iodine, 3.6 parts of V-70, 85 parts of BzMA, 15 parts of acrylic acid (hereinafter abbreviated as AA), and NIS Was polymerized at 40 ° C. for 8 hours with nitrogen bubbling to obtain a polymer solution. This is C-01. This solid content was measured, and the polymerization conversion rate converted from the nonvolatile content was 98%. Moreover, Mn in RI by GPC was 11,800, and PDI was 1.31. The acid value was 116 mgKOH / g, and Tg was 59 ° C.

[Synthesis Example 8]: Synthesis of Random Copolymer with Acid Value-2
In a reaction vessel similar to Synthesis Example 1, 150 parts of DMDG, 1.2 parts of iodine, 5.5 parts of V-70, 55 parts of BzMA, 25 parts of methacrylic acid (hereinafter abbreviated as MAA), CHMA 20 parts and BHT 0.30 part were charged and polymerized at 40 ° C. for 8 hours while bubbling nitrogen to obtain a polymer solution. This is designated as C-02. This solid content was measured, and the polymerization conversion rate converted from the nonvolatile content was 99%. Moreover, Mn in RI by GPC was 7,500, and PDI was 1.29. The weight average molecular weight is 9,700. The measured value of Tg was 87.6 ° C. The acid value was 163 mgKOH / g.
Next, after cooling to 50 ° C., a mixture of 20 parts of a 25% aqueous ammonia solution and 130 parts of ion-exchanged water was prepared in a separate container and added to the polymerization system. The carboxyl group was ionized and dissolved in water to prepare an aqueous solution type.

[Synthesis Example 9] Synthesis of random copolymer having acid value-3
The same procedure as in Synthesis Example 8 was performed except that the amounts of iodine and V-70 in Synthesis Example 8 were changed to 1.9 parts and 8.0 parts in the same reaction vessel as in Synthesis Example 1, respectively. This is C-03. This solid content was measured, and the polymerization conversion rate converted from the nonvolatile content was 99%. Moreover, Mn in RI by GPC was 5,100, and PDI was 1.25. Tg and acid value were almost the same as in Synthesis Example 8. Similarly, it was neutralized with ammonia to form an aqueous solution.

[Synthesis Example 10]: Synthesis of Random Copolymer with Acid Value-4
The same procedure as in Synthesis Example 8 was performed except that the amounts of iodine and V-70 in Synthesis Example 8 were changed to 3.0 parts and 12.0 parts, respectively, in the same reaction vessel as in Synthesis Example 1. This is C-04. This solid content was measured, and the polymerization conversion rate converted from the nonvolatile content was 100%. Moreover, Mn in RI by GPC was 3,500, and PDI was 1.21. Tg and acid value were almost the same as in Synthesis Example 8. Similarly, it was neutralized with ammonia to obtain an aqueous solution.

[Synthesis Example 11]: Synthesis of Random Copolymer with Acid Value-5
In a reaction vessel similar to Synthesis Example 1, 150 parts of PGMAc, 1.0 part of iodine, 4.0 parts of V-70, 55 parts of BzMA, 25 parts of MAA, 3,3,5-trimethylcyclohexyl methacrylate ( (Hereinafter abbreviated as TMCHMA) 20 parts and 0.30 part of BHT were charged and polymerized at 50 ° C. for 8 hours while bubbling nitrogen to obtain a polymer solution. This solid content was measured, and the polymerization conversion rate converted from the nonvolatile content was 100%. Moreover, Mn in RI by GPC was 8,500, and PDI was 1.27.

Subsequently, the nitrogen cylinder was changed to an air cylinder, and air was bubbled. 0.5 part of HQ, 24.7 parts of glycidyl methacrylate (hereinafter abbreviated as GMA), 37.2 parts of PGMAc, and 1.18 parts of triethylammonium bromide were added to the system. The carboxylic acid of MAA and the epoxy group of GMA were reacted at 80 ° C. for 3 hours to introduce a methacryl group as an unsaturated bond into the side chain (hereinafter referred to as “MAA + GMA” when this MAA was reacted with GMA). To do). The reaction was traced until a predetermined acid value was reached, and further, it was confirmed by IR whether hydroxyl groups were formed and epoxy groups (about 940 cm ⁻¹ ) had disappeared. This is C-05. This solid content was measured, and the polymerization conversion rate converted from the nonvolatile content was 100%. Moreover, Mn in RI by GPC was 9,100, and PDI was 1.37. Tg was 61.2 ° C. The acid value was 52.1 mgKOH / g.

[Synthesis Example 12]: Synthesis of block copolymer-1
In a reaction vessel similar to Synthesis Example 1, 150 parts of DMDG, 1.5 parts of iodine, 5.4 parts of V-70, 50 parts of CHMA, 20 parts of MAA, and 0.05 part of NIS were charged. Then, polymerization was carried out at 50 ° C. for 5 hours with nitrogen bubbling to obtain a first stage polymer. Sampling and measuring the solid content, the polymerization conversion rate converted from the non-volatile content was almost 100%. At this time, Mn in RI was 5,900, and PDI was 1.23. The acid value was 186 mgKOH / g.

  Next, 30 parts of MMA was added and polymerized at the same temperature for 3 hours to obtain a block copolymer solution. This is designated as D-01. This solid content was measured, and the polymerization conversion rate converted from the nonvolatile content was 99%. At this time, Mn in RI of GPC was 7,900, and PDI was 1.25. The molecular weight extends from the A block and is considered a block copolymer. The acid value was 130 mgKOH / g.

[Synthesis Example 13] Synthesis of block copolymer-2
In a reaction vessel similar to Synthesis Example 1, 150 parts of DMDG, 1.0 part of iodine, 3.6 parts of V-70, 40 parts of MMA, 20 parts of MAA, and 0.05 part of NIS were charged. Polymerization was performed at 50 ° C. for 5 hours with nitrogen bubbling to obtain a first stage polymer. Sampling and measuring the solid content, the polymerization conversion rate converted from the non-volatile content was almost 100%. At this time, Mn in RI was 7,000, and PDI was 1.28. The acid value was 209 mgKOH / g.

  Next, 40 parts of CHMA was added, and further polymerized at the same temperature for 3 hours to obtain a block copolymer solution. This is designated as D-02. This solid content was measured, and the polymerization conversion rate converted from the nonvolatile content was 99%. At this time, Mn of RI of GPC was 12,100, and PDI was 1.33. It is thought that the block copolymer was obtained because the molecular weight was extended from the A block. The overall acid value was 129 mg KOH / g.

[Synthesis Example 14]: Synthesis of block copolymer-3
In a reaction vessel similar to Synthesis Example 1, 150 parts of DMDG, 1.5 parts of iodine, 5.3 parts of V-70, 50 parts of BzMA, 19 parts of MAA, and 0.05 part of NIS were charged. Then, polymerization was carried out at 50 ° C. for 5 hours with nitrogen bubbling to obtain a first stage polymer. Sampling and measuring solid content, the polymerization conversion rate converted from the non volatile matter was 96%. At this time, Mn in RI was 7,400, and PDI was 1.23. The acid value was 179 mgKOH / g.

  Next, 20 parts of MMA and 1 part of MAA were added, and further polymerized at the same temperature for 3 hours to obtain a block copolymer solution. This is designated as D-03. This solid content was measured, and the polymerization conversion rate converted from the nonvolatile content was 100%. At this time, Mn in RI of GPC was 8,200, and PDI was 1.23. The total acid value was 144.9 mgKOH / g.

[Comparative Synthesis Example 1]
In a reaction vessel similar to that of Synthesis Example 1, 150 parts of xylene was taken and heated to 80 ° C. while being purged with nitrogen. Next, a solution prepared by dissolving 3.5 parts of AIBN in a monomer mixture consisting of 80 parts of BzMA and 20 parts of CHMA is dropped into the reaction vessel from the dropping funnel over 2 hours, and further polymerized at 80 ° C. for 6 hours. To obtain a polymer solution. This is designated as R-01. Mn in RI by GPC was 8,700, and PDI was 2.02. Tg was 83.2 ° C.
This is a polymer obtained by the normal radical polymerization of Synthesis Example 2 described above.

[Comparative Synthesis Example 2]
In a reaction vessel similar to Synthesis Example 1, 150 parts of DMDG was taken and heated to 90 ° C. while being purged with nitrogen. Next, 3.0 parts of tert-butylperoxy-2-ethylhexanoate and 3.0 parts of 1-dodecanethiol were dissolved in a monomer mixture consisting of 55 parts of BzMA, 25 parts of MAA and 20 parts of CHMA. The solution was dropped into the reaction vessel from the dropping funnel over 2 hours, and further polymerized at 90 ° C. for 6 hours to obtain a polymer solution. The polymerization rate was almost 100%. This is designated as R-02. Mn in RI by GPC was 6,500, Mw was 12,400, and PDI was 1.9. Moreover, the acid value was 161 mgKOH / g and Tg was 82.9 degreeC. This was neutralized with ammonia in the same manner as in Synthesis Example 8 to make an aqueous solution.

[Comparative Synthesis Example 3]
The same procedure was performed except that 3.0 parts of tert-butylperoxy-2-ethylhexanoate and 3.0 parts of 1-dodecanethiol in Comparative Synthesis Example 2 were replaced with 1.5 parts and 1.5 parts, respectively. . The polymerization rate was almost 100%. This is designated as R-03. Mn in RI by GPC was 9,100, and PDI was 1.84. Moreover, the acid value was 163 mgKOH / g and Tg was 83.9 degreeC. In the same manner as in Comparative Synthesis Example 2, the solution was neutralized with ammonia to form an aqueous solution.

  Comparative Synthesis Examples 2 and 3 are the polymers of Synthesis Examples 8 to 10 and obtained by ordinary polymerization, and the molecular weight was adjusted using a chain transfer agent. The GPC chart is shown in FIG.

  This is a GPC outflow chart, where the horizontal axis represents molecular weight, the left is high molecular weight, and the right is low molecular weight. The vertical axis shows the RI absorption. As can be seen from this figure, in the polymerization method of the present invention, it can be confirmed that the molecular weight peak is sharp and the molecular weight distribution is narrow. It can also be seen that the molecular weight can be controlled by the amount of the starting compound. However, it can be seen that ordinary radical polymerization has a broad molecular weight distribution.

  Further, in Synthesis Example 8 and Comparative Synthesis Example 3 having the same peak top molecular weight, although the peak top molecular weight is the same, the number average molecular weight that is easily affected by low molecular weight is 7,500 in Synthesis Example 8. The comparative synthesis example 3 is 6,500, and it can be seen that the comparative synthesis example has more low molecular weight. Further, the weight average molecular weight that is easily affected by the high molecular weight is 9,700 in Synthesis Example 8, and 12,400 in Comparative Synthesis Example 3, and it can be seen that Comparative Synthesis Example 3 has a high molecular weight. Further, the molecular weight at the rising edge of measurement in Comparative Synthesis Example 3 is 60,000, whereas the molecular weight at the rising edge in Synthesis Example 8 is 30,000, and the acrylic resin having a narrow molecular weight distribution does not have a large molecular weight. I understood it.

[Comparative Synthesis Example 4]
In a reaction vessel equipped with a stirrer, a back-flow condenser, a thermometer and a nitrogen introduction tube, 100 parts of PGMAc, 2.3 parts of iodine, 4.5 parts of AIBN, 75 parts of MMA, n-butyl methacrylate (hereinafter referred to as nBMA) 25 parts of (abbreviation) and 0.30 part of BHT were charged and polymerized at 80 ° C. for 5 hours while bubbling nitrogen to obtain a polymer solution. This is designated as R-04. This solid content was measured, and the polymerization conversion rate converted from the nonvolatile content was 100%. Moreover, Mn in RI by GPC was 5,500, and PDI was 1.20. This is obtained by the living radical polymerization method used in the present invention and has a Tg of 60 ° C., but does not contain aromatic or alicyclic compounds.
Table 1 shows the composition, molecular weight, acid value, and Tg of each polymer in these synthesis examples. Comparative synthesis examples are summarized in Table 2.

  In Table 1, the monomer / monomer represents a random polymer chain, -b- represents a block copolymer on both sides, the monomer-monomer represents a reaction product between the monomers, and the acid value of the block is the total acid value. And () represent the acid value of each polymer block unit.

[ Reference Example 1]
100 parts of dimethylquinacridone pigment (PR-122), which is a magenta pigment, 200 parts of diethylene glycol (hereinafter abbreviated as DEG), 40 parts of A-01 (solid content 50%) obtained in Synthesis Example 1 and 800 parts of salt The mixture was put into a 3 L kneader, adjusted to keep the temperature at 100 to 120 ° C., and ground for 4 hours to obtain a kneaded product. When observed with a microscope, the average particle size of the pigment was 97 nm.

  This was put into 2,000 parts of water, heated to 80 ° C., and stirred at high speed for 4 hours. Subsequently, filtration and washing were performed to obtain a pigment paste (solid content 30%). It is considered that the resin precipitates and coats the pigment when it is poured into this water. Next, 240 parts of this pigment paste was added to 1,000 parts of water, re-peptized, and then filtered and washed. Subsequently, it was dried for 24 hours in a 50 ° C. vacuum dryer. It became a brittle and fine block pigment. Subsequently, it was pulverized by an attritor type pulverizer to obtain a powder pigment. This is designated as resin-treated magenta pigment-1.

  Further, a resin-treated pigment was obtained in the same manner except that A-02 obtained in Synthesis Example 2 was used instead of the resin A-01 used above. According to TEM observation, the average particle diameter of the pigment is 100 nm, which is referred to as resin-treated magenta pigment-2.

[Comparative Example 1]
It was used in Reference Example 1, except for using R-04 obtained in Comparative Synthesis Example 4 in place of the A-01 was in the same manner as in Reference Example 1 to obtain a resin-treated pigment. The average particle diameter of the obtained pigment is 98 nm, and this is referred to as comparative resin-treated magenta pigment-1.

[ Reference Example 2]
A resin-treated pigment was obtained using a copper phthalocyanine pigment (PB-15: 3), which is a cyan pigment, in the same manner as in Reference Example 1 except that the type of pigment was changed. The average particle size of the pigment after refinement was 89 nm. This pigment is referred to as resin-treated cyan pigment-1. Similarly, a resin-treated pigment was obtained using B-01 instead of A-01. This is referred to as resin-treated cyan pigment-2. The average particle size of the pigment was 92 nm.

[ Reference Example 3]
5 g of B-03 obtained in Synthesis Example 6 was dissolved in 50 g of xylene. Next, 500 parts of ion exchange water and 3.5 parts of polyethylene glycol lauryl ether (HLB15.4) were dissolved in a 2000 ml beaker. Next, while stirring the aqueous solution at a high speed, the xylene solution of B-03 was added to prepare a xylene emulsion.

  Further, 1,000 ml of ion-exchanged water and 77 g of a yellow azo pigment (PY-74, average particle diameter 75 nm, solid content 26%) were added to another container and stirred at high speed to peptize. The whole amount of the xylene emulsion was added to the peptized aqueous solution and aged at 70 ° C. for 2 hours with good stirring. Next, the solution was filtered while hot, washed well with a mixed aqueous solution of water / methanol 50/50 (w / w), then dried with a blow dryer at 70 ° C., dried and pulverized. This pigment is referred to as resin-treated yellow pigment-1. When observed with a microscope, the average particle size of the pigment was 106 nm.

  Further, a resin-treated pigment was obtained in the same manner as above except that A-02 obtained in Synthesis Example 2 was used instead of B-03 used above. This is referred to as resin-treated yellow pigment-2. The average particle size of the pigment was 99 nm.

[Comparative Example 2]
A resin-treated pigment was obtained in the same manner as in Reference Example 3 except that R-01 obtained in Comparative Synthesis Example 1 was used instead of B-03 used in Reference Example 3. This is referred to as comparative resin-treated yellow pigment-1. The average particle diameter of the pigment was 101 nm.

[ Reference Example 4]
100 parts of blue phthalocyanine blue pigment (PB-15: 6), 200 parts of diethylene glycol, 40 parts of A-03 (solid content 50%) obtained in Synthesis Example 3, and 800 parts of salt are 3 L of kneader. The mixture was adjusted to keep the temperature at 100 to 120 ° C. and ground for 8 hours to obtain a kneaded product.

  This was put into 2,000 parts of water, heated to 80 ° C. and stirred at high speed for 4 hours. Subsequently, filtration and washing were performed to obtain a wet cake of pigment (pure pigment content 30%). Drying at 80 ° C. for a whole day and night gave a blue pigment coated with a resin. As a result of TEM observation, the average particle diameter of the primary particle pigment was 30 nm. This is designated as resin-treated blue pigment-1.

  Further, instead of the copper phthalocyanine pigment (PB-15: 6), a red-colored diketopyrrolopyrrole pigment (PR-254) is used, and a resin-treated red pigment-01 (average particle size 43 nm) is used. Moreover, resin-treated green pigment-1 (average particle diameter 36 nm) was obtained using zinc phthalocyanine (PG-58), which is a green pigment.

[ Reference Example 5]
A blue pigment, a red pigment, and a green pigment were respectively treated in the same manner as in Reference Example 4 except that the resin A-03 used for the pigment treatment was replaced with C-05 obtained in Synthesis Example 11. The thus-obtained products were resin-treated blue pigment-2 (average particle size 36 nm), resin-treated red pigment-2 (average particle size 39 nm), and resin-treated green pigment-2 (average particle size 42 nm), respectively. It was.

[ Reference Example 6]
Instead of A-03 used in Reference Example 4, B-02 obtained in Synthesis Example 5 was used, and in the case of a blue pigment or a green pigment during kneading, monosulfonated copper phthalocyanine was used as the pigment. On the other hand, in the case of 5% red pigment, 10% monosulfonated diketopyrrolopyrrole was added to the pigment. These are referred to as resin-treated blue-3 (average particle size 29 nm), resin-treated green pigment-3 (average particle size 40 nm), and resin-treated red pigment-3 (average particle size 44 nm), respectively.

[ Reference Example 7]
270 parts of C-02 obtained in Synthesis Example 8, 1,000 parts of diketopyrrolopyrrole pigment (PR-254, average particle size 45 nm) paste (solid content 30%) as a refined red pigment, and 230 parts of ion-exchanged water was added, and 30 milled with a disper to prepare a mill base. Next, the pigment was sufficiently dispersed in a horizontal bead mill loaded with 0.5 mm zirconia beads. The average particle diameter of the pigment was 103 nm. To this mill base, 1,000 parts of pure water was added to obtain an aqueous pigment dispersion having a pigment content of 12%.

  Next, the mill base obtained above was poured into 5,000 parts of pure water, and 5% hydrochloric acid was added dropwise with high-speed stirring to precipitate an acrylic resin. At this time, the initial pH was 10.5, and it was lowered to pH 2.1 by adding an acid.

The solution was then filtered and washed thoroughly with pure water to obtain a pigment paste (solid content 30.0%). This paste was dried overnight at 50 ° C. in a vacuum dryer, pulverized, and a red pigment coated with a resin was obtained. This is designated as resin-treated red pigment-4.
In the same manner as described above, instead of C-02, the resin-treated red pigment-5 was obtained using C-03 obtained in Synthesis Example 9, and the resin-treated red pigment was used using C-04 obtained in Synthesis Example 10. Pigment-6 was obtained.

[Comparative Example 3]
A comparative resin-treated red pigment-1 was obtained in the same manner as in Reference Example 7 except that R-02 obtained in Comparative Synthesis Example 2 was used, and R-03 obtained in Comparative Synthesis Example 3 was used except that R-03 was used. Comparative resin-treated red pigment-2 was obtained in the same manner as in Reference Example 7.

[ Reference Example 8]
150 parts of D-01 obtained in Synthesis Example 12 (solid content 40%), 100 parts of diethylene glycol monobutyl ether, 200 parts of 5% aqueous sodium hydroxide and 580 parts of pure water were mixed to obtain a uniform solution. The solution was clear and free from precipitation and turbidity. This is a brominated copper phthalocyanine green pigment (PG-36, average particle size 51 nm) / nickel azo complex pigment (PY-150, average particle size 36 nm) = 52/48 which is a mixture of a green pigment and a complementary yellow pigment. A mill paste was prepared by adding 1,000 parts of a pigment paste (30% solid content) and peptizing with a disper for 2 hours.

  Next, the mill base obtained above was poured into 5,000 parts of pure water, and 5% hydrochloric acid was added dropwise with high-speed stirring to precipitate an acrylic resin. At this time, the initial pH was 11.0, and the pH was lowered to 2.6 by adding an acid. Next, the aqueous pigment dispersion was filtered, and a pigment paste (solid content 30.5%) obtained by thoroughly washing with pure water was obtained. This paste was dried in a vacuum dryer at 50 ° C. all day and night to obtain a yellow-green pigment coated with a resin. This is designated as resin-treated yellowish green pigment-1.

  The same as above except that C-01 obtained in Synthesis Example 7, D-02 obtained in Synthesis Example 13 and D-03 obtained in Synthesis Example 14 were used instead of D-01 used above. The operation was performed to obtain each yellow-green pigment treated with resin. These are referred to as resin-treated yellow-green pigment-2, resin-treated yellow-green pigment-3, and resin-treated yellow-green pigment-4, respectively.

  The acrylic resin-treated pigments (pigment compositions) obtained as described above are shown together in Tables 3 and 4. Table 5 summarizes the acrylic resin-treated pigments using the resins obtained in the comparative synthesis examples.

<Application to oil-based inkjet ink>
[Example 9]
(Preparation of pigment dispersion)
9 parts of a tree fat processing magenta pigment -1, polyester polyamide-based pigment dispersing agent (reaction product of polycaprolactone and polyethyleneimine to 12-hydroxystearic acid initiator, 45% solids) to 6 parts of PGMAc 15 parts The mixture was blended in a glass bottle and dispersed with zirconia beads for 2 hours using a paint shaker to obtain a magenta pigment dispersion. This is designated Magenta Pigment Dispersion-01. The average particle size of this pigment was measured and found to be approximately 102 nm. The viscosity of the pigment dispersion was also measured.

In the same manner as described above, tree butter processing cyan pigment -1, tree butter processed yellow pigments -2 using comparison resin treatment magenta pigment -1 to prepare a pigment dispersion of YMC colors. These are referred to as Cyan Pigment Dispersion-01, Yellow Pigment Dispersion-01, and Comparative Magenta Pigment Dispersion-01, respectively.

  The particle diameter and viscosity of the pigment dispersion immediately after the preparation were measured, and in addition, the pigment dispersion was allowed to stand in a constant temperature layer at 70 ° C. for 1 week, and then the particle diameter and viscosity were measured. The results are summarized in Table 6.

From Table 6, it was found that the acrylic resin-treated pigment (pigment composition) of the reference example was finely dispersed in a shorter time compared to the case where the resin-treated pigment of the comparative example was used. This is because the dispersion of the resin covering the pigment is very low (about 1.2) and does not contain a high molecular weight polymer, so that the acrylic resin is easily dissolved in the solvent. This is considered to be because the viscosity of the dispersion was lowered because it was easily compatible with the pigment and the pigment dispersant. Also, the stability of the dispersion was very high.

(Production of oil-based inkjet ink)
The pigment dispersions of the three types obtained in the above examples were used as oil-based ink-jet ink colors to make inks. Thereafter, the ink cartridge was filled, and solid printing was performed on the surface-treated 50 μm PET film by an ink jet printer. The obtained printed matter had a high optical density and a gloss value, had no printing twist, and had good scratch resistance.

<Application to inkjet ink for color filters>
[Example 10]
(Preparation of pigment dispersion)
Tree fat processed blue pigment -1, 90 parts of resin treatment red pigment -1, the resin treatment green pigment -1 respectively, 60 parts of the polyester polyamide pigment dispersant (45% solids) used in Example 9, and diethylene glycol 150 parts of monobutyl ether acetate (hereinafter abbreviated as BDGA) was blended, and after premixing, it was dispersed with a horizontal bead mill disperser. It was confirmed that the pigment could be easily dispersed, and pigment dispersions were obtained respectively. The results are summarized in Table 7.

  As in the case of Example 9, the viscosity of the pigment dispersion could be reduced by the narrow molecular weight distribution of the acrylic resin used and the low molecular weight component.

(Preparation of inkjet ink for color filter)
Using each of the above pigment dispersions, 70 parts thereof, 40 parts of BDGA, 2.5 parts of acrylic resin varnish, 4.5 parts of dipentaerythritol pentaacrylate, 2-hydroxy-2-methylpropiophenone 2 parts and 1 part of 2,2-diethoxyacetophenone were blended to obtain RGB inkjet ink for color filter.

  Using this as an ink-jet ink for a color filter, an RGB color filter was prepared and evaluated. Since the ink does not contain complementary colors, it cannot be said to be a reliable filter hue, but has excellent spectral curve characteristics, excellent fastness such as light resistance and heat resistance, and excellent contrast and light transmittance. It showed excellent properties as an image display.

<Application to UV curable inkjet ink>
[Example 11]
(Preparation of pigment dispersion)
Tree fat processing magenta pigment -2 resin treatment cyan pigment -2 and resin-treated yellow pigment -2 using comparison resin treatment magenta pigment -1 respectively, to obtain a pigment dispersion as follows. 75 parts of each resin-treated pigment, 97.5 parts of trimethylolpropane triacrylate, 112.5 parts of phenoxyethyl acrylate, and 15 parts of a polyester polyamide pigment dispersant were mixed and then dispersed in a horizontal bead mill disperser. . Then, each pigment dispersion was obtained by removing coarse particles with a centrifuge.

  Surprisingly, the comparative resin-treated magenta pigment-1 had a very high viscosity and gelled immediately after standing. Other pigment dispersions remained stable. This is considered to be lacking in stability because the acrylic resin used in the resin-treated pigment of the comparative example contains a high-molecular-weight resin with respect to a solvent having poor solubility as a monomer. In contrast, the acrylic resin used in the examples of the present invention is treated with a block copolymer having a polymer block, which has a narrow molecular weight distribution and a low content of high molecular weight components, and is particularly difficult to dissolve in a solvent. In Yellow-2, it is presumed that the insoluble polymer block promotes pigment adsorption and gives good dispersion.

(Preparation of UV curable inkjet ink)
Next, an ink jet ink was prepared as follows using each of the pigment dispersions of Examples obtained above. 30 parts of each pigment dispersion, 7.5 parts of urethane acrylate (manufactured by Kyoeisha Chemical Co., Ltd.), 69 parts of ethylene oxide-added trimethylolpropane triacrylate, 75 parts of 1,6-hexanediol diacrylate and photoinitiator 6 parts of benzyl dimethyl ketal was mixed and filtered through a 5 μm membrane filter to prepare an ultraviolet curable inkjet ink.

  Each ink obtained above was filled in an ink cartridge, solid-printed on a surface-treated 50 μm PET film with an inkjet printer, and then cured with a conveyor type ultraviolet irradiation device to obtain a printed matter. In the printing test, it was excellent in dischargeability and curability.

<Application to resist colors for color filters>
[Example 12]
(Preparation of pigment dispersion)
Tree fat processed blue pigment -2 using resin treatment red pigment -2 and resin-treated green pigment -2 respectively, to prepare a pigment dispersion. 90 parts of each resin-treated pigment, acrylic resin varnish (polymerized at a molar ratio of BzMA / MAA / HEMA = 70/15/15 /), 50 mol% of HEMA was reacted at MOI to introduce a methacryl group. Material: 90 parts of PGMAc solution having a molecular weight of 12,000, an acid value of 100, and a solid content of 40%, a polyester polyamide pigment dispersant (reaction product of polycaprolactone and polyethyleneimine with 12-hydroxystearic acid as an initiator, 60 parts of solid content (45%) and 150 parts of PGMAc were blended, and after premixing, the mixture was dispersed with a horizontal bead mill disperser to obtain a pigment dispersion. These were designated as pigment dispersion blue-2, pigment dispersion red-2, and pigment dispersion green-2. When the average particle diameter of this pigment was measured, all the average particle diameters were about 45 nm. Further, the viscosity of the pigment dispersion was measured. These results are summarized in Table 8.

  As shown in Table 8, the average particle diameter of the pigment in each of the obtained pigment dispersions was small and the viscosity was low. This is because the dispersion of the polymer obtained in the synthesis example of Examples is narrow and the high molecular weight component is small, so that the pigment is easily finely dispersed, and the pigment dispersion is also considered to have a low viscosity.

(Preparation of resist colors for color filters)
100 parts of each of the pigment dispersions of Examples obtained above, 50 parts of the acrylic resin varnish described above, 10 parts of trimethylolpropane triacrylate, 2 parts of 2-hydroxy-2-methylpropiophenone, 2, 2 -1 part of diethoxyacetophenone and 37 parts of PGMAc were blended to obtain an RGB resist color.

  Next, the glass substrate treated with the silane coupling agent was set on a spin coater, and the resulting resist color was spin-coated at 300 rpm for 5 seconds and then at 1200 rpm for 5 seconds. Next, prebaking was performed at 90 ° C. for 5 minutes. The obtained coating film was dissolved using a 0.1% aqueous potassium hydroxide solution, and the development behavior was visually evaluated for the time during which the resist composition was completely removed. The alkali developability test results are summarized in Table 9.

The coating film obtained by using the resin-treated pigment of Reference Example was developed in a predetermined time, and the development behavior was soluble and there was no dissolved residue. Moreover, when the coating film obtained from the resist color was dissolved using PGMAc, it rapidly dissolved and no insoluble residue remained.

[Example 13]
In the same manner as in Example 12, each of the blue, red, and green resin-treated pigments obtained in Reference Example 6 was applied to a resist color for a color filter in the same manner as described above. Obtained. Moreover, about each used pigment dispersion liquid, the storage stability for 1 week was confirmed at 70 degreeC. The results are shown in Table 10.

  This is thought to be due to the effective pigment adsorption in the ionic bond between the acid group of the synergist and the amino group of the acrylic resin, and improving the storage stability of the pigment dispersion.

<Application to resist colors for color filters 2>
[Example 14]
(Preparation of pigment dispersion)
Resin-treated red pigments -4 to 6 obtained in Reference Example 7, Comparative resin-treated red pigment-1 and Comparative resin-treated red pigment-2 in Comparative Example, and Resin-treated yellow-green pigments -1 to 4 obtained in Reference Example 8 Using each of the resin-treated pigments, a pigment dispersion was obtained as follows. 9 parts of each resin-treated pigment, 9 parts of the acrylic resin varnish described above, polyester polyamide pigment dispersant (reaction product of polycaprolactone and polyethyleneimine starting with 12-hydroxystearic acid, solid content 45%) 6 parts and 15 parts of PGMAc were blended, zirconia beads were added in a glass bottle and dispersed for 3 hours in a paint shaker. A red or green pigment dispersion was obtained. The average particle size and viscosity of this pigment were measured. This is summarized in Table 11.

As a result, it was found that the dispersion using the acrylic resin-treated pigment (pigment composition) of Reference Example gave a dispersion in which the pigment was easily finely dispersed. In the pigment dispersion of the present invention, it was confirmed that the average particle diameter of the pigment was smaller and the viscosity was lower than that of the comparative pigment dispersion. This is obtained A acrylic resin in Synthesis Example, narrow dispersity of molecular weight, because less high molecular weight components, easy pigment is finely dispersed, also pigment dispersion is considered to become a low viscosity.

  Using the above pigment dispersion, red and green resist colors were obtained in the same manner as in Example 12. Next, the glass substrate treated with the silane coupling agent was set on a spin coater, and the resulting resist color was spin-coated at 300 rpm for 5 seconds and then at 1200 rpm for 5 seconds. Then, prebaking was performed at 90 ° C. for 5 minutes. The obtained coating film was dissolved using a 0.1% aqueous potassium hydroxide solution, and the development behavior was visually evaluated for the time during which the resist composition was completely removed. The alkali developability test results are summarized in Table 12.

As shown in Table 12, the coating film obtained using the acrylic resin-treated pigment of the reference example was found to dissolve faster than the resist color using the acrylic resin of the comparative synthesis example. . Further, the development behavior was soluble and there was no dissolution residue. Further, in Red pigments 4 to 6, it was found that the molecular weight affected the development time even at the same acid value, and the development time could be adjusted by the molecular weight.
In addition, the yellow-green pigment using the block copolymer exhibited the same effect, and it was satisfactory without the development time being adjustable and the dissolution residue which is the insoluble part of the film. In addition, although the acid value as a whole is lower than that of red pigments 4 to 6, the acid value of one polymer block is high, so that the alkali development time is fast and development can be controlled. Clearly that PDI of A acrylic resin is narrow, it believed that the high molecular weight component is small is emitting effect.

<Application to polymerized toner>
[Example 15]
In a 1,000 ml beaker, 385 parts of water and 12.5 parts of polyvinyl alcohol (DP = 50, 98% saponification) were added and dissolved. 83 parts of styrene to another 300ml beaker, 17 parts of nBMA, tree butter processing magenta pigment 2 or resin treatment cyan pigment -2, or resin treatment yellow pigment -2, or a comparison resin treatment yellow pigment -1 respectively 10 parts and 1 part of AIBN were added, and the mixture was stirred at a high speed for 30 minutes at 1,000 rpm with a homogenizer to obtain monomer mixtures. At this time, the resin-treated pigment of the reference example was easily dissolved in the monomer, and no particulate matter remained at the bottom of the beaker. However, in the case of Comparative Resin-treated Yellow Pigment-1, it was difficult to dissolve in the monomer, and pulverized particles remained. Due to the narrow molecular weight distribution and the low molecular weight component of the acrylic resin used in the examples of the present invention, the resin-treated pigment of the reference example has poor solvent solubility, and is easily dissolved in styrene monomers and nBMA monomers. It is thought that the distributed state was given.

  Next, a beaker containing an aqueous polyvinyl alcohol solution was placed in a high-speed rotary stirrer, the monomer mixture was added, and the mixture was stirred at 2,000 rpm for 5 minutes. When this was sampled and observed with an optical microscope, a 5-10 μm spherical fine particle dispersion colored yellow was obtained. However, in the case of Comparative Resin-treated Yellow Pigment-1, pigment particles were precipitated and there were foreign matters. This is probably because the treated pigment of the comparative example is not well dispersed in the monomer.

  Subsequently, a stirrer, a backflow condenser and a thermometer were set, and polymerization was performed at 60 ° C. for 2 hours and at 80 ° C. for 3 hours. After cooling, it was filtered, then washed with hot water, dried and pulverized. Observation with an electron microscope and a Coulter counter revealed a fine particle shape of 5 to 10 μm. Moreover, there was almost no aggregate deposit, and there was no deposit of irregularly shaped particles other than a sphere or the pigment itself. Suspension polymerization was successfully performed and colored fine particles could be obtained.

  Colloidal silica was added thereto as a fluidizing agent, mixed with carrier magnetic iron powder, and copied as an electrophotographic dry developer using an electrophotographic copying machine, and a clear YMC color image was obtained. In Y, solid printing was performed, and the image was irradiated with ultraviolet rays for 8 hours using super UV, and a light resistance test was performed. As a result, there was almost no change in hue. This is presumably because the light resistance of the pigment is improved because the acrylic resin covering the pigment used for the yellow colored fine particles is an acrylic resin having ultraviolet absorption performance.

Pigments dispersions of the present invention, highly dispersible, storage stability, good printing state, a pigment dispersion provides good alkali developability, giving a high value to a colored article.

Claims (8)

Ing include organic pigment coated with an acrylic resin, it becomes dispersed in the organic solvent content of the Ru 5-95% by mass of acrylic resin-treated pigment composition of the organic pigment, the organic pigment Containing 10 to 100% by weight of a pigment dispersant ,
The acrylic resin is
1) 90% by mass or more of the monomer constituting the acrylic resin is a (meth) acrylate monomer (a), and 20% by mass or more of the (meth) acrylate monomer (a) is an aromatic ring or alicyclic. A (meth) acrylate monomer having an alkyl group,
2) The number average molecular weight in terms of polystyrene in the gel permeation chromatograph is 2,000 to 20,000, and the dispersity (weight average molecular weight / number average molecular weight) indicating the distribution of molecular weight is 1.4 or less. ,And,
3) A pigment dispersion having a glass transition temperature of 50 ° C. or higher. The pigment dispersion according to claim 1, wherein the pigment dispersant is at least one selected from the group consisting of a surfactant, an acrylic dispersant, an ester dispersant, and a urethane dispersant. The acrylic resin is an A-B block copolymer, at least one of the polymer blocks, according to claim 1 or 2 containing an aromatic ring or alicyclic alkyl groups (meth) acrylate monomer at least 30 mass% Pigment dispersion . The pigment dispersion according to any one of claims 1 to 3, wherein the acrylic resin further contains a (meth) acrylate monomer having a carboxyl group as a copolymerization component, and an acid value thereof is 30 to 250 mgKOH / g. The acrylic resin is an A-B block copolymer, the acid value of the A blocks constituting the A-B block copolymer is 50 to 250 mg / g, and the acid value of the B block 0~50mgKOH / g The pigment dispersion according to any one of claims 1 to 4 . Obtained the acrylic resin, the organic iodide and a polymerization initiator compound, phosphorus pulling the iodine from the organic iodide, nitrogen, an organic compound having an oxygen or carbon atom as a catalyst, by polymerizing the monomers using a radical generator pigment dispersion according to any one of claim 1 to 5 which is an acrylic resin. The catalyst is phosphorus halide containing iodine atom, phosphite compound, phosphinate compound, imide compound, hydantoin compound, phenol compound, iodooxyphenyl compound, vitamins, cyclohexadiene, diphenylmethane and iodine. The pigment dispersion according to claim 6 , which is at least one selected from the group consisting of fluorinated benzene. Colorant comprising a pigment dispersion according to any one of 請 Motomeko 1-7.

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