JP2006036830A - Pigment dispersant, and pigment composition and pigment dispersion using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pigment dispersant which can stably disperse various pigments in a vehicle and does not reduce physical properties of dried films, and to provide a stable pigment composition and a pigment dispersion excellent in non-aggregating properties and flowability and suitable for an offset ink, a rotogravure ink, a coating, an ink-jet ink and the like. <P>SOLUTION: The pigment dispersant comprises a vinyl polymer-grafted polyallylamine or a vinyl polymer-grafted polyvinylamine in which a vinyl polymer is chemically bonded with a polyallylamine or a polyvinylamine, respectively, wherein the vinyl polymer is obtained by copolymerizing an ethylenically unsaturated monomer having a functional group capable of reacting with an amino group and another ethylenically unsaturated monomer. The pigment composition comprises the pigment dispersant and a pigment. The pigment dispersion comprises the pigment dispersant and a pigment both dispersed in a liquid medium. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a pigment dispersant that can be used to disperse organic or inorganic powders in a liquid medium, and to a pigment composition and a pigment dispersion that are excellent in usability, in particular, non-aggregability and fluidity.

In general, when fine pigment particles are dispersed in vehicles such as offset inks, gravure inks and paints, it is difficult to obtain a stable dispersion, which causes various problems in manufacturing operations and the value of the resulting product. It has been known.
For example, dispersions containing pigments consisting of fine particles often exhibit high viscosity, making it difficult to remove and transport the product from the disperser, and if worse, cause gelation during storage. It can be difficult. Furthermore, regarding the coating film surface of the color-extended product, there may be a state defect such as a decrease in gloss and a leveling defect. In addition, when different types of pigments are used in combination, color unevenness and a marked decrease in coloring power may appear in the developed product due to phenomena such as color separation and sedimentation due to aggregation.

  In order to solve the above problems, various pigment dispersants and dispersion aids have been proposed and attempts have been made to improve pigment dispersion. For example, (a) a method using a nonionic, cationic or anionic surfactant, or a wetting agent such as a polyvalent carboxylic acid as a dispersing agent or dispersing aid, and (b) both affinity with a pigment affinity substance bound. A method of dispersing a pigment using a functional substance, (c) a method of reducing surface tension using a surfactant such as an alkyl silicone to prevent the pigment from floating, and (d) using a pigment derivative having a substituent. (E) a method in which a compound obtained by reacting a polyalkyleneimine and a polyester compound described in JP-A Nos. 54-37082 and 61-174939 is used as a dispersant. (F) Polyallylamine and polyester described in JP-A-08-38875, JP-A-09-169821, JP-A-2001-272524, etc. A method in which a compound obtained by reacting a tellurium compound, polyamide or the like is used as a dispersant, and (g) a compound in which polyethyleneimine and a vinyl polymer described in JP-A No. 63-12602 are used as a dispersant. Methods are known.

  However, it is difficult to obtain a stable state of the pigment particles with the dispersion aid or the pigment dispersant used in the methods (a) to (c). Further, the pigment derivative having a substituent used in the method (d) is colored because it has a pigment skeleton, and cannot be used as a general-purpose dispersant for various pigments. The dispersant used in the method (e) has a very narrow range of compatible resins, is difficult to increase in molecular weight because the side chain is polyester, and has a low molecular weight. It also has the disadvantage of lowering the physical properties. Further, even if the pigment dispersant used in the method (f) was used, a sufficient effect was not obtained.

Further, the pigment dispersant used in the method (g) is obtained by reacting a vinyl polymer having a functional group capable of reacting with an amino group at one or both ends with polyethyleneimine. As a method for introducing a functional group capable of reacting with an amino group, there are a method using a chain transfer agent when synthesizing a vinyl polymer and a method using a bifunctional compound. Since the reactivity with the amino group is low in the group, an unreacted vinyl polymer is produced, and when a bifunctional compound is used, a large amount of vinyl polymer that cannot react with the amino group is produced. Even in the method, a sufficient effect as a dispersant cannot be obtained.
JP-A 63-12602

  An object of this invention is to provide the pigment dispersant which can disperse | distribute various pigments stably to a vehicle, and does not reduce the physical property of a dry film. Another object of the present invention is to provide a stable pigment composition and a pigment dispersion which are suitable for offset ink, gravure ink, paint, inkjet ink, etc. and have excellent non-aggregation and fluidity.

The pigment dispersant in the present invention comprises a vinyl polymer obtained by copolymerizing an ethylenically unsaturated monomer having a functional group capable of reacting with an amino group and another ethylenically unsaturated monomer, and polyallylamine. It consists of a chemically bonded vinyl polymer grafted polyallylamine.
The pigment dispersant in the present invention includes a vinyl polymer obtained by copolymerizing an ethylenically unsaturated monomer having a functional group capable of reacting with an amino group and another ethylenically unsaturated monomer, and polyvinylamine. And a vinyl polymer grafted polyvinylamine chemically bonded to each other.
In addition, the pigment composition in the present invention includes the pigment dispersant and a pigment.
The pigment dispersion in the present invention is characterized in that the pigment dispersant and the pigment are dispersed in a liquid medium.

In the present invention, the pigment dispersant solvates with a solvent and chemically binds a vinyl polymer that interacts with a resin involved in film formation and a polyallylamine or polyvinylamine adsorbed on the pigment, thereby preventing the pigment dispersant. It has both excellent dispersibility of the pigment and good physical properties of the dry film.
By using the pigment dispersant of the present invention, it is possible to stably disperse a pigment even in a resin having poor pigment dispersibility. Therefore, a stable offset ink, gravure ink, paint, ink jet having excellent non-aggregability and fluidity. Ink etc. can be manufactured.

First, the pigment dispersant in the present invention will be described.
The pigment dispersant in the present invention includes a vinyl polymer obtained by copolymerizing an ethylenically unsaturated monomer having a functional group capable of reacting with an amino group and another ethylenically unsaturated monomer, and polyallylamine or polyvinyl. It consists of vinyl polymer grafted polyallylamine or vinyl polymer grafted polyvinylamine chemically bonded to amine, and vinyl polymer grafted polyallylamine and vinyl polymer grafted polyvinylamine are produced by the following two methods. be able to.
That is, the first method is that a vinyl copolymer formed by copolymerizing an ethylenically unsaturated monomer having a functional group capable of reacting with an amino group and another ethylenically unsaturated monomer; In this method, allylamine or polyvinylamine is reacted at 15 to 150 ° C. In the second method, an ethylenically unsaturated monomer having a functional group capable of reacting with an amino group is reacted with polyallylamine or polyvinylamine in advance, and then another ethylenically unsaturated monomer is reacted. This is a method of radical copolymerization.

  In these methods, an ethylenically unsaturated monomer having a functional group capable of reacting with an amino group is used to directly introduce a functional group capable of reacting with an amino group into a vinyl polymer, or directly with polyallylamine or polyvinylamine. An ethylenically unsaturated monomer having a functional group capable of reacting with an amino group is reacted. Therefore, when an ethylenically unsaturated monomer having a functional group capable of reacting with an amino group is copolymerized with another ethylenically unsaturated monomer, or an ethylenic group having a functional group capable of reacting with an amino group in advance. When reacting an unsaturated monomer with polyallylamine or polyvinylamine, there is no risk of a side reaction that loses a functional group capable of reacting with an amino group, and the desired vinyl polymer grafted polyallylamine or vinyl A coalescence graft polyvinylamine can be obtained easily.

  When producing vinyl polymer grafted polyallylamine and vinyl polymer grafted polyvinylamine by the above method, polyallylamine or polyvinylamine and an ethylenically unsaturated monomer having a functional group capable of reacting with the vinyl polymer or amino group. The body is made to react at a ratio of 0.01 to 1 functional group capable of reacting with the amino group in the vinyl polymer or monomer with respect to one amino group of polyallylamine or polyvinylamine. It is more preferable that the reaction is performed at a ratio of 0.1 to 0.85. When the ratio of the functional group capable of reacting with an amino group is less than 0.01, the resulting vinyl polymer graft polyallylamine or vinyl polymer graft polyvinylamine does not exhibit a sufficient dispersion effect, and when it exceeds 0.85 When the pigment dispersant is dissolved in the liquid medium, the viscosity increases, the amino group as the pigment adsorbing part is insufficient, and the resulting vinyl polymer grafted polyallylamine and vinyl polymer grafted polyvinylamine do not sufficiently adsorb to the pigment. Because.

Polyallylamine, which constitutes vinyl polymer grafted polyallylamine, is a linear cationic polymer that is water-soluble and has only a primary amino group in the side chain. Excellent. Polyallylamine can be obtained by, for example, producing polyallylamine hydrochloride from an allylamine hydrochloride aqueous solution by radical polymerization and then neutralizing and removing hydrochloric acid. For example, PAA-01, PAA-03 from Nitto Boseki Co., Ltd. , PAA-05, PAA-15, PAA-10C, and other polyallylamine series.
The number average molecular weight of the polyallylamine is preferably 300 to 100,000, and more preferably 1000 to 10,000. If the number average molecular weight of the polyallylamine is less than 300, it is difficult to obtain a good pigment dispersion effect. If the number average molecular weight exceeds 100000, the viscosity or gelation may occur during the reaction with the vinyl polymer. This is not preferable because the molecular weight of the whole agent becomes too large, and the dispersibility may be lowered.

The polyvinyl amine constituting the vinyl polymer grafted polyvinyl amine is a water-soluble linear cationic polymer having a primary amino group, and is excellent in adsorption to a pigment. Polyvinylamine can be obtained, for example, by decomposing polyvinylphthalimide with hydrazine, and is commercially available, for example, as PVAM from Mitsubishi Chemical Corporation.
The number average molecular weight of polyvinylamine is preferably 300 to 100,000, more preferably 1000 to 100,000. If the number average molecular weight of polyvinylamine is less than 300, it is difficult to obtain a good pigment dispersion effect. If it exceeds 100,000, viscosity may increase and gelation may occur during reaction with the vinyl polymer. This is not preferable because the molecular weight of the entire pigment dispersant becomes too large, which may cause a decrease in dispersibility.

The vinyl polymer grafted polyallylamine and the vinyl polymer constituting the vinyl polymer grafted polyvinylamine are composed of an ethylenically unsaturated monomer having a functional group capable of reacting with an amino group and another ethylenically unsaturated monomer. The product is obtained by radical polymerization with the body, and may be modified with, for example, urethane, polyester, polyether or the like.
The weight average molecular weight of the vinyl polymer is preferably 1000 to 100,000, and more preferably 5000 to 20000. If the weight average molecular weight of the vinyl polymer is less than 1000, the obtained vinyl polymer grafted polyallylamine and the vinyl polymer grafted polyvinylamine do not exhibit a sufficient dispersing effect. If the weight average molecular weight exceeds 100,000, the pigment dispersant is used as a liquid medium. In the case of dissolution, the viscosity becomes high, and there is a possibility of gelation during the reaction with polyallylamine or polyvinylamine.

As an ethylenically unsaturated monomer having a functional group capable of reacting with an amino group, an ethylenically unsaturated monomer having a functional group capable of reacting with an amino group such as a carboxyl group, an isocyanate group or an epoxy group should be used. Can do.
Examples of the ethylenically unsaturated monomer having a carboxyl group include acrylic acid, methacrylic acid, 2-carboxyethyl acrylate, phthalic acid monohydroxyethyl acrylate, ω-carboxy-polycaprolactone monoacrylate, maleic acid, itaconic acid, Examples include fumaric acid, glutagonic acid, tetrahydrophthalic acid, and vinyl acrylic acid. Examples of the ethylenically unsaturated monomer having an isocyanate group include 2-isocyanatoethyl methacrylate. Examples of the ethylenically unsaturated monomer having an epoxy group include epoxy (meth) acrylate.

式中、Ｂはイソシアネート基を有するエチレン性不飽和単量体の仕込み量（エチレン性不飽和単量体の全量を基準とする重量％）であり、Ｃはイソシアネート基を有するエチレン性不飽和単量体の分子量、Ｍはビニル重合体の重量平均分子量である。Ａの値が０．３未満であるとイソシアネート基を含まないビニル重合体が生成してしまう。また、４．０を超えるとビニル重合体に含まれるイソシアネート基が多くなり、ポリアリルアミンまたはポリビニルアミンとの反応時にゲル化を起こすため好ましくない。 Among them, an ethylenically unsaturated monomer having an isocyanate group has a very high reactivity between an isocyanate group and an amino group, and at the time of reaction between polyallylamine or polyvinylamine and a vinyl copolymer, polyallylamine or polyvinylamine. The reaction with the amino group therein can be carried out reliably at a low temperature, and a sufficient effect as a dispersant can be obtained.
When an ethylenically unsaturated monomer having an isocyanate group is used, the vinyl polymer is preferably a vinyl polymer having an A value of 0.3 to 4.0 calculated from the following formula.

In the formula, B is the amount of the ethylenically unsaturated monomer having an isocyanate group (% by weight based on the total amount of the ethylenically unsaturated monomer), and C is an ethylenically unsaturated monomer having an isocyanate group. The molecular weight of the polymer, M is the weight average molecular weight of the vinyl polymer. If the value of A is less than 0.3, a vinyl polymer containing no isocyanate group is produced. On the other hand, if it exceeds 4.0, the number of isocyanate groups contained in the vinyl polymer increases and gelation occurs during the reaction with polyallylamine or polyvinylamine.

Examples of the other ethylenically unsaturated monomers include ethylenically unsaturated monomers other than the ethylenically unsaturated monomers having a functional group capable of reacting with the amino group, such as (meth) acrylic acid esters. , Aromatic vinyls, vinyl acetate and the like can be used. The other monomer may have a functional group that does not react with an amino group such as a hydroxyl group.
Examples of (meth) acrylic acid esters having a hydroxyl group include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, and 2-hydroxybutyl (meth) acrylate. , 3-hydroxybutyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, polycaprolactone-modified hydroxyethyl (meth) acrylate (repetition number of caprolactone = 1-6), glycerin (meth) acrylate, polyethylene glycol mono (meta ) Acrylate, polypropylene glycol mono (meth) acrylate, and the like.

Other (meth) acrylic acid esters include, for example, methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, (meth) acrylic acid-2-ethylhexyl, (meth) Octyl acrylate, stearyl (meth) acrylate, cyclohexyl (meth) acrylate, benzyl (meth) acrylate, urethane (meth) acrylate, methoxypolyethylene glycol mono (meth) acrylate, allyloxypolyethylene glycol mono (meth) acrylate, Nonylphenoxy polyethylene glycol monoacrylate, phenol ethylene oxide modified acrylate, nonyl phenol ethylene oxide modified acrylate, bisphenol F ethylene oxide modified diacrylate, and the like.
Examples of aromatic vinyls include styrene and α-methylstyrene.
These monomers are commercially available, for example, as a Blemmer series from Nippon Oil & Fat Co., Ltd. and as an Aronix series from Toa Gosei Co., Ltd.

Said ethylenically unsaturated monomer can be used individually or in combination of 2 or more types.
Copolymerization of an ethylenically unsaturated monomer having a functional group capable of reacting with an amino group and another ethylenically unsaturated monomer is carried out in the presence of an initiator under an inert gas stream at 50 to 150 ° C. For 2 to 10 hours. The polymerization can be carried out in the presence of a solvent.
Examples of the initiator include organic peroxides such as benzoyl peroxide, cumene hydroperoxide, t-butyl hydroperoxide, and t-butyl peroxycarbonate, and azo such as 2,2′-azobisisobutyronitrile. Compounds and the like. The initiator is preferably used in an amount of 0.5 to 25 parts by weight with respect to a total of 100 parts by weight of the ethylenically unsaturated monomer.

Examples of the solvent include acetic acid ester organic solvents such as ethyl cellosolve acetate and propylene glycol monomethyl ether acetate, ketone organic solvents such as cyclohexanone and methyl isobutyl ketone, aromatic hydrocarbon organic solvents such as xylene and ethylbenzene, and ethyl alcohol. Alcohol organic solvents such as isopropyl alcohol and n-propyl alcohol, ether organic solvents such as mono- or dialkyl ethers of ethylene glycol or diethylene glycol, water, and the like can be used.
The pigment dispersant may be used as a solution or suspension of various solvents used at the time of polymerization of the monomer, or may be diluted with a solvent other than the solvent used at the time of synthesis.

Next, the pigment composition in the present invention will be described.
The pigment composition in the present invention is a pigment composition containing the pigment dispersant and the pigment.
As the pigment contained in the pigment composition, all organic pigments, inorganic pigments and carbon black which can be generally used for ink or paint can be used.
The content of the pigment dispersant in the pigment composition is preferably 1 to 30% by weight based on the weight of the pigment. When the content of the pigment dispersant is less than 1% by weight, a sufficient dispersion effect cannot be obtained, and when it exceeds 30% by weight, the effect of only adding is not obtained, which is economically disadvantageous. This is not preferable because it may adversely affect the physical properties of the coating film.

  Examples of the organic pigment include diketopyrrolopyrrole pigments, azo pigments such as azo, disazo, and polyazo, phthalocyanine pigments such as copper phthalocyanine, halogenated copper phthalocyanine, and metal-free phthalocyanine, aminoanthraquinone, diaminodianthraquinone, anthra Anthraquinone pigments such as pyrimidine, flavantron, anthanthrone, indanthrone, pyranthrone, violanthrone, quinacridone pigment, dioxazine pigment, perinone pigment, perylene pigment, thioindigo pigment, isoindoline pigment, isoindolinone pigment Quinophthalone pigments, selenium pigments, metal complex pigments, and the like.

Examples of inorganic pigments include titanium oxide, zinc white, zinc sulfide, white lead, calcium carbonate, precipitated barium sulfate, white carbon, alumina white, kaolin clay, talc, bentonite, black iron oxide, cadmium red, red rose, molybdenum Red, molybdate orange, chrome vermilion, yellow lead, cadmium yellow, yellow iron oxide, titanium yellow, chromium oxide, viridian, titanium cobalt green, cobalt green, cobalt chrome green, Victoria green, ultramarine, bituminous, cobalt blue, cerulean Examples include blue, cobalt silica blue, cobalt zinc silica blue, cobalt zinc silica blue, manganese violet, and cobalt violet.
Examples of carbon black include acetylene black, channel black, and furnace black.

Finally, the pigment dispersion in the present invention will be described.
The pigment dispersion in the present invention is one in which the pigment dispersant and the pigment are dispersed in a liquid medium, and an acidic functional group-containing organic dye derivative may be further dispersed in the liquid medium.
The pigment dispersion is generally prepared by mixing a pigment, the pigment dispersant of the present invention, a liquid medium, and, if necessary, an organic functional group-containing organic dye derivative, a binder, an additive, and other pigment dispersants. It can manufacture using the disperser or mixer used for manufacture. Examples of the disperser and the mixer include a horizontal sand mill, a vertical sand mill, an annular bead mill, an attritor, a high speed mixer, a homomixer, a ball mill, a roll mill, a stone mill, and an ultrasonic disperser.

The pigment, the pigment dispersant of the present invention, the acidic functional group-containing organic dye derivative, the binder, the additive, the liquid medium, etc. may be dispersed after mixing all the components. Group-containing organic dye derivative etc. and pigment alone, pigment dispersant and pigment alone, or pigment dispersant and acidic functional group-containing organic dye derivative alone are dispersed, and then another component is added in order and dispersed again. Good. In addition, before dispersing with a disperser, pre-dispersion with a kneader mixer such as a kneader or three rolls, solid dispersion with a two roll mill or the like, or a pigment dispersant and acidic functional group-containing organic dye derivative to the pigment, etc. You may perform the process of.
As the liquid medium, the organic solvent exemplified as the solvent that can be used at the time of polymerization of the monomer and water can be used.

  Examples of the binder include petroleum resin, casein, shellac, rosin-modified maleic resin, rosin-modified phenolic resin, nitrocellulose, cellulose acetate butyrate, cyclized rubber, chlorinated rubber, oxidized rubber, hydrochloric acid rubber, phenolic resin, and alkyd resin. , Polyester resin, unsaturated polyester resin, amino resin, epoxy resin, vinyl resin, vinyl chloride, vinyl chloride-vinyl acetate copolymer, acrylic resin, methacrylic resin, polyurethane resin, silicone resin, fluorine resin, drying oil, synthetic drying Examples thereof include oil, styrene-modified maleic acid, polyamide resin, chlorinated polypropylene, butyral resin, and vinylidene chloride resin.

  An acidic functional group-containing organic dye derivative is a compound in which an acidic functional group is introduced into a generally known organic dye. Organic dyes include, for example, azo dyes, phthalocyanine dyes, anthraquinone dyes, quinacridone dyes, dioxazine dyes, anthrapyrimidine dyes, ansanthrone dyes, indanthrone dyes, flavanthrone dyes, perinone dyes, perylene dyes, and thioindico dyes. However, it may be one that is hardly colored like anthraquinone.

  Examples of the acidic functional group in the organic functional group-containing organic dye derivative include a sulfonic acid group, a carboxyl group, and a phosphoric acid group, and a sulfonic acid group is most preferable. The acidic functional group may be previously introduced into the coupler component or diazo component of the azo pigment, or may be introduced later into the organic dye by some reaction. For example, as a method for introducing a sulfonic acid group into an organic dye, there is a method of reacting an organic dye with a sulfonating agent such as sulfuric acid, fuming sulfuric acid or chlorosulfuric acid, which is disclosed in JP-A-5-98200. . In addition, as disclosed in JP-A-8-209043, there is a method in which a sulfonic acid is introduced after reacting an organic dye with some compound as a linking substance.

The acidic functional group-containing organic dye derivative may be a metal salt, an organic amine salt, or a quaternary ammonium salt. Examples of metal salts include salts of potassium, sodium, calcium, aluminum, strontium, barium and the like. Examples of organic amine salts include primary amine salts such as octylamine and dodecylamine, secondary amine salts such as dioleylamine and distearylamine, and tertiary amine salts such as dimethyllaurylamine and dimethylstearylamine. Examples of the quaternary ammonium salt include trimethylammonium and dimethyldistearylammonium.
The pigment dispersion of the present invention can be used for non-aqueous or water-based paints, gravure inks, offset inks, inkjet inks, plastic coloring, and the like.

EXAMPLES Hereinafter, although this invention is demonstrated concretely based on an Example, this invention is not limited to these. In the examples, “parts” and “%” represent “parts by weight” and “% by weight”, respectively. The molecular weight of the copolymer is a polystyrene-equivalent weight average molecular weight measured by GPC (gel permeation chromatography).
[Vinyl polymer production example 1]
A separable four-necked flask was equipped with a thermometer, a condenser tube, a nitrogen gas inlet tube, and a stirrer, charged with 285 parts of cyclohexanone, heated to 90 ° C. and purged with nitrogen in the reaction vessel, and then n-butyl methacrylate 135 from the dropping tube. .9 parts, methyl methacrylate 22.7 parts, 2-isocyanatoethyl methacrylate 1.4 parts, 2,2'-azobisisobutyronitrile 3.2 parts, and cyclohexanone 39 parts are added dropwise over 2 hours. did. Two hours after the completion of the dropwise addition, a solution obtained by dissolving 0.6 part of 2,2′-azobisisobutyronitrile in cyclohexanone was added, and the reaction was further continued for 1 hour. A combined (1) solution was obtained. The weight average molecular weight of the vinyl polymer (1) was 15000, and the value of A was 0.88.

[Vinyl polymer production example 2]
A separable four-necked flask was equipped with a thermometer, a condenser tube, a nitrogen gas inlet tube, and a stirrer, charged with 285 parts of toluene, heated to 90 ° C. and purged with nitrogen in the reaction vessel, and then n-butyl methacrylate 136 from the dropping tube. A mixed solution of 0.5 part, 22.6 parts of methyl methacrylate, 0.8 part of methacrylic acid, 3.2 parts of 2,2′-azobisisobutyronitrile and 39 parts of toluene was added dropwise over 2 hours. Two hours after the completion of the dropwise addition, a solution obtained by dissolving 0.45 part of 2,2′-azobisisobutyronitrile in toluene was added, and the reaction was further continued for 1 hour. A combined (2) solution was obtained. The weight average molecular weight of the vinyl polymer (2) was 14,000.

[Vinyl polymer production example 3]
A separable four-necked flask is equipped with a thermometer, a cooling tube, a nitrogen gas inlet tube, and a stirrer and charged with 295 parts of cyclohexanone. The temperature is raised to 90 ° C., and the inside of the reaction vessel is purged with nitrogen. 137.1 parts, methyl methacrylate 22.9 parts, and 2,2′-azobisisobutyronitrile 3.2 parts were added dropwise over 2 hours. Two hours after the completion of the dropwise addition, a solution obtained by dissolving 0.6 part of 2,2′-azobisisobutyronitrile in cyclohexanone was added, and the reaction was further continued for 1 hour. A combined (3) solution was obtained. The weight average molecular weight of the vinyl polymer (3) was 18000.

[Example 1]
An autoclave equipped with a thermometer, a stirrer, a cooling separation tube, and a dropping tube was charged with 0.5 part of a polyallylamine 20% aqueous solution (“PAA-03” manufactured by Nitto Boseki Co., Ltd., number average molecular weight 3000) at 80 ° C. The system was evacuated to remove moisture, cooled to room temperature, and 0.57 parts of cyclohexanone was added.
After purging the inside of the reaction vessel with nitrogen, 53.4 parts of the vinyl polymer (1) solution obtained in Production Example 1 from the dropping tube (corresponding to 0.5 isocyanate for one amino group of polyallylamine), cyclohexanone 37.4 parts were added dropwise over 30 minutes. Further, the reaction was continued at 25 ° C. for 1 hour to obtain a pigment dispersant (1) solution having a solid content of 15%.

[Example 2]
An autoclave equipped with a thermometer, a stirrer, a cooling separation tube, and a dropping tube was charged with 1.0 part of a polyallylamine 10% aqueous solution (“PAA-10C” manufactured by Nitto Boseki Co., Ltd., number average molecular weight 15000) at 80 ° C. The system was evacuated to remove moisture, cooled to room temperature, and 0.57 parts of cyclohexanone was added.
After purging the inside of the reaction vessel with nitrogen, 53.4 parts of the vinyl polymer (1) solution obtained in Production Example 1 from the dropping tube (corresponding to 0.5 isocyanate groups relative to 1 amino group of polyallylamine), 37.4 parts of cyclohexanone was added dropwise over 30 minutes. Further, the reaction was continued at 25 ° C. for 1 hour to obtain a pigment dispersant (2) solution having a solid content of 15%.

[Example 3]
An autoclave equipped with a thermometer, a stirrer, a cooling separation tube, and a dropping tube was charged with 0.01 part of a 20% polyallylamine aqueous solution (“PAA-03” manufactured by Nitto Boseki Co., Ltd., number average molecular weight 3000) at 80 ° C. The system was evacuated to remove moisture, cooled to room temperature, and 0.57 parts of cyclohexanone was added.
After purging the inside of the reaction vessel with nitrogen, 53.4 parts of the vinyl polymer (1) solution obtained in Production Example 1 from the dropping tube (corresponding to 0.01 isocyanate group for one amino group of polyallylamine), 37.4 parts of cyclohexanone was added dropwise over 30 minutes. Further, the reaction was continued at 25 ° C. for 1 hour to obtain a pigment dispersant (3) solution having a solid content of 15%.

[Example 4]
An autoclave equipped with a thermometer, a stirrer, a cooling separation tube, and a dropping tube was charged with 0.9 part of a 20% polyallylamine aqueous solution (“PAA-03” manufactured by Nitto Boseki Co., Ltd., number average molecular weight 3000) at 80 ° C. The system was evacuated to remove moisture, cooled to room temperature, and 0.57 parts of cyclohexanone was added.
After purging the inside of the reaction vessel with nitrogen, 53.4 parts of the vinyl polymer (1) solution obtained in Production Example 1 from the dropping tube (corresponding to 0.9 isocyanate groups relative to one amino group of polyallylamine), 37.4 parts of cyclohexanone was added dropwise over 30 minutes. The reaction was further continued at 25 ° C. for 1 hour to obtain a pigment dispersant (4) solution having a solid content of 15%.

[Example 5]
An autoclave equipped with a thermometer, a stirrer, a cooling separation tube, and a dropping tube was charged with 0.5 parts of 20% polyallylamine aqueous solution (“PAA-03” manufactured by Nitto Boseki Co., Ltd., weight average molecular weight 3000) at 80 ° C. The system was evacuated to remove moisture, cooled to room temperature, and 0.57 parts of cyclohexanone was added.
After purging the inside of the reaction vessel with nitrogen, 53.4 parts of the vinyl polymer (2) solution obtained in Production Example 1 from the dropping tube (corresponding to 0.5 isocyanate groups relative to 1 amino group of polyallylamine), 37.4 parts of cyclohexanone was added dropwise over 30 minutes. Further, the reaction was continued at 25 ° C. for 1 hour to obtain a pigment dispersant (5) solution having a solid content of 15%.

[Example 6]
An autoclave equipped with a thermometer, a stirrer, a cooling separation tube, and a dropping tube was charged with 0.6 parts of a 12% aqueous solution of polyvinylamine ("PVAM-0595B" manufactured by Mitsubishi Chemical Corporation, number average molecular weight 70000) at 80 ° C. The system was evacuated to remove moisture, cooled to room temperature, and 0.5 parts of cyclohexanone was added.
After substituting the inside of the reaction vessel with nitrogen, 54.5 parts of the vinyl polymer (1) solution obtained in Production Example 1 from the dropping tube (0.5 isocyanate group for one primary amino group of polyvinylamine) ), 38.2 parts of cyclohexanone was added dropwise over 30 minutes. Further, the reaction was continued at 25 ° C. for 1 hour to obtain a pigment dispersant (6) solution having a solid content of 15%.

[Example 7]
An autoclave equipped with a thermometer, a stirrer, a cooling separation tube, and a dropping tube was charged with 1.1 parts of a 12% aqueous solution of polyvinylamine ("PVAM-0595B" manufactured by Mitsubishi Chemical Corporation, number average molecular weight 70000) at 80 ° C. The system was evacuated to remove moisture, cooled to room temperature, and 0.5 parts of cyclohexanone was added.
After purging the inside of the reaction vessel with nitrogen, 54.5 parts of the vinyl polymer (1) solution obtained in Production Example 1 from the dropping tube (corresponding to 0.9 isocyanate group relative to 1 amino group of polyvinylamine), 38.2 parts of cyclohexanone was added dropwise over 30 minutes. Further, the reaction was continued at 25 ° C. for 1 hour to obtain a pigment dispersant (7) solution having a solid content of 15%.

[Comparative Example 1]
An autoclave equipped with a thermometer, a stirrer, a cooling separation tube, and a dropping tube was charged with 0.5 part of a polyallylamine 20% aqueous solution (“PAA-03” manufactured by Nitto Boseki Co., Ltd., number average molecular weight 3000) at 80 ° C. The system was evacuated to remove moisture, cooled to room temperature, and 0.57 parts of cyclohexanone was added.
After purging the inside of the reaction vessel with nitrogen, 53.4 parts of the vinyl polymer (3) solution obtained in Production Example 3 (mixing ratio corresponding to 0.5 isocyanate group to 1 amino group of polyallylamine) Were mixed dropwise to obtain a pigment dispersant (8) solution.

[Comparative Example 2]
An autoclave equipped with a thermometer, a stirrer, a cooling separation tube, and a dropping tube was charged with 0.6 parts of a 12% aqueous solution of polyvinylamine ("PVAM-0595B" manufactured by Mitsubishi Chemical Corporation, number average molecular weight 70000) at 80 ° C. The system was evacuated to remove moisture, cooled to room temperature, and 0.5 parts of cyclohexanone was added.
After substituting the inside of the reaction vessel with nitrogen, 54.5 parts of the vinyl polymer (3) solution obtained in Production Example 3 (mixing ratio corresponding to 0.5 isocyanate group to 1 amino group of polyvinylamine) Were dropped and mixed to obtain a pigment dispersant (9).

[Example 8]
An autoclave equipped with a thermometer, a stirrer, a cooling separation tube, and a dropping tube was charged with 80 parts of a polyallylamine 20% aqueous solution (“PAA-03” manufactured by Nitto Boseki Co., Ltd., number average molecular weight 3000) and heated to 80 ° C. Then, the system was evacuated to remove moisture, cooled to room temperature, and 91 parts of cyclohexanone was added.
After the inside of the reaction vessel was purged with nitrogen, 50 parts of 2-isocyanatoethyl methacrylate (corresponding to 0.5 isocyanate groups with respect to one amino group of polyallylamine) was dropped from the dropping tube over 30 minutes. By continuing reaction for 1 hour after completion | finish of dripping, the compound (1) solution of 40% of solid content was obtained. Next, a separable four-necked flask was equipped with a thermometer, a cooling tube, a nitrogen gas introduction tube, and a stirring device, charged with 285 parts of cyclohexanone, heated to 90 ° C., and purged with nitrogen in the reaction vessel. A mixed solution of 135.9 parts of butyl methacrylate, 22.7 parts of methyl methacrylate, 3 parts of the compound (1) solution, 3.2 parts of 2,2′-azobisisobutyronitrile and 39 parts of cyclohexanone is dropped over 2 hours. did. Two hours after the completion of the dropwise addition, a solution in which 0.6 part of 2,2′-azobisisobutyronitrile is dissolved in cyclohexanone is added, and the reaction is continued for another hour, whereby a pigment dispersion with a solid content of 30% is added. An agent (10) solution was obtained. The weight average molecular weight of the pigment dispersant was 16000.

  Using the pigment dispersant solutions obtained in the Examples and Comparative Examples, paints having the compositions shown in Table 1 were prepared. CI Pigment Blue 15: 3 (“Lionol Blue FG-7351” manufactured by Toyo Ink Co., Ltd.) is used as the pigment, phthalocyanine monosulfonic acid is used as the derivative (organic dye derivative), and cyclohexanone is used as the solvent. It was. Dispersion was performed with a paint conditioner using zirconia beads. However, when the pigment dispersion solution obtained in the comparative example was used, the pigment could not be dispersed in the liquid medium, the pigments aggregated, and no paint was obtained. The gloss value when the obtained paint was applied to a film was measured. Further, the viscosity of the paint was measured with a rheometer, and the TI value was calculated by dividing the viscosity at a rotation speed of 10 rpm by the viscosity at a rotation speed of 100 rpm. The results are shown in Table 1. The higher the gloss value, the better, the lower the viscosity, the better, and the closer the TI value to 1, the better.

Claims (7)

  Vinyl in which a vinyl polymer obtained by copolymerizing an ethylenically unsaturated monomer having a functional group capable of reacting with an amino group and other ethylenically unsaturated monomers and polyallylamine are chemically bonded A pigment dispersant comprising a polymer-grafted polyallylamine.   Vinyl in which a vinyl polymer obtained by copolymerizing an ethylenically unsaturated monomer having a functional group capable of reacting with an amino group and other ethylenically unsaturated monomers and polyvinylamine are chemically bonded A pigment dispersant comprising a polymer-grafted polyvinylamine.   The pigment dispersant according to claim 1 or 2, wherein the functional group capable of reacting with an amino group is an isocyanate group. The pigment dispersant according to claim 3, wherein the vinyl polymer is a vinyl polymer having an A value of 0.3 to 4.0 calculated from the following formula.

B: Charge amount of the ethylenically unsaturated monomer having an isocyanate group (% by weight based on the total amount of the ethylenically unsaturated monomer)
C: Molecular weight of ethylenically unsaturated monomer having isocyanate group M: Weight average molecular weight of vinyl polymer   A pigment composition comprising the pigment dispersant according to any one of claims 1 to 4 and a pigment.   A pigment dispersion, wherein the pigment dispersant and the pigment according to claim 1 are dispersed in a liquid medium.   The pigment dispersion according to claim 6, further comprising an acidic functional group-containing organic dye derivative dispersed in a liquid medium.