WO2012042968A1

WO2012042968A1 - Binder for ink-jet printing ink, ink-jet printing ink containing same, and printed matter

Info

Publication number: WO2012042968A1
Application number: PCT/JP2011/061849
Authority: WO
Inventors: 定永浜
Original assignee: Dic株式会社
Priority date: 2010-09-29
Filing date: 2011-05-24
Publication date: 2012-04-05
Also published as: JPWO2012042968A1; JP5029932B2; TW201224096A

Abstract

The present invention addresses the problem of providing: a binder for ink-jet printing inks which are capable of forming printed images having durability, such as extremely high scratch resistance and alkali resistance, while retaining intact properties including satisfactory delivery stability and storage stability; and an ink-jet printing ink containing the binder. This binder for ink-jet printing inks is characterized by comprising an aqueous medium (B) and, dispersed therein, composite resin particles (A) formed through reactions among an isocyanate-group-containing polyurethane (a1), a polyisocyanate (a2) other than the isocyanate-group-containing polyurethane (a1), and a polyamine (a3). The invention further relates to printed matter.

Description

Ink jet printing ink binder, ink jet printing ink containing the same, and printed matter

The present invention relates to an ink binder usable for 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.)

The image obtained by printing using the ink jet recording ink had a certain degree of scratch resistance, such as preventing 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 cross-linked in the particles as the binder and have a high molecular weight. The use of the modified resin particles was considered and could be solved by the investigation.

As a result, when the binder for inkjet printing ink in which the composite resin particles in which the intraparticle crosslinking has progressed is dispersed in an aqueous medium by reacting the isocyanate group-containing polyurethane, polyisocyanate, and polyamine is used, good ink ejection is achieved. It has been found that the scratch resistance and alkali resistance can be improved without impairing the stability and storage stability.

That is, in the present invention, the composite resin particles (A) formed by reacting the isocyanate group-containing polyurethane (a1), the polyisocyanate (a2) other than the isocyanate group-containing polyurethane (a1), and the polyamine (a3), The present invention relates to a binder for ink jet printing ink, which is dispersed in an aqueous medium (B), an ink for ink jet printing containing the binder, and a printed matter.

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.

In the present invention, the composite resin particles (A) formed by reacting the isocyanate group-containing polyurethane (a1), the polyisocyanate (a2) other than the isocyanate group-containing polyurethane (a1), and the polyamine (a3) are formed into an aqueous medium. It is the binder for inkjet printing inks disperse | distributed to (B).

The composite resin particles (A) used in the present invention are formed by a cross-linking reaction between the isocyanate group-containing polyurethane (a1), polyisocyanate (a2), and polyamine (a3).

The isocyanate group-containing polyurethane (a1), the polyisocyanate (a2), and the polyamine (a3) are crosslinked by the isocyanate group [X1] of the isocyanate group-containing polyurethane (a1) and the polyisocyanate (a2). This is a reaction between an isocyanate group [X2] and an amino group [Y] of the polyamine (a3).

More specifically, in the crosslinking reaction, the isocyanate group [X1] of the isocyanate group-containing polyurethane (a1) and the isocyanate group [X2] of the polyisocyanate (a2) are converted into those of the polyamine (a3). It is a reaction capable of forming a urea bond by reacting with each of the amino groups [Y].

As the composite resin particles (A), it is preferable to use composite resin particles that are cross-linked at high density inside the particles from the viewpoint of imparting even better scratch resistance and the like. If the composite resin particles, since a cross-linked structure is formed in the particles, it is difficult to cause swelling of the particles due to the aqueous medium (B) and the like, and as a result, the ink ejection stability is excellent without being impaired. It is possible to impart abrasion resistance 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 the composite resin particles (A), the molar ratio of the isocyanate group [X1] of the isocyanate group-containing polyurethane (a1) and the isocyanate group [X2] of the polyisocyanate (a2) [isocyanate group [X1] / isocyanate Group [X2]] is preferably in the range of 0.1 to 20, more preferably 0.1 to 9, and the amino group [Y], the isocyanate group [X1] and the isocyanate group [X2] And the total molar ratio [amino group [Y] / {sum of isocyanate group [X1] and isocyanate group [X2]}] is preferably in the range of 0.3 to 3, The isocyanate group-containing polyurethane (a1), the polyisocyanate (a2), and the polyamine (a3) were mixed and subjected to a crosslinking reaction within the range of The use of the is preferable for both the excellent discharge stability and storage stability of the ink, and excellent abrasion resistance and alkali resistance.

In addition, as the composite resin particles (A), part or all of the polyisocyanate (a2) and the polyamine (a3) are inherently contained in the resin particles (a) formed by the isocyanate group-containing polyurethane (a1). And it is preferable to use what cross-linked in the said resin particle (a).
As the composite resin particles (A), all of the polyisocyanate (a2) and polyamine (a3) are not present in the polyurethane (a1) resin particles (a), or one of them is not subjected to a crosslinking reaction. May be present in the shell layer of the resin particles (a), or may be present in the aqueous medium (B) independently of the composite resin particles (A), but the polyisocyanate (a2) And 90% by mass or more of the total mass of the polyamine (a3) is preferably present in the composite resin particles (A) and subjected to a crosslinking reaction, and more preferably 95% by mass or more.

As the composite resin particles (A), those having a hydrophilic group are preferably used from the viewpoint of being stably dispersed in the aqueous medium (B).

More specifically, as the composite resin particles (A), those having a hydrophilic group as the isocyanate group-containing polyurethane (a1) are used, and the resin particles (a) formed by the polyurethane (a1) are used. It is preferable to use those in which a part or all of the polyisocyanate (a2) and the polyamine (a3) are present and cross-linked within the resin particles (a).
Also when using what has a hydrophilic group as said composite resin particle (A), all of said polyisocyanate (a2) and polyamine (a3) are in said polyurethane (a1) resin particle (a) similarly to the above. Some of them are present in the shell layer of the resin particles (a) without being present or cross-linking reaction, or in the aqueous medium (B) independently of the composite resin particles (A). It may be present, but 90% by mass or more of the total mass of the polyisocyanate (a2) and the polyamine (a3) is preferably present in the composite resin particles (A) and subjected to a crosslinking reaction, What is more than the mass% is more preferable.

As the hydrophilic group, an anionic group, a cationic group, and a nonionic group can be used. Among these, an anionic group or a cationic group is more preferable, and an anionic group is particularly preferable. preferable.

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

The hydrophilic group is preferably present in the range of 15 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.

In addition, as the composite resin particles (A), those having an acid value of 1 mgKOH / g to 70 mgKOH / g are preferably used from the viewpoint of maintaining good storage stability and ejection stability. In particular, it is more preferable to use one having an acid value of 10 mgKOH / g to 40 mgKOH / g from the viewpoint of maintaining good storage stability and ejection stability and improving alkali resistance. The acid value is preferably derived from an acid group such as a carboxyl group that the isocyanate group-containing polyurethane (a1) can have.

The isocyanate group-containing polyurethane (a1) used for the production of the composite resin particles (A) will be described.

As the isocyanate group-containing polyurethane (a1), those having an isocyanate group [X1] as a functional group capable of reacting with an amino group [Y] of a polyamine (a3) described later are used.

As the polyurethane (a1), those having the isocyanate group [X1] at the molecular one end, both ends or molecular side chains of the polyurethane (a1) can be used.

The isocyanate group equivalent of the polyurethane (a1) is preferably in the range of 500 to 50,000.

The isocyanate group-containing polyurethane (a1) is preferably one having a hydrophilic group from the viewpoint of imparting good water dispersion stability to the composite resin particles (A).

As the hydrophilic group, an anionic group, a cationic group, and a nonionic group can be used. Among these, an anionic group or a cationic group is more preferable, and an anionic group is particularly preferable. .

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

The hydrophilic group is preferably present in the range of 50 to 2000 mmol / kg, and preferably in the range of 150 to 1500 mmol / kg, with respect to the whole isocyanate group-containing polyurethane (a1). It is more preferable in giving.

Further, as the isocyanate group-containing polyurethane (a1), it is possible to use a polyurethane having a weight average molecular weight of 1,000 to 100,000, which has excellent alcohol resistance as well as excellent scratch resistance and alkali resistance. It is preferable for forming a printed image and imparting good ink ejection stability, and more preferably having a weight average molecular weight in the range of 1,000 to 50,000.

The isocyanate group-containing polyurethane (a1) can be produced, for example, by reacting the polyol (a1-1) and the polyisocyanate (a1-2) with a chain extender or the like, if necessary, as raw materials. it can.

As the polyol (a1-1), for example, polyether polyol, polyester polyol, polyester ether polyol, polycarbonate polyol and the like can be used. Among these, it is more preferable to use a polyether polyol in order to improve the storage stability of the binder for ink jet printing ink.

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, bisphenol A, bisphenol F, bisphenol B, bisphenol AD, and the like can be used.

Further, as the alkylene oxide, for example, ethylene oxide, propylene oxide, butylene oxide, styrene oxide, epichlorohydrin, tetrahydrofuran, or the like can be used.

Specifically, it is more preferable to use polyoxytetramethylene glycol or polyoxypropylene glycol as the polyether polyol in order to improve ink ejection stability. Further, as the polyether polyol, those having a number average molecular weight of 300 to 2,000 are preferably used, and those having a number average molecular weight of 800 to 1500 are excellent in ink ejection stability, scratch resistance and alcohol resistance. And more preferable.

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

As the low molecular weight polyol, for example, ethylene glycol, propylene glycol and the like can be used.

As the polycarboxylic acid, for example, succinic acid, adipic acid, sebacic acid, dodecanedicarboxylic acid, terephthalic acid, isophthalic acid, phthalic acid, and anhydrides or ester-forming derivatives thereof can be used.

Further, as the polyester ether polyol, for example, a reaction product of a polyether polyol obtained by adding the alkylene oxide to the initiator and a polycarboxylic acid can be used. As the initiator and the alkylene oxide, the same ones exemplified as those usable when the polyether polyol is produced can be used. Moreover, as said polycarboxylic acid, the thing similar to what was illustrated as what can be used when manufacturing the said polyester polyol can be used.

Further, as the polycarbonate polyol, for example, those obtained by reacting a carbonic acid ester and a polyol, or those obtained by reacting phosgene with bisphenol A or the like can be used.

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, triethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, dipropylene glycol, 1,4-butanediol, 1,3- Butanediol, 1,2-butanediol, 2,3-butanediol, 1,5-pentanediol, 1,5-hexanediol, 2,5-hexanediol, 1,6-hexanediol, 1,7-heptane Diol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, 3-methyl-1,5-pentanediol, 2- Ethyl-1,3-hexanediol, 2-methyl-1,3-pro Diol, 2-methyl-1,8-octanediol, 2-butyl-2-ethylpropanediol, 2-methyl-1,8-octanediol, neopentyl glycol, 1,4-cyclohexanediol, 1,4-cyclohexane Relatively low molecular weight dihydroxy compounds such as dimethanol, hydroquinone, resorcin, bisphenol-A, bisphenol-F, 4,4′-biphenol, polyether polyols such as polyethylene glycol, polypropylene glycol, polytetramethylene glycol, Polyester polyols such as hexamethylene adipate, polyhexamethylene succinate, and polycaprolactone can be used.

The polyether polyol, polyester polyol, polyester ether polyol, and polycarbonate polyol are used in a total range of 15% by mass to 85% by mass with respect to the total mass of raw materials used for the production of the isocyanate group-containing polyurethane (a1). It is preferable.

As the polyol (a1-1), a hydrophilic group-containing polyol can be used for the purpose of introducing the hydrophilic group into the isocyanate group-containing polyurethane (a1).

As the hydrophilic group-containing polyol, a polyol having a hydrophilic group other than the polyether polyol, polyester polyol, polyester ether polyol and polycarbonate polyol can be used. For example, an anionic group-containing polyol, a cationic group-containing polyol can be used. A polyol and a nonionic group-containing polyol can be used, and among them, an anionic group-containing polyol and a cationic group-containing polyol are preferably used, and an anionic group-containing polyol is particularly preferably used.

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

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, the carboxyl group-containing polyester polyol obtained by making the said carboxyl group-containing polyol and various polycarboxylic acids react can also be 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 polyether polyol. The polyester polyol obtained by making it react with the low molecular weight polyol similar to what was illustrated as an initiator which can be used when manufacturing can be used.

The carboxyl group-containing polyol or sulfonic acid group-containing polyol is preferably used in the range where the acid value of the isocyanate group-containing polyurethane (a1) is 1 mgKOH / g to 70 mgKOH / g, and is 10 mgKOH / g to 40 mgKOH / g. It is particularly preferable to use in a range. In addition, the acid value said by this invention is the theoretical value computed based on the usage-amount of acid group containing compounds, such as a carboxyl group containing polyol used for manufacture of the said isocyanate group containing polyurethane (a1).

The anionic group is preferably partially or completely neutralized with a basic compound or the like in order to develop good water dispersibility.

Examples of basic compounds that can be used for neutralizing the anionic group include organic amines having a boiling point of 200 ° C. or higher, such as ammonia, triethylamine, morpholine, monoethanolamine, and diethylethanolamine, NaOH, KOH, and LiOH. A metal hydroxide containing etc. can be used. From the viewpoint of improving the dispersion stability of the resulting ink, the basic compound is preferably used in the range of basic compound / anionic group = 0.5 to 3.0 (molar ratio). It is more preferable to use in the range of 5 to 1.5 (molar ratio).

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 per molecule, and a secondary amine can be used. A polyol obtained by reacting with can be used.

The cationic group is preferably partially or completely neutralized with an acidic compound such as formic acid, acetic acid, phosphoric acid, propionic acid, succinic acid, glutaric acid, tartaric acid and adipic acid.

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

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 is preferably used in the range of 1% by mass to 50% by mass with respect to the total mass of raw materials used for the production of the isocyanate group-containing polyurethane (a1).

Further, as the polyol (a1-1), other polyols having a relatively low molecular weight can be used as necessary in addition to those described above.

The other polyol has a molecular weight of about 100 to 500, and for example, ethylene glycol or propylene glycol can be used.

In addition, as the other polyols, for example, aliphatic cyclic structure-containing polyols such as 1,4-cyclohexanediol, cycloheptanediol, and cyclohexanedimethanol can be used.

Examples of the polyisocyanate (a1-2) that can be used for the production of the isocyanate group-containing polyurethane (a1) include 4,4′-diphenylmethane diisocyanate, 2,4′-diphenylmethane diisocyanate, carbodiimide-modified diphenylmethane diisocyanate, and crude diphenylmethane. Aromatic polyisocyanates such as diisocyanate, phenylene diisocyanate, tolylene diisocyanate, naphthalene diisocyanate, and aliphatic polyisocyanates such as hexamethylene diisocyanate, lysine diisocyanate, cyclohexane diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, xylylene diisocyanate, tetramethylxylylene diisocyanate Isocyanate There may be used a polyisocyanate having 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 polyisocyanate (a1-2) is preferably a single polyisocyanate rather than a multimer such as nurate.

The isocyanate group-containing polyurethane (a1) can be produced, for example, by reacting the polyol (a1-1) and the polyisocyanate (a1-2) in the absence of a solvent or in the presence of an organic solvent. The reaction is preferably performed in the range of about 40 ° C. to 100 ° C. for about 1 hour to 10 hours. When a chain extender is used as necessary, it may be used by mixing with the polyol (a1-1) or the polyisocyanate (a1-2).

The reaction between the polyol (a1-1) and the polyisocyanate (a1-2) is, for example, that the equivalent ratio of the isocyanate group of the polyisocyanate (a1-2) to the hydroxyl group of the polyol (a1-1) is , Preferably in the range of 0.8 to 2.5, more preferably in the range of 0.9 to 1.5.

Examples of the organic solvent that can be used in producing the isocyanate group-containing polyurethane (a1) include ketones such as acetone and methyl ethyl ketone; ethers such as tetrahydrofuran and dioxane; and acetates such as ethyl acetate and butyl acetate. Nitriles such as acetonitrile; amides such as dimethylformamide and N-methylpyrrolidone can be used alone or in combination of two or more. When the organic solvent is used, it is preferable to remove the organic solvent by a method such as distillation from the viewpoint of reducing the environmental load.

When manufacturing the said isocyanate group containing polyurethane (a1), a chain extender can be used as needed for the purpose of enlarging the molecular weight from a viewpoint of improving abrasion resistance.
When the chain extender is used, for example, an isocyanate group-containing polyurethane prepolymer is prepared by reacting the polyol (a1-1) with the polyisocyanate (a1-2) in the absence of a solvent or in the presence of an organic solvent. An isocyanate group-containing polyurethane (a1) can be produced by producing a polymer and then reacting the polyurethane with a chain extender.

As the chain extender that can be used for producing the isocyanate group-containing polyurethane (a1), 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, 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; disuccinate Dorazide, 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, polyamine having two amino groups is preferably used, and ethylenediamine is more preferably used.

Examples of the other active hydrogen-containing compounds include ethylene glycol, diethylene recall, triethylene glycol, propylene glycol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, hexamethylene glycol, and saccharose. , Glycols such as methylene glycol, glycerin and 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 the range of 0.3 to 1.0 (equivalent ratio).

Since the isocyanate group-containing polyurethane obtained 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.

The isocyanate group-containing polyurethane (a1) obtained above is the total mass of raw materials used in the production of the composite resin particles (A), that is, the isocyanate group-containing polyurethane (a1), the polyisocyanate (a2), and the It is preferably used in the range of 50% by mass to 99% by mass and more preferably in the range of 80% by mass to 95% by mass with respect to the total mass of the polyamine (a3).

Next, the polyisocyanate (a2) used for producing the composite resin particles (A) used in the present invention will be described.

The polyisocyanate (a2) is a compound having two or more isocyanate groups, and refers to a compound other than the isocyanate group-containing polyurethane (a1).

Examples of the polyisocyanate (a2) include aromatic polyisocyanates such as 4,4′-diphenylmethane diisocyanate, 2,4′-diphenylmethane diisocyanate, carbodiimide-modified diphenylmethane diisocyanate, crude diphenylmethane diisocyanate, phenylene diisocyanate, tolylene diisocyanate, and naphthalene diisocyanate. Or aliphatic or alicyclic polyisocyanates such as hexane diisocyanate, hexamethylene diisocyanate, lysine diisocyanate, cyclohexane diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, xylylene diisocyanate, tetramethylxylylene diisocyanate, or those A dimer or the like, generally those referred to as cyanurate and can be used a mixture thereof. Moreover, as said polyisocyanate (a2), the thing in which two or more nurate partly formed the urethane bond, and the mixture containing it can be used.

Among the above-mentioned polyisocyanates (a2), it is preferable to use a nurate form, and more specifically, a dimer to pentamer form is more preferable. It is preferable to use a body to a pentamer in order to achieve both the ejection stability and storage stability of the ink and the scratch resistance and alkali resistance.

As the polyisocyanate (a2), a mixture of various polyisocyanates described above may be used. When such a mixture is used, the average number of isocyanate groups in the mixture is preferably in the range of 2 to 6. The average number of isocyanate groups is an average value calculated based on the mass of each polyisocyanate and the number of functional groups.

The nurate body can be produced, for example, by reacting the aromatic polyisocyanate, aliphatic polyisocyanate, alicyclic polyisocyanate, or the like in the presence of a plasticizer and a catalyst.

As the plasticizer, for example, in an inert solvent such as methyl acetate, ethyl acetate, butyl acetate, methyl ethyl ketone, dioxane, or diethyl phthalate, dibutyl phthalate, di-2-ethylhexyl phthalate, trimellitic acid ester, etc. can be used. .

As the catalyst, for example, a tertiary amine, a quaternary ammonium compound, a Mannich base, an alkali metal of a fatty acid, an alcoholate, or the like can be used.

As the polyisocyanate (a2), it is preferable to use a polyisocyanate (a2) having a number average molecular weight of 300 to 5,000 in order to achieve both the ejection stability and storage stability of the ink and the scratch resistance and alkali resistance. .

Part or all of the polyisocyanate (a2) is inherent in the resin particles (a) formed by the isocyanate group-containing polyurethane (a1), and is crosslinked with the polyurethane (a1) or the polyamine (a3). From the viewpoint of forming the composite resin particles (A), it is preferable that the polyisocyanate (a2) alone has a hydrophobicity level that cannot be stably dispersed in the aqueous medium (B). Specifically, the content of the hydrophilic group in the polyisocyanate (a2) is preferably less than 50 mmol / kg, preferably 25 mmol / kg or less, and particularly preferably 0 mmol / kg. .

The polyisocyanate (a2) is used in the range of 0.5% by mass to 20% by mass with respect to the total mass of the isocyanate group-containing polyurethane (a1), the polyisocyanate (a2), and the polyamine (a3). It is preferable to achieve both the ejection stability and storage stability of the ink and the scratch resistance and alkali resistance, and more preferably 0.5 to 10% by mass.

Next, the polyamine (a3) used for producing the composite resin particles (A) used in the present invention will be described.

The polyamine (a3) is a compound having two or more amino groups [Y], and the isocyanate group-containing polyurethane (a1) or the polyisocyanate (a2) has an isocyanate group [X1] or [X2]. It can react. The amino group [Y] is preferably a primary amino group or a secondary amino group from the viewpoint of promptly crosslinking with the isocyanate group [X1] or the isocyanate group [X2].
The reaction of the amino group [Y] with the isocyanate group [X1] or the isocyanate group [X2] proceeds to form the composite resin particles (A), thereby improving the ink ejection stability and storage stability. It is possible to obtain an ink jet printing ink binder capable of forming a printed image having excellent durability such as scratch resistance and alkali resistance without damaging.

Examples of the polyamine (a3) include ethylenediamine, 1,2-propanediamine, 1,6-hexamethylenediamine, piperazine, 2,5-dimethylpiperazine, isophoronediamine, 4,4′-dicyclohexylmethanediamine, 3, Diamines such as 3′-dimethyl-4,4′-dicyclohexylmethanediamine and 1,4-cyclohexanediamine; N-hydroxymethylaminoethylamine, N-hydroxyethylaminoethylamine, N-hydroxypropylaminopropylamine, N-ethyl Aminoethylamine, N-methylaminopropylamine; diethylenetriamine, dipropylenetriamine, triethylenetetramine; hydrazine, N, N′-dimethylhydrazine, 1,6-hexamethylenebishydrazine; Succinic acid dihydrazide, 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, Polyoxyalkylene triamines such as 5,5-trimethylcyclohexane and polyoxypropylene triamine which are commercially available as Jeffamine T403 (manufactured by HUNTSMAN) can be used. Among these, it is preferable to use a polyamine having 3 or more amino groups, and the amino group is more preferably a primary amino group. Specifically, it is more preferable to use diethylenetriamine or the polyoxyalkylenetriamine because it has three primary amines having high reactivity with the isocyanate group.

Part or all of the polyamine (a3) is inherent in the resin particles (a) formed by the isocyanate group-containing polyurethane (a1), and is crosslinked with the polyurethane (a1) or the polyisocyanate (a2). Thus, when forming the composite resin particles (A), it is preferable that the polyamine (a3) alone has a hydrophobicity at a level that cannot be stably dispersed in the aqueous medium (B). Specifically, the content of hydrophilic groups other than amino groups in the polyamine (a3) is preferably less than 50 mmol / kg, preferably 25 mmol / kg or less, and 0 mmol / kg. Is particularly preferred. The amino group in the polyamine (a3) reacts immediately with the isocyanate groups [X1] and [X2] in the aqueous medium (B) to form a urea bond, thereby substantially imparting water dispersibility. Does not contribute.

The polyamine (a3) is used in the range of 0.5% by mass to 30% by mass with respect to the total mass of the isocyanate group-containing polyurethane (a1), the polyisocyanate (a2), and the polyamine (a3). It is preferable to achieve both the ejection stability and storage stability of the ink and the scratch resistance and alkali resistance, and more preferably 0.5 to 15% by mass.

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) can be 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 process of producing the composite resin particles (A), when the aqueous medium (B) is used as a solvent, the aqueous medium (B) can be continuously used as a solvent for the binder for inkjet printing ink of the present invention. .

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

Inkjet printing ink in which composite resin particles (A) obtained by reacting the isocyanate group-containing polyurethane (a1), polyisocyanate (a2) and polyamine (a3) obtained above are dispersed in an aqueous medium (B) Examples of the method for producing the binder for use include the following [Method 1] to [Method 2].

The [Method 1] includes, for example, a step (I) for producing a mixture of the isocyanate group-containing polyurethane (a1) and the polyisocyanate (a2), and the mixture and the aqueous medium (B) are mixed and dispersed. And the step (II) of producing composite resin particles (A) in which the dispersion and the polyamine (a3) are mixed and crosslinked in the particles.

[Method 2] includes the step (IV) for producing a mixture of the isocyanate group-containing polyurethane (a1) and the polyisocyanate (a2), and the aqueous medium (B) and the polyamine separately from the step (IV). (A3) is mixed with the step (V) to obtain a mixture, and the mixture obtained in the step (IV) and the mixture obtained in the step (V) are mixed to obtain an isocyanate group-containing polyurethane (a1). This is a method comprising a step (VI) of producing an aqueous dispersion of composite resin particles (A) in which the polyisocyanate (a2) or the polyamine (a3) is crosslinked in the formed resin particles.

Among these, it is preferable to produce the composite resin particles (A) by the method [Method 1] from the viewpoint of suppressing gelation during the production and improving the production efficiency. Hereinafter, [Method 1] will be described in more detail.

Step (I) in [Method 1] is a step in which the isocyanate group-containing polyurethane (a1) obtained above and the polyisocyanate (a2) are mixed to obtain a mixture thereof. When the production of the isocyanate group-containing polyurethane (a1) is carried out in the presence of an organic solvent, the organic solvent solution of the isocyanate group-containing polyurethane (a1) and the polyisocyanate (a2) may be mixed. The organic solvent is preferably removed by a method such as distillation after the production of the ink jet ink binder of the present invention.

Step (II) in [Method 1] is a mixture of the isocyanate group-containing polyurethane (a1) obtained in the step (I) and the polyisocyanate (a2), and an aqueous medium (B), This is a step of producing a dispersion in which the isocyanate group-containing polyurethane (a1) and the polyisocyanate (a2) are dispersed in an aqueous medium (B).

Here, the polyisocyanate (a2) may not be stably dispersed in the aqueous medium (B) alone. In such a case, part or all of the polyisocyanate (a2) may be present in a localized state in the resin particles formed by the isocyanate group-containing polyurethane (a1).

In the case where the isocyanate group-containing polyurethane (a1) contained in the mixture has the hydrophilic group, before mixing the mixture and the aqueous medium (B), It is preferable to neutralize part or all of the hydrophilic group with a compatibilizer or a quaternizing agent in order to impart good water dispersion stability.

Step (III) in [Method 1] is a step of producing a composite resin particle (A) obtained by mixing and crosslinking the dispersion obtained in the step (II) and the polyamine (a3).

The polyamine (a3) may be partly or wholly localized in the resin particles formed by the isocyanate group-containing polyurethane (a1).

Thereby, composite resin particles (A) in which the isocyanate group-containing polyurethane (a1), the polyisocyanate (a2), and the polyamine (a3) are cross-linked in the resin particles can be formed.

In the binder for inkjet printing ink in which the composite resin particles (A) obtained by the above method are dispersed in the aqueous medium (B), a curing agent or A curing catalyst may be used in combination.

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

The ink binder for ink-jet printing 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.

The composite resin particle (A) is in the range of 10% by mass to 60% 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 preferably contained in the range of 15% by mass to 50% by 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 pigments 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.

These pigments can be used in combination of two or more. 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 an inkjet printing ink, and, if necessary, the additive with 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 in the production of 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.

In the ink for inkjet printing obtained by the above method, coarse particles having a particle diameter of approximately 250 nm or more may be present. 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, particularly in the case of forming a higher gloss image such as photographic image quality, the range of 80 to 500 nm. It is more preferable that

Further, the ink for ink jet printing is 0.2% by mass to 10% by mass of the hydrophilic group-containing polyurethane (A) and 50% by mass to 95% by mass of the aqueous medium (B) with respect to the whole ink for ink jet printing. %, 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.

[Example 1]
In a nitrogen-substituted container equipped with a thermometer, a nitrogen gas introduction tube, and a stirrer, 141.4 parts by mass of polyoxypropylene glycol having a number average molecular weight of 1000, 11.9 parts by mass of 2,2-dimethylolpropionic acid, and 76.6 parts by mass of isophorone diisocyanate was reacted in the presence of 25.5 parts by mass of methyl ethyl ketone as an organic solvent for 5 hours to obtain an isocyanate group-containing polyurethane (a1-I).

After confirming that 95 to 100% of the hydroxyl groups of the isocyanate group-containing polyurethane (a1-I) were consumed by NCO titration, 55.1 parts by mass of methyl ethyl ketone as a diluting solvent and polyisosoanate (a2) “Coronate HXR” (manufactured by Nippon Polyurethane Industry Co., Ltd .: Nutriate of hexamethylene diisocyanate having an average isocyanate group number of 3.3 to 3.5) is added to 12.1 parts by mass to obtain the isocyanate group-containing polyurethane (a1- An organic solvent solution of I) and the isocyanurate of hexamethylene diisocyanate was obtained.

Next, 8.8 parts by mass of triethylamine is added to the organic solvent solution to neutralize part or all of the carboxyl groups of the polyurethane (a1-I), and further 599.2 parts by mass of water is added. After stirring for 1 minute, 161.0 parts by mass of a 5% by mass diethylenetriamine aqueous solution as polyamine (a3) was added and stirred sufficiently to carry out a crosslinking reaction, whereby aqueous dispersion of composite resin particles (A′-1) was achieved. Got the body.

Next, by aging and removing the aqueous dispersion of the composite resin particles (A′-1), a composite resin having an acid value of 20 and a gel fraction of 85 to 100% by mass and an average particle size of 50 to 500 nm is obtained. An ink-jet printing ink binder having a nonvolatile content of 25% by mass in which the particles (A-1) were dispersed in water was obtained.

[Example 2]
In a nitrogen-substituted container equipped with a thermometer, a nitrogen gas inlet tube, and a stirrer, 141.3 parts by mass of polyoxypropylene glycol having a number average molecular weight of 1000, 11.8 parts by mass of 2,2-dimethylolpropionic acid, and 76.6 parts by mass of isophorone diisocyanate was reacted in the presence of 25.5 parts by mass of methyl ethyl ketone as an organic solvent for 5 hours to obtain an isocyanate group-containing polyurethane (a1-II).

In the isocyanate group-containing polyurethane (a1-II), it was confirmed by NCO titration that 95 to 100% of the hydroxyl groups were consumed, and then 49.9 parts by mass of methyl ethyl ketone as a diluting solvent and polyisosoanate (a2) By adding 17.3 parts by weight of “VESTANAT T1890” (manufactured by EVONIC: isocyanurate of isophorone diisocyanate having an average isocyanate functional group number of 3.1 to 3.5), the isocyanate group-containing polyurethane (a1-II) and An organic solvent solution with the isocyanurate form of isophorone diisocyanate was obtained.

Next, 8.8 parts by mass of triethylamine is added to the organic solvent solution to neutralize part or all of the carboxyl groups of the polyurethane (a1-II), and 598.6 parts by mass of water is added. After stirring for 5 minutes, 165.4 parts by mass of a 5% by mass diethylenetriamine aqueous solution as polyamine (a3) was added, and the mixture was sufficiently agitated to carry out a crosslinking reaction, whereby the composite resin particles (A′-2) were dispersed in water. Got the body.

Subsequently, the aqueous dispersion of the composite resin particles (A′-2) is aged and desolvated to have an acid value of 19.5, a gel fraction of 85% by mass to 100% by mass, and an average particle size of 50 nm to A binder for ink jet printing ink having a nonvolatile content of 25% by mass, in which 500 nm composite resin particles (A-2) were dispersed in water, was obtained.

[Example 3]
In a nitrogen-substituted container equipped with a thermometer, a nitrogen gas introduction tube, and a stirrer, 126.9 parts by mass of polyoxypropylene glycol having a number average molecular weight of 1000, 10.6 parts by mass of 2,2-dimethylolpropionic acid, and 68.8 parts by mass of isophorone diisocyanate was reacted in the presence of 22.9 parts by mass of methyl ethyl ketone as an organic solvent for 5 hours to obtain an isocyanate group-containing polyurethane (a1-III).
In the isocyanate group-containing polyurethane (a1-III), it was confirmed by NCO titration that 95 to 100% of the hydroxyl groups had been consumed. Then, 49.5 parts by mass of methyl ethyl ketone as a diluting solvent and polyisosoanate (a2) By adding 10.9 parts by mass of “Coronate HXR” (manufactured by Nippon Polyurethane Industry Co., Ltd .: hexamethylene diisocyanate nurate having an average number of isocyanate groups of 3.3 to 3.5), the isocyanate group-containing polyurethane (a1-III And an organic solvent solution of the isocyanurate of hexamethylene diisocyanate.
Next, 7.9 parts by mass of triethylamine is added to the organic solvent solution to neutralize part or all of the carboxyl groups of the polyurethane (a1-III), and 537.8 parts by mass of water is added. After stirring for 30 minutes, a cross-linking reaction was carried out by adding 328.2 parts by mass of a 10% by weight polyamine aqueous solution (Jefamine T403 “JEFFAMINE T403”, polyoxypropylene triamine manufactured by HUNTSMAN) as polyamine (a3). To obtain an aqueous dispersion of composite resin particles (A′-3).
Next, by aging and removing the aqueous dispersion of the composite resin particles (A′-3), the acid value is 20, the gel fraction is 85 mass% to 100 mass%, and the average particle diameter is 70 nm to 700 nm. A binder for inkjet printing ink having a non-volatile content of 25% by mass in which the composite resin particles (A-3) were dispersed in water was obtained.

[Example 4]
In a nitrogen-substituted container equipped with a thermometer, a nitrogen gas introduction tube, and a stirrer, 141.4 parts by mass of polyoxytetramethylene glycol having a number average molecular weight of 1000 and 11.9 parts by mass of 2,2-dimethylolpropionic acid And 76.6 parts by mass of isophorone diisocyanate were reacted for 5 hours in the presence of 25.5 parts by mass of methyl ethyl ketone as an organic solvent to obtain an isocyanate group-containing polyurethane (a1-IV).
In the isocyanate group-containing polyurethane (a1-IV), it was confirmed by NCO titration that 95 to 100% of the hydroxyl groups were consumed, and then 55.1 parts by mass of methyl ethyl ketone as a diluting solvent and polyisosoanate (a2) By adding 12.1 parts by mass of “Coronate HXR” (produced by Nippon Polyurethane Industry Co., Ltd .: hexamethylene diisocyanate nurate having an average number of isocyanate groups of 3.3 to 3.5), the isocyanate group-containing polyurethane (a1-IV And an organic solvent solution of the isocyanurate of hexamethylene diisocyanate.
Next, 8.8 parts by mass of triethylamine is added to the organic solvent solution to neutralize part or all of the carboxyl groups of the polyurethane, and further 599.2 parts by mass of water is added, followed by stirring for several minutes. Thereafter, 161.0 parts by mass of a 5% by mass diethylenetriamine aqueous solution was added as polyamine (a3), and the mixture was sufficiently stirred to carry out a crosslinking reaction to obtain an aqueous dispersion of composite resin particles (A′-4).
Next, by aging and removing the aqueous dispersion of the composite resin particles (A′-4), the acid value is 20, the gel fraction is 85% by mass to 100% by mass, and the average particle size is 20 nm to 400 nm. A binder for inkjet printing ink having a nonvolatile content of 25% by mass in which the composite resin particles (A-4) were dispersed in water was obtained.

[Example 5]
In a nitrogen-substituted container equipped with a thermometer, a nitrogen gas inlet tube, and a stirrer, 144.9 parts by mass of polyoxypropylene glycol having a number average molecular weight of 1000, 12.2 parts by mass of 2,2-dimethylolpropionic acid, and 78.5 parts by mass of isophorone diisocyanate was reacted in the presence of 26.2 parts by mass of methyl ethyl ketone as an organic solvent for 5 hours to obtain an isocyanate group-containing polyurethane (a1-V).
In the isocyanate group-containing polyurethane (a1-V), it was confirmed by NCO titration that 95 to 100% of the hydroxyl groups were consumed, and then 56.5 parts by mass of methyl ethyl ketone as a diluting solvent and polyisosoanate (a2) By adding 12.4 parts by mass of “Coronate HXR” (manufactured by Nippon Polyurethane Industry Co., Ltd .: nurate of hexamethylene diisocyanate having an average number of isocyanate groups of 3.3 to 3.5), the isocyanate group-containing polyurethane (a1-V And an organic solvent solution of the isocyanurate of hexamethylene diisocyanate.
Next, 9.0 parts by mass of triethylamine is added to the organic solvent solution to neutralize part or all of the carboxyl groups of the polyurethane (a1-V), and 614.0 parts by mass of water is further added. After stirring for 4 minutes, 41.2 parts by mass of a 5% by mass diethylenetriamine aqueous solution as polyamine (a3) was added and sufficiently stirred to carry out a crosslinking reaction, whereby an aqueous dispersion of composite resin particles (A′-5) was obtained. Obtained.
Next, by aging and removing the aqueous dispersion of the composite resin particles (A′-5), the acid value is 20, the gel fraction is 40 mass% to 70 mass%, and the average particle diameter is 50 nm to 500 nm. A binder for inkjet printing ink having a non-volatile content of 25% by mass in which the composite resin particles (A-5) were dispersed in water was obtained.

[Comparative Example 1]
In a nitrogen-substituted container equipped with a thermometer, a nitrogen gas introduction tube, and a stirrer, 162.8 parts by mass of polyoxypropylene glycol having a number average molecular weight of 1000, 13.7 parts by mass of 2,2-dimethylolpropionic acid, and 70.6 parts by mass of isophorone diisocyanate was reacted in the presence of 27.5 parts by mass of methyl ethyl ketone as an organic solvent for 5 hours to obtain an isocyanate group-containing polyurethane (x ′).
In the isocyanate group-containing polyurethane (x ′), it was confirmed by NCO titration that 95 to 100% of the hydroxyl groups were consumed. Then, 105.6 parts by mass of methyl ethyl ketone was added as a diluting solvent, and then triethylamine was added by 10.1. By adding part by mass, a part or all of the carboxyl group of the polyurethane is neutralized, and after adding 732.9 parts by mass of water and stirring for several minutes, 5 mass% diethylenetriamine aqueous solution 58. An aqueous dispersion of composite resin particles (x ′) was obtained by carrying out a crosslinking reaction by adding 2 parts by mass and stirring sufficiently.
Next, by aging and removing the water dispersion, the composite resin particles (x) having an acid value of 20 and a gel fraction of 40% by mass to 70% by mass and an average particle size of 50 nm to 500 nm are dissolved in water. A binder for ink jet printing ink having a dispersed nonvolatile content of 25% by mass was obtained.

[Comparative Example 2]
In a nitrogen-substituted container equipped with a thermometer, a nitrogen gas introduction tube, and a stirrer, 173.0 parts by mass of polyoxypropylene glycol having a number average molecular weight of 1000, 14.5 parts by mass of 2,2-dimethylolpropionic acid, and 62.5 parts by mass of isophorone diisocyanate was reacted in the presence of 83.3 parts by mass of methyl ethyl ketone as an organic solvent for 8 hours.
When the weight average molecular weight of the reactant has reached the range of 20000 to 50000, the reaction is terminated by adding 1.8 parts by mass of methanol, and further, 164.9 parts by mass of methyl ethyl ketone is added as a diluent solvent, 500.0 parts by mass of an organic solvent solution of polyurethane having an acid value of 24 (nonvolatile content: 50% by mass) was obtained.
Next, 10.8 parts by mass of triethylamine is added to the polyurethane organic solvent solution to neutralize part or all of the carboxyl groups of the polyurethane, and further 739.2 parts by mass of water is added and stirred sufficiently. As a result, an aqueous dispersion of polyurethane (y ′) was obtained.
Subsequently, the polyurethane (y) having an acid value of 24, a gel fraction of 1% by mass to 30% by mass and an average particle size of 10 nm to 100 nm is obtained by aging and removing the aqueous dispersion of the polyurethane (y ′). A binder for inkjet printing ink having a nonvolatile content of 25% by mass dispersed in water was obtained.

[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 aqueous potassium hydroxide solution Was loaded 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.

The ion-exchanged water heated to 60 ° C. with a total amount of 8000 g was added to the kneaded material 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 min, 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 Example 1 to 5 and Comparative Examples 1 and 2, the ink-jet printing ink binders and Preparation Example 1 were prepared so that the concentration of the quinacridone pigment was 4% by mass and the concentration of polyurethane was 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 ink jet printing ink obtained in Examples 1 to 5 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 ink jet 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.

The 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 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 and the state of the nozzle was confirmed with a Photomart D5360 (manufactured by Hewlett-Packard Company) in which a black ink cartridge was filled with the inkjet pigment ink.
Subsequently, after 40 pages of solid printing with a printing density setting of 100% in an area of 18 cm × 25 cm per page were continuously performed, 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 Insufficient ink ejection direction or non-ejection of ink after 40 pages of continuous printing ×: Abnormal ink ejection direction or non-ejection of ink occurred during printing. What could not be completed solid printing

[Printing performance evaluation of pigment 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 pigment ink is applied to a black ink cartridge. An evaluation printed matter was obtained by filling and performing solid printing with a print density setting of 100%.

After the printed matter for evaluation was dried at room temperature for 10 minutes, the printed surface was scratched with a nail under a load of about 5 kg, and the rubbing condition of the color of the printed surface was visually evaluated according to the following evaluation criteria. In addition, since the ejection stability of 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 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 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.

“Molar ratio 1” in Tables 1 and 2 indicates that the isocyanate group [X1] of the isocyanate group-containing polyurethane (a1) constituting the composite resin particle (A) and the isocyanate group [X2] of the polyisocyanate (a2). ] And the molar ratio [isocyanate group [X1] / isocyanate group [X2]].
The “molar ratio 2” in Tables 1 and 2 is the molar ratio of the amino group [Y] and the total of the isocyanate group [X1] and the isocyanate group [X2] [amino group [Y] / {isocyanate. Group [X1] and isocyanate group [X2] total}].

Claims

The composite resin particles (A) formed by the reaction of the isocyanate group-containing polyurethane (a1), the polyisocyanate (a2) other than the isocyanate group-containing polyurethane (a1), and the polyamine (a3) are formed in the aqueous medium (B). A binder for ink-jet printing inks, characterized by being dispersed.
In the composite resin particle (A), the isocyanate group [X1] of the isocyanate group-containing polyurethane (a1) and the isocyanate group [X2] of the polyisocyanate (a2) are an amino group of the polyamine (a3). The binder for inkjet printing inks of Claim 1 which each reacts with group [Y] and forms the bond.
The molar ratio of the isocyanate group [X1] of the isocyanate group-containing polyurethane (a1) constituting the composite resin particle (A) to the isocyanate group [X2] of the polyisocyanate (a2) is [isocyanate group [X1] / Isocyanate group [X2]] = 0.1-20, and the molar ratio of amino group [Y] to the total of isocyanate group [X1] and isocyanate group [X2] is [amino group [Y The binder for ink-jet printing ink according to claim 2, wherein the sum of isocyanate group [X1] and isocyanate group [X2]} = 0.3-3.
In the resin particles (a) formed by the isocyanate group-containing polyurethane (a1), the composite resin particles (A) contain a part or all of the polyisocyanate (a2) and the polyamine (a3), The binder for inkjet printing inks of Claim 1 which is a thing which carried out the crosslinking reaction in the resin particle (a).
The binder for ink jet printing ink according to claim 1, wherein the composite resin particles (A) have an acid value of 1 mgKOH / g to 70 mgKOH / g.
The binder for ink jet printing ink 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 binder for inkjet printing ink according to claim 1, wherein the polyisocyanate (a2) has a number average molecular weight of 300 to 5,000.
The binder for ink jet printing ink according to claim 1, wherein the polyisocyanate (a2) has 2 to 6 isocyanate groups.
The binder for inkjet printing inks of Claim 1 whose all amino groups which the said polyamine (a3) has are a primary amino group or a secondary amino group.
Producing a dispersion in which composite resin particles (A ′) containing an isocyanate group-containing polyurethane (a1) and a polyisocyanate (a2) other than the isocyanate group-containing polyurethane (a1) are dispersed in an aqueous medium (B); By mixing the dispersion and the polyamine (a3), the reaction of the isocyanate group-containing polyurethane (a1), the polyisocyanate (a2), and the polyamine (a3) in the composite resin particles (A ′) is performed. Inkjet printing in which composite resin particles (A) formed by reaction of isocyanate group-containing polyurethane (a1), polyisocyanate (a2) and polyamine (a3) are dispersed in aqueous medium (B), A method for producing a binder for ink.
An ink for inkjet printing comprising the binder for inkjet printing ink according to any one of claims 1 to 9, and a pigment or a dye.
A printed matter printed with the ink jet printing ink according to claim 11.