JP6339930B2 - Water-based ink for inkjet recording - Google Patents

Description

  The present invention relates to an aqueous ink for inkjet recording, a method for producing the same, and an inkjet recording method.

The ink jet recording method is a recording method in which characters and images are obtained by ejecting ink droplets directly from a very fine nozzle and attaching them to a recording member. This method is very popular because it is easy to achieve full color and is inexpensive, has a number of advantages such as the ability to use plain paper as a recording member and non-contact with the substrate.
In addition, recordings made of resin such as PET (polyethylene terephthalate), PP (polypropylene), PVC (polyvinyl chloride), which have been conventionally printed with solvent-based inks, UV curable inks, etc. for reasons such as environmental impact and safety. The use of an ink jet recording system using water-based ink is also demanded for the medium.

Patent Document 1 discloses a water-based ink containing a suspension of a polyester adsorbed with a dye or pigment as a water-based ink having improved fixing properties and water resistance to a printed material such as paper or an OHP sheet.
Patent Document 2 discloses a water-based ink that has good bleeding, water resistance, print density, and scratch resistance of a printed matter, and that has improved scoring at the head when used in a thermal jet ink jet printer. Including a polyester emulsion adsorbed with an insoluble or poorly water-soluble coloring material, the polyester contains a specific diol component, trimellitic anhydride, and a polyvalent carboxylic acid other than trimellitic anhydride and / or a derivative thereof. An aqueous ink that is obtained by condensation polymerization is disclosed.
Patent Document 3 includes a polyurethane resin and a cellulose resin as essential components as a printing ink composition having excellent adhesion to substrates such as polypropylene, polyester, and nylon, and having excellent oil resistance, heat resistance, and blocking resistance. In the printing ink composition, the polyurethane resin is obtained by extending a chain of a urethane prepolymer obtained by reacting a polyol component and an organic diisocyanate with a diamine compound, and terminating at least one of a long-chain alkyl group and an alkenyl group. There is disclosed a printing ink composition which is a polyurethane resin which has been reacted with an aliphatic amine compound and / or an aliphatic amide compound having at least one of a long-chain alkyl group and an alkenyl group.
Patent Document 4 discloses an ink jet recording ink having no nozzle clogging, excellent print quality, no show-through, excellent storage stability, and excellent water resistance and erase rubber resistance of the obtained printed matter. Ink jet recording inks containing pigments, fine particles of a polyester resin having a particle size of 30 to 300 nm, and water-soluble epoxy compounds are disclosed.

JP-A-9-183932 JP 2000-7963 A Japanese Patent Laid-Open No. 2004-204048 JP 2003-313468 A

However, since resin recording media such as PET and PVC are non-water-absorbing media, water-based ink does not easily permeate, the fixability is low, and the ink spread on the film is poor, so that an ink film is formed. As a result, the smoothness was poor and the abrasion resistance was insufficient.
In addition, PVC films frequently used in sign graphics such as vehicle wrapping are also required to have abrasion resistance and alcohol resistance that can be adapted for outdoor use and cleaning. Conventional inks such as ink have not reached a technical level that satisfies all these characteristics.
Accordingly, an object of the present invention relates to providing a water-based ink for ink jet recording which is particularly excellent in adhesion and rubbing resistance to a resin recording medium having a polarity such as PVC and at the same time excellent in alcohol resistance.

In order to solve the above-mentioned problems with water-based inks, the present inventors have stable the ink components having high adhesion to the resin recording medium after printing the ink on the surface of the resin recording medium. We considered it important to form a protective film. As a result, an alcohol component containing an aliphatic diol having 3 to 6 carbon atoms and having a hydroxy group bonded to a secondary carbon atom, and 2 to 12 mol% of a trivalent or higher polyvalent carboxylic acid is contained. By including resin particles containing polyester obtained by polycondensation of the carboxylic acid component in the water-based ink, adhesion to a resin recording medium having a polarity such as PVC and abrasion resistance, and at the same time, alcohol resistance are achieved. It was found that it can be improved.
That is, the present invention relates to the following [1] to [3].
[1] A water-based ink for inkjet recording containing a colorant and polyester resin particles (A), wherein the polyester constituting the polyester resin particles (A) has a hydroxy group bonded to a secondary carbon atom. An alcohol component containing 45 to 100 mol% of an aliphatic diol of 3 or more and 6 or less and a carboxylic acid component containing 2 to 12 mol% of a trivalent or higher polyvalent carboxylic acid; A water-based ink for ink-jet recording, which is a polyester obtained in this way.
[2] The method for producing a water-based ink for inkjet recording according to [1], comprising the following steps (1) to (3).
Step (1): an alcohol component containing 45 to 100 mol% of an aliphatic diol having 3 to 6 carbon atoms and having a hydroxy group bonded to a secondary carbon atom, and a trivalent or higher polyvalent carboxylic acid Step of obtaining a polyester by polycondensation of a carboxylic acid component containing 2 mol% or more and 12 mol% or less of step (2): The polyester obtained in step (1) is mixed with an aqueous medium to obtain polyester resin particles ( A) Step for obtaining an aqueous dispersion Step (3): Mixing the aqueous dispersion of the polyester resin particles (A) obtained in Step (2) with an aqueous dispersion containing a colorant, and water for inkjet recording Step 3 of obtaining a system ink After the water-based ink described in [1] is attached to a resin recording medium by an ink jet recording method, the resin recording medium is heated to 40 ° C. or more and 100 ° C. or less. That, the ink-jet recording method.

  ADVANTAGE OF THE INVENTION According to this invention, the water-based ink for inkjet recordings which is excellent in the adhesiveness and abrasion resistance to the resin-made recording media which have polarity, such as PVC, is excellent also in alcohol resistance simultaneously.

[Water-based ink for inkjet recording]
The water-based ink for ink-jet recording according to the first embodiment of the present invention is a water-based ink for ink-jet recording containing a colorant and polyester resin particles (A), and the polyester constituting the polyester resin particles (A) is: An alcohol component containing 45 to 100 mol% of an aliphatic diol having 3 to 6 carbon atoms and having a hydroxy group bonded to a secondary carbon atom, and 2 mol% or more of a trivalent or higher polyvalent carboxylic acid It is a water-based ink for inkjet recording, which is a polyester obtained by polycondensation of a carboxylic acid component containing 12 mol% or less.
In the present specification, “water-based ink for inkjet recording” is also simply referred to as “water-based ink”.

By using the water-based ink for ink-jet recording, it is possible to provide a water-based ink for ink-jet recording which is excellent in adhesion and abrasion resistance to a resin recording medium having a polarity such as PVC and at the same time excellent in alcohol resistance. The reason why the water-based ink has such an effect is not clear, but is considered as follows.
The water-based ink contains a colorant and polyester resin particles (A). When the water-based ink lands on the recording medium during printing, the polyester constituting the polyester resin particles (A) diffuses onto the printing surface of the recording medium on the film and acts as a fixing aid for the colorant. Here, the polyester constituting the polyester resin particles (A) is an alcohol component containing 45 mol% or more and 100 mol% or less of an aliphatic diol having 3 to 6 carbon atoms having a hydroxy group bonded to a secondary carbon atom. And a polyester obtained by polycondensation of a carboxylic acid component containing 2 mol% or more and 12 mol% or less of a trivalent or higher polyvalent carboxylic acid. By using an alcohol component containing 45 mol% or more and 100 mol% or less of an aliphatic diol having 3 to 6 carbon atoms having a hydroxy group bonded to a secondary carbon atom as a polyester raw material monomer, a unit in the polyester molecule Since the amount of ester groups per length increases and interacts strongly with polar groups of resin recording media having a polarity such as PVC, it is considered that the adhesion is improved.
Furthermore, by using a specific amount of a trivalent or higher polyvalent carboxylic acid, the molecular weight of the polyester can be increased while appropriately crosslinking the polyester. As a result, it is possible to form a flexible film on the printed surface because the degree of crosslinking is not high, and the abrasion resistance is improved. It is considered that alcohol resistance is improved because the penetration and swelling of alcohol in the film is suppressed.
Hereinafter, each component and each process used for the aqueous ink for inkjet recording of the present invention will be described.

<Polyester resin particles (A)>
The resin constituting the polyester resin particles (A) contains a specific polyester from the viewpoint of improving adhesion to a resin recording medium such as PVC, rubbing resistance, and alcohol resistance. The polyester content in the polyester resin particles (A) is preferably 90% by mass or more, more preferably 95% by mass or more, still more preferably 98% by mass or more, and still more preferably 100% by mass. As long as the effect of the present invention is not impaired, a resin other than the polyester may be a known resin used for water-based ink for ink jet recording, such as styrene-acrylic copolymer, epoxy, polycarbonate, polyurethane, and the like. .

(polyester)
The polyester constituting the polyester resin particles (A) comprises an alcohol component containing 45 to 100 mol% of an aliphatic diol having 3 to 6 carbon atoms and having a hydroxy group bonded to a secondary carbon atom; It is obtained by polycondensation of a carboxylic acid component containing 2 mol% or more and 12 mol% or less of a polyvalent carboxylic acid having a valency or higher.
The polyester preferably has an acid group at the end of the molecular chain from the viewpoint of improving the dispersion stability of the dispersion of the polyester resin particles (A) described later. Examples of the acid group include a carboxy group, a sulfonic acid group, a phosphonic acid group, and a sulfinic acid group. Among these, a carboxy group is preferable from the viewpoint of improving the dispersion stability of the dispersion of the polyester resin particles (A).

[Alcohol component]
The alcohol component, which is a raw material monomer of the polyester used in the present invention, is bonded to a secondary carbon atom from the viewpoint of obtaining a water-based ink excellent in adhesion to a resin recording medium such as PVC, abrasion resistance and alcohol resistance. The aliphatic diol having 3 to 6 carbon atoms having a hydroxy group is contained in an amount of 45 mol% to 100 mol%.
Examples of the aliphatic diol having 3 to 6 carbon atoms and having a hydroxy group bonded to a secondary carbon atom include 1,2-propanediol, 1,2-butanediol, 1,3-butanediol, 2,3- Butanediol, 1,2-pentanediol, 1,4-pentanediol, 2,4-pentanediol, 1,2-hexanediol, 1,5-hexanediol, 2,5-hexanediol, 3,3-dimethyl -1,2-butanediol and the like, and one or more of these are used. From the viewpoint of obtaining a water-based ink excellent in adhesion to a resin recording medium, scratch resistance and alcohol resistance, the aliphatic diol having a hydroxy group bonded to a secondary carbon atom preferably has 3 or 4 carbon atoms. 1,2-propanediol and 2,3-butanediol are more preferable, and 1,2-propanediol is more preferable.
The content of the aliphatic diol having 3 to 6 carbon atoms and having a hydroxy group bonded to a secondary carbon atom in the alcohol component which is a raw material monomer for polyester is 45 mol% or more and 100 mol% or less. When the content is 45 mol% or more, the adhesion of the water-based ink to a resin recording medium such as PVC is improved. From the same viewpoint, it is preferably 60 mol% or more, more preferably 70 mol% or more, still more preferably 75 mol% or more. From the viewpoint of obtaining a water-based ink excellent in abrasion resistance and alcohol resistance, it is preferably 95 mol% or less, more preferably 90 mol% or less, and still more preferably 85 mol% or less.

  The alcohol component, which is a raw material monomer for polyester, can contain the following alcohol components in addition to the aliphatic diol having 3 to 6 carbon atoms and having a hydroxy group bonded to a secondary carbon atom. For example, ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol, glycerin, pentaerythritol, trimethylolpropane, alkylene oxide adduct of bisphenol A, hydrogenated bisphenol A, sorbitol, Or the alkylene (C2-C4) oxide adduct (average addition mole number 1-16) etc. are mentioned, You may use individually or in combination of 2 or more types.

[Carboxylic acid component]
The carboxylic acid component, which is a raw material monomer of the polyester used in the present invention, contains a trivalent or higher polyvalent carboxylic acid in an amount of 2 mol% to 12 mol%.
When the content of the carboxylic acid is 2 mol% or more, the alcohol resistance is improved because the penetration and swelling of the alcohol in the polyester film that protects the printing surface is suppressed by having a certain degree of crosslinking. Further, if the content of the carboxylic acid is 12 mol% or less, the degree of crosslinking is not high, so that a flexible film can be formed on the printing surface, and the abrasion resistance is improved.
From the same viewpoint, the content of the trivalent or higher polyvalent carboxylic acid in the carboxylic acid component is preferably 3 mol% or more, more preferably 4 mol% or more, and preferably 10 mol% or less, more Preferably it is 8 mol% or less, More preferably, it is 6 mol% or less.
In addition, when using 2 or more types of polyester mixed, content of this trivalent or more polyvalent carboxylic acid is trivalence or more in the total amount of the carboxylic acid component which is a raw material monomer of 2 or more types of polyester. The total content of polyvalent carboxylic acids. In addition, in the use of carboxylic acids, those acid anhydrides and alkyl esters having 1 to 3 carbon atoms may be used. In the present invention, “an alkyl ester having 1 to 3 carbon atoms of an acid” means “an ester in which an alkyl group having 1 to 3 carbon atoms is bonded to an acid”.

  Specific examples of the trivalent or higher polyvalent carboxylic acid compound include 1,2,4-benzenetricarboxylic acid (trimellitic acid), 2,5,7-naphthalenetricarboxylic acid, 1,2,4,5-benzenetetra Examples thereof include carboxylic acids (pyromellitic acid), acid anhydrides thereof, and alkyl esters having 1 to 3 carbon atoms, and may be used alone or in combination of two or more. From the viewpoint of obtaining a water-based ink excellent in adhesion to a resin recording medium such as PVC, rubbing resistance and alcohol resistance, 1,2,4-benzenetricarboxylic acid (trimellitic acid) and its acid anhydride are preferable.

The carboxylic acid component, which is a raw material monomer for polyester, can contain a carboxylic acid other than a trivalent or higher polyvalent carboxylic acid. Carboxylic acids other than trivalent or higher polyvalent carboxylic acids are not particularly limited, and include aromatic dicarboxylic acids, aliphatic dicarboxylic acids, and alicyclic dicarboxylic acids.
Examples of the aliphatic dicarboxylic acid include sebacic acid, fumaric acid, maleic acid, adipic acid, azelaic acid, succinic acid, an alkyl group having 1 to 20 carbon atoms, or a succinic acid substituted with an alkenyl group having 2 to 20 carbon atoms. Etc. Specific examples of the succinic acid substituted with an alkyl group having 1 to 20 carbon atoms or an alkenyl group having 2 to 20 carbon atoms include dodecyl succinic acid, dodecenyl succinic acid, octenyl succinic acid, and the like.
Specific examples of the aromatic dicarboxylic acid include phthalic acid, isophthalic acid, terephthalic acid and the like. Among these, terephthalic acid is preferable.
Specific examples of the alicyclic dicarboxylic acid include cyclohexane dicarboxylic acid.
Carboxylic acids other than trivalent or higher polyvalent carboxylic acids may be used alone or in combination of two or more.
The content of the carboxylic acid other than the trivalent or higher polyvalent carboxylic acid in the carboxylic acid component is preferably 88 mol from the viewpoint of obtaining a water-based ink excellent in adhesion to a resin recording medium such as PVC and abrasion resistance. % Or more, more preferably 90 mol% or more, still more preferably 92 mol% or more, still more preferably 94 mol% or more, and an aqueous system excellent in adhesion to a resin recording medium such as PVC and alcohol resistance From the viewpoint of obtaining ink, it is preferably 98 mol% or less, more preferably 97 mol% or less, and still more preferably 96 mol% or less.
In addition, when using 2 or more types of polyesters in mixture, content of carboxylic acid other than this trivalent or more polyvalent carboxylic acid is in the total amount of the carboxylic acid component which is a raw material monomer of 2 or more types of polyesters. It means the total content of carboxylic acids other than trivalent or higher polyvalent carboxylic acids.
Further, a molar ratio of a trivalent or higher polyvalent carboxylic acid to a carboxylic acid other than a trivalent or higher polyvalent carboxylic acid (a trivalent or higher polyvalent carboxylic acid / a carboxylic acid other than a trivalent or higher polyvalent carboxylic acid). Is preferably 88/12 or more, preferably 90/10 or more, more preferably 92/8 or more, and still more preferably, from the viewpoint of obtaining a water-based ink excellent in adhesion to a resin recording medium such as PVC and abrasion resistance. Is 94/6 or more, and is preferably 98/2 or less, more preferably 97/3 or less, and more preferably 97/3 or less from the viewpoint of obtaining a water-based ink having excellent adhesion to a resin recording medium such as PVC and alcohol resistance. Preferably it is 96/4 or less.

  From the viewpoint of obtaining a water-based ink excellent in adhesion to a recording medium made of resin such as PVC, rubbing resistance and alcohol resistance, the molar ratio of the carboxyl group of the carboxylic acid component to the hydroxyl group of the alcohol component (carboxy group / hydroxyl group). Preferably it is 0.75 or more, more preferably 0.80 or more, and preferably 1.20 or less, more preferably 1.10 or less, and still more preferably 1.00 or less.

  The softening point of the polyester used in the present invention is preferably 100 ° C. or higher, more preferably 120 ° C., from the viewpoint of obtaining a water-based ink excellent in adhesion to resin recording media such as PVC, rubbing resistance and alcohol resistance. More preferably, it is 130 ° C. or higher, and preferably 165 ° C. or lower, more preferably 160 ° C. or lower, and still more preferably 150 ° C. or lower. In addition, this softening point can be measured by the method as described in an Example.

  The glass transition temperature of the polyester used in the present invention is preferably 40 ° C. or higher, more preferably 50 from the viewpoint of obtaining a water-based ink excellent in adhesion to a resin recording medium such as PVC, abrasion resistance and alcohol resistance. More preferably, it is not less than 53 ° C, more preferably not more than 80 ° C, more preferably not more than 75 ° C, and still more preferably not more than 70 ° C. In addition, this glass transition temperature can be measured by the method as described in an Example.

The weight average molecular weight of the polyester used in the present invention is preferably 10,000 or more, more preferably from the viewpoint of obtaining a water-based ink having excellent adhesion to a resin recording medium such as PVC, abrasion resistance and alcohol resistance. 20,000 or more, more preferably 30,000 or more, and preferably 500,000 or less, more preferably 200,000 or less, still more preferably 100,000 or less, and even more preferably 80,000 or less. It is.
From the same viewpoint, the number average molecular weight of the polyester used in the present invention is preferably 1,000 or more, more preferably 2,000 or more, still more preferably 3,000 or more, and still more preferably 4,000 or more. And preferably 50,000 or less, more preferably 20,000 or less, still more preferably 10,000 or less, and even more preferably 7,000 or less.
The weight average molecular weight and number average molecular weight of the polyester can be measured by the methods described in the Examples.

  The acid value of the polyester used in the present invention is preferably 5 mgKOH / g or more, more preferably 10 mgKOH / g or more, still more preferably from the viewpoint of improving the dispersion stability of the dispersion of the polyester resin particles (A) described later. 15 mgKOH / g or more, and preferably 30 mgKOH / g or less, more preferably 25 mgKOH / g or less, and further preferably 20 mgKOH / g or less. In addition, the acid value of this polyester can be measured by the method as described in an Example.

The ester group concentration of the polyester used in the present invention is preferably 6.0 mmol / g or more, more preferably 7.0 mmol / g or more, from the viewpoint of obtaining a water-based ink excellent in adhesion to a resin recording medium such as PVC. More preferably, it is 7.5 mmol / g or more, More preferably, it is 8.0 mmol / g or more, More preferably, it is 8.5 mmol / g or more. Moreover, from a viewpoint of ensuring the water resistance of printed matter, it is preferably 12.0 mmol / g or less, more preferably 10.0 mmol / g or less.
The ester group concentration of the polyester can be determined by the method described in the examples.
The softening point, glass transition temperature, weight average molecular weight, number average molecular weight, acid value and ester group concentration of the polyester are all appropriately determined depending on the type of monomer used in the production of the polyester, the blending ratio, the polycondensation temperature and the reaction time. The desired product can be obtained by adjusting.

  In addition, the polyester used in the present invention is not only unmodified polyester but also substantially its characteristics as long as it has a polycondensation of the alcohol component and the carboxylic acid component and has an acid group. Also included are polyesters modified to such an extent that they are not impaired. As a modification method, for example, grafting or blocking with phenol, urethane, epoxy, or the like by the method described in JP-A-11-133668, JP-A-10-239903, JP-A-8-20636, etc. A method is mentioned. Moreover, the composite resin which has 2 or more types of resin units containing the polyester unit used for this invention is mentioned.

The polyester used in the present invention can be produced by polycondensing the alcohol component and the carboxylic acid component in an inert gas atmosphere using an esterification catalyst as necessary.
The temperature of the polycondensation reaction is preferably 160 ° C. or higher, more preferably 170 ° C. or higher, further preferably 180 ° C. or higher, and preferably 260 ° C. or lower, more preferably 240 ° C., from the viewpoint of reactivity. It is as follows.

Examples of esterification catalysts include esterification catalysts such as tin compounds such as dibutyltin oxide and di (2-ethylhexanoic acid) tin, and titanium compounds such as titanium diisopropylate bistriethanolamate, and acids such as paratoluenesulfonic acid. A catalyst can be used individually or in mixture of 2 or more types. From the viewpoint of reaction efficiency, di (2-ethylhexanoic acid) tin is preferable, and from the viewpoint of molecular weight control, it is preferable to use an esterification catalyst and an acid catalyst in combination.
The amount of the esterification catalyst used is, for example, preferably 0.01 parts by mass or more, more preferably 0.1 parts by mass or more, and still more preferably 0.1 parts by mass with respect to 100 parts by mass of the total amount of the alcohol component and the carboxylic acid component. 3 parts by mass or more, and preferably 1.5 parts by mass or less, more preferably 1.0 parts by mass or less, and still more preferably 0.8 parts by mass or less.

  Moreover, a polymerization inhibitor can be used as needed. Examples of the polymerization inhibitor include 4-tert-butylcatechol. The amount of the polymerization inhibitor used is preferably 0.001 part by mass or more, more preferably 0.005 part by mass or more, and preferably 0 with respect to 100 parts by mass of the total amount of the alcohol component and the carboxylic acid component. 0.5 parts by mass or less, more preferably 0.1 parts by mass or less.

(Method for producing polyester resin particles (A))
The polyester resin particles (A) are preferably produced by a method in which the above-mentioned polyester-containing resin is dispersed in an aqueous medium to obtain a dispersion of the polyester resin particles (A).
As the aqueous medium, those containing water as a main component are preferable. From the viewpoint of improving the dispersion stability of the resin particle dispersion and from the viewpoint of environmental safety, the content of water in the aqueous medium is preferably 80% by mass. As mentioned above, More preferably, it is 90 mass% or more, More preferably, it is 100 mass%. As water, deionized water or distilled water is preferably used. Examples of components other than water include alcohol solvents such as methanol, ethanol, isopropanol, and butanol; ketone solvents such as acetone and methyl ethyl ketone; and organic solvents that dissolve in water such as ether solvents such as tetrahydrofuran.

  As a method of obtaining a dispersion of polyester resin particles (A), a method of adding a polyester-containing resin to an aqueous medium and performing a dispersion treatment with a disperser, etc., and gradually adding an aqueous medium to a polyester-containing resin From the viewpoint of obtaining a water-based ink excellent in adhesion to a resin recording medium having a polarity such as PET and PVC and glossiness, a method by phase inversion emulsification is preferable. As the phase inversion emulsification method, it is preferable to first dissolve a polyester-containing resin in an organic solvent, then add an aqueous medium to the solution to perform phase inversion, and then remove the organic solvent. Hereinafter, the phase inversion emulsification method will be described.

[Transfer emulsification method]
First, a resin containing polyester is dissolved in an organic solvent to obtain a solution containing polyester.
In the case of including a plurality of types of polyesters or resins other than polyester, a mixture of these polyesters and other resins may be used in advance, but these resins are simultaneously added to an organic solvent and dissolved to obtain a polyester. You may obtain the solution containing.
In addition, it is possible to improve the affinity of the resin containing the polyester to the aqueous medium, to improve the dispersion stability of the resin particle dispersion, and to adhere to a resin recording medium such as PVC, and the abrasion resistance and resistance. From the viewpoint of obtaining a water-based ink excellent in alcoholic properties, it is preferable to use a basic aqueous solution.
As a method for obtaining a solution containing polyester, a method in which a polyester-containing resin and an organic solvent are placed in a container and dissolved, then a basic aqueous solution is placed in the container and stirred with a stirrer to obtain a solution is preferable.
The operation of dissolving the polyester-containing resin in the organic solvent and the subsequent addition of the basic aqueous solution are usually performed at a temperature not higher than the boiling point of the organic solvent.
The organic solvent is preferably a dialkyl ketone having an alkyl group having 1 to 3 carbon atoms, such as acetone and methyl ethyl ketone, from the viewpoint of dissolving a polyester-containing resin and easy removal from the emulsion. Methyl ethyl ketone.

  From the viewpoint of improving the dispersion stability of the resin particle dispersion, the mass ratio of the organic solvent and the resin containing the polyester [organic solvent / resin] is from the viewpoint of dissolving the resin and facilitating phase inversion to an aqueous medium. Preferably it is 30/100 or more, more preferably 50/100 or more, still more preferably 70/100 or more, and preferably 500/100 or less, more preferably 300/100 or less, still more preferably 200/100 or less, More preferably, it is 150/100 or less.

Examples of the basic compound used in the basic aqueous solution include inorganic basic compounds and organic basic compounds.
Examples of the inorganic base compound include hydroxides, carbonates and hydrogen carbonates of alkali metals such as potassium, sodium and lithium. Specific examples thereof include sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate and hydrogen carbonate. Examples include sodium and potassium bicarbonate. Ammonia may also be used. Examples of the organic base include alkanolamines such as diethylethanolamine. From the viewpoint of improving the dispersion stability of the resin particle dispersion, and from the viewpoint of obtaining a water-based ink excellent in adhesion to a resin recording medium such as PVC, rubbing resistance and alcohol resistance, sodium hydroxide, potassium hydroxide Sodium carbonate and potassium carbonate are preferable, and sodium hydroxide is more preferable.
The concentration of the basic compound in the basic aqueous solution is preferably 1% by mass or more, more preferably 3% by mass or more, and preferably from the viewpoint of improving the dispersion stability and productivity of the resin particle dispersion. It is 60 mass% or less, More preferably, it is 50 mass% or less.

Next, an aqueous medium is added to the polyester-containing solution to perform phase inversion to obtain an aqueous dispersion of the resin particles (A) containing the polyester.
From the viewpoint of improving the dispersion stability of the resin particle dispersion, the temperature at which the aqueous medium is added is preferably 10 ° C or higher, more preferably 20 ° C or higher, still more preferably 25 ° C or higher, and preferably 80 ° C. or lower, more preferably 75 ° C. or lower.

From the viewpoint of improving the dispersion stability of the resin particle dispersion, and from the viewpoint of obtaining an aqueous ink having excellent adhesion to a resin recording medium such as PVC, abrasion resistance, and alcohol resistance. Until the phase inversion is completed, the amount is preferably 0.5 parts by mass / min, more preferably 1 part by mass / min, and further preferably 3 parts by mass / min with respect to 100 parts by mass of the resin constituting the resin particles. Or more, more preferably 5 parts by mass or more, and preferably 100 parts by mass or less, more preferably 50 parts by mass or less, still more preferably 20 parts by mass or less, and still more preferably. 15 parts by mass / min or less. There is no restriction | limiting in the addition speed | rate of the aqueous medium after the resin phase is obtained after phase inversion.
The addition amount of the aqueous medium is preferably 50 parts by mass or more, more preferably 100 parts by mass or more, and still more preferably from 100 parts by mass of the resin constituting the resin particles, from the viewpoint of improving the productivity of the aqueous dispersion. 150 parts by mass or more, and preferably 900 parts by mass or less, more preferably 500 parts by mass or less, and still more preferably 400 parts by mass or less.

After phase inversion emulsification, the organic solvent may be removed from the dispersion obtained by phase inversion emulsification, if necessary.
The method for removing the organic solvent is not particularly limited, and any method can be used. However, since it is dissolved in water, it is preferably distilled.
The aqueous dispersion of the polyester resin particles (A) thus obtained is preferably filtered through a wire mesh or the like to remove coarse particles and the like. In addition, when the organic solvent is removed, water is azeotropically reduced with the organic solvent, so it is preferable to adjust the solid concentration by adding water.
The solid content concentration after the adjustment is preferably 5% by mass or more, more preferably 10% by mass or more from the viewpoint of obtaining a water-based ink excellent in adhesion to a resin recording medium such as PVC, rubbing resistance and alcohol resistance. More preferably, it is 20% by mass or more, more preferably 25% by mass or more, and preferably 50% by mass or less, more preferably 45% by mass or less, still more preferably 40% by mass or less, and still more preferably 35%. It is below mass%.

  The pH of the aqueous dispersion of the obtained polyester resin particles (A) is preferably 6 or more from the viewpoint of obtaining a water-based ink having excellent adhesion to a resin recording medium such as PVC, abrasion resistance and alcohol resistance. More preferably, it is 6.5 or more, More preferably, it is 7.0 or more, More preferably, it is 7.5 or more, Preferably it is 9.0 or less, More preferably, it is 8.5 or less, More preferably, it is 8.2. It is as follows.

The volume average particle diameter of the polyester resin particles (A) is preferably 50 nm or more from the viewpoint of obtaining a water-based ink that is excellent in dischargeability and excellent in adhesion to resin recording media such as PVC, abrasion resistance, and alcohol resistance. More preferably 70 nm or more, still more preferably 90 nm or more, and preferably 200 nm or less, more preferably 150 nm or less, still more preferably 100 nm or less.
The volume average particle diameter of the polyester resin particles (A) is measured by a dynamic light scattering method, and specifically measured by the method of the example.

<Colorant>
As the colorant used in the present invention, for example, pigments, hydrophobic dyes, water-soluble dyes (acid dyes, reactive dyes, direct dyes, etc.) can be used, but the water resistance, dispersion stability and scratch resistance of the ink can be used. From the viewpoint of improving the properties, pigments and hydrophobic dyes are preferred. Among them, it is preferable to use a pigment in order to express the high weather resistance which has been recently demanded. Further, as will be described later, the colorant may be fine particles stable in the ink (hereinafter also simply referred to as “polymer particles containing a colorant”) using a surfactant or a polymer.

(Pigment)
The pigment may be either an inorganic pigment or an organic pigment.
Examples of the inorganic pigment include carbon black and metal oxide, and carbon black is particularly preferable for black ink.
Examples of organic pigments include azo pigments, diazo pigments, phthalocyanine pigments, quinacridone pigments, isoindolinone pigments, dioxazine pigments, perylene pigments, perinone pigments, thioindigo pigments, anthraquinone pigments, and quinophthalone pigments.
The hue is not particularly limited, and any chromatic pigment such as yellow, magenta, cyan, blue, red, orange, and green can be used.
Specific examples of preferred organic pigments include C.I. I. Pigment yellow, C.I. I. Pigment Red, C.I. I. Pigment orange, C.I. I. Pigment violet, C.I. I. Pigment blue, and C.I. I. One or more types of products selected from Pigment Green are listed.
Among these, quinacridone pigments are preferable from the viewpoint of improving the color developability of the ink.
Moreover, solid solution pigments, such as a quinacridone solid solution pigment, can also be used suitably. The quinacridone solid solution pigment includes β-type and γ-type unsubstituted quinacridone and 2,9-dimethylquinacridone (CI Pigment Red 122), or β-type and γ-type unsubstituted quinacridone and 2,9- It consists of dichloroquinacridone such as dichloroquinacridone, 3,10-dichloroquinacridone, and 4,11-dichloroquinacridone. As the quinacridone solid solution pigment, a solid solution pigment composed of a combination of unsubstituted quinacridone (CI Pigment Violet 19) and 2,9-dimethylquinacridone (CI Pigment Red 122) is preferable.

Self-dispersing pigments can also be used. Self-dispersing pigments are those in which one or more hydrophilic functional groups (anionic hydrophilic groups such as carboxy groups and sulfonic acid groups, or cationic hydrophilic groups such as quaternary ammonium groups) are directly or other atomic groups. It means an inorganic pigment or an organic pigment that can be dispersed in an aqueous medium without using a surfactant or a resin. Here, as other atomic groups, an alkanediyl group having 1 to 12 carbon atoms, a phenylene group, a naphthylene group, or the like can be given.
Examples of commercially available self-dispersing pigments include Cab-O-Jet 260M (a derivative of 2,9-dimethylquinacridone (CI Pigment Red 122)), 200, 300, 400, 270Y manufactured by Cabot Corporation. 470Y, 740Y, 554B, 480V, 352B, 260M, 265M, 465M, 250C, 450C, 1027R; BONJETBLACK CW-1, CW-2, M-800 manufactured by Orient Chemical Industry Co., Ltd .; Aqua manufactured by Tokai Carbon Co., Ltd. -Black 001, 162 and the like.
The pigments can be used alone or in admixture of two or more at any ratio.

(Coloring agents other than pigments)
The hydrophobic dye should just be what can be contained in a polymer particle, and the kind in particular is not restrict | limited. From the viewpoint of efficiently incorporating the dye in the polymer, the hydrophobic dye is 2 g / L or more, preferably 20 g / L or more and 500 g / L or less (25%) with respect to the organic solvent (preferably methyl ethyl ketone) used in the production of the polymer. C.) It is desirable to dissolve. Here, the hydrophobic dye means a dye having a solubility of preferably less than 6% by mass in 100 g of water (20 ° C.).
Examples of the hydrophobic dye include oil-soluble dyes and disperse dyes. Among these, oil-soluble dyes are preferable.
Examples of the oil-soluble dye include C.I. I. Solvent Black, C.I. I. Solvent Yellow, C.I. I. Solvent Red, C.I. I. Solvent Violet, C.I. I. Solvent Blue, C.I. I. Solvent Green, and C.I. I. One or more types of products selected from the group consisting of Solvent Orange are listed, which are commercially available from Orient Chemical Industry Co., Ltd., BASF Co., etc.
Colorants other than the pigment can be used alone or in admixture of two or more at any ratio.

(Polymer particles containing colorant)
When the colorant is used in water-based ink, it is preferable to use a surfactant and a polymer to form fine particles that are stable in the ink. In particular, from the viewpoint of obtaining a water-based ink having excellent adhesion to a resin recording medium such as PVC, rubbing resistance and alcohol resistance, it is more preferable to include a colorant in the water-insoluble polymer particles. It is further preferable to contain a pigment and / or a hydrophobic dye therein, and it is even more preferable to include a pigment and / or a hydrophobic dye in the water-insoluble polymer particles.
Below, the polymer particle containing a coloring agent is demonstrated.

From the viewpoint of improving the image density of the ink, the volume average particle diameter of the polymer particles containing the colorant is preferably 40 nm or more, more preferably 50 nm or more, and preferably 200 nm or less, more preferably 150 nm or less. is there.
The volume average particle diameter of the polymer particles containing the colorant is measured by a dynamic light scattering method, and specifically measured by the method of the example.

(Water-insoluble polymer)
For the polymer particles containing the colorant, it is preferable to use a water-insoluble polymer from the viewpoint of improving the water dispersibility of the polymer particles in the ink and the image density of the ink. Here, in this specification, the “water-insoluble polymer” means that when a polymer that has been dried at 105 ° C. for 2 hours and reaches a constant weight is dissolved in 100 g of water at 25 ° C., the dissolved amount is 10 g or less. A polymer is referred to, and the dissolved amount is preferably 5 g or less, more preferably 1 g or less. In the case of an anionic polymer, the dissolution amount is the dissolution amount when the anionic group of the polymer is neutralized 100% with sodium hydroxide.
Examples of water-insoluble polymers include polyesters, polyurethanes, vinyl polymers, and the like, which are obtained by addition polymerization of vinyl monomers (vinyl compounds, vinylidene compounds, vinylene compounds) from the viewpoint of improving the storage stability of the ink. Vinyl polymers are preferred.

  As a vinyl polymer, a monomer containing (a) an ionic monomer (hereinafter also simply referred to as “(a) component”) and (b) a hydrophobic monomer (hereinafter also simply referred to as “(b) component”). A vinyl polymer obtained by copolymerizing a mixture (hereinafter also simply referred to as “monomer mixture”) is preferable. This vinyl polymer has a structural unit derived from the component (a) and a structural unit derived from the component (b). Especially, what contains the structural unit derived from (c) macromonomer (henceforth only "(c) component") is preferable.

[(A) ionic monomer]
The (a) ionic monomer is preferably used as a monomer component of the water-insoluble polymer from the viewpoint of stably dispersing the polymer particles containing the colorant in the ink. (A) An anionic monomer and a cationic monomer are mentioned as a component, An anionic monomer is preferable.
Examples of the anionic monomer include a carboxylic acid monomer, a sulfonic acid monomer, and a phosphoric acid monomer.
Examples of the carboxylic acid monomer include acrylic acid, methacrylic acid, crotonic acid, itaconic acid, maleic acid, fumaric acid, citraconic acid, and 2-methacryloyloxymethyl succinic acid.
Among the anionic monomers, carboxylic acid monomers are preferable, and acrylic acid and methacrylic acid are more preferable from the viewpoint of improving dispersion stability of the polymer particles containing the colorant in the ink.

[(B) Hydrophobic monomer]
The (b) hydrophobic monomer is preferably used as a monomer component of the water-insoluble polymer from the viewpoint of improving the dispersion stability of the polymer particles containing the colorant in the ink. Examples of the hydrophobic monomer include alkyl (meth) acrylates and aromatic group-containing monomers.
As the alkyl (meth) acrylate, those having an alkyl group having 1 to 22 carbon atoms, preferably 6 to 18 carbon atoms are preferable. For example, methyl (meth) acrylate, ethyl (meth) acrylate, (iso) propyl (Meth) acrylate, (iso or tertiary) butyl (meth) acrylate, (iso) amyl (meth) acrylate, cyclohexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, (iso) octyl (meth) acrylate, ( Examples include iso) decyl (meth) acrylate, (iso) dodecyl (meth) acrylate, (iso) stearyl (meth) acrylate, and the like.
In addition, “(iso or tertiary)” and “(iso)” mean both cases in which these groups are present and cases in which these groups are not present. “(Meth) acrylate” refers to acrylate or methacrylate.

As the aromatic group-containing monomer, a vinyl monomer having an aromatic group having 6 to 22 carbon atoms, which may have a substituent containing a hetero atom, is preferable, and a styrenic monomer, an aromatic group-containing (meth) Acrylate is more preferred.
As the styrenic monomer, styrene, 2-methylstyrene, and divinylbenzene are preferable, and styrene is more preferable.
Moreover, as an aromatic group containing (meth) acrylate, benzyl (meth) acrylate, phenoxyethyl (meth) acrylate, etc. are preferable, and benzyl (meth) acrylate is more preferable.
(B) As for the hydrophobic monomer, two or more kinds of the above-mentioned monomers can be used, but a styrene monomer and an aromatic group-containing (meth) acrylate can be used in combination, and benzyl (meth) acrylate and styrene are used in combination. However, it is more preferable to use benzyl (meth) acrylate alone.

[(C) Macromonomer]
(C) The macromonomer is a compound having a polymerizable functional group at one end, preferably a number average molecular weight of 500 or more and 100,000 or less, and improves the dispersion stability of the polymer particles containing the colorant in the ink. From the viewpoint, it is preferably used as a monomer component of a water-insoluble polymer. The polymerizable functional group present at one end is preferably an acryloyloxy group or a methacryloyloxy group, and more preferably a methacryloyloxy group.
The number average molecular weight of the component (c) is more preferably 1,000 or more and 10,000 or less. The number average molecular weight is measured by gel permeation chromatography, and is measured using chloroform or the like as a solvent and polystyrene or the like as a standard substance.
The component (c) is preferably an aromatic group-containing monomer-based macromonomer or a silicone-based macromonomer, from the viewpoint of improving the dispersion stability of the polymer particles containing the colorant in the ink. Macromonomers are more preferred.
Examples of the aromatic group-containing monomer constituting the aromatic group-containing monomer-based macromonomer include the aromatic group-containing monomers described in the above (b) hydrophobic monomer, styrene and benzyl (meth) acrylate are preferred, and styrene is preferred. More preferred.
Specific examples of the styrenic macromonomer include AS-6 (S), AN-6 (S), HS-6 (S) (all trade names, manufactured by Toagosei Co., Ltd.), and the like.
Examples of the silicone macromonomer include organopolysiloxane having a polymerizable functional group at one end.

[(D) Nonionic monomer]
For the water-insoluble polymer, from the viewpoint of improving the dispersion stability of the polymer particles containing the colorant in the ink, (d) a nonionic monomer (hereinafter also simply referred to as “component (d)”) is used as the monomer. It is preferable to use it as a component.
(D) As a component, 2-hydroxyethyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, polypropylene glycol (n = 2-30, n shows the average addition mole number of an oxyalkylene group. The same hereafter). Polyalkylene glycol (meth) acrylates such as (meth) acrylate and polyethylene glycol (n = 2 to 30) (meth) acrylate; alkoxypolyalkylene glycols such as methoxypolyethylene glycol (n = 1 to 30) (meth) acrylate (meta ) Acrylate; phenoxy (ethylene glycol / propylene glycol copolymer) (n = 1 to 30, ethylene glycol: n = 1 to 29 therein) (meth) acrylate and the like. Among these, alkoxy polyalkylene glycol (meth) acrylate is preferable, and methoxypolyethylene glycol (n = 1 to 30) (meth) acrylate is more preferable.
Specific examples of the commercially available component (d) include NK Esters M-20G, 40G, 90G, and 230G from Shin-Nakamura Chemical Co., Ltd., Bremer PE-90 from NOF Corporation, 200, 350, PME-100, 200, 400, PP-500, 800, etc., AP-150, 400, 550, 50PEP-300, 50POEP-800B, 43PAPE-600B, etc. .
The components (a) to (d) can be used alone or in admixture of two or more.

Components (a) to (d) in the monomer mixture of the above-mentioned components (a) to (d) at the time of vinyl polymer production (contents as unneutralized amounts; the same applies hereinafter) or water-insoluble polymers The content of the structural unit derived from is as follows.
The content of the component (a) is preferably 2% by mass or more, more preferably 5% by mass or more, and still more preferably 8% by mass from the viewpoint of improving dispersion stability of the polymer particles containing the colorant in the ink. %, And preferably 40% by mass or less, more preferably 30% by mass or less, and still more preferably 25% by mass or less.
The content of the component (b) is preferably 5% by mass or more, more preferably 10% by mass or more, and preferably from the viewpoint of improving dispersion stability of the polymer particles containing the colorant in the ink. Is 98% by mass or less, more preferably 90% by mass or less, and still more preferably 80% by mass or less.
When the component (c) is contained, the content of the component (c) is preferably 1% by mass or more, more preferably 5 from the viewpoint of improving dispersion stability of the polymer particles containing the colorant in the ink. It is at least mass%, and is preferably at most 25 mass%, more preferably at most 20 mass%.
In the case of containing the component (d), the content of the component (d) is preferably 5% by mass or more, more preferably 10 from the viewpoint of improving dispersion stability of the polymer particles containing the colorant in the ink. It is at least 50% by mass, and preferably at most 50% by mass, more preferably at most 40% by mass.

  Further, the mass ratio of [(a) component / [(b) component + (c) component]] when the component (c) is contained is determined by the dispersion stability of the polymer particles containing the colorant in the ink and From the viewpoint of improving the image density of the ink, it is preferably 0.01 or higher, more preferably 0.02 or higher, still more preferably 0.03 or higher, still more preferably 0.05 or higher, still more preferably 0.10 or higher. And is preferably 1 or less, more preferably 0.67 or less, and still more preferably 0.50 or less.

(Production of water-insoluble polymer)
The water-insoluble polymer used in the present invention is produced by copolymerizing a monomer mixture by a known polymerization method. As the polymerization method, a solution polymerization method is preferable.
As the solvent used in the solution polymerization method, for example, polar organic solvents such as aliphatic alcohols having 1 to 3 carbon atoms, ketones having 3 to 5 carbon atoms, ethers, and esters are preferable. , Ethanol, acetone, and methyl ethyl ketone, and methyl ethyl ketone is preferable.
In the polymerization, a polymerization initiator or a polymerization chain transfer agent can be used. As the polymerization initiator, an azo compound is preferable, and 2,2′-azobis (2,4-dimethylvaleronitrile) is more preferable. . As the polymerization chain transfer agent, mercaptans are preferable, and 2-mercaptoethanol is more preferable.

Although preferable polymerization conditions vary depending on the type of polymerization initiator and the like, the polymerization temperature is preferably 50 ° C. or higher, more preferably 60 ° C. or higher, and preferably 90 ° C. or lower, more preferably 85 ° C. or lower. The polymerization time is preferably 1 hour or longer, more preferably 1.2 hours or longer, and preferably 20 hours or shorter, more preferably 10 hours or shorter. The polymerization atmosphere is preferably a nitrogen gas atmosphere or an inert gas atmosphere such as argon.
After completion of the polymerization reaction, the produced polymer can be isolated from the reaction solution by a known method such as reprecipitation or solvent distillation. In addition, unreacted monomers and the like can be removed from the obtained polymer by reprecipitation, membrane separation, chromatography, extraction, and the like.

  The weight average molecular weight of the water-insoluble polymer used in the present invention is preferably 5,000 from the viewpoint of improving the dispersion stability of the polymer particles containing the colorant in the ink and the image density of the ink. Or more, more preferably 10,000 or more, still more preferably 20,000 or more, and preferably 500,000 or less, more preferably 400,000 or less, still more preferably 300,000 or less, and even more preferably 200. , 000 or less. In addition, the measurement of a weight average molecular weight can be performed by the method as described in an Example.

<Production of polymer particles containing colorant>
The polymer particles containing the colorant are preferably produced by a method having the following steps A and B as an aqueous dispersion.
Step A: A dispersion containing a water-insoluble polymer, an organic solvent, a colorant, water, and, if necessary, a mixture containing a neutralizing agent, a surfactant and the like is dispersed to obtain a dispersion of polymer particles containing the colorant. Step Step B: Step of removing the organic solvent from the dispersion obtained in Step A to obtain an aqueous dispersion of polymer particles containing a colorant. Further, Step C may be performed.
Step C: Step of cross-linking polymer particles containing a colorant by mixing the aqueous dispersion obtained in Step B and a cross-linking agent.

(Process A)
In step A, first, a water-insoluble polymer is dissolved in an organic solvent to obtain a water-insoluble polymer solution. Next, a colorant, water, and if necessary, a neutralizing agent, a surfactant and the like are added to the obtained water-insoluble polymer solution and mixed to disperse the polymer particles containing the oil-in-water colorant. A method of obtaining a body is preferred. The order of adding water, neutralizing agent, and coloring agent to the solution of the water-insoluble polymer is preferably, for example, added in the order of water, neutralizing agent, and coloring agent.
Examples of the organic solvent for dissolving the water-insoluble polymer include aliphatic alcohols having 1 to 3 carbon atoms, ketones having 3 to 5 carbon atoms, ethers, esters, and the like, and those having 3 to 5 carbon atoms. Ketones are more preferred, and methyl ethyl ketone is even more preferred. When a water-insoluble polymer is synthesized by a solution polymerization method, the solvent used in the polymerization may be used as it is.
When the water-insoluble polymer is an anionic polymer, an anionic group in the water-insoluble polymer may be neutralized using a neutralizing agent. When neutralizing with a neutralizing agent, it is preferable to neutralize so that the pH is preferably 7 or more, and preferably 11 or less. Examples of the neutralizing agent include bases such as lithium hydroxide, sodium hydroxide, potassium hydroxide, ammonia, and various amines. Further, the water-insoluble polymer may be neutralized in advance.
The degree of neutralization of the anionic group of the water-insoluble polymer is preferably at least 10 mol%, more preferably 20 mol, from the viewpoint of improving the dispersion stability of the polymer particles containing the colorant in the ink and in the aqueous medium. % Or more, more preferably 30 mol% or more, and preferably 300 mol% or less, more preferably 200 mol% or less, still more preferably 150 mol% or less.
Here, the “neutralization degree” means a value obtained by dividing the molar equivalent of the neutralizing agent by the molar amount of the anionic group of the water-insoluble polymer.

In the dispersion of polymer particles containing the colorant, the colorant is preferably 5% by mass or more, more preferably 10% by mass or more, and preferably 50% by mass or less, more preferably 40% by mass or less. It is.
In the dispersion of polymer particles containing the colorant, the organic solvent is preferably 10% by mass or more, and preferably 70% by mass or less, more preferably 50% by mass or less.
In the dispersion of polymer particles containing the colorant, the water-insoluble polymer is preferably 2% by mass or more, more preferably 3% by mass or more, and preferably 40% by mass or less, more preferably 20% by mass. It is as follows. Water is preferably 10% by mass or more, more preferably 20% by mass or more, and preferably 70% by mass or less.
The mass ratio of the amount of the colorant to the amount of the water-insoluble polymer [colorant / water-insoluble polymer] is preferably from the viewpoint of improving the dispersion stability of the polymer particles containing the colorant in the ink and in the aqueous medium. Is 50/50 or more, more preferably 60/40 or more, still more preferably 70/30 or more, and preferably 90/10 or less, more preferably 80/20 or less.

  As the dispersion method of the dispersion in the step A, for example, the volume average particle diameter of the polymer particles containing the colorant can be atomized only to the main dispersion until a desired particle diameter is obtained, but it is preferably predispersed. Thereafter, it is preferable to carry out the main dispersion by further applying a shearing stress, and to control the volume average particle size of the polymer particles containing the colorant to a desired particle size. The temperature in the dispersion of step A is preferably 0 ° C. or higher, and preferably 40 ° C. or lower, more preferably 25 ° C. or lower. The dispersion time in step A is preferably 1 hour or longer, more preferably 2 hours or longer, and preferably 30 hours or shorter, more preferably 25 hours or shorter.

When the dispersion is predispersed, a commonly used mixing and stirring device such as an anchor blade or a disper blade, particularly a high-speed stirring and mixing device is preferable.
Examples of means for imparting the shear stress of this dispersion include a kneader such as a roll mill and a kneader, a high-pressure homogenizer such as a microfluidizer (trade name, manufactured by Microfluidics), a media-type disperser such as a paint shaker and a bead mill. . Examples of commercially available media type dispersers include Ultra Apex Mill (trade name, manufactured by Kotobuki Industries Co., Ltd.), Picomill (trade name, manufactured by Iwata Iron Works Co., Ltd.), and the like. A plurality of these devices can be combined. Among these, it is preferable to use a high-pressure homogenizer from the viewpoint of reducing the particle size of the polymer particles containing the colorant.

(Process B)
In Step B, an aqueous dispersion of polymer particles containing a colorant can be obtained by removing the organic solvent from the dispersion obtained in Step A by a known method. The organic solvent in the aqueous dispersion containing the polymer particles containing the obtained colorant is preferably substantially removed, but may remain as long as the object of the present invention is not impaired. The amount of the residual organic solvent is preferably 0.1% by mass or less, and more preferably 0.01% by mass or less.
If necessary, the dispersion can be heated and stirred before the organic solvent is distilled off.
The obtained aqueous dispersion of polymer particles containing a colorant is obtained by dispersing solid polymer particles containing a colorant in a medium containing water as a main medium. Here, the form of the polymer particles is not limited as long as the particles are formed of at least a colorant and a water-insoluble polymer. For example, a particle form in which a colorant is included in the water-insoluble polymer, a particle form in which the colorant is uniformly dispersed in the water-insoluble polymer, a particle form in which the colorant is exposed on the surface of the water-insoluble polymer particle, and the like. And may be a mixture thereof.

Further, from the viewpoint of the storage stability of the aqueous dispersion and the water-based ink, step C may be further performed following step A and step B described above.
(Process C)
Step C is a step of mixing the aqueous dispersion obtained in Step B and a crosslinking agent to crosslink the polymer particles containing the colorant.
Here, when the water-insoluble polymer is an anionic water-insoluble polymer having an anionic group, the cross-linking agent is preferably a compound having a functional group that reacts with the anionic group. A compound having 2 to 6 is more preferable.
Preferred examples of the crosslinking agent include compounds having two or more epoxy groups in the molecule, compounds having two or more oxazoline groups in the molecule, and compounds having two or more isocyanate groups in the molecule. A compound having two or more epoxy groups in the molecule is more preferable, and trimethylolpropane polyglycidyl ether is still more preferable.

The amount of the crosslinking agent used is preferably 0.3 / 100 or more, more preferably 1 in terms of the mass ratio of [crosslinking agent / anionic water-insoluble polymer] from the viewpoint of improving the storage stability of the aqueous dispersion and the ink. / 100 or more, more preferably 5/100 or more, and preferably 50/100 or less, more preferably 40/100 or less, and still more preferably 25/100 or less.
The obtained aqueous dispersion of polymer particles containing the colorant is preferably filtered through a wire mesh or the like to remove coarse particles and the like. In addition, from the viewpoint of improving the productivity and storage stability of the aqueous dispersion, various additives such as organic solvents, preservatives, and antifungal agents, which are arbitrarily added to the aqueous ink described later, include a colorant. It may be added to an aqueous dispersion of polymer particles.
The solid content concentration of the aqueous dispersion of polymer particles containing a colorant is the viewpoint of improving the productivity and storage stability of the aqueous dispersion, as well as the adhesion to a resin recording medium such as PVC, the abrasion resistance, and the like. From the viewpoint of obtaining a water-based ink having excellent alcohol resistance, it is preferably 5% by mass or more, more preferably 10% by mass or more, still more preferably 15% by mass or more, and preferably 50% by mass or less, more preferably 45%. It is not more than mass%, more preferably not more than 40 mass%, still more preferably not more than 35 mass%.

<Optional components of water-based ink>
Various additives such as organic solvents, penetrants, dispersants, surfactants, viscosity modifiers, antifoaming agents, antiseptics, antifungal agents, and rust inhibitors can be added to the aqueous ink of the present invention. .
As the organic solvent, in addition to the dialkyl ketone having an alkyl group having 1 to 3 carbon atoms, glycerin, propylene glycol, 1,2-butanediol, 1,2-hexanediol, diethylene glycol, ethylene glycol, acetylene glycol Polyhydric alcohols such as 2-pyrrolidone, pyrrolidone such as 2-pyrrolidone, and glycol ethers such as triethylene glycol monobutyl ether and polyoxyethylene lauryl ether are preferable, and two or more of these are more preferably used in combination.

<Content of each component in water-based ink for inkjet recording>
The content of the colorant contained in the water-based ink of the present invention is preferably the water-based ink from the viewpoint of obtaining a water-based ink having excellent adhesion to a resin recording medium such as PVC, abrasion resistance and alcohol resistance. 1% by mass or more, more preferably 2% by mass or more, further preferably 3% by mass or more, and preferably 25% by mass or less, more preferably 10% by mass or less, and further preferably 5% by mass or less.
The content of the polyester resin particles (A) contained in the water-based ink of the present invention is such that the discharge property of the water-based ink is improved, and adhesion to a resin recording medium such as PVC, scratch resistance, and alcohol resistance. From the viewpoint of obtaining a water-based ink having excellent properties, it is preferably 1% by mass or more, more preferably 2% by mass or more, still more preferably 3% by mass or more, and preferably 15% by mass or less in the water-based ink. Preferably it is 10 mass% or less, More preferably, it is 7 mass% or less.

The content of water contained in the aqueous ink of the present invention is preferably 25% by mass or more, more preferably 30% by mass or more, and still more preferably 35% in the aqueous ink from the viewpoint of improving the dischargeability of the aqueous ink. More preferably, it is 90 mass% or less, More preferably, it is 80 mass% or less, More preferably, it is 70 mass% or less.
The mass ratio of the colorant to the polyester resin particles (A) contained in the water-based ink of the present invention [colorant / polyester resin particles (A)] is a viewpoint of improving the discharge property of the water-based ink and a resin such as PVC. From the viewpoint of obtaining a water-based ink having excellent adhesion to a recording medium, rubbing resistance and alcohol resistance, the water-based ink is preferably 20/80 to 70/30, more preferably 30/70 to 60/40, More preferably, it is 40 / 60-50 / 50, More preferably, it is 40 / 60-48 / 52.

The content of the organic solvent that can be used in the present invention is preferably 5% by mass or more, more preferably 10% by mass or more in the water-based ink, from the viewpoint of improving the dischargeability of the water-based ink, and Preferably it is 40 mass% or less, More preferably, it is 35 mass% or less.
The content of the surfactant that can be used in the present invention is preferably 0.1% by mass or more, more preferably 0.5% by mass or more in the water-based ink from the viewpoint of improving the dischargeability of the water-based ink. And preferably 5% by mass or less, more preferably 2% by mass or less.

  The above-described water-based ink for ink-jet recording of the present invention is excellent in adhesion to a resin recording medium such as PVC, scratch resistance, and alcohol resistance.For example, by using it in the ink-jet recording method of the present invention described later, Adhesion to a resin recording medium such as PVC, abrasion resistance and alcohol resistance can be further improved.

[Method for producing water-based ink for inkjet recording]
The water-based ink for ink-jet recording of the present invention can be suitably produced by going through the following steps (1) to (3).
Step (1): 2 mol% or more and 12 mol% of an alcohol component containing an aliphatic diol having 3 to 6 carbon atoms and having a hydroxy group bonded to a secondary carbon atom, and a trivalent or higher polyvalent carboxylic acid Step of polycondensation of carboxylic acid component contained below to obtain polyester Step (2): Step of obtaining an aqueous dispersion of polyester resin particles (A) by mixing a polyester-containing resin with an aqueous medium Step (3) ): A step of mixing the aqueous dispersion of the polyester resin particles (A) obtained in the step (2) with an aqueous dispersion containing a colorant to obtain a water-based ink for inkjet recording.

[Step (1)]
Step (1) is as described above.
[Step (2)]
Step (2) is also as described above.
<Step (3)>
In the step (3), the aqueous dispersion of the polyester resin particles (A) obtained in the step (2), the aqueous dispersion containing the colorant, and the optional components described above may be mixed as necessary. Good. Next, the suitable example of a process (3) is demonstrated.
First, water such as ion-exchanged water, and at least one of an organic solvent and various additives as optional components are mixed as necessary, and stirred as necessary to obtain a mixed solution.
Next, this mixed solution is mixed with an aqueous dispersion containing a colorant, and further stirred and mixed while dropping the aqueous dispersion of the polyester resin particles (A) obtained in the step (2). Accordingly, water-based ink can be suitably obtained by filtering with a filter or the like.

[Inkjet recording method]
In the ink jet recording method of the present invention, the water-based ink containing the colorant and the polyester resin particles (A) is attached to a resin recording medium by an ink jet recording method, and then the resin recording medium is 40 ° C. or more and 100 ° C. or less. This is an ink jet recording method in which the ink is heated.
In the ink jet recording method of the present invention, since a resin recording medium such as PET or PVC is used as the recording medium, the adhesion to the resin recording medium such as PVC, which is the effect of the water-based ink of the present invention, and abrasion resistance and Alcohol resistance can be exhibited more.
In the present invention, after the water-based ink is attached to the resin recording medium, the resin recording medium is heated to 40 ° C. or higher and 100 ° C. or lower, so that the polyester constituting the polyester resin particles (A) in the water-based ink , It diffuses on the printing surface of the recording medium on the film and acts as a fixing aid for the colorant when a coating film is formed. Therefore, the adhesion to a resin recording medium such as PVC, abrasion resistance, and alcohol resistance can be further improved.
The heating temperature of the resin recording medium is preferably 50 ° C. or higher, more preferably 60 ° C. or higher, from the viewpoint of improving adhesion to a resin recording medium such as PVC, rubbing resistance and alcohol resistance. And it is 90 degrees C or less preferably, More preferably, it is 85 degrees C or less.

In the following production examples, examples and comparative examples, “%” means “% by mass” and “parts” means “parts by mass” unless otherwise specified. Each physical property was measured by the following method.
[Acid value of polyester]
The measurement was performed according to JIS K0070. However, the solvent specified in JIS K0070 was changed from a mixed solvent of ethanol and ether to a mixed solvent of acetone and toluene (acetone: toluene = 1: 1 (volume ratio)).

[Softening point of polyester]
Using a flow tester (product name: “CFT-500D”, manufactured by Shimadzu Corporation), a 1 g sample was heated at a heating rate of 6 ° C./min, a 1.96 MPa load was applied by a plunger, and the diameter was 1 mm. And extruded from a 1 mm long nozzle. The amount of plunger drop of the flow tester was plotted against the temperature, and the temperature at which half of the sample flowed out was taken as the softening point.

[Glass transition temperature of polyester]
Using a differential scanning calorimeter (DSC, product name: “Q-100”, manufactured by T.A. Instruments Japan Co., Ltd.), 0.01 to 0.02 g of a sample was weighed into an aluminum pan, and 200 ° C. Then, the sample for measurement was prepared by cooling from 200 ° C. to 0 ° C. at a temperature decrease rate of 10 ° C./min. Then, the temperature is increased at a rate of temperature increase of 10 ° C / min, and the glass transition takes place at the intersection of the base line extension below the endothermic peak temperature and the tangent that indicates the maximum slope from the peak rise to the peak apex. It was temperature.

[Weight average molecular weight and number average molecular weight of polyester]
The weight average molecular weight (Mw) and the number average molecular weight (Mn) were measured by the gel permeation chromatography (GPC) method shown below.
(1) Preparation of sample solution The sample was dissolved in tetrahydrofuran at 25 ° C. so that the concentration was 0.5 g / 100 mL, and this solution was then added to a fluororesin filter (product name: “DISMIC”) having a pore size of 0.2 μm. And a model solution “25JP” (manufactured by ADVANTEC) to remove insoluble components to obtain a sample solution.
(2) Measurement Using the following measuring apparatus and analytical column, tetrahydrofuran is flowed as an eluent at a flow rate of 1 mL / min, the column is stabilized in a constant temperature bath at 40 ° C., and 100 μL of the sample solution is injected therein. The molecular weight was measured. The molecular weight (Mw, Mn) of the sample was determined by several types of monodisperse polystyrene (product name: “TSKgel standard polystyrene”; type name (Mw): “A-500 (5.0 × 10 ² )”, “A-1000 ( 1.01 × 10 ³ ) ”,“ A-2500 (2.63 × 10 ³ ) ”,“ A-5000 (5.97 × 10 ³ ) ”,“ F-1 (1.02 × 10 ⁴ ) ” , “F-2 (1.81 × 10 ⁴ )”, “F-4 (3.97 × 10 ⁴ )”, “F-10 (9.64 × 10 ⁴ )”, “F-20 (1. 90 × 10 ⁵ ) ”,“ F-40 (4.27 × 10 ⁵ ) ”,“ F-80 (7.06 × 10 ⁵ ) ”,“ F-128 (1.09 × 10 ⁶ ) ”; Was also calculated based on a previously prepared calibration curve.
<Measurement conditions>
Measuring device: “HLC-8220GPC” (product name, manufactured by Tosoh Corporation)
Analytical column: “GMHXL” + “G3000HXL” (both product names, manufactured by Tosoh Corporation)
Column temperature: 40 ° C
Flow rate: 1 mL / min

[Ester group concentration of polyester]
The ester group concentration of the polyester was calculated from the following formula.
Ester group concentration (mmol / g) = A / B
In the formula, A is the number of moles of the ester group of the polyester (mmol), and B is the mass (g) of the polyester, each calculated from the following formula.
<About A>
(I) When the alcohol component is excessive with respect to the carboxylic acid component A (mmol) = [number of moles of charged 2 × divalent carboxylic acid component (mmol) + number of moles of charged 3 × 3 carboxylic acid component (mmol) )] × reaction rate (ii) When the carboxylic acid component is excessive with respect to the alcohol component A (mmol) = 2 × number of moles of the alcohol component charged (mmol) × reaction rate <about B>
B (g) = total charge mass of carboxylic acid component and alcohol component (g)-mass of water produced during polyester synthesis (g)
The reaction rate and the mass of water produced during polyester synthesis were calculated from the following equations.
(1) Reaction rate when alcohol component is excessive with respect to carboxylic acid component Reaction rate = 1- [Acid value of polyester (mgKOH / g) / Acid value at the time of charging raw material monomer (mgKOH / g)]
Here, the acid value at the time of charging the raw material monomer is [number of charged moles of 2 × divalent carboxylic acid component (mmol) + number of charged moles of 3 × trivalent carboxylic acid component (mmol)] × 56.1 / carboxylic The total charge mass (g) of the acid component and the alcohol component was used.
(2) Reaction rate when carboxylic acid component is excessive with respect to alcohol component Reaction rate = hydroxyl value of polyester (mgKOH / g) / hydroxyl value at the time of charging raw material monomer (mgKOH / g)
Here, the hydroxyl value at the time of charging the raw material monomer was defined as 2 × total charged moles of alcohol component (mmol) × 56.1 / total charged mass (g) of carboxylic acid component and alcohol component.
(3) Mass of water generated during resin synthesis Mass of water generated during resin synthesis (g) = 18 (molecular weight of water) × A

[Volume Average Particle Size (D _V ) of Polyester Resin Particles]
The volume average particle diameter (D _V ) was measured under the following conditions using a dynamic light scattering particle size measuring instrument (product name: “ZETASIZER NANO ZS”, manufactured by Malvern).
Solid content concentration: 0.1% by mass
Measurement temperature: 25 ° C
Medium: Water Measurement cell: Glass Cuvette
Laser specifications: He-Ne, 4mW, 633nm
Detection optical system: NIBS, 173 ° C.
Number of measurements: 10 times Isothermal time: 5 minutes Analysis software: Zeta Sizer Software 6.2
Analysis method: General Purpose Mode (cumulant method)

[Solid content concentration of aqueous dispersion of polyester resin particles]
Using an infrared moisture meter (product name: “FD-230”, manufactured by Kett Scientific Laboratory Co., Ltd.), 5 g of an aqueous dispersion was measured at a drying temperature of 150 ° C. and a measurement mode 96 (monitoring time 2.5 minutes / variation range 0. 05%), and the water content (mass%) of the aqueous dispersion was measured. The solid content concentration was calculated according to the following formula.
Solid content concentration (% by mass) = 100-water content (% by mass)

[PH of aqueous dispersion of polyester resin particles]
It measured at 25 degreeC using the pH meter (Product name: "HM-20P", the Toa DK Corporation make).

[Weight average molecular weight of water-insoluble polymer (anionic polymer)]
Using the following measuring device and analytical column, gel permeation chromatography using a solution in which phosphoric acid and lithium bromide are dissolved in N, N-dimethylformamide at concentrations of 60 mmol / L and 50 mmol / L, respectively, as an eluent Measured by the method. The molecular weight (Mw, Mn) of the sample is several types of monodisperse polystyrene (product name: “TSKgel standard polystyrene”; type names: “A-500”, “A-2500”, “F-1”, “F-10”). “All of them were manufactured by Tosoh Corporation) as a standard sample and calculated based on a calibration curve prepared in advance. The sample was dissolved in N, N-dimethylformamide to give a solution having a solid content of 0.3% by mass.
<Measurement conditions>
Measuring device: “HLC-8120GPC” (product name, manufactured by Tosoh Corporation)
Analysis column: “TSK-GEL α-M” × 2 (product name, manufactured by Tosoh Corporation)
Column temperature: 40 ° C
Flow rate: 1 mL / min

[Solid content concentration of aqueous dispersion of polymer particles containing colorant (pigment-containing anionic polymer particles)]
To a 30 mL polypropylene container (inner diameter = 40 mm, height = 30 mm), weigh 10.0 g of sodium sulfate constant in a desiccator, add approximately 1.0 g of the sample to this, mix, and accurately The sample was weighed and maintained at 105 ° C. for 2 hours to remove volatile components, and further left in a desiccator for 15 minutes to measure the mass. The mass of the sample after removing the volatile matter was taken as the solid content and divided by the mass of the added sample to obtain the solid content concentration.

[Volume Average Particle Size (D _V ) of Polymer Particles Containing Colorant (Pigment-Containing Anionic Polymer Particles)]
Using a laser particle analysis system (product name: “ELS-8000”, manufactured by Otsuka Electronics Co., Ltd.), cumulant analysis was performed for measurement. A dispersion diluted with water so that the concentration of particles to be measured was about 5 × 10 ⁻³ mass% was used. The measurement conditions were a temperature of 25 ° C., an angle between incident light and a detector of 90 °, and the number of integrations of 100. The refractive index of water (1.333) was input as the refractive index of the dispersion solvent.

[Evaluation of adhesion]
1.0 g of water-based ink was applied to a PVC film (product name: “Transparent PVC RE-137”, manufactured by MIMAKI ENGINEERING CO., LTD.) No. A sample was prepared by coating with a 20 wire bar, drying for 10 minutes with a dryer at 80 ° C., and allowing to stand in an environment room at room temperature of 25 ° C. and relative humidity of 50% for one day. Thereafter, a 4 cm long tape (product name: “Cello Tape CT15” (registered trademark), manufactured by Nichiban Co., Ltd.) is attached to the coated surface of the sample, and the tape is peeled off at a speed of 10 cm / sec at an angle of 90 °. The remaining area of the coated surface was visually evaluated in the following 11 stages. The higher the score, the better the adhesion to PVC.
<Evaluation criteria>
Remaining area 100%: 10 points Remaining area 90% to less than 100%: 9 points Remaining area 80% to less than 90%: 8 points Remaining area 70% to less than 80%: 7 points Remaining area 60% to less than 70%: 6 Points Remaining area 50% or more and less than 60%: 5 points Remaining area 40% or more and less than 50%: 4 points Remaining area 30% or more and less than 40%: 3 points Remaining area 20% or more and less than 30%: 2 points Remaining area 10% or more Less than 20%: 1 point Remaining area less than 10%: 0 point

[Evaluation of abrasion resistance]
1.0 g of water-based ink was applied to a PVC film (product name: “Transparent PVC RE-137”, manufactured by MIMAKI ENGINEERING CO., LTD.) No. A sample was prepared by coating with a 20 wire bar, drying for 10 minutes with a dryer at 80 ° C., and allowing to stand in an environment room at room temperature of 25 ° C. and relative humidity of 50% for one day. Using a Gakushin friction tester (product name: “RT-300”, manufactured by Daiei Kagaku Seiki Seisakusho Co., Ltd.), the coated surface of the sample was non-woven fabric (trade name: “Bencot” (registered trademark), Asahi Kasei Corporation. After being rubbed at a load of 500 g / 200 times, the state of the coated surface was visually evaluated in the following five stages. The higher the score, the better the abrasion resistance.
<Evaluation criteria>
No scratches or peeling: 5 points Scratches on a part of the coated surface: 4 points Scratches on the whole coated surface: 3 points Scratches on the whole coated surface and partly peeled: 2 points There is peeling on the whole coated surface: 1 point

[Evaluation of alcohol resistance]
1.0 g of water-based ink was applied to a PVC film (product name: “Transparent PVC RE-137”, manufactured by MIMAKI ENGINEERING CO., LTD.) No. A sample was prepared by coating with a 20 wire bar, drying for 10 minutes with a dryer at 80 ° C., and allowing to stand in an environment room at room temperature of 25 ° C. and relative humidity of 50% for one day. A cotton swab impregnated with an aqueous solution of ethanol adjusted at a concentration of 0 to 100% by weight every 10% by weight, while making the load on the coated surface of the sample as small as possible, with a width of 2 to 3 cm, 1 reciprocation per second At this speed, the coated surface was rubbed so as to stroke 10 times. The state of the coated surface was evaluated by visual observation, and the highest ethanol concentration at which no changes such as scratches, peeling and cloudiness were observed on the coated surface before and after rubbing was used as an index of alcohol resistance. The higher the concentration, the better the alcohol resistance.

Production Examples 1-8
<Manufacture of polyesters A to H>
The raw material monomer and the esterification catalyst 1 shown in Tables 1 and 2 were placed in a 10-liter four-necked flask equipped with a thermometer, a stainless steel stirring rod, a flow-down condenser and a nitrogen inlet tube, and in a mantle heater in a nitrogen atmosphere. The temperature was raised to 180 ° C. Then, after heating up to 210 degreeC over 5 hours, it was made to react at 210 degreeC, it confirmed that the reaction rate reached | attained 70% or more, it cooled to 160 degreeC, and the esterification catalyst 2 was added. Then, it heated up to 220 degreeC, and it was made to react until it reached the softening point of Table 1 at 8.0 kPa, and polyester AH was obtained. The reaction rate means a value of the amount of generated reaction water (mol) / theoretical amount of generated water (mol) × 100.
The physical properties of the obtained polyesters A to H are shown in Tables 1 and 2.

Production Example 9
<Manufacture of polyester I>
Into a 10 liter four-necked flask equipped with a thermometer, a stainless steel stirring bar, a flow-down condenser and a nitrogen inlet tube, polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane 7, 548 g, 2,452 g of fumaric acid, and 50 g of 4-tert-butylcatechol were added, heated to 210 ° C. over 5 hours with stirring in a nitrogen atmosphere, held at 210 ° C. for 2 hours, and then the pressure in the flask The polyester I was obtained by reacting to a desired softening point at 8.3 kPa.
Table 2 shows the physical properties of the obtained polyester I.

Production Examples 10 to 18
<Production of aqueous dispersions a to i of polyester resin particles>
A four-necked flask equipped with a nitrogen inlet tube, a reflux condenser, a stirrer (product name: “Three-One Motor BL300”, manufactured by Shinto Kagaku Co., Ltd.) and a thermocouple, has the types and amounts shown in Tables 1 and 2. Polyester was added and mixed with 200 g of methyl ethyl ketone at 30 ° C. to dissolve. Next, 5% aqueous sodium hydroxide solution in the amount shown in Tables 3 and 4 was added and stirred for 30 minutes, then deionized water was added dropwise at a rate of 20 mL / min with stirring at 30 ° C., and the temperature was raised to 60 ° C. . Subsequently, methyl ethyl ketone was distilled off at 60 ° C. while reducing the pressure stepwise from 80 kPa to 30 kPa, and a part of water was removed. After cooling to 25 ° C., the mixture was filtered through a 150-mesh wire mesh, the solid content concentration was adjusted to 30% by mass with ion-exchanged water, and an aqueous dispersion of polyester resin particles was obtained.
Tables 3 and 4 show the physical properties of the obtained aqueous dispersion of polyester resin particles.

Production Example 19
<Preparation of aqueous dispersion of water-insoluble polymer particles containing colorant (pigment)>
(1) Synthesis of water-insoluble polymer (anionic polymer) 399 parts of benzyl methacrylate (manufactured by Wako Pure Chemical Industries, Ltd.), 91 parts of methacrylic acid (manufactured by Wako Pure Chemical Industries, Ltd.), methoxypolyethylene glycol methacrylate (product name: “ M-230G ", manufactured by Shin-Nakamura Chemical Co., Ltd., 140 parts by average added mole number of oxyethylene groups: 23, styrene macromonomer (product name:" AS-6S ", manufactured by Toagosei Co., Ltd., solid content: 50 %) 140 parts were mixed to prepare a monomer mixture (770 parts). In a reaction vessel, 15.75 parts of methyl ethyl ketone, 0.350 part of a polymerization chain transfer agent (2-mercaptoethanol) and 10% (77 parts) of the monomer mixture were mixed and subjected to nitrogen gas replacement.
Meanwhile, 80% (616 parts) of the monomer mixture, 2.45 parts of the polymerization chain transfer agent, 173.25 parts of methyl ethyl ketone, and a polymerization initiator 2,2′-azobis (2,4-dimethylvalero) were added to the dropping funnel. Nitrile) (Product name: “V-65”, manufactured by Wako Pure Chemical Industries, Ltd.) 5.6 parts was added, and the temperature was raised to 75 ° C. while stirring the mixed solution in the reaction vessel under a nitrogen atmosphere. Then, the mixed solution in the dropping funnel was dropped over 4.5 hours. Then, the remaining 10% (77 parts) of the monomer mixture, 0.7 parts of the polymerization chain transfer agent, 126 parts of methyl ethyl ketone and 1.4 parts of the polymerization initiator were mixed at 75 ° C. as a second drop. It was added dropwise over 1.7 hours.
After the completion of dropping, 2.1 parts of the initiator was mixed, heated to 80 ° C., and stirred for 1.5 hours. This initiator was mixed, heated and stirred twice to obtain a polymer solution (polymer weight average molecular weight: 26,000).

(2) Production of aqueous dispersion of pigment-containing water-insoluble polymer particles (pigment-containing anionic polymer particles) The polymer solution obtained by the synthesis of water-insoluble polymer (anionic polymer) in (1) above is dried under reduced pressure. 20 parts of the resulting polymer was dissolved in 62.8 parts of methyl ethyl ketone, and 5.01 part of 5N aqueous sodium hydroxide, 1.13 parts of 25% aqueous ammonia, and 236.5 parts of ion-exchanged water were contained therein. In addition, the mixture was stirred and mixed at 2,000 r / min for 15 minutes at 10 to 15 ° C. using a disper blade.
Subsequently, 45 parts of magenta pigment: PV19 (product name: “Inkjet Magenta E5B02”, manufactured by Clariant Japan Co., Ltd.) and 25 parts of magenta pigment: PR122 (product name: “6111T”, manufactured by Dainichi Seika Kogyo Co., Ltd.) were added. The mixture was stirred and mixed at 7,000 r / min for 3 hours at 10 to 15 ° C. using a disper blade. The obtained dispersion was filtered through 200 mesh and subjected to a 20-pass dispersion treatment at a pressure of 150 MPa using a microfluidizer “M-110K” (manufactured by Microfluidics, high-pressure homogenizer).
Methyl ethyl ketone was removed from the obtained dispersion at 60 ° C. under reduced pressure, a part of water was further removed, the mixture was centrifuged, and the liquid layer portion was filtered through a filter having a pore size of 5 μm (manufactured by Sartorius Stedim Biotech) to obtain a coarse particle. Particles were removed. Further, 80 parts of this dispersion was mixed with 0.2 part of a preservative (product name: “Proxel XL2”, manufactured by Avisia) and 19.8 parts of ion-exchanged water, and sterilized at 70 ° C. for 1 hour. Thereafter, the mixture is cooled to 25 ° C. and filtered through a filter having a pore size of 5 μm, whereby an aqueous dispersion (solid content concentration: 20% by mass, volume average) of water-insoluble polymer particles containing pigment (pigment-containing anionic polymer particles). Particle size: 133 nm).

Examples 1-5 and Comparative Examples 1-4
<Manufacture of water-based ink>
Propylene glycol (manufactured by Wako Pure Chemical Industries, Ltd.) 20.0 parts, 1,2-butanediol (manufactured by Wako Pure Chemical Industries, Ltd.) 10.0 parts, wetting agent (product name: “Orphine E1010”) (Orphine is a registered trademark), active ingredient: acetylene glycol surfactant, manufactured by Nissin Chemical Industry Co., Ltd. (1.0 part) and ion-exchanged water (26.6 parts) are mixed and room temperature is obtained using a magnetic stirrer. At 15 minutes to obtain a mixed solution.
Next, 25.7 parts of the aqueous dispersion of pigment-containing anionic polymer particles obtained in Production Example 19 (4.0 parts in terms of pigment content (in 100 parts of water-based ink)) was stirred with a magnetic stirrer. The above mixed solution was mixed, and further, 16.7 parts of an aqueous dispersion of polyester resin particles shown in Table 3 or Table 4 (5.0 parts in terms of solid content (in 100 parts of water-based ink)) was added dropwise with a dropper while stirring. did. Finally, the mixture was filtered with a filter having a pore diameter of 1.2 μm (product name: “Minisalto” (registered trademark), manufactured by Sartorius Stedim Biotech) to obtain a water-based ink. Table 5 shows the evaluation results of the obtained water-based ink.

  From the results of Table 5, it can be seen that the water-based inks of the examples are superior in adhesion to PVC, abrasion resistance and alcohol resistance as compared with the water-based inks of the comparative examples.

Example 6
Inkjet printer “IPSiO GX 2500” (Ricoh Co., Ltd., Piezo method) filled with water-based ink of Example 1 and cut to A4 size (Product name: “Transparent PVC RE-137”, Mimaki Engineering Co., Ltd.) A4 solid images were printed under the conditions of “Glossy paper, clean, no color matching”. After drying for 10 minutes in a dryer at 80 ° C. and standing for one day in an environmental room at room temperature of 25 ° C. and relative humidity of 50%, the sample was prepared and evaluated for adhesion, abrasion resistance and alcohol resistance. It was confirmed that the same performance as in the evaluation of Example 1 was exhibited.

Claims (7)

An aqueous ink for ink-jet recording containing a colorant and polyester resin particles (A),
An alcohol component in which the polyester constituting the polyester resin particles (A) contains an aliphatic diol having a hydroxy group bonded to a secondary carbon atom and having 3 to 6 carbon atoms in an amount of 45 mol% to 100 mol%; A water-based ink for inkjet recording, which is a polyester obtained by polycondensation with a carboxylic acid component containing 2 to 12 mol% of a polyvalent carboxylic acid having a valency or higher.   The aqueous ink for inkjet recording according to claim 1, wherein the aliphatic diol having a hydroxy group bonded to the secondary carbon atom has 3 or more and 4 or less carbon atoms.   The aqueous ink for inkjet recording according to claim 1 or 2, wherein the polyester has an ester group concentration of 6.0 mmol / g or more and 12.0 mmol / g or less.   The water-based ink for inkjet recording according to any one of claims 1 to 3, wherein the polyester resin particles (A) have a volume average particle diameter of 50 nm or more and 200 nm or less.   The water-based ink for inkjet recording according to any one of claims 1 to 4, wherein a content of the polyester resin particles (A) is 1% by mass or more and 15% by mass or less in the water-based ink. The manufacturing method of the water-based ink for inkjet recording in any one of Claims 1-5 which has following process (1)-(3).
Step (1): an alcohol component containing 45 to 100 mol% of an aliphatic diol having 3 to 6 carbon atoms and having a hydroxy group bonded to a secondary carbon atom, and a trivalent or higher polyvalent carboxylic acid A step of polycondensing a carboxylic acid component containing 2 mol% or more and 12 mol% or less to obtain a polyester Step (2): The polyester obtained in the step (1) is mixed with an aqueous medium to obtain polyester resin particles. Step of obtaining aqueous dispersion of (A) Step (3): The aqueous dispersion of polyester resin particles (A) obtained in Step (2) and an aqueous dispersion containing a colorant are mixed, and ink jet recording is performed. Process for obtaining water-based ink   An ink jet recording method comprising: attaching the water-based ink according to any one of claims 1 to 5 to a resin recording medium by an ink jet recording method; and then heating the resin recording medium to 40 ° C to 100 ° C.