JP6059677B2 - Pigment dispersion, method for producing AB block copolymer used therefor, resin-treated pigment, and method for producing pigment dispersion - Google Patents

Description

  The present invention relates to a technique useful for finely dispersing a hardly dispersible pigment. Specifically, the present invention relates to a pigment dispersion using a novel AB block copolymer as a pigment dispersant, and an AB block copolymer used in the pigment dispersion. The present invention relates to a production method, a resin-treated pigment treated with the block copolymer, and a method for producing a pigment dispersion using the resin-treated pigment.

  In recent years, inks, paints, and coating agents used as image displays and image recording agents have been required to have high image quality, high image quality, and high printability, and as a result, pigments have been finely and uniformly finely dispersed. There is a need for pigment dispersions. Specific applications include color filter colorants, ultraviolet curable inkjet inks, and gravure inks. The pigment dispersion referred to in the present invention is a dispersion in which a pigment is dispersed in an organic solvent or a polymerizable compound. For example, a pigment dispersion in which a pigment is dispersed and contained in a high concentration is used as a colorant. By containing this in an oily medium, a product which is a pigment dispersion composition such as ink or paint in which the pigment is finely dispersed can be obtained.

  In the above inks and the like, a pigment dispersion is used as a pigment colorant. In particular, in the applications listed above, it is desired to highly disperse and maintain the pigment. For this reason, pigment dispersants having various structures have been developed, and the required performance is required to exhibit higher, fine dispersion, high stability, and high fluidity (for example, Patent Document 1, 2 and 3). One of these pigment dispersants uses an acrylic polymer. In the production method of an acrylic polymer, various living radical polymerization methods have been invented in order to control the structure. It is applied not only to pigment dispersants but also to the production of pressure-sensitive adhesives and elastomers (for example, Patent Document 4).

JP 2008-298967 A JP 2007-270089 A JP-A-9-176511 JP 2011-68865 A

However, although there are pigment types that can achieve these performances, there are pigments that are difficult to achieve fine dispersion and high storage stability, and their use may be limited. Such a pigment is a hydrogen bond type pigment that forms a crystal strongly by having a hydrogen bond in its molecule, and is a pigment that may be called a hardly dispersible pigment. Specifically, a carbonyl group (—C (═O) —) and an amino group (—NH ₂ , —NHR, —NRR ′) and these are bonded in a cyclic structure in the molecule such as a condensed polycyclic compound. It has an amide group (RCONH-), a ureido group (H ₂ NCONH-), and an imide group polar group, and when it becomes a pigment particle crystal, its carbonyl group and amino group are referred to as C = O ... HN. Hydrogen bonds are formed and the crystals are strong. These pigments sometimes have difficulty in obtaining fine dispersion and high storage stability due to their strong hydrogen bonds. Even for such difficult-to-disperse pigments that may be restricted in use, if good fine dispersion and storage stability become possible, realization of images and pixels of various desired tones, It is considered that it can cope with higher weather resistance of formed images and pixels, and is very useful.

  Therefore, the object of the present invention is to be able to finely disperse even the above-mentioned hardly dispersible pigments, and that the dispersed state does not change over time, and has a fine dispersion and high storage stability. It is to provide a pigment dispersion having excellent properties. In particular, an object of the present invention is to provide a new polymer dispersant capable of realizing the above excellent pigment dispersion.

  As a result of diligent research on the above problems, the inventors have found that an AB block copolymer satisfying a specific structure having a specific monomer component as a monomer unit only on one chain is used as a pigment dispersant or pigment. By using it as a surface treatment resin, it is possible to finely disperse pigments, in particular the above-mentioned difficultly dispersible pigments, and that the dispersed state does not change with time, and is highly dispersible. The present invention has been achieved by finding that storage stability is achieved. Furthermore, the present inventors have obtained a pigment dispersion obtained by finely dispersing the fine pigment, and when this is used as a colorant, the color development is good while maintaining high saturation, high transparency, and high gloss. The present inventors have found that it is possible to form high-quality images and pixels, and have reached the present invention.

The object of the present invention described above is achieved by the following present invention. That is, the present invention provides an AB block copolymer in which at least 90% by mass of a monomer unit constituting a polymer is a methacrylic acid monomer in a pigment dispersion having at least a pigment, a pigment dispersant, and an organic solvent. And only one polymer block (polymer block of B) constituting the AB block copolymer has, as a monomer unit, 2- (2-oxoimidazolidine- represented by the following formula (1): There is provided a pigment dispersion comprising 1-yl) ethyl methacrylate and having a cyclic ureido group introduced by the cyclic ureido methacrylate in the polymer block of B.

  The following are mentioned as a preferable form of the pigment dispersion liquid of the said invention. The pigment is an organic pigment having a carbonyl group and / or an amino group as an independent group in the cyclic structure in the molecule, or an amide group, a ureido group and a carbonyl group and an amino group bonded to each other. An organic pigment having at least one group selected from the group of imide groups; the organic solvent is an aprotic solvent, and a dielectric constant ε is 25 or less; In the case where a dye derivative having a group or a dye derivative having an acid functional group is included and the dye derivative has a basic functional group, the structure of the AB block copolymer is changed to the polymer block of B. Further includes, as a monomer unit, a methacrylic acid monomer having a carboxy group or a phosphate group, and a carboxy group or a phosphate group introduced by the monomer. In the case where the dye derivative has an acidic functional group, the AB block copolymer has a constitution in which the polymer block of B further includes a methacrylic acid monomer having an amino group as a monomer unit. The other polymer block constituting the AB block copolymer (A polymer block) has a polystyrene-reduced number average molecular weight of 1000 in the gel perchromatograph. And the dispersity (weight average molecular weight / number average molecular weight) indicating the molecular weight distribution is 1.5 or less, and the 2- (2-oxoimidazolidine-1- Yl) The content of ethyl methacrylate is 5 to 30% by mass, and the AB The number average molecular weight of the block copolymer is 3000 to 15000, and the degree of dispersion thereof is 1.6 or less; the pigment, the pigment dispersant, and the organic solvent are 5 to 20% by mass of the pigment. The pigment dispersant is blended within the range of 0.5 to 30% by mass and the organic solvent is within the range of 50 to 94.5% by mass; the pigment is a diketopyrrolopyrrole pigment, a quinophthalone pigment, and an anthraquinone pigment It is at least one selected from the group consisting of pigments; the AB block copolymer may be obtained by utilizing living radical polymerization using a polymerization initiating compound.

  The present invention also provides, as another embodiment, a method for producing an AB block copolymer for producing the AB block copolymer constituting the pigment dispersion described above, comprising at least a polymerization initiating compound and a catalyst. The polymerization initiator compound used in this step is at least one of iodine and iodine compound, and the catalyst used in this step is a phosphorus halide, phosphite system A method for producing an AB block copolymer, which is at least one compound selected from the group consisting of a compound, a phosphinate compound, an imide compound, a phenol compound, a diphenylmethane compound and a cyclopentadiene compound I will provide a.

  Another embodiment of the present invention is a resin-treated pigment obtained by treating a pigment with a pigment dispersant composed of an AB block copolymer to impart dispersibility to the pigment, and the pigment dispersant is any one of the above Resin treatment characterized in that it is an AB block copolymer constituting a pigment dispersion, and the AB block copolymer is contained in the range of 10 to 150 parts by mass with respect to 100 parts by mass of the pigment. Provide pigments.

  The present invention provides, as another embodiment, a method for producing a pigment dispersion for obtaining any one of the above pigment dispersions, wherein the resin-treated pigment is dispersed in an organic solvent. A method for producing a liquid is provided.

  The remarkable effect of the present invention is that an AB block copolymer having a ureido group introduced into one chain is converted into a pigment dispersant or the surface of a pigment only on one chain by using a specific monomer component as a monomer unit. It is obtained by using as a treatment resin. Specifically, having 2- (2-oxoimidazolidin-1-yl) ethyl methacrylate as the monomer component has a polymer block into which a specific group has been introduced (for convenience, the polymer block of B). By using the AB block copolymer as a pigment dispersant, the following remarkable effects are realized in the present invention. That is, an oxoimidazol-1-yl group (hereinafter referred to as a cyclic ureido group) introduced into the B chain by 2- (2-oxoimidazolidin-1-yl) ethyl methacrylate used in forming the polymer block of B. ) May form a hydrogen bond in the pigment, particularly in the pigment skeleton, having a carbonyl group and an amino group independently in the cyclic structure, or an amide group, a ureido group or an imide group in which a plurality of them are bonded. As a result, according to the present invention, fine dispersion and high storage stability can be achieved even for pigments that are considered to be difficult to disperse. It is possible to provide a pigment dispersion that achieves the above. The AB block copolymer characterizing the pigment dispersion of the present invention has a monomer unit composed of 90% by mass or more of a methacrylic acid monomer, and the other polymer block (referred to as polymer block A) has a cyclic ureido. Since the group is not introduced, the polymer block of A dissolves in the organic solvent used together, and steric hindrance and steric repulsion cause the pigment to be highly finely dispersed in the organic solvent and exhibit high storage stability. Is done.

  The remarkable effect of the present invention described above is that, as described above, the structure of the AB block copolymer constituting the pigment dispersant characterizing the present invention is introduced with a cyclic ureido group peculiar to the B polymer block. However, according to the study by the present inventors, the AB block copolymer having such a structure can be realized first by living radical polymerization of specific monomers defined in the present invention under specific conditions. It becomes possible to put it into practical use. That is, the living radical polymerization is capable of polymerizing a vinyl monomer having an acidic group or an amino group, but the living radical polymerization method utilized in the present invention does not require a special material. This is an easy polymerization method that can be achieved simply by adding a polymerization initiating compound and a catalyst to the radical polymerization, and because it does not require special production equipment or material purification, it is advantageous in terms of cost and environmentally friendly. There is.

  Next, the present invention will be described in detail with reference to preferred embodiments of the present invention. As a result of diligent investigations on the above-described problems of the prior art, the present inventors have found that an AB block copolymer having a unique structure formed by living radical polymerization can disperse a pigment that can solve the problems of the prior art. The present invention has been found by finding that it has extremely useful properties as an agent. More specifically, by using the pigment dispersant of the present invention made of the polymer, an excellent effect can be exerted with a small amount of addition to the pigment, and the pigment in the medium has high fine dispersibility and high stability. It has been found that a pigment dispersion can be realized that realizes all of the properties of the property and the high fluidity. In addition, products such as inks using this pigment dispersion as a pigment colorant, especially color resists and inkjet inks using color filter colorants, exhibit high image quality, high image quality, and high printability. The headline and the present invention were completed.

Hereinafter, the present invention will be described in more detail with reference to preferred embodiments.
The present invention relates to a pigment dispersion comprising at least a pigment, a pigment dispersant, and an organic solvent. The pigment dispersant is an AB block copolymer in which 90% by mass or more of the monomer units constituting the polymer is a methacrylic acid monomer. And one of the polymer blocks (B polymer block) constituting the copolymer has the following structure. That is, only the polymer block of B contains 2- (2-oxoimidazolidin-1-yl) ethyl methacrylate (hereinafter referred to as cyclic ureido methacrylate) represented by the following formula (1) as a monomer unit, It is an AB block copolymer having a cyclic ureido group introduced by cyclic ureido methacrylate in the polymer block of B.

  In the present invention, the pigment dispersed by the specific pigment dispersant described above is an organic pigment having a carbonyl group and / or an amino group as an independent group in the cyclic structure in the molecule, or When the pigment dispersion is an organic pigment having at least one group selected from the group consisting of an amide group, a ureido group, and an imide group bonded to an amino group, a more remarkable effect can be obtained. Furthermore, when the organic solvent used in combination with the pigment and the pigment dispersant is an aprotic solvent and the dielectric constant ε is 25 or less, a more remarkable effect can be obtained.

  As described above, the remarkable effect of the present invention is that the cyclic ureido group contained in the polymer block of B constituting the AB block copolymer characterizing the present invention strengthens the hydrogen bond with the pigment. It is obtained by promoting adsorption and acting to adsorb the polymer block of B to the pigment. Cyclic ureido groups are conventionally known, but are known to have an effect of improving adhesion to a substrate by hydrogen bonding. The polymer introduced with the cyclic ureido group greatly improves the adhesion to substrates such as alkyd resin, stainless steel, polyamide, and polyimide. This is because the adhesiveness is improved by the action of hydrogen bonds with the cyclic ureido groups of the polymers and the carboxyl groups, amide groups, ester groups, metal oxide groups, hydroxide groups of those base materials (for example, M .Okubo et.al Colloid Polym.Sci., 2003,282,88-91, Rhodia "Sipomer" technical catalog). By utilizing this action, the pigment having a functional group capable of hydrogen bonding and the cyclic ureido group contained in the polymer block B, which characterizes the present invention, are hydrogen-bonded, thereby providing a stronger adsorbability to the pigment. It is thought that it was realized.

  That is, the most technical feature of the present invention is that the cyclic ureido group introduced into the B chain of the AB block copolymer has a group capable of hydrogen bonding in the cyclic structure in the pigment, particularly the pigment skeleton. In the pigment dispersion liquid of the present invention, as a result that the other A chain has affinity with the organic solvent that is the dispersion medium, in addition to the fact that it is remarkably adsorbed by the action of hydrogen bonding with the pigment it has. High microdispersibility and high stability achieved.

  Furthermore, the organic solvent constituting the present invention is preferably an organic solvent that does not dissociate or break this hydrogen bond. For this purpose, the organic solvent is an aprotic solvent and has a dielectric constant ε of 25 or less. Preferably there is. In the case of a protic solvent, that is, a solvent having an active hydrogen such as a hydroxyl group, the hydrogen bond between the dispersant and the pigment characterizing the present invention is inhibited, and the hydrogen bond occurs between the organic solvent and the dispersant, the organic solvent and the pigment. , Which may inhibit the action of hydrogen bonding between the pigment and the dispersant characterizing the present invention. In addition, even when the dielectric constant is high, it may work in the direction of dissociating the hydrogen bond. Therefore, it is preferable that the solvent is as low as possible, specifically, the dielectric constant ε is 25 or less. Hereinafter, the pigment dispersant, the pigment, and the organic solvent constituting the pigment dispersion of the present invention will be described in detail.

  First, the AB block copolymer characterizing the present invention needs to contain 90% by mass or more of a structural unit derived from a methacrylic acid monomer, preferably 95% by mass or more, more preferably 100% by mass. It is. As will be described later, in the living radical polymerization, which is a suitable production method (polymerization method) of the AB block copolymer characterizing the present invention, it is particularly preferable to use a methacrylate monomer as a monomer. In contrast, in the production method described later, when vinyl monomers such as styrene, acrylate monomers, and vinyl ether monomers are used, iodine bonded to the polymerization terminal is over-stabilized and added to the dissociation. There is a possibility that inconveniences such as needing to be warmed or not dissociating occur. For this reason, when a monomer other than the methacrylate monomer is used in a large amount, there is a possibility that problems such as not having a specific structure intended in the present invention or widening the molecular weight distribution may occur. However, even if it is monomers other than a methacrylate monomer, you may use it in the range which does not impair the objective of this invention as needed.

  The AB block copolymer that characterizes the present invention is a block copolymer having a cyclic ureido group only in one polymer block. As described above, in the present invention, the polymer having this cyclic ureido group is conveniently used. Let the block be the polymer block of B. The AB block copolymer characterizing the present invention may be obtained by polymerizing the polymer block of A and then polymerizing the polymer block of B, or polymerizing the polymer block of B and then polymerizing the polymer block of A. More preferably, the polymer block of A is polymerized, and then the polymer block of B is polymerized to form an AB block copolymer. Although details of the polymerization method will be described later, when polymerizing one polymer block first using cyclic ureido methacrylate and then polymerizing by adding a monomer that forms the other polymer block, the polymer polymerized first If the polymerization rate of the block is low, the cyclic ureidomethacrylate may remain and be introduced into the polymer block polymerized later. In that case, since the cyclic ureido group is introduced into both polymer blocks, both of the polymer blocks are adsorbed to the pigment, and the effect of the present invention of fine dispersion and high storage stability cannot be sufficiently exhibited. Become. However, although it is complicated, the polymer block of B is first polymerized using cyclic ureidomethacrylate to eliminate residual monomers, particularly cyclic ureidomethacrylate, and then the polymer block of A is polymerized. It is also possible to form an AB block copolymer having a structure having a cyclic ureido group.

[Configuration of polymer block A]
First, in the AB block copolymer characterizing the present invention, the polymer block of A which is a polymer block having a function of dissolving and affinity in the organic solvent used together will be described. That is, while the polymer block of B introduced with a pigment-adsorbing cyclic ureido group is adsorbed to the pigment, the polymer block of A has affinity for and dissolves in an organic solvent, and aggregates the pigment by steric hindrance and steric repulsion It works to inhibit. Moreover, it has a property compatible with a pigment dispersion liquid and the other polymer component used according to a use.

  As described above, the monomer component constituting the polymer block of A is a methacrylic acid monomer as the main component, but the methacrylic acid monomer is not particularly limited, and one or more conventionally known monomers are used. The Specifically, for example, methyl methacrylate, ethyl methacrylate, propyl methacrylate, isopropyl methacrylate, butyl methacrylate, 2-methylpropane methacrylate, t-butyl methacrylate, pentyl methacrylate, hexyl methacrylate, octyl methacrylate, 2-ethylhexyl methacrylate, nonyl methacrylate, Decyl methacrylate, isodecyl methacrylate, lauryl methacrylate, tetradecyl methacrylate, octadecyl methacrylate, behenyl methacrylate, isostearyl methacrylate, cyclohexyl methacrylate, t-butylcyclohexyl methacrylate, isobornyl methacrylate, trimethylcyclohexyl methacrylate, cyclodecyl methacrylate Over DOO, cyclo decyl methacrylate, tricyclodecyl methacrylate, (cyclo) alkyl methacrylates such as benzyl methacrylate;

  Aryl methacrylates such as phenyl methacrylate and naphthyl methacrylate; alkenyl methacrylates such as allyl methacrylate; (poly) ethylene glycol monomethacrylate, (poly) propylene glycol monomethacrylate, (poly) ethylene glycol monomethyl ether methacrylate, (poly) ethylene glycol monoethyl ether Glycol monomethacrylates such as methacrylate, (poly) ethylene glycol monolauryl ether methacrylate, (poly) propylene glycol monomethyl ether methacrylate;

  Cyclic methacrylates such as tetrahydrofurfuryl methacrylate; halogen-containing methacrylates such as octafluorooctyl methacrylate and tetrafluoroethyl methacrylate; 2- (4-benzoxy-3-hydroxyphenoxy) ethyl methacrylate, 2- (2′-hydroxy-5- Examples include methacrylates that absorb ultraviolet rays such as methacryloyloxyethylphenyl) -2H-benzotriazole; silicon atom-containing methacrylates having a trimethoxysilyl group or a dimethylsilicone chain. Moreover, the macromonomer etc. which are obtained by introduce | transducing a (meth) acryl group into the one terminal of the oligomer obtained by superposing | polymerizing these monomers can be used.

  Moreover, the methacrylic acid type monomer which has a carboxy group can be used. For example, methacrylic acid; hydroxyl group-containing methacrylates such as 2-hydroxyethyl methacrylate and 2-hydroxypropyl methacrylate; dibasic acids such as phthalic acid, cyclohexanedicarboxylic acid, maleic acid, succinic acid, their acid anhydrides, and acid chlorides And half ester-type methacrylates of polycarboxy compounds such as dibasic acid and trimellitic acid obtained by reacting with. Moreover, you may use the methacrylate which has an isocyanate group, a glycidyl group, an amino group etc. which are reactive functional groups as needed.

[Configuration of polymer block B]
Next, in the AB block copolymer used in the present invention, the polymer block of B into which the cyclic ureido group characterizing the present invention is introduced by using the cyclic ureido methacrylate having the specific structure described above will be described. This polymer block of B is a polymer block showing a strong hydrogen bond derived from the introduced cyclic ureido group, and is a polymer block having a function of adsorbing by hydrogen bonding to the pigment or encapsulating. Since it is essential that a cyclic ureido group is introduced into this polymer block, in the present invention, 2- (2-oxoimidazo) represented by the following formula (1) is used as the methacrylate having the cyclic ureido group. It was essential to use at least lysine-1-yl) ethyl methacrylate (cyclic ureido methacrylate) as a constituent.

  The methacrylate having a cyclic ureido group has various structures. For example, a reactive methacrylic acid monomer such as methacrylic acid chloride, methacrylic anhydride, glycidyl methacrylate or methacryloyloxyethyl isocyanate is reacted with aminobenzimidazole or 2- (2-oxoimidazolidin-1-yl) ethanol. Can also be used in the present invention. However, in this case, a separate monomer manufacturing process is required. In addition, there is a possibility that it may become a new substance in the recent worldwide chemical regulations, which entails enormous costs for registration. From the viewpoint, the cyclic ureido methacrylate defined in the present invention that is commercially available and used conventionally is very suitable. One feature of the present invention is the use of this cyclic ureido methacrylate.

  That is, it is essential to polymerize a monomer component containing at least the above-described cyclic ureidomethacrylate to form a polymer block of B, as long as it has the above-mentioned specific cyclic ureidomethacrylate. It is good also as a polymer block of B by copolymerizing. Although mentioned later, it is preferable that content of the above-mentioned specific cyclic ureido methacrylate in the polymer block of B is 5-30 mass%.

[About pigments]
Next, the pigment used for the pigment dispersion will be described. Examples of the pigment used in the present invention include organic pigments, inorganic pigments, metal pigments such as metal powders or fine particles, and inorganic fillers. The organic pigment is not limited in its crystal state, mixed crystal, solid solution and the like. Specific examples of organic pigments and inorganic pigments include quinacridone pigments, anthraquinone pigments, diketopyrrolopyrrole pigments, perylene pigments, phthalocyanine blue pigments, phthalocyanine green pigments, isoindolinone pigments, indigo thioindigo pigments. , Dioxazine pigment, quinophthalone pigment, nickel azo pigment, insoluble azo pigment, soluble azo pigment, high molecular weight azo pigment, carbon black pigment, composite oxide black pigment, iron oxide black pigment, titanium oxide black pigment, azomethine azo And red, green, blue, yellow, orange, purple, black and white pigments selected from the group consisting of black pigments and titanium oxide pigments. Specific examples of metal pigments include copper powder and aluminum flakes. Specific examples of the inorganic filler include mica pigments, natural minerals and silica. The average particle diameter of these pigments is not particularly limited, but preferably the average primary particle diameter is less than 150 nm for organic pigments and less than 300 nm for inorganic pigments and fillers.

  As described above, in particular, the pigment used in the present invention is hydrogen bonded to the cyclic ureido group contained in the polymer block of B characterizing the present invention, in that the effect of the present invention is obtained more remarkably. A pigment having a group is preferred. Specifically, an organic pigment having a carbonyl group and / or an amino group as an independent group in a cyclic structure in the molecule, or an amide group, a ureido group and an imide group in which a carbonyl group and an amino group are bonded. Organic pigments having at least any group are particularly preferred. These pigments have strong crystals due to strong hydrogen bonds, and are known as hardly dispersible pigments. In order to disperse such a hardly dispersible pigment, the cyclic ureido group contained in the polymer block of B of the present invention which is a hydrogen bond and has a similar structure exhibits a good pigment adsorbing property. It is considered that pigment fine dispersibility and high storage stability, which are remarkable effects of the invention, can be achieved.

  The organic pigment having a carbonyl group and an amino group independently or as an amide group, a ureido group, and an imide group in a cyclic structure in a molecule that exhibits a more remarkable effect by the present invention includes, for example, many Examples thereof include a ring-condensed pigment, a heterocyclic pigment, and a pigment having a cyclic ureido group. More specifically, the following diketopyrrolopyrrole pigments, quinacridone pigments, isoindoline pigments, isoindolinone pigments, quinophthalone pigments, anthraquinone pigments, indanthrone pigments, benzimidazolones This applies to pigments.

  The diketopyrrolopyrrole pigment is a pigment having a structure represented by the following formula (2). Specifically, pigment red 254, pigment red 255, pigment red 264, pigment red 283, pigment orange 71, pigment orange 73 Etc.

（Ｒ、Ｒ’は任意の有機基であって、同じであっても異なっていてもよい。ｍ、ｎはそれぞれ独立に０〜５の数を示し、その置換基の数を示す。なお、ｍ、ｎが０の場合は置換していないことを示す。）

(R and R ′ are arbitrary organic groups which may be the same or different. M and n each independently represent a number of 0 to 5 and the number of substituents thereof. (When m and n are 0, it indicates that no substitution is performed.)

  The quinacridone pigment is a pigment having a structure represented by the following formula (3). Specific examples include Pigment Violet 19, Pigment Red 122, Pigment Red 202, Pigment Red 209, Pigment Orange 48, and Pigment Orange 49. It is done.

（Ｒ、Ｒ’は任意の有機基であって、同じであっても異なっていてもよい。ｍ、ｎはそれぞれ独立に０〜４の数を示し、その置換基の数を示す。なお、ｍ、ｎが０の場合は置換していないことを示す。）

(R and R ′ are arbitrary organic groups which may be the same or different. M and n each independently represent the number of 0 to 4, and the number of substituents thereof. (When m and n are 0, it indicates that no substitution is performed.)

（Ｒ₁〜Ｒ₄は、少なくとも１個がカルボニル基を有する有機基であり、その他の置換基は任意の有機基であり、同じであっても異なっていてもよい） The isoindoline pigment is a pigment having a structure represented by the following formula (4), and specifically includes Pigment Yellow 139, Pigment Yellow 185, Pigment Red 260, Pigment Orange 66, Pigment Orange 69, Pigment Brown 38, and the like. Can be mentioned.

(At least one of R _{1 to} R ₄ is an organic group having a carbonyl group, and the other substituents are arbitrary organic groups, which may be the same or different.)

（Ｒ、Ｒ’は任意の有機基であって、同じであっても異なっていてもよい。ｍ、ｎはそれぞれ独立に０〜４の数を示し、その置換基の数を示す。なお、ｍ、ｎが０の場合は置換していないことを示す。また、Ｘは任意の連結可能な有機基を示す。） The isoindolinone pigment is a pigment having a structure represented by the following formula (5), and specific examples thereof include pigment yellow 109, pigment yellow 110, pigment orange 61, pigment yellow 177, and pigment yellow 179.

(R and R ′ are arbitrary organic groups which may be the same or different. M and n each independently represent the number of 0 to 4, and the number of substituents thereof. When m and n are 0, it indicates that they are not substituted, and X represents any connectable organic group.)

（Ｒは任意の有機基であり、ｎ＝０〜４の数を示し、その置換基の数を示す。なお、０の場合は置換していないことを示す。また、Ｙは、水素原子であるか、任意の有機基を示す。） The quinophthalone pigment is a pigment having a structure represented by the following formula (6), and specific examples include pigment yellow 138, pigment yellow 139, and pigment yellow 185.

(R is an arbitrary organic group, n represents the number of 0 to 4, and represents the number of substituents. In the case of 0, it indicates that the substituent is not substituted. Y represents a hydrogen atom. Or any organic group.)

（Ｚは、水素または任意の有機基を示す。） An anthraquinone pigment is a pigment having a structure represented by the following formula (7), and specific examples include Pigment Red 83, Pigment Red 89, and Pigment Red 177.

(Z represents hydrogen or any organic group.)

The indanthrone pigment is a pigment having a structure represented by the following formula (8), and specific examples include Pigment Blue 60.

（Ａは、構造中に−Ｎ＝Ｎ−であるアゾ基を有する任意の有機基を示す。） The benzimidazolone pigment is a pigment having a structure represented by the following formula (9) or the following formula (10). Specifically, pigment yellows 120, 151, 154, 175, 176, 150, 181, 185, 194, Pigment Red 185, 280 and the like.

(A represents an arbitrary organic group having an azo group with —N═N— in the structure.)

[About organic solvents]
Next, the organic solvent used for the pigment dispersion will be described. As the organic solvent used in the present invention, the following can be used. That is, hydrocarbon solvents such as hexane, octane, decane, isodecane, cyclohexane, methylcyclohexane, toluene, xylene, and ethylbenzene; alcohols such as methanol, ethanol, propanol, isopropanol, butanol, isobutanol, hexanol, benzyl alcohol, and cyclohexanol Solvents: ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, methyl cellosolve, ethyl cellosolve, butyl cellosolve, propylene glycol monomethyl ether, propylene glycol monoethyl ether, diethylene glycol methyl ether ether, propylene glycol propyl ether, diglyme, triglyme, tetra Glyme and diplopilling lily Glycol solvents such as dimethyl ether, butyl carbitol, butyl triethylene glycol, methyl dipropylene glycol, methyl cellosolve acetate, propylene glycol monomethyl ether acetate, dipropylene glycol butyl ether acetate, diethylene glycol monobutyl ether acetate; diethyl ether, dipropyl ether Ether solvents such as methylcyclopropyl ether, tetrahydrofuran, dioxane, anisole; ketone solvents such as methyl ethyl ketone, diethyl ketone, methyl isobutyl ketone, cyclohexanone, isophorone, acetophenone; methyl acetate, ethyl acetate, butyl acetate, propyl acetate, butyric acid Methyl, ethyl butyrate, caprolactone, methyl lactate, lactate ester Ester solvents such as dimethyl oxalate, dimethyl malonate, dimethyl adipate and dimethyl glutarate; halogenated solvents such as chloroform and dichloroethane; amides such as dimethylformamide, dimethylacetamide, pyrrolidone, N-methylpyrrolidone and caprolactam In addition to the solvent, dimethyl sulfoxide, sulfolane, tetramethylurea, ethylene carbonate, propylene carbonate, dimethyl carbonate, and polymerizable monomers such as (meth) acrylate and vinyl ether can be used as the organic solvent for the dispersion medium. In addition, these organic solvents can be used individually by 1 type or in combination of 2 or more types.

  More preferably, the organic solvent used in the present invention is an aprotic solvent and has a dielectric constant ε of 25 or less. This is because when a protic solvent, that is, an organic solvent showing a hydrogen bond such as a hydroxyl group or a carboxy group, which is an active hydrogen, is used, the hydrogen bond between the cyclic ureido group of the dispersant of the present invention and the pigment is inhibited. The cyclic ureido group of the solvent and the dispersant, the hydrogen bond between the organic solvent and the pigment works preferentially, the hydrogen bond between the cyclic ureido group and the pigment according to the present invention is not achieved, and the fine dispersibility, which is the effect of the present invention, is high. Storage stability may not be obtained. In addition, when the dielectric constant is high, dissociation of hydrogen bonds is promoted, and the same effect may not be observed. Therefore, in the present invention, the dielectric constant ε, which is an aprotic polar solvent and has a relatively low dielectric constant, is preferably 25 or less. When the dielectric constant is 25 or more, it is considered that dissociation of hydrogen bonds is promoted. More preferably, the dielectric constant ε is 20 or less.

  Specific examples of the aprotic polar solvent having a dielectric constant ε of 25 or less include alkanes such as hexane, toluene and xylene, aryl hydrocarbon solvents, ketone solvents such as methyl ethyl ketone and cyclohexanone, and butyl acetate. Examples include ester solvents, glycol ether ester solvents such as propylene glycol monomethyl ether acetate and propylene glycol monobutyl ether acetate, ether solvents such as tetrahydrofuran, and polymerizable monomers such as isobornyl acrylate are also dispersion media. Used as an organic solvent. These are organic solvents having an alkyl having 2 or more carbon atoms, an aryl, its carbonyl group, an ester group, or an ether group. One or more of these are used.

  As described above, the pigment dispersion of the present invention comprises the above-described pigment, a pigment dispersant composed of a specific AB block copolymer, and an organic solvent. The thing containing a pigment | dye is mentioned. Hereinafter, the pigment dispersion having such a structure will be described in detail. The pigment dispersion is divided into a case where the dye derivative has a derivative basic functional group and a case where the pigment derivative has an acid basic functional group. The constitution of the polymer block of B of the specific AB block copolymer characterizing the present invention to be contained as an agent is constituted as follows.

  Specifically, when the pigment derivative has a basic functional group, the AB block copolymer has a constitution in which the B polymer block into which the specific cyclic ureido group is introduced is a monomer unit, It includes a methacrylic acid monomer having a carboxy group or a phosphate group, and has a carboxy group or a phosphate group introduced by the monomer.

  Further, when the dye derivative has an acidic functional group, the AB block copolymer has a constitution in which the polymer block of B into which a specific cyclic ureido group has been introduced is further added as an amino group. And having an amino group introduced by the monomer.

  In the present invention, as described above, the polymer block of B is adsorbed to the pigment by the hydrogen bond between the cyclic ureido group and the pigment to obtain a good pigment dispersion. High pigment dispersibility and high storage stability can be obtained. As described above, in addition to the hydrogen bond between the cyclic ureido group and the pigment, by further introducing an acidic group or amino group into the polymer block of B, when the polymer block of B is an acidic group on the surface of the pigment, A pigment derivative (basic synergist) having a basic group is adsorbed to a pigment derivative (acid synergist) having an acidic group when the polymer block of B is basic. By introducing an ionic group or an acidic group and ion-bonding the B polymer block and the pigment, stronger pigment adsorption is achieved, and high fine dispersion and high storage stability are achieved. As described above, the pigment dispersion of the present invention has the above-described configuration, so that, among the pigments, an amide group and a ureido group in which a carbonyl group and an amino group are bonded independently or in a cyclic structure in the molecule. This is particularly effective when an organic pigment having a group or an imide group is used. Hereinafter, in the present invention, a dispersant having an acidic group introduced into the B polymer block is referred to as an acidic dispersant, and a dispersant having a basic group introduced into the B polymer block is referred to as a basic dispersant.

  The dye derivative is the same as the structure of the pigment; the structure similar to the structure of the pigment; the same or similar to the raw material for forming the pigment, for example, azo dye skeleton, phthalocyanine dye skeleton, anthraquinone A dye skeleton, a triazine dye skeleton, an acridine dye skeleton, a perylene dye skeleton, and the like, and one or more functional groups are bonded to a part of the structure. Although it may be directly bonded to the dye skeleton, it may be bonded to the dye skeleton via a hydrocarbon group such as an alkyl group or an aryl group; an ester, ether, sulfonamide, or urethane bond. Although the similar structure of the pigment used for this invention is preferable, it does not specifically limit. These pigment derivatives are added at the time of pigment synthesis, pigment crystallization, or pigment refinement, and have the same or similar structure as the pigment, so that they can be adsorbed on the pigment surface to functionalize the pigment surface. it can. The amount of the pigment derivative is 3 to 50% by mass, more preferably 5 to 30% by mass, based on the pigment. These are conventionally known compounds, surface treatment methods and addition amounts, and are not particularly limited. In the present invention, this dye derivative may be treated as a part of the pigment, and the pigment treated with the dye derivative may be used as the pigment.

[Combination of basic synergist and acidic dispersant]
First, a pigment derivative having a basic group (basic synergist) will be described. Examples of the dye derivative having a basic group include compounds in which one or more basic groups are substituted and bonded to the dye skeleton. In the present invention, for example, a dye derivative having a functional group whose basic group is an amino group can be used. The amino group is not particularly limited, and is an amino group of a primary amino group, a secondary amino group, or a tertiary amino group, and includes a quaternary ammonium salt. Particularly preferably, it is a secondary amino group to which an alkyl group having 4 or more carbon atoms or a cycloalkyl group is bonded, and examples thereof include a t-butylamino group and a cyclohexylamino group, and further an alkyl group having 1 to 10 carbon atoms. A bonded tertiary amino group, for example, dimethylamino group, diethylamino group, dibutylamino group and the like.

  As defined in the present invention, an acidic dispersant having an acidic group in the adsorbing polymer block, that is, the B polymer block, is used as the pigment dispersant for such a basic synergist. As the acidic dispersant, in addition to the constitution of the pigment dispersant described above, a cyclic ureido group which is a feature of the present invention is introduced into the polymer block of B, and a carboxy group or a phosphate group is included as an acidic group. A copolymerized methacrylic acid monomer is used. As the methacrylic acid monomer having a carboxy group used in this case, those described above can be used. Examples of the methacrylic acid monomer having a phosphoric acid group include 2- (methacryloyloxy) ethyl phosphate, 3-chloro-2- (phosphonooxy) propyl methacrylate, 2- (methacryloyloxy) propyl phosphate, and methacrylic acid 2 Examples include-(phenoxyphosphonyloxy) ethyl, acid phosphooxypolyoxyethylene glycol monomethacrylate, and acid phosphooxypolyoxypropylene glycol monomethacrylate. Bifunctional methacrylates such as bis (2-methacryloyloxyethyl phosphate) can also be used as long as they do not gel, but are not particularly limited. This acidic carboxy group or phosphate group is ionically bonded to the amino group of the basic synergist, and exhibits higher adsorptivity due to hydrogen bonding with the cyclic ureido group, resulting in high fine dispersion. And high dispersion stability. In the present invention, the polymer block B may be composed of only cyclic ureidomethacrylate and a methacrylic acid monomer having an acidic group, but may be copolymerized with the other methacrylic monomers described above. Further, the amount of the acidic group is not limited.

[Combination of acidic synergist and basic dispersant]
Next, a case where a pigment derivative having an acidic group and an acidic synergist are used will be described. Examples of the dye derivative having an acidic group include compounds in which one or more acidic groups are substituted and bonded to the above-described dye skeleton. The acidic group is, for example, a carboxy group, a phosphoric acid group, or a sulfonic acid group, and these groups are not limited. However, a sulfonic acid group that is strongly basic in order to strengthen ion adsorption is preferred.

  Next, when such an acidic synergist is used, a basic dispersant having an acidic group in the adsorptive polymer block, that is, the polymer block of B, is used as the pigment dispersant. As the basic dispersant used in this case, in addition to the constitution of the pigment dispersant described above, a cyclic ureido group, which is a feature of the present invention, is introduced into the polymer block B, and an amino group is included as a basic group. A copolymerized methacrylic acid monomer is used. The amino group is not particularly limited, and is an amino group of a primary amino group, a secondary amino group, or a tertiary amino group, and includes a quaternary ammonium salt. Particularly preferred is a secondary amino group to which an alkyl group having 4 or more carbon atoms or a cycloalkyl group is bonded, such as a t-butylamino group, and further an alkyl group having 1 to 10 carbon atoms being bonded. A tertiary amino group, for example, a dimethylamino group, a dietalamino group, and the like. These tertiary amino groups may be quaternized with benzyl chloride or the like. Examples of the methacrylic acid monomer having an amino group include dimethylaminoethyl methacrylate, diethylamino methacrylate, and t-butylamino methacrylate. The polymer block of B may be composed of only cyclic ureido methacrylate and a methacrylic acid monomer having an amino group, but may be copolymerized with the methacrylic acid monomer described above. Further, the amount of the amino group is not limited. This basic group, which is an amino group, is ion-bonded to the acid group of the acid-based synergist and has a high adsorptivity due to the hydrogen bond with the cyclic ureido group. It shows dispersion stability.

[Preferred form of AB block copolymer]
As the above-described pigment dispersant, a more preferable configuration of the AB block copolymer characterizing the present invention used as an acidic dispersant or a basic dispersant will be described. The polymer block of A that does not have the cyclic ureido methacrylate defined in the present invention as a monomer unit has a number average molecular weight (hereinafter abbreviated as Mn) in terms of polystyrene in its gel perchromatograph (hereinafter abbreviated as GPC) of 1000 to 10,000. And the dispersity (weight average molecular weight / number average molecular weight, hereinafter abbreviated as PDI) indicating the molecular weight distribution is preferably 1.5 or less. Further, in the other polymer block B, the content of the specific cyclic ureido methacrylate represented by the following formula (1) as the monomer unit in the polymer block of B is preferably 5 to 30% by mass. .

  As a more preferable constitution of the AB block copolymer characterizing the present invention, in addition to the above, the number average molecular weight of the AB block copolymer is 3000 to 15000 and the dispersity is 1.6 or less. Is preferred. Hereinafter, each of the above requirements will be described.

  First, as described above, it is preferable that the polymer block A having solubility in an organic solvent has Mn of 1000 to 10,000 and PDI of 1.5 or less. In the pigment dispersion of the present invention, the polymer block A constituting the AB block copolymer as the pigment dispersant is repelled by being dissolved in the organic solvent after the other polymer block B is adsorbed on the pigment. Dispersion stabilization is performed. In this case, if the Mn of the polymer block of A is less than 1000, sufficient repulsion cannot be obtained and the pigment may be aggregated, which is not preferable. On the other hand, if Mn exceeds 10,000, the viscosity may increase after dissolution, which is not preferable. More preferably, Mn of the polymer block of A is 2000 to 8000. In addition, the PDI of the polymer block of A is preferably 1.5 or less. This is an index indicating the variation in molecular weight. When it is 1, the molecular weight is completely the same, and a larger value indicates that the molecular weight is smaller to larger. Here, a PDI of 1.5 or less indicates that the molecular weight is relatively uniform and does not include a large molecular weight or a small molecular weight. This affects the molecular weight range described above, and it is preferable that the molecular weight distribution is narrow so as not to include a small molecular weight, specifically less than 1000, a large molecular weight, specifically greater than 10,000. More preferably, it is 1.3 or less.

  The other B polymer block constituting the AB block copolymer used as a dispersant in the pigment dispersion of the present invention is formed by a monomer containing a specific cyclic ureido methacrylate as defined in the present invention. It is preferable that content of the specific cyclic ureido methacrylate contained in the polymer block is 5 to 30% by mass. If it is less than 5%, sufficient hydrogen bonding may not be exhibited and storage stability may not be exhibited, and if it exceeds 30% in the polymer block of B, it dissolves in the aprotic polar solvent which is the organic solvent described above. May not. More preferably, it is 10-20 mass%.

  Moreover, it is preferable that AB block copolymer used suitably as a dispersing agent in the pigment dispersion liquid of the present invention has Mn of 3000 to 15000 and PDI of 1.6 or less. When Mn is smaller than 3000, the molecular weight of the polymer block B is smaller than 1000 when judged from the molecular weight of the polymer block A described above. That is, the molecular weight of the B polymer block is calculated by subtracting the Mn of the A polymer block from the Mn of the AB block copolymer, and this is used as the number average molecular weight of the B polymer block. If the number average molecular weight of the polymer block of B is less than 1000, it is not preferable because the adsorptivity of the pigment is weak and fine dispersion and storage stability may not be exhibited. On the other hand, if the molecular weight of the AB block copolymer is greater than 15000, the number of dispersant molecules may be small relative to the amount added, and a large amount of dispersant relative to the pigment may be required. More preferably, Mn is 5000-12000. Further, the PDI is 1.6 or less, and the molecular weight is relatively uniform. As described above, if the distribution is wider than 1.6, it may contain a molecular weight outside the range of the present invention, which is not preferable. Preferably it is 1.55 or less, More preferably, it is 1.5 or less.

[Method for Producing AB Block Copolymer]
The AB block copolymer characterizing the present invention is preferably obtained by the following polymerization method. As described above, the AB block copolymer that characterizes the present invention is an AB block copolymer having a molecular weight in a specific range and a uniform distribution. As a method for obtaining such a polymer, It is preferable to use a living radical polymerization method. As the living radical polymerization for obtaining the AB block copolymer of the present invention, the following method is preferred. Specifically, the living radical polymerization used in the present invention includes a step of living radical polymerization of a monomer component containing the above-mentioned methacrylate monomers in the presence of a polymerization initiating compound and a catalyst. The polymerization initiating compound is at least one of iodine and iodine compound, and the catalyst is phosphorus halide, phosphite compound, phosphinate compound, imide compound, phenol compound, diphenylmethane compound, and cyclopentadiene compound. It is preferably at least one compound selected from the group consisting of

  Here, various methods have been invented as living radical polymerization. For example, using a nitroxide method (NMP method) that utilizes dissociation and bonding of amine oxide radicals, heavy metals such as copper, ruthenium, nickel, and iron, and a ligand that forms a complex with these heavy metals, halogens are used. Atom transfer radical polymerization (ATRP method), which uses a compound as the starting compound, dithiocarboxylic acid ester, xanthate compound, etc. are used as the starting compound, and an addition polymerizable monomer and a radical initiator are used. Reversible addition-fragmentation chain transfer (RAFT method) and MADIX (Macromolecular Design via Interchange of Xanthate), organic tellurium, organic bismuth, organic antimony, antimony halide, organic germanium, Halogenated gel A method of using a heavy metal bromide such as (Degenerative transfer: DT method). These methods also use a polymerization initiating compound and can be applied to the present invention.

  However, the above-described method has a problem in easily and stably obtaining the AB block copolymer characterizing the present invention. For example, in the NMP method, an amine oxide such as a tetramethylpiperidine oxide radical is used, but it is necessary to polymerize under a high temperature condition of 100 ° C. or higher. There is also a problem of not progressing.

  In the ATRP method, it is necessary to use a heavy metal, and since it is a polymerization method accompanied by redox, it is necessary to remove oxygen, and in the method of polymerizing by forming a complex using an amine compound as a ligand, an acidic substance is added to the polymerization system. Since the formation of the complex is hindered in the presence of the acid, it is difficult to polymerize the addition polymerizable monomer having an acid group as it is. Although it is necessary to polymerize the monomer which protected the acid group with the protecting group and to remove the protecting group after the polymerization, it is complicated and it is not easy to introduce the acid group into the polymer block.

  In the RAFT method and the MADIX method, first, special compounds such as a dithiocarboxylic acid ester and a xanthate compound are required. Since these are sulfur-based compounds, an unpleasant sulfur-based odor tends to remain in the obtained polymer. Sometimes it is colored. For this reason, it is necessary to remove an odor and coloring from the obtained polymer. Polymerization of methacrylate monomers may not be successful. In addition, sulfur esters such as dithiocarboxylic acid esters and xanthate compounds may be decomposed by amino groups, resulting in a polymer having a low molecular weight or a sulfur odor.

  Furthermore, in the DT method, it is necessary to use heavy metals as in the ATRP method. For this reason, there is a problem that it is necessary to remove heavy metals from the obtained polymer and to purify waste water containing the generated heavy metals.

  For the above situation, in the polymerization method defined in the present invention for obtaining an AB block copolymer suitable for the present invention, the use of heavy metal compounds is not essential, and purification of the polymer is not essential. Is very useful because it can be easily manufactured by using a relatively inexpensive material on the market. Furthermore, this method is a method in which the polymerization conditions are mild, and the polymerization can be performed under the same conditions as the conventional radical polymerization method. It should be noted that a monomer having a carboxy group or the like can be directly subjected to living radical polymerization. It is in.

  In the production method of the present invention for producing an AB block copolymer suitable for the present invention, as described above, a step of living radical polymerization of a monomer component containing a methacrylate monomer in the presence of a polymerization initiating compound and a catalyst. (Polymerization process) is used, and at least one of iodine and an iodine compound is used as the polymerization initiating compound. In this living radical polymerization, various functional groups can be used as described later.

  In the polymerization step, at least one of iodine and an iodine compound is used as a polymerization initiating compound, and a monomer component containing a methacrylate monomer is polymerized by living radical polymerization, and the reaction at that time proceeds as follows. First, when heat or light is applied to iodine or iodine compound used as a polymerization initiating compound, iodine radicals are dissociated. Then, after the monomer is inserted in a state in which the iodine radical is dissociated, the iodine radical is immediately bonded again to the polymer terminal radical and stabilized, and the polymerization reaction proceeds while preventing the termination reaction.

  Specific examples of the iodine compound used above include alkyl iodides such as 2-iodo-1-phenylethane and 1-iodo-1-phenylethane; 2-cyano-2-iodopropane, 2-cyano-2- Cyano group-containing iodine such as iodobutane, 1-cyano-1-iodocyclohexane, 2-cyano-2iodo-2,4-dimethylpentane, 2-cyano-2-iodo-4-methoxy-2,4-dimethylpentane And the like.

  As these iodine compounds, commercially available products may be used as they are, but those prepared by a conventionally known method can also be used. For example, an iodine compound can be obtained by reacting an azo compound such as azobisisobutyronitrile with iodine. Further, the iodine compound can be obtained by reacting an organic halide obtained by substituting iodine of the above iodine compound with a halogen atom such as bromine or chlorine and an iodide salt such as quaternary ammonium iodide or sodium iodide, and exchanging the halogen. Can be obtained.

  In the polymerization step, a catalyst that can further extract iodine from the polymerization initiating compound may be used together with the polymerization initiating compound. Examples of catalysts include phosphorus compounds such as phosphorus halides, phosphite compounds, and phosphinate compounds; nitrogen compounds such as imide compounds; oxygen compounds such as phenol compounds; diphenylmethane compounds and cyclopentadiene compounds. It is preferable to use the following hydrocarbon compound. In addition, these catalysts can be used individually by 1 type or in combination of 2 or more types.

  Specific examples of the phosphorus compound include phosphorus triiodide, diethyl phosphite, dibutyl phosphite, ethoxyphenyl phosphinate, and phenylphenoxy phosphinate. Specific examples of the nitrogen compound include succinimide, 2,2-dimethylsuccinimide, maleimide, phthalimide, N-iodosuccinimide, and hydantoin. Specific examples of the oxygen-based compound include phenol, hydroquinone, methoxyhydroquinone, t-butylphenol, catechol, and di-t-butylhydroxytoluene. Specific examples of the hydrocarbon compound include cyclohexadiene and diphenylmethane. The amount of the catalyst used (number of moles) is preferably less than the amount of use of the polymerization initiating compound (number of moles). When the amount of the catalyst used (number of moles) is too large, the polymerization is excessively controlled, and it may be difficult for the polymerization to proceed.

  Moreover, it is preferable that the temperature (polymerization temperature) in the case of living radical polymerization shall be 30-100 degreeC. If the polymerization temperature is too high, iodine at the polymerization terminal is decomposed, and the terminal is not stable, and living polymerization may not be performed, which is not preferable. In this polymerization method, it is preferable that iodine is bonded to the terminal, and the iodine is dissociated as a radical to generate a radical so that the terminal is stable. Here, when the monomer is an acrylate or vinyl type, the terminal is a secondary iodide, which is relatively stable and does not come off as an iodine radical, the polymerization may not proceed, or the distribution may be widened. . Although it is possible to dissociate by raising the temperature for this problem, it is preferable to perform moderate polymerization in the above temperature range from the viewpoint of environment and energy. Therefore, a tertiary iodide which is easy to generate radicals and is relatively stable is preferred, and the living radical polymerization used in the present invention is suitable for polymerization of methacrylate monomers. Useful.

  In the polymerization step, a polymerization initiator that can generate radicals is usually added. As the polymerization initiator, conventionally known azo initiators and peroxide initiators are used. It is preferable to use a polymerization initiator that generates radicals sufficiently within the above polymerization temperature range. Specifically, it is preferable to use an azo initiator such as 2,2'-azobis (4-methoxy-2,4-dimethylvaleronitrile). The amount of the polymerization initiator used is preferably 0.001 to 0.1 mol times, more preferably 0.002 to 0.05 mol times with respect to the monomer. If the amount of the polymerization initiator used is too small, the polymerization reaction may not proceed sufficiently. On the other hand, if the amount of the polymerization initiator used is too large, a normal radical polymerization reaction that is not a living radical polymerization reaction may proceed as a side reaction.

  The living radical polymerization may be bulk polymerization without using an organic solvent, but is preferably solution polymerization using the organic solvent described above. The used organic solvent can be used as a solvent for the pigment dispersion as it is. The organic solvent is preferably one that can dissolve components such as a polymerization initiator compound, a catalyst, a monomer component, and a polymerization initiator.

  In addition, the organic solvent used in these polymerizations can be used as it is as a solution of the AB block copolymer, but if necessary, the polymer can be taken out of the solution and solidified. The method for taking out the polymer is not particularly limited. For example, the polymer may be precipitated as a poor solvent and filtered or dried, or the solution may be dried to take out only the polymer to obtain a solid polymer. The obtained solid polymer may be used as it is as the polymer solution of the present invention.

  In the case of solution polymerization, the solid content concentration (monomer concentration) of the polymerization solution is preferably 5 to 80% by mass, more preferably 20 to 60% by mass. If the solid content concentration of the polymerization solution is less than 5% by mass, the monomer concentration is too low and the polymerization may not be completed. On the other hand, when the solid content concentration of the polymerization liquid exceeds 80% by mass or bulk polymerization, the viscosity of the polymerization liquid becomes too high, and stirring tends to be difficult and the polymerization yield tends to decrease. Living radical polymerization is preferably carried out until the monomer runs out. Specifically, the polymerization time is preferably 0.5 to 48 hours, more preferably 1 to 24 hours. The polymerization atmosphere is not particularly limited, and may be an atmosphere in which oxygen exists within a normal range or a nitrogen stream atmosphere. Moreover, the material (monomer etc.) used for superposition | polymerization may use what removed the impurity by distillation, activated carbon treatment, an alumina treatment, etc., and may use a commercial item as it is. Furthermore, polymerization may be performed under light shielding, or polymerization may be performed in a transparent container such as glass.

The AB block copolymer obtained by the above-described polymerization method is formed by controlling the molecular weight of the main chain by adjusting the use balance of the methacrylate-based monomers and the polymerization initiating compound at the time of living radical polymerization. Become a thing. Specifically, a polymer whose main chain has an arbitrary molecular weight can be obtained by appropriately setting the number of moles of the monomer with respect to the number of moles of the polymerization initiating compound. For example, when 1 mol of a polymerization initiating compound is used and 500 mol of a monomer having a molecular weight of 100 is used for polymerization, a polymer having a theoretical molecular weight of “1 × 100 × 500 = 50000” can be obtained. That is, the theoretical molecular weight of the main chain polymer can be calculated by the following formula (1). The above “molecular weight” is a concept including both the number average molecular weight (Mn) and the weight average molecular weight (Mw).
“Theoretical molecular weight of main chain polymer” = “1 mol of polymerization initiation compound” × “monomer molecular weight” × “number of moles of monomer / number of moles of polymerization initiation compound” (1)
The amount of the polymerization initiating compound is as described above.

  In the polymerization step, there may be a case where a bimolecular termination or a disproportionation side reaction is involved, so that a main chain polymer having the above theoretical molecular weight may not be obtained. It is preferable that these are obtained without causing side reactions. The polymerization rate may not be 100%. Furthermore, once the polymerization is completed, the polymerization may be completed by adding a polymerization initiating compound or a catalyst and consuming the remaining monomer. That is, the pigment dispersant that characterizes the present invention may contain an AB block copolymer having the above-mentioned structure having a specific main chain, which is produced as described above, by the production method as described above. That's fine.

  As described above, the pigment dispersion of the present invention is more effective when a hardly decomposable pigment is used as the pigment. Examples of the hardly decomposable pigment include organic pigments having a carbonyl group and an amino group independently in the cyclic structure in the molecule, or these groups bonded to each other as an amide group, a ureido group, or an imide group. Among these, remarkable effects are obtained particularly when diketopyrrolopyrrole pigments, quinophthalone pigments, and anthraquinone pigments are used. Although these pigments are pigments for color filters that require fine dispersion, high transparency, and high contrast, they are difficult to finely disperse with conventional pigment dispersants. A pigment dispersion in which a pigment is finely dispersed is extremely useful and is expected to be used as a colorant for a color filter.

  When the pigment dispersion of the present invention is used, for example, as a colorant for a color filter as described above, a suitable organic solvent used in combination is a propylene glycol solvent from the viewpoint of safety and environment. Among these, propylene glycol monomethyl ether acetate (dielectric constant 8.3) is particularly preferable. This solvent is an aprotic polar solvent desired in the present invention and meets the requirements of a low dielectric constant, and is higher by using a solvent system having such characteristics in the pigment dispersion of the present invention. In addition, fine pigment dispersibility, high storage stability, and low viscosity are obtained, and the superior effects of the present invention are realized.

[Pigment dispersion]
The present invention achieves the provision of a pigment dispersion that provides an excellent effect by using the above AB block copolymer as a pigment dispersant. The pigment dispersion of the present invention comprises a pigment, a pigment dispersant, and an organic solvent, and the blending ratio thereof is 5 to 20% by mass for the pigment, 0.5 to 30% by mass for the pigment dispersant, The organic solvent mass is preferably in the range of 50 to 94.5%. The pigment content is 0.5 to 20% by mass, more preferably 10 to 18% by mass. If it is less than 0.5%, the performance as a colorant is insufficient and the color is light, and if it exceeds 20% by mass, the viscosity may be too high. The pigment dispersant is used in the range of 0.5 to 30% by mass. The pigment dispersant is preferably used within a range of 10 to 150 parts by mass with respect to 100 parts by mass of the pigment. If the amount is less than 10 parts, the storage stability of the pigment may be insufficient. If the amount is more than 150 parts, the dispersant becomes excessive and the viscosity may increase, which is not preferable. The above is the amount of the dispersant relative to the pigment in the pigment dispersion of the present invention, and may be used in the pigment dispersion at the above ratio. The rest is an organic solvent.

  Moreover, you may add another additive to the pigment dispersion liquid of this invention. Examples of the additive include a leveling agent, an ultraviolet absorber, an antifoaming agent, an antiseptic, an antibacterial agent, a dye, a surfactant, and a viscosity modifier. In addition, a binder component for forming a film or developing alkali during color filter production may be added, and a polymer structure such as polyacrylate (acrylic resin), polystyrene acrylate, polyolefin, polyester, polyurethane, There is no particular limitation. The amount thereof is also arbitrary and is not particularly limited, but is preferably 10 to 200 parts by mass, more preferably 20 to 150 parts by mass with respect to 100 parts by mass of the pigment.

  The pigment dispersion of the present invention can be obtained by dispersing a pigment, a pigment dispersant, an organic solvent and, if necessary, an additive used by a conventionally known method, and the method is not particularly limited. Examples of the disperser used at that time include a kneader such as a kneader, a two-roll, a three-roll, and a miracle KCK (Asada Steel Corporation, trade name), an ultrasonic disperser, a high-pressure homogenizer, Fluidizer (Mizuho Industry Co., Ltd., trade name), Nanomizer (Yoshida Kikai Kogyo Co., Ltd., trade name), Starburst (Sugino Machine Co., Ltd., trade name), G-Smasher (Rix Corporation, trade name), etc. Can be mentioned. In the case of using a bead medium such as glass or zircon, a ball mill, a sand mill, a horizontal media mill disperser, a colloid mill, or the like can be used. The dispersion method is not particularly limited.

  In the present invention, in order to obtain a pigment dispersion having a desired particle size and distribution, the size of the grinding media of the disperser is reduced, the filling rate of the grinding media is increased, and the processing time is increased. It is possible to use a method such as slowing down, and classifying with a filter or centrifuge after pulverization. Or the combination of those methods is mentioned. Next, the obtained pigment dispersion may be used as it is, but it is preferable to remove coarse particles by centrifuging or passing through an arbitrary filter. As described above, the pigment dispersion of the present invention can be obtained.

  Regarding the physical properties of the resulting pigment dispersion of the present invention, the physical properties such as viscosity are not particularly limited and are arbitrary. The viscosity range is 1 to 100 mPa · s, preferably 3 to 20 mPa · s, but is not limited at all because it varies depending on the desired pigment concentration and application. Other physical properties are not particularly limited.

[Resin-treated pigment]
In the present invention, in order to obtain a higher degree of stability by using the AB block copolymer that characterizes the present invention, a method of depositing and encapsulating a dispersant on the pigment surface is used to obtain a resin-treated pigment. Is also a preferred embodiment. In other words, the pigment is treated with the AB block copolymer that characterizes the present invention in advance, so that the pigment and the pigment dispersant are brought into contact and intimately adhering to each other, thereby strongly adsorbing by hydrogen bonding, thereby achieving higher fine dispersion, higher Dispersion stability can be obtained. Conventionally, a finer pigment is used after being dried and pulverized. In this drying, the finely divided pigment itself comes into contact and is dried and agglomerated to form a secondary aggregate having a large particle size, and a great deal of energy is required to disperse the finely divided pigment. In that respect, pre-treatment with a resin prevents the resin from agglomerating due to contact of the pigment particles themselves, prevents secondary aggregation, and can be more easily dispersed into a finer pigment particle diameter. .

  The composition of the resin-treated pigment is such that the AB block copolymer is 10 to 150 parts by weight with respect to 100 parts by weight of the pigment so that the ratio of the pigment to the pigment dispersant is suitable for the pigment dispersion of the present invention. Within the range of parts by mass. As described above, when the amount is less than 10 parts by mass, the storage stability of the pigment may be insufficient. When the amount is more than 150 parts by mass, the dispersant may become excessive and the viscosity may increase.

  A conventionally known method can be used as a method for producing the resin-treated pigment, and is not particularly limited. For example, a method of treating a pigment by precipitating a polymer for treatment by phase transition or pH conversion, or adding a polymer or a solution thereof when kneading the pigment and kneading together to refine and coat the pigment. There is a method in which the pigment is treated with a resin by carrying out at the same time, followed by precipitation in a poor solvent or neutralization.

  More specifically, the following methods can be used. For example, a pigment, preferably a pigment paste, may be peptized with water, and a polymerization solution may be added to treat the pigment while precipitating the AB block copolymer characterizing the present invention. If the AB block copolymer has a functional group, the AB block copolymer is neutralized and ionized to form an aqueous solution of the AB block copolymer, added, stirred, mixed, or dispersed, and then returned to neutral pH. A method of treating the pigment by insolubilizing and precipitating the -B block copolymer, adding an A-B block copolymer, preferably an insoluble organic solvent dissolved in an organic solvent to the pigment water slurry, In the method for uniting the AB block copolymer dissolved in the organic solvent and the finer step of the pigment, when the water-soluble inorganic salt is ground together with the medium, water and the organic solvent, the AB block copolymer Over, the organic solvent solution or added to neutralized solution, triturated, after attrition, and a method of surface treatment or return the pH or water deposit. Furthermore, the pigment-dispersed liquid of the present invention can be obtained by dispersing the resin-treated pigment obtained as described above in the above-described organic solvent by the above-described conventionally known method. By comprising in this way, the effect that a pigment can be finely dispersed more easily is acquired.

  The pigment dispersion of the present invention can be used as a colorant for various articles. For example, it can be used as a pigment colorant composition such as paint, gravure ink, offset ink, inkjet ink, coating agent, stationery color and the like. In particular, it is possible to reduce the viscosity and increase the fineness of the pigment, and since it has good long-term storage stability, it is suitable for use as a color filter colorant, a UV curable inkjet ink colorant, and an oil-based inkjet ink colorant. Is preferred.

  EXAMPLES Next, although an 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 unless otherwise specified.

[Synthesis Example 1: Synthesis of acidic resin solution UP-1 used in Examples]
First, the following was charged in a reactor of a 1 liter separable flask equipped with a stirrer, a reverse flow condenser, a thermometer, and a nitrogen introduction tube, and a block copolymer of A was synthesized as follows. Specifically, in the above reactor, 380.2 parts of propylene glycol monomethyl ether acetate (hereinafter abbreviated as PGMAc) as an organic solvent and 2.0 parts of iodine for obtaining an iodine compound as a polymerization initiating compound were used. , 2,2′-azobis (4-methoxy-2,4-dimethylvaleronitrile) (hereinafter abbreviated as V-70), and 7.4 parts of diphenylmethane (hereinafter abbreviated as DPM) as a catalyst Further, 40.1 parts of methyl methacrylate (hereinafter abbreviated as MMA) and 56.9 parts of butyl methacrylate (hereinafter abbreviated as BMA) were charged and stirred, and heated to 45 ° C. After 2 hours, the brown color of iodine disappeared, and during this time, it was confirmed that the polymerization initiator V-70 reacted with iodine to become a polymerization initiator compound which was an iodine compound.

  Thereafter, polymerization was carried out for 3 hours while maintaining the above temperature, and a part of the reaction solution was sampled at this point. When the solid content of this sample was measured, it was 19.9%, and the polymerization rate calculated based on this was almost 100%. Hereinafter, the polymerization rate was calculated by the same method as described above. Further, when the molecular weight was measured by GPC using tetrahydrofuran (hereinafter abbreviated as THF) as a developing solvent, the number average molecular weight (hereinafter sometimes referred to as Mn) was 4600, and the degree of dispersion was 1.29. . Hereinafter, the number average molecular weight is a value measured by a differential refractive index detector of GPC using a THF solvent as a developing solvent. A polymer block solution of A constituting the block copolymer was obtained as described above.

  Next, after the temperature of the polymer block solution of A obtained above was lowered to 40 ° C., 17.2 parts of methacrylic acid (hereinafter abbreviated as MAA), 89.3 parts of MMA, 2- (2-oxoimidazolidine- 59.4 parts of 3-yl) ethyl methacrylate (hereinafter abbreviated as OEMA) and 4.5 parts of V-70 were added, and the mixture was further polymerized at 40 ° C. for 4 hours to form a B polymer block. The acid value in the B chain is calculated to be 67.6 mgKOH / g.

The acid value in the B chain was calculated as follows. First, the amount of MAA per part of B chain composition is determined as follows.
17.2 / (17.2 + 89.3 + 59.4) = 0.137 parts Next, when the molecular weight of MAA is 86.1 and the molecular weight of KOH is 56.1, the acid value of the B chain is determined as follows: Calculated. Hereinafter, the acid value in the B chain was calculated by the same method.
(0.1037 / 86.1) × 56.1 × 1000 = 67.6 mgKOH / g

  This polymer solution had a solid content of 40.0%, and it was confirmed that the polymerization rate was almost 100%. Moreover, Mn was 13400, dispersion degree was 1.48, and peak top molecular weight was 19800. Since it was confirmed that the molecular weight was shifted to the higher molecular weight side than when the polymer block of A was formed, it is considered that the AB block copolymer was formed. The number average molecular weight of the B polymer block can be calculated as a value obtained by subtracting the A polymer block from the molecular weight of the AB block copolymer. From this, the number average molecular weight of the B polymer block is calculated as 8800. It was done.

  Furthermore, after the sample was diluted with toluene and ethanol, the acid value of the entire AB block copolymer was measured by acid-base titration using a phenolphthalein solution as an indicator and a 0.1% ethanolic potassium hydroxide solution. Was determined, and the measured acid value was 42.2 mgKOH / g. Hereinafter, the actually measured acid value is a value calculated by performing the same operation as described above.

  Next, the reaction solution obtained above was transferred to a 2 L beaker, 394.3 parts of PGMAc was added so that the solid content was 25%, and the mixture was stirred until uniform. The solid content of this liquid was measured and found to be 24.9%. This resin solution is referred to as UP-1.

[Synthesis Example 2: Synthesis of acidic resin solution UP-2 used in Examples]
An AB block copolymer was synthesized in the same manner as in Synthesis Example 1 using the same apparatus as in Synthesis Example 1 and using the following materials to obtain a resin solution of a pigment dispersant. Specifically, in the same apparatus as in Synthesis Example 1, 405.3 parts of PGMAc as a solvent, 2.0 parts of iodine for obtaining an iodine compound as a polymerization initiating compound, and 7.4 of V-70 are obtained. Part, DPM 0.3 parts, MMA 40.1 parts, BMA 56.9 parts and MAA 8.6 parts were stirred and heated to 45 ° C. Polymerization was carried out for 5 hours while maintaining the above temperature, and a part of the reaction solution was sampled at this point. The solid content of this sample was measured and found to be 20.2%, and the polymerization rate calculated based on this was almost 100%. Moreover, when molecular weight was measured, Mn was 4500 and dispersion degree was 1.36. As described above, a polymer block solution of A was obtained.

  Subsequently, after the temperature of the polymer block solution of A obtained above was lowered to 40 ° C., 1- [2- (methacryloyloxy) ethyl] phthalate (hereinafter abbreviated as PA), which is a phthalic acid half ester type methacrylate, was 55 7 parts, 79.2 parts of MMA, 39.6 parts of OEMA, and 5.2 parts of V-70 were added, followed by polymerization at 40 ° C. for 4 hours to form a polymer block of B. The acid value in the B chain was calculated to be 64.3 mgKOH / g.

  This polymer solution had a solid content of 40.4%, and it was confirmed that the polymerization rate was almost 100%. Moreover, Mn was 10400, dispersion degree was 1.47, and peak top molecular weight was 15300. The number average molecular weight of the polymer block of B was calculated to be 5900. The actually measured acid value was 42.5 mgKOH / g.

  Next, the reaction solution obtained above was transferred to a 2 L beaker, 420.1 parts of PGMAc was added so that the solid content was 25%, and the mixture was stirred until it became uniform. The solid content of this liquid was measured and found to be 24.8%. This resin solution is referred to as UP-2.

[Synthesis Example 3: Synthesis of acidic resin solution UP-3 used in Examples]
An AB block copolymer was synthesized in the same manner as in Synthesis Example 1 using the same apparatus as in Synthesis Example 1 and using the following materials to obtain a resin solution of a pigment dispersant. Specifically, to obtain 385.4 parts of PGMAc as a solvent and an iodine compound as a polymerization initiating compound in the same apparatus as in Synthesis Example 1, 2.0 parts of iodine and 7.4 parts of V-70 , DPM (0.3 parts), MMA (40.1 parts), BMA (56.9 parts), and MAA (8.6 parts) were charged and stirred and heated to 45 ° C. Polymerization was carried out for 5 hours while maintaining the above temperature, and a part of the reaction solution was sampled at this point. The solid content of this sample was measured and found to be 21.0%, and the polymerization rate calculated based on this was almost 100%. Moreover, when molecular weight was measured, Mn was 4400 and dispersion degree was 1.32. As described above, a polymer block solution of A constituting the block copolymer of A was obtained.

  Next, after the temperature of the polymer block solution of A obtained above was lowered to 40 ° C., 42.0 parts of 2- (methacryloyloxy) ethyl phosphate (hereinafter abbreviated as P1M), which is a phosphoric acid half ester type methacrylate, 79.2 parts of MMA, 39.6 parts of OEMA, and 4.5 parts of V-70 were added, and polymerization was further performed at 40 ° C. for 4 hours to form a polymer block of B. The acid value in the B chain was calculated to be 139.4 mg KOH / g.

  This polymer solution had a solid content of 40.3% and was confirmed to have a polymerization rate of almost 100%. Further, Mn was 9900, dispersity was 1.51, and peak top molecular weight was 15100. The number average molecular weight of the polymer block of B was calculated to be 4500. The actually measured acid value was 86.3 mgKOH / g.

  Next, the reaction solution obtained above was transferred to a 2 L beaker, 404.1 parts of PGMAc was added so that the solid content was 25%, and the mixture was stirred until uniform. The solid content of this liquid was measured and found to be 25.2%. This resin solution is referred to as UP-3.

Table 1 shows the physical properties of the resin solutions of the present invention used as dispersants for the pigment dispersions of Examples obtained in Synthesis Examples 1 to 3 above.

[Comparative Synthesis Example 1: Synthesis of acidic resin solution RUP-1 by random polymerization]
Using the same apparatus as in Synthesis Example 1, 365.8 parts of PGMAc was added as a solvent and heated to 70 ° C. 119.6 parts of MMA prepared by dissolving 10 parts of 2,2′-azobis (2,4-dimethylvaleronitrile) (hereinafter abbreviated as V-65) prepared in a separate container in advance, and BMA A monomer solution containing 85.3 parts, 25.8 parts MAA, and 19.8 parts OEMA was added dropwise to the above reactor over 1.5 hours. After completion of the dropping, polymerization was further performed at the same temperature for 5 hours to obtain a polymer solution. The obtained polymer solution had a solid content of 40.1%. The polymer had a Mn of 9600, a dispersity of 1.98, and an actually measured acid value of 66.9 mgKOH / g. This resin solution is referred to as RUP-1. This is the same composition as the resin obtained in Synthesis Example 1, but is a random copolymer having a random structure and constitutes a comparative example. The composition and physical properties are summarized in Table 2.

[Comparative Synthesis Example 2: Synthesis of acidic resin solution RUP-2 having a hydroxyl group in the B chain]
An AB block copolymer was synthesized using the same apparatus as in Synthesis Example 1 and using the following materials in the same manner as in Synthesis Example 1. In this example, the monomer unit is a cyclic ureido methacrylate. OEMA was not used. Specifically, in order to obtain 372.0 parts of PGMAc and an iodine compound as a polymerization initiating compound in the same apparatus as used in Synthesis Example 1, 2.0 parts of iodine and 7.4 of V-70 are obtained. Parts, DPM 0.3 parts, MMA 60.1 parts and BMA 85.3 parts were charged and stirred and heated to 45 ° C. Polymerization was carried out for 5 hours while maintaining the above temperature, and a part of the reaction solution was sampled at this point. The solid content of this sample was measured and found to be 27.5%, and the polymerization rate calculated based on this was almost 100%. Moreover, when molecular weight was measured, Mn was 6600 and dispersion degree was 1.28. As described above, a polymer block solution of A was obtained.

  Next, the temperature of the polymer block solution of A obtained above was lowered to 40 ° C., then 25.8 parts of MAA, 59.5 parts of MMA, and 26.0 parts of 2-hydroxyethyl methacrylate (hereinafter abbreviated as HEMA). And 3.3 parts of V-70 were added, and further polymerized at 40 ° C. for 4 hours to form a polymer block of B. The acid value in the B chain was calculated to be 151.0 mgKOH / g.

  This polymer solution had a solid content of 39.9%, and it was confirmed that the polymerization rate was almost 100%. Further, Mn was 12500, the degree of dispersion was 1.45, and the peak top molecular weight was 17900. The number average molecular weight of the polymer block of B was calculated to be 5900. The actually measured acid value was 65.8 mgKOH / g.

  Next, the reaction solution obtained above was transferred to a 2 L beaker, 385.1 parts of PGMAc was added so that the solid content was 25%, and the mixture was stirred until uniform. The solid content of this liquid was measured and found to be 25.3%. This resin solution is referred to as RUP-2. This is because, in Synthesis Example 1, in the synthesis of the polymer block of B, a hydroxyl group capable of hydrogen bonding to the pigment surface by using HEMA instead of introducing a cyclic ureido group using OEMA as a monomer unit. Is a block copolymer into which is introduced.

[Comparative Synthesis Example 3: Synthesis of acidic resin solution RUP-3 having no group necessary for hydrogen bonding in B chain]
An AB block copolymer was synthesized in the same manner as in Synthesis Example 1 using the same apparatus as in Synthesis Example 1 and using the following materials. In this example, OEMA and HEMA were used as monomer units. I didn't. Specifically, in the same apparatus as used in Synthesis Example 1, 363.2 parts of PGMAc and 2.0 parts of iodine and 7.4 of V-70 are obtained to obtain iodine compound as a polymerization initiating compound. Parts, DPM 0.3 parts, MMA 60.1 parts and BMA 85.3 parts were charged and stirred and heated to 45 ° C. Polymerization was carried out for 5 hours while maintaining the above temperature, and a part of the reaction solution was sampled at this point. The solid content of this sample was measured and found to be 27.9%, and the polymerization rate calculated based on this was almost 100%. Further, when the molecular weight was measured, the number average molecular weight was 6700, and the degree of dispersion was 1.27. As described above, a polymer block solution of A was obtained.

  Next, after the temperature of the polymer block solution of A obtained above was lowered to 40 ° C., 25.8 parts of MAA, 79.5 parts of MMA, and 3.2 parts of V-70 were added, and further 4 ° C. at 40 ° C. Polymerization was performed for a time to form a polymer block of B. The acid value in the B chain was calculated to be 159.6 mgKOH / g.

  This polymer solution had a solid content of 40.2%, and it was confirmed that the polymerization rate was almost 100%. Further, Mn was 11,500, the degree of dispersion was 1.41, and the peak top molecular weight was 16,200. The number average molecular weight of the polymer block of B was calculated to be 4800. The actually measured acid value was 67.2 mgKOH / g.

  Subsequently, the reaction solution obtained above was transferred to a 2 L beaker, 376 parts of PGMAc was added so that the solid content was 25%, and the mixture was stirred until uniform. The solid content of this liquid was measured and found to be 25.1%. This resin solution is referred to as RUP-3. This stipulates that a cyclic ureido group capable of hydrogen bonding is introduced into the polymer block of B in order to adsorb on the pigment surface, whereas the cyclic ureido group necessary for hydrogen bonding is also a hydroxyl group. It is a block copolymer that has not been introduced.

Table 3 shows the physical properties of the resin solutions obtained in Comparative Synthesis Examples 2 and 3 and used as the dispersant for the pigment dispersion liquid of Comparative Example.

[Synthesis Example 4: Synthesis of basic resin solution UP-4 used in Examples]
An AB block copolymer was synthesized using the same apparatus as in Synthesis Example 1 and the following materials were used in the same manner as in Synthesis Example 1 to obtain a resin solution. Specifically, in order to obtain 343.1 parts of PGMAc as a solvent and an iodine compound as a polymerization initiating compound in the same apparatus as in Synthesis Example 1, 2.0 parts of iodine and 7.4 parts of V-70 , DPM (0.3 parts), MMA (40.1 parts) and BMA (56.9 parts) were charged and stirred and heated to 45 ° C. Polymerization was carried out for 5 hours while maintaining the above temperature, and a part of the reaction solution was sampled at this point. The solid content of this sample was measured and found to be 21.5%, and the polymerization rate calculated based on this was almost 100%. Moreover, when molecular weight was measured, Mn was 4500 and dispersion degree was 1.26. As described above, a polymer block solution of A was obtained.

  Next, after the temperature of the polymer block solution of A obtained above was lowered to 40 ° C., 31.3 parts of N, N-dimethylaminoethyl methacrylate (hereinafter abbreviated as DMAEMA), 89.3 parts of MMA, and OEMA 19.8 parts and 3.3 parts of V-70 were added, and further polymerized at 40 ° C. for 4 hours to form a polymer block of B. The amine value in the B chain is calculated to be 101.1 mgKOH / g.

The amine value in the B chain was calculated as follows.
First, the amount of DMAEMA per part of B chain composition is determined.
31.3 / (31.3 + 59.5 + 19.8) = 0.2830 parts Next, when the molecular weight of DMAEMA is 157.1 and the molecular weight of KOH is 56.1, the acid value of the B chain is as follows: Calculated. Hereinafter, the amine value in the B chain is a value calculated by the same method.
(0.2830 / 157.1) × 56.1 × 1000 = 101.1 mgKOH / g

  This polymer solution had a solid content of 40.0%, and it was confirmed that the polymerization rate was almost 100%. Moreover, Mn was 9800, dispersion degree was 1.46, and peak top molecular weight was 14200. The number average molecular weight of the polymer block of B was calculated to be 5300. Further, the sample was diluted with toluene and ethanol, and then the entire AB block copolymer was measured with a potentiometric titrator (AT-510, manufactured by Kyoto Electronics Industry Co., Ltd.) using a 0.1N 2-propanolic hydrochloric acid solution. When the actually measured amine value was determined, the amine value was 47.3 mgKOH / g. Hereinafter, the actually measured amine value is a value calculated by performing the same operation as described above.

  Next, the reaction solution obtained above was transferred to a 2 L beaker, 356.1 parts of PGMAc was added so that the solid content was 25%, and the mixture was stirred until uniform. The solid content of this liquid was measured and found to be 25.2%. This resin solution is referred to as UP-4.

[Synthesis Example 5: Synthesis of basic resin solution UP-5 used in Examples]
An AB block copolymer was synthesized using the same apparatus as in Synthesis Example 1 and the following materials were used in the same manner as in Synthesis Example 1 to obtain a resin solution. Specifically, in the same apparatus as in Synthesis Example 1, 333.7 parts of PGMAc as a solvent, 2.0 parts of iodine for obtaining an iodine compound as a polymerization initiating compound, and 7.4 of V-70 are obtained. Parts, DPM 0.3 parts, MMA 40.1 parts and BMA 56.9 parts were charged and stirred and heated to 45 ° C. Polymerization was carried out for 5 hours while maintaining the above temperature, and a part of the reaction solution was sampled at this point. When the solid content of this sample was measured, it was 22.0%, and the polymerization rate calculated based on this was almost 100%. Moreover, when molecular weight was measured, Mn was 4500 and dispersion degree was 1.28. As described above, a polymer block solution of A was obtained.

  Next, after the temperature of the polymer block solution of A obtained above was lowered to 40 ° C., 15.7 parts of DMAEMA, 59.5 parts of MMA, 59.4 parts of OEMA, and 4.0 parts of V-70 were added. Further, polymerization was carried out at 40 ° C. for 4 hours to form a polymer block of B. The amine value in the B chain is calculated to be 41.6 mgKOH / g.

  This polymer solution had a solid content of 40.0%, and it was confirmed that the polymerization rate was almost 100%. Further, Mn was 13,600, the degree of dispersion was 1.48, and the peak top molecular weight was 20,200. The molecular weight of the polymer block of B was calculated to be 9100. The measured amine value was 24.4 mgKOH / g.

  Next, the reaction solution obtained above was transferred to a 2 L beaker, 347.4 parts of PGMAc was added so that the solid content was 25%, and the mixture was stirred until uniform. The solid content of this liquid was measured and found to be 25.1%. This resin solution is referred to as UP-5.

[Synthesis Example 6: Synthesis of basic resin solution UP-6 used in Examples]
Using the same apparatus as in Synthesis Example 1, an AB block copolymer as a pigment dispersant was synthesized in the same manner as in Synthesis Example 1, and a resin solution was obtained. Specifically, in order to obtain 375.4 parts of PGMAc as a solvent and an iodine compound as a polymerization initiating compound in the same apparatus as in Synthesis Example 1, 2.0 parts of iodine and 7.4 parts of V-70 , DPM (0.3 parts), MMA (40.1 parts) and BMA (113.8 parts) were charged and stirred and heated to 45 ° C. Polymerization was carried out for 5 hours while maintaining the above temperature, and a part of the reaction solution was sampled at this point. The solid content of this sample was measured and found to be 28.5%, and the polymerization rate calculated based on this was almost 100%. Moreover, when molecular weight was measured, Mn was 7200 and dispersion degree was 1.32. As described above, a polymer block solution of A was obtained.

  Next, after the temperature of the polymer block solution of A obtained above was lowered to 40 ° C., 15.7 parts of DMAEMA, 59.5 parts of MMA, 29.7 parts of OEMA, and 3.1 parts of V-70 were added. Further, polymerization was carried out at 40 ° C. for 4 hours to form a polymer block of B. The amine value in the B chain was calculated to be 53.6 mgKOH / g.

  This polymer solution had a solid content of 40.0%, and it was confirmed that the polymerization rate was almost 100%. Further, Mn was 11,300, the degree of dispersion was 1.48, and the peak top molecular weight was 16,800. The number average molecular weight of the polymer block of B was calculated to be 4100. The actually measured amine value was 21.4 mgKOH / g.

  Next, the reaction solution obtained above was transferred to a 2 L beaker, 388.2 parts of PGMAc was added so that the solid content was 25%, and the mixture was stirred until it became uniform. The solid content of this liquid was measured and found to be 25.0%. This resin solution is referred to as UP-6.

Table 4 shows the composition and physical properties of the resin solutions used in the pigment dispersion liquids of Examples obtained in Synthesis Examples 4 to 6 above.

[Comparative Synthesis Example 4: Synthesis of basic resin solution RUP-4 by random polymerization]
Using the same apparatus as in Synthesis Example 1, 371.1 parts of PGMAc was added as a solvent and heated to 70 ° C. In this, 129.4 parts of MMA in which 10 parts of V-65 were dissolved, 56.9 parts of BMA, 31.3 parts of DMAEMA, and 19.8 parts of OEMA, which were prepared in a separate container in advance, were contained. The monomer solution to be added was dropped into the above reactor over 1.5 hours. After completion of the dropping, polymerization was further performed at the same temperature for 5 hours to obtain a polymer solution. The resulting polymer solution had a solid content of 40.0%. The polymer had an Mn of 9400, a dispersity of 1.99, and an actually measured amine value of 47.0 mgKOH / g. This resin solution is referred to as RUP-4. This is the same composition as the resin obtained in Synthesis Example 4, but is a random polymer having a random structure, and constitutes a comparative example. The composition and physical properties of the obtained random polymer are summarized in Table 2.

[Comparative Synthesis Example 5: Synthesis of basic resin solution RUP-5 having hydroxyl group in B chain]
An AB block copolymer was synthesized using the same apparatus as in Synthesis Example 1 and using the following materials in the same manner as in Synthesis Example 1. In this example, the monomer unit is a cyclic ureido methacrylate. OEMA was not used. Specifically, in order to obtain 307.7 parts of PGMAc and an iodine compound as a polymerization initiating compound in the same apparatus as used in Synthesis Example 1, 2.0 parts of iodine and 7.4 of V-70 are obtained. Parts, DPM 0.3 parts, MMA 40.1 parts and BMA 56.9 parts were charged and stirred and heated to 45 ° C. Polymerization was performed for 3 hours while maintaining the above temperature, and a part of the reaction solution was sampled at this point. The solid content of this sample was measured and found to be 23.4%, and the polymerization rate calculated based on this was almost 100%. Moreover, when molecular weight was measured, Mn was 4600 and dispersion degree was 1.28. As described above, a polymer block solution of A was obtained.

  Next, after the temperature of the polymer block solution of A obtained above was lowered to 40 ° C., 31.3 parts of DMAEMA, 59.5 parts of MMA, 26.0 parts of HEMA, and 3.3 parts of V-70 were added. Further, polymerization was carried out at 40 ° C. for 4 hours to form a polymer block of B. The amine value in the B chain was calculated to be 95.7 mgKOH / g.

  This polymer solution had a solid content of 40.2%, and it was confirmed that the polymerization rate was almost 100%. Moreover, Mn was 10700, dispersion degree was 1.44, and peak top molecular weight was 18200. The number average molecular weight of the polymer block of B was calculated to be 6100. The actually measured amine value was 43.4 mgKOH / g.

  Next, the reaction solution obtained above was transferred to a 2 L beaker, 320.7 parts of PGMAc was added so that the solid content was 25%, and the mixture was stirred until uniform. The solid content of this liquid was measured and found to be 25.1%. This resin solution is referred to as RUP-5. This is a block copolymer in which, in the polymer blocks of B synthesized in Synthesis Examples 4 to 6, instead of introducing a cyclic ureido group by using OEMA as a monomer unit, a hydrogen-bonded hydroxyl group is introduced.

[Comparative Synthesis Example 6: Synthesis of basic resin solution RUP-6 having no group necessary for hydrogen bonding in B chain]
An AB block copolymer was synthesized in the same manner as in Synthesis Example 1 using the same apparatus as in Synthesis Example 1 and using the following materials. In this example, OEMA and HEMA were used as monomer units. I didn't. Specifically, in order to obtain 298.7 parts of PGMAc and an iodine compound as a polymerization initiating compound in the same apparatus as used in Synthesis Example 1, 2.0 parts of iodine and 7.4 of V-70 are obtained. Parts, DPM 0.3 parts, MMA 40.1 parts and BMA 56.9 parts were charged and stirred and heated to 45 ° C. Polymerization was carried out for 5 hours while maintaining the above temperature, and a part of the reaction solution was sampled at this point. The solid content of this sample was measured and found to be 23.9%, and the polymerization rate calculated based on this was almost 100%. Moreover, when molecular weight was measured, Mn was 4700 and dispersion degree was 1.25. As described above, a polymer block solution of A was obtained.

  Next, after the temperature of the polymer block solution of A obtained above was lowered to 40 ° C., 31.3 parts of DMAEMA, 79.5 parts of MMA, and 3.3 parts of V-70 were added, and further 4 at 40 ° C. Polymerization was performed for a time to form a polymer block of B. The amine value in the B chain was calculated to be 100.9 mgKOH / g.

  This polymer solution had a solid content of 39.8%, and it was confirmed that the polymerization rate was almost 100%. Moreover, Mn was 10200, dispersion degree was 1.46, and peak top molecular weight was 14900. The number average molecular weight of the polymer block of B was calculated to be 5600. The measured amine value was 53.6 mgKOH / g.

  Next, the reaction solution obtained above was transferred to a 2 L beaker, 311.7 parts of PGMAc was added so that the solid content was 25%, and the mixture was stirred until uniform. The solid content of this liquid was measured and found to be 24.9%. This resin solution is referred to as RUP-6. This stipulates that the polymer block of B introduces a hydrogen-bondable cyclic ureido group for adsorbing to the pigment surface, whereas the resin solution RUP-6 has a hydrogen bond. It is a block copolymer in which neither a cyclic ureido group nor a hydroxyl group necessary for the above is introduced.

Table 6 shows the composition and physical properties of the resin solutions used in the pigment dispersion liquids of Comparative Examples obtained in Comparative Synthesis Examples 5 and 6 above.

[Synthesis Example 7: Synthesis of Neutral Resin Solution UP-7 Used in Examples]
An AB block copolymer was synthesized in the same manner as in Synthesis Example 1 using the same apparatus as in Synthesis Example 1 and using the following materials to obtain a resin solution of a pigment dispersant. In this synthesis example, 325.3 parts of dibasic acid diester (dimethyl malonate, dimethyl glutarate, dimethyl adipate, trade name: DBE, product name: DBE) is obtained as a solvent, and an iodine compound as a polymerization initiating compound is obtained. For this purpose, 2.0 parts of iodine, 7.4 parts of V-70, 0.3 parts of DPM, 40.1 parts of MMA and 56.9 parts of BMA were charged and stirred at 45 ° C. Warmed to. Polymerization was carried out for 5 hours while maintaining the above temperature, and a part of the reaction solution was sampled at this point. The solid content of this sample was measured and found to be 22.4%, and the polymerization rate calculated based on this was almost 100%. Moreover, when molecular weight was measured, Mn was 4500 and dispersion degree was 1.27. A block copolymer of A was obtained as described above.

  Next, 89.3 parts of MMA, 39.6 parts of OEMA, and 3.9 parts of V-70 were added to the polymer block solution of A obtained above, and further polymerized at 45 ° C. for 4 hours. A polymer block was formed. This polymer solution had a solid content of 40.1%, and it was confirmed that the polymerization rate was almost 100%. Moreover, Mn was 10200, dispersion degree was 1.43, and peak top molecular weight was 14500. The number average molecular weight of the polymer block of B was calculated to be 5700.

  Next, the reaction solution was transferred to a 2 L beaker, 338.8 parts of DBE was added so that the solid content was 25%, and the mixture was stirred until uniform. The solid content of this liquid was measured and found to be 25.4%. This resin solution is referred to as UP-7. UP-7 is a neutral block copolymer having no acidic group or basic group in the polymer block of B exhibiting adsorptivity to the pigment.

[Synthesis Example 8: Synthesis of acidic resin solution UP-8 used in Examples]
An AB block copolymer was synthesized in the same manner as in Synthesis Example 1 using the same apparatus as in Synthesis Example 1 and using the following materials to obtain a resin solution of a pigment dispersant. In this synthesis example, as a solvent, 363.8 parts of diethylene glycol methyl ether (DEGME), an iodine compound as a polymerization initiating compound, 7.4 parts of V-70, 0.3 parts of DPM, , 60.1 parts of MMA and 85.3 parts of BMA were charged and stirred and heated to 45 ° C. Polymerization was carried out for 5 hours while maintaining the above temperature, and a part of the reaction solution was sampled at this point. The solid content of this sample was measured and found to be 27.9%, and the polymerization rate calculated based on this was almost 100%. Moreover, when molecular weight was measured, Mn was 6500 and dispersion degree was 1.31. A block copolymer of A was obtained as described above.

  Next, after the temperature of the polymer block solution of A obtained above was lowered to 40 ° C., 25.8 parts of MAA, 59.5 parts of MMA, 19.8 parts of OEMA, and 3.2 parts of V-70 were added. Further, polymerization was carried out at 40 ° C. for 4 hours to form a polymer block of B. The acid value in the B chain was calculated to be 158.9 mgKOH / g.

  This polymer solution had a solid content of 40.1%, and it was confirmed that the polymerization rate was almost 100%. Further, Mn was 12,800, dispersity was 1.49, and peak top molecular weight was 19,100. The number average molecular weight of the polymer block of B was calculated to be 6300. The actually measured acid value was 67.2 mgKOH / g.

  Next, the reaction solution was transferred to a 2 L beaker, 374.8 parts of DEGME was added so that the solid content was 25%, and the mixture was stirred until uniform. The solid content of the liquid was measured and found to be 25.2%. This resin solution is referred to as UP-8.

  Table 7 shows the composition and physical properties of the resin solutions of the present invention used in the dispersants of the pigment dispersions of Examples obtained in Synthesis Examples 7 and 8.

<Application to pigment colorant composition>
(Examples 1-4, Comparative Examples 1-4: Pigment dispersion using an acidic resin solution)
(A) Pigment Refinement Treatment PR254, PR177, PY138, PB15-6, and PG-58 were prepared as color filter pigments and subjected to the following refinement treatment. 100 parts of pigment, 400 parts of sodium chloride, and 130 parts of diethylene glycol were charged into a kneader (a pressure kneader manufactured by Moriyama Co., Ltd.) equipped with a sealing lid used during pressurization. Premixed until a uniformly wet mass was formed in the kneader. The pressure lid was closed and kneaded and ground for 7 hours while pressing the contents at a pressure of 6 kg / cm ² to obtain a ground product. The obtained ground product was put into 3000 parts of 2% sulfuric acid and stirred for 1 hour. Then, after filtering and removing sodium chloride and diethylene glycol, it washed sufficiently with water, and then dried and pulverized to obtain a pigment powder. The average particle diameter of the obtained pigment powder was about 30 nm.

(B) Preparation of pigment dispersion-1
Each component shown in Table 8 containing each of the pigments subjected to the above-mentioned micronization treatment was blended in the amounts (parts) shown in Table 8, and stirred for 2 hours with a dissolver. After confirming that there was no pigment mass, the dispersion was processed using a horizontal media disperser to prepare a pigment dispersion. In Table 8, “Synergist 1” used the following formula (11), “Synergist 2” used the following formula (12), and “Synergist 3” used the compound shown by the following formula (13). All of these synergists (pigment derivatives) have a basic functional group. The “acrylic resin” in Table 8 has a monomer composition of BzMA / MAA = 80/20 (mass ratio), Mn of 5500 by GPC measurement, and PDI of 2.02 (solid content concentration is Measured with 30% PGMAc solution).

(C) Evaluation of pigment dispersion-1
The measurement result of the average particle diameter of the pigment contained in the pigment dispersion, the initial viscosity of the pigment dispersion, and the temperature of the pigment dispersion having the composition shown in Table 8 prepared above were left at 45 ° C. for 3 days. The measurement results of the later viscosity (viscosity after storage) are summarized in Table 9. The viscosity was measured using an E-type viscometer at 60 rpm and 25 ° C.

  As shown in Table 9, the average particle diameters of the pigments contained in the pigment colorant compositions (pigment dispersions) of Examples 1 to 4 are all about 35 nm, and the refined pigment is sufficiently fine. Turned out to be distributed. In addition, in all of the pigment dispersions of Examples 1 to 4, the initial viscosity was 10 mPa · s or less. Moreover, when the initial viscosity and the viscosity after storage are compared, it can be seen that the change in viscosity is extremely small. From the above results, it was revealed that the pigment dispersions of Examples 1 to 4 have sufficient dispersion stability.

  On the other hand, when compared with the pigment dispersion liquid of Example 1, the pigment dispersion liquid of Comparative Example 1 has a large average particle diameter of the pigment and is not sufficiently finely dispersed. Furthermore, the dispersion was not fluid and the viscosity could not be measured from the beginning. This is considered to be because the resin structure of the resin solution used as the dispersant in Comparative Example 1 was random, that is, the steric effect sufficient to stabilize the dispersion could not be exhibited, and thus the dispersion could not be achieved.

  As shown in Table 9, the pigment dispersions of Comparative Examples 2 and 3 showed good values similar to those of Examples 2 and 3 in both average particle diameter and initial viscosity, but the viscosity after storage increased. This is because the resin solution used for the dispersant did not have OEMA introduced into the polymer block of B, which is the adsorptive chain of the pigment, or HEMA was introduced instead of OEMA. The action is weak, and it is considered that the pigment aggregated over time.

  On the other hand, in the pigment dispersion liquid of Comparative Example 4 using a resin solution that does not use OEMA or HEMA as a monomer unit as a dispersant, both the average particle diameter and the initial viscosity showed good values as in Example 4. Example 4 and Comparative Example 4 are organic pigments in which the pigment to be dispersed has no carbonyl group, amino group, amide group, ureido group, or imide group in the cyclic structure in the molecule. Since it is an example using PB15-6, in such a system, when the dispersant of the Example containing OEMA is used for the polymer block of B which is a feature of the present invention, of course, the comparative example not containing It has been found that sufficient dispersibility can be obtained even when a dispersant is used.

(Application examples 1-3: Application to resists for color filters)
(A) Preparation of Color Filter Resist Ink Each component shown in Table 10 containing the pigment dispersions of Examples 1 to 3 was blended in the amounts (parts) shown in Table 10, and mixed well with a mixer to obtain a color. A pigment colorant composition (pigment ink) for a color filter of each color as a resist was obtained. The “photosensitive acrylic resin varnish” in Table 10 is a varnish containing an acrylic resin obtained by reacting glycidyl methacrylate with a BzMA / MAA copolymer. This acrylic resin had Mn of 6000, PDI of 2.38, and an acid value of 110 mgKOH / g. In Table 10, “TMPTA” represents trimethylolpropane triacrylate, “HEMPA” represents 2-hydroxyethyl-2-methylpropionic acid, and “DEAP” represents 2,2-diethoxyacetophenone.

(B) Evaluation of color filter resist ink A glass substrate treated with a silane coupling agent was set on a spin coater. The red pigment ink-1 of Application Example 1 was spin-coated on a glass substrate at 300 rpm for 5 seconds. After pre-baking at 80 ° C. for 10 minutes, exposure was performed with a light amount of 100 mJ / cm ² using an ultrahigh pressure mercury lamp to produce red glass substrate-1. In addition, except that the red pigment ink-2 of application example 2 and the yellow pigment ink-1 of application example 3 were used, respectively, the red glass substrate-2, yellow Glass substrate-1 was produced.

  Each of the obtained glass substrates (color glass substrates) of each color had excellent spectral curve characteristics and excellent fastness such as light resistance and heat resistance. In addition, all the color glass substrates were excellent in optical properties such as light transmittance and contrast ratio.

(Examples 5-8, Comparative Examples 5-8: Pigment dispersion using a basic resin solution as a dispersant)
(A) Preparation of pigment dispersion-2
Each component shown in Table 11 was blended in the amount (parts) shown in Table 11 and stirred with a dissolver for 2 hours. After confirming that there was no pigment mass, the dispersion was processed using a horizontal media disperser to prepare a pigment dispersion. In Table 11, “synergist 4” is represented by the following structural formula (14), and “synergist 5” is represented by the following structural formula (15) (n = 1 to 2), each having a sulfonic acid group. It is a pigment derivative. The “acrylic resin” in Table 11 has a monomer composition of BzMA / MAA = 80/20 (mass ratio), Mn of 5500 by GPC measurement, and PDI of 2.02 (solid content concentration is Measured with 30% PGMAc solution).

(D) Evaluation of pigment dispersion-2
The measurement result of the average particle size of the pigment contained in the pigment dispersion, the initial viscosity of the pigment dispersion, and the temperature of the pigment dispersion having the composition shown in Table 11 prepared above were left at 45 ° C. for 3 days. The measurement results of the later viscosity (viscosity after storage) are summarized in Table 12. The viscosity was measured using an E-type viscometer at 60 rpm and 25 ° C.

  As shown in Table 12, the average particle diameter of the pigments contained in the pigment dispersions of Examples 5 to 8 was all about 35 nm, and it was found that the finely divided pigment was sufficiently finely dispersed. did. In addition, in any of the pigment dispersions of Examples 5 to 8 using the pigment dispersant obtained in Synthesis Examples 4 to 6, the initial viscosity was 10 mPa · s or less. Moreover, when the initial viscosity and the viscosity after storage were compared, it was confirmed that the viscosity change was extremely small. From the above results, it is clear that the pigment dispersions of Examples 5 to 8 using the basic resin solutions obtained in Synthesis Examples 4 to 6 as dispersants have sufficient dispersion stability.

  On the other hand, the pigment dispersion of Comparative Example 5 using a basic resin solution by random polymerization as a dispersing agent was compared with the same pigment dispersion of Example 7 and a pigment dispersion using synergists. It can be seen that the average particle size of is not sufficiently finely dispersed. Furthermore, since the viscosity after storage was greatly increased, it was found that the dispersion stability was insufficient. This is presumably because the resin structure of the resin solution used as the dispersant in Comparative Example 5 was random, that is, the steric effect sufficient to stabilize the dispersion could not be exhibited, so that the dispersion could not be achieved.

  As shown in Table 12, the pigment dispersions of Comparative Examples 6 and 7 showed good values similar to those of Examples 6 and 7 in both average particle diameter and initial viscosity, but the viscosity after storage increased. This is because the resin solution used for the dispersant did not have OEMA introduced into the polymer block of B, which is the adsorptive chain of the pigment, or HEMA was introduced instead of OEMA. The action is weak, and it is considered that the pigment aggregated over time.

  On the other hand, in the pigment dispersion liquid of Comparative Example 8 using a resin solution that does not use OEMA or HEMA as a monomer unit as a dispersant, both the average particle diameter and the initial viscosity showed good values as in Example 8. Example 8 and Comparative Example 8 are organic pigments in which the pigment to be dispersed has no carbonyl group, amino group, amide group, ureido group, or imide group in the cyclic structure in the molecule. Since this is an example using PPG58, in such a system, when the dispersant of the example including OEMA is used in the polymer block of B which is a feature of the present invention, it is a matter of course that the dispersant of the comparative example not including It has been found that sufficient dispersibility can also be obtained when using.

(Application examples 4 to 6: Application to resists for color filters)
(A) Preparation of Color Filter Resist Ink Each component shown in Table 13 containing the pigment dispersions of Examples 4 to 6 was blended in the amounts (parts) shown in Table 13, and mixed well with a mixer to obtain a color. A pigment colorant composition (pigment ink) for a color filter of each color as a resist was obtained. The “photosensitive acrylic resin varnish” in Table 13 is a varnish containing an acrylic resin obtained by reacting glycidyl methacrylate with a BzMA / MAA copolymer. This acrylic resin had Mn of 6000, PDI of 2.38, and an acid value of 110 mgKOH / g. In Table 13, “TMPTA” represents trimethylolpropane triacrylate, “HEMPA” represents 2-hydroxyethyl-2-methylpropionic acid, and “DEAP” represents 2,2-diethoxyacetophenone.

(B) Evaluation of color filter resist ink A glass substrate treated with a silane coupling agent was set on a spin coater. The red pigment ink-3 of Application Example 4 was spin-coated on a glass substrate at 300 rpm for 5 seconds. After pre-baking at 80 ° C. for 10 minutes, exposure was performed with a light amount of 100 mJ / cm ² using an ultra-high pressure mercury lamp to produce red glass substrate-3. Moreover, the same operation was performed also about the application examples 5-6, and the glass substrate of each color was manufactured.

  Each of the obtained glass substrates (color glass substrates) of each color had excellent spectral curve characteristics and excellent fastness such as light resistance and heat resistance. In addition, all the color glass substrates were excellent in optical properties such as light transmittance and contrast ratio.

(Application example 7: Application to a colorant for ultraviolet curable inkjet ink)
(A) Preparation of pigment dispersion 39.4 parts of neutral resin solution UP-7 previously synthesized in Synthesis Example 7, 60.7 parts of isobornyl acrylate, titanium oxide (JR-405, manufactured by Teika Corporation, 100 parts of an average particle size of 240 nm) was added and mixed, followed by stirring with a dissolver for 2 hours. After confirming that there was no pigment mass, the dispersion was processed using a horizontal media disperser to prepare a pigment dispersion. The resulting white (W) pigment dispersion was passed through a 10 μm filter and a 5 μm filter. At this time, there was no filter clogging.

(B) Evaluation of pigment dispersion The average particle diameter of the pigment contained in the white pigment dispersion obtained above was 241 nm, and the viscosity was 10.7 mPa · s. The obtained white pigment dispersion is put into a light-shielded glass bottle and left in a thermostatic bath set at 60 ° C. for one month to check the viscosity and particle diameter change, the presence or absence of a supernatant, and the presence or absence of a sediment. It was tested whether it was not shaken. As a result, the average particle size was 242 nm and the viscosity was 10.8 mPa · s. No change in physical properties due to storage was observed, and it was confirmed that high dispersion stability was maintained. The supernatant was not seen at all. Although some sediment was confirmed, when it was scratched with a spatula, a slightly viscous sediment was observed. Next, when it was infiltrated, almost no sediment was found, and the original pigment dispersion was restored. When this average particle diameter was measured, it was 244 nm, and the average particle diameter was slightly increased because the precipitate was agglomerated, but it was confirmed that the precipitate was dispersed again and became a good pigment dispersion state. .

  Since the white pigment dispersion of Application Example 7 is highly dispersed and highly stable, the UV curable ink, in particular, there is no aggregation of the pigment, the fine particles are dispersed, and it is highly stable and can be precipitated. Since dispersion is restored again, it is considered to be optimal for ultraviolet curable inkjet inks that require ejection stability and high-speed printability.

(Application Example 8: Application to oil-based inkjet ink)
(A) Preparation of Pigment Dispersion 31.7 parts of the acidic resin solution UP-8 synthesized in Synthesis Example 8 above, 2 parts of “Synergist 6” represented by the following structural formula (16), and DEGME as a solvent 79.6 parts and 20 parts of PR122 (manufactured by Dainichi Seika Kogyo Co., Ltd., average particle size 100 nm) were added and mixed, and stirred with a dissolver for 2 hours. After confirming that there was no pigment mass, the dispersion was processed using a horizontal media disperser to prepare a pigment dispersion. The obtained magenta color pigment dispersion was passed through a 10 μm filter and a 5 μm filter. At this time, there was no filter clogging.

(B) Evaluation of pigment dispersion The average particle diameter of the pigment contained in the obtained magenta pigment dispersion was 101 nm, and the viscosity was 11.5 mPa · s. Even after storage at 70 ° C. for 1 week, there was no change in the average particle size and viscosity of the pigment dispersion, and it was very stable.

  The pigment dispersion obtained above was converted into an ink using an oil-based color for inkjet ink, filled in an ink cartridge, and solid-printed on a surface-treated 50 μm PET film by an inkjet printer. The obtained printed matter had a high optical density and a gloss value, had no printing twist, and had good scratch resistance.

  According to the present invention, by using an AB block copolymer having a polymer block into which a cyclic ureido group is introduced as a pigment dispersant, a pigment, particularly a difficult-to-disperse pigment, in an intramolecular cyclic structure. An organic pigment having a carbonyl group and / or an amino group as an independent group, or at least one group selected from the group of an amide group, a ureido group and an imide group in which a carbonyl group and an amino group are bonded Provided is a pigment dispersion that imparts a high degree of fine dispersion and storage stability to organic pigments. Specifically, it is possible to obtain a pigment dispersion liquid that is finely dispersed at a high level that cannot be realized by a conventional dispersant and that has high storage stability. This pigment dispersion is very suitable as a colorant for paints, inks, coating agents and the like, particularly as a colorant for inkjet inks and color filters that require high levels of fine particle formation and storage stability. Expected to be used.

Claims (11)

In a pigment dispersion having at least a pigment, a pigment dispersant and an organic solvent,
Furthermore, it comprises a dye derivative having a basic functional group or a dye derivative having an acid functional group,
The pigment dispersant is an AB block copolymer in which 90% by mass or more of the monomer units constituting the polymer are methacrylic acid monomers, and
The A-B block copolymers of the polymer which is one of the polymer blocks constituting the B polymer block of the mini, as a monomer unit represented by the following formula (1) represented by 2- (2-oxo-imidazolidin-1-yl) include ethyl methacrylate, it has a cyclic ureide groups introduced by the annular ureido methacrylate in the polymer block B,
When the pigment derivative has a basic functional group, the AB block copolymer has a constitution of a methacrylic acid monomer in which the polymer block of B further has a carboxy group or a phosphate group as the monomer unit. And having a carboxy group or a phosphate group introduced by the monomer,
When the dye derivative has an acidic functional group, the AB block copolymer has a constitution in which the polymer block of B further includes a methacrylic acid monomer having an amino group as the monomer unit, and the monomer. A pigment dispersion characterized by having an amino group introduced by

  The pigment is an organic pigment having a carbonyl group and / or an amino group as an independent group in the cyclic structure in the molecule, or an amide group, a ureido group and a carbonyl group and an amino group bonded to each other. The pigment dispersion according to claim 1, which is an organic pigment having at least one group selected from the group of imide groups.   The pigment dispersion according to claim 1 or 2, wherein the organic solvent is an aprotic solvent and has a dielectric constant ε of 25 or less. Polymer block of the which is the other polymer block constituting the A-B block copolymer A is the number average molecular weight in terms of polystyrene in the gel permeation chromatograph 1,000 to 10,000, and the dispersity showing the distribution of the molecular weight ( (Weight average molecular weight / number average molecular weight) is 1.5 or less,
The content of 2- (2-oxoimidazolidin-1-yl) ethyl methacrylate in the polymer block of B is 5 to 30% by mass,
The pigment dispersion according to any one of claims 1 to 3 , wherein the AB block copolymer has a number average molecular weight of 3000 to 15000 and a dispersity of 1.6 or less. The pigment, the pigment dispersant, and the organic solvent are within a range of 5 to 20% by mass of the pigment, 0.5 to 30% by mass of the pigment dispersant, and 50 to 94.5% by mass of the organic solvent. The pigment dispersion liquid according to any one of claims 1 to 4 , which is blended. The pigment, diketopyrrolopyrrole pigment, pigment dispersion according to any one of claims 1 to 5, at least one selected from the group consisting of quinophthalone pigments and anthraquinone pigments. The pigment dispersion according to any one of claims 1 to 6 , wherein the organic solvent is a propylene glycol-based organic solvent. The AB block copolymer is included in the range of 10 to 150 parts by mass with respect to 100 parts by mass of the pigment in which the pigment and the pigment dispersant are deposited and encapsulated on the pigment surface. The pigment dispersion according to any one of claims 1 to 7 , which is in the form of a resin-treated pigment in which dispersibility is imparted to the pigment by a pigment dispersant. A method for producing an AB block copolymer for producing the AB block copolymer according to claim 1 , comprising:
It has a step of living radical polymerization of monomer units constituting the AB block copolymer in the presence of at least a polymerization initiating compound and a catalyst, and the polymerization initiating compound used in this step is at least one of iodine or an iodine compound And the catalyst used in the step is at least one selected from the group consisting of phosphorus halides, phosphite compounds, phosphinate compounds, imide compounds, phenol compounds, diphenylmethane compounds and cyclopentadiene compounds. Ri compound der species,
90% by mass or more of the monomer units constituting the AB block copolymer are methacrylic acid monomers,
2- (2-oxoimidazolidin-1-yl) ethyl methacrylate represented by the following formula (1) is used only for the monomer unit of the polymer block of B, and carboxy is further added to the monomer unit of the polymer block of B. A method for producing an AB block copolymer, wherein a methacrylic acid monomer having a group or a phosphoric acid group is used, or a methacrylic acid monomer having an amino group is further used .

A method for producing a pigment dispersion for obtaining the pigment dispersion according to claim 8 , comprising:
A method for producing a pigment dispersion, comprising the step of dispersing the resin-treated pigment in the organic solvent. A resin-treated pigment in which a pigment dispersant is deposited on the surface of a pigment treated with a pigment derivative, and the dispersibility is imparted to the encapsulated pigment,
The pigment dispersant is an AB block copolymer in which 90% by mass or more of the monomer units constituting the polymer are methacrylic acid monomers ,
Only the polymer block of B which is one of the polymer blocks constituting the AB block copolymer was introduced by 2- (2-oxoimidazolidin-1-yl) ethyl methacrylate represented by the following formula (1). In the case where the polymer block of B has a cyclic ureido group and the dye derivative has a basic functional group, it has a carboxy group or a phosphate group, or the dye derivative has an acidic functional group. If it has an amino group,
With respect to 100 parts by weight of the pigment, the resin treated pigment characterized by comprising Nde contains the A-B block copolymer in the range of 10 to 150 parts by weight.