JP2013199605A - Binder for inkjet printing ink, the inkjet printing ink containing the same, and printed matter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a binder for inkjet printing ink, and the inkjet printing ink that can form a printed image having extremely excellent ejection stability and extremely excellent durability such as scratch resistance and alkali resistance of ink.SOLUTION: A binder for inkjet printing ink is obtained by dispersing, in an aqueous medium (D), polyurethane (C) having a structure derived from a vinyl polymer (a1) in a side-chain, obtained by reaction between polyol (A) and polyisocyanate (B), the polyol (A) containing the vinyl polymer (a1) having a comparatively long-chained alkyl group and two hydroxyl groups at one end, and one or more kinds of polyol (a2) selected from a group consisting of polyether polyol, polyester polyol, polyester ether polyol and polycarbonate polyol. Printed matter is also provided.

Description

  The present invention relates to an ink binder that can be used in ink jet printing and an ink for ink jet printing including the same.

  In recent years, in the industry related to ink-jet printing, which has been growing rapidly, the performance of ink-jet printers and the improvement of ink have progressed dramatically, making it possible to easily obtain high-gloss and high-definition images comparable to silver halide photographs even in ordinary households. It is becoming.

  In particular, improvements have been made rapidly with the aim of improving image quality and reducing environmental impact, such as the transition from conventional dye inks to pigment inks and from solvent-based to water-based inks. Is actively developing inks based on water-based pigment inks.

  In addition, with the improvement in performance of ink jet printers and the like, higher levels of performance are required for the ink year after year. For example, the ink has good ejection stability and storage stability. Scratch resistance at a level that can prevent discoloration and deterioration of the printed image due to missing pigment due to friction that can occur when external force is applied to the surface of the printed image without damaging, and glass cleaner In recent years, there has been a strong demand for durability such as chemical resistance at a level that does not cause bleeding or discoloration of a printed image when various cleaning agents adhere to the surface of the printed image.

  The ink having excellent scratch resistance is obtained by, for example, reacting an organic diisocyanate with a diol having a polyoxyethylene structure in an inkjet recording ink containing a pigment, an aqueous resin, and an aqueous medium. An ink for inkjet recording, which is a polyurethane resin, has a carboxyl group and has a specific acid value, a number average molecular weight, and a specific amount of the polyoxyethylene structure is known ( For example, see Patent Document 1.)

  An image obtained by printing using the ink jet recording ink has a certain degree of scratch resistance, for example, it can prevent the pigment from dropping off due to rubbing between papers.

  However, as the field of use of ink-jet printed materials has become widespread, printed images formed using the ink-jet recording ink are, for example, locally, while a higher level of scratch resistance is required. When a strong external force is applied, the printed image may still be discolored, deteriorated, or damaged due to the dropping of the pigment. In addition, an image obtained by printing using the ink jet recording ink has a problem in that, for example, when an alkaline cleaning agent or the like adheres to the surface, the printing surface is floated or smeared.

  By the way, the diameter of the ink discharge nozzle provided in the ink jet printer is becoming thinner so that a very small amount of ink can be discharged while a high-gloss and high-definition printed image similar to a silver salt photograph is required. is there. Even when the ink discharge nozzle is thin, the ink discharge nozzle can be stably discharged over a long period of time without causing clogging of the ink discharge nozzle over time or abnormal ink discharge direction (discharge stability) Property) is required for both the ejection nozzle and the ink.

  In particular, the ejection stability of ink for ink jet printing may cause a significant decrease even when the ink composition is slightly adjusted to improve the durability such as the scratch resistance. For this reason, there is a need for ink-jet printing inks that can form printed images that have both excellent ink ejection stability and very good scratch resistance and excellent alkali resistance. In fact, the ink-jet printing ink and the ink-jet printing ink binder that can be used in the production of the ink-jet printing ink have not yet been found.

JP 2000-1639 A

  The problem to be solved by the present invention is ink jet printing which achieves both excellent discharge stability of ink and formation of a printed image having excellent durability such as scratch resistance and alkali resistance. An ink binder and an ink for inkjet printing containing the binder are provided.

  While the inventors have studied to solve the above problems, the polyurethane component and the vinyl polymer component are not simply mixed, but are derived from the vinyl polymer (a1) in the side chain in which they form a bond. It was found that the problems of the present invention can be solved by using a binder for inkjet printing inks containing a polyurethane having the following structure and an aqueous medium.

  That is, the present invention includes a vinyl polymer (a1) having a functional group (X) represented by the following general formula (I) and having two hydroxyl groups at one end, a polyether polyol, a polyester polyol, A vinyl polymer in the side chain obtained by reacting a polyol (A) containing at least one polyol (a2) selected from the group consisting of a polyester ether polyol and a polycarbonate polyol, and a polyisocyanate (B). The polyurethane (C) having a structure derived from (a1) is dispersed in an aqueous medium (D), and relates to a binder for inkjet printing ink and a printed matter.

[R in General Formula (I) represents an aliphatic alkyl group, an alicyclic alkyl group or an aromatic structure having 4 or more carbon atoms. ]

  Ink jet printing ink containing the ink jet printing ink binder of the present invention is excellent in ink ejection stability and storage stability, and does not cause pigment dropout even when a strong external force is applied. High-definition printed images can be maintained and durability such as scratch resistance comparable to silver salt photographs and excellent alkali resistance can be imparted. For example, photo printing by inkjet printing or high-speed printing by inkjet printing Can be used in various scenes such as outdoor advertising.

  The present invention includes a vinyl polymer (a1) having a functional group (X) represented by the following general formula (I) and having two hydroxyl groups at one end, a polyether polyol, a polyester polyol, and a polyester ether A polyol (A1) containing at least one polyol (a2) selected from the group consisting of a polyol and a polycarbonate polyol, and a vinyl polymer (a1) in the side chain obtained by reacting the polyisocyanate (B). The binder for inkjet printing inks, wherein the polyurethane (C) having a structure derived from (2) is dispersed in the aqueous medium (D).

[R in General Formula (I) represents an aliphatic alkyl group, an alicyclic alkyl group or an aromatic structure having 4 or more carbon atoms. ]
Here, the binder for inkjet printing ink is a resin used for the purpose of imparting high functionality to the inkjet printing ink.

  In the present invention, by using the above-mentioned specific binder for inkjet printing ink, it is excellent in ink ejection stability and storage stability, and has high-definition, silver-scratch-like scratch resistance, excellent alkali resistance, etc. It is possible to form a printed image having the above durability.

First, the polyurethane (C) used in the present invention will be described.
The polyurethane (C) used in the present invention is obtained by grafting a vinyl polymer structure onto a side chain of a polyurethane structure as a main chain. Specifically, as the polyurethane (C), a vinyl polymer (a1) having a functional group (X) represented by the following general formula (I) and having two hydroxyl groups at one end; Polyol (A) containing at least one polyol (a2) selected from the group consisting of polyether polyol, polyester polyol, polyester ether polyol and polycarbonate polyol, polyisocyanate (B), and chain extension as necessary What is obtained by reacting the agent is used.

[R in General Formula (I) represents an aliphatic alkyl group, an alicyclic alkyl group or an aromatic structure having 4 or more carbon atoms. ]

  Here, in the ink for inkjet printing obtained using the polyurethane which does not have a vinyl polymer structure derived from the vinyl polymer (a1) in the side chain instead of the polyurethane (C), the alkali resistance and water resistance In some cases, a printed matter having excellent durability such as the above cannot be formed.

  Ink-jet printing inks obtained using polyurethane having a vinyl polymer structure in the main chain instead of the polyurethane (C) may cause a significant decrease in ink ejection stability.

  Accordingly, in order to achieve both durability such as alkali resistance and excellent ink ejection stability, it is important to use polyurethane (C) having a structure derived from the vinyl polymer (a1) in the side chain. It is. The polyurethane (C) preferably contains 1% by mass to 70% by mass of a structure derived from the vinyl polymer (a1) based on the total amount of the polyurethane (C). It is more preferable to use those containing 5% by mass to 50% by mass in order to achieve both durability such as alkali resistance and water resistance and excellent ink ejection stability. More preferred.

  In the present invention, it is not only necessary to use polyurethane having a structure derived from the vinyl polymer in the side chain, but in the structure derived from the vinyl polymer (a1) constituting the side chain, the general formula It is particularly preferable to use the one having the functional group (X) represented by (I) in order to improve the alkali resistance of the printed matter.

  The structure represented by the general formula (I) is necessary for making the vinyl polymer (a1) a relatively hydrophobic structure. R in the general formula (I) is an aliphatic alkyl group, alicyclic alkyl group or aromatic structure having 4 or more carbon atoms, preferably 4 to 10 carbon atoms, such as an n-butyl group, i -Fatty alkyl groups such as butyl group, t-butyl group, 2-ethylhexyl group, hexyl group, octyl group, nonyl group, dodecyl group, stearyl group, isobornyl group, cyclohexyl group, dicyclopentanyl group, etc. Examples thereof include a cyclic alkyl group and a benzene ring. Among these, it is preferable to use an n-butyl group, an i-butyl group, a t-butyl group, a 2-ethylhexyl group, or a cyclohexyl group for further improving the ejection stability of the ink.

  The functional group (X) represented by the general formula (I) is preferably contained in an amount of 1% by mass to 60% by mass with respect to the entire polyurethane (C).

  Moreover, as said polyurethane (C), it is preferable to use what has a weight average molecular weight of the range of 10,000-150,000 from a viewpoint of providing the outstanding discharge stability of an ink, and 10,000-50. It is more preferable to use one having 1,000.

  Moreover, it is preferable that the said polyurethane (C) can exist in the state disperse | distributed in the aqueous medium (D). Examples of the method for dispersing the polyurethane (C) in the aqueous medium (D) include a method using a surfactant and a method using a polyurethane (C) having a hydrophilic group.

  The hydrophilic group can be introduced into the polyurethane (C) by using, for example, a polyol having a hydrophilic group. For example, an anionic group, a cationic group, or a nonionic group can be used. Among them, it is more preferable to use one or both of an anionic group and a cationic group, and it is particularly preferable to use an anionic group.

  As the anionic group, for example, a carboxyl group, a carboxylate group, a sulfonic acid group, a sulfonate group, and the like can be used. Among them, a part or all of the carboxyl group and the sulfonic acid group are formed by a basic compound or the like. It is preferable to use a neutralized carboxylate group or sulfonate group in order to provide excellent water dispersion stability. Moreover, as said cationic group, a tertiary amino group etc. can be used, for example. In addition, examples of the nonionic group include a polyoxyethylene structure.

  The hydrophilic group is preferably present in a range of 15 mmol / kg to 2,000 mmol / kg with respect to the entire polyurethane (C), and preferably in a range of 15 mmol / kg to 1,500 mmol / kg. It is more preferable for obtaining a binder for ink jet printing ink having excellent storage stability and ejection stability.

  Further, the present invention is for ink jet printing which can form a printed image having excellent scratch resistance and durability by simply using polyurethane having a vinyl polymer structure derived from the vinyl polymer (a1) in the side chain. Ink is not obtained, and one type selected from the group consisting of polyether polyol, polyester polyol, polyester ether polyol and polycarbonate polyol in the main chain of the polyurethane (C) together with the side chain consisting of the vinyl polymer structure It is important to have a structure derived from the above polyol (a2). By combining such specific structures, it is possible to obtain an ink jet ink binder that can solve the above-mentioned problems for the first time.

  Specific examples of the structure derived from the polyol (a2) include a polyether structure, a polyester structure, a polyetherester structure, and a polycarbonate structure.

  Here, in some cases, a printed matter having excellent scratch resistance may not be formed with a binder for ink jet printing ink using a polyurethane having no structure derived from the polyol (a2) instead of the polyurethane (C).

  The structure derived from the polyol (a2) is preferably included in the range of 5% by mass to 80% by mass with respect to the total amount of the polyurethane (C).

  The polyol (A) used in the production of the polyurethane (C) is a vinyl polymer having two hydroxyl groups at one end for the purpose of introducing a vinyl polymer structure into the side chain of the polyurethane structure as the main chain. One or more selected from the group consisting of polyether polyol, polyester polyol, polyester ether polyol and polycarbonate polyol for the purpose of using the coalescence (a1) and imparting excellent scratch resistance to the printed matter to be formed. It is important to use the polyol (a2).

  As the vinyl polymer (a1) having two hydroxyl groups at one end used for the production of the polyurethane (C), for example, in the presence of a chain transfer agent having two hydroxyl groups, The thing obtained by superposing | polymerizing the vinyl monomer which has the functional group (X) shown, and another vinyl monomer as needed can be used. Specifically, in the presence of a chain transfer agent (E) having two hydroxyl groups and a mercapto group, an aliphatic alkyl group or alicyclic alkyl having 4 or more carbon atoms, preferably 4 to 10 carbon atoms. Radical polymerization of a vinyl monomer (F) containing a (meth) acrylic acid alkyl ester having a group or an aromatic structure and polymerizing the vinyl monomer (F) starting from the mercapto group. . In the present invention, “(meth) acrylic acid” indicates one or both of acrylic acid and methacrylic acid.

  In addition, as the vinyl polymer (a1) having two hydroxyl groups at one end, for example, radical polymerization of a vinyl monomer in the presence of a chain transfer agent having a carboxyl group and a mercapto group, As a starting point, a polymer obtained by reacting the vinyl monomer with a compound having a hydroxyl group and a glycidyl group can be used.

  Since the obtained vinyl polymer (a1) has two hydroxyl groups derived from the chain transfer agent at one end, the two hydroxyl groups react with an isocyanate group of a polyisocyanate (B) described later. A urethane bond can be formed.

  As the vinyl polymer (a1) having two hydroxyl groups at one end, the viscosity control when reacting with the polyisocyanate (B) is facilitated, and the production efficiency of the binder for inkjet printing ink of the present invention is improved. From the viewpoint of improving the ink ejection stability, it is preferable to use those having a number average molecular weight of 500 to 10,000, and those having a number average molecular weight of 1,000 to 5,000 are used. More preferred.

  In addition, as the vinyl polymer (a1), a hydrophilic group-containing vinyl is provided from the viewpoint of imparting a hydrophilic group to the obtained polyurethane (C) and imparting excellent storage stability to the binder for inkjet printing ink of the present invention. Polymers can also be used.

  As the hydrophilic group, an anionic group, a cationic group, and a nonionic group can be used. As the hydrophilic group that can be present in the vinyl polymer (a1), an anionic group and a cationic group can be used. Either one or a combination of both is preferable, and a cationic group is more preferable.

  As the anionic group, for example, a carboxyl group, a carboxylate group, a sulfonic acid group, a sulfonate group, and the like can be used. Among them, a part or all of the carboxyl group and the sulfonic acid group are formed by a basic compound or the like. It is preferable to use a neutralized carboxylate group or sulfonate group in order to impart good water dispersion stability. As the cationic group, for example, a tertiary amino group can be used, and as the nonionic group, for example, a polyethylene oxide chain can be used.

  In addition, the vinyl polymer (a1) has a vinyl polymer structure derived from the vinyl polymer (a1) in the side chain of the polyurethane (C) other than the two hydroxyl groups at one end. It is preferable that it does not have another hydroxyl group. Specifically, it is preferable not to use a hydroxyl group-containing vinyl monomer as the vinyl monomer (F) that can be used in the production of the vinyl polymer (a1).

  Examples of the chain transfer agent that can be used for the production of the vinyl polymer (a1) having two hydroxyl groups at one end include a chain transfer agent (E) having two hydroxyl groups and a mercapto group, and a carboxyl group. A chain transfer agent having a mercapto group or the like can be used. Among these, it is preferable to use a chain transfer agent (E) having two hydroxyl groups and a mercapto group because the production is simple.

  Examples of the chain transfer agent (E) having two hydroxyl groups and a mercapto group include 3-mercapto-1,2-propanediol (thioglycerin), 1-mercapto-1,1-methanediol, and 1-mercapto. -1,1-ethanediol, 2-mercapto-1,3-propanediol, 2-mercapto-2-methyl-1,3-propanediol, 2-mercapto-2-ethyl-1,3-propanediol, 1 -Mercapto-2,3-propanediol, 2-mercaptoethyl-2-methyl-1,3-propanediol, 2-mercaptoethyl-2-ethyl-1,3-propanediol and the like can be used. Among them, it is preferable to use 3-mercapto-1,2-propanediol because it has less odor, is excellent in terms of workability and safety, and is versatile.

  Moreover, as a vinyl monomer (F) which can be used for manufacture of the said vinyl polymer (a1), for example, the vinyl monomer which has a functional group (X) shown by the said general formula (I) should be used. Examples thereof include aliphatic alkyl groups having 4 or more carbon atoms, alicyclic alkyl groups, and (meth) acrylic acid alkyl esters having an aromatic structure.

  Examples of the (meth) acrylic acid alkyl ester having an aliphatic alkyl group or an alicyclic alkyl group having 4 or more carbon atoms include n-butyl (meth) acrylate, i-butyl (meth) acrylate, t-butyl ( (Meth) acrylate, 2-ethylhexyl (meth) acrylate, hexyl (meth) acrylate, cyclohexyl (meth) acrylate, octyl (meth) acrylate, nonyl (meth) acrylate, dodecyl (meth) acrylate, stearyl (meth) acrylate, isobornyl ( (Meth) acrylate, dicyclopentanyl (meth) acrylate, phenyl (meth) acrylate, (meth) acrylic acid alkyl esters such as benzyl (meth) acrylate, and the like can be used. Among them, n-butyl (meth) acrylate, i-butyl (meth) acrylate, t-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, cyclohexyl (meth) acrylate, and benzyl (meth) acrylate should be used. However, it is preferable for obtaining an ink for ink jet printing excellent in alkali resistance. In addition, "(meth) acrylate" as used in the field of this invention shows one or both of an acrylate or a methacrylate.

  The vinyl monomer having the functional group (X) represented by the general formula (I) may be used in the range of 5% by mass to 100% by mass with respect to the total amount of the vinyl monomer (F). It is preferable for obtaining an ink for inkjet printing having excellent alkali resistance, and more preferably used in the range of 10% by mass to 100% by mass.

  As the vinyl monomer (F), a vinyl monomer other than the vinyl monomer having the functional group (X) represented by the general formula (I) is used in combination as long as the effects of the present invention are not impaired. For example, (meth) acrylic acid, β-carboxyethyl (meth) acrylate, 2- (meth) acryloylpropionic acid, crotonic acid, itaconic acid, maleic acid, fumaric acid, itaconic acid half ester, maleic acid half Acid group or acid anhydride group-containing vinyl monomer such as ester, maleic anhydride, itaconic anhydride ;; (meth) acrylamide, N-monoalkyl (meth) acrylamide, N, N-dialkyl (meth) acrylamide, N- Methylol (meth) acrylamide, N-isopropoxymethyl (meth) acrylamide, N-butoxymethyl (meth) acrylamide N-isobutoxymethyl (meth) acrylamide; 2-aziridinylethyl (meth) acrylate; N, N-dimethylaminoethyl (meth) acrylate, N, N-dimethylaminopropyl (meth) acrylate, N, N-diethylamino Ethyl (meth) acrylate, N, N-dimethylaminopropyl (meth) acrylate, N, N-diethylaminopropyl (meth) acrylate, N- [2- (meth) acryloyloxyethyl] piperidine, N- [2- (meta ) Acryloyloxyethyl] pyrrolidine, N- [2- (meth) acryloyloxyethyl] morpholine, 4- [N, N-dimethylamino] styrene, 4- [N, N-diethylamino] styrene, 2-vinylpyridine; N -Methylaminoethyl (meth) acrylate, Nt Butylaminoethyl (meth) acrylate; nitrogen atoms such as aminomethyl acrylate, aminoethyl acrylate, aminopropyl (meth) acrylate, amino-n-butyl (meth) acrylate, butylvinylbenzylamine, vinylphenylamine, p-aminostyrene -Containing vinyl monomers; nitriles of unsaturated carboxylic acids such as (meth) acrylonitrile; 2,2,2-trifluoroethyl (meth) acrylate, 2,2,3,3-pentafluoropropyl (meth) acrylate , Fluorine-containing vinyl monomers such as perfluorocyclohexyl (meth) acrylate; vinyl esters such as vinyl acetate, vinyl propionate and vinyl versatate; methyl vinyl ether, ethyl vinyl ether, propyl vinyl ether, butyl vinyl Vinyl ethers such as ether; vinyl compounds having an aromatic ring such as styrene, α-methylstyrene, divinylstyrene; isoprene, chloroprene, butadiene, ethylene, tetrafluoroethylene, vinylidene fluoride, N-vinylpyrrolidone; polyoxyethylene monomethyl Polyoxyethylene group-containing vinyl polymers such as ether (meth) acrylate and polyoxyethylene monoethyl ether (meth) acrylate can be used.

  The polymerization reaction between the chain transfer agent (E) having two hydroxyl groups and a mercapto group and the vinyl monomer (F) is carried out under a solvent such as toluene or methyl ethyl ketone adjusted to a temperature of about 50 ° C. to 100 ° C., for example. The chain transfer agent (E) and the vinyl monomer (F) can be fed all at once or sequentially, and can proceed by radical polymerization. Thus, radical polymerization of the vinyl monomer (F) proceeds from the mercapto group of the chain transfer agent (E) as a starting point, and a vinyl polymer (a1) having two hydroxyl groups at one end is produced. Can do. When producing a vinyl polymer (a1) having two hydroxyl groups at one end by the above method, a conventionally known polymerization initiator may be used as necessary.

  The vinyl polymer (a1) having two hydroxyl groups at one end obtained by the above method is used in the range of 1% by mass to 70% by mass with respect to the total mass of raw materials used for the production of the polyurethane (C). It is preferable to use in the range of 1% by mass to 65% by mass, and it is preferable to use in the range of 5% by mass to 50% by mass to form a printed matter excellent in alkali resistance and water resistance. And more preferable. In addition, the raw material used for manufacture of the said polyurethane (C) is the polyol (A) containing the said vinyl polymer (a1), the said polyol (a2), and other polyol (a3) which can be used if needed, The total mass of the polyisocyanate (B) indicates the total mass of the polyol (A), the polyisocyanate (B) and the chain extender when a chain extender is used. The same applies hereinafter.

  In addition, the polyol (a2) used in the production of the polyurethane (C) is an essential component for obtaining a printed material having excellent scratch resistance. Here, instead of the polyurethane (C), the side chain obtained by reacting the vinyl polymer (a1) and the polyisocyanate (B) without using the polyol (a2) has a vinyl polymer (a1 ) Inkjet printing ink binders using polyurethane having a derived structure may not be able to form printed matter with excellent scratch resistance.

  As said polyol (a2), 1 or more types chosen from the group which consists of polyether polyol, polyester polyol, polyester ether polyol, and polycarbonate polyol are used. Among these, it is preferable to use a polyether polyol from the viewpoint of improving the storage stability of the ink and the water resistance of the obtained printed matter.

  As the polyether polyol, for example, one obtained by addition polymerization of alkylene oxide using one or more compounds having two or more active hydrogen atoms as an initiator can be used.

  Examples of the initiator include ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, trimethylene glycol, 1,3-butanediol, 1,4-butanediol, 1,6-hexanediol, glycerin, trimethylolethane, Trimethylolpropane and the like can be used.

  Examples of the alkylene oxide include ethylene oxide, propylene oxide, butylene oxide, styrene oxide, epichlorohydrin, and tetrahydrofuran.

  Specifically, polyoxytetramethylene glycol, polyoxypropylene glycol, or polyoxyethylene glycol is preferably used as the polyether polyol from the viewpoint of improving ink ejection stability. Moreover, as said polyether polyol, it is more preferable to use a thing with a number average molecular weight of 1,000-3,000, in order to suppress the tack feeling of the printing surface and to obtain the printed matter excellent in water resistance.

  Examples of the polyester polyol include a ring-opening polymerization reaction of a cyclic ester compound such as an aliphatic polyester polyol, an aromatic polyester polyol, or ε-caprolactone obtained by esterifying a low molecular weight polyol and a polycarboxylic acid. Polyesters obtained by the above, copolymerized polyesters thereof, and the like can be used.

  Examples of the low molecular weight polyol include ethylene glycol and propylene glycol.

  Examples of the polycarboxylic acid that can be used include succinic acid, adipic acid, sebacic acid, dodecanedicarboxylic acid, terephthalic acid, isophthalic acid, phthalic acid, and anhydrides or ester-forming derivatives thereof.

  Moreover, as said polyester ether polyol, what reacted the polyether polyol which the said alkylene oxide added to the said initiator and polycarboxylic acid can be used, for example. As the initiator and the alkylene oxide, the same ones exemplified as those usable when the polyether polyol is produced can be used. Moreover, as said polycarboxylic acid, the thing similar to what was illustrated as what can be used when manufacturing the said polyester polyol can be used.

  Moreover, as said polycarbonate polyol, what is obtained by making carbonate ester and a polyol react, for example, what is obtained by making phosgene, bisphenol A, etc. react can be used.

  As the carbonate ester, methyl carbonate, dimethyl carbonate, ethyl carbonate, diethyl carbonate, cyclocarbonate, diphenyl carbonate and the like can be used.

  Examples of the polyol capable of reacting with the carbonate ester include ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, dipropylene glycol, 1,4-butanediol, 1,3- Butanediol, 1,2-butanediol, 2,3-butanediol, 1,5-pentanediol, 1,5-hexanediol, 2,5-hexanediol, 1,6-hexanediol, 1,7-heptane Diol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, 3-methyl-1,5-pentanediol, 2- Ethyl-1,3-hexanediol, 2-methyl-1,3-propa Diol, 2-methyl-1,8-octanediol, 2-butyl-2-ethylpropanediol, 2-methyl-1,8-octanediol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, hydroquinone Relatively low molecular weight dihydroxy compounds such as resorcin, bisphenol-A, bisphenol-F, 4,4′-biphenol, polyether polyols such as polyethylene glycol, polypropylene glycol, polytetramethylene glycol, polyhexamethylene adipate, Polyester polyols such as polyhexamethylene succinate and polycaprolactone can be used.

  The polyol (a2) preferably has a weight average molecular weight of 500 to 10,000, and has a number average molecular weight in the range of 1,000 to 3,000, from the viewpoint of obtaining a printed material having excellent durability. More preferably, is used.

  It is preferable to use the said polyol (a2) in 5 mass%-80 mass% with respect to the total mass of the raw material used for manufacture of the said polyurethane (C). Furthermore, it is preferable to use it in the range of 15% by mass to 80% by mass in order to form a printed matter having excellent scratch resistance.

  The polyol (a2) is preferably used in combination with the vinyl polymer (a1) in a specific range in order to form a printed matter excellent in scratch resistance, for example, [(a1) / (a2) ] = 1/20 to 20/1, preferably 1/10 to 10/1.

  Moreover, as a polyol (A) used for manufacture of the said polyurethane (C), other polyol (a3) can be used as needed besides the above-mentioned thing.

  As the other polyol (a3), for example, a polyol (a3-1) having a hydrophilic group can be used. In particular, when the vinyl polymer (a1) having no hydrophilic group is used, the resulting polyurethane (C) is imparted with water dispersibility and has excellent storage stability. From the viewpoint of obtaining the above, it is preferable to use the hydrophilic group-containing polyol (a3-1).

  As the polyol (a3-1) having a hydrophilic group, those having a hydrophilic group can be used, and examples thereof include a polyol having an anionic group, a polyol having a cationic group, and a nonionic group. A polyol can be used, and among them, it is preferable to use a polyol having an anionic group or a polyol having a cationic group.

  As the polyol having an anionic group, for example, a polyol having a carboxyl group or a polyol having a sulfonic acid group can be used.

  Examples of the polyol having a carboxyl group include 2,2′-dimethylolpropionic acid, 2,2′-dimethylolbutanoic acid, 2,2′-dimethylolbutyric acid, 2,2′-dimethylolvaleric acid, and the like. Among them, it is preferable to use 2,2′-dimethylolpropionic acid. Moreover, the polyester polyol which has a carboxyl group obtained by making the polyol which has the said carboxyl group react with various polycarboxylic acids can also be used.

  Examples of the polyol having a sulfonic acid group include dicarboxylic acids such as 5-sulfoisophthalic acid, sulfoterephthalic acid, 4-sulfophthalic acid, and 5 [4-sulfophenoxy] isophthalic acid, and salts thereof, and the low molecular weight polyol. The polyester polyol obtained by reacting with can be used.

  The polyol having a carboxyl group and the polyol having a sulfonic acid group are preferably used in the range where the acid value of the polyurethane (C) is 10 to 70, more preferably 10 to 60. It is especially preferable to use in the range which becomes 20-60. In addition, the acid value said by this invention is the theoretical value computed based on the usage-amount of acid group containing compounds, such as a carboxyl group containing polyol used for manufacture of the said polyurethane (C).

  The anionic groups are preferably partially or wholly neutralized with a basic compound or the like in order to exhibit good water dispersibility.

  Examples of basic compounds that can be used for neutralizing the anionic group include organic amines having a boiling point of 200 ° C. or higher, such as ammonia, triethylamine, morpholine, monoethanolamine, and diethylethanolamine, NaOH, KOH, and LiOH. A metal hydroxide containing etc. can be used. The basic compound is preferably used in the range of basic compound / anionic group = 0.5 to 3.0 (molar ratio) from the viewpoint of improving the water dispersion stability of the resulting coating agent. It is more preferable to use in the range which becomes 0.9-2.0 (molar ratio).

  Further, as the cationic group-containing polyol, for example, a tertiary amino group-containing polyol can be used. Specifically, N-methyl-diethanolamine, a compound having two epoxies in one molecule, and a secondary amine. A polyol obtained by reacting with can be used.

  It is preferable that a part or all of the cationic group is neutralized with an acidic compound such as formic acid, acetic acid, propionic acid, succinic acid, glutaric acid, tartaric acid and adipic acid.

  Further, the tertiary amino group as the cationic group is preferably partly or entirely quaternized. As the quaternizing agent, for example, dimethyl sulfate, diethyl sulfate, methyl chloride, ethyl chloride and the like can be used, and dimethyl sulfate is preferably used.

  Moreover, as the polyol having the nonionic group, polyalkylene glycol having a structural unit derived from ethylene oxide can be used.

  The polyol (a3-1) having a hydrophilic group is preferably used in the range of 1% by mass to 45% by mass with respect to the total mass of raw materials used for the production of the polyurethane (C).

  Examples of the polyisocyanate (B) used for producing the polyurethane (C) include 4,4′-diphenylmethane diisocyanate, 2,4′-diphenylmethane diisocyanate, carbodiimide-modified diphenylmethane diisocyanate, crude diphenylmethane diisocyanate, phenylene diisocyanate, Aromatic polyisocyanates such as diisocyanate and naphthalene diisocyanate, aliphatic polyisocyanates such as hexamethylene diisocyanate, lysine diisocyanate, cyclohexane diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, xylylene diisocyanate, tetramethylxylylene diisocyanate, and alicyclic structures Having polyiso It is possible to use the Aneto. Among them, it is preferable to use an aliphatic polyisocyanate from the viewpoint of preventing yellow discoloration. From the viewpoint of further improving the scratch resistance and alkali resistance in addition to the above-mentioned discoloration prevention, a polyisocyanate having an aliphatic cyclic structure is preferably used. Preference is given to using isocyanates.

  The polyurethane (C) is, for example, in the absence of a solvent or in the presence of an organic solvent, one or more selected from the group consisting of the vinyl polymer (a1), polyether polyol, polyester polyol, polyester ether polyol, and polycarbonate polyol. Reacting a polyol (A) containing the polyol (a3) with other polyol (a3) such as a polyol (a3-1) having a hydrophilic group, if necessary, and the polyisocyanate (B). Can produce polyurethane (C). Specifically, the reaction is preferably performed in the range of 20 ° C. to 120 ° C. for about 30 minutes to 24 hours.

  In the reaction of the polyol (A) and the polyisocyanate (B), for example, the equivalent ratio of the isocyanate group of the polyisocyanate (B) to the hydroxyl group of the polyol (A) is 0.8 to 2.5. Preferably, it is carried out in the range of 0.9 to 1.5.

  Examples of the organic solvent that can be used for producing the polyurethane (C) include ketones such as acetone and methyl ethyl ketone; ethers such as tetrahydrofuran and dioxane; acetate esters such as ethyl acetate and butyl acetate; acetonitrile and the like. Nitriles; amides such as dimethylformamide and N-methylpyrrolidone can be used alone or in combination of two or more.

  When the polyurethane (C) used in the present invention is produced, a chain extender is used as necessary for the purpose of making the molecular weight relatively high and further improving the scratch resistance and the like. be able to.

  Since the polyurethane obtained by using the chain extender has a urea bond in the molecule, it can be suitably used for forming a printed image having excellent scratch resistance. On the other hand, since the polyurethane tends to lower the alcohol resistance due to the influence of the urea bond, the polyurethane (C) is used when forming a printed image excellent in the alcohol resistance as well as the scratch resistance and alkali resistance. As a polyurethane obtained without using a chain extender, a polyurethane obtained by limiting the amount of use to a minimum, specifically, the proportion of urea bonds contained in the polyurethane is 10% by mass It is preferable to use the following.

  As the chain extender that can be used when producing the polyurethane (C), polyamine, other active hydrogen atom-containing compounds, and the like can be used.

  Examples of the polyamine include ethylenediamine, 1,2-propanediamine, 1,6-hexamethylenediamine, piperazine, 2,5-dimethylpiperazine, isophoronediamine, 4,4′-dicyclohexylmethanediamine, and 3,3′-. Diamines such as dimethyl-4,4′-dicyclohexylmethanediamine, 1,4-cyclohexanediamine; N-hydroxymethylaminoethylamine, N-hydroxyethylaminoethylamine, N-hydroxypropylaminopropylamine, N-ethylaminoethylamine, N-methylaminopropylamine; diethylenetriamine, dipropylenetriamine, triethylenetetramine; hydrazine, N, N′-dimethylhydrazine, 1,6-hexamethylenebishydrazine; Razide, adipic acid dihydrazide, glutaric acid dihydrazide, sebacic acid dihydrazide, isophthalic acid dihydrazide; β-semicarbazide propionic acid hydrazide, 3-semicarbazide-propyl-carbazate, semicarbazide-3-semicarbazide methyl-3,5 5-Trimethylcyclohexane can be used, and ethylenediamine is preferably used.

  Examples of the other active hydrogen-containing compound include ethylene glycol, diethylene recall, triethylene glycol, propylene glycol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, hexamethylene glycol, and sucrose. Glycols such as methylene glycol, glycerin and sorbitol; phenols such as bisphenol A, 4,4′-dihydroxydiphenyl, 4,4′-dihydroxydiphenyl ether, 4,4′-dihydroxydiphenylsulfone, hydrogenated bisphenol A, hydroquinone , And water can be used alone or in combination of two or more thereof within a range in which the storage stability of the coating agent of the present invention is not lowered.

  The chain extender is preferably used, for example, in a range where the equivalent ratio of the amino group and excess isocyanate group of the polyamine is 1.9 or less (equivalent ratio), 0.3 to 1.0 (equivalent It is more preferable to use it in the range of the ratio.

  In addition, the aqueous production of the polyurethane (C) produced by the above method can be performed, for example, by the following method.

  [Method 1] After neutralizing or quaternizing some or all of the hydrophilic groups of the polyurethane (C) obtained by reacting the polyol (A) with the polyisocyanate (B), water is added. A method of dispersing polyurethane (C) in water.

  [Method 2] After neutralizing or quaternizing some or all of the hydrophilic groups of the polyurethane (C) obtained by reacting the polyol (A) and the polyisocyanate (B), water is added, A method in which polyurethane (C) is dispersed in water by chain extension using the chain extender as necessary.

  [Method 3] Polyurethane obtained by reacting polyol (A) and polyisocyanate (B), and if necessary, the same chain extender as above are charged in a reaction vessel in a batch or divided, A method of producing polyurethane (C) by chain extension reaction, then neutralizing or quaternizing some or all of the hydrophilic groups in the obtained polyurethane (C), and then adding water to disperse in water .

  In the [Method 1] to [Method 3], an emulsifier may be used as necessary. In addition, when water is dissolved or dispersed, a machine such as a homogenizer may be used as necessary.

  Examples of the emulsifier include nonionic emulsifiers such as polyoxyethylene nonylphenyl ether, polyoxyethylene lauryl ether, polyoxyethylene styryl phenyl ether, polyoxyethylene sorbitol tetraoleate, and polyoxyethylene / polyoxypropylene copolymer. Fatty acid salts such as sodium oleate, alkyl sulfates, alkylbenzene sulfonates, alkyl sulfosuccinates, naphthalene sulfonates, polyoxyethylene alkyl sulfates, alkane sulfonate sodium salts, sodium alkyl diphenyl ether sulfonates, etc. Anionic emulsifiers; Cationic emulsifiers such as alkylamine salts, alkyltrimethylammonium salts, and alkyldimethylbenzylammonium salts. It is. Among these, from the viewpoint of maintaining the excellent storage stability of the coating agent of the present invention, it is basically preferable to use an anionic or nonionic emulsifier. Moreover, as long as the mixing stability of the coating agent of the present invention can be maintained, for example, a cationic emulsifier and an amphoteric emulsifier may be used in combination.

  Moreover, when manufacturing the binder of this invention, you may use a hydrophilic group containing compound as an adjuvant which assists the water dispersibility of a polyurethane (C).

  As the compound having a hydrophilic group, a compound having an anionic group, a compound having a cationic group, a compound having an amphoteric group, or a compound having a nonionic group can be used.

  Examples of the compound having a nonionic group include a group having at least one active hydrogen atom in a molecule and consisting of a repeating unit of ethylene oxide, and a repeating unit of ethylene oxide and another alkylene oxide. A compound having at least one functional group selected from the group consisting of can be used.

  For example, polyoxyethylene glycol or polyoxyethylene-polyoxypropylene having a number average molecular weight of 300 to 20,000 containing at least 30% by mass of repeating units of ethylene oxide and containing at least one active hydrogen atom in the polymer Nonionic group-containing compounds such as copolymer glycols, polyoxyethylene-polyoxybutylene copolymer glycols, polyoxyethylene-polyoxyalkylene copolymer glycols or monoalkyl ethers thereof, or polyester polys obtained by copolymerizing these It is possible to use compounds such as ether polyols.

  Moreover, the binder for inkjet printing ink of this invention may use a hardening | curing agent and a curing catalyst together as needed in the range which does not reduce storage stability or ink discharge property.

  Examples of the curing agent include a compound having a silanol group and / or a hydrolyzable silyl group, a polyepoxy compound, a polyoxazoline compound, a polyisocyanate, and the like. Examples of the curing catalyst include lithium hydroxide. Sodium hydroxide, potassium hydroxide and the like can be used.

  The aqueous medium (D) used in the ink jet printing ink binder of the present invention is a solvent in which the polyurethane (C) can be dispersed. Examples of the aqueous medium (D) include water, an organic solvent miscible with water, and a mixture thereof. Examples of the organic solvent miscible with water include alcohols such as methanol, ethanol, n- and isopropanol; ketones such as acetone and methyl ethyl ketone; polyalkylene glycols such as ethylene glycol, diethylene glycol and propylene glycol; Alkyl ethers; lactams such as N-methyl-2-pyrrolidone, and the like. In the present invention, only water may be used, a mixture of water and an organic solvent miscible with water may be used, or only an organic solvent miscible with water may be used. From the viewpoint of safety and load on the environment, water alone or a mixture of water and an organic solvent miscible with water is preferable, and only water is particularly preferable.

  The polyurethane composition containing the polyurethane (C) and the aqueous medium (D) obtained by the above method can drastically improve the scratch resistance and alkali resistance of the printed matter. It can be suitably used for a binder resin.

  The ink jet printing ink binder is polyurethane (C) with respect to the total amount of the ink jet printing ink binder from the viewpoint of achieving both the storage stability of the ink, excellent scratch resistance and durability such as alkali resistance. It is preferable that 10-50 mass% is contained, and it is more preferable that 15-35 mass% is contained. The inkjet printing ink binder is preferably contained in an amount of 50% by mass to 90% by mass, and 65% by mass to 85% by mass of the aqueous medium (D) with respect to the total amount of the binder for inkjet printing ink. It is more preferable.

Next, the ink for inkjet printing of the present invention will be described.
The ink for ink-jet printing of the present invention contains the above-mentioned binder for ink-jet printing ink, pigments and dyes, and other various additives as required.

As the pigment, known and commonly used inorganic pigments and organic pigments can be used.
As the inorganic pigment, for example, titanium oxide, antimony red, bengara, cadmium red, cadmium yellow, cobalt blue, bitumen, ultramarine, carbon black, graphite and the like can be used.

  Examples of the organic pigment include quinacridone pigments, quinacridone quinone pigments, dioxazine pigments, phthalocyanine pigments, anthrapyrimidine pigments, ansanthrone pigments, indanthrone pigments, flavanthrone pigments, perylene pigments, Organic pigments such as diketopyrrolopyrrole pigments, perinone pigments, quinophthalone pigments, anthraquinone pigments, thioindigo pigments, benzimidazolone pigments, and azo pigments can be used.

  Two or more kinds of these pigments can be used in combination. These pigments may be surface-treated and have a self-dispersing ability with respect to an aqueous medium.

  Examples of the dye include azo dyes such as monoazo and disazo, metal complex dyes, naphthol dyes, anthraquinone dyes, indigo dyes, carbonium dyes, quinoimine dyes, cyanine dyes, quinoline dyes, nitro dyes, nitroso dyes, benzoquinone dyes, Naphthoquinone dyes, naphthalimide dyes, perinone dyes, phthalocyanine dyes, triallylmethane, and the like can be used.

  Examples of the additive include a dispersant, a viscosity modifier, a wetting agent, an antifoaming agent, a surfactant, a preservative, a pH adjuster, a chelating agent, a plasticizer, an ultraviolet absorber, and an antioxidant. An acrylic resin or the like that has been used as a binder for conventional ink jet printing inks can be used.

  The dispersant can be used for imparting dispersion stability of the coloring material such as the pigment in the aqueous medium (D). As the dispersant, for example, an acrylic resin, a styrene-acrylic resin, or the like can be used, and any of a random type, a block type, and a graft type can be used. When the dispersant is used, an acid or a base may be used in combination to neutralize the polymer dispersant.

  As the dispersant, an acrylic resin having a weight average molecular weight of preferably 1,000 to 50,000, more preferably 1,000 to 20,000, and a styrene-acrylic resin can be used. Moreover, as said dispersing agent, Preferably what has an acid value of 100-500, More preferably, 100-200 can be used.

  As the acrylic resin or styrene-acrylic resin, a polymer of acrylic acid or methacrylic acid, a polymer of these with styrene, or the like can be used.

  As said styrene-acrylic resin, it is preferable to use what is obtained by using 50 mass%-95 mass% of styrene with respect to the whole quantity of the monomer used for the manufacture.

  The ink for inkjet printing can be prepared, for example, by the following manufacturing method.

  (1) A method of preparing an ink by collectively mixing the pigment or dye, the aqueous medium, the ink jet printing ink binder and, if necessary, the additive using various dispersing devices.

  (2) An ink precursor composed of an aqueous dispersion of a pigment or dye is prepared by mixing the pigment or dye, the aqueous medium and, if necessary, the additive using various dispersing devices; A method of preparing an ink by mixing an ink precursor composed of an aqueous dispersion of the pigment or dye, the binder for an inkjet printing ink, and, if necessary, an aqueous medium and an additive using various dispersing devices.

  The ink precursor containing the pigment used in the ink production method described in (2) above can be prepared, for example, by the following method.

  (I) The pigment is obtained by mixing the kneaded product obtained by pre-kneading the pigment and the additive such as the dispersant using a two-roll or a mixer with an aqueous medium using various dispersing devices. A method for preparing an ink precursor comprising an aqueous dispersion.

  (Ii) After mixing the pigment and the dispersant using various dispersing devices, the dispersant is deposited on the surface of the pigment by controlling the solubility of the dispersing agent, and further using the dispersing device A method of preparing an ink precursor composed of an aqueous dispersion containing a pigment by mixing.

  (Iii) The pigment and the additive are mixed using various dispersing devices, and then the mixture and the resin emulsion are mixed using the dispersing device to prepare an ink precursor composed of an aqueous dispersion containing the pigment. how to.

  Examples of the dispersing device that can be used for manufacturing the ink for inkjet printing include, for example, an ultrasonic homogenizer, a high-pressure homogenizer, a paint shaker, a ball mill, a roll mill, a sand mill, a sand grinder, a dyno mill, a disperse mat, an SC mill, and a nanomizer. Alternatively, two or more types can be used in combination.

  Ink jet printing ink obtained by the above method may contain coarse particles having a particle diameter of approximately 250 nm or more. The coarse particles may cause clogging of printer nozzles and the like, and may deteriorate ink discharge characteristics. Therefore, the coarse particles may be coarsened by a method such as centrifugation or filtration after the preparation of the aqueous dispersion of the pigment or after the preparation of the ink. It is preferred to remove the particles.

  The ink for ink jet printing obtained above preferably has a volume average particle diameter of 200 nm or less, particularly in the case of forming a higher gloss image such as photographic image quality, the range of 80 to 120 nm. It is more preferable that

  The inkjet printing ink is 0.2 to 10% by mass of the polyurethane (C), 50 to 95% by mass of an aqueous medium, and 0.5 to 15% of a pigment or dye based on the entire inkjet printing ink. It is preferable to contain the mass%.

  The ink for ink jet printing of the present invention obtained by the above method can be used exclusively for ink jet printing using an ink jet printer, for example, ink jet printing on a substrate such as paper, plastic film, metal film or sheet. be able to. The ink jet method is not particularly limited, but a known method such as a continuous jet type (charge control type, spray type, etc.) or an on-demand type (piezo type, thermal type, electrostatic suction type, etc.) should be applied. Can do.

  Since the printed matter printed using the ink for ink jet printing of the present invention has excellent scratch resistance, it is difficult to cause deterioration of a printed image due to lack of pigments and the like, and has excellent alkali resistance. Since it has a high color density image, it can be prevented by bleed or the like due to adhesion of alkaline detergent to the printed image surface, and can be obtained, for example, by photographic printing by inkjet printing or high-speed printing by inkjet printing. It can be used for various purposes such as printed materials.

  Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples.

[Preparation Example 1] Preparation of vinyl polymer (a1-1) having two hydroxyl groups at one end In a four-necked flask equipped with a thermometer, a stirrer, a reflux condenser and a nitrogen inlet tube, 700 parts by mass of methyl ethyl ketone Then, 291 parts by mass of t-butyl methacrylate, 8.7 parts by mass of 3-mercapto-1,2-propanediol, and 2,2′-azobis (2-methylpropionitrile) were added to the reaction vessel. A solvent solution of a vinyl polymer (a1-1) having two hydroxyl groups at one end with a number average molecular weight of 3,000 was obtained by supplying and reacting 15 parts by mass.

[Preparation Example 2] Preparation of vinyl polymer (a1-2) having two hydroxyl groups at one end In a four-necked flask equipped with a thermometer, stirrer, reflux condenser and nitrogen inlet tube, 700 parts by mass of methyl ethyl ketone 291 parts by weight of cyclohexyl methacrylate, 8.7 parts by weight of 3-mercapto-1,2-propanediol, and 0.15 parts by weight of 2,2′-azobis (2-methylpropionitrile) in the reaction vessel. A solvent solution of a vinyl polymer (a1-2) having two hydroxyl groups at one end with a number average molecular weight of 3,000 was obtained by supplying a part and reacting.

[Preparation Example 3] Preparation of vinyl polymer (a1-3) having two hydroxyl groups at one end In a four-necked flask equipped with a thermometer, a stirrer, a reflux condenser and a nitrogen inlet tube, 700 parts by mass of methyl ethyl ketone Then, 233 parts by mass of methyl methacrylate, 58 parts by mass of 2-ethylhexyl acrylate, 8.7 parts by mass of 3-mercapto-1,2-propanediol and 2,2′-azobis (2-methyl) were added to the reaction vessel. By supplying 0.15 parts by mass of propionitrile) and reacting it, a solvent solution of a vinyl polymer (a1-3) having two hydroxyl groups at one end with a number average molecular weight of 3,000 was obtained.

[Preparation Example 4] Preparation of vinyl polymer (a1-4) having two hydroxyl groups at one end In a four-necked flask equipped with a thermometer, a stirrer, a reflux condenser and a nitrogen inlet tube, 700 parts by mass of methyl ethyl ketone Then, 276 parts by weight of methyl (meth) acrylate, 15 parts by weight of 2-ethylhexyl acrylate, 8.7 parts by weight of 3-mercapto-1,2-propanediol and 2,2′-azobis (2 -Methylpropionitrile) A solvent solution of vinyl polymer (a1-4) having two hydroxyl groups at one end with a number average molecular weight of 3,000 was obtained by supplying 0.15 parts by mass and reacting them. .

[Comparative Preparation Example 1] Preparation of vinyl polymer (a1'-1) having two hydroxyl groups in the molecular chain Methyl ethyl ketone was added to a four-necked flask equipped with a thermometer, stirrer, reflux condenser and nitrogen inlet tube. 700 parts by mass were charged, and then 261 parts by mass of methyl (meth) acrylate, 22 parts by mass of 2-hydroxyethyl methacrylate, 17 parts by mass of 1-dodecanethiol, and 2,2′-azobis (2-methylpropio) in the reaction vessel Nitrile) By supplying 0.15 parts by mass and reacting, a solvent solution of a vinyl polymer (a1′-1) having two hydroxyl groups in a molecular chain having a number average molecular weight of 3,000 was obtained.

[Example 1]
In a nitrogen-substituted container equipped with a thermometer, a nitrogen gas introduction tube, and a stirrer, 286 parts by mass of the solvent solution of the vinyl polymer (a1-1) obtained in Preparation Example 1 and polyoxytetramethylene glycol ( (Number average molecular weight 2,000) 93 parts by mass, 35 parts by mass of 2,2-dimethylolpropionic acid and 72 parts by mass of isophorone diisocyanate are reacted at 80 ° C. for 10 hours in the presence of 84 parts by mass of methyl ethyl ketone as an organic solvent. Thus, an organic solvent solution of polyurethane (acid value 50) having a weight average molecular weight of 45,000 was obtained.

  Next, by adding 30 parts by mass of a 48% by mass aqueous potassium hydroxide solution to the polyurethane organic solvent solution, part or all of the carboxyl groups of the polyurethane are neutralized, and 685 parts by mass of water are further added and sufficiently stirred. As a result, an aqueous dispersion of polyurethane was obtained.

  Next, the aqueous dispersion of polyurethane was desolvated, and further adjusted by adding water so that the nonvolatile content was 25% by mass, thereby obtaining the binder for inkjet printing ink of the present invention.

[Example 2]
In a nitrogen-substituted container equipped with a thermometer, a nitrogen gas inlet tube, and a stirrer, 286 parts by mass of the solvent solution of the vinyl polymer (a1-2) obtained in Preparation Example 2 and polyoxytetramethylene glycol ( (Number average molecular weight 2,000) 93 parts by mass, 35 parts by mass of 2,2-dimethylolpropionic acid and 72 parts by mass of isophorone diisocyanate are reacted at 80 ° C. for 10 hours in the presence of 84 parts by mass of methyl ethyl ketone as an organic solvent. Thus, an organic solvent solution of polyurethane (acid value 50) having a weight average molecular weight of 46,000 was obtained.

  Next, by adding 30 parts by mass of a 48% by mass aqueous potassium hydroxide solution to the polyurethane organic solvent solution, part or all of the carboxyl groups of the polyurethane are neutralized, and 685 parts by mass of water are further added and sufficiently stirred. As a result, an aqueous dispersion of polyurethane was obtained.

  Next, the aqueous dispersion of polyurethane was desolvated, and further adjusted by adding water so that the nonvolatile content was 25% by mass, thereby obtaining the binder for inkjet printing ink of the present invention.

[Example 3]
In a nitrogen-substituted container equipped with a thermometer, a nitrogen gas introduction tube, and a stirrer, 10 parts by mass of the solvent solution of the vinyl polymer (a1-1) obtained in Preparation Example 1 and polyoxytetramethylene glycol ( (Number average molecular weight 2,000) 172 parts by mass, 35 parts by mass of 2,2-dimethylolpropionic acid and 76 parts by mass of isophorone diisocyanate are reacted at 80 ° C. for 10 hours in the presence of 277 parts by mass of methyl ethyl ketone as an organic solvent. Thus, an organic solvent solution of polyurethane (acid value 50) having a weight average molecular weight of 46,000 was obtained.

  Next, by adding 30 parts by mass of a 48% by mass aqueous potassium hydroxide solution to the polyurethane organic solvent solution, part or all of the carboxyl groups of the polyurethane are neutralized, and 685 parts by mass of water are further added and sufficiently stirred. As a result, an aqueous dispersion of polyurethane was obtained.

  Next, the aqueous dispersion of polyurethane was desolvated, and further adjusted by adding water so that the nonvolatile content was 25% by mass, thereby obtaining the binder for inkjet printing ink of the present invention.

[Example 4]
In a nitrogen-substituted container equipped with a thermometer, a nitrogen gas introduction tube, and a stirrer, 571 parts by mass of the solvent solution of the vinyl polymer (a1-1) obtained in Preparation Example 1 and polyoxytetramethylene glycol ( A polyurethane having a weight average molecular weight of 44,000 is obtained by reacting 11 parts by weight of a number average molecular weight of 2,000), 35 parts by weight of 2,2-dimethylolpropionic acid and 68 parts by weight of isophorone diisocyanate at 80 ° C. for 10 hours. An organic solvent solution having an acid value of 50) was obtained.

  Next, by adding 30 parts by mass of a 48% by mass aqueous potassium hydroxide solution to the polyurethane organic solvent solution, part or all of the carboxyl groups of the polyurethane are neutralized, and 685 parts by mass of water are further added and sufficiently stirred. As a result, an aqueous dispersion of polyurethane was obtained.

  Next, the aqueous dispersion of polyurethane was desolvated, and further adjusted by adding water so that the nonvolatile content was 25% by mass, thereby obtaining the binder for inkjet printing ink of the present invention.

[Example 5]
In a nitrogen-substituted container equipped with a thermometer, a nitrogen gas introduction tube, and a stirrer, 286 parts by mass of the solvent solution of the vinyl polymer (a1-1) obtained in Preparation Example 1 and 1,6-hexanediol Methyl ethyl ketone as an organic solvent 84 parts by weight of polycarbonate polyol (number average molecular weight 2,000) 93 parts by weight, 35 parts by weight of 2,2-dimethylolpropionic acid and 72 parts by weight of isophorone diisocyanate By reacting at 80 ° C. for 10 hours in the presence of part by mass, an organic solvent solution of polyurethane (acid value 50) having a weight average molecular weight of 45,000 was obtained.

  Next, by adding 30 parts by mass of a 48% by mass aqueous potassium hydroxide solution to the polyurethane organic solvent solution, part or all of the carboxyl groups of the polyurethane are neutralized, and 685 parts by mass of water are further added and sufficiently stirred. As a result, an aqueous dispersion of polyurethane was obtained.

[Example 6]
In a nitrogen-substituted container equipped with a thermometer, a nitrogen gas inlet tube, and a stirrer, 296 parts by mass of the solvent solution of the vinyl polymer (a1-1) obtained in Preparation Example 1 and polyoxytetramethylene glycol ( (Number average molecular weight 2,000) 156 parts by mass, 2,2-dimethylolpropionic acid 11 parts by mass and isophorone diisocyanate 41 parts by mass are reacted at 80 ° C. for 10 hours in the presence of 87 parts by mass of methyl ethyl ketone as an organic solvent. Thus, an organic solvent solution of polyurethane (acid value 15) having a weight average molecular weight of 45,000 was obtained.

  Next, 9 parts by weight of a 48% by weight aqueous potassium hydroxide solution is added to the polyurethane organic solvent solution to neutralize part or all of the carboxyl groups of the polyurethane, and 695 parts by weight of water are further added and stirred sufficiently. As a result, an aqueous dispersion of polyurethane was obtained.

  Next, the aqueous dispersion of polyurethane was desolvated, and further adjusted by adding water so that the nonvolatile content was 25% by mass, thereby obtaining the binder for inkjet printing ink of the present invention.

[Example 7]
In a nitrogen-substituted container equipped with a thermometer, a nitrogen gas introduction tube, and a stirrer, 286 parts by mass of the solvent solution of the vinyl polymer (a1-1) obtained in Preparation Example 1 and polyoxytetramethylene glycol ( (Number average molecular weight 2,000) 93 parts by mass, 35 parts by mass of 2,2-dimethylolpropionic acid and 72 parts by mass of isophorone diisocyanate are reacted at 80 ° C. for 10 hours in the presence of 84 parts by mass of methyl ethyl ketone as an organic solvent. Thus, an organic solvent solution of polyurethane (acid value 50) having a weight average molecular weight of 100,000 was obtained.

  Next, by adding 30 parts by mass of a 48% by mass aqueous potassium hydroxide solution to the polyurethane organic solvent solution, part or all of the carboxyl groups of the polyurethane are neutralized, and 685 parts by mass of water are further added and sufficiently stirred. As a result, an aqueous dispersion of polyurethane was obtained.

  Next, the aqueous dispersion of polyurethane was desolvated, and further adjusted by adding water so that the nonvolatile content was 25% by mass, thereby obtaining the binder for inkjet printing ink of the present invention.

[Example 8]
In a nitrogen-substituted container equipped with a thermometer, a nitrogen gas introduction tube, and a stirrer, 286 parts by mass of the solvent solution of the vinyl polymer (a1-3) obtained in Preparation Example 1 and polyoxytetramethylene glycol ( (Number average molecular weight 2,000) 93 parts by mass, 35 parts by mass of 2,2-dimethylolpropionic acid and 72 parts by mass of isophorone diisocyanate are reacted at 80 ° C. for 10 hours in the presence of 84 parts by mass of methyl ethyl ketone as an organic solvent. Thus, an organic solvent solution of polyurethane (acid value 50) having a weight average molecular weight of 45,000 was obtained.

  Next, by adding 30 parts by mass of a 48% by mass aqueous potassium hydroxide solution to the polyurethane organic solvent solution, part or all of the carboxyl groups of the polyurethane are neutralized, and 685 parts by mass of water are further added and sufficiently stirred. As a result, an aqueous dispersion of polyurethane was obtained.

  Next, the aqueous dispersion of polyurethane was desolvated, and further adjusted by adding water so that the nonvolatile content was 25% by mass, thereby obtaining the binder for inkjet printing ink of the present invention.

[Example 9]
In a nitrogen-substituted container equipped with a thermometer, a nitrogen gas introduction tube, and a stirrer, 286 parts by mass of the solvent solution of the vinyl polymer (a1-4) obtained in Preparation Example 1 and polyoxytetramethylene glycol ( (Number average molecular weight 2,000) 93 parts by mass, 35 parts by mass of 2,2-dimethylolpropionic acid and 72 parts by mass of isophorone diisocyanate are reacted at 80 ° C. for 10 hours in the presence of 84 parts by mass of methyl ethyl ketone as an organic solvent. Thus, an organic solvent solution of polyurethane (acid value 50) having a weight average molecular weight of 45,000 was obtained.

  Next, by adding 30 parts by mass of a 48% by mass aqueous potassium hydroxide solution to the polyurethane organic solvent solution, part or all of the carboxyl groups of the polyurethane are neutralized, and 685 parts by mass of water are further added and sufficiently stirred. As a result, an aqueous dispersion of polyurethane was obtained.

  Next, the aqueous dispersion of polyurethane was desolvated, and further adjusted by adding water so that the nonvolatile content was 25% by mass, thereby obtaining the binder for inkjet printing ink of the present invention.

[Example 10]
In a nitrogen-substituted container equipped with a thermometer, a nitrogen gas introduction tube, and a stirrer, 286 parts by mass of the solvent solution of the vinyl polymer (a1-1) obtained in Preparation Example 1 and polyoxypropylene glycol (several By reacting 93 parts by weight of an average molecular weight of 2,000), 35 parts by weight of 2,2-dimethylolpropionic acid and 72 parts by weight of isophorone diisocyanate at 80 ° C. for 10 hours in the presence of 84 parts by weight of methyl ethyl ketone as an organic solvent. An organic solvent solution of polyurethane (acid value 50) having a weight average molecular weight of 18,000 was obtained.

  Next, by adding 30 parts by mass of a 48% by mass aqueous potassium hydroxide solution to the polyurethane organic solvent solution, part or all of the carboxyl groups of the polyurethane are neutralized, and 685 parts by mass of water are further added and sufficiently stirred. As a result, an aqueous dispersion of polyurethane was obtained.

  Next, the aqueous dispersion of polyurethane was desolvated, and further adjusted by adding water so that the nonvolatile content was 25% by mass, thereby obtaining the binder for inkjet printing ink of the present invention.

[Comparative Example 1]
In a nitrogen-substituted container equipped with a thermometer, a nitrogen gas introduction tube, and a stirrer, 174 parts by mass of polyoxytetramethylene glycol (number average molecular weight 2,000), 35 parts by mass of 2,2-dimethylolpropionic acid, and By reacting 76 parts by mass of isophorone diisocyanate at 80 ° C. for 10 hours in the presence of 284 parts by mass of methyl ethyl ketone as an organic solvent, an organic solvent solution of polyurethane (acid value 50) having a weight average molecular weight of 46,000 was obtained. .

  Next, by adding 30 parts by mass of a 48% by mass aqueous potassium hydroxide solution to the polyurethane organic solvent solution, part or all of the carboxyl groups of the polyurethane are neutralized, and 685 parts by mass of water are further added and sufficiently stirred. As a result, an aqueous dispersion of polyurethane was obtained.

  Subsequently, the aqueous dispersion of polyurethane was desolvated, and further adjusted by adding water so that the nonvolatile content was 25% by mass, thereby obtaining a binder for inkjet printing ink.

[Comparative Example 2]
In a nitrogen-substituted container equipped with a thermometer, a nitrogen gas introduction tube, and a stirrer, 611 parts by mass of the solvent solution of the vinyl polymer (a1-1) obtained in Preparation Example 1 and 2,2-dimethylol By reacting 35 parts by mass of propionic acid and 68 parts by mass of isophorone diisocyanate at 80 ° C. for 10 hours, an organic solvent solution of polyurethane (acid value 50) having a weight average molecular weight of 44,000 was obtained.

  Next, by adding 30 parts by mass of a 48% by mass aqueous potassium hydroxide solution to the polyurethane organic solvent solution, part or all of the carboxyl groups of the polyurethane are neutralized, and 685 parts by mass of water are further added and sufficiently stirred. As a result, an aqueous dispersion of polyurethane was obtained.

  Subsequently, the aqueous dispersion of polyurethane was desolvated, and further adjusted by adding water so that the nonvolatile content was 25% by mass, thereby obtaining a binder for inkjet printing ink.

[Comparative Example 3]
As in Example 1, except that 286 parts by mass of the solvent solution of the vinyl polymer (a1-3) obtained in Comparative Preparation Example 3 was used instead of the solvent solution of the vinyl polymer (a1-1). Thus, a binder for ink jet printing ink having a nonvolatile content of 25% by mass was obtained.

[Measurement of weight average molecular weight]
The weight average molecular weight of the polyurethane (C) was measured by gel permeation chromatograph (GPC method). Specifically, polyurethane (C) was coated on a glass plate with a 3 mil applicator and dried at room temperature for 1 hour to prepare a semi-dry coating film. The obtained coating film was peeled off from the glass plate, and 0.4 g was dissolved in 100 g of tetrahydrofuran to obtain a measurement sample.

  As a measuring apparatus, Tosoh Corporation high performance liquid chromatograph HLC-8220 type was used. As a column, Tosoh Corporation column TSK-GEL (HXL-H, G5000HXL, G4000HXL, G3000HXL, G2000HXL) was used in combination.

  Standard polystyrenes (manufactured by Showa Denko KK and Toyo Soda Co., Ltd.) as standard samples (molecular weights: 44.48 million, 4250,000, 288,000, 2750,000, 1.85 million, 860,000, 450,000, 411,000, 35. Calibration curves were created using 50,000, 190,000, 160,000, 96,000, 50,000, 37,000, 198,000, 196,000, 5570, 4000, 2980, 2030, 500). .

  Tetrahydrofuran was used as the eluent and sample solution, and the weight average molecular weight was measured using an RI detector with a flow rate of 1 mL / min, a sample injection amount of 500 μL, and a sample concentration of 0.4 mass%.

Preparation Example 4 (Aqueous dispersion of quinacridone pigment)
1500 g of vinyl polymer (styrene / acrylic acid / methacrylic acid = 77/10/13 (mass ratio), weight average molecular weight 11,000, acid value 156 mgKOH / g), quinacridone pigment (chromoftal jet magenta 4630 g of DMQ (manufactured by Ciba Specialty Chemicals), 380 g of phthalimidomethylated 3,10-dichloroquinacridone (average number of phthalimidomethyl groups per molecule is 1.4), 2600 g of diethylene glycol, and 34% by mass potassium hydroxide 688 g of the aqueous solution was charged into a 50 L capacity planetary mixer PLM-V-50V (manufactured by Inoue Seisakusho Co., Ltd.), and kneading was continued for 4 hours.

  A total amount of 8000 g of ion-exchanged water heated to 60 ° C. was added in 2 hours to obtain a colored resin composition having a nonvolatile content of 37.9% by mass.

  While adding 744 g of diethylene glycol and 7380 g of ion-exchanged water little by little to 12 kg of the colored resin composition obtained by the above method, the mixture was stirred with a dispersion stirrer, and a precursor of an aqueous dispersion of quinacridone pigment (before dispersion treatment). An aqueous dispersion) was obtained.

  Next, 18 kg of this aqueous dispersion precursor was added to a bead mill (Nanomill NM-G2L manufactured by Asada Tekko Co., Ltd., beads φ: 0.3 mm zirconia beads, bead filling amount: 85%, cooling water temperature: 10 ° C., rotation The aqueous dispersion of the quinacridone pigment was obtained by subjecting the solution passed through the bead mill to a centrifugal treatment of 13000 G × 10 minutes, followed by filtration through a filter having an effective pore size of 0.5 μm. Got. The concentration of the quinacridone pigment in this aqueous dispersion was 14.9% by mass.

[Preparation of ink for inkjet printing]
In the preparation example 4 and the binder for the inkjet printing ink obtained in Examples 1 to 10 and Comparative Examples 1 to 3 so that the concentration of the quinacridone pigment is 4% by mass and the concentration of the polyurethane is 1% by mass. The following water-based pigment dispersion of the obtained quinacridone pigment, 2-pyrrolidinone, triethylene glycol monobutyl ether, glycerin, surfactant (Surfinol 440, manufactured by Air Products) and ion-exchanged water are blended in the following proportions: Ink jet printing ink was prepared by mixing and stirring according to the following.

(Mixing ratio of ink for inkjet printing)
-Aqueous dispersion of quinacridone pigment obtained in Preparation Example 4 (pigment concentration: 14.9% by mass); 26.8 g
・ 2-Pyrrolidinone; 8.0g
・ Triethylene glycol monobutyl ether; 8.0 g
・ Glycerin; 3.0g
・ Surfactant (Surfinol 440, manufactured by Air Products); 0.5 g
・ Ion exchange water: 48.7 g
-Binder for inkjet printing inks obtained in Examples 1 to 10 and Comparative Examples 1 to 3 (nonvolatile content: 25% by mass); 4.0 g

[Evaluation of storage stability of ink for inkjet printing]
Evaluation was performed based on the viscosity of the ink for inkjet printing obtained above and the particle size of dispersed particles in the ink. The viscosity measurement was performed using VISCOMETER TV-22 manufactured by Toki Sangyo Co., Ltd., and the particle diameter was measured using Microtrac UPA EX150 manufactured by Nikkiso Co., Ltd.

  Next, after sealing the ink in a glass container such as a screw tube and performing a heating test for 4 weeks in a thermostat at 70 ° C., the viscosity of the ink and the particle diameter of the dispersed particles in the ink are as follows: It measured by the method similar to the above.

  Changes in the viscosity and particle diameter after the heating test with respect to the viscosity and particle diameter of the ink before the heating test were calculated based on the following formulas, respectively, and the storage stability of the pigment ink was evaluated.

(Formula I)
[{(Particle size of dispersed particles in ink after heating test) − (Particle size of dispersed particles in ink before heating test)} / (Particle size of dispersed particles in ink before heating test)] × 100

[Criteria]
○: Change rate of particle size is less than 5% Δ: Change rate of particle size is 5% or more and less than 10% ×: Change rate of particle size is 10% or more

(Formula II)
[{(Ink viscosity after heating test) − (Ink viscosity before heating test)} / (Ink viscosity before heating test)] × 100

[Criteria]
○: Viscosity change rate is less than 2% Δ: Viscosity change rate is 2% or more and less than 5% ×: Viscosity change rate is 5% or more

[Evaluation of ink ejection stability]
A diagnostic page was printed and the state of the nozzle was confirmed with a Photomart D5360 (manufactured by Hewlett-Packard Company) in which a black ink cartridge was filled with the inkjet pigment ink. After continuously printing 20 pages of solid print with a print density setting of 100% in an area of 18 cm × 25 cm per page, a diagnostic page was printed again to check the state of the nozzles. The change in the state of the nozzle before and after continuous solid printing was evaluated as the ink ejection property. The evaluation criteria are described below.

[Criteria]
◎: No change in nozzle state and no discharge abnormality occurred ○: Although slight ink adhesion to the nozzle was confirmed, no abnormality in ink discharge direction occurred △: Solid Abnormal ink ejection direction or non-ejection of ink occurred after printing 20 pages continuously ×: Abnormal ink ejection direction or non-ejection of ink occurred during printing. What could not be printed

[Printing performance evaluation of pigment ink for inkjet printing]
(Glossy)
Using the commercially available thermal jet ink jet printer (Photomart D5360; manufactured by Hewlett Packard) on the printing surface of photographic paper (glossy) [HP Advanced Photo Paper manufactured by Hewlett Packard Company] which is a dedicated paper for inkjet printing, the pigment ink Was filled in a black ink cartridge, and solid printing was performed with a print density setting of 100%.

  After leaving the printed matter obtained above at room temperature for 24 hours, the gloss of 20 arbitrary degrees of the gloss of the printed matter was measured using a micro haze plus (manufactured by Toyo Seiki Seisakusho Co., Ltd.), and the average value thereof Was calculated.

(Abrasion resistance)
Using a commercially available thermal jet ink jet printer (Photomart D5360; manufactured by Hewlett Packard) on the printing surface of photographic printing paper (glossy) [HP Advanced Photo Paper manufactured by Hewlett Packard], the pigment ink is applied to a black ink cartridge. An evaluation printed matter was obtained by filling and performing solid printing with a print density setting of 100%.

  After the printed matter for evaluation was dried at room temperature for 10 minutes, the printed surface was scratched with a nail under a load of about 5 kg, and the rubbing condition of the color and the like of the printed surface was visually evaluated according to the following evaluation criteria. In addition, since the ejection stability of the ink was insufficient, those for which the printed matter for evaluation could not be obtained are described as “not printable” in the table.

[Criteria]
A: There was no scratch on the printed surface, and no peeling of the coloring material was observed.
B: Although some scratches were generated on the printed surface, there was no problem in practical use, and no peeling of the coloring material was observed.
C: Some scratches were generated on the printed surface, and peeling of the coloring material was observed.
D: Significant scratches were generated in the range of about 50% or more of the printed surface, and peeling of the coloring material was observed.

(Alkali resistance)
After the printed matter for evaluation was dried at room temperature for 3 minutes, 3 drops of 0.5% by weight aqueous KOH solution was dropped onto the printed surface with a dropper, and the printed surface was rubbed with a finger after 10 seconds. Was visually evaluated. The evaluation criteria are described below. In addition, since the ejection stability of the ink was insufficient, those for which the printed matter for evaluation could not be obtained are described as “not printable” in the table.

[Criteria]
A: No peeling of coloring material or the like was observed on the printed surface, and no discoloration of the printed surface was observed.
B: Although peeling of the color material or the like was not observed on the printed surface, the printed surface was slightly discolored.
C: Some peeling of the coloring material or the like occurred on the printing surface, and discoloration of the printing surface also occurred.
D: Remarkable peeling of the color material or the like occurred over a range of about 50% or more of the printed surface, and discoloration of the printed surface also occurred.

Abbreviations in Tables 1 to 3 are described below.
“PTMG”: polyoxytetramethylene glycol (number average molecular weight 2,000)
“DMPA”; 2,2-dimethylolpropionic acid “IPDI”; isophorone diisocyanate “PC”; polycarbonate polyol obtained by reacting 1,6-hexanediol and methyl carbonate (number average molecular weight 2,000)
"PPG; polyoxypropylene glycol (number average molecular weight 2,000)

Claims (9)

A vinyl polymer (a1) having a functional group (X) represented by the following general formula (I) and having two hydroxyl groups at one end, polyether polyol, polyester polyol, polyester ether polyol and polycarbonate polyol A structure derived from a vinyl polymer (a1) in the side chain, obtained by reacting a polyol (A) containing at least one polyol (a2) selected from the group consisting of: and a polyisocyanate (B). A binder for inkjet printing inks, characterized in that the polyurethane (C) having a water content is dispersed in an aqueous medium (D).

[R in General Formula (I) represents an aliphatic alkyl group, an alicyclic alkyl group or an aromatic structure having 4 or more carbon atoms. ] The polyurethane (C) is obtained by using the vinyl polymer (a1) in the range of 1% by mass to 65% by mass with respect to the total mass of raw materials used for the production of the polyurethane (C). The binder for ink-jet printing ink according to claim 1. The polyurethane (C) is obtained by using the polyol (a2) in the range of 5% by mass to 80% by mass with respect to the total mass of raw materials used for the production of the polyurethane (C). Item 2. A binder for ink jet printing ink according to Item 1. The vinyl polymer (a1) has a chain transfer agent (E) having two hydroxyl groups and one mercapto group, and an aliphatic alkyl group or alicyclic alkyl group having 4 or more carbon atoms ( The binder for ink-jet printing ink according to claim 1, which is obtained by reacting a vinyl monomer (F) containing a (meth) acrylic acid alkyl ester. The vinyl monomer (F) is a total of (meth) acrylic acid alkyl esters having an aliphatic alkyl group or alicyclic alkyl group having 4 or more carbon atoms, based on the total amount of the vinyl monomer (F). The binder for ink-jet printing ink according to claim 1, comprising 5% by mass to 100% by mass. Ink for inkjet printing containing the binder for inkjet printing inks in any one of Claims 1-5, and a pigment or dye. The ink for inkjet printing containing the binder for inkjet printing inks of any one of Claims 1-5, a pigment or dye, and an acrylic resin or an acryl-styrene resin. A printed matter printed with the ink jet printing ink according to claim 6 or 7. The inkjet printing ink binder according to any one of claims 1 to 5, and an aqueous pigment dispersion in which a pigment is dispersed in an aqueous medium with an acrylic resin or an acrylic-styrene resin. A method for producing printing ink.