JP5637539B2 - Pigment dispersant and method for producing the same, pigment colorant composition, and pigment colorant composition for color filter - Google Patents

Description

  The present invention relates to a pigment dispersant, a pigment colorant composition using the pigment dispersant, and a pigment colorant composition for a color filter using the pigment colorant composition.

  With the recent rapid development of information devices, liquid crystal color displays are widely used as information display members for information devices. Applications of liquid crystal color displays include, for example, televisions, projectors, personal computers, mobile information devices, monitors, car navigation systems, mobile phones, display screens of electronic computers and electronic dictionaries, information bulletin boards, guidance bulletin boards, function display boards, Examples include signs and other displays, and digital camera and video camera shooting screens. The liquid crystal color display used for such various uses is equipped with a color filter. The color filter is required to have excellent image characteristics such as fineness, color density, light transmission, and contrast, and color characteristics and optical characteristics.

  A color stabilizer for a color filter (hereinafter also referred to as “color for color filter”) used for the three primary color pixels of a conventional color filter uses a dispersion stabilizer together with a pigment. Examples of the dispersion stabilizer include (a) a dye derivative (hereinafter referred to as “dye”) having a skeleton similar to a pigment, generally referred to as “synergist”, and having an acid group such as a sulfonic acid group introduced into the skeleton. The derivative is simply referred to as “synergist”) and (b) a basic polymer type pigment dispersant having an amino group that is paired with the acidic group of the dye derivative (synergist) is used. There are many cases (see, for example, Patent Document 1). By using such a combination of (a) a dye derivative (synergist) and (b) a polymer type pigment dispersant, not only can the dispersion stability of the pigment in an organic solvent be improved, but also the resulting pigment The viscosity of the ink can be lowered and the long-term storage stability of the ink can be improved.

  However, color filters for liquid crystal color televisions are required to further improve color display performance (pixel performance) such as color density, light transmission, and contrast ratio. And in order to improve the performance of a pixel, it exists in the tendency which makes the particle diameter of the pigment to be used small and makes it ultrafine. As a result, the ultrafine pigment has an increased number of particles and an increased surface area even if the mass is the same as that of the non-ultrafine pigment. For this reason, it is difficult to sufficiently maintain the dispersion stability of the pigment by the conventional technique.

  In order to stably disperse the ultrafine pigment, there is a method of increasing the use amount of a synergist having an acidic group and a pigment dispersant (for example, see Patent Document 2). However, since the pigment density is relatively lowered, the color density (high color density of the pixel) cannot be satisfied. In other words, it is very difficult to provide an ink that satisfies both the requirement of increasing the pigment content in order to increase the color density of the pixel to obtain an appropriate pixel coating composition and the dispersion stability of the pigment.

  In order to improve the relative decrease in the pigment concentration, a method of introducing an acidic group into the molecular structure of the pigment dispersant is conceivable (for example, see Patent Document 3). However, this method is difficult to apply to basic pigment dispersants having amino groups. In a combination of a synergist having an acidic group and a basic polymer type pigment dispersant having an amino group, if an acidic group is introduced into the molecular structure of the pigment dispersant, the acidic group and amino group This is because the group may be ionically bonded. When the acidic group and the amino group are ionically bonded, the pigment dispersant may be gelled in the organic solvent. Even if the pigment dispersant does not gel, an ionic bond exists in the molecule of the pigment dispersant or between molecules, so that the pigment dispersant and the synergist are difficult to ion bond. For this reason, the pigment dispersant having an ionic bond may not function sufficiently as a pigment dispersant.

  By the way, color filters are usually coated with color filter color on glass, exposed to only necessary parts using a photomask, etc. and insolubilized, and then unexposed parts (unnecessary parts) are removed with an alkaline developing aqueous solution. It is manufactured by the method. A developing polymer having an acidic group such as a carboxyl group is added to the color for the color filter. For this reason, the acidic group of the developing polymer is neutralized with an aqueous alkaline developing solution, and the developing polymer is solubilized in water and removed. However, a basic pigment dispersant having an amino group cannot be dissolved in an alkaline developing aqueous solution because an acidic group cannot be introduced into its molecular structure. For this reason, it has been a cause of deteriorating developability such as a long development time or a sharp pixel edge.

JP-A-9-176511 JP 2001-240780 A JP 2008-298967 A

  The present invention has been made in view of the above problems existing in the prior art, and the problem is that the finely divided pigment can be highly finely dispersed and has excellent long-term storage stability. Another object of the present invention is to provide a pigment dispersant capable of preparing a pigment colorant composition and a method for producing the same. Another object of the present invention is to provide a pigment colorant composition having excellent coating properties and long-term storage stability.

  Furthermore, the subject of the present invention is a liquid crystal color television having excellent coating characteristics and long-term storage stability, and excellent optical characteristics such as pixel color density, definition, contrast, and transparency. It is another object of the present invention to provide a pigment colorant composition for a color filter capable of producing a color filter equipped in the information display device.

  As a result of diligent research, the present inventors have shown that a sulfonic acid group-containing acrylic polymer obtained by reacting a specific hydroxyl group-containing acrylic polymer with 2-sulfobenzoic anhydride exhibits excellent properties as a pigment dispersant. In addition, when this sulfonic acid group-containing acrylic polymer is used as a pigment dispersant, it is possible to highly finely disperse the finely divided pigment and to prepare a pigment colorant composition having excellent long-term storage stability. As a result, the present invention has been completed.

That is, according to the present invention, the following pigment dispersant is provided.
[1] on the edge end of it to the hydroxyl group-containing acrylic polymer having one or more hydroxyl groups, 2-sulfo by reacting benzoic anhydride obtained, sulfonic acid group-containing acrylic having a sulfonic acid group at an end thereof A pigment dispersant comprising a polymer.
[2] The sulfonic acid group-containing acrylic polymer has a number average molecular weight of 2,000 to 20,000, an acid value of 10 to 250 mgKOH / g, and an acid value derived from the sulfonic acid group of 10 to 10. The pigment dispersant according to [1], which is 100 mg KOH / g.
[3] The pigment dispersant according to [1] or [2], wherein the sulfonic acid group-containing acrylic polymer contains 5 to 30% by mass of a structural unit derived from an addition polymerizable monomer having a carboxyl group .
[4] before Symbol hydroxyl, pigment according to any one of [1] to [3] derived from an azo-based radical polymerization initiator or a chain transfer agent having one or more hydroxyl groups having one or more hydroxyl groups Dispersant.

Moreover, according to this invention, the manufacturing method of the pigment dispersant shown below is provided.
[5] above [1] to [4] A manufacturing method of a pigment dispersing agent according to any one of a hydroxyl group-containing acrylic polymer having one or more hydroxyl groups in the end the end of its 2-sulfobenzoic A method for producing a pigment dispersant, comprising a step of reacting an acid anhydride to obtain a sulfonic acid group-containing acrylic polymer having a sulfonic acid group at its terminal .

Furthermore, according to the present invention, the following pigment colorant composition is provided.
[ 6 ] A pigment colorant composition comprising the pigment dispersant according to any one of [1] to [ 4 ] and a pigment having a number average particle diameter of 10 to 150 nm.
[ 7 ] The pigment colorant composition according to [ 6 ], further including a dye derivative having a basic functional group.

Moreover, according to this invention, the pigment colorant composition for color filters shown below is provided.
[ 8 ] A pigment colorant composition for a color filter, which is obtained using the pigment colorant composition described in [ 6 ] or [ 7 ].

  The pigment dispersant of the present invention can highly finely disperse a finely divided pigment and can prepare a pigment colorant composition having excellent long-term storage stability. Further, according to the method for producing a pigment dispersant of the present invention, a pigment dispersant capable of highly finely dispersing a finely divided pigment and preparing a pigment colorant composition having excellent long-term storage stability. Can be easily produced.

  Furthermore, the pigment colorant composition of the present invention has a low viscosity that is stably maintained for a long period of time and has excellent coating properties. In addition, the pigment colorant composition for a color filter of the present invention has excellent coating properties and long-term storage stability, and also has excellent optical properties such as pixel color density, definition, contrast, and transparency. It is possible to manufacture color filters equipped in information display devices such as color televisions. In addition, if the pigment colorant composition for a color filter of the present invention is used, a color filter resist having excellent developability during alkali development can be obtained.

  Next, the present invention will be described in more detail with reference to an embodiment for carrying out the present invention. The pigment dispersant of the present invention is a sulfonic acid group obtained by reacting a 2-sulfobenzoic anhydride represented by the following formula with a hydroxyl group-containing acrylic polymer having one or more hydroxyl groups at its side chain or terminal. It consists of a containing acrylic polymer.

  It is known that 2-sulfobenzoic anhydride represented by the above formula reacts with a hydroxyl group to become a carboxylic acid ester and a sulfonic acid. By reacting this 2-sulfobenzoic anhydride with a hydroxyl group-containing acrylic polymer, a sulfonic acid group can be easily introduced to obtain a sulfonic acid group-containing acrylic polymer. The sulfonic acid group-containing acrylic polymer thus obtained is adsorbed to a basic dye derivative having a pigment or an amino group by an adsorbing action such as an ionic bond or a hydrogen bond of the introduced sulfonic acid group. Can be highly finely dispersed, and the stability of the pigment can be improved.

  As a method for introducing a sulfonic acid group into the structure of an acrylic polymer, for example, an addition polymerizable monomer having a sulfonic acid group (hereinafter, “addition polymerizable monomer” is also simply referred to as “monomer”) is polymerized. There is a way to do it. A monomer having a sulfonic acid group is considered to have reactivity with an unsaturated bond. For this reason, the sulfonic acid group in the monomer is usually in a salt state such as a metal salt or an amine salt, or in an ester state in many cases. A monomer having a sulfonic acid group in a salt state does not dissolve in most organic solvents. For this reason, it is difficult to produce a sulfonic acid group-containing acrylic polymer by polymerizing a monomer having a sulfonic acid group in a salt state. Further, since the sulfonic acid group is in a salt state, the monomer may contain water or may be an aqueous solution. For this reason, when it superposes | polymerizes using the monomer which has a sulfonic acid group in a salt state, it is necessary to remove a water | moisture content after superposition | polymerization. Further, after polymerization, the sulfonate must be returned to the sulfonic acid, and the ester must be hydrolyzed.

  There are also monomers having sulfonic acid groups, but such monomers are generally very poorly soluble in organic solvents. A specific example of the monomer having a sulfonic acid group is dimethylpropanesulfonic acid acrylamide. This dimethylpropanesulfonic acid acrylamide is slightly soluble in alcohol and the like, but hardly dissolved in general organic solvents other than alcohol.

  In addition to the above, as a method of introducing a sulfonic acid group into an acrylic polymer, there is a method of reacting a sulfonating agent such as chlorosulfonic acid, sulfuric acid, or sulfur dioxide with an acrylic polymer. However, when these sulfonating agents are used, the acrylic polymer may be decomposed.

  The sulfonic acid group-containing acrylic polymer constituting the pigment dispersant of the present invention uses 2-sulfobenzoic anhydride represented by the above formula so that sulfonic acid groups can be easily formed in the structure of the acrylic polymer. It has been introduced. Since 2-sulfobenzoic anhydride is an acid anhydride obtained by dehydration condensation of a sulfonic acid group and a carboxyl group, the solubility in an organic solvent is sufficiently high. Moreover, 2-sulfobenzoic anhydride has high reactivity with a hydroxyl group. For this reason, it can be easily made into a sulfonic acid group containing acrylic polymer by making 2-sulfobenzoic anhydride react with a hydroxyl group containing acrylic polymer.

  It is also conceivable to produce a sulfonic acid group-containing acrylic polymer by polymerizing a sulfonic acid group-containing monomer obtained by reacting 2-sulfobenzoic anhydride with a monomer having a hydroxyl group. However, as described above, since the sulfonic acid group-containing monomer is difficult to dissolve in an organic solvent, even when the sulfonic acid group-containing monomer is polymerized, the polymerization reaction is not completed or a side reaction tends to occur. It is in. For this reason, the sulfonic acid group-containing acrylic polymer can be obtained easily and in high yield by reacting the hydroxyl group-containing acrylic polymer with 2-sulfobenzoic anhydride.

  The reaction between 2-sulfobenzoic anhydride and the hydroxyl group-containing acrylic polymer is carried out by a conventionally known method and is not particularly limited. The reaction is preferably carried out in an organic solvent at a reaction temperature in the range of -20 to 100 ° C. Moreover, since 2-sulfobenzoic anhydride has high reaction activity, it is not necessary to use a catalyst. However, if necessary, an acidic catalyst such as sulfuric acid or p-toluenesulfonic acid; a basic catalyst such as triethylamine, pyridine, or 1,8-diazabicyclo [5,4,0] -7-undecene may be used.

Next, the hydroxyl group-containing acrylic polymer will be described.
Examples of the hydroxyl group-containing acrylic polymer that is a precursor of the sulfonic acid group-containing acrylic polymer constituting the pigment dispersant of the present invention include (1) and (2) shown below.
(1) An acrylic polymer obtained by radical polymerization of an addition polymerizable monomer having a hydroxyl group.
(2) (2-1) Acrylic polymer having a hydroxyl group at the end obtained by polymerization using an azo radical polymerization initiator having one or more hydroxyl groups, or (2-2) one hydroxyl group An acrylic polymer having a hydroxyl group at its terminal, obtained by polymerization using the chain transfer agent as described above.

First, the acrylic polymer (1) will be described.
The addition polymerizable monomer having a hydroxyl group used for obtaining the acrylic polymer (1) is not particularly limited, and examples thereof include 2-hydroxyethyl (meth) acrylate and 2-hydroxy (meth) acrylate. Propyl, 3-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, hydroxymethylcyclohexylmethyl (meth) acrylate, glycerol (meth) acrylate, poly (meth) acrylate poly (n ≧ 2) Examples include ethylene glycol and (meth) acrylic acid poly (n ≧ 2) propylene glycol.

  The acrylic polymer (1) may be a homopolymer of an addition polymerizable monomer having a hydroxyl group. However, from the viewpoint of adjusting the amount of sulfonic acid group introduced, it is preferably a copolymer of an addition polymerizable monomer having a hydroxyl group and “other monomer”. As the “other monomer”, a monomer having no amino group or a monomer having no reactivity (or low reactivity) with a sulfonic acid group and a carboxyl group is preferable. If a monomer having an amino group is used as the “other monomer”, the sulfonic acid group and the amino group may be ionically bonded, and the resulting sulfonic acid group-containing acrylic polymer may be insoluble in an organic solvent. . In addition, when a monomer having reactivity (or high reactivity) with a sulfonic acid group and a carboxyl group is used, a crosslinking reaction may occur during polymerization to cause gelation.

  Specific examples of “other monomers” include (meth) acrylates of aliphatic and alicyclic alcohols such as methyl (meth) acrylate, n-butyl (meth) acrylate, cyclohexyl (meth) acrylate; ) (Meth) acrylates containing aromatic rings such as benzyl acrylate and phenoxyethyl (meth) acrylate; (meth) acrylates of glycols such as methoxyethyl (meth) acrylate and ethoxyethoxyethyl (meth) acrylate; Examples include amide monomers such as (meth) acrylamide and N-isopropylacrylamide; aromatic vinyl compounds such as styrene and vinyltoluene; vinyl ethers; vinyl esters.

Next, the acrylic polymer (2) will be described.
The acrylic polymer of (2-1) is, for example, an azo radical polymerization having at least one hydroxyl group when polymerized using the addition polymerizable monomer having a hydroxyl group exemplified in the acrylic polymer of (1). It is an acrylic polymer having a hydroxyl group at its end, obtained by using an initiator. The azo radical polymerization initiator having one or more hydroxyl groups is not particularly limited. For example, 2,2′-azobis (2-methyl-N- [1,1-bis (hydroxymethyl) -2-hydroxyethyl] ] Propionamide), 2,2'-azobis (2-methyl-N- [2- (1-hydroxybutyl)] propionamide), 2,2'-azobis (2-methyl-N- [2- (1 -Hydroxyethyl)] propionamide), 4,4'-azobis (4-cyanovaleric acid) carboxyl group and the compound obtained by reacting with an epoxy group or two or more hydroxyl groups.

  The acrylic polymer of (2-2) is a chain transfer having one or more hydroxyl groups when polymerized using, for example, an addition polymerizable monomer having a hydroxyl group exemplified for the acrylic polymer of (1). It is an acrylic polymer obtained by using an agent and having one or more hydroxyl groups at its ends. The chain transfer agent having one or more hydroxyl groups is not particularly limited, and examples thereof include hydroxyethyl thiol and thioglycerol. Furthermore, for example, a thiol chain transfer agent having a plurality of hydroxyl groups obtained by reacting glycidol with a compound such as thiomalic acid having one thiol group and a plurality of carboxyl groups can also be used.

  In consideration of use in a pigment colorant composition for a color filter to be described later, in order to obtain a pigment dispersant capable of alkali development, the acrylic polymers of (1) and (2) above are addition polymerizations having a carboxyl group. It is preferable that it contains a structural unit derived from a functional monomer. The addition polymerizable monomer having a carboxyl group is not particularly limited, and examples thereof include (meth) acrylic acid, acrylic acid dimer, maleic acid, itaconic acid, fumaric acid, and 2-hydroxyethyl (meth) acrylate. An ester type monomer obtained by reacting a hydroxyl group-containing acrylic monomer with an acid anhydride such as phthalic anhydride or cyclohexene dicarboxylic acid anhydride. It is also possible to introduce a carboxyl group into the acrylic polymer by hydrolyzing the lower alcohol ester. Since the carboxyl group is less acidic than the sulfonic acid, the sulfonic acid group is preferentially ionically bonded to a basic synergist having a functional group such as an amino group described later. For this reason, even if a carboxyl group is introduced into the acrylic polymer, fine particles of the pigment can be dispersed well.

  The ratio of the structural unit derived from the addition polymerizable monomer having a carboxyl group contained in the hydroxyl group-containing acrylic polymer is preferably 5 to 30% by mass when the total structural unit is 100% by mass. If the content of the structural unit derived from the addition polymerizable monomer having a carboxyl group is less than 5% by mass, the effect on alkali development may not be obtained. On the other hand, if it exceeds 30% by mass, the proportion of the carboxyl group in the hydroxyl group-containing acrylic polymer becomes too large, and the dispersibility of the pigment may be lowered.

  Next, details of the sulfonic acid group-containing acrylic polymer will be described.

First, the case where the acrylic polymer (1) is used will be described.
A hydroxyl group-containing acrylic polymer in which hydroxyl groups are randomly arranged in the side chain can be obtained by performing conventionally known radical polymerization using at least the addition polymerizable monomer having a hydroxyl group as a constituent component. By reacting the hydroxyl group of the obtained hydroxyl group-containing acrylic polymer with 2-sulfobenzoic anhydride, a sulfonate group-containing acrylic in which a sulfonate group is introduced at the position of the hydroxyl group randomly arranged in the side chain. Based polymers can be obtained. When the obtained sulfonic acid group-containing acrylic polymer (pigment dispersant) is used to disperse the pigment, the pigment is dispersed between the sulfonic acid group and the pigment in a structure called “train-loop-tail”. Adsorption of the agent occurs. That is, the sulfonic acid group randomly arranged in the pigment dispersant is partially adsorbed on the pigment, whereby the pigment is dispersed in a good state.

  The radical polymerization may be performed according to a conventionally known method. In a conventionally known organic solvent, an azo polymerization initiator such as 2,2′-azobisisobutyronitrile; a peroxide initiator such as benzoyl peroxide is preferably used as the radical polymerization initiator. Further, a thiol chain transfer agent such as dodecyl mercaptan can be used as necessary. The polymerization temperature is preferably 40 to 150 ° C, and more preferably 50 to 100 ° C.

  If the hydroxyl-containing acrylic polymer having a random structure obtained as described above is used, a sulfonic acid group-containing acrylic polymer (pigment dispersant) capable of dispersing the pigment in a good state can be obtained.

  The acrylic polymer (2) can be produced by a conventionally known radical polymerization using an azo radical polymerization initiator having a hydroxyl group or a chain transfer agent. Further, in the case of the above-mentioned living radical polymerization, it is preferable to use a compound having a hydroxyl group as an initiating compound for starting the living radical polymerization. In addition, the kind of starting compound is not specifically limited. By reacting the hydroxyl group of the hydroxyl group-containing acrylic polymer thus obtained with 2-sulfobenzoic anhydride, a sulfonic acid group-containing acrylic polymer having a sulfonic group introduced at the position of the hydroxyl group is obtained. be able to.

  The number average molecular weight (hereinafter also referred to as “Mn”) of the sulfonic acid group-containing acrylic polymer constituting the pigment dispersant is preferably 2,000 to 20,000, and 5,000 to 15,000. More preferably. When the Mn of the sulfonic acid group-containing acrylic polymer is less than 2,000, the molecular weight is too small, the long-term stability of the resulting pigment colorant composition may not be achieved, and when used in articles The physical properties tend to decrease. On the other hand, if it exceeds 20,000, one molecular chain is likely to be adsorbed on a plurality of pigment particles, and the dispersibility of the pigment tends to be difficult to improve. In addition, the “number average molecular weight (Mn)” in the present invention means a value in terms of polystyrene measured by gel permeation chromatography (GPC).

  The acid value of the sulfonic acid group-containing acrylic polymer is preferably 10 to 250 mgKOH / g, and more preferably 50 to 200 mgKOH / g. Of the acid values of the sulfonic acid group-containing acrylic polymer, the acid value derived from the sulfonic acid group is preferably 10 to 100 mgKOH / g, and more preferably 50 to 100 mgKOH / g. If the acid value derived from the sulfonic acid group is too large (the amount of the sulfonic acid group is too large), one molecular chain is likely to be adsorbed to a plurality of pigment particles. There is a tendency for the solubility to declining. In addition, when the total acid value exceeds 250 mgKOH / g, since the amount of acidic groups (acid groups) is too large, the hydrophilicity of the sulfonic acid group-containing acrylic polymer increases, and the water resistance tends to decrease. is there.

Next, the pigment colorant composition of the present invention will be described.
The pigment colorant composition of the present invention contains the pigment dispersant described above and a pigment. As the pigment, an organic pigment is preferable. A known organic pigment can be used as the organic pigment. Specific examples of organic pigments include quinacridone pigments, anthraquinone pigments, diketopyrrolopyrrole pigments, perylene pigments, phthalocyanine blue pigments, phthalocyanine green pigments, isoindolinone pigments, indigo / thioindigo pigments, dioxazines 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, and azomethine azo black Mention may be made of red, green, blue, yellow, orange, purple and black pigments selected from the group consisting of pigments.

  The number average particle diameter of the pigment is 10 to 150 nm, and preferably 20 to 80 nm. By thus finely dispersing the pigment, high transparency and high contrast can be achieved even when the pigment colorant composition is used in a color filter. The pigment colorant composition of the present invention contains the above-described pigment dispersant capable of highly finely dispersing finely divided pigments. Therefore, in the pigment colorant composition of the present invention, the extremely fine pigment as described above is dispersed in a good state and excellent in long-term storage stability.

  As the pigment, it is preferable to select a pigment used in a color filter. Examples of the red pigment include color index (hereinafter, CI) pigment red (PR) 56, 58, 122, 166, 168, 176, 177, 178, 224, 242, 254, and 255. Examples of green pigments include C.I. I. Pigment green (PG) 7, 36, 58, poly (14-16) bromo copper phthalocyanine, poly (12-15) bromo-poly (4-1) chloro copper phthalocyanine. Examples of blue pigments include C.I. I. Pigment blue (PB) 15: 1, 15: 3, 15: 6, 60, 80.

  Moreover, the following can be mentioned as a complementary color pigment with respect to said pigment, or a multicolor type pixel pigment. Examples of yellow pigments include C.I. I. Pigment Yellow (PY) 12, 13, 14, 17, 24, 55, 60, 74, 83, 90, 93, 126, 128, 138, 139, 150, 154, 155, 180, 185, 216, 219, C . I. Pigment violet (PV) 19, 23 can be used. Examples of black pigments for black matrix include C.I. I. Pigment black (PBK) 6, 7, 11, 26, copper-manganese-iron-based composite oxide can be used.

  In the pigment colorant composition of the present invention, a basic dye derivative having a basic functional group is adsorbed by ionic bonding with the sulfonic acid group of the sulfonic acid group-containing acrylic polymer constituting the pigment dispersant. It is preferable to contain. This dye derivative has a basic functional group introduced into the dye skeleton. As the dye skeleton, the same or similar skeleton as the pigment and the same or similar skeleton as the compound used as the pigment raw material are preferable. Specific examples of the dye skeleton include azo dye skeleton, phthalocyanine dye skeleton, anthraquinone dye skeleton, triazine dye skeleton, acridine dye skeleton, and perylene dye skeleton.

  The basic functional group introduced into the dye skeleton is preferably an amino group. The amino group to be introduced may be any of primary, secondary, and tertiary amino groups, and may be a quaternary amino group ammonium salt. The basic functional group is preferably a sulfonamide group. A basic functional group such as an amino group may be directly bonded to the dye skeleton, but is bonded to the dye skeleton through a hydrocarbon group such as an alkyl group or an aryl group; an ester, an ether, a sulfone, or a urethane bond. May be.

  The pigment colorant composition of the present invention can also use an organic solvent, water, or a mixed solvent of water and a hydrophilic organic solvent as a medium. As the medium, an organic solvent is preferably used. Specific examples of the organic solvent include hydrocarbon solvents such as hexane and toluene; alcohol solvents such as butanol; ester solvents such as propyl acetate and butyl acetate; ketone solvents such as cyclohexanone and methyl isobutyl ketone; diethylene glycol monobutyl ether Glycol solvents such as propylene glycol monomethyl ether; glycol ester or ether solvents such as propylene glycol monomethyl ether acetate and dipropylene glycol dibutyl ether; amide solvents such as N-methylpyrrolidone and dimethylacetamide; ethylene carbonate and propylene carbonate And carbonate-based solvents. These organic solvents can be used individually by 1 type or in combination of 2 or more types.

  Conventionally known additives and resins may be added to the pigment colorant composition of the present invention. Examples of the additive include an ultraviolet absorber, a leveling agent, an antifoaming agent, and a photopolymerization initiator. The resin is usually used as a resin varnish. As the resin varnish, a photosensitive resin varnish containing a photosensitive resin or a non-photosensitive resin varnish containing a non-photosensitive resin is used. Specific examples of the photosensitive resin include a photosensitive cyclized rubber resin, a photosensitive phenol resin, a photosensitive polyacrylate resin, a photosensitive polyamide resin, a photosensitive polyimide resin, an unsaturated polyester resin, and a polyester. Examples thereof include acrylate resins, polyepoxy acrylate resins, polyurethane acrylate resins, polyether acrylate resins, polyol acrylate resins, and the like. These photosensitive resins can be used alone or in combination of two or more. In addition, the monomer as a reactive diluent may be added to the photosensitive resin varnish. Among the photosensitive resins, an alkali-developable acrylate resin having a free carboxylic acid group in the molecule is preferable.

  Specific examples of the non-photosensitive resin varnish include cellulose acetate resin, nitrocellulose resin, styrene (co) polymer, polyvinyl butyral resin, aminoalkyd resin, polyester resin, amino resin modified polyester resin, Polyurethane resin, acrylic polyol urethane resin, soluble polyamide resin, soluble polyimide resin, soluble polyamideimide resin, soluble polyesterimide resin, hydroxyethyl cellulose, water-soluble salt of styrene-maleic acid ester copolymer, ( Examples thereof include water-soluble salts of (meth) acrylic acid ester (co) polymers, water-soluble aminoalkyd resins, water-soluble aminopolyester resins, and water-soluble polyamide resins. These non-photosensitive resins can be used singly or in combination of two or more.

  You may mix | blend a pigment, a pigment dispersant, and a pigment derivative separately. It is also preferable to use a pigment (surface-treated pigment) whose surface is made basic by adding a dye derivative when the pigment raw material is made into a pigment or when the pigment is made finer. Furthermore, a pigment dispersant may be added in the presence or absence of a pigment derivative at the time of pigmentation or refinement, and the pigment may be treated with the pigment dispersant to form a resin-treated pigment.

  As described above, the pigment colorant composition of the present invention contains at least a pigment dispersant and a pigment, preferably further contains a pigment derivative, and an organic solvent, an additive, and a resin are added as necessary. Thus, the pigment is dispersed. The ratio of the pigment contained in the pigment colorant composition is preferably 5 to 40% by mass, more preferably 10 to 30% by mass, based on 100% by mass as a whole. Moreover, the amount of the pigment dispersant contained in the pigment colorant composition is preferably 5 to 300 parts by mass, more preferably 10 to 100 parts by mass with respect to 100 parts by mass of the pigment. The amount of the pigment derivative contained in the pigment colorant composition is preferably 1 to 50 parts by mass, more preferably 5 to 20 parts by mass with respect to 100 parts by mass of the pigment.

  The method for dispersing the pigment is not particularly limited as long as it is a conventionally known method. Examples of the apparatus used for dispersing the pigment include vertical and horizontal media mills, sand mills, attritors, microfluidizers, ultrasonic dispersers, and three rolls. It is preferable to use these devices to disperse the pigment until a predetermined number average particle diameter is obtained.

  The pigment colorant composition of the present invention can be used as a colorant for various articles, and can be used as gravure ink, offset ink, UV inkjet ink, and the like. In particular, it is suitable as a pigment colorant composition for color filters (colorant for color filters) because it can reduce viscosity and increase the fineness of pigments and has good long-term storage stability. The use as a colorant for the color filter is not particularly limited.

Next, the present invention will be described in more detail with specific examples. Hereinafter, “part” and “%” in the text are based on mass unless otherwise specified.
( Reference Example 1: Random polymer type pigment dispersant)
A polymerization reactor equipped with a water bath as a heating device, and further equipped with a polymerization vessel, a stirrer, a monomer dropping device, a reagent inlet, a backflow cooler, and a nitrogen gas inlet was prepared. A polymerization vessel was charged with 100 parts of propylene glycol monomethyl ether acetate (PGMAc) as a polymerization solvent. In a separate container, 43.5 parts methyl methacrylate (MMA), 25 parts butyl methacrylate (BMA), 25 parts 2-ethylhexyl methacrylate (2EHMA), 6.5 parts 2-hydroxyethyl methacrylate (HEMA), 2 parts of lauryl thiol and 3 parts of azobisisobutyronitrile (AIBN) were added and mixed to obtain a mixture. 1/3 amount of the obtained mixture was added to the polymerization vessel and heated to 80 ° C. When the temperature reached 80 ° C., the remaining 2/3 amount was dropped over 1.5 hours, and a polymerization reaction was performed at 70 to 80 ° C. for 8 hours under a nitrogen gas stream. This obtained the random polymer (PGMAc solution, solid content concentration: 41.2%) in which the hydroxyl group was arranged at random.

  A part of the obtained random polymer was sampled, and its molecular weight was measured by GPC using tetrahydrofuran as a solvent. As a result, Mn (hereinafter referred to as “RI-Mn”) using a differential refractive index (RI) detector was used. Was 6,500, and the molecular weight distribution (PDI) was 1.88. Further, when an ultraviolet absorption (UV) detector attached to GPC is used, an absorption peak is not detected, and Mn (hereinafter referred to as “UV-Mn”) when an ultraviolet absorption (UV) detector is used. ) Could not be measured.

PGMAc was added to the obtained random polymer to adjust the solid content concentration to 30%, and then cooled. 7.3 parts of 2-sulfobenzoic anhydride (SBA) was added and dissolved by stirring. Subsequently, it heated at 70 degreeC and made it react for 1 hour. Using an infrared spectrophotometer (IR), the disappearance of two peaks in the vicinity of 1,850 cm ^−1, which is a peak derived from sulfonic acid carboxylic anhydride of SBA, and 3,450 cm ⁻ from the hydroxyl group of a random polymer. ^The reaction was followed by a decrease in peak near ¹ . As a result, the peak derived from the sulfonic acid carboxylic anhydride of SBA disappeared 1 hour after the start of the reaction. In the vicinity of 1,700 cm ⁻¹ , no peak attributed to a carboxyl group was detected. From this, it was suggested that SBA reacted with the hydroxyl group of the random polymer to produce an ester group derived from a carboxyl group and a sulfonic acid. The solid concentration was measured and found to be 31.2%.

  When the molecular weight of the produced compound was measured by GPC, RI-Mn was 6,600 and PDI was 2.13. In addition, in GPC measurement, when the polymer before making SBA react was measured with the UV detector, the peak was hardly detected. On the other hand, when the polymer after reacting with SBA was measured with a UV detector, a peak was confirmed, UV-Mn was 6,500, PDI was 2.20, and differential refractive index (RI ) It was almost the same as the molecular weight (RI-Mn) when the detector was used. Thus, RI-Mn and UV-Mn were almost the same because the aromatic ring constituting SBA was introduced into the polymer, and the peak was confirmed by the UV detector due to the ultraviolet absorption ability of the aromatic ring. Conceivable.

  Next, the acid value of the obtained polymer was measured. Specifically, first, about 0.5 part of a sample was weighed and 50 ml of toluene / ethanol = 1/1 (volume / volume) was added to obtain a uniform solution. Neutralization titration was performed by gradually dropping 0.1N KOH ethanol solution using phenolphthalein as an indicator. As a result, the acid value of the polymer was 20.5 mgKOH / g. This acid value is an acid value derived from sulfonic acid. From this, it was shown that the polymer obtained by the above reaction is a random polymer and has a structure in which sulfonic acid groups are randomly arranged. The resulting polymer is referred to as “Pigment Dispersant-1”.

(Example 2: terminal group sulfonic acid type pigment dispersant)
A polymerization reactor similar to that used in Reference Example 1 was prepared, and 100 parts of PGMAc was charged into the polymerization vessel. In a separate container, 30 parts of MMA, 30 parts of BMA, 40 parts of 2EHMA, 3 parts of thioglycerol, and 0.5 part of AIBN were added and mixed to obtain a mixture. The obtained mixture was added to a polymerization vessel, heated to 80 ° C. with stirring under a nitrogen stream, and a polymerization reaction was carried out for 3 hours. Further, 133 parts of PGMAc and 0.1 part of AIBN were added to another container, mixed and homogenized to obtain a solution. The obtained solution was dropped into the polymerization vessel over 2 hours, and a polymerization reaction was performed for 5 hours to obtain a polymer solution. The resulting polymer solution had a solid content concentration of 30.1%, and the polymerization was almost complete. RI-Mn by GPC measurement was 5,700, and PDI was 1.89. In addition, it was hardly detected with the UV detector.

Next, after cooling the obtained polymer solution, 8.1 parts of SBA was added and dissolved by stirring. The reaction was carried out in the same manner as in Reference Example 1, and IR was used to confirm the disappearance of the peak derived from the sulfonic acid carboxylic anhydride of SBA and the decrease in the peak derived from the hydroxyl group of the polymer. In the GPC measurement, the same peak was confirmed in both the RI detector and the UV detector, the RI-Mn and the UV-Mn were both 5,900, and the PDI was 2.10. The solid content concentration was 30.9%. Moreover, when the acid value was measured similarly to Reference Example 1, it was 22.2 mgKOH / g. From the above, it was shown that the obtained polymer was a polymer having a structure having a sulfonic acid group at the terminal but not having a carboxyl group in the side chain. The resulting polymer is referred to as “Pigment Dispersant-2”.

(Example 3: End group sulfonic acid type pigment dispersant)
A polymerization reactor similar to that used in Reference Example 1 was prepared, and 100 parts of PGMAc was charged into the polymerization vessel. In a separate container, 23 parts of MMA, 27 parts of BMA, 35 parts of 2EHMA, 15 parts of methacrylic acid (MAA), 3 parts of thioglycerol, and 0.5 part of AIBN were added and mixed to obtain a mixture. The obtained mixture was added to a polymerization vessel, heated to 80 ° C. with stirring under a nitrogen stream, and a polymerization reaction was carried out for 3 hours. Further, 133 parts of PGMAc and 0.1 part of AIBN were added to another container, mixed and homogenized to obtain a solution. The obtained solution was dropped into the polymerization vessel over 2 hours, and a polymerization reaction was performed for 5 hours to obtain a polymer solution. The resulting polymer solution had a solid content concentration of 30.1%, and the polymerization was almost complete. RI-Mn by GPC measurement was 5,500, and PDI was 1.92. In addition, it was hardly detected with the UV detector. Moreover, it was 95.0 mgKOH / g when the acid value was measured.

Next, after cooling the obtained polymer solution, 8.1 parts of SBA was added and dissolved by stirring. The reaction was carried out in the same manner as in Reference Example 1, and IR was used to confirm the disappearance of the peak derived from the sulfonic acid carboxylic anhydride of SBA and the decrease in the peak derived from the hydroxyl group of the polymer. In the GPC measurement, an equivalent peak was confirmed in both the RI detector and the UV detector, RI-Mn and UV-Mn were both 5,600, and PDI was 2.21. The solid content concentration was 31.5%. Moreover, when the acid value was measured similarly to Reference Example 1, it was 109.9 mgKOH / g. From the above, the acid value derived from the carboxylic acid, which is theoretically calculated from the acid value of the polymer before reacting with SBA and the blending ratio of SBA, is about 88.1 mgKOH / g, and the acid value derived from the sulfonic acid group Was 21.8 mgKOH / g. From the above, the obtained polymer was shown to be a polymer having a structure having a sulfonic acid group at the terminal and a carboxyl group in the side chain. The resulting polymer is referred to as “Pigment Dispersant-3”.

( Reference Examples 6 and 7, Examples 8 to 11: pigment colorant composition)
(A) Pigment Refinement Treatment PR254, PG58, PY138, PY150, PB15: 6, and PV23 were prepared as color filter pigments and subjected to the refinement treatment by the method described below.
100 parts of each pigment, 400 parts of sodium chloride, and 130 parts of diethylene glycol were charged into a kneader equipped with a pressure lid. Premixing was performed until a uniformly moist mass was formed in the kneader. The pressure lid was closed and kneading and grinding were performed for 7 hours while pressing the contents at a pressure of 6 kg / cm ² . The obtained ground product was put into 3,000 parts of 2% sulfuric acid and stirred for 1 hour. After filtering to remove sodium chloride and diethylene glycol, each was sufficiently washed with water, dried and pulverized to obtain each pigment powder. The number average particle size of the obtained pigment powder was about 30 nm.

(B) Preparation of pigment colorant composition “Use materials” shown in Table 1 were blended in the amounts (parts) shown in Table 1, and stirred for 2 hours with a dissolver. After confirming that the lump of the pigment disappeared, the pigment was dispersed by using a horizontal medium disperser to prepare a pigment colorant composition. “Synergist 1”, “Synergist 2”, and “Synergist 3” in Table 1 are dye derivatives having an amino group, each represented by the following structure. The obtained pigment colorant composition was used as a “pigment dispersion” for each color of the pigment used.

  The “acrylic resin” in Table 1 has a monomer composition of BzMA / MAA = 80/20, RI-Mn by GPC measurement of 5,500, and PDI of 2.02. . This “acrylic resin” was used as a PGMAc solution (solid content concentration: 30%).

  Table 2 shows the measurement results of the number average particle diameter of the pigment contained in the obtained pigment dispersion. Table 2 shows the measurement results of the initial viscosity of the pigment dispersion and the viscosity after standing at 45 ° C. for 3 days (after storage).

  As shown in Table 2, it was found that the number average particle diameter of the pigment contained in the obtained pigment dispersion liquid of each color was 40 to 70 nm, and the refined pigment was sufficiently finely dispersed. did. In addition, any of the pigment dispersions has an initial viscosity of 15 mPa · s or less, and the viscosity after storage remains low as compared with the initial viscosity. Furthermore, when the initial viscosity and the viscosity after storage are compared, it is clear that the viscosity change is small. For this reason, the pigment dispersion was found to have sufficient stability.

Examples 12 to 14: Pigment colorant composition for color filter
(C) Preparation of pigment colorant composition for color filter The “materials used” shown in Table 3 are blended in the amounts (parts) shown in Table 3 and mixed thoroughly with a mixer, and the colorant pigment colorant for each color filter. A composition (color resist) was obtained. The obtained color resist was used as a “pigment ink” for each color.

  The “photosensitive acrylic resin varnish” in Table 3 is a varnish containing an acrylic resin obtained by reacting glycidyl methacrylate with a BzMA / MAA copolymer. Mn of this acrylic resin was 6,000, PDI was 2.38, and the acid value was 110 mgKOH / g. In Table 3, “TMPTA” represents trimethylolpropane triacrylate, “HEMPA” represents 2-hydroxyethyl-2-methylpropionic acid, and “DEAP” represents 2,2-diethoxyacetophenone.

(D) Preparation of red, green and blue glass substrates A glass substrate treated with a silane coupling agent was set on a spin coater. The red pigment ink-1 obtained in Example 12 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 a red glass substrate. Similarly, a green glass substrate and a blue glass substrate were produced using the green pigment ink-1 obtained in Example 13 and the blue pigment ink-1 obtained in Example 14, respectively.

  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 translucency and contrast ratio. From the above, it was found that the pigment inks obtained in Examples 12 to 14 are extremely useful as inks for forming the pixels of the color filter.

(Developability test)
A 0.1N tetramethylammonium hydroxide aqueous solution was spotted every 5 seconds on the color glass substrate produced using the pigment inks obtained in Examples 12 to 14, and “the exposed part of the coating film dissolved after several seconds. A development test was conducted. As a result, the coating film of the exposed portion dissolved after 10 seconds for the red glass substrate, 20 seconds for the green glass substrate, and 10 seconds for the blue glass substrate. In all cases, no film-like residue was generated, and good developability was exhibited. Furthermore, when the edge part (edge) of the coating film which remained without melt | dissolving was observed with the microscope, it has confirmed respectively that it was sharp. That is, if the pigment inks obtained in Examples 12 to 14 are used, the development time can be shortened and the productivity can be improved.

(Comparative Examples 1 and 2)
(1) Instead of “Pigment Dispersant-1”, a polyester-based dispersant having no sulfonic acid group (condensate of polyε-caprolactone and polyethyleneimine, starting with 12-hydroxystearic acid, Mn: 12,000, amine value: 12 mg KOH / g), and (2) Monosulfonated diketopyrrolopyrrole was used instead of “synergist 1” in the same manner as in Reference Example 6 described above. A comparative red pigment dispersion was prepared. In addition, (1) The above-described polyester-based dispersant was used instead of “Pigment Dispersant-3”, and (2) Monosulfonated PY-138 was used instead of “Synergist 2”. A comparative yellow pigment dispersion was prepared in the same manner as in Example 8 described above.

  Using these prepared comparative pigment dispersions, a comparative red pigment ink and a yellow pigment ink were prepared in the same manner as in Example 12, and a red glass for comparison was prepared using these pigment inks. A substrate and a yellow glass substrate were produced.

  When the above-described developability test was performed on the manufactured comparative red glass substrate and yellow glass substrate, it took 50 seconds to completely eliminate the exposed portion of the coating film. This is thought to be because the development time was long because the pigment dispersant cannot be alkali-developed. Further, in any glass substrate, the exposed portion of the coating film was detached in a film shape, and debris was generated. This is presumably because the pigment dispersant is not alkali-soluble. From the above, it was revealed that the coating film formed using the pigment dispersant of the present invention is excellent in developability.

  The pigment dispersant of the present invention has an excellent pigment dispersibility because it has a sulfonic acid group having an affinity for the pigment in the side chain or terminal. Further, by using such a pigment dispersant, a pigment colorant composition having low viscosity and excellent long-term storage stability can be prepared. And since the pigment ink obtained using this pigment colorant composition is excellent in coating properties and developability, the optical properties such as fineness, color density, light transmittance, and contrast are improved. It is useful as a material for producing a color filter. In addition, the pixel display device including the color filter manufactured in this way is excellent in image performance such as definition, color density, light transmission, and contrast.

Claims (8)

A hydroxyl group-containing acrylic polymer having one or more hydroxyl groups in the end the end of their, obtained by reacting 2-sulfobenzoic anhydride, consisting sulfonic acid group-containing acrylic polymer having a sulfonic acid group at an end thereof A pigment dispersant characterized by that.   The sulfonic acid group-containing acrylic polymer has a number average molecular weight of 2,000 to 20,000, an acid value of 10 to 250 mgKOH / g, and an acid value derived from the sulfonic acid group of 10 to 100 mgKOH / g. The pigment dispersant according to claim 1.   The pigment dispersant according to claim 1 or 2, wherein the sulfonic acid group-containing acrylic polymer contains 5 to 30% by mass of a structural unit derived from an addition polymerizable monomer having a carboxyl group. Before SL hydroxyl, pigment dispersing agent according to any one of claims 1 to 3 derived from azo radical polymerization initiator or a chain transfer agent having one or more hydroxyl groups having one or more hydroxyl groups. It is a manufacturing method of the pigment dispersant as described in any one of Claims 1-4 , Comprising:
A hydroxyl group-containing acrylic polymer having one or more hydroxyl groups in the end the end of their, by reacting 2-sulfobenzoic acid anhydride, the step of obtaining the sulfonic acid group-containing acrylic polymer having a sulfonic acid group at an end thereof A method for producing a pigment dispersant, comprising: A pigment colorant composition comprising the pigment dispersant according to any one of claims 1 to 4 and a pigment having a number average particle diameter of 10 to 150 nm. The pigment colorant composition according to claim 6 , further comprising a pigment derivative having a basic functional group. A pigment colorant composition for a color filter, which is obtained by using the pigment colorant composition according to claim 6 or 7 .