JP5029931B2 - Ink-jet printing ink manufacturing method and printed matter - Google Patents

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.

  As described above, the ink for ink jet printing that can form a printed image that has both excellent scratch resistance and excellent alkali resistance without impairing the good ejection stability and storage stability of the ink is industrially However, an ink for ink jet printing provided with the ink jet ink and a binder for ink jet printing ink that can be used for producing the ink have not yet been found.

JP 2000-1639 A

  The problem to be solved by the present invention is that a printed image having excellent durability such as scratch resistance and alkali resistance can be formed without impairing the good ejection stability and storage stability of the ink. To provide a binder for inkjet printing ink and an inkjet printing ink containing the binder.

  While the inventors have studied to solve the above problem, the improvement in the scratch resistance may be realized by using a resin having a higher molecular weight than the conventional one as a binder for ink jet printing ink. Thought.

  However, when a high molecular weight resin is used as the binder, the resin absorbs an aqueous medium and swells, thereby significantly reducing the ejection stability and storage stability of the ink, and clogging of the ink ejection nozzle and the ink ejection direction. In some cases, the occurrence of abnormalities and the generation of aggregates may occur.

  On the other hand, the improvement in ejection stability and storage stability could be realized by using a relatively low molecular weight binder, but in such a case, the scratch resistance, alkali resistance, and the like are reduced. There was a case.

  Thus, while it is difficult to achieve both the ejection stability and storage stability of the ink and the scratch resistance and alkali resistance, the present inventors have increased the molecular weight by crosslinking in the particles as the binder. Investigation was proceeded with the idea that the above problems could be solved by using the resin particles.

As a result, ink ejection stability is improved when a binder for inkjet printing ink in which composite resin particles that have undergone intra-particle crosslinking are dispersed in an aqueous medium by reacting a polyether polyurethane with an epoxy compound is used. It was also found that the scratch resistance and alkali resistance can be improved without impairing the storage stability.

That is, the present invention provides an inkjet printing ink binder, a pigment or dye, a styrene - an ink jet printing ink containing an acrylic resin, the ink-jet printing ink binders include polyether-based polyurethane (a1) And composite resin particles (A) formed by the reaction of an epoxy compound (a2) containing an aliphatic polyglycidyl ether or a bisphenol glycidyl ether with an aqueous medium (B). The present invention relates to ink for printing and printed matter.
The present invention also provides an ink precursor containing a pigment or dye and a styrene-acrylic resin, and an epoxy compound (a2) containing a polyether polyurethane (a1) and an aliphatic polyglycidyl ether or bisphenol glycidyl ether. And a composite resin particle (A) formed by reaction with an aqueous medium (B) is mixed with a binder for an ink for ink-jet printing.

  The ink for ink jet printing containing the ink jet printing ink binder of the present invention can remove the pigment even when a strong external force is applied without impairing the good ejection stability or storage stability of the ink. It is possible to maintain a high-definition printed image without causing it, and can provide scratch resistance comparable to silver salt photographs and excellent alkali resistance. For example, by photo printing by inkjet printing or high-speed printing by inkjet printing The obtained printed matter can be used in various scenes including outdoor advertising.

  The present invention provides a binder for ink jet printing ink, wherein the composite resin particles (A) formed by reacting polyurethane (a1) and epoxy compound (a2) are dispersed in an aqueous medium (B). is there.

  The composite resin particle (A) used in the present invention is formed by a cross-linking reaction between the polyurethane (a1) and the epoxy compound (a2).

  Specifically, the crosslinking reaction between the polyurethane (a1) and the epoxy compound (a2) is performed between the functional group [X] of the polyurethane (a1) and the epoxy group [Y] of the epoxy compound (a2). It is a reaction.

  The functional group [X] of the polyurethane (a1) may be any functional group that can react with the epoxy group [Y], and examples thereof include a carboxyl group, a carboxylate group, and an amino group. . Among these, a carboxyl group or a carboxylate group is preferable for obtaining a printed material excellent in durability such as alkali resistance.

  As the composite resin particles (A), it is preferable to use composite resin particles that are cross-linked with high density inside the particles from the viewpoint of imparting even better scratch resistance and the like. If the composite resin particles, since a crosslinked structure is formed in the particles, the particles are less likely to swell due to an aqueous medium or the like, and as a result, excellent scratch resistance without impairing ink ejection stability. It is possible to impart sex and the like.

  The degree of crosslinking in the composite resin particles (A) can be evaluated by the gel fraction of the composite resin particles (A), and it is more preferable to use those having a gel fraction of 70% by mass or more. It is preferable for imparting more excellent scratch resistance, and more preferably 85% by mass to 100% by mass.

  Here, when the film formed using the composite resin particles (A) is immersed in methyl ethyl ketone at 25 ° C. for 24 hours, the gel fraction is based on the mass of the film before the immersion. It can be shown by the ratio of the mass of the residue of the film that remains without being eluted in methyl ethyl ketone.

  Specifically, a film having a length of 3 cm, a width of 3 cm, and a thickness of 150 μm is prepared using the composite resin particles (A), and the mass (M) thereof is measured. Next, after immersing the film in methyl ethyl ketone adjusted to 25 ° C. for 24 hours, the residue of the film that did not dissolve in methyl ethyl ketone was separated by filtration through a 300 mesh wire mesh, and the residue was dried at 108 ° C. for 1 hour. Measure the mass (N) of the product. Next, the gel fraction can be calculated by using the values of the masses (M) and (N) and calculating based on the formula [(N) / (M)] × 100.

  As said composite resin particle (A), it is preferable to use what has a hydrophilic group as mentioned above from a viewpoint disperse | distributed stably in an aqueous medium (B).

  As the hydrophilic group, an anionic group, a cationic group, and a nonionic group can be used, and it is more 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 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.

  The hydrophilic group is preferably present in the range of 1 mmol / kg to 2000 mmol / kg, and preferably in the range of 15 mmol / kg to 1500 mmol / kg with respect to the entire composite resin particle (A). It is more preferable when obtaining a binder for ink jet printing ink having good properties and ejection stability.

  The composite resin particles (A) preferably have an average particle diameter in the range of 10 nm to 1000 nm from the viewpoint of maintaining good storage stability and ejection stability. More preferably, it has a particle size. The average particle diameter refers to an average particle diameter on a volume basis measured by a dynamic light scattering method, as will be described later in Examples.

  Moreover, as said composite resin particle (A), it is preferable to use what has an acid value of 1 mgKOH / g-50 mgKOH / g from a viewpoint of hold | maintaining favorable storage stability and discharge stability. In particular, it is more preferable to use one having an acid value of 1 mgKOH / g to 35 mgKOH / g from the viewpoint of maintaining good storage stability and ejection stability and improving alkali resistance. In addition, it is preferable that the said acid value originates in the acid group which a polyurethane (a1) has.

  As the method for producing the composite resin particles (A), a step (I) of producing a polyurethane (a1) by reacting a polyol, a polyisocyanate and, if necessary, a chain extender, and the polyurethane ( A method including the step (II) of producing a composite resin particle (A) by reacting a1) with the epoxy compound (a2) may be mentioned.

  First, the polyurethane (a1) obtained in the step (I) and the step (I) will be described.

  Examples of the polyurethane (a1) include a reaction with the epoxy group [Y] of the epoxy compound (a2) among polyurethanes obtained by reacting the polyol, polyisocyanate, and a chain extender, if necessary. What has functional group [X] provided with property can be used.

As the functional group [X], as described above, for example, a carboxyl group, a carboxylate group, an amino group, and the like can be used.
As a method for producing the polyurethane (a1) having the functional group [X], specifically, a polyol (a1-1) or polyisocyanate (a1-2) having no functional group [X], a functional group A method of producing the polyurethane (a1) by reacting the group [X] -containing compound with a chain extender as necessary may be mentioned.

Examples of the functional group [X] -containing compound used when introducing the functional group [X] into the polyurethane (a1) include a polyol having the functional group [X] and a polyisocyanate having the functional group [X]. Can be used. In addition, when using the polyol which has the said functional group [X], and the polyisocyanate which has functional group [X], the polyol (a1-1) and polyisocyanate (a1-2) which do not have a functional group [X]. ) Is not necessarily used. However, a polyol having a functional group [X] or a polyisocyanate having a functional group [X] is used from the viewpoint of imparting various properties such as good storage stability in an aqueous medium and excellent scratch resistance of a printed image. Even if it is a case where it does, it is preferable to use combining other polyol (a1-1) and polyisocyanate (a1-2).
Examples of the method for producing the polyurethane (a1) using the polyol having the functional group [X] and the polyisocyanate having the functional group [X] include, for example, the polyol having the functional group [X] and the functional group [X ], The polyol (a1-1) which does not have functional group [X], polyisocyanate (a1-2), and the method of making a chain extender react suitably as needed. Thereby, the polyurethane (a1) in which the functional group [X] is introduced into the molecular side chain or molecular end can be obtained.

  Examples of the polyol having the functional group [X] include 2,2′-dimethylolpropionic acid, 2,2′-dimethylolbutanoic acid, 2,2′-dimethylolbutyric acid, and 2,2′-dimethylolvaleric acid. Can be used. Among these, 2,2'-dimethylolpropionic acid is preferably used for obtaining composite resin particles (A) having excellent dispersion stability.

  The polyol having the functional group [X] is a total mass of raw materials that can be used for the production of the polyurethane (a1), specifically, the polyol (a1-1), the polyisocyanate (a1-2), and the functional group. When the group [X] -containing compound and the chain extender are used, it is preferably used in the range of 0.5% by mass to 35% by mass with respect to the total mass including the chain extender.

  Moreover, a polyamine etc. can be used as said functional group [X] containing compound. Specifically, a urethane prepolymer having an isocyanate group or a hydroxyl group at the molecular end is produced by reacting the polyol (a1-1) or polyisocyanate (a1-2), and then the molecular end of the urethane prepolymer. The functional group [X] can be introduced into the molecular terminal of the polyurethane (a1) by reacting the isocyanate group or hydroxyl group present in the compound with a compound having the functional group [X] such as the polyamine.

  Examples of the polyamine usable as the functional group [X] -containing compound include ethylenediamine, 1,2-propanediamine, 1,6-hexamethylenediamine, piperazine, 2,5-dimethylpiperazine, isophoronediamine, 4,4. Diamines such as' -dicyclohexylmethanediamine, 3,3'-dimethyl-4,4'-dicyclohexylmethanediamine, 1,4-cyclohexanediamine; N-hydroxymethylaminoethylamine, N-hydroxyethylaminoethylamine, N-hydroxy Propylaminopropylamine, N-ethylaminoethylamine, N-methylaminopropylamine; diethylenetriamine, dipropylenetriamine, triethylenetetramine; hydrazine, N, N′-dimethylhydrazine, 1,6-hex Methylenebishydrazine; succinic acid dihydrazide, adipic acid dihydrazide, glutaric acid dihydrazide, sebacic acid dihydrazide, isophthalic acid dihydrazide; β-semicarbazide propionic acid hydrazide, 3-semicarbazide-propyl-carbazic acid ester, semicarbazide-3-semicarbazide Methyl-3,5,5-trimethylcyclohexane and the like can be used.

  When the functional group [X] is an acid group such as a carboxyl group or a carboxylate group, the acid group is present in a range where the acid value of the polyurethane (a1) is 1 mgKOH / g to 70 mgKOH / g. preferable.

  As said polyol (a1-1) which can be used for manufacture of the said polyurethane (a1), various polyols other than the polyol which has the said functional group [X] can be used.

  Moreover, it is preferable to use what has a hydrophilic group as said polyurethane (a1) from a viewpoint of providing the favorable storage stability etc. in the aqueous medium (B) of the said composite resin particle (A).

  The hydrophilic group can be introduced into the polyurethane (a1) by using a hydrophilic group-containing polyol as the polyol (a1-1).

  As the hydrophilic group-containing polyol, for example, an anionic group-containing polyol, a cationic group-containing polyol, a nonionic group-containing polyol, and the like can be used, and it is particularly preferable to use an anionic group-containing polyol. It is preferable for maintaining the storage stability.

  As said anionic group containing polyol, anionic group containing polyols, such as a carboxyl group containing polyol and a sulfonic acid group containing polyol, can be used, for example.

Examples of the carboxyl group-containing polyol 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, a carboxyl group-containing polyester polyol obtained by reacting the carboxyl group-containing polyol with various polycarboxylic acids or lactones, a vinyl polymer having two or more hydroxyl groups at one end, and the like can also be used.
Specifically, the vinyl polymer having two or more hydroxyl groups at one end is a vinyl monomer containing a carboxyl group in the presence of thioglycerin such as 3-mercapto-1,2-propanediol. Those obtained by polymerization can be suitably used.

  Examples of the sulfonic acid group-containing polyol 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. Polyester polyol obtained by reacting can be used.

  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 when neutralizing the anionic group include ammonia, triethylamine, morpholine, organic amines such as monoethanolamine and diethylethanolamine having a boiling point of 100 ° C. or higher, NaOH, KOH, LiOH A metal hydroxide containing etc. can be used. The basic compound is preferably used in the range of basic compound / anionic group = 0.2 to 3.0 (molar ratio) from the viewpoint of improving the dispersion stability of the ink obtained. It is more preferable to use in the range of 6 to 1.5 (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.

  The cationic group is partially or entirely neutralized with an acidic compound such as formic acid, acetic acid, phosphoric acid, propionic acid, succinic acid, glutaric acid, tartaric acid, adipic acid, or dimethyl sulfate, diethyl sulfate, methyl It may be quaternized with a quaternizing agent such as chloride or ethyl chloride.

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

  The hydrophilic group-containing polyol includes the polyol (a1-1), the polyisocyanate (a1-2), the functional group [X] -containing compound, and the chain extender, which are raw materials that can be used for the production of the polyurethane (a1). When is used, it is preferably used in the range of 1% by mass to 45% by mass with respect to their total mass.

  In addition, examples of the polyol having the functional group [X] as the functional group [X] -containing compound and the hydrophilic group-containing polyol partially overlap. For example, 2,2-dimethylolpropionic acid can introduce a carboxyl group as a hydrophilic group into the polyurethane (a1), while introducing a carboxyl group as the functional group [Y] into the polyurethane (a1). .

  The carboxyl group introduced into the polyurethane (a1) for the purpose of increasing the crosslinking density in the particles by reacting with the epoxy group [Y] of the epoxy compound (a2) acts as the functional group [X]. In addition, since it does not act as a hydrophilic group after the reaction, a polyol such as 2,2-dimethylolpropionic acid used for introducing a carboxyl group into the polyurethane (a1) for the purpose is the functional group described above. The polyol having the group [X] is exemplified.

  On the other hand, in order to improve the water dispersion stability of the composite resin particle (A), it is a carboxyl group introduced as an anionic group, and does not react with the epoxy group [Y], so that the composite resin particle (A) The carboxyl group remaining in the solvent and the carboxylate group formed by further neutralization act as a hydrophilic group, and therefore, used for introducing a carboxyl group into the polyurethane (a1) for this purpose. An anionic group-containing polyol such as 2-dimethylolpropionic acid was exemplified as the hydrophilic group-containing polyol. The cationic group-containing polyol that can be used for the hydrophilic group-containing polyol is the same as the anionic group-containing polyol.

  As a polyol (a1-1) used for manufacture of the said polyurethane (a1), in addition to the said hydrophilic group containing polyol, another polyol can be used in combination as needed.

  As said other polyol, polyether polyol, polyester polyol, polycarbonate polyol etc. other than the polyol which has the said functional group [X], and the said hydrophilic group containing polyol can be used, for example. Among these, as the other polyol, the use of the polyether polyol imparts excellent scratch resistance and alkali resistance without impairing excellent ink storage stability and ink ejection properties. Is preferable.

  Examples of the polyether polyol that can be used as the other polyol include those obtained by addition polymerization of alkylene oxide using one or more compounds having two or more active hydrogen atoms as an initiator. .

  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.

  As the polyether polyol, it is preferable to use polyoxytetramethylene glycol or polyoxypropylene glycol from the viewpoint of obtaining a binder for ink jet printing ink capable of imparting excellent ejection stability of the ink.

  As the polyether polyol that can be used for the other polyol, it is preferable to use a polyether polyol having a number average molecular weight of 600 to 5,000, and more preferably 800 to 3,000.

  The polyether polyol, preferably the polyether polyol having a number average molecular weight of 600 to 5,000, is a raw material that can be used for the production of the polyurethane (a1). The polyol (a1-1) and the polyisocyanate (a1-2) When the functional group [X] -containing compound and the chain extender are used, it is preferably in the range of 15% by mass to 80% by mass with respect to their total mass.

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

  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, hydroquinone, resorcin, bisphenol-A, bisphenol-F, 4 , 4'-biphenol and other relatively low And molecular weight of the dihydroxy compound, polyethylene glycol, polypropylene glycol, and polyether polyols such as polyoxytetramethylene glycol, polyhexamethylene adipate, polyhexamethylene succinate, may be used polyester polyols such as polycaprolactone and the like.

  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 include succinic acid, adipic acid, sebacic acid, dodecanedicarboxylic acid, terephthalic acid, isophthalic acid, phthalic acid, and anhydrides or ester-forming derivatives thereof.

  In addition to the above-mentioned other polyols, it is preferable to use an aliphatic cyclic structure-containing polyol in order to improve the scratch resistance of the printed matter.

  Examples of the aliphatic cyclic structure-containing polyol include cyclobutanediol, cyclopentanediol, 1,4-cyclohexanediol, cycloheptanediol, cyclooctanediol, cyclohexanedimethanol, hydroxypropylcyclohexanol, and tricyclo [5,2,1. , 0,2,6] decane-dimethanol, bicyclo [4,3,0] -nonanediol, dicyclohexanediol, tricyclo [5,3,1,1] dodecanediol, bicyclo [4,3,0] no Nandimethanol, tricyclo [5,3,1,1] dodecane-diethanol, hydroxypropyltricyclo [5,3,1,1] dodecanol, spiro [3,4] octanediol, butylcyclohexanediol, 1,1'- Bicyclohexylidenediol Cyclohexanetriol, hydrogenated bisphenol - Le A, such as 1,3-adamantane-diol, generally can be used 100 to 500 as low molecular weight aliphatic cyclic structure-containing polyol. The molecular weight of the aliphatic cyclic structure-containing polyol is based on the formula weight.

  The aliphatic cyclic structure-containing polyol having a molecular weight of 100 to 500 is the polyol (a1-1), the polyisocyanate (a1-2), and the functional group, which are raw materials that can be used for the production of the polyurethane (a1). When the group [X] -containing compound and the chain extender are used, the content is preferably in the range of 0.5 to 35% by mass with respect to the total mass thereof.

  In addition to the above-mentioned other polyols, for example, 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-heptanediol and the like can be used.

  Moreover, what does not have functional group [X] can be used as polyisocyanate (a1-2) which can be used for manufacture of the said polyurethane (a1), for example, 4,4'- diphenylmethane diisocyanate, 2 , 4'-diphenylmethane diisocyanate, carbodiimide modified diphenylmethane diisocyanate, crude diphenylmethane diisocyanate, phenylene diisocyanate, tolylene diisocyanate, naphthalene diisocyanate, and other aromatic polyisocyanates, hexamethylene diisocyanate, lysine diisocyanate, cyclohexane diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, Such as xylylene diisocyanate and tetramethyl xylylene diisocyanate It can be used polyisocyanates having aliphatic polyisocyanate or an alicyclic structure. Among them, it is preferable to use an aliphatic polyisocyanate from the viewpoint of preventing yellow discoloration, and from the viewpoint of further improving the scratch resistance and alkali resistance in addition to the above-mentioned discoloration prevention, an aliphatic cyclic structure-containing polyisocyanate. Is preferably used.

  The polyurethane (a1) can be produced, for example, by mixing and reacting a polyol and polyisocyanate in the absence of a solvent or in the presence of an organic solvent. Specifically, the polyurethane (a1) includes the polyol (a1-1), the polyisocyanate (a1-2), and functional groups such as the functional group [X] -containing polyol and the functional group [X] -containing polyisocyanate. It can be produced by mixing and reacting with a group [X] -containing compound. When the organic solvent is used, the organic solvent is preferably removed by a method such as distillation when the polyurethane (a1) is made aqueous.

  Also, a urethane prepolymer having a hydroxyl group or an isocyanate group at the molecular end is produced by reacting the polyol (a1-1) and the polyisocyanate (a1-2) in advance in the absence of a solvent or in the presence of an organic solvent. Then, the urethane prepolymer and the functional group [X] -containing compound such as the polyamine are mixed and reacted to produce the polyurethane (a1) having the functional group [X] at the molecular terminal. Also in this case, when the organic solvent is used, the organic solvent is preferably removed by a method such as distillation when the polyurethane (a1) is made aqueous.

  For example, the reaction of the polyol and polyisocyanate used for the production of the polyurethane (a1) is such that the equivalent ratio of the isocyanate group of the polyisocyanate to the hydroxyl group of the polyol is in the range of 0.8 to 2.5. It is preferable to perform, and it is more preferable to carry out in the range of 0.9-1.5. The polyol and polyisocyanate include the polyol (a1-1) and polyisocyanate (a1-2), the functional group [X] -containing polyol, the functional group [X] -containing polyisocyanate, and the like.

  Examples of the organic solvent that can be used in producing the polyurethane (a1) 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 producing the polyurethane (a1), the chain extender can be used as necessary for the purpose of increasing the molecular weight from the viewpoint of improving the scratch resistance.
When the chain extender is used, for example, the polyol (a1-1), the polyisocyanate (a1-2), and the functional group [X] -containing compound are reacted in the absence of a solvent or in the presence of an organic solvent. The polyurethane (a1) can be produced by reacting the polyurethane with a chain extender. When the organic solvent is used, the organic solvent is preferably removed by a method such as distillation when the polyurethane (a1) is made aqueous.

  As a chain extender that can be used when the polyurethane (a1) is produced, 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, 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.

  The chain extender is used, for example, in such a range that the equivalent of the amino group and active hydrogen atom-containing group of the chain extender is 1.9 or less (equivalent ratio) with respect to the equivalent of the isocyanate group of the polyurethane. It is preferable to use within a range of 0.3 to 1.0 (equivalent ratio).

  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 (a1) 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 polyurethane (a1) obtained by the above method, in order to obtain sufficient alkali resistance, scratch resistance and alcohol resistance, it is preferable to use a polyurethane having a weight average molecular weight in the range of 10,000 to 200,000. It is more preferable to use the thing of the range of 20000-80000.

  Moreover, the dispersion | distribution in the aqueous medium (B) of the polyurethane (a1) manufactured by the said method can be performed by the following methods, when the said polyurethane (a1) is a hydrophilic group containing polyurethane, for example.

  [Method 1] After neutralizing or quaternizing some or all of the hydrophilic groups of the polyurethane (a1) produced by the above method, the aqueous medium (B) is added and dispersed in water. Accordingly, a method of producing an aqueous dispersion of polyurethane (a1) by supplying and reacting the chain extender accordingly.

[Method 2] Polyurethane obtained by reacting polyol (a1-1) and polyisocyanate (a1-2) and, if necessary, the chain extender are charged into a reaction vessel in a batch or divided. The polyurethane (a1) is produced by chain extension reaction, and then the hydrophilic group which the obtained polyurethane (a1) may have is neutralized or quaternized, and then an aqueous medium. A method for producing an aqueous dispersion of polyurethane (a1) by adding (B) and dispersing in water.
When an organic solvent is used in the production of the polyurethane (a1), an aqueous dispersion of the polyurethane (a1) is produced by the methods 1 and 2, and then the organic solvent is distilled as necessary. It is preferable to remove by.

  Moreover, when using what does not have a hydrophilic group as said polyurethane (a1), when dispersing the said polyurethane (a1) in an aqueous medium (B), the following emulsifier etc. can be used. . In addition, also when using hydrophilic group containing polyurethane as said polyurethane (a1), in said [Method 1]-[Method 2], you may use an emulsifier as needed. 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, 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 (a1).

  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 ink of the present invention is maintained. Therefore, 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.

  Next, the process (II) for producing the composite resin particles (A) by reacting the polyurethane (a1) obtained above and the epoxy compound (a2) will be described.

  The reaction between the polyurethane (a1) and the epoxy compound (a2) is a reaction between the functional group [X] of the polyurethane (a1) and the epoxy group [Y] of the epoxy compound (a2). .

  As said epoxy compound (a2), epoxy resins, such as a novolak type, a cresol type, a phenol type, a bisphenol A type, a bisphenol F type, can be used, for example.

  Specifically, aliphatic polyglycidyl ether or bisphenol diglycidyl ether can be used as the epoxy compound (a2) because it can impart excellent scratch resistance without impairing the ejection stability of the ink. preferable.

  Examples of the aliphatic polyglycidyl ether include cyclohexanedimethanol diglycidyl ether, cyclohexanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, sorbitol polyglycidyl ether, polyglycerol polyglycidyl ether, pentaerythritol polyglycidyl ether, Diglycerol polyglycidyl ether, glycerol polyglycidyl ether, trimethylolpropane polyglycidyl ether, polypropylene glycol diglycidyl ether, and the like can be used.

  Examples of the bisphenol diglycidyl ether include bisphenol A type diglycidyl ether, bisphenol F type diglycidyl ether, and bisphenol S type diglycidyl ether.

  Moreover, as said epoxy compound (a2), it is preferable to use what has an epoxy equivalent of 100-2000 from a viewpoint of forming a sufficient crosslinking point when providing the outstanding abrasion resistance. Furthermore, it is more preferable to use what has an epoxy equivalent of 100-500 when providing the outstanding abrasion resistance.

  The reaction between the functional group [X] and the epoxy group [Y] can be performed, for example, by mixing the polyurethane (a1) obtained in the step (I) and the epoxy compound (a2). Specifically, a method in which the organic solvent solution or aqueous dispersion of the polyurethane (a1) obtained in the step (I) and the epoxy compound (a2) are mixed can be mentioned. The mixing may be performed before or after neutralizing the hydrophilic group of the polyurethane (a1), or may be performed at any time before or after the organic solvent is removed.

  Although reaction with the said functional group [X] and the said epoxy group [Y] changes with kinds etc. of the epoxy compound (a2) to be used, Preferably it is 50 to 150 degreeC, More preferably, it is the range of 65 to 100 degreeC. Therefore, it is preferable to carry out stirring for about 1 to 10 hours.

  The polyurethane (a1) and the epoxy compound (a2) have a molar ratio of the functional group [X] of the polyurethane (a1) and the epoxy group [Y] of the epoxy compound (a2) [epoxy group [Y ] / Functional group [X]] is preferably mixed and reacted in the range of 1/20 to 1/1, and mixed and reacted in the range of 1/5 to 4/5. In addition, it is more preferable to obtain an excellent scratch-resistant printed matter by increasing the crosslinking density inside the composite resin particles (A) without impairing the storage stability.

  Here, when the functional group [X] is capable of acting as a hydrophilic group such as the carboxyl group or amino group, the viewpoint of maintaining excellent storage stability of the resulting composite resin particle (A) Therefore, the molar ratio [epoxy group [Y] / functional group [X]] is preferably mixed and reacted in the range of 1/20 to 9/10, and mixed in the range of 1/5 to 4/5. It is more preferable to react. Thereby, in the said composite resin particle (A), an epoxy group [Y] and unreacted functional group [X] can be made to remain as a hydrophilic group, and the said composite resin particle (B) in an aqueous medium (B) ( The storage stability of A) can be improved.

  The aqueous medium (B) used in the ink jet printing ink binder of the present invention is one in which the composite resin particles (A) are dispersed.

  Examples of the aqueous medium (B) include water, organic solvents miscible with water, and mixtures 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.

  In the present invention, when an aqueous dispersion containing the polyurethane (a1) and the aqueous medium (B) is produced when producing the polyurethane (a1), the aqueous medium (B) is continuously used. be able to.

  The aqueous medium (B) is preferably contained in an amount of 40% by mass to 90% by mass, and more preferably 50% by mass to 85% by mass with respect to the total amount of the binder for inkjet printing ink.

  The binder for ink-jet printing ink of the present invention may be used in combination with a curing agent or a curing catalyst, if necessary, as long as storage stability and ink dischargeability are not deteriorated.

  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.

  Since the polyurethane composition containing the composite resin particles (A) and the aqueous medium (B) obtained by the above method can dramatically improve the scratch resistance and alkali resistance of the printed matter, it is exclusively for inkjet printing. It can be suitably used for an ink binder.

  The composite resin particles (A) are in the range of 10% by mass to 50% by mass with respect to the total amount of the binder for ink jet printing ink from the viewpoint of achieving both the storage stability of the ink, excellent scratch resistance, and alkali resistance. It is preferable that it is contained in the range of 15 mass%-40 mass%.

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, anthanthrone 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 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) 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 1000 nm or less, and preferably has a volume average particle diameter of 300 nm or less, and more particularly like photographic image quality. In the case of forming a high gloss image, the range of 80 to 120 nm is more preferable.

  Moreover, the said inkjet printing ink is 0.2 mass%-10 mass% of said hydrophilic group containing polyurethane (A), and 50 mass%-95 mass of aqueous medium (B) with respect to the whole inkjet printing ink. %, Pigment or dye is preferably contained in an amount of 0.5 to 15% by 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]
In a nitrogen-substituted container equipped with a thermometer, a nitrogen gas introduction tube, and a stirrer, polyether polyol ("Exenol 2020" polypropylene glycol manufactured by Asahi Glass Co., Ltd., number average molecular weight 2000) 601.3 parts by mass, 2, 2-dimethylolpropionic acid 48.4 parts by mass, 1,4-cyclohexanedimethanol 80.0 parts by mass and isophorone diisocyanate 270.3 parts by mass in the presence of 428.6 parts by mass of methyl ethyl ketone as an organic solvent for 5 hours Reacted.

  When the weight average molecular weight of the reactant reached the range of 20000 to 50000, the reaction was terminated by adding 7.8 parts by mass of methanol, and 563.7 parts by mass of methyl ethyl ketone was added as a diluting solvent. An organic solvent solution of polyurethane having a valence of 20 (nonvolatile content 50% by mass) 2000 parts by mass was obtained. In addition, the said acid value is the theoretical value computed based on the usage-amount of acid group containing compounds, such as 2, 2- dimethylol propionic acid used for manufacture of a polyurethane. In the following Examples and Comparative Examples, the acid value was calculated by the same method as described above unless otherwise specified.

[Example 1]
By adding 7.3 parts by mass of a 20% by mass aqueous ammonia solution to 483.8 parts by mass of the polyurethane organic solvent solution obtained in Preparation Example 1, some or all of the carboxyl groups of the polyurethane are neutralized, and An aqueous dispersion of polyurethane (a1-I) was obtained by adding 977.2 parts by mass of water and stirring sufficiently.
To an aqueous dispersion of the obtained polyurethane (a1-I), 8.1 parts by mass of an epoxy resin (“Epiclon 850” manufactured by DIC Corporation, bisphenol A type diglycidyl ether, epoxy equivalent 188) was added, and 80 ° C. For 6 hours to obtain an aqueous dispersion of composite resin particles (AI).

  Next, by aging and removing the aqueous dispersion of the composite resin particles (AI), the composite resin particles having an acid value of 10 and a gel fraction of 85 to 100% by mass and an average particle size of 10 to 70 nm. An ink-jet printing ink binder having a nonvolatile content of 25% by mass in which (AI) was dispersed in water was obtained.

[Example 2]
By adding 7.5 parts by mass of a 20% by mass aqueous ammonia solution to 493.4 parts by mass of the organic solvent solution of polyurethane obtained in Preparation Example 1, some or all of the carboxyl groups of the polyurethane are neutralized, and An aqueous dispersion of polyurethane (a1-II) was obtained by adding 972.4 parts by mass of water and stirring sufficiently.
To an aqueous dispersion of the obtained polyurethane (a1-II), 3.3 parts by mass of an epoxy resin (“Epiclon 850” manufactured by DIC Corporation, bisphenol A-type diglycidyl ether, epoxy equivalent 188) is added, and 80 ° C. Was reacted for 6 hours to obtain an aqueous dispersion of composite resin particles (A-II).
Next, by aging and removing the aqueous dispersion of the composite resin particles (A-II), the composite resin particles having an acid value of 16 and a gel fraction of 80 to 98% by mass and an average particle size of 10 to 70 nm. A binder for ink jet printing ink having a nonvolatile content of 25% by mass in which (A-II) was dispersed in water was obtained.

[Example 3]
By adding 7.2 parts by mass of a 20% by mass aqueous ammonia solution to 474.6 parts by mass of the polyurethane organic solvent solution obtained in Preparation Example 1, some or all of the carboxyl groups of the polyurethane are neutralized, and An aqueous dispersion of polyurethane (a1-III) was obtained by adding 981.9 parts by mass of water and stirring sufficiently.
12.7 parts by mass of epoxy resin (“Epiclon 850”, bisphenol A type diglycidyl ether, epoxy equivalent 188, which is an epoxy resin manufactured by DIC Corporation) was added to the aqueous dispersion of polyurethane (a1-III) obtained, and 80 By making it react at 6 degreeC for 6 hours, the aqueous dispersion of composite resin particle (A-III) was obtained.
Next, by aging and removing the aqueous dispersion of the composite resin particles (A-III), the composite resin particles having an acid value of 4 and a gel fraction of 90 to 100% by mass and an average particle size of 10 to 70 nm. A binder for ink jet printing ink having a nonvolatile content of 25% by mass in which (A-III) was dispersed in water was obtained.

[Example 4]
137.1 parts by mass of polyether polyol ("Exenol 2020" polypropylene glycol manufactured by Asahi Glass Co., Ltd., number average molecular weight 2000) in a nitrogen-substituted container equipped with a thermometer, a nitrogen gas introduction tube and a stirrer, 2-dimethylolpropionic acid 11.3 parts by mass, 1,4-cyclohexanedimethanol 17.9 parts by mass and isophorone diisocyanate 67.8 parts by mass in the presence of 100.3 parts by mass of methyl ethyl ketone as the organic solvent for 5 hours Reacted.

  After confirming that 95-100% of the isocyanate groups have been consumed by NCO titration, immediately terminate the reaction by adding 3.2 parts by mass of ethylenediamine, and further add 136.9 parts by mass of methyl ethyl ketone as a diluting solvent. Thus, an organic solvent solution of polyurethane (acid value 20) was obtained.

Next, 7.1 parts by mass of a 20% by mass aqueous ammonia solution was added to the total amount of the polyurethane organic solvent solution obtained above to neutralize part or all of the carboxyl groups of the polyurethane, and water 976.3 was further added. An aqueous dispersion of polyurethane (a1-IV) was obtained by adding part by mass and stirring sufficiently.
12.8 parts by mass of an epoxy resin ("Epiclon 850" bisphenol A diglycidyl ether, epoxy equivalent 188, which is an epoxy resin manufactured by DIC Corporation) was added to the aqueous dispersion of the obtained polyurethane (a1-IV). By reacting at 6 ° C. for 6 hours, an aqueous dispersion of composite resin particles (A-IV) was obtained.
Next, by aging and removing the aqueous dispersion of the composite resin particles (A-IV), the composite resin particles having an acid value of 16 and a gel fraction of 75 to 98% by mass and an average particle size of 20 to 200 nm. A binder for inkjet printing ink having a nonvolatile content of 25% by mass in which (A-IV) was dispersed in water was obtained.

[Example 5]
In a nitrogen-substituted container equipped with a thermometer, a nitrogen gas introduction tube, and a stirrer, polyether polyol ("Exenol 2020" polypropylene glycol manufactured by Asahi Glass Co., Ltd., number average molecular weight 2000) 146.9 parts by mass, 2, 2-dimethylolpropionic acid 29.3 parts by weight, 1,4-cyclohexanedimethanol 0.3 part by weight and isophorone diisocyanate 65.4 parts by weight in the presence of 103.7 parts by weight of methyl ethyl ketone as organic solvent for 5 hours Reacted.

When the weight average molecular weight of the reaction product reaches the range of 20000 to 50000, the reaction is terminated by adding 1.9 parts by mass of methanol, and 136.3 parts by mass of methyl ethyl ketone is added as a diluent solvent, so that polyurethane An organic solvent solution having an acid value of 50 was obtained.
Next, 18.3 parts by mass of a 20% by mass aqueous ammonia solution was added to the total amount of the polyurethane organic solvent solution obtained above to neutralize part or all of the carboxyl groups of the polyurethane, and water 975.0 An aqueous dispersion of polyurethane (a1-V) was obtained by adding parts by mass and stirring sufficiently.
To an aqueous dispersion of the obtained polyurethane (a1-V), 8.1 parts by mass of an epoxy resin (“Epiclon 850”, bisphenol A type diglycidyl ether, epoxy equivalent 188, manufactured by DIC Corporation) was added. By reacting at 6 ° C. for 6 hours, an aqueous dispersion of composite resin particles (AV) was obtained.
Next, by aging and removing the aqueous dispersion of the composite resin particles (AV), the composite resin particles having an acid value of 40, a gel fraction of 80 to 98% by mass, and an average particle size of 10 to 50 nm Vine for inkjet printing ink having a non-volatile content of 25% by mass in which (A-V) is dispersed in water

[Preparation Example 2]
In a nitrogen-substituted container equipped with a thermometer, a nitrogen gas introduction tube, and a stirrer, polyether polyol ("Exenol 2020" polypropylene glycol manufactured by Asahi Glass Co., Ltd., number average molecular weight 2000) 392.0 parts by mass, 2, 24.2 parts by mass of 2-dimethylolpropionic acid and 83.7 parts by mass of isophorone diisocyanate were reacted in the presence of 214.3 parts by mass of methyl ethyl ketone as an organic solvent for 5 hours.
When the weight average molecular weight of the reactant reached the range of 20000 to 50000, the reaction was terminated by adding 2.4 parts by mass of methanol, and 283.3 parts by mass of methyl ethyl ketone was added as a diluting solvent. 1000.0 parts by mass of an organic solvent solution of polyurethane with a valence of 20 (nonvolatile content: 50% by mass) was obtained.

[Example 6]
By adding 7.3 parts by mass of a 20% by mass aqueous ammonia solution to 483.8 parts by mass of the polyurethane organic solvent solution obtained in Preparation Example 2, part or all of the carboxyl groups of the polyurethane are neutralized, and An aqueous dispersion of polyurethane (a1-VI) was obtained by adding 197.2 parts by mass of water and stirring sufficiently.
To an aqueous dispersion of the obtained polyurethane (a1-VI), 8.1 parts by mass of an epoxy resin (“Epiclon 850” bisphenol A type diglycidyl ether, epoxy equivalent 188, manufactured by DIC Corporation) was added, and 80 An aqueous dispersion of composite resin particles (A-VI) was obtained by reacting at 6 ° C. for 6 hours.
Next, by aging and removing the aqueous dispersion of the composite resin particles (A-VI), the composite resin particles having an acid value of 10 and a gel fraction of 85 to 100% by mass and an average particle size of 10 to 70 nm. A binder for inkjet printing ink having a nonvolatile content of 25% by mass in which (A-VI) was dispersed in water was obtained.

[Example 7]
By adding 5.9 parts by mass of a 20% by mass aqueous ammonia solution to 485.2 parts by mass of the polyurethane organic solvent solution obtained in Preparation Example 1, some or all of the carboxyl groups of the polyurethane are neutralized, and An aqueous dispersion of polyurethane (a1-VII) was obtained by adding 976.5 parts by mass of water and stirring sufficiently.
7.4 parts by mass of an epoxy resin (epoxy resin, aliphatic polyglycidyl ether, epoxy equivalent 171 manufactured by “CR-5L” DIC Corporation) was added to the aqueous dispersion of the obtained polyurethane (a1-VII), and 80 ° C. Was reacted for 6 hours to obtain an aqueous dispersion of composite resin particles (A-VII).
Next, by aging and removing the aqueous dispersion of the composite resin particles (A-VII), a composite having an acid value of 10 and a gel fraction of 85% by mass to 100% by mass and an average particle size of 10 nm to 70 nm. A binder for ink jet printing ink having a nonvolatile content of 25% by mass in which resin particles (A-VII) were dispersed in water was obtained.

[Comparative Example 1]
By adding 7.6 parts by mass of a 20% by mass aqueous ammonia solution to 50.0 parts by mass of the organic solvent solution of polyurethane obtained in Preparation Example 2, some or all of the carboxyl groups of the polyurethane are neutralized, By adding 969.1 parts by mass of water and stirring sufficiently, an aqueous dispersion of polyurethane (a1′-I) was obtained.
Next, the aqueous dispersion of polyurethane (a1′-I) was aged and removed to remove polyurethane (a1′-I) having an acid value of 20 and a gel fraction of 45 to 85% by mass and an average particle size of 10 to 70 nm. A binder for ink jet printing ink having a nonvolatile content of 25% by mass containing I) was obtained.

[Comparative Example 2]
In a nitrogen-substituted container equipped with a thermometer, a nitrogen gas introduction tube, and a stirrer, polyether polyol ("Exenol 2020" polypropylene glycol manufactured by Asahi Glass Co., Ltd., number average molecular weight 2000) 191.5 parts by mass, 2, 12.1 parts by mass of 2-dimethylolpropionic acid and 45.4 parts by mass of isophorone diisocyanate were reacted in the presence of 106.7 parts by mass of methyl ethyl ketone as an organic solvent for 5 hours.

  After confirming that 95 to 100% of the isocyanate groups were consumed by NCO titration, an organic solvent solution of polyurethane (acid value 20) (nonvolatile content 50 mass) was further added by adding 142.3 parts by mass of methyl ethyl ketone as a diluent solvent. %).

7.6 parts by mass of a 20% by mass aqueous ammonia solution is added to the total amount of the organic solvent solution of polyurethane obtained above to neutralize part or all of the carboxyl groups of the polyurethane, and further 965.0 parts by mass of water The mixture was stirred for several minutes, and then 1.0 part by mass of diethyleneamine was added and stirred sufficiently to perform chain elongation to obtain an aqueous dispersion of polyurethane (a1′-II).
Next, the aqueous dispersion of polyurethane (a1′-II) is aged and desolvated to give a polyurethane (a1′-) having an acid value of 20 and a gel fraction of 45 to 85% by mass and an average particle size of 10 to 70 nm. A binder for ink jet printing ink having a nonvolatile content of 25% by mass containing II) was obtained.

[Measurement of Weight Average Molecular Weight of Polyurethane (a1)]
The weight average molecular weight of the polyurethane was measured using a gel permeation chromatograph (GPC method). Specifically, the binder for inkjet printing ink obtained above 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 of the coating film dissolved in 100 g of tetrahydrofuran was used as 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%.

[Measurement method of average particle size]
The average particle diameter of the composite resin particles (A) was a 50% median diameter on a volume basis, and was measured using a Microtrac UPA250 particle size distribution measuring apparatus manufactured by Nikkiso Co., Ltd. using a dynamic light scattering method.

[Measurement method of gel fraction]
A film having a length of 3 cm, a width of 3 cm, and a thickness of 150 μm was prepared using the binder for ink jet printing ink obtained in Examples and Comparative Examples, and the mass (M) thereof was measured. Next, after immersing the film in methyl ethyl ketone adjusted to 25 ° C. for 24 hours, the residue of the film that did not dissolve in methyl ethyl ketone was separated by filtration through a 300 mesh wire mesh, and the residue was dried at 108 ° C. for 1 hour. The mass (N) of the product was measured. Next, the gel fraction was calculated by calculating based on the formula [(N) / (M)] × 100 using the values of the masses (M) and (N).

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 Was charged into a planetary mixer PLM-V-50V (manufactured by Inoue Seisakusho Co., Ltd.) having a capacity of 50 L, 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 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., Rotating speed: 2660 rev / min), the bead mill passing liquid is centrifuged at 13000 G × 10 minutes, and then filtered through a filter having an effective pore size of 0.5 μm to thereby obtain a water-based quinacridone pigment. A dispersion was obtained. The concentration of the quinacridone pigment in this aqueous pigment dispersion was 14.9% by mass.

[Preparation of ink for inkjet printing]
In the preparation example 1, the binder for the inkjet printing ink obtained in Examples 1 to 7 and Comparative Examples 1 and 2 so that the concentration of the quinacridone pigment is 4% by mass and the concentration of the polyurethane is 1% by mass. The obtained quinacridone pigment, 2-pyrrolidinone, triethylene glycol monobutyl ether, glycerin, surfactant (Surfinol 440, manufactured by Air Products) and ion-exchanged water were mixed and stirred according to the following blending ratio. By doing so, an ink for inkjet printing was prepared.

(Mixing ratio of ink for inkjet printing)
-Quinacridone pigment aqueous dispersion obtained in Preparation Example 1 (pigment concentration: 14.9%); 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 7 and Comparative Examples 1 and 2 (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 of the ink for inkjet printing obtained above was measured using a VISCOMETER TV-22 manufactured by Toki Sangyo Co., Ltd. The particle size of the dispersed particles in the ink for inkjet printing ink was measured using Microtrack UPA EX150 manufactured by Nikkiso Co., Ltd.

  Next, the ink is sealed in a glass container such as a screw tube, a heating test is performed for 4 weeks with a thermostat at 70 ° C., and the viscosity and particle diameter of the ink after the heating test are measured by the same method as described above. did.

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

(Formula I)
[(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

(Formula II)
[(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

[Evaluation of ink ejection stability]
A diagnostic page was printed using a Photomart D5360 (manufactured by Hewlett Packard) in which a black ink cartridge was filled with the ink for inkjet printing, and the state of the nozzle was confirmed.
Next, 20 pages of solid printing with a printing density setting of 100% in an area of 18 cm × 25 cm per page were continuously performed, and then 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 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 completed solid printing

[Evaluation of printing performance of ink for inkjet printing]
(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 ink is filled into the black ink cartridge. The printed matter for evaluation was obtained by 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 or 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, the printed matter for evaluation could not be obtained, and those that could not be evaluated were marked with “−” in the table.

[Criteria]
A: The printed surface was not damaged at all, and the printing material was not peeled off.
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.

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

(Alcohol resistance)
After the printed matter for evaluation was dried at room temperature for 10 minutes, 3 drops of a 5% by mass ethanol aqueous solution was dropped onto the printed surface with a dropper, and after 10 seconds, the printed surface was rubbed with a finger to visually check the surface state of the printed surface. It was evaluated with. The evaluation criteria are described below. In addition, since the ejection stability of the ink was insufficient, the printed matter for evaluation could not be obtained, and those that could not be evaluated were marked with “−” 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.

  “E850” in Tables 1 and 2 indicates bisphenol A type diglycidyl ether, epoxy equivalent 188 (Epiclon 850), which is an epoxy resin manufactured by DIC Corporation. “CR-5L” indicates an aliphatic polyglycidyl ether, epoxy equivalent 171 which is an epoxy resin manufactured by DIC Corporation.

Claims (10)

And inkjet printing inks binders, a pigment or dye, a styrene - an ink jet printing ink containing an acrylic resin, the ink-jet printing ink binder comprises a polyether-based polyurethane (a1), aliphatic polyglycidyl An ink for inkjet printing, wherein composite resin particles (A) formed by reaction with an epoxy compound (a2) containing ether or bisphenol-based glycidyl ether are dispersed in an aqueous medium (B). The composite resin particle (A) is obtained by reacting the functional group [X] of the polyether-based polyurethane (a1) with the epoxy group [Y] of the epoxy compound (a2). Item 10. The ink for inkjet printing according to Item 1. The ink for inkjet printing according to claim 2, wherein the functional group [X] of the polyether-based polyurethane (a1) is an amino group . The ink for inkjet printing according to claim 1, wherein the composite resin particles (A) have an acid value of 1 mgKOH / g to 50 mgKOH / g. The molar ratio of the functional group [X] of the polyether polyurethane (a1) and the epoxy group [Y] of the epoxy compound (a2) constituting the composite resin particle (A) [epoxy group [Y]. 2. The ink for inkjet printing according to claim 1, wherein the / functional group [X]] is in a range of 1/20 to 1/1. The ink for inkjet printing according to claim 1, wherein the composite resin particles (A) have an average particle diameter in the range of 10 nm to 1000 nm. The ink for inkjet printing according to claim 1, wherein the polyether-based polyurethane (a1) has a weight average molecular weight in the range of 5,000 to 200,000. The ink for inkjet printing of Claim 1 whose said epoxy compound (a2) is a compound which has an epoxy equivalent of 100-2000. Formed by reaction of an ink precursor containing a pigment or dye, a styrene-acrylic resin, and a polyether polyurethane (a1) with an epoxy compound (a2) containing an aliphatic polyglycidyl ether or a bisphenol glycidyl ether. A method for producing an ink for ink jet printing, comprising mixing a binder for ink for ink jet printing in which the composite resin particles (A) dispersed in an aqueous medium (B) are mixed. A printed matter printed with the ink for inkjet printing according to any one of claims 1 to 8 .