JP4470012B2 - Pigment dispersion for inkjet ink and method for producing the same - Google Patents

Description

  The present invention relates to a polymer composition for inkjet ink, a pigment dispersion for inkjet ink, and a method for producing the same. In particular, the present invention relates to a polymer composition for ink-jet ink capable of obtaining an image having high gloss, a pigment dispersion for ink-jet ink, and a method for producing the same.

  The ink jet recording method is a method for recording images, characters, and the like by causing ink droplets to fly and adhere to recording paper, and is capable of high-speed recording, is inexpensive, and has many In recent years, it has been widely used by general users such as offices and home users because it can be easily colored.

  Examples of the ink used in the ink jet recording method include dye ink and pigment ink. A characteristic of the pigment ink is that the weather resistance of the printed matter is much higher than that of the dye ink. In addition, the color density of the printed matter is higher than that of the dye ink, and the occurrence of bleeding is small.

  Therefore, printed photographs using digital cameras are also popularized at home, and the use of dye inks with weak weather resistance has been shifting from pigment inks with weather resistance that will not change color over a long period of time. .

  However, since the pigment ink is insoluble in the medium, it has been difficult to keep the pigment ink stable for a long time. Therefore, even if photographic paper is used, an image having gloss similar to that of a silver salt photograph cannot be obtained.

  The present invention has been made in view of the above-described situation, and an image having high gloss can be obtained. Moreover, the polymer composition for ink-jet ink and the pigment dispersion for ink-jet ink, which are excellent in stability, dispersibility, and weather resistance, and It is in providing the manufacturing method.

  As a result of various studies on compositions that improve the gloss of an image using pigment ink, the present inventors have found that a composition having a specific structure, type, acid value, weight average molecular weight, etc. has a high gloss. Cyclohexyl acrylate (A1) and / or benzyl acrylate (A2) consisting of 8% by weight to 98% by weight and methacrylic acid consisting of 1% by weight to 31% by weight. The composition comprising, as a main component, an acrylic acid (C) composed of 1% by weight to 25% by weight of an acid (B) has a dispersibility of the pigment due to a cyclohexyl group and / or a benzyl group. It has been found that when it is used in an ink jet ink, an image having high gloss can be formed because the property of being easily improved is exhibited. It has also been found that when such a composition having a specific acid value is used, an excellent stability, dispersibility and weather resistance can be obtained, and an image having high gloss can be obtained. I came up with the idea that I could do it.

  That is, the present invention relates to cyclohexyl acrylate (A1) and / or benzyl acrylate (A2) composed of 8% by weight to 98% by weight, methacrylic acid (B) composed of 1% by weight to 31% by weight, and 1% by weight. % Acrylic acid (C) composed of 25% by weight or more and polymerized as a main component, and further has an acid value of 10 mgKOH / g or more and 200 mgKOH / g or less.

  According to the polymer composition for an ink-jet ink of the present invention, when used in an ink-jet ink, an image having high gloss can be obtained, and the stability, dispersibility, and weather resistance are excellent.

  Therefore, when the acid value is less than 10 mgKOH / g, pigment dispersion becomes difficult and stability is deteriorated, and when it exceeds 200 mgKOH / g, the hydrophilicity becomes strong and the weather resistance and the OD value (optical density) for plain paper are increased. Decreases.

  In the present invention, it is preferable that the (meth) acrylate (D1) having a long-chain alkyl group is polymerized at 20% by weight or less.

  In the present invention, it is further preferable that the (meth) acrylate (D2) having an amino group is polymerized at 20% by weight or less.

  Further, in the present invention, it is preferable that the (meth) acrylate (D3) having a hydroxyl group is polymerized at 20% by weight or less.

  In the present invention, the weight average molecular weight is preferably 5000 or more and 150,000 or less.

  If the weight average molecular weight is less than 5,000, the fixability as an inkjet ink may be deteriorated. On the other hand, if it exceeds 150,000, the viscosity as an inkjet ink may be increased, and the stability may be further reduced. is there.

  Furthermore, this invention is also the pigment dispersion for inkjet inks containing the said polymer composition for inkjet inks, a pigment, and an aqueous medium.

  According to the polymer composition for inkjet ink of the present invention, an image having high gloss can be obtained, and the stability, dispersibility, and weather resistance are excellent.

  In the present invention, the average primary particle diameter of the pigment is preferably 20 nm or more and 70 nm or less.

  The pigment dispersion for ink-jet ink obtained by using the pigment finely treated in this way is more finely divided than that using a general commercial pigment, so that the gloss, gloss change and Fixability can be improved.

  A method for producing a pigment dispersion for ink-jet ink comprising the polymer composition for ink-jet ink of the present invention and a pigment, comprising 10 parts by weight or more of an alcohol solvent or a ketone solvent with respect to 100 parts by weight of the pigment It is preferable to include a dispersion step of adding and dispersing so as to be 280 parts by weight or less.

  According to the method for producing a pigment dispersion for ink-jet ink of the present invention, the pigment dispersion for ink-jet ink is further finely divided, and the gloss, gloss change and fixability of the printed material can be further improved.

  As used herein, “a pigment dispersion for inkjet ink” refers to a pigment that has been appropriately treated with a polymer composition for inkjet ink, and is finely divided by a disperser or the like and has a high concentration (for example, 10 ˜20% by weight). The “inkjet ink” is a pigment dispersion for inkjet ink that is adjusted to an optimum pigment concentration by adding various additives and / or aqueous media so as to be suitable for inkjet printer printing and the like. .

  The polymer composition for ink-jet ink and the pigment dispersion for ink-jet ink according to the present invention have the above-described configuration, provide an image having high gloss, and are excellent in stability, dispersibility, and weather resistance. .

  Therefore, when the acid value is less than 10 mgKOH / g, pigment dispersion becomes difficult and stability is deteriorated, and when it exceeds 200 mgKOH / g, the hydrophilicity becomes strong and the weather resistance and the OD value (optical density) for plain paper are increased. Decreases.

  The present invention is described in detail below.

  The polymer composition for inkjet ink of the present invention comprises cyclohexyl acrylate (A1) and / or benzyl acrylate (A2) composed of 8% by weight or more and 98% by weight or less, and methacrylic acid (B ) And 1% by weight to 25% by weight of acrylic acid (C) are polymerized to have a main component and further have an acid value of 10 mgKOH / g to 200 mgKOH / g.

  The content of the cyclohexyl acrylate (A1) and / or benzyl acrylate (A2) is 8% by weight or more and 98% by weight or less, but the types and combinations of pigments and aqueous media used in the pigment dispersion for inkjet inks. It may be set as appropriate depending on, and the like, preferably 30% to 95% by weight, more preferably 50% to 90% by weight.

  The content of the methacrylic acid (B) is 1% by weight or more and 31% by weight or less, and may be appropriately set depending on the type or combination of the pigment, aqueous medium, etc. used in the pigment dispersion for inkjet ink, Preferably they are 3 to 25 weight%, More preferably, they are 5 to 20 weight%.

  The content of the acrylic acid (C) is 1% by weight or more and 25% by weight or less, and may be appropriately set depending on the type or combination of the pigment used in the inkjet ink pigment dispersion, the aqueous medium, and the like. Preferably they are 2 to 23 weight%, More preferably, they are 3 to 20 weight%.

  The acid value is from 10 mgKOH / g to 200 mgKOH / g, preferably from 20 mgKOH / g to 150 mgKOH / g, more preferably from 30 mgKOH / g to 150 mgKOH / g. When the acid value is less than 10 mgKOH / g, pigment dispersion becomes difficult and stability is deteriorated. On the other hand, when it exceeds 200 mgKOH / g, the hydrophilicity becomes strong and the weather resistance and the OD value (optical density) for plain paper are lowered. To do.

  In the present invention, it is preferable that the (meth) acrylate (D1) having a long-chain alkyl group is polymerized at 20% by weight or less.

  The (meth) acrylate (D1) having a long-chain alkyl group is not particularly limited, and examples include stearyl acrylate, stearyl methacrylate, lauryl acrylate, lauryl methacrylate, and n-dodecyl methacrylate. These may be used alone or in combination of two or more.

  As said long chain alkyl group, a C10-C18 linear alkyl group etc. are mentioned, for example. Preferably, it is a C12-18 alkyl group.

  The content of the (meth) acrylate (D1) having a long-chain alkyl group is 20% by weight or less, and may be appropriately set depending on the type and combination of the pigment and the aqueous medium used in the pigment dispersion for inkjet ink. Preferably, it is 1 to 20% by weight, more preferably 5 to 20% by weight.

  In the present invention, it is further preferable that the (meth) acrylate (D2) having an amino group is polymerized at 20% by weight or less.

  The (meth) acrylate (D2) having an amino group is not particularly limited, and 2- (dimethylamino) ethyl methacrylate, 2- (diethylamino) ethyl methacrylate, 2- (dimethylamino) ethyl acrylate, morpholinoethyl acrylate, etc. Is mentioned. These may be used alone or in combination of two or more.

  The content of the amino group-containing (meth) acrylate (D2) is 20% by weight or less, and may be appropriately set depending on the type and combination of pigments and aqueous media used in the pigment dispersion for inkjet ink. The content is preferably 1% by weight or more and 20% by weight or less, more preferably 3% by weight or more and 20% by weight or less.

  Further, in the present invention, it is preferable that the (meth) acrylate (D3) having a hydroxyl group is polymerized at 20% by weight or less.

  The (meth) acrylate (D3) having a hydroxyl group is not particularly limited, and examples thereof include hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate, and hydroxypropyl methacrylate. These may be used alone or in combination of two or more.

  The content of the (meth) acrylate (D3) having a hydroxyl group is 20% by weight or less, and may be appropriately set depending on the type or combination of the pigment and the aqueous medium used in the pigment dispersion for inkjet ink, Preferably they are 1 weight% or more and 20 weight% or less, More preferably, they are 3 weight% or more and 20 weight% or less.

  In the present invention, the weight average molecular weight is preferably 5000 or more and 150,000 or less.

  The weight average molecular weight is preferably 5000 or more and 150,000 or less, more preferably 5000 or more and 100,000 or less. If the weight average molecular weight is less than 5,000, the fixability as an ink-jet ink may be deteriorated. On the other hand, if it exceeds 150,000, the viscosity as an ink-jet ink is increased and the stability may be further lowered.

  The molecular weight distribution (weight average molecular weight / number average molecular weight) is preferably 2 or more and 8 or less. For example, those having a weight average molecular weight of 5000 and those having a weight average molecular weight of 100,000 may be used in combination. The above may be used in combination.

  And cyclohexyl acrylate (A1), benzyl acrylate (A2), methacrylic acid (B), acrylic acid (C), (meth) acrylate (D1) having a long chain alkyl group, (meth) acrylate having an amino group (D2) ) And / or the method for polymerizing the (meth) acrylate (D3) having a hydroxyl group is not particularly limited, and may be a conventionally known ordinary method.

  Furthermore, as a polymerization method, for example, as a method for adding a monomer at the time of polymerization, it may be charged all at the beginning of the reaction, or at least one may be added to the reaction system continuously or intermittently. The polymerization is preferably performed in the presence of a radical polymerization initiator and / or a catalyst.

  As the solvent used in the polymerization, an alcohol solvent, a ketone solvent, an ether solvent, or a glycol ether solvent is preferable.

  Examples of the alcohol solvent include methanol, ethanol, isopropanol, 1-butanol, tertiary butanol, isobutanol, diacetone alcohol, and the like.

  Examples of the ketone solvent include acetone, methyl ethyl ketone, diethyl ketone, methyl isobutyl ketone, and cyclohexanone.

  Examples of the ether solvent include dibutyl ether, tetrahydrofuran, dioxane and the like.

  Examples of the glycol ethers include ethylene glycol monomethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol diethyl ether, and butyl cellosolve.

  Examples of the radical polymerization initiator include organic peroxides such as t-butyl peroxy (2-ethylhexanoate), di-t-butyl peroxide, t-butyl peroxybenzoate, and t-butyl peroxy octoate. 2,2′-azobisisobutyronitrile, 2,2′-azobis (2,4-dimethylvaleronitrile), dimethyl-2,2′-azobisbutyrate, 2,2′-azobis (2- Azo compounds such as methylbutyronitrile are preferred.

  As the usage-amount of the said radical polymerization initiator, 0.01 mol% or more and 5 mol% or less are preferable with respect to the monomer used in the case of superposition | polymerization.

  The polymerization temperature is not particularly limited, but is usually in the range of 30 to 100 ° C, and preferably in the range of 40 to 90 ° C. When the polymerization temperature is too low, the polymerization rate of the monomer may decrease.

  Furthermore, this invention is also the pigment dispersion for inkjet inks containing the said polymer composition for inkjet inks, a pigment, and an aqueous medium.

  The pigment is not particularly limited as long as it is normally used, but the average primary particle diameter of the pigment is preferably 20 nm or more and 70 nm or less, and more preferably 20 nm or more and 60 nm or less. .

  The pigment can be finely divided (from 20 nm to 70 nm) by a conventional method, but a method using sulfuric acid or a method by mechanical attrition may be mentioned, and the pigment dispersion for inkjet ink should be adversely affected. There is no particular limitation.

  As used herein, “primary particle diameter” refers to the average diameter of the smallest unit that can be clearly separated from others. In general, it is difficult to disperse large agglomerated particles completely to the primary particle size. Therefore, the “particle size” is after the dispersion step, but several primary particles are aggregated into agglomerated particles. This is the average diameter of what you have. In addition, the diameter means an intermediate value between the maximum diameter and the minimum diameter when it is not a true sphere.

  Examples of yellow color pigments include CI No. PY-55, PY-74, PY-79, PY-93, PY-110, PY-120, PY-128, PY-138, PY-139, and PY-150. , PY-151, PY-155, PY-156, PY-175, and the like.

  Examples of magenta color pigments include C.I.No.PR-122, PR-122 / PR-254 solid solutions, PV-19, and the like.

  Examples of cyan pigments include C.I.No. PB-15: 3, PB-15: 4, PB-15: 1, and aluminum phthalocyanine.

  Carbon black is generally used as the black pigment, but titanium black and the like can also be mentioned.

  Among these pigments, they may be used alone or in combination of two or more depending on the color tone and light resistance.

  The average particle diameter of the pigment is preferably 150 nm or less, and more preferably 100 nm or less. When the average particle diameter exceeds 150 nm, the ejection properties from the nozzles are deteriorated, nozzle clogging occurs, and it may be difficult to obtain an image having high gloss.

  As said aqueous medium, pure water and ultrapure water, such as ion-exchange water, ultrafiltration water, reverse osmosis water, distilled water, are preferable, for example. Furthermore, it is preferable to use water sterilized by ultraviolet treatment, hydrogen peroxide treatment or the like for the purpose of preventing the generation of mold, bacteria and the like.

  The amount of the ink-jet ink polymer composition used may be appropriately set depending on the type and combination of the pigment and aqueous medium used in the ink-jet ink pigment dispersion, and is preferably 20 wt. % To 150% by weight, more preferably 30% to 100% by weight. If the amount used is less than 20% by weight, the dispersibility and stability may deteriorate and gloss may be insufficient. If the amount used exceeds 150% by weight, the ink-jet ink is thickened or economically appropriate. There is a risk of not being able to say.

  In the present invention, a dispersant, a surface tension adjusting agent or a penetrating agent (surfactant), a wetting and drying preventing agent, an antiseptic, a bactericidal agent, a pH adjusting agent, a rust preventing agent, a moisturizing agent and other additives are added as necessary. An agent may be used. These may be used alone or in combination of two or more.

  Any known dispersant may be used as long as it does not adversely affect the pigment dispersion for injecting ink to be prepared. Examples of the dispersant include styrene-acrylic acid copolymer, styrene-maleic acid copolymer, styrene-maleic acid-modified copolymer, styrene-methacrylic acid copolymer, styrene-methacrylic acid-acrylic acid copolymer, Copolymer resins such as styrene-acrylic acid-acrylic acid ester copolymer, styrene-methacrylic acid-acrylic acid ester copolymer, polyoxyethylene glycol acrylate-acrylic acid copolymer, vinyl acetate-maleic acid copolymer; Anionic surface activity such as fatty acid salt, alkyl sulfate ester salt, alkyl allyl sulfonate salt, alkyl naphthalene sulfonate salt, naphthalene sulfonate formaldehyde condensate, polyoxyethylene alkyl phosphate ester salt, polyoxyethylene alkyl ether sulfate salt Agent; polyoxyethylene Nonionic surfactants such as alkyl ethers, polyoxyethylene alkyl allyl ethers, sorbitan fatty acid esters, glycerin fatty acid esters, polyoxyethylene fatty acid esters, polyoxyethylene sorbitol fatty acid esters, acetylene glycol ethylene oxide adducts; alkyl betaines, Examples include amphoteric surfactants such as alkylamine oxide. These dispersants may be used alone or in combination of two or more.

  As the surface tension adjusting agent or penetrating agent, known ones can be used as long as they do not adversely affect the prepared pigment dispersion for jet ink. As the surface tension adjusting agent, any of anionic, cationic and nonionic surfactants can be used. Specifically, examples of the anionic surfactant include polyethylene glycol alkyl ether sulfate, higher alcohol sulfate, naphthalene sulfonic acid formalin condensate, and the like. Examples thereof include vinyl pyridine derivatives and poly 4-vinyl pyridine derivatives. Nonionic surfactants include polyoxyethylene alkyl ether, polyoxyethylene alkyl ether sulfate, polyoxyalkyl phenyl ether, polyoxyethylene alkyl ester. And polyoxyethylene sorbitan monoalkyl ether, acetylene glycol ethylene oxaside adduct, polyoxyethylene alkylamine and the like.

  As the wet-drying inhibitor, the following water-soluble organic solvents may be mixed in order to adjust the physical properties of the pigment dispersion for inkjet ink to a desired value and to prevent drying of the inkjet ink in the nozzle holes. For example, C1-C4 alkyl alcohols such as methanol, ethanol, isopropanol, 1-butanol and 2-butanol; ketones or ketone alcohols such as acetone and acetone alcohol; ethers such as tetrahydrofuran and dioxane; ethylene glycol, Propylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, glycerin, 1,3-butylene glycol, ethylene glycol monomethyl ether, ethylene glycol dimethyl ether, ethylene glycol monobutyl ether, diethylene glycol diethyl ether, diethylene glycol mono-n-methyl ether, diethylene glycol mono- n-ethyl ether, diethylene glycol mono-n-butyl ether Polyhydric alcohols such as ter, triethylene glycol monomethyl ether, triethylene glycol mono-n-butyl ether, 1,2-hexanediol and ethers thereof; acetates; N-methyl-2-pyrrolidone, 2-pyrrolidone, 1,3 -Nitrogen-containing compounds such as dimethylimidazolinone, dimethylformamide, triethanolamine and the like. These water-soluble organic solvents may be used alone or in combination of two or more.

  As the preservative and bactericidal agent, known ones may be used as long as they do not adversely affect the pigment dispersion for inkjet ink to be prepared. For example, sodium dehydroacetate, sodium sorbate, sodium 2-pyridinethiol-1-oxide, sodium benzoate, sodium pentachlorophenol, 1,2-benzisothiazolin-3-one, Nn-butylbenzisothiazoline-3- ON, dithio-2,2-bis (benzmethylamide), polyhexamethylene biguanide and the like. Among these, since the pH of the inkjet ink is easy to control, sodium dehydroacetate, sodium sorbate, 2-pyridinethiol-1-oxide sodium, sodium benzoate, sodium pentachlorophenol, 1,2-benzisothiazoline-3 -On, Nn-butylbenzisothiazolin-3-one is preferred.

  As the pH adjuster, a known agent may be used as long as it can be controlled to a desired pH without adversely affecting the prepared pigment dispersion for inkjet ink. For example, organic amines such as methylamine and ethylamine; lower alkanolamines such as monoethanolamine, diethanolamine and triethanolamine; inorganic bases such as ammonium hydroxide, sodium hydroxide and potassium hydroxide Is mentioned.

  As the rust preventive agent, known ones may be used as long as they do not adversely affect the pigment dispersion for ink jet ink to be prepared. Examples thereof include acidic sulfite, sodium thiosulfate, ammonium thioglycolate, diisopropylammonium nitrite, pentaerythritol tetranitrate, dicyclohexylammonium nitrite and the like.

  Next, as a method for producing the pigment dispersion for inkjet ink of the present invention, for example, the polymer composition for inkjet ink of the present invention, an aqueous medium, alkali such as sodium hydroxide is emulsified by high-speed stirring, and further the pigment (Including paste pigment) and the like, and a method of strongly dispersing with a disper or the like. Further, if necessary, a method of dispersing with a three-roll mill or the like, dispersing the obtained pigment slurry to a predetermined particle size with a high-pressure disperser or the like, and then removing the organic solvent or the like from the obtained pigment dispersion Etc. may be performed.

  At this time, it is a manufacturing method of the pigment dispersion for inkjet inks which contains the polymer composition for inkjet inks of this invention, and a pigment, Comprising: 10 weight part of alcohol solvent or ketone solvent with respect to 100 weight part of pigments It is preferable to include a dispersion step of additionally dispersing so that the amount is 280 parts by weight or less. More preferably, the alcohol-based solvent or the ketone-based solvent is used with respect to 100 parts by weight of the pigment from the viewpoint that the finer the pigment dispersion for ink-jet ink further progresses and the gloss, gloss change and fixability of the printed material are further improved. 20 parts by weight or more and 250 parts by weight or less, and particularly preferably, the alcohol solvent or the ketone solvent is added by 40 parts by weight or more and 200 parts by weight or less with respect to 100 parts by weight of the pigment. .

  For example, in the dispersion step, the alcohol-based solvent or the solvent for the ink-jet ink containing the polymer composition for ink-jet ink of the present invention and the alcohol-based solvent or ketone-based solvent is added to 100 parts by weight of the pigment added later. An alcohol solvent or a ketone solvent is added so that the ketone solvent is 10 parts by weight or more and 280 parts by weight or less, and then a pigment is added and dispersed.

  Further, it is preferable to include a dispersion step of dispersing the aqueous medium in an amount of 180 parts by weight or more and 1100 parts by weight or less with respect to 100 parts by weight of the pigment.

  And as needed, you may remove a coarse particle from the pigment dispersion for inkjet inks by centrifugation, filter filtration, etc.

  The high-pressure disperser is not particularly limited, but is a microfluidizer (Microfluidics), an optimizer (Sugino Machine), a wet jet mill (Genus), a nanomizer (Nanomizer), a homogenizer (SMD, Gorin). Company).

  The pressure at the time of dispersing with the high-pressure disperser may be any as long as it can reach the desired pigment particle diameter, but is preferably 100 MPa or more. If the desired pigment particle diameter cannot be reached, the dispersion may be carried out by increasing the number of dispersions or increasing the pressure.

  The vacuum distillation method is not limited, and examples thereof include a batch type vacuum distillation method.

  Further, in the method for producing a pigment dispersion for ink-jet ink of the present invention, an alkali solution is added to the polymer composition for ink-jet ink that has been polymerized and heated, and then the solvent is removed, and ion-exchanged water or the like is used. A substituted polymer composition solution for an inkjet ink may be used.

  Furthermore, the solvent is removed from the ink-jet ink polymer composition solution, which has been polymerized, by distillation under reduced pressure, the solid matter of the ink-jet ink polymer composition obtained is crushed, and ion-exchanged water, an alkali solution, etc. are added and heated You may use the polymer composition solution for inkjet inks obtained by melt | dissolving. In this case, thereafter, it is not necessary to remove the organic solvent and the like from the obtained pigment dispersion.

  Examples of the alkali used in the alkali solution include tertiary amines and alkanolamines such as trimethylamine, triethylamine, triethanolamine and dimethylethanolamine; inorganic bases such as sodium hydroxide, potassium hydroxide and lithium hydroxide. Etc. The degree of neutralization is not particularly limited, but the pH of the resulting ink-jet ink polymer composition solution is preferably 6-10.

  According to the pigment dispersion for inkjet ink of the present invention, an image having high gloss can be obtained, and the stability, dispersibility, and weather resistance are excellent.

(Example)
The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples. Note that “%” means “% by weight” unless otherwise specified.

  The inside of a 2000 ml separable flask equipped with a stirrer, reflux tube, temperature sensor, and dropping funnel was sufficiently purged with nitrogen, and then 200.0 parts by weight of diethylene glycol monomethyl ether was placed in the separable flask and stirred at 80 ° C. The temperature rose.

  Next, 200.0 parts by weight of diethylene glycol monomethyl ether, 483.0 parts by weight of cyclohexyl acrylate (hereinafter referred to as “CHA”), 66.6 parts by weight of methacrylic acid (hereinafter referred to as “MAA”), acrylic acid in a dropping funnel 50.4 parts by weight (hereinafter referred to as “AA”) and 4.8 parts by weight of t-butylperoxy (2-ethylhexanoate) (hereinafter referred to as “BPEH”) are added, and the mixture is kept at 80 ° C. for 4 hours. And dropped into a separable flask.

  After completion of dropping, the mixture was kept at 80 ° C. for 1 hour, 0.8 part by weight of BPEH was added, and the reaction was further carried out at 80 ° C. for 1 hour.

  After completing the aging, diethylene glycol monomethyl ether was removed by distillation under reduced pressure. Thereafter, 600.0 parts by weight of methyl ethyl ketone (hereinafter referred to as “MEK”) was added to obtain a polymer composition solution for inkjet ink having a resin solid content of 50%. A portion of the thus obtained ink-jet ink polymer composition solution was taken and dried for 1 hour in a high-temperature dryer at 105 ° C., and then the solid acid value of the ink-jet ink polymer composition obtained was It was 130 mgKOH / g, and the weight average molecular weight was 34000.

  Next, 6.0 parts by weight of a 30% aqueous sodium hydroxide solution is added to 120.0 parts by weight of the polymer composition solution for inkjet ink, and the mixture is stirred with a high-speed disper for 5 minutes. Further, Cyanine Blue having a pigment concentration of 25% by weight. Add 480.0 parts by weight of G-500 pure-A (PB-15: 1 and ion-exchanged water; average primary particle diameter of pigment: 70 nm; manufactured by Sanyo Dyeing Co., Ltd.), stir with a high-speed disper for 1 hour, and pigment dispersion slurry Got.

  The pigment dispersion slurry was continuously dispersed 20 times at a pressure of 200 MPa with a high pressure homogenizer (Microfluidizer, manufactured by Mizuho Kogyo Co., Ltd.) to obtain a pigment dispersion.

  Further, MEK is removed from the pigment dispersion by distillation under reduced pressure, centrifuged at 5000 rpm for 30 minutes with a centrifuge (05P-21, manufactured by Hitachi, Ltd.), and then ion-exchanged water is added so that the pigment concentration becomes 15% by weight. The pigment dispersion for inkjet ink was added and adjusted. Then, after pressure filtration using a 2.5 μm membrane filter (manufactured by Advantech Co., Ltd.), an ink-jet ink according to Example 1 is obtained which is adjusted by adding ion-exchanged water so that the pigment concentration becomes 4% by weight. It was.

An inkjet ink according to Example 2 was obtained in the same manner as Example 1 except that 483.0 parts by weight of benzyl acrylate (hereinafter referred to as “BZA”) was used instead of 483.0 parts by weight of CHA. . Moreover, after taking a part of polymer composition solution for inkjet inks, and drying for 1 hour with a high-temperature dryer of 105 degreeC, the acid value of the solid substance of the obtained polymer composition for inkjet inks is 130 mgKOH / g. The weight average molecular weight was 32,000.

An inkjet ink according to Example 3 was obtained in the same manner as in Example 1 except that 17.2 parts by weight of BPEH was used instead of 4.8 parts by weight of BPEH. Moreover, after taking a part of polymer composition solution for inkjet inks, and drying for 1 hour with a high-temperature dryer of 105 degreeC, the acid value of the solid substance of the obtained polymer composition for inkjet inks is 130 mgKOH / g. The weight average molecular weight was 8,000.

An inkjet ink according to Example 4 was obtained in the same manner as Example 2 except that 17.2 parts by weight of BPEH was used instead of 4.8 parts by weight of BPEH. Moreover, after taking a part of polymer composition solution for inkjet inks, and drying for 1 hour with a high-temperature dryer of 105 degreeC, the acid value of the solid substance of the obtained polymer composition for inkjet inks is 130 mgKOH / g. The weight average molecular weight was 9000.

Instead of 480.0 parts by weight of Cyanine G-500 pure-A having a pigment concentration of 25% by weight, Fast Yellow 7413-A having a pigment concentration of 25% by weight (PY-74 and ion-exchanged water; average primary particle diameter of the pigment of 80 nm; Sanyo Dye Co., Ltd.) was used (480.0 parts by weight), and instead of adding ion-exchanged water to a pigment concentration of 4% by weight, ion-exchanged water was added to give a pigment concentration of 6% by weight. Except for the above, the same procedure as in Example 1 was performed to obtain an inkjet ink according to Example 5.

Instead of 480.0 parts by weight of Cyanine G-500 pure-A having a pigment concentration of 25% by weight, 480.0 parts by weight of Fast Yellow 7413-A having a pigment concentration of 25% by weight was used. Thus, instead of adding ion-exchanged water, an ink-jet ink according to Example 6 was obtained in the same manner as Example 4 except that ion-exchanged water was added so that the pigment concentration was 6% by weight.

Instead of 480.0 parts by weight of Cyanine G-500 pure-A having a pigment concentration of 25% by weight, Pigment Violet GC227-A having a pigment concentration of 25% by weight (PV-19 and ion-exchanged water; average primary particle diameter of pigment: 80 nm; Sanyo Dye Co., Ltd.) was used (480.0 parts by weight), and instead of adding ion-exchanged water to a pigment concentration of 4% by weight, ion-exchanged water was added to give a pigment concentration of 6% by weight. Except for this, the same procedure as in Example 1 was performed to obtain an inkjet ink according to Example 7.

Instead of 480.0 parts by weight of Cyanine G-500 pure-A having a pigment concentration of 25% by weight, 480.0 parts by weight of Pigment Violet GC227-A having a pigment concentration of 25% by weight was used, and the pigment concentration was further increased to 4% by weight. Thus, instead of adding ion-exchanged water, an ink-jet ink according to Example 8 was obtained in the same manner as in Example 4 except that ion-exchanged water was added so that the pigment concentration was 6% by weight.

Instead of 200.0 parts by weight of diethylene glycol monomethyl ether, 483.0 parts by weight of CHA, 66.6 parts by weight of MAA, 50.4 parts by weight of AA and 4.8 parts by weight of BPEH, 200.0 parts by weight of diethylene glycol monomethyl ether, 540.6 parts by weight of CHA Ink jet ink according to Example 9 was obtained in the same manner as in Example 1 except that 32.4 parts by weight of MAA, 27.0 parts by weight of AA and 4.8 parts by weight of BPEH were used. Moreover, after taking a part of polymer composition solution for inkjet inks and drying for 1 hour with a 105 degreeC high temperature drier, the acid value of the solid substance of the obtained polymer composition for inkjet inks is 65 mgKOH / g. The weight average molecular weight was 33,000.

Instead of 200.0 parts by weight of diethylene glycol monomethyl ether, 483.0 parts by weight of CHA, 66.6 parts by weight of MAA, 50.4 parts by weight of AA and 4.8 parts by weight of BPEH, 200.0 parts by weight of diethylene glycol monomethyl ether and 363.0 parts by weight of CHA MAA 66.6 parts by weight, AA 50.4 parts by weight, stearyl methacrylate (hereinafter referred to as “SMA”) 120.0 parts by weight and BPEH 5.4 parts by weight. An inkjet ink according to Example 10 was obtained in the same manner as in Example 1 except that it was performed at 85 ° C. instead of being performed at 80 ° C. Moreover, after taking a part of polymer composition solution for inkjet inks, and drying for 1 hour with a high-temperature dryer of 105 degreeC, the acid value of the solid substance of the obtained polymer composition for inkjet inks is 130 mgKOH / g. The weight average molecular weight was 33,000.

  The inside of a 2000 ml separable flask equipped with a stirrer, a reflux tube, a temperature sensor, and a dropping funnel was sufficiently purged with nitrogen, and then 200.0 parts by weight of MEK was placed in the separable flask and heated to 80 ° C. while stirring. .

  Subsequently, MEK 200.0 parts by weight, CHA 520.8 parts by weight, MAA 36.6 parts by weight, AA 30.6 parts by weight, 2- (diethylamino) ethyl methacrylate (hereinafter referred to as “DEAEMA”) 12.0 parts by weight in the dropping funnel And 4.8 parts by weight of 2,2′-azobisisobutylnitrile (hereinafter referred to as “AIBN”) were added and dropped into a separable flask at 80 ° C. over 4 hours.

  After completion of dropping, the mixture was kept at 80 ° C. for 1 hour, then 0.8 parts by weight of AIBN was added, and the reaction was further carried out at 80 ° C. for 1 hour.

  After ripening was completed, it was cooled to 25 ° C. Then, 200.0 parts by weight of MEK was added to obtain a polymer composition solution for inkjet ink having a resin solid content of 50%. A portion of the thus obtained ink-jet ink polymer composition solution was taken and dried for 1 hour in a high-temperature dryer at 105 ° C., and then the solid acid value of the ink-jet ink polymer composition obtained was It was 80 mgKOH / g and the weight average molecular weight was 33000.

  Next, 6.0 parts by weight of a 30% aqueous sodium hydroxide solution is added to 120.0 parts by weight of the polymer composition solution for inkjet ink, and the mixture is stirred with a high-speed disper for 5 minutes. Further, Cyanine Blue having a pigment concentration of 25% by weight. 480.0 parts by weight of G-500 pure-A was added and stirred for 1 hour with a high speed disper to obtain a pigment dispersion slurry.

  Then, the pigment dispersion slurry was continuously dispersed 20 times at a pressure of 200 MPa with a high-pressure homogenizer (microfluidizer) to obtain a pigment dispersion.

  Further, MEK was removed from the pigment dispersion by distillation under reduced pressure, centrifuged at 5000 rpm for 30 minutes with a centrifugal separator (05P-21), and then ion-exchanged water was added so that the pigment concentration was 15% by weight. A pigment dispersion was prepared. Then, after pressure filtration using a 2.5 μm membrane filter (manufactured by Advantech Co., Ltd.), an ink-jet ink according to Example 11 is obtained which is adjusted by adding ion-exchanged water so that the pigment concentration becomes 4% by weight. It was.

In place of 200.0 parts by weight of MEK, 520.8 parts by weight of CHA, 36.6 parts by weight of MAA, 30.6 parts by weight of AA, 12.0 parts by weight of DEAEMA and 4.8 parts by weight of AIBN, 200.0 parts by weight of MEK and 502.8 parts by weight of CHA Example 3 except that 36.6 parts by weight of MAA, 30.6 parts by weight of AA, 30.0 parts by weight of 2-hydroxyethyl methacrylate (hereinafter referred to as “HEMA”) and 4.8 parts by weight of AIBN were used. And an inkjet ink according to Example 12 was obtained. Moreover, after taking a part of polymer composition solution for inkjet inks and drying with a high-temperature dryer of 105 ° C. for 1 hour, the acid value of the solid matter of the obtained polymer composition for inkjet ink is 80 mgKOH / g. The weight average molecular weight was 32,000.

  The inside of a 2000 ml separable flask equipped with a stirrer, reflux tube, temperature sensor, and dropping funnel was sufficiently purged with nitrogen, and then 200.0 parts by weight of diethylene glycol monomethyl ether was placed in the separable flask and stirred at 80 ° C. The temperature rose.

  Next, 200.0 parts by weight of diethylene glycol monomethyl ether, 483.0 parts by weight of CHA, 66.6 parts by weight of MAA, 50.4 parts by weight of AA, and 4.8 parts by weight of BPEH were placed in the dropping funnel, and a separable flask over 4 hours at 80 ° C. It was dripped in.

  After completion of dropping, the mixture was kept at 80 ° C. for 1 hour, 0.8 part by weight of BPEH was added, and the reaction was further carried out at 80 ° C. for 1 hour.

  After completing the aging, diethylene glycol monomethyl ether was removed by distillation under reduced pressure. Thereafter, 600.0 parts by weight of MEK was added to obtain a polymer composition solution for inkjet ink having a resin solid content of 50%. The polymer composition solution for ink-jet ink thus obtained was taken and dried for 1 hour with a high-temperature drier at 105 ° C., and then a solid material of the polymer composition for ink-jet ink was obtained.

  Next, in a 2000 ml separable flask equipped with a stirrer, a reflux tube, a temperature sensor, and a dropping funnel, 300.0 parts by weight of a pulverized ink-jet ink polymer composition and 727.0 wt. Part was stirred.

  Next, 173.0 parts by weight of a 30% aqueous sodium hydroxide solution was placed in the dropping funnel and dropped into the separable flask over 5 minutes.

  After completion of the dropwise addition, the temperature was raised to 90 ° C., held at 90 ° C. for 2 hours, and then cooled to room temperature to obtain a polymer composition solution for inkjet ink. The polymer composition solution for ink-jet ink thus obtained had a solid content concentration of 29.0% and a pH of 9.2.

  480.0 parts by weight of Cyanine G-500 pure-A having a pigment concentration of 25% by weight was added to 206.0 parts by weight of the polymer composition solution for inkjet ink, and the mixture was stirred with a high-speed disper for 1 hour to obtain a pigment dispersion slurry.

  Then, the pigment dispersion slurry was continuously dispersed 20 times at a pressure of 200 MPa with a high-pressure homogenizer (microfluidizer) to obtain a pigment dispersion.

  Furthermore, after centrifuging at 5000 rpm for 30 minutes with a centrifuge (05P-21), ion-exchanged water was added so that the pigment concentration was 15% by weight to prepare a pigment dispersion for inkjet ink. Then, after pressure filtration using a 2.5 μm membrane filter (manufactured by Advantech), ion-exchanged water was added so as to obtain a pigment concentration of 4% by weight, whereby an inkjet ink according to Example 13 was obtained. It was.

  The inside of a 2000 ml separable flask equipped with a stirrer, reflux tube, temperature sensor, and dropping funnel was sufficiently purged with nitrogen, and then 200.0 parts by weight of diethylene glycol monomethyl ether was placed in the separable flask and stirred at 80 ° C. The temperature rose.

  Next, 200.0 parts by weight of diethylene glycol monomethyl ether, 483.0 parts by weight of BZA, 66.6 parts by weight of MAA, 50.4 parts by weight of AA and 4.8 parts by weight of BPEH were placed in the dropping funnel, and a separable flask was put at 80 ° C. for 4 hours. It was dripped in.

  After completion of dropping, the mixture was kept at 80 ° C. for 1 hour, 0.8 part by weight of BPEH was added, and the reaction was further carried out at 80 ° C. for 1 hour.

  After completing the aging, diethylene glycol monomethyl ether was removed by distillation under reduced pressure. Thereafter, 600.0 parts by weight of MEK was added to obtain a polymer composition solution for inkjet ink having a resin solid content of 50%.

  Next, in a 3000 ml separable flask equipped with a stirrer, a reflux tube, a temperature sensor, and a dropping funnel, the polymer composition solution for inkjet ink was placed, and 1454.0 parts by weight of ion-exchanged water and 30 parts were added to the dropping funnel. 346.0 parts by weight of an aqueous sodium hydroxide solution was added and dropped into a separable flask over 20 minutes.

  After completion of the dropwise addition, the temperature was raised to 80 ° C. and held at 80 ° C. for 30 minutes, and then MEK was removed by distillation under reduced pressure to obtain a polymer composition solution for inkjet ink. The polymer composition solution for ink-jet ink thus obtained had a solid content concentration of 30.5% and a pH of 9.1. Moreover, after taking a part of polymer composition solution for inkjet inks, and drying for 1 hour with a high-temperature dryer of 105 degreeC, the acid value of the solid substance of the obtained polymer composition for inkjet inks is 130 mgKOH / g. The weight average molecular weight was 32,000.

  480.0 parts by weight of Cyanine G-500 pure-A having a pigment concentration of 25% by weight was added to 197.0 parts by weight of the polymer composition solution for inkjet ink, and the mixture was stirred with a high-speed disper for 1 hour to obtain a pigment dispersion slurry.

  Then, the pigment dispersion slurry was continuously dispersed 20 times at a pressure of 200 MPa with a high-pressure homogenizer (microfluidizer) to obtain a pigment dispersion.

  Furthermore, after centrifuging at 5000 rpm for 30 minutes with a centrifuge (05P-21), ion-exchanged water was added so that the pigment concentration was 15% by weight to prepare a pigment dispersion for inkjet ink. Then, after pressure filtration using a 2.5 μm membrane filter (manufactured by Advantech Co., Ltd.), an ink-jet ink according to Example 14 is obtained which is adjusted by adding ion-exchanged water so that the pigment concentration becomes 4% by weight. It was.

<Comparative Example 1>
Ink jet according to Comparative Example 1 except that 483.0 parts by weight of 2-ethylhexyl acrylate (hereinafter referred to as “EHA”) was used instead of 483.0 parts by weight of CHA. Ink was obtained. Moreover, after taking a part of polymer composition solution for inkjet inks, and drying for 1 hour with a high-temperature dryer of 105 degreeC, the acid value of the solid substance of the obtained polymer composition for inkjet inks is 130 mgKOH / g. The weight average molecular weight was 38000.

<Comparative example 2>
An inkjet ink according to Comparative Example 2 was obtained in the same manner as in Example 3 except that 483.0 parts by weight of EHA was used instead of 483.0 parts by weight of CHA. Moreover, after taking a part of polymer composition solution for inkjet inks, and drying for 1 hour with a high-temperature dryer of 105 degreeC, the acid value of the solid substance of the obtained polymer composition for inkjet inks is 130 mgKOH / g. The weight average molecular weight was 10,000.

<Comparative Example 3>
An inkjet ink according to Comparative Example 3 was obtained in the same manner as in Example 1 except that 483.0 parts by weight of lauryl acrylate (hereinafter referred to as “LA”) was used instead of 483.0 parts by weight of CHA. . Moreover, after taking a part of polymer composition solution for inkjet inks, and drying for 1 hour with a high-temperature dryer of 105 degreeC, the acid value of the solid substance of the obtained polymer composition for inkjet inks is 130 mgKOH / g. The weight average molecular weight was 38000.

<Comparative example 4>
An inkjet ink according to Comparative Example 4 was obtained in the same manner as in Example 3 except that 483.0 parts by weight of LA was used instead of 483.0 parts by weight of CHA. Moreover, after taking a part of polymer composition solution for inkjet inks, and drying for 1 hour with a high-temperature dryer of 105 degreeC, the acid value of the solid substance of the obtained polymer composition for inkjet inks is 130 mgKOH / g. The weight average molecular weight was 10,000.

<Comparative Example 5>
Instead of 480.0 parts by weight of Cyanine G-500 pure-A having a pigment concentration of 25% by weight, 480.0 parts by weight of Fast Yellow 7413-A having a pigment concentration of 25% by weight was used. Thus, instead of adding ion-exchanged water, an ink-jet ink according to Comparative Example 5 was obtained in the same manner as Comparative Example 4 except that ion-exchanged water was added so that the pigment concentration was 6% by weight.

<Comparative Example 6>
Instead of 480.0 parts by weight of Cyanine G-500 pure-A having a pigment concentration of 25% by weight, 480.0 parts by weight of Pigment Violet GC227-A having a pigment concentration of 25% by weight was used, and the pigment concentration was further increased to 4% by weight. Thus, instead of adding ion-exchanged water, an ink-jet ink according to Comparative Example 6 was obtained in the same manner as Comparative Example 4 except that ion-exchanged water was added so that the pigment concentration was 6% by weight.

  The polymer composition solution for inkjet inks having a resin solid content of 50% used in Example 2 was used, and then 6.0 parts by weight of 30% aqueous sodium hydroxide solution with respect to 120.0 parts by weight of the polymer composition solution for inkjet inks. Added, and stirred for 5 minutes with a high-speed disper, and further pigment paste (average pigment primary particle size 45 nm) 480.0 parts by weight of Cyanine Blue G-500 pure-A having a pigment concentration of 25% by weight. And stirred with a high-speed disper for 1 hour to obtain a pigment-dispersed slurry.

  The pigment dispersion slurry was continuously dispersed 20 times at a pressure of 200 MPa by a high pressure homogenizer (Microfluidizer, manufactured by Mizuho Kogyo Co., Ltd.) to obtain a pigment dispersion.

    Further, MEK was removed from the pigment dispersion by distillation under reduced pressure, and centrifuged at 5000 rpm for 30 minutes with a centrifuge (05P-21, manufactured by Hitachi, Ltd.), and then ion-exchanged water was added so that the pigment concentration was 15% by weight. The pigment dispersion for inkjet ink was added and adjusted. Then, after pressure filtration using a 2.5 μm membrane filter (manufactured by Advantech), ion-exchanged water was added so as to obtain a pigment concentration of 4% by weight, whereby an inkjet ink according to Example 15 was obtained. It was.

  Instead of 480.0 parts by weight of Cyanine Blue G-500 pure-A pigment paste refined by a conventional method, a pigment paste having a pigment concentration of 25% by weight obtained by standardizing fine particles of Fast Yellow 7413-A (average pigment) 480.0 parts by weight of primary particle diameter 57 nm), and ion-exchanged water was added so that the pigment concentration was 6% by weight instead of adding ion-exchanged water so that the pigment concentration was 4% by weight. Were carried out in the same manner as in Example 15 to obtain an inkjet ink according to Example 16.

  Pigment paste of Pigment Violet GC227-A finely divided by conventional method instead of 480.0 parts by weight of pigment paste of Cyanine Blue G-500 pure-A refined by conventional method (average primary pigment) (Particle size 35 nm) 480.0 parts by weight was used, and instead of adding ion-exchanged water so that the pigment concentration was 4% by weight, ion-exchanged water was added so that the pigment concentration was 6% by weight. In the same manner as in Example 15, an inkjet ink according to Example 17 was obtained.

  The polymer composition solution for inkjet inks having a resin solid content of 50% used in Example 2 was used, and then 6.0 parts by weight of 30% aqueous sodium hydroxide solution with respect to 120.0 parts by weight of the polymer composition solution for inkjet inks. And 128 parts by weight of MEK to give a total MEK amount of 188 parts by weight, followed by stirring for 5 minutes with a high-speed disper and further finely pulverizing Cyanine Blue G-500 pure-A by a conventional method, a pigment paste having a pigment concentration of 25% by weight ( 480.0 parts by weight of pigment (average primary particle diameter 45 nm) was added and stirred for 1 hour with a high-speed disper to obtain a pigment-dispersed slurry.

  The pigment dispersion slurry was continuously dispersed 20 times at a pressure of 200 MPa by a high pressure homogenizer (Microfluidizer, manufactured by Mizuho Kogyo Co., Ltd.) to obtain a pigment dispersion.

    Further, MEK was removed from the pigment dispersion by distillation under reduced pressure, and centrifuged at 5000 rpm for 30 minutes with a centrifuge (05P-21, manufactured by Hitachi, Ltd.), and then ion-exchanged water was added so that the pigment concentration was 15% by weight. The pigment dispersion for inkjet ink was added and adjusted. Then, after pressure filtration using a 2.5 μm membrane filter (manufactured by Advantech Co., Ltd.), an ink-jet ink according to Example 18 was obtained that was adjusted by adding ion-exchanged water so that the pigment concentration was 4% by weight. It was.

  Ink-jet ink according to Example 19 except that MEK 128 parts by weight is added to make MEK total amount 188 parts by weight, except that MEK 192 parts by weight is added to make MEK total amount 252 parts by weight. Got.

  Ink-jet ink according to Example 20 except that MEK 128 parts by weight was added to make MEK total amount 188 parts by weight, except that MEK 246 parts by weight was added to make MEK total amount 306 parts by weight. Got.

  Instead of 480.0 parts by weight of Cyanine Blue G-500 pure-A pigment paste refined by a conventional method, a pigment paste having a pigment concentration of 25% by weight obtained by standardizing fine particles of Fast Yellow 7413-A (average pigment) 480.0 parts by weight of primary particle diameter 57 nm), and ion-exchanged water was added so that the pigment concentration was 6% by weight instead of adding ion-exchanged water so that the pigment concentration was 4% by weight. Were carried out in the same manner as in Example 18 to obtain an inkjet ink according to Example 21.

  Pigment paste of Pigment Violet GC227-A finely divided by conventional method instead of 480.0 parts by weight of pigment paste of Cyanine Blue G-500 pure-A refined by conventional method (average primary pigment) (Particle size 35 nm) 480.0 parts by weight was used, and instead of adding ion-exchanged water so that the pigment concentration was 4% by weight, ion-exchanged water was added so that the pigment concentration was 6% by weight. In the same manner as in Example 18, an inkjet ink according to Example 22 was obtained.

  The polymer composition solution for inkjet inks having a resin solid content of 50% used in Example 2 was used, and then 6.0 parts by weight of 30% aqueous sodium hydroxide solution with respect to 120.0 parts by weight of the polymer composition solution for inkjet inks. And MEK 128 parts by weight to give a total MEK amount of 188 parts by weight, followed by stirring with a high-speed disper for 5 minutes, and further Cyanine Blue 2045 (PB-15: 1; average primary particle diameter of pigment 70 nm; Sanyo dye) 120.0 parts by weight) was added and stirred with a high speed disper for 1 hour to obtain a pigment dispersion slurry.

  The pigment dispersion slurry was continuously dispersed 20 times at a pressure of 200 MPa by a high pressure homogenizer (Microfluidizer, manufactured by Mizuho Kogyo Co., Ltd.) to obtain a pigment dispersion.

  Further, MEK was removed from the pigment dispersion by distillation under reduced pressure, and centrifuged at 5000 rpm for 30 minutes with a centrifuge (05P-21, manufactured by Hitachi, Ltd.), and then ion-exchanged water was added so that the pigment concentration was 15% by weight. The pigment dispersion for inkjet ink was added and adjusted. Then, after pressure filtration using a 2.5 μm membrane filter (manufactured by Advantech), ion-exchanged water was added so as to obtain a pigment concentration of 4% by weight, whereby an inkjet ink according to Example 23 was obtained. It was.

  Instead of a pigment paste obtained by atomizing Cyanine Blue G-500 pure-A by a conventional method, Fast Yellow 7413 (PY-74; average primary particle diameter of pigment 90 nm; manufactured by Sanyo Dye Co., Ltd.) is used. The same procedure as in Example 23 was performed except that ion-exchanged water was added so that the pigment concentration was 6% by weight instead of adding ion-exchanged water so that the pigment concentration was 4% by weight. Such an ink-jet ink was obtained.

  Instead of a pigment paste obtained by atomizing Cyanine Blue G-500 pure-A by a conventional method, PV Fast Red E5B (PV-19; average primary particle diameter of pigment: 85 nm; manufactured by Clariant Corporation) is used. The same procedure as in Example 23 was performed except that ion-exchanged water was added so that the pigment concentration was 6% by weight instead of adding ion-exchanged water so that the pigment concentration was 4% by weight. Such an ink-jet ink was obtained.

<Evaluation Method 1> Gloss Value The inkjet inks according to Examples 1 to 25 and Comparative Examples 1 to 6 are solid on PM photographic paper (Seiko Epson Corporation) with an inkjet printer (EM-930C, Seiko Epson Corporation). Printing was performed to obtain a test specimen. The 20 degree gloss of this test specimen was measured with a gloss meter (HG-268, manufactured by Suga Test Instruments Co., Ltd.). The results are shown in Tables 1-3.

<Evaluation Method 2> Average Particle Diameter The average particle diameter of the particles in the inkjet inks according to Examples 1 to 25 and Comparative Examples 1 to 6 was measured with a laser particle size analyzer (LPA-3100, manufactured by Otsuka Electronics Co., Ltd.). did. The results are shown in Tables 1-3.

<Evaluation Method 3> Stability The initial viscosity of the pigment dispersion for inkjet ink used in Examples 1 to 25 and Comparative Examples 1 to 6 and the viscosity after standing at 70 ° C. for 1 week were measured using an E-type viscometer (RE -80L, manufactured by TOKIMEC). The result was calculated by the following formula (1) and shown in Tables 1 to 3.
Stability = viscosity after standing for 1 week at 70 ° C. (mPa · s) / initial viscosity (mPa · s) (1)
<Evaluation Method 4> Gloss change The inkjet inks according to Examples 1 to 25 and Comparative Examples 1 to 6 were solid on PM photographic paper (Seiko Epson Corporation) using an inkjet printer (EM-930C, Seiko Epson Corporation). Printing was performed to obtain a test specimen. The state of change in gloss when the solid print of this specimen was rubbed with a finger was visually observed. The results are shown in Tables 1-3.
A: No change at all O: Almost no change Δ: A slight change is observed X: A remarkable change is observed <Evaluation Method 5> The inkjet inks according to Fixing Examples 1 to 25 and Comparative Examples 1 to 6 are used as an inkjet printer. (EM-930C, manufactured by Seiko Epson Corporation) was printed on PM photographic paper (manufactured by Seiko Epson Corporation) to obtain a test specimen. The state in which the color was transferred to an unprinted portion when the test piece was rubbed with a finger was visually observed. The results are shown in Tables 1-3.
◎: No change at all ○: Almost no change Δ: Some change is observed ×: Significant change is recognized Note that Tables 1 to 3 show the compositions, polymerization initiators and pigments used in producing the ink-jet ink. In addition, physical properties of the polymer composition for inkjet ink are also shown. Moreover, the manufacturing method of the pigment dispersion for inkjet ink of this invention was shown with the following symbol.
A: Without adding an alcohol solvent or a ketone solvent to the ink jet ink polymer composition, an aqueous medium, an alkali or the like is added and emulsified by high-speed stirring, and a pigment or the like is added and dispersed strongly. Subsequently, the organic solvent etc. are removed from the obtained pigment dispersion.
B: Solvent was removed from the ink-jet ink polymer composition after polymerization by distillation under reduced pressure, the solid matter of the obtained ink-jet ink polymer composition was pulverized, and ion-exchanged water, an alkali solution, etc. were added and dissolved by heating. And using the obtained polymer composition solution for inkjet ink.
C: A method of using a polymer composition solution for ink-jet ink in which an alkali solution is added to the polymer composition for ink-jet ink that has been polymerized and heated, and then the solvent is removed and replaced with ion-exchanged water or the like.
D: The ink-jet ink polymer composition solution containing the ink-jet ink polymer composition and the alcohol solvent or the ketone solvent contains 10 parts by weight or more of the alcohol solvent or the ketone solvent to 100 parts by weight of the pigment. In addition to adding an aqueous medium, alkali, etc. and emulsifying by high-speed stirring, adding a pigment, etc., dispersing strongly, then removing the organic solvent, etc. from the resulting pigment dispersion How to remove.

  As is clear from the results in Tables 1 to 3, the gloss values of the test bodies using the inkjet inks according to Examples 1 to 25 are higher than the gloss values of the test bodies using the inkjet inks according to Comparative Examples 1 to 6. It has become. Moreover, the average particle diameter of the particle | grains in the inkjet ink which concerns on Examples 1-25 is smaller than the average particle diameter of the particle | grains in the inkjet ink which concerns on Comparative Examples 1-6. Therefore, the ink-jet ink according to Examples 1 to 25 is suitable for use in a printed photograph using a digital camera. In particular, the average particle diameter of the particles in the inkjet ink according to Examples 10 to 12 is small, and the pigment dispersion for inkjet ink used in Examples 10 to 12 has a viscosity after standing at 70 ° C. for 1 week. It is almost unchanged and excellent.

In addition, the ink-jet inks according to Examples 15 to 25 improved the fixability, and in particular, the ink-jet ink according to Examples 15 to 22 used a finely divided pigment, so that the gloss change was further improved. .

Claims (6)

An inkjet ink pigment dispersion containing an inkjet ink polymer, a pigment, and an aqueous medium,
The ink-jet ink polymer comprises cyclohexyl acrylate (A1) and / or benzyl acrylate (A2) comprising 8% by weight to 98% by weight, methacrylic acid (B) comprising 1% by weight to 31% by weight, and 1 Obtained by polymerization of a monomer containing acrylic acid (C) consisting of 25% by weight or more and 25% by weight or less , and the ink jet ink polymer has an acid value of 10 mgKOH / g or more and 200 mgKOH / g or less,
The average particle diameter of the inkjet ink obtained by this pigment dispersion is 60 nm or more and 97 nm or less, The pigment dispersion for inkjet inks characterized by the above-mentioned . The pigment dispersion for inkjet ink according to claim 1 , wherein the monomer further contains (meth) acrylate (D1) having a long-chain alkyl group in an amount of 20% by weight or less. The monomers further having an amino group (meth) acrylate (D2) an inkjet ink for pigment dispersion according to claim 1 or 2 containing 20% by weight or less. The monomer further has a hydroxyl group (meth) inkjet ink pigment dispersion according to any of claims 1 to 3 acrylate (D3) containing 20 wt% or less. The pigment dispersion for inkjet ink according to any one of claims 1 to 4, wherein the polymer for inkjet ink has a weight average molecular weight of 5,000 to 150,000. It is a manufacturing method of the pigment dispersion for ink-jet inks in any one of Claims 1-5,
A method for producing a pigment dispersion for inkjet ink, comprising a dispersion step in which an alcohol solvent or a ketone solvent is added in an amount of 10 to 280 parts by weight and dispersed with respect to 100 parts by weight of the pigment.