JP2011140560A - Water-based urethane resin composition, binder for ink comprising the same, binder for inkjet printing ink, inkjet printing ink, and printed matter printed with the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a water-based urethane resin composition which can be used for producing ink that can form a printed image with very high levels of scrape resistance and chemical resistance and is excellent in preservation stability such as an ink drying property or an ink discharge stability; to provide a binder for ink, comprising it; to provide a binder for inkjet printing ink; and to provide inkjet printing ink. <P>SOLUTION: The water-based urethane resin composition includes: an urethane resin (A) having an anionic group (a1) and a polyalkylene oxide chain (a2) in a side chain; and a water-based medium, to the binder for ink comprising it, to the binder for inkjet printing ink, and to the inkjet printing ink. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a water-based urethane resin composition that can be used for various applications such as a coating agent and an adhesive, as well as an ink binder used in, for example, ink jet printing.

  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 shifting from conventional dye inks to pigment inks and shifting from solvent-based to water-based inks. Development based on water-based pigment ink is being actively carried out.

  In addition, various performances of the ink are required year by year as the performance of ink jet printers and the like increases. For example, a level of abrasion resistance that can prevent deterioration of the printed image due to missing pigment, which may occur when an external force such as friction is applied to the surface of the printed image without impairing storage stability such as ink ejection properties. In recent years, there has been a strong demand for chemical resistance at a level that does not cause bleeding or discoloration of a printed image even when a cleaning agent such as a glass cleaner adheres to the surface of the printed image.

  Examples of the ink excellent in scratch resistance include an ink for inkjet recording containing a pigment, an aqueous resin, and an aqueous medium, wherein the aqueous resin reacts with an organic diisocyanate and a diol having a polyoxyethylene structure. There is known an ink for inkjet recording, wherein the 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. (For example, refer to 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 for ink jet recording sometimes causes ink to float or bleed when an alkaline cleaning agent or the like adheres to the surface.

  On the other hand, ink-jet printing inks are required to have a quicker drying property of the ink in addition to the ink ejection stability, scratch resistance and the like as the printing speed of the printer increases. The ink drying property is a property that allows the solvent contained in the ink to quickly penetrate into the recording medium when the ink is ejected onto the recording medium by an ink jet printer or the like. It refers to the property that even if it is rubbed lightly with a finger or the like, it does not cause bleeding of the printed image or spreading of the ink. In order to improve the drying property of the ink, it is necessary to improve the recording medium to be used, but it is also essential to improve not only the recording medium but also the ink surface.

  Here, when printing is performed on a recording medium using the inkjet recording ink described in Patent Document 1, the permeability of the solvent contained in the ink into the recording medium is good to some extent, It did not have a level of dryness that was compatible with high-speed printing in recent years.

JP 2000-1639 A

  The problem to be solved by the present invention is to provide a water-based urethane resin composition that can form a film having a very high level of scratch resistance and chemical resistance, and is excellent in drying and storage stability. It is.

  In addition, the problem to be solved by the present invention is that a printed image having a very high level of scratch resistance and chemical resistance can be formed, and storage stability such as ink drying property and ink ejection stability can be obtained. It is an object to provide an aqueous urethane resin composition that can be used in the production of an ink having excellent properties, and an ink binder, an ink jet printing ink binder, an ink jet printing ink, and a printed matter containing the same.

  The present inventors examined increasing the hydrophilicity of the aqueous urethane resin composition as a method for improving the drying property.

  Specifically, a water-based urethane resin composition in which a polyether polyol such as polyoxyethylene glycol was used as a polyol used for producing a urethane resin and an ethylene oxide chain was introduced into the main chain was examined.

  If it is the said water-based urethane resin composition, although dryness, such as a printing image and a film, has improved a little, it cannot be said that it is still enough, and the film | membrane and printing image which are formed, and abrasion resistance and chemical resistance Sex was not a step closer to practical use.

  Therefore, the present inventors can further improve the hydrophilicity of the urethane resin by introducing the polyethylene oxide chain or the like into the side chain of the urethane resin, and as a result, the drying property may be improved. I thought and proceeded with the study.

  Specifically, the use of a diol having a polyalkylene oxide chain in the side chain was examined as a polyol used for the production of a urethane resin.

  Although it has been found that by using a urethane resin composition having a polyalkylene oxide chain in the side chain, the drying property, scratch resistance and chemical resistance can be improved to some extent, the required level has not been reached one step further.

  Therefore, in order to further increase the degree of hydrophilicity of the urethane resin, a urethane resin-containing composition into which a conventionally known anionic group or cationic group was introduced instead of the polyalkylene oxide chain was studied.

  However, the composition does not have a satisfactory level of drying properties, and the scratch resistance and chemical properties are low as compared to the case where the urethane resin composition having the polyalkylene oxide chain is used. It was a thing.

  However, when the anionic group and the polyalkylene oxide chain are used in combination as the hydrophilic group in the urethane resin and the polyalkylene oxide chain is introduced into the side chain of the urethane resin, such a urethane resin composition can be used. For example, it has been found that a very high level of dryness, scratch resistance, and chemical resistance can be achieved without impairing storage stability such as ejection stability.

  That is, the present invention includes an aqueous urethane resin composition comprising an urethane resin (A) having an anionic group (a1) and a polyalkylene oxide chain (a2) in the side chain and an aqueous medium, and The present invention relates to a binder for ink jet printing ink containing the same.

  The present invention also relates to an ink for ink jet printing comprising the above ink jet printing ink binder and a pigment or dye, and a printed matter printed using the ink.

  The water-based urethane resin composition of the present invention can be used for various coating agents and adhesives because it can form a film having excellent storage stability and drying properties and excellent scratch resistance and chemical resistance.

  Further, according to the aqueous urethane resin composition of the present invention, the ink can be obtained without impairing the excellent ink ejection stability and the excellent scratch resistance and chemical resistance (particularly alkali resistance) of the printed image to be formed. Therefore, it can be used exclusively as an ink binder, and in particular, can be used as an ink jet printing ink binder.

  In addition, the water-based urethane resin composition is also excellent in ink drying properties, so that, for example, even when a printer with a large ink discharge amount such as an industrial wide format printer is used, its production efficiency is lowered. In addition, it can be used for forming a printed image having high clarity and excellent scratch resistance.

  The present invention relates to a urethane resin (A) having an anionic group (a1) and a polyalkylene oxide chain (a2) in the side chain, an aqueous medium (B), and an aqueous urethane resin containing other components as required. It is a composition.

  The urethane resin (A) can be stably dissolved or dispersed in the aqueous medium (B) by the anionic group (a1) and the polyalkylene oxide chain (a2). Therefore, if it is the water-based urethane resin composition of this invention, even if it is a case where it is a case where it is used for the binder of the ink for inkjet printing, it is hard to clog an ink discharge nozzle.

  The aqueous urethane resin composition of the present invention has an average particle size in the range of 10 to 350 nm from the viewpoint of maintaining good storage stability and ink ejection stability when used as a binder for inkjet printing inks. It is preferable that the particles of the urethane resin (A) to be dispersed are dispersed in the aqueous medium (B).

  In the present invention, it is essential to use a urethane resin (A) having a combination of an anionic group (a1) and a polyalkylene oxide chain (a2). Here, when a urethane resin having only one of the hydrophilic groups is used instead of the urethane resin (A), it is difficult to achieve both dryness, scratch resistance and chemical resistance. .

  In the present invention, it is essential to use the urethane resin (A) in which the polyalkylene oxide chain (a2) is present in the side chain of the urethane resin constituting the main chain. Here, even if a urethane resin in which the polyalkylene oxide structure is present in the main chain of the urethane resin is used in place of the urethane resin (A), a satisfactory level of drying cannot be achieved, and Scratch resistance and chemical resistance are also not practically sufficient levels.

  In addition, when a urethane resin in which the polyalkylene oxide chain (a2) is present at the end of the urethane resin is used instead of the urethane resin (A), sufficient drying properties cannot be achieved.

  The urethane resin (A) preferably has the anionic group (a1) in the range where the acid value is 20 to 100 in order to impart excellent scratch resistance and chemical resistance.

  Further, as the urethane resin (A), it is preferable to use a resin having 1 to 60% by mass of the polyalkylene oxide chain (a2) with respect to the total amount of the urethane resin (A). It is preferable in order to achieve both compatibility and chemical resistance.

  As the urethane resin (A), a resin having a mass ratio [(a1) / (a2)] between the anionic group (a1) and the polyalkylene oxide chain (a2) of 0.06 to 30 is used. It is preferable to achieve both dryness, scratch resistance and chemical resistance.

  As the anionic group (a1), 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 is neutralized with a basic compound or the like. It is preferable to use a rate group or a sulfonate group in order to maintain good water dispersion stability.

  Examples of basic compounds that can be used for neutralization of the anionic group include organic amines such as ammonia, triethylamine, pyridine, morpholine, alkanolamines such as monoethanolamine, Na, K, Li, and Ca. A metal base compound etc. are mentioned.

  The polyalkylene oxide chain (a2) includes polyoxyethylene group, polyoxypropylene group, polyoxybutylene group, poly (oxyethylene-oxypropylene) group, polyoxyethylene-polyoxypropylene group, and other polyoxyethylene groups. Oxyalkylene groups can be used. Among these, a polyethylene oxide chain is preferable for improving the drying property, and it is preferable to use a polyethylene oxide chain having a repeating unit of 5 to 40 in the ethylene oxide structure for drying property, scratch resistance and chemical resistance. It is preferable in order to balance the properties.

  Further, as the urethane resin (A) used in the present invention, for example, those having a weight average molecular weight of 3000 to 150,000 are preferably used, and those having a weight average molecular weight of 15000 to 50000 are preferably used for inkjet. It is preferable for obtaining excellent scratch resistance and chemical resistance in printed matter as well as good storage stability, ink ejection stability and ink drying property of printing ink.

  As said urethane resin (A), what is obtained by making a polyol (B) and polyisocyanate (C) react can be used. Here, as the polyol (B), an anionic group-containing polyol (b1) is preferably used from the viewpoint of introducing an anionic group into the urethane resin (A).

  Moreover, it is preferable to use the polyol (b2) which has a polyalkylene oxide chain in a side chain from the viewpoint of introducing a polyalkylene oxide chain into the side chain of the urethane resin (A) as the polyol (B).

  Examples of the anionic group-containing polyol (b1) include 2,2′-dimethylolpropionic acid, 2,2′-dimethylolbutanoic acid, 2,2′-dimethylolbutyric acid, 2,2′-dimethylolvaleric acid, and the like. And sulfonic acid group-containing polyols such as 5-sulfoisophthalic acid, sulfoterephthalic acid, 4-sulfophthalic acid, and 5 [4-sulfophenoxy] isophthalic acid. Further, as the hydrophilic group-containing polyol, a hydrophilic group-containing polyester polyol obtained by reacting the above-described low molecular weight hydrophilic group-containing polyol with various polycarboxylic acids such as adipic acid is used. You can also.

  The anionic group-containing polyol (b1) may be used in a range of 0.5 to 30% by mass with respect to the total amount of the polyol (B) and polyisocyanate (C) used in the production of the urethane resin. preferable.

  Moreover, as a polyol which has a polyalkylene oxide chain in the side chain which can be used for the said polyol (B), it is preferable to use the polyol whose molecular weight of a polyalkylene oxide chain is about 600-3000, for example, 600-1000. More preferably, the polyol is used. Moreover, it is preferable to use the polyol whose said polyalkylene oxide chain is a polyethylene oxide chain.

  As the polyol having a polyalkylene oxide chain in the side chain, it is particularly preferable to use, for example, one sold by Perstorp under the trade name “Ymer N120”.

  The polyalkylene oxide chain of the polyol (b2) may have a copolymer structure of, for example, polyethylene oxide and polypropylene oxide.

  The polyalkylene oxide chain may be a side chain having a main chain structure such as polyester polyol, polyether polyol, and polycarbonate polyol.

  When the polyol (b2) is used in the range of 1 to 70% by mass with respect to the total amount of the polyol (B) and the polyisocyanate (C) used in the production of the urethane resin, the drying property is improved. It is preferable and 1-50 mass% is more preferable. In order to further improve the drying property, it is preferably used in the range of 10 to 50% by mass.

  Further, as the polyol (B), in addition to the anionic group-containing polyol (b1) and the polyol (b2) having a polyalkylene oxide chain in the side chain, the scratch resistance and chemical resistance of the coating film and the printed image can be obtained. From the viewpoint of further improvement, it is preferable to use the aliphatic cyclic structure-containing polyol (b3).

  Examples of the aliphatic cyclic structure-containing polyol (b3) include cyclobutanediol, cyclopentanediol, 1,4-cyclohexanediol, cycloheptanediol, cyclooctanediol, cyclohexanedimethanol, hydroxypropylcyclohexanol, dicyclohexanediol, Low molecular weight aliphatic cyclic structure-containing polyol such as butylcyclohexanediol, 1,1′-bicyclohexylidenediol, cyclohexanetriol, hydrogenated bisphenol A, 1,3-adamantanediol, etc. Or an aliphatic cyclic structure-containing polycarbonate polyol, an aliphatic cyclic structure-containing polyester polyol, or an aliphatic cyclic structure-containing polyether polyol. It can be.

  The said aliphatic cyclic structure containing polyol (b3) is used in 0.5-25 mass% with respect to the total amount of the polyol (B) and polyisocyanate (C) used for manufacture of the said urethane resin. It is preferable for imparting scratch resistance and chemical resistance, and it is more preferable to use in the range of 1 to 20% by mass in order to achieve both scratch resistance, chemical resistance and drying resistance.

  The polyol (B) is necessary in addition to the anionic group-containing polyol (b1), the polyol (b2) having a polyalkylene oxide chain in the side chain, and the aliphatic cyclic structure-containing polyol (b3). Depending on the case, other polyols can be used in combination.

  As said other polyol, polyether polyol, polycarbonate polyol, polyester polyol, etc. can be used, for example.

  Among these, the polyether polyol and the polycarbonate polyol can impart good storage stability and dischargeability of the ink when the aqueous urethane resin composition of the present invention is used as a binder for ink jet printing ink. It is preferable to use in combination with an anionic group-containing polyol (b1) or polyol (b2).

  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, neopentyl glycol, 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.

  As the polyether polyol, it is preferable to use polytetramethylene glycol, polypropylene glycol, or the like from the viewpoint of obtaining an ink-jet ink binder having excellent scratch resistance.

  As the polytetramethylene glycol or polypropylene glycol, those having a number average molecular weight of 500 to 5,000 are preferably used, and those having a number average molecular weight of 500 to 3,500 are more excellent in storage stability. And more preferable for achieving both the formed coating film and the scratch resistance of the printed image.

  When the polytetramethylene glycol or polypropylene glycol is used in the range of 30 to 95% by mass with respect to the entire polyol (B) used in the production of the urethane resin (A), the storage stability is further improved. In order to achieve both the scratch resistance of the formed film and the printed image, it is more preferable.

  Examples of the polycarbonate polyol that can be used as the other polyol include those obtained by reacting a carbonate with a polyol, and those obtained by reacting phosgene with bisphenol A or the like.

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

  Examples of the polyol that can react with the carbonate ester include ethylene glycol, diethylene glycol, 1,2-propylene glycol, dipropylene glycol, 1,4-butanediol, 1,5-pentanediol, and 3-methyl-1,5- Relatively low molecular weight dihydroxy compounds such as pentanediol, neopentyl glycol and 1,4-cyclohexanediol, polyethylene glycol, polypropylene glycol, polyester polyols such as polyhexamethylene adipate, and the like can be used.

  Examples of the polyester polyol include those obtained by esterifying low molecular weight polyols and polycarboxylic acids, polyesters obtained by ring-opening polymerization reaction of cyclic ester compounds such as ε-caprolactone, and the like. Copolyester of the above 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.

  Examples of the other polyol include a cationic group-containing polyol including a tertiary amino group-containing polyol such as N-methyl-diethanolamine, and a nonion such as a polyalkylene glycol having an ethylene oxide structure as described above in the main chain. A functional group-containing polyol or the like can also be used.

  Moreover, as polyisocyanate (C) used when manufacturing the said urethane resin (A), aromatic diisocyanates, such as phenylene diisocyanate, tolylene diisocyanate, diphenylmethane diisocyanate, naphthalene diisocyanate, hexamethylene diisocyanate, lysine diisocyanate, Aliphatic or aliphatic cyclic structure-containing diisocyanates such as cyclohexane diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, xylylene diisocyanate, tetramethylxylylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate are used alone or 2 More than one species can be used in combination. Among them, it is preferable to use an aliphatic cyclic structure-containing diisocyanate because a coating film having excellent long-term weather resistance can be formed.

  Moreover, as an aqueous medium used by this invention, the organic solvent mixed with water and water, and these mixtures are mentioned. 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.

Next, the manufacturing method of the water-based urethane resin composition of this invention is demonstrated.
First, as a method for producing the urethane resin (A), for example, a urethane prepolymer is produced by reacting the polyol (B) and the polyisocyanate (C) in the absence of a solvent or in the presence of an organic solvent. Then, a method of neutralizing an anionic group such as a carboxyl group in the urethane prepolymer as necessary and reacting with a chain extender as necessary can be mentioned.

  In the reaction of the polyol (B) and the polyisocyanate (C), for example, the equivalent ratio of the isocyanate group of the polyisocyanate (C) to the hydroxyl group of the polyol (B) is 0.8 to 2.5. Preferably, it is carried out in the range of 0.9 to 1.5. Moreover, when using the chain extender mentioned later, it is preferable that the said equivalent ratio is the range of 1.1-1.5.

  Examples of the organic solvent that can be used in producing the urethane resin (A) include ketones such as acetone and methyl ethyl ketone; ethers such as tetrahydrofuran and dioxane; acetates such as ethyl acetate and butyl acetate; Nitriles: Amides such as dimethylformamide and N-methylpyrrolidone can be used alone or in combination of two or more.

  Moreover, as a chain extender which can be used when manufacturing the said urethane resin (A), a polyamine, another active hydrogen atom containing compound, etc. 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, Diamines containing one primary amino group and one secondary amino group such as N-methylaminopropylamine; polyamines such as diethylenetriamine, dipropylenetriamine and triethylenetetramine; hydrazine, N Hydrazines such as N′-dimethylhydrazine and 1,6-hexamethylenebishydrazine; Dihydrazides such as succinic acid dihydrazide, adipic acid dihydrazide, glutaric acid dihydrazide, sebacic acid dihydrazide, and isophthalic acid dihydrazide; Semicarbazides such as 3-semicarbazide-propyl-carbazic acid ester and semicarbazide-3-semicarbazide methyl-3,5,5-trimethylcyclohexane can be 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, sorbitol; phenols such as bisphenol A, 4,4′-dihydroxydiphenyl, 4,4′-dihydroxydiphenyl ether, 4,4′-dihydroxydiphenyl sulfone, 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 in such a range that the equivalent ratio of the amino group and excess isocyanate group of the polyamine is 1.9 or less (equivalent ratio), and 0.3 to 1.0 (equivalent ratio). ) Is more preferable.

  Moreover, the urethane resin (A) used in the present invention may have a urea bond. A urea bond can be introduced into a urethane resin by a reaction between an amine having active hydrogen and an isocyanate. The urea bond is preferably in the range of 0 to 10% by mass with respect to the entire urethane resin (A).

  Examples of the method for producing the aqueous urethane resin composition of the present invention by making the urethane resin (A) produced by the above method water-based include the following methods.

  [Method 1] After neutralizing some or all of the anionic groups of the urethane prepolymer obtained by reacting the polyol (B) and the polyisocyanate (C), the aqueous medium is added and dispersed. Thereafter, the urethane resin (A) is dispersed by chain extension using the same chain extender as described above.

  [Method 2] A urethane prepolymer and a chain extender similar to those described above are charged into a reaction vessel in a batch or divided and a urethane resin (A) is produced by chain extension reaction, and then the obtained polyurethane resin A method of neutralizing part or all of the anionic group therein and then adding an aqueous medium to disperse in water.

  In [Method 1] to [Method 2], 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 urethane resin (A).

  As such a hydrophilic group-containing compound, an anionic group-containing compound, a cationic group-containing compound, an amphoteric group-containing compound, or a nonionic group-containing compound can be used, but the excellent storage stability of the coating agent of the present invention can be used. From the viewpoint of maintaining, it is preferable to use a nonionic group-containing compound.

  The nonionic group-containing compound includes a group having at least one active hydrogen atom in the molecule and consisting of a repeating unit of ethylene oxide, and a group consisting of a repeating unit of ethylene oxide and another repeating unit of alkylene oxide. A compound having at least one functional group selected from the group 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.

  The aqueous urethane resin composition containing the urethane resin (A) and the aqueous medium obtained by the above method can improve the scratch resistance and chemical resistance of the coating film or printed matter to be formed. When the water-based urethane resin composition is used as an ink binder, the ink drying property and the ink ejection stability can be improved. Therefore, it is preferably a printing ink binder, more preferably an ink jet printing ink binder. Can be used for

  The proportion of the urethane resin (A) in the aqueous urethane resin composition is preferably in the range of 1 to 40% by mass from the viewpoints of storage stability and handleability. In particular, when the aqueous urethane resin composition is used as an ink binder, it is more preferably in the range of 15 to 35% by mass from the viewpoints of storage stability, ejection stability, and handleability of the ink.

Next, the ink binder of the present invention will be described.
The water-based urethane resin composition of the present invention can be used as an ink binder corresponding to various printing formats including ink for inkjet printing. Especially, since it is excellent in the storage stability and discharge stability of an ink, it is preferable to use it for the binder of the ink for inkjet printing.

  The ink for inkjet printing of this invention contains a pigment, dye, and other various additives as needed other than the said binder for inkjet printing inks.

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 additives include polymer dispersants, viscosity modifiers, wetting agents, antifoaming agents, surfactants, preservatives, pH adjusting agents, chelating agents, plasticizers, ultraviolet absorbers, and antioxidants. In addition, acrylic resins and the like that have been used as binders for conventional ink jet printing inks can be used.

  As the polymer 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 using the polymer dispersant, an acid or a base may be used in combination to neutralize the polymer dispersant.

  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 binder for inkjet ink, and if necessary, the additive using various dispersing devices.

  (2) An ink precursor comprising 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 ink, and an aqueous medium and an additive, if necessary, using various dispersing devices.

An ink precursor containing a pigment that can be used in the ink production method described in (2) above can be prepared, for example, by the following method.
(I) A pigment obtained by mixing a kneaded product obtained by pre-kneading additives such as a pigment and a polymer dispersing agent 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 containing
(Ii) After the pigment and the polymer dispersant are mixed using various dispersing devices, the polymer dispersant is deposited on the surface of the pigment by controlling the solubility of the polymer dispersant, and further dispersed. A method of preparing an ink precursor comprising an aqueous dispersion containing a pigment by mixing them using an apparatus.
(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

  In addition, the ink for ink jet printing contains 0.1 to 10% by mass of the urethane resin (A) with respect to the whole ink for ink jet printing. It is preferable in order to balance the properties, and it is preferable to contain 50 to 95% by mass of an aqueous medium and 0.5 to 15% by mass of a pigment.

  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.

  The printed matter printed using the ink for ink jet printing of the present invention has excellent scratch resistance, so that it does not easily cause deterioration of a printed image due to lack of pigment or the like and has a high color density image. Therefore, it can be used for various applications such as photo printing by ink jet printing and printed matter obtained by high speed printing by ink jet printing.

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

[Example 1]
In a nitrogen-substituted container equipped with a thermometer, a nitrogen gas introduction tube, and a stirrer, 123.8 parts by mass of a polyether polyol (“PTMG 2000” manufactured by Mitsubishi Chemical Corporation, polytetramethylene glycol, number average molecular weight 2000), 2,1-dimethylolpropionic acid 14.1 parts by mass, Ymer N120 (Perstorp) 16.0 parts by mass and isophorone diisocyanate 40.4 parts by mass in the presence of 64.7 parts by mass of methyl ethyl ketone as the organic solvent. The reaction was continued for an hour, and 39.9 parts by mass of methyl ethyl ketone was added as a diluent solvent, and the reaction was further continued.

  When the weight average molecular weight of the reaction product produced by the reaction reaches a range of 20000 to 50000, the reaction is terminated by adding 1.2 parts by mass of methanol, and 40.8 parts by mass of methyl ethyl ketone as a diluent solvent. By adding, an organic solvent solution of urethane resin was obtained.

  Next, 11.4 parts by mass of 50 mass% aqueous potassium hydroxide solution is added to the organic resin solution of the urethane resin to neutralize part or all of the carboxyl groups of the urethane resin, and further 859.8 parts by mass of water. Was added and stirred sufficiently, and after aging for about 1 hour, the solvent was removed to obtain an aqueous urethane resin composition having a nonvolatile content of 20% by mass.

[Example 2]
In a nitrogen-substituted container equipped with a thermometer, a nitrogen gas introduction tube, and a stirrer, 74.5 parts by mass of a polyether polyol (“PTMG2000”, polytetramethylene glycol manufactured by Mitsubishi Chemical Corporation, number average molecular weight 2000), In the presence of 14.2 parts by mass of 2,2-dimethylolpropionic acid, 61.4 parts by mass of Ymer N120 (Perstorp) and 44.3 parts by mass of isophorone diisocyanate as organic solvents in the presence of 64.7 parts by mass of methyl ethyl ketone. The reaction was continued, 39.9 parts by mass of methyl ethyl ketone was added as a diluent solvent, and the reaction was further continued.

  When the weight average molecular weight of the reaction product generated by the reaction reaches a range of 20000 to 50000, the reaction is terminated by adding 1.3 parts by mass of methanol, and 40.6 parts by mass of methyl ethyl ketone as a diluent solvent. By adding, an organic solvent solution of urethane resin was obtained.

  Next, 11.4 parts by mass of 50 mass% aqueous potassium hydroxide solution is added to the organic resin solution of the urethane resin to neutralize part or all of the carboxyl groups of the urethane resin, and further 859.8 parts by mass of water. Was added and stirred sufficiently, and after aging for about 1 hour, the solvent was removed to obtain an aqueous urethane resin composition having a nonvolatile content of 20% by mass.

[Example 3]
In a nitrogen-substituted container equipped with a thermometer, a nitrogen gas introduction tube, and a stirrer, polyether polyol ("PTMG2000", polytetramethylene glycol manufactured by Mitsubishi Chemical Corporation, number average molecular weight 2000), 112.4 parts by mass, 2,2-dimethylolpropionic acid 14.2 parts by weight, Ymer N120 (Perstorp) 17.7 parts by weight, 1,4-cyclohexanedimethanol 10.6 parts by weight and isophorone diisocyanate 39.6 parts by weight, an organic solvent For 4 hours in the presence of 64.7 parts by weight of methyl ethyl ketone, 39.9 parts by weight of methyl ethyl ketone was added as a diluent, and the reaction was continued.

  When the weight average molecular weight of the reaction product generated by the reaction reached a range of 20000 to 50000, the reaction was terminated by adding 1.6 parts by mass of methanol, and 40.3 parts by mass of methyl ethyl ketone as a diluent solvent. By adding, an organic solvent solution of urethane resin was obtained.

  Next, 11.4 parts by mass of 50 mass% aqueous potassium hydroxide solution is added to the organic resin solution of the urethane resin to neutralize part or all of the carboxyl groups of the urethane resin, and further 859.8 parts by mass of water. Was added and stirred sufficiently, and after aging for about 1 hour, the solvent was removed to obtain an aqueous urethane resin composition having a nonvolatile content of 20% by mass.

[Example 4]
In a nitrogen-substituted container equipped with a thermometer, a nitrogen gas inlet tube, and a stirrer, polyether polyol (“Excenol 2020”, polypropylene glycol manufactured by Asahi Glass Co., Ltd., number average molecular weight 2000), 112.4 parts by mass, 2, Methyl ethyl ketone containing 14.2 parts by mass of 2-dimethylolpropionic acid, 17.7 parts by mass of Ymer N120 (Perstorp), 10.6 parts by mass of 1,4-cyclohexanedimethanol and 39.6 parts by mass of isophorone diisocyanate as organic solvents The reaction was carried out in the presence of 64.7 parts by mass for 4 hours, and 39.9 parts by mass of methyl ethyl ketone was added as a diluent solvent, and the reaction was further continued.

  When the weight average molecular weight of the reaction product generated by the reaction reached a range of 20000 to 50000, the reaction was terminated by adding 1.6 parts by mass of methanol, and 40.3 parts by mass of methyl ethyl ketone as a diluent solvent. By adding, an organic solvent solution of urethane resin was obtained.

  Next, 11.4 parts by mass of 50 mass% aqueous potassium hydroxide solution is added to the organic resin solution of the urethane resin to neutralize part or all of the carboxyl groups of the urethane resin, and further 859.8 parts by mass of water. Was added and stirred sufficiently, and after aging for about 1 hour, the solvent was removed to obtain an aqueous urethane resin composition having a nonvolatile content of 20% by mass.

[Example 5]
In a nitrogen-substituted container equipped with a thermometer, a nitrogen gas introduction tube, and a stirrer, a polycarbonate polyol ("Ethanacol UH-200", a copolymer of diethyl carbonate and 1,6-hexanediol manufactured by Ube Industries, Ltd. Diol, number average molecular weight of about 2000) 112.4 parts by mass, 14.2 parts by mass of 2,2-dimethylolpropionic acid, 17.7 parts by mass of Ymer N120 (Perstorp), 10.4-cyclohexanedimethanol 10.6 Mass parts and 39.6 parts by mass of isophorone diisocyanate were reacted for 4 hours in the presence of 64.7 parts by mass of methyl ethyl ketone as an organic solvent, 39.9 parts by mass of methyl ethyl ketone was added as a diluting solvent, and the reaction was further continued.

  When the weight average molecular weight of the reaction product generated by the reaction reached a range of 20000 to 50000, the reaction was terminated by adding 1.6 parts by mass of methanol, and 40.3 parts by mass of methyl ethyl ketone as a diluent solvent. By adding, an organic solvent solution of urethane resin was obtained.

  Next, 11.4 parts by mass of 50 mass% aqueous potassium hydroxide solution is added to the organic resin solution of the urethane resin to neutralize part or all of the carboxyl groups of the urethane resin, and further 859.8 parts by mass of water. Was added and stirred sufficiently, and after aging for about 1 hour, the solvent was removed to obtain an aqueous urethane resin composition having a nonvolatile content of 20% by mass.

[Example 6]
In a nitrogen-substituted container equipped with a thermometer, a nitrogen gas inlet tube, and a stirrer, 82.6 parts by mass of a polyether polyol (“PTMG 2000”, polytetramethylene glycol manufactured by Mitsubishi Chemical Corporation, number average molecular weight 2000), 2,2-dimethylolpropionic acid 13.9 parts by mass, Ymer N120 (Perstorp) 16.0 parts by mass, 1,4-cyclohexanedimethanol 46.4 parts by mass and isophorone diisocyanate 35.5 parts by mass, an organic solvent For 4 hours in the presence of 64.8 parts by weight of methyl ethyl ketone, 39.9 parts by weight of methyl ethyl ketone was added as a diluting solvent, and the reaction was continued.

  When the weight average molecular weight of the reaction product produced by the reaction reaches a range of 20000 to 50000, the reaction is terminated by adding 3.1 parts by mass of methanol, and further 38.9 parts by mass of methyl ethyl ketone as a diluent solvent. By adding, an organic solvent solution of urethane resin was obtained.

  Next, by adding 11.2 parts by mass of a 50% by mass aqueous potassium hydroxide solution to the organic solvent solution of the urethane resin, part or all of the carboxyl groups of the urethane resin are neutralized, and further 859.9 parts by mass of water. Was added and stirred sufficiently, and after aging for about 1 hour, the solvent was removed to obtain an aqueous urethane resin composition having a nonvolatile content of 20% by mass.

[Comparative Example 1]
In a nitrogen-substituted container equipped with a thermometer, a nitrogen gas introduction tube, and a stirrer, polyether polyol ("PTMG1000", polytetramethylene glycol manufactured by Mitsubishi Chemical Corporation, number average molecular weight 1000) 141.0 parts by mass, 14.2 parts by mass of 2,2-dimethylolpropionic acid and 39.1 parts by mass of isophorone diisocyanate are reacted for 4 hours in the presence of 64.7 parts by mass of methyl ethyl ketone as an organic solvent, and 39.9 parts of methyl ethyl ketone as a diluting solvent. Mass parts were added, and the reaction was further continued.

  When the weight average molecular weight of the reaction product generated by the reaction reaches a range of 20000 to 50000, the reaction is terminated by adding 1.1 parts by mass of methanol, and 40.8 parts by mass of methyl ethyl ketone as a diluent solvent. By adding, an organic solvent solution of urethane resin was obtained.

  Next, 11.4 parts by mass of a 50% by mass aqueous potassium hydroxide solution is added to the organic solvent solution of the urethane resin to neutralize part or all of the carboxyl groups of the urethane resin, and further 859.8 parts by mass of water. Was added and stirred sufficiently, and after aging for about 1 hour, the solvent was removed to obtain an aqueous urethane resin composition having a nonvolatile content of 20% by mass.

[Comparative Example 2]
In a nitrogen-substituted container equipped with a thermometer, a nitrogen gas introduction tube, and a stirrer, 81.5 parts by mass of a polyether polyol (“PTMG 2000” manufactured by Mitsubishi Chemical Corporation, polytetramethylene glycol, number average molecular weight 2000), 49.3 parts by weight of Ymer N120 (Perstorp) and 19.1 parts by weight of isophorone diisocyanate were reacted for 4 hours in the presence of 50.0 parts by weight of methyl ethyl ketone as an organic solvent, and 30.8 parts by weight of methyl ethyl ketone was added as a diluting solvent. The reaction was continued further.

  When the weight average molecular weight of the reaction product generated by the reaction reaches a range of 20000 to 50000, the reaction is terminated by adding 0.6 parts by mass of methanol, and further 31.8 parts by mass of methyl ethyl ketone as a diluent solvent. By adding, an organic solvent solution of urethane resin was obtained.

  Next, 645.9 parts by mass of water was added and sufficiently stirred, and after aging for about 1 hour, the solvent was removed to obtain an aqueous urethane resin composition having a nonvolatile content of 15% by mass.

[Method for measuring weight average molecular weight]
The weight average molecular weight of the urethane resin (A) was measured by gel permeation chromatograph (GPC method). Specifically, the urethane resin (A) 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 a RI detector with a flow rate of 1 mL / min, a sample injection amount of 500 μL, and a sample concentration of 0.4%.

Preparation Example 1 (Aqueous dispersion of quinacridone pigment)
1500 g of vinyl polymer (styrene / acrylic acid / methacrylic acid = 77/10/13 (mass ratio), weight average molecular weight, acid value 156 mgKOH / g), quinacridone pigment (chromoftal jet magenta DMQ, 4630 g of 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 688 g of 34% by weight potassium hydroxide aqueous solution Is loaded into a planetary mixer PLM-V-50V (manufactured by Inoue Seisakusho Co., Ltd.) with a capacity of 50 L, the jacket is heated, and the speed is low until the temperature of the contents reaches 60 ° C. (rotation speed: 21 rev / min, revolution) Kneading at a rotation speed of 14 revolutions / minute) After the temperature reached 60 ° C., a high speed (rotation number of revolutions: 35 revolutions / min, the revolution speed: 24 revolutions / min) Switch to, 4 hours and continued kneading.

  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 to prepare a precursor of an aqueous pigment dispersion (aqueous pigment dispersion before dispersion treatment). Liquid).

  Next, 18 kg of this aqueous pigment 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., After processing using a rotation speed: 2660 rotations / minute (disk peripheral speed: 12.5 m / sec), liquid feeding amount: 200 g / 10 seconds), the solution passing through the bead mill was centrifuged at 13000 G × 10 minutes, An aqueous pigment dispersion of a quinacridone pigment was obtained by performing a filtration treatment with a filter having an effective pore size of 0.5 μm. The concentration of the quinacridone pigment in this aqueous pigment dispersion was 14.9% by mass.

[Example of ink-jet printing ink preparation]
The aqueous urethane obtained in Examples 1 to 6 and Comparative Examples 1 and 2 so that the concentration of the quinacridone pigment is 4% by mass and the concentration of the urethane resin is 1% by mass with respect to the total amount of the ink for inkjet printing. A resin composition, a quinacridone pigment obtained in Preparation Example 1, 2-pyrrolidinone, triethylene glycol monobutyl ether, glycerin, a surfactant (Surfinol 440, manufactured by Air Products) and ion-exchanged water Ink for inkjet printing was prepared by mixing and stirring according to the following blending ratio.

(Inkjet pigment ink mix ratio)
-Quinacridone pigment aqueous dispersion obtained in Preparation Example 1 (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
-Aqueous urethane resin composition obtained in Examples 1-6 or Comparative Examples 1-2; 5.0 g

[Evaluation of storage stability of ink]
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)] × 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)] × 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 on the Photomart D5360 (manufactured by Hewlett-Packard Company) in which a black ink cartridge was filled with the ink for inkjet printing, and the state of the nozzle was confirmed. 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 nozzles before and after continuous solid printing was evaluated as the ink ejection stability. The evaluation criteria are described below.

[Criteria]
○: No change in nozzle state and no discharge abnormality occurred Δ: Slight ink adhesion to the nozzle was confirmed, but no abnormality in the ink discharge direction occurred ×: Ink Non-ejection occurrence

[Evaluation of chemical resistance (alkali 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 ink for inkjet printing is black ink. An evaluation printed matter was obtained by filling the cartridge and performing solid printing with a print density setting of 100%.

  After the printed matter for evaluation is dried at room temperature for 10 minutes, a 0.5% by mass aqueous potassium hydroxide solution is sprayed once onto the printed surface using a general spray, and the printed surface is rubbed with a finger after 10 seconds. Then, the surface state of the printed surface was visually evaluated. The evaluation criteria are described below.

[Criteria]
A: There was no peeling on the printed surface, and no decolorization was observed.
B: Although there was no peeling at all on the printed surface, a slight amount of decoloration was observed at a level causing no practical problem.
C: Some peeling occurred on the printed surface, and some decolorization was observed.
D: Significant peeling occurred on the printed surface, and decolorization was also observed.

[Evaluation of scratch 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 ink for inkjet printing is black ink. An evaluation printed matter was obtained by filling the cartridge and performing solid printing with a print density setting of 100%.

  After the printed matter was dried at room temperature for 3 minutes, the printed surface was rubbed with a nail and the rubbing condition such as the color of the printed surface was visually evaluated. The evaluation criteria are described below.

[Criteria]
A: There was no scratch on the printed surface, and no peeling of the coloring material was observed.
B: Although a slight scratch of a level that causes no practical problem occurred on the printed surface, peeling of the coloring material was not observed.
C: Although the printed surface was scratched, no peeling of the coloring material was observed.
D: Significant scratches were generated on the printing surface and peeling of the coloring material was observed.

[Evaluation of ink drying properties]
A diagnostic page was printed with Photomart D5360 (manufactured by Hewlett Packard) in which the ink for inkjet printing was filled in a black ink cartridge on the surface of art paper (manufactured by Oji Paper Co., Ltd., OK Topcoat +).

The amount of ink adhering to the PPC paper when the general PPC paper (plain paper for multifunction peripherals) is overlapped on the printing surface after 20 seconds from the end of printing and pressed with a finger to peel off the PPC paper. Was used to evaluate the drying properties of the ink.
A: 0% ink adhesion to the contact area on the printing surface
B: The ink adhesion amount exceeds 0% and 3% or less with respect to the contact area on the printing surface. C: The ink adhesion amount exceeds 3% and 5% or less with respect to the printing surface contact area. D: The ink adhesion amount exceeds 5% and less than 10% with respect to the contact area on the printing surface. E: The ink adhesion amount exceeds 10% with respect to the contact area with the printing surface.

[Evaluation of gloss]
Using a commercially available thermal jet type inkjet printer (Photomart D5360; manufactured by Hewlett Packard) on the printing surface of photographic paper (glossy) [HP Advanced Photo Paper manufactured by Hewlett Packard], which is a dedicated paper for inkjet printing, the inkjet printing described above. The black ink cartridge was filled with the ink for printing, and solid printing with a printing density setting of 100% was performed.

  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 Microhaze Plus (manufactured by Toyo Seiki Seisakusho Co., Ltd.), and the average value Was calculated.

Abbreviations in Tables 1 and 2 are described below.
“DMPA”; 2,2-dimethylolpropionic acid “YmerN120”; polyol having a polyethylene oxide chain in the side chain manufactured by Perstorp (molecular weight 800)
“CHDM”; 1,4-cyclohexanedimethanol “PTMG”; polytetramethylene glycol manufactured by Mitsubishi Chemical Corporation, number average molecular weight 2000
“PPG”; “Exenol 2020” polypropylene glycol manufactured by Asahi Glass Co., Ltd., number average molecular weight 2000
“PC”; “Ethanacol UH-200”, a copolymer carbonate diol of diethyl carbonate and 1,6-hexanediol manufactured by Ube Industries, Ltd., number average molecular weight of about 2000
"IPDI"; isophorone diisocyanate

Claims (11)

An aqueous urethane resin composition comprising a urethane resin (A) having an anionic group (a1) and a polyalkylene oxide chain (a2) in the side chain and an aqueous medium. The aqueous urethane resin composition according to claim 1, wherein the urethane resin (A) has 1 to 60% by mass of the polyalkylene oxide chain (a2) based on the total amount of the urethane resin (A). The aqueous urethane resin composition according to claim 1, wherein the polyalkylene oxide chain (a2) is a polyethylene oxide chain. The urethane resin (A) is obtained by reacting a polyol (B) containing an anionic group-containing polyol (b1) and a polyol (b2) having a polyalkylene oxide chain in the side chain, and a polyisocyanate (C). The water-based urethane resin composition of Claim 1 which is what is obtained. The water-based urethane resin composition of Claim 1 whose mass ratio [(a1) / (a2)] of the said anionic group (a1) and the said polyalkylene oxide chain (a2) is 0.06-30. The aqueous urethane resin composition according to claim 4, wherein the polyol (B) further contains an aliphatic cyclic structure-containing polyol (b3). An ink binder comprising the aqueous urethane resin composition according to claim 1. A binder for inkjet printing ink comprising the aqueous urethane resin composition according to any one of claims 1 to 6. The ink for inkjet printing containing the binder for inkjet printing inks of Claim 8, and a pigment or dye. The ink for ink-jet printing according to claim 9, wherein the ink for ink-jet printing contains 0.1 to 10% by mass of the urethane resin (A) with respect to the total amount of the ink for ink-jet printing. A printed matter printed with the ink jet printing ink according to claim 9.