JP6870889B2 - Water-based ink - Google Patents

Description

The present invention relates to water-based inks.

In fields such as commercial label printing used for product packaging printing and advertising, resin recording media such as polyethylene terephthalate, polyvinyl chloride, polyethylene, polypropylene, and nylon have conventionally been used with solvent-based inks and UV-curable inks. Printing has been done. On the other hand, from the viewpoints of reducing environmental load, energy saving, safety, etc., it is required to utilize an inkjet recording method, a flexographic printing method, and a gravure printing method as printing methods using water-based ink. In particular, the inkjet recording method is a recording method in which ink droplets are directly ejected from a very fine nozzle onto a recording member and adhered to obtain characters and images. Full-color printing is easy, inexpensive, and recording. It is widely used because it has many advantages that plain paper can be used as a member and that it does not come into contact with the printed matter. Therefore, an attempt is being made to utilize the inkjet recording method for resin recording media as well.

Patent Document 1 describes a water-based ink for inkjet recording containing pigment particles and polyester resin particles, wherein the pigment particles are a pigment and a polyester resin (A) in a mass ratio [pigment / polyester resin (A)] 55. Mass ratio of the pigment contained in the pigment particles to the total amount of the polyester resin (A) in the pigment particles and the polyester resin (B) constituting the polyester resin particles [pigment / polyester resin] (A + B)] is described as a water-based ink for inkjet recording, which is 10/90 to 40/60. It is described that the water-based ink is excellent in ink ejection property, image fixability on a recording medium, and glossiness of printed matter.

Patent Document 2 describes a polyester resin aqueous dispersion containing a polyester resin having an acid value of 8 mgKOH / g or more and a glass transition temperature of 40 to 120 ° C. The polyester resin contains isophthalic acid as a constituent acid component. It is characterized by containing 95 to 100 mol% of terephthalic acid and 1 to 5 mol% of trimellitic acid, and 25 to 80 mol% of an alkylene oxide derivative of bisphenol as a constituent alcohol component. Polyester resin aqueous dispersions are described. It is described that the dispersion is excellent in bending resistance as well as water resistance and solvent resistance of the obtained coating film.

Japanese Unexamined Patent Publication No. 2015-28114 Japanese Unexamined Patent Publication No. 2012-72308

When an image is formed on a recording medium made of polyester film by an inkjet recording method using a conventional water-based ink, the image density, the image fixability for preventing peeling of the image, and the image due to bending of the polyester film are obtained. There was room for improvement from the viewpoint of flexibility to prevent the occurrence of peeling or cracking.
The present invention relates to a water-based ink having excellent image density, image fixability, and flexibility.

The present invention is a water-based ink containing colorant particles and polyester resin particles.
A polycondensate of an alcohol component containing 70 mol% or more of an alkylene oxide adduct of bisphenol A and a carboxylic acid component containing 50 mol% or more of an aromatic dicarboxylic acid, in which the colorant particles and the polyester resin particles are the same or different, respectively. The present invention relates to a water-based ink containing the polyester resin A and having a softening point of the polyester resin A of 125 ° C. or higher and 160 ° C. or lower.

According to the present invention, it is possible to provide a water-based ink having excellent image density, image fixability, and flexibility.

[Water-based ink]
The water-based ink of the present invention contains colorant particles and polyester resin particles.
The colorant particles and the polyester resin particles are polycondensations of an alcohol component containing 70 mol% or more of an alkylene oxide adduct of bisphenol A and a carboxylic acid component containing 50 mol% or more of an aromatic dicarboxylic acid, which are the same or different from each other. The polyester resin A is contained, and the softening point of the polyester resin A is 125 ° C. or higher and 160 ° C. or lower.
In addition, in this specification, "water-based ink" means an ink in which 40% by mass or more is water in a liquid medium.
The water-based ink is excellent in image density, image fixability, and flexibility.

The reason why the above-mentioned water-based ink exerts such an effect is not clear, but it is considered as follows.
Both the colorant particles and the polyester resin particles contained in the water-based ink have high compatibility because they contain the polyester resin A, and because they have a relatively high softening point, they are plasticized with respect to the solvent in the water-based ink. It is considered that the image density is increased because it is possible to form a smooth ink film that is less likely to aggregate and the stability is improved.
The pigment particles and polyester resin particles contained in the water-based ink have a rigid skeleton derived from the alkyleneoxy adduct of bisphenol A and the aromatic ring of the aromatic dicarboxylic acid, so that the aqueous medium immediately after printing is not completely dried. Even if it is present, it is considered that it is excellent in initial fixing because it is possible to form a strong film, and it is also excellent in flexibility because the coating film strength after drying is high.

<Polyester resin particles>
The polyester resin particles include the polyester resin A from the viewpoints of image density, image fixability, and flexibility.
[Polyester resin A]
The polyester resin A is obtained by polycondensing an alcohol component and a carboxylic acid component, that is, a polycondensate product of an alcohol component and a carboxylic acid component.
The polyester resin A preferably has a crosslinked structure from the viewpoint of further improving image density, image fixability, and flexibility.
Here, the crosslinked structure means a structure in which a plurality of branching units are introduced in the polyester chain. The crosslinked structure can be introduced by containing a trihydric or higher polyhydric alcohol as an alcohol component or by containing a trivalent or higher valent carboxylic acid as an acid component. Among these, it is preferable to contain a polyvalent carboxylic acid having a valence of 3 or more as an acid component.

≪Alcohol component≫
The alcohol component contains 70 mol% or more of the alkylene oxide adduct of bisphenol A from the viewpoint of image density, image fixability, and flexibility.
The content of the alkylene oxide adduct of bisphenol A is preferably 80 mol% or more, more preferably 85 mol% or more, still more preferably 85 mol% or more in the alcohol component from the viewpoint of further improving the image density, image fixability, and flexibility. Is 90 mol% or more and 100 mol% or less, and preferably 100 mol%.
The alkylene oxide adduct of bisphenol A is preferably a compound represented by the following general formula (I).

In the general formula (I), OR ¹ and R ² O are both alkyleneoxy groups, preferably alkyleneoxy groups having 1 or more and 4 or less carbon atoms independently, and more preferably ethyleneoxy groups. Or it is a propyleneoxy group.
x and y correspond to the number of moles of alkylene oxide added. Further, from the viewpoint of reactivity with the carboxylic acid component, the average value of the sum of x and y is preferably 2 or more, and preferably 7 or less, more preferably 5 or less, still more preferably 3 or less. ..
Further, x OR ¹ and y R ² O may be the same or different, but are preferably the same. The alkylene oxide adduct of bisphenol A may be used alone or in combination of two or more. Among these, a propylene oxide adduct of bisphenol A and an ethylene oxide adduct of bisphenol A are preferable.

The alcohol component may contain an alcohol component other than the alkylene oxide adduct of bisphenol A.
Examples of other alcohol components include diols other than the alkylene oxide adduct of bisphenol A, trihydric or higher polyhydric alcohols, and the like.
Examples of the diol include an aliphatic diol having 2 to 12 carbon atoms in the main chain, an aromatic diol other than the alkylene oxide adduct of bisphenol A (hereinafter, also referred to as “another aromatic diol”), and an alicyclic diol. Can be mentioned.

Examples of the aliphatic diol include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol, 1,8-octanediol, and 1,9-. Examples thereof include nonanediol, 1,10-decanediol, and 1,12-dodecanediol.
The aliphatic diol is preferably an aliphatic diol having a hydroxy group bonded to a secondary carbon atom and having 3 to 6 carbon atoms.
Examples of the aliphatic diol having a hydroxy group bonded to a secondary carbon atom and having 3 or more and 6 or less carbon atoms include 1,2-propanediol, 1,2-butanediol, 1,3-butanediol, and 2, 3-butanediol, 1,2-pentanediol, 1,4-pentanediol, 2,4-pentanediol, 1,2-hexanediol, 1,5-hexanediol, 2,5-hexanediol, 3,3 Included is -dimethyl-1,2-butanediol. Among these, 1,2-propanediol and 2,3-butanediol are preferable, and 1,2-propanediol is more preferable.
The content of the aliphatic diol having 2 or more and 12 or less carbon atoms in the main chain is preferably 30 mol% or less, more preferably 25 mol% or less, still more preferably 10 mol% or less, and preferably 10 mol% or less in the alcohol component. It is 0 mol%.

Other aromatic diols include divalent phenols such as hydroquinone, alkylene oxide adducts such as bisphenol F (4,4'-dihydroxydiphenylmethane) and bisphenol S (4,4'-dihydroxydiphenylsulfone).
The content of the other aromatic diol is preferably 30 mol% or less, more preferably 25 mol% or less, more preferably 10 mol% or less, and preferably 0 mol% or less.

Examples of the alicyclic diol include cyclohexanediol, hydrogenated bisphenol A, and cyclohexanedimethanol.
The content of the alicyclic diol is preferably 1 mol% or more, more preferably 2 mol% or more, and preferably 30 mol% or less, more preferably 25 mol% or less in the alcohol component. The alcohol component may be used alone or in combination of two or more.

≪Carboxylic acid component≫
The carboxylic acid component contains 50 mol% or more of aromatic dicarboxylic acid from the viewpoint of image density, image fixability, and flexibility.
The carboxylic acid component includes not only carboxylic acids but also their anhydrides and alkyl esters having 1 or more and 3 or less carbon atoms. That is, in the present specification, when only the name of the carboxylic acid is described, it is assumed that the anhydride of the carboxylic acid and the alkyl ester having 1 to 3 carbon atoms are also described.
The content of the aromatic dicarboxylic acid is preferably 55 mol% or more, more preferably 60 mol% or more, still more preferably 70 in the carboxylic acid component from the viewpoint of further improving the image density, image fixability, and flexibility. It is mol% or more and 100 mol% or less, preferably 95 mol% or less, more preferably 90 mol% or less.
Examples of the aromatic dicarboxylic acid include phthalic acid, isophthalic acid, and terephthalic acid. Of these, terephthalic acid is preferable.

The carboxylic acid component may contain a carboxylic acid component other than the aromatic dicarboxylic acid.
Examples of other carboxylic acid components include aliphatic dicarboxylic acids, alicyclic dicarboxylic acids, and trivalent or higher polyvalent carboxylic acids.

The aliphatic dicarboxylic acid was substituted with, for example, fumaric acid, adipic acid, sebacic acid, maleic acid, azelaic acid, succinic acid, an alkyl group having 1 to 20 carbon atoms or an alkenyl group having 2 to 20 carbon atoms. Examples include succinic acid. 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, and octenyl succinic acid. Of these, fumaric acid is preferable.
The content of the aliphatic dicarboxylic acid is preferably 1 mol% or more, more preferably 2 mol% or more, and preferably 40 mol% or less, more preferably 30 mol% or less, still more preferably 30 mol% or less, in the carboxylic acid component. Is 20 mol% or less, more preferably 10 mol% or less.

Examples of the alicyclic dicarboxylic acid include cyclohexanedicarboxylic acid.
The content of the alicyclic dicarboxylic acid is preferably 40 mol% or less, more preferably 30 mol% or less, still more preferably 20 mol% or less, still more preferably 10 mol% or less, and more preferably 10 mol% or less in the carboxylic acid component. It is preferably 0 mol%.

The carboxylic acid component preferably contains a trivalent or higher valent carboxylic acid from the viewpoint of introducing a crosslinked structure into the polyester resin A to further improve image density, image fixability, and flexibility.
As the trivalent or higher polyvalent carboxylic acid, a trivalent or higher polyvalent aromatic carboxylic acid is preferable, and a trivalent aromatic carboxylic acid is more preferable, from the viewpoint of further improving image density, image fixability, and flexibility. preferable.
The trivalent or higher valent aromatic carboxylic acid has preferably 8 or more carbon atoms, more preferably 9 or more carbon atoms, and preferably 16 or less, more preferably 14 or less carbon atoms.
Examples of the trivalent or higher polyvalent carboxylic acid include trimellitic acid, 2,5,7-naphthalene tricarboxylic acid, pyromellitic acid and the like.
Among these, trimellitic acid or an anhydride thereof is preferable, and trimellitic acid anhydride is more preferable.
The content of the trivalent or higher polyvalent carboxylic acid is preferably 7 mol% or more, more preferably 10 mol% or more, from the viewpoint of further improving the image concentration, image fixability, and flexibility in the carboxylic acid component. It is more preferably 15 mol% or more, and preferably 45 mol% or less, more preferably 30 mol% or less, still more preferably 25 mol% or less, still more preferably 20 mol% or less.
The carboxylic acid component may be used alone or in combination of two or more.

The equivalent ratio (COOH group / OH group) of the carboxy group (COOH group) of the carboxylic acid component to the hydroxy group (OH group) of the alcohol component in the polyester resin A further improves the image density, image fixability, and flexibility. From the viewpoint of making it, it is preferably 0.65 or more, more preferably 0.80 or more, and preferably 1.2 or less, more preferably 1.1 or less.

[Manufacturing method of polyester resin A]
The polyester resin A can be produced by subjecting a carboxylic acid component and an alcohol component to a polycondensation reaction. For example, it can be produced by polycondensing an alcohol component and a carboxylic acid component in an inert gas atmosphere at a temperature of 120 ° C. or higher and 250 ° C. or lower, if necessary, using an esterification catalyst and a polymerization inhibitor. it can.
Examples of the esterification catalyst include tin compounds such as dibutyltin oxide and di (2-ethylhexanoic acid) tin, and titanium compounds such as titanium diisopropyrate bistriethanolaminate.
The amount of the esterification catalyst used is preferably 0.01 part by mass or more, more preferably 0.1 part by mass or more, and preferably 1 part by mass with respect to 100 parts by mass of the total amount of the carboxylic acid component and the alcohol component. It is 5.5 parts by mass or less, more preferably 1.0 parts by mass or less.
In addition, a radical polymerization inhibitor can be used if necessary. Examples of the radical polymerization inhibitor include 4-tert-butylcatechol. The amount of the radical polymerization inhibitor used is preferably 0.01 part by mass or more, more preferably 0.05 part by mass or more, and preferably 0.05 part by mass or more, based on 100 parts by mass of the total amount of the carboxylic acid component and the alcohol component. It is 0.5 parts by mass or less, more preferably 0.1 parts by mass or less.

[Physical characteristics of polyester resin A]
The softening point of the polyester resin A is 125 ° C. or higher and 160 ° C. or lower from the viewpoint of image density, image fixability, and flexibility, and is preferably from the viewpoint of further improving image density, image fixability, and flexibility. It is 130 ° C. or higher, more preferably 135 ° C. or higher, further preferably 140 ° C. or higher, and preferably 158 ° C. or lower, more preferably 150 ° C. or lower.
The means for adjusting within the above range is not particularly limited, but for example, it can be appropriately adjusted depending on the type and ratio of the raw material monomer, and the production conditions such as reaction temperature, reaction time, and cooling rate.

The glass transition temperature of the polyester resin A is preferably 40 ° C. or higher, more preferably 60 ° C. or higher, still more preferably 70 ° C. or higher, still more preferably 75 ° C. or higher, from the viewpoint of further improving image density, image fixability, and flexibility. It is ℃ or more, and preferably 100 ℃ or less, more preferably 90 ℃ or less, still more preferably 85 ℃ or less, still more preferably 80 ℃ or less.

The acid value of the polyester resin A is preferably 5 mgKOH / g or more, more preferably 10 mgKOH / g or more, still more preferably 15 mgKOH / g or more, from the viewpoint of further improving image density, image fixability, and flexibility. Then, it is preferably 40 mgKOH / g or less, more preferably 30 mgKOH / g or less, and further preferably 25 mgKOH / g or less.

The hydroxyl value of the polyester resin A is preferably 5 mgKOH / g or more, more preferably 10 mgKOH / g or more, still more preferably 12 mgKOH / g or more, still more preferably 12 mgKOH / g or more, from the viewpoint of further improving image density, image fixability, and flexibility. Is 15 mgKOH / g or more, and preferably 80 mgKOH / g or less, more preferably 60 mgKOH / g or less, still more preferably 40 mgKOH / g or less, still more preferably 30 mgKOH / g or less.

The softening point, glass transition temperature, acid value, and hydroxyl value of the polyester resin are values obtained by the method described in Examples for the polyester resin as a raw material thereof. When two or more kinds of polyester resins are mixed and used, the softening point, the glass transition temperature, the acid value, and the hydroxyl value are obtained as a mixture of two or more kinds of polyester resins by the method described in Examples. It is the value that was given.
The glass transition temperature, acid value, and hydroxyl value of the polyester resin are all desired by appropriately adjusting the type of monomer used in the production of the polyester resin, the blending ratio, the polycondensation temperature, and the reaction time. be able to.

[Manufacturing method of polyester resin particles]
The polyester resin particles are preferably produced by a method in which a resin containing the polyester resin A is dispersed in an aqueous medium to obtain a dispersion liquid of the polyester resin particles.
As the aqueous medium, a medium containing water as a main component is preferable. The content of water in the aqueous medium is preferably 80% by mass or more, more preferably 90% by mass or more, and 100% from the viewpoint of improving the dispersion stability of the resin particle dispersion liquid and from the viewpoint of environmental safety. It is less than or equal to mass%, and more preferably 100% by mass. As the water, deionized water, ion-exchanged 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 such as ether solvents such as tetrahydrofuran.

As a method for obtaining a dispersion liquid of the polyester resin particles, a method of adding a resin containing the polyester resin A to an aqueous medium and performing a dispersion treatment by a disperser or the like, or a method of gradually adding the aqueous medium to the resin containing the polyester resin and transferring the resin. Examples thereof include a method of emulsifying the resin. Among these, the method by phase inversion emulsification is preferable.
As a phase inversion emulsification method, it is preferable to first dissolve a resin containing a polyester resin in an organic solvent, then add an aqueous medium to this solution to invert the phase, and then remove the organic solvent. Hereinafter, the phase inversion emulsification method will be described.

[Phase inversion emulsification method]
First, the resin containing the polyester resin A is dissolved in an organic solvent to obtain a solution containing the polyester resin.
When a plurality of types of polyester resin A or resins other than polyester resin A are contained, a mixture of these polyester resin A and other resins may be used in advance, but these resins are simultaneously added to the organic solvent. And dissolve it to obtain a solution containing the polyester resin A.
As a method for obtaining a solution containing the polyester resin A, a method in which a resin containing the polyester resin A and an organic solvent are placed in a container to dissolve them, 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 resin containing the polyester resin A in an organic solvent and the subsequent addition of the basic aqueous solution are usually carried out at a temperature equal to or lower than the boiling point of the organic solvent.
As the organic solvent, a dialkyl ketone having an alkyl group having 1 to 3 carbon atoms such as acetone and methyl ethyl ketone is preferable, and methyl ethyl ketone is preferable, from the viewpoint that the resin containing the polyester resin A is dissolved and can be easily removed from the emulsion. More preferred.

The mass ratio of the organic solvent to the resin containing the polyester resin A [organic solvent / resin] is from the viewpoint of dissolving the resin and facilitating the phase inversion to the aqueous medium, and from the viewpoint of further improving the dispersion stability of the resin particle dispersion liquid. Therefore, it is preferably 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. Below, it is more preferably 150/100 or less.

Further, from the viewpoint of improving the affinity of the resin containing the polyester resin A for an aqueous medium and further improving the dispersion stability of the resin particle dispersion liquid, it is possible to neutralize the acid groups in the resin with a basic compound. preferable.
Examples of the basic compound include alkanolamines such as sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, sodium hydrogencarbonate, potassium hydrogencarbonate, ammonia and diethylethanolamine.
The equivalent amount (mol%) of the basic compound to be used with respect to the acid group of the resin is preferably 10 mol% or more, more preferably 30 mol% or more, still more preferably 50 mol, from the viewpoint of further improving the dispersion stability of the resin particles. % Or more, and preferably 150 mol% or less, more preferably 120 mol% or less, still more preferably 100 mol% or less.
The equivalent amount (mol%) of the basic compound used can be calculated by the following formula. When the equivalent amount of the basic compound used is 100 mol% or less, it is synonymous with the degree of neutralization, and when the equivalent amount of the neutralizing agent used exceeds 100 mol% in the following formula, the neutralizing agent is the acid group of the resin. The degree of neutralization of the resin at this time is considered to be 100 mol%.
Equivalent to use of basic compound (mol%) = [{additional mass of basic compound (g) / equivalent of basic compound} / [{acid value of resin (mgKOH / g) x mass of resin (g)} / (56 x 1000)]] x 100

Next, an aqueous medium is added to the solution containing the resin, and the phase is inverted to obtain an aqueous dispersion of resin particles containing the polyester resin A.
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 25 ° C. or higher, from the viewpoint of further improving the dispersion stability of the resin particle dispersion liquid. Is 80 ° C. or lower, more preferably 75 ° C. or lower.

From the viewpoint of further improving the dispersion stability of the resin particle dispersion liquid, the addition rate of the aqueous medium is preferably 0.5 part by mass with respect to 100 parts by mass of the resin constituting the resin particles until the phase inversion is completed. / Minute or more, more preferably 1 part by mass or more, still more preferably 3 parts by mass or more, still more preferably 5 parts by mass or more, and preferably 100 parts by mass or less, more preferably 100 parts by mass or more. It is 50 parts by mass or less, more preferably 20 parts by mass or less, still more preferably 15 parts by mass or less. There is no limit to the rate of addition of the aqueous medium after the phase inversion and after the resin particles are obtained.
The amount of the aqueous medium added is preferably 50 parts by mass or more, more preferably 100 parts by mass or more, still more preferably 100 parts by mass or more, based on 100 parts by mass of the resin constituting the resin particles, from the viewpoint of further improving the productivity of the aqueous dispersion. Is 150 parts by mass or more, and preferably 900 parts by mass or less, more preferably 500 parts by mass or less, still more preferably 400 parts by mass or less.

After the phase inversion emulsification, if necessary, the organic solvent may be removed from the dispersion obtained by the phase inversion emulsification. The method for removing the organic solvent is not particularly limited, and any method can be used, but distillation is preferable because it is dissolved in water.
The aqueous dispersion of the polyester resin particles thus obtained is preferably filtered through a wire mesh or the like to remove coarse particles or the like. Further, when the organic solvent is removed, water is azeotropically reduced together with the organic solvent, so it is preferable to add water to adjust the solid content concentration.

The solid content concentration of the aqueous dispersion of the polyester resin particles is preferably 5% by mass or more, more preferably 10% by mass or more, still more preferably 20% by mass or more, still more preferably 25% by mass or more, and preferably. It is 50% by mass or less, more preferably 45% by mass or less, still more preferably 40% by mass or less, still more preferably 35% by mass or less.
The pH of the aqueous dispersion of the polyester resin particles is preferably 6.0 or more, more preferably 6.5 or more, still more preferably 6.8 or more, and preferably 9.0 or less, more preferably 8. It is 0 or less, more preferably 7.5 or less.

The content of the polyester resin A in the polyester resin particles is preferably 70% by mass or more, more preferably 80% by mass or more, still more preferably 90% by mass or more, and 100% by mass or less, and preferably. Is 100% by mass.
The content of the polyester resin particles in the water-based ink is preferably 1% by mass or more, more preferably 2% by mass or more, further preferably 3% by mass or more, and preferably 20% by mass or less, more preferably 15% by mass or more. It is mass% or less, more preferably 10 mass% or less.

<Colorant particles>
The colorant particles contain the polyester resin A from the viewpoint of image density, image fixability, and flexibility.
As the polyester resin A, the polyester resin A exemplified by the polyester resin particles described above is preferably used. In the polyester resin particles A of the colorant particles, the alcohol component, the carboxylic acid component, and other physical properties in the same range as those of the polyester resin particles described above are preferable examples.

The colorant particles and the polyester resin particles contain the same or different polyester resin A, respectively. That is, the polyester resin A used for the colorant particles may be the same as or different from the polyester resin A used for the polyester resin particles.
From the viewpoint of further improving image density, image fixability, and flexibility, the content of the alkylene oxide adduct of bisphenol A in the alcohol component of the polyester resin A contained in the colorant particles Al _c (mol%) and polyester. The content of the alkylene oxide adduct of bisphenol A in the alcohol component of the polyester resin A contained in the resin particles All _r (mol%) preferably satisfies the following relational expression (1).
｜ Al _{c −} Al _r ｜ ≦ 30 (1)
| Al _{c −} Al _r | is preferably 25 or less, more preferably 10 or less, still more preferably 5 or less, and 0 or more, from the viewpoint of further improving image density, image fixability, and flexibility. Yes, and preferably 0.

From the viewpoint of further improving image density, image fixability, and flexibility, the content of aromatic dicarboxylic acid in the carboxylic acid component of the polyester resin A contained in the colorant particles Ca _c (mol%) and the polyester resin particles. a content of the aromatic dicarboxylic acid in the carboxylic acid component of the polyester resin a Ca r _(mol%) contained in it, preferably satisfy the following relational expression (2).
_{| Ca c -Ca r | ≦ 30} (2)
| _Ca c -Ca _r |, the image density, image fixability, and from the viewpoint of further improving the flexibility, preferably 25 or less, more preferably 10 or less, more preferably 5 or less, and, greater than 0 Yes, and preferably 0.

Image density, image fixability, and from the viewpoint of further improving the flexibility, the softening point Tm c of the polyester resin A contained in the colorant particles _(° C.), a softening point Tm _r of the polyester resin A contained in the polyester resin particles (° C.) preferably satisfies the following relational expression (3).
｜ Tm _{c − Tm r} ｜ ≦ 30 (3)
| _Ca c -Ca _r |, the image density, image fixability, and from the viewpoint of further improving the flexibility, preferably 20 or less, more preferably 12 or less, more preferably 5 or less, and, greater than 0 Yes, and preferably 0.

[Colorant]
The colorant may be either a pigment or a dye.
Examples of the colorant include pigments, hydrophobic dyes, water-soluble dyes (acid dyes, reactive dyes, direct dyes, etc.) and the like. Among these, pigments and hydrophobic dyes are preferable, and pigments are more preferable.

The pigment may be either an inorganic pigment or an organic pigment. In addition, if necessary, they can be used in combination with extender pigments.
Examples of the inorganic pigment include carbon black and metal oxides. For black ink, carbon black is preferable.
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.
As the organic pigment, 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 product numbers selected from the group consisting of pigment greens can be mentioned.

The hydrophobic dye means a dye having a solubility in 100 g of water (20 ° C.) of preferably less than 6% by mass. Examples of the hydrophobic dye include oil-soluble dyes and disperse dyes.
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 product numbers selected from the group consisting of solvent oranges are listed, and are commercially available from Orient Chemical Industries Co., Ltd., BASF Corporation, and the like.
The above dyes can be used alone or in admixture of two or more at any ratio.
As the colorant, one type can be used alone or two or more types can be mixed and used at an arbitrary ratio.

(Manufacturing method of colorant particles)
The colorant particles are obtained by dispersing and treating a mixture containing, for example, polyester resin A, an organic solvent, a colorant, water, and a neutralizer, a surfactant, etc., if necessary, to form the colorant particles of the polymer particles containing the colorant. After obtaining the dispersion, the organic solvent can be removed from the dispersion to obtain an aqueous dispersion of colorant particles containing the polyester resin A.

As the organic solvent, the above-mentioned organic solvent can be used.
The acid group of the polyester resin A may be neutralized with a basic compound.

There is no particular limitation on the dispersion method of the dispersion. It is preferable to control _{the volume average particle size (DV} ) of the polymer particles containing the colorant to a desired particle size by using a known kneader, disperser or the like. An aqueous dispersion of colorant particles can be obtained by removing the organic solvent from the obtained dispersion by a known method.
The aqueous dispersion of the colorant particles is preferably filtered through a wire mesh or the like to remove coarse particles or the like. The colorant particles may be crosslinked, or various additives such as an organic solvent, a preservative, and a fungicide, which are optionally added to the water-based ink described later, may be added to the water-based dispersion of the colorant particles. ..

The volume average particle size ( _DV ) of the colorant particles is preferably 40 nm or more, more preferably 50 nm or more, and preferably 200 nm or less, more preferably 150 nm or less, from the viewpoint of improving the image density of the ink. is there.
The volume average particle diameter ( _DV ) of the colorant particles is measured by a dynamic light scattering method, and specifically, it is measured by the method of Examples.

The solid content concentration of the aqueous dispersion of the colorant particles is preferably 5% by mass or more, more preferably 10% by mass or more, further preferably 15% by mass or more, and preferably 50% by mass or less, more preferably 50% by mass or less. It is 45% by mass or less, more preferably 40% by mass or less, still more preferably 35% by mass or less.

The mass ratio of the colorant to the polyester resin A [colorant / polyester resin A] is preferably 40/60 or more, more preferably 50/50 or more, still more preferably 60/40 or more, and preferably 90/60 or more. It is 10 or less, more preferably 80/20 or less, still more preferably 75/25 or less.
The content of the colorant particles in the water-based ink is preferably 2% by mass or more, more preferably 3% by mass or more, further preferably 5% by mass or more, and preferably 20% by mass or less, more preferably 15% by mass. It is mass% or less, more preferably 10 mass% or less.
The content of the colorant in the water-based ink is preferably 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 15% by mass. % Or less, more preferably 10% by mass or less.

The mass ratio of the colorant particles to the polyester resin particles [colorant particles / polyester resin particles] is preferably 10/90 or more in the water-based ink from the viewpoint of further improving the image density, image fixability, and flexibility. It is preferably 20/80 or more, more preferably 25/75 or more, and preferably 80/20 or less, more preferably 70/30 or less, still more preferably 60/40 or less, still more preferably 55/45 or less. is there.

[Other components of water-based ink]
Water-based inks include, for example, organic solvents, penetrants, dispersants, surfactants, viscosity regulators, defoamers, preservatives, fungicides, rust inhibitors, pH regulators, antioxidants, UV absorbers, etc. May contain various additives of.
Examples of the organic solvent include polyhydric alcohols, polyhydric alcohol alkyl ethers, polyhydric alcohol aryl ethers, cyclic carbonates, nitrogen-containing heterocyclic compounds, amides, amines, and sulfur-containing compounds.

Examples of the polyhydric alcohol include ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, polypropylene glycol, 1,3-propanediol, 1,2-butanediol, and 1, 3-butanediol, 2,3-butanediol, 1,4-butanediol, 3-methyl-1,3-butanediol, 1,5-pentanediol, 1,2-hexanediol, 1,6-hexanediol , 2-Methyl-2,4-pentanediol, tetraethylene glycol, glycerin, 1,2,6-hexanetriol, 1,2,4-butanediol, 1,2,3-butanetriol, 3-methyl-1 , 3,5-Pentanetriol, 2-ethyl-1,3-hexanediol, 2,2,4-trimethyl-1,3-pentanediol.
Examples of the polyhydric alcohol alkyl ether include ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, triethylene glycol monomethyl ether, triethylene glycol monoisobutyl ether, and tetraethylene glycol. Examples thereof include monomethyl ether, propylene glycol monoethyl ether, dipropylene glycol monobutyl ether, dipropylene glycol monomethyl ether, tripropylene glycol monomethyl ether, and tripropylene glycol monobutyl ether.

Examples of the polyhydric alcohol aryl ether include ethylene glycol monophenyl ether and ethylene glycol monobenzyl ether.
Examples of the cyclic carbonate include ethylene carbonate and propylene carbonate.
Examples of the nitrogen-containing heterocyclic compound include N-methyl-2-pyrrolidone, N-hydroxyethyl-2-pyrrolidone, 1,3-dimethylimidazolidinone, and ε-caprolactam.
Examples of the amide include formamide, N-methylformamide, and N, N-dimethylformamide.
Examples of amines include monoethanolamine, diethanolamine, triethanolamine, monoethylamine, diethylamine, and triethylamine.
Examples of the sulfur-containing compound include dimethyl sulfoxide, sulfolane, thiodiethanol, and thiodiglycol.
As the organic solvent, one type may be used alone or two or more types may be used in combination, but it is preferable to use two or more types in combination.
Among these, at least one or more selected from polyhydric alcohols, polyhydric alcohol alkyl ethers, and nitrogen-containing heterocyclic compounds are preferable, and diethylene glycol, propylene glycol, dipropylene glycol, 1,2-butanediol, and 1 , 2-Hexanediol, glycerin, diethylene glycol monomethyl ether, dipropylene glycol monomethyl ether, and one or more selected from 2-pyrrolidone are more preferable.

The content of the organic solvent in the water-based ink is preferably 5% by mass or more, more preferably 10% by mass or more, and preferably 40% by mass or less, more preferably 35% by mass or less.

Examples of the surfactant include nonionic surfactants, anionic surfactants, amphoteric surfactants, silicone-based surfactants, and fluorine-based surfactants.
Examples of the nonionic surfactant include glycol ethers such as polyoxyethylene alkyl ethers, acetylene glycols or polyoxyalkylene adducts thereof, polyoxyethylene alkyl phenyl ethers, polyoxyethylene alkyl esters, and polyoxyethylene sorbitan fatty acid esters. Can be mentioned.
Examples of the anionic surfactant include salts of polyoxyethylene alkyl ether acetate, dodecylbenzene sulfonate, amber acid ester sulfonate, lauryl salt, and polyoxyethylene alkyl ether sulfate.
Examples of amphoteric surfactants include laurylaminopropionate, lauryldimethylbetaine, stearyldimethylbetaine, lauryldihydroxyethylbetaine, lauryldimethylamine oxide, myristyldimethylamine oxide, stearyldimethylamine oxide, and dihydroxyethyllaurylamine oxide. Be.

Examples of the silicone-based surfactant include polyester-modified silicone and polyether-modified silicone.
Examples of the fluorine-based surfactant include a perfluoroalkyl sulfonic acid compound, a perfluoroalkyl carboxylic acid compound, a perfluoroalkyl phosphoric acid ester compound, and a perfluoroalkyl ethylene oxide adduct.
The surfactant may be used alone or in combination of two or more.
Among these, at least one selected from nonionic surfactants and silicone-based surfactants is preferable, and at least one selected from glycol ethers, acetylene glycols or polyoxyalkylene adducts thereof, polyester-modified silicones, and polyether-modified silicones. One is more preferred, and at least one selected from glycol ethers and acetylene glycols or polyoxyalkylene adducts thereof is even more preferred, and at least one selected from acetylene glycols or polyoxyalkylene adducts thereof and polyoxyethylene alkyl ethers. One is more preferable.

The content of the surfactant in the water-based ink is preferably 0.1% by mass or more, more preferably 0.3% by mass or more, and preferably 5% by mass or less, more preferably 2% by mass or less. is there.

Examples of the defoaming agent include silicone-based defoaming agents, polyether-based defoaming agents, and fatty acid ester-based defoaming agents.
Examples of preservatives and fungicides include 1,2-benzisothiazolin-3-one, sodium dehydroacetate, sodium sorbate, 2-pyridinethiol-1-oxide sodium, sodium benzoate, and sodium pentachlorophenol. Be done.
Examples of the rust preventive include acidic sulfite, sodium thiosulfate, ammon thiodiglycolate, diisopropylammonium nitrite, and pentaerythritol tetranitrate.

The pH adjuster is not particularly limited as long as it can adjust the pH to 7 or more without adversely affecting the ink to be prepared, and any substance can be used depending on the purpose. For example, diethanolamine, etc. Amines such as triethanolamine; hydroxides of alkali metals such as lithium hydroxide, sodium hydroxide and potassium hydroxide; alkali metal carbonates such as lithium carbonate, sodium carbonate and potassium carbonate; ammonium hydroxide, quaternary Ammonia hydroxide can be mentioned.
Examples of the antioxidant include a phenol-based antioxidant (including a hindered phenol-based antioxidant), an amine-based antioxidant, a sulfur-based antioxidant, and a phosphorus-based antioxidant.
Examples of the ultraviolet absorber include a benzophenone-based ultraviolet absorber, a benzotriazole-based ultraviolet absorber, and a salicylate-based ultraviolet absorber.

The content of water in the liquid medium of the water-based ink is preferably 45% by mass or more, more preferably 50% by mass or more, still more preferably 55% by mass or more, and preferably 95% by mass or less, more preferably 95% by mass or less. It is 90% by mass or less, more preferably 80% by mass or less.
The content of water contained in the water-based ink is preferably 30% by mass or more, more preferably 40% by mass or more, still more preferably 50% by mass or more, still more preferably 50% by mass or more in the water-based ink from the viewpoint of maintaining the viscosity of the ink appropriately. Is 55% by mass or more, and preferably 90% by mass or less, more preferably 80% by mass or less, still more preferably 75% by mass or less.

[Manufacturing method of water-based ink]
The water-based ink can be obtained, for example, by mixing an water-based dispersion of resin particles and an water-based dispersion containing a colorant.
Here, at least one of the above-mentioned optional components may be further mixed. For mixing, for example, various stirring devices can be used.
The preferred contents of the resin particles, the colorant, and the water in the water-based ink are as described above.

[Inkjet recording method]
The water-based ink can be used as an ink for inkjet recording. As a preferred embodiment when the water-based ink is used in the inkjet recording method, for example, after the water-based ink is attached to the resin recording medium by the inkjet recording method, the resin recording medium to which the water-based ink is attached is placed at 40 ° C. or higher to 120. Heat below ° C.

Water-based inks can be used for both office printing and commercial and industrial printing of catalogs, leaflets, packages, labels and the like. Suitable for non-water-absorbing or low-water-absorbing resin recording media such as PET (polyethylene terephthalate), PVC (polyvinyl chloride), PP (polypropylene), NY (nylon), which are suitable for commercial and industrial label printing. Since it can be used, it is suitable for use in commercial or industrial printing.
In the present invention, "non-water absorption or low water absorption" means that the amount of water absorption of the recording medium at a contact time of 100 msec between the recording medium and water is 0 g / m ² or more and 10 g / m ² or less. To do.

The resin recording medium is preferably at least one selected from a polyethylene terephthalate film, a polyvinyl chloride film, a polypropylene film and a nylon film, and more preferably at least one selected from a polyethylene terephthalate film and a nylon film. As the resin recording medium, a corona-treated base material may be used.
Examples of commercially available resin films include "Lumirror T60" (manufactured by Toray Co., Ltd., polyethylene terephthalate), "PVC80BP" (manufactured by Lintec Co., Ltd., vinyl chloride), and "DGS-210WH" (manufactured by Roland DG Co., Ltd.). , Vinyl chloride), "Transparent PVC RE-137" (Mimaki Engineering Co., Ltd., vinyl chloride), "Kainas KEE70CA" (Lintech Co., Ltd., polyethylene), "Yupo SG90 PAT1" (Lintech Co., Ltd., polypropylene), "FOR", "FOA" (above, polypropylene made by Futamura Chemical Co., Ltd.), "Bonil RX" (made by Kojin Film & Chemicals Co., Ltd., nylon), "Emblem ONBC" (made by Unitika Co., Ltd., nylon) Be done.

As the inkjet recording method, a known inkjet recording device can be used. Examples of the inkjet recording device include a thermal inkjet recording device and a piezo inkjet recording device. The water-based ink is more preferably used as a piezo-type water-based ink for inkjet recording.
The heating temperature of the resin recording medium is preferably 50 ° C. or higher, more preferably 60 ° C. or higher, and preferably 110 ° C. or lower, more preferably 110 ° C. or lower, from the viewpoint of obtaining excellent adhesion to various resin recording media. It is 100 ° C. or lower.

In this example, various physical properties were measured as follows and evaluated as follows.

[Measuring method]
[Acid value and hydroxyl value of polyester resin]
Measure according to JIS K0070. However, the solvent specified in JIS K0070 is 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 resin]
Using a flow tester "CFT-500D" (manufactured by Shimadzu Corporation), while heating a 1 g sample at a heating rate of 6 ° C./min, a load of 1.96 MPa was applied by a plunger, and the diameter was 1 mm and the length was 1 mm. Push out from the nozzle. The amount of plunger drop of the flow tester is plotted against the temperature, and the temperature at which half of the sample flows out is used as the softening point.

[Glass transition temperature of polyester resin]
Using a differential scanning calorimeter "Q-100" (manufactured by TA Instruments Japan Co., Ltd.), weigh 0.01 to 0.02 g of the sample in an aluminum pan, raise the temperature to 200 ° C, and then start from 200 ° C. A sample for measurement is prepared by cooling to 0 ° C. at a temperature lowering rate of 10 ° C./min. After that, the temperature is raised at a temperature rising rate of 10 ° C./min, and the temperature at the intersection of the extension line of the baseline below the maximum endothermic peak temperature and the tangent line showing the maximum slope from the rising portion of the peak to the peak peak is transferred to the glass. Let it be the temperature.

[Volume average particle size of resin particles ( _Dv )]
(1) Measuring device: Zeta potential / particle size measuring system "ELSZ-2" (manufactured by Otsuka Electronics Co., Ltd.)
(2) Measurement conditions: Cumulant analysis method. A dispersion liquid diluted with water so that the concentration of the particles to be measured is about 5 × ^10-3 % by mass is placed in a measurement cell, the temperature is 25 ° C., the number of integrations is 100 times, and the refractive index of the dispersion solvent is water. Enter the refractive index (1.333).

[Concentration of solid content of aqueous dispersion of polyester resin particles]
Using an infrared moisture meter "FD-230" (manufactured by Ketsuto Scientific Research Institute Co., Ltd.), 5 g of the aqueous dispersion was dried at a drying temperature of 150 ° C. and measured in measurement mode 96 (monitoring time 2.5 minutes / fluctuation range 0.05%). It was dried under the conditions, and the water content (mass%) of the aqueous dispersion was measured. The solid content concentration is calculated according to the following formula.
Solid content concentration (mass%) = 100-moisture (mass%)

[PH of aqueous dispersion of polyester resin particles]
Measure at 25 ° C. using a pH meter "HM-20P" (manufactured by DKK-TOA CORPORATION).

[Evaluation method]
[Evaluation of image density]
Inkjet printer "IPSiO GX 2500" (Ricoh Co., Ltd., Piezo method) is filled with water-based ink, and a solid print print pattern (width 204 mm x length 275 mm) is printed by Adobe's Photoshop (registered trademark). Prepare, print on polyester film "Lumirror 75T60" (manufactured by Toray Co., Ltd.) so that the discharge rate is 14 ± 2 g / m ² , place it on a hot plate at 100 ° C for 5 minutes, and then place the printed matter at 25 ° C, relative. After leaving it at a humidity of 50% for 24 hours, the image density of the printed surface is measured. A spectrophotometer "SpectroEye" (manufactured by Gretag Macbeth) is used to measure the image density, and the measurement conditions are the observation light source D65, the observation field of view 2 degrees, and the density reference is DIN16536, and the numerical values of the cyan color density components are read. For the number of measurements, the measurement location is changed, 5 points are randomly selected from the printed portion on the outward route of bidirectional printing, and 5 points are randomly selected from the printed portion on the return route, and the average value of a total of 10 points is calculated. The larger the measured value, the better.

[Evaluation of initial fixability]
Inkjet printer "IPSiO GX2500" (Ricoh Co., Ltd., piezo method) is filled with water-based ink, and a solid print print pattern (width 204 mm x length 275 mm) is created by Adobe's Photoshop (registered trademark). Then, print on the polyester film "Lumirror 75T60" (manufactured by Toray Industries, Inc.) so that the discharge rate is 14 ± 2 g / m ² , place it on a hot plate at 100 ° C for 10 seconds, and then use the cellulose non-woven fabric "Bencot M3-". ^{Apply a load of 500 g (contact area 900 mm 2} ) to "II" (manufactured by Asahi Kasei Co., Ltd.) and rub it 10 times. The damage (scratch) on the surface of the printed matter after rubbing is visually observed to evaluate the fixability. The less scratches on the surface of the printed matter, the better the fixability of the image. Fixability is evaluated according to the following criteria.
A: There are no scratches on the surface of the printed part, and no decrease in gloss is observed.
B: It can be seen that the surface of the printing portion is not scratched, but the gloss is reduced.
C: There is a scratch on the surface of the printing part.
D: The surface of the printing portion is peeled off and the surface of the polyester film is exposed.

[Evaluation of flexibility]
Inkjet printer "IPSiO GX 2500" (Ricoh Co., Ltd., Piezo method) is filled with water-based ink, and a solid print print pattern (width 204 mm x length 275 mm) is printed by Adobe's Photoshop (registered trademark). It was prepared, printed on a polyester film "Lumirror 75T60" (manufactured by Toray Co., Ltd.) so that the discharge rate was 14 ± 2 g / m ² , placed on a hot plate at 100 ° C for 5 minutes, and then the printed matter was placed at 25 ° C. After leaving the printed matter at a relative humidity of 50% for 24 hours, the damage (peeling) of the printed matter after bending the printed matter 50 times at 180 ° C. is visually observed to evaluate the flexibility. The less the peeling of the printed matter, the better the fixing property of the image. Flexibility is evaluated according to the following criteria.
A: No peeling of the printing part and no cracks B: No peeling of the printing part, but cracks occur C: There is peeling of the printing part

[Production example of polyester resin]
Production Examples A1 to A3, A51: Resins A-1 to A-3, A-51
A 10-liter four-necked flask equipped with a thermometer, a stainless stir bar, a flow-down condenser with a dehydration tube, and a nitrogen introduction tube in the amount shown in Table 1 of 2,2-bis (4-hydroxyphenyl) propane (2). .2) Add polyoxypropylene adduct, 2,2-bis (4-hydroxyphenyl) propane (2.0) polyoxyethylene adduct, terephthalic acid, and tin 2-ethylhexanoate (II), and add a nitrogen atmosphere. The temperature was raised to 235 ° C. with stirring, and the temperature was maintained for 5 hours. Then, the pressure inside the flask was further reduced, and the temperature was maintained at 8.3 kPa for 1 hour. Then, after cooling to 200 ° C. and returning to atmospheric pressure, trimellitic anhydride was added, the temperature was raised to 220 ° C., maintained for 1 hour, the pressure in the flask was further lowered, and the softening point was 8.3 kPa. Reacted until the temperature reached the temperature shown in Table 1 to obtain resins A-1 to A-3 and A-51. Table 1 shows the physical characteristics of the obtained resins A-1 to A-3 and A-51.

Production Example A4: Resin A-4
2,2-bis (4-hydroxyphenyl) propane (2.2) shown in Table 1 in a 10-liter four-necked flask equipped with a thermometer, a stainless stir bar, a flow-down condenser with a dehydration tube, and a nitrogen introduction tube. ) Add polyoxypropylene adduct, terephthalic acid and tin 2-ethylhexanoate (II), raise the temperature to 235 ° C with stirring under a nitrogen atmosphere, maintain for 5 hours, and then further reduce the pressure inside the flask. , 8.3 kPa for 1 hour. Then, after cooling to 200 ° C. and returning to atmospheric pressure, fumaric acid, trimellitic anhydride, and 4-tert-butylcatechol were added, and the temperature in the flask was further increased after maintaining the temperature at 210 ° C. for 4 hours. It was lowered and reacted at 8.3 kPa until the softening point reached the temperature shown in Table 1 to obtain resin A-4. Table 1 shows the physical characteristics of the obtained resin A-4.

Production Example A5: Resin A-5
A 10-liter four-necked flask equipped with a thermometer, a stainless stir bar, a flow-down condenser with a dehydration tube, and a nitrogen introduction tube in the amounts shown in Table 1 for 2,2-bis (4-hydroxyphenyl) propane (2). .2) Polyoxypropylene adduct, 2,2-bis (4-hydroxyphenyl) propane (2.0) polyoxyethylene adduct, hydrogenated bisphenol A, terephthalic acid, and tin 2-ethylhexanoate (II) Was added, the temperature was raised to 235 ° C. with stirring under a nitrogen atmosphere, and the temperature was maintained for 8 hours, then the pressure inside the flask was further reduced, and the temperature was maintained at 8.3 kPa for 1 hour. Then, after cooling to 200 ° C. and returning to atmospheric pressure, fumaric acid and 4-tert-butylcatechol were added, maintained at a temperature of 210 ° C. for 4 hours, and then the pressure in the flask was further lowered to 8.3 kPa. The reaction was carried out until the softening point reached the temperature shown in Table 1 to obtain resin A-5. The physical characteristics of the obtained resin A-5 are shown in Table 1.

Production Example A52: Resin A-52
The amount of the raw material monomer was changed to the amount shown in Table 1, and the amount of ethylene glycol shown in Table 1 was further added together with the 2,2-bis (4-hydroxyphenyl) propane (2.2) polyoxypropylene adduct and the like. Resin A-52 was obtained in the same manner as in Production Example A1 except that Table 1 shows the physical characteristics of the obtained resin A-52.

Production Example A53: Resin A-53
The amount of the raw material monomer was changed to the amount shown in Table 1, and together with the 2,2-bis (4-hydroxyphenyl) propane (2.2) polyoxypropylene adduct, etc., the amount shown in Table 1 was changed to the amount shown in Table 1. Resin A-53 was obtained in the same manner as in Production Example A4 except that the (4-hydroxyphenyl) propane (2.0) polyoxyethylene adduct was further added. The physical characteristics of the obtained resin A-53 are shown in Table 1.

[Production example of dispersion liquid of pigment particles]
Production Example P1: Water dispersion of pigment particles P-1
The polyester resin is dissolved in methyl ethyl ketone (referred to as "MEK" in the table) according to the types and formulations shown in Table 2, and 5% by mass sodium hydroxide aqueous solution and ion-exchanged water are added thereto as a neutralizing agent, and the temperature is 10 ° C. or higher. Stirring and mixing was carried out at 2000 rpm for 15 minutes using a disper blade at 15 ° C. or lower. Subsequently, a cyan pigment (CI Pigment Blue 15-3 [indicated as "PB15-3" in the table]) was added, and the mixture was stirred and mixed at 7000 rpm for 3 hours at 10 ° C. or higher and 15 ° C. or lower using a disper blade. The obtained dispersion is filtered by 150 mesh, and after diluting by adding 110 g of ion-exchanged water, a high-pressure homogenizer "Microfluidizer, model M-110K" (manufactured by Microfluidics) is used for 15 passes at a pressure of 150 MPa. Distributed processing was performed.
Methyl ethyl ketone is removed from the obtained dispersion at 60 ° C. under reduced pressure, some water is further removed, the mixture is centrifuged, and the liquid layer portion is filtered through a filter (manufactured by Pall) having a pore size of 10 μm to obtain coarse particles. Excluded. Ion-exchanged water was mixed so as to have a solid content concentration of 20%, and then filtered through the filter having a pore size of 10 μm to obtain an aqueous dispersion liquid P-1 of pigment particles. Table 2 shows the physical characteristics of the obtained aqueous dispersion.

[Production example of aqueous dispersion of polyester resin particles]
Production Examples E1 to E5, E51 to E53: Aqueous dispersion of polyester resin particles E-1 to E-5, E-51 to E-53
Put the polyester resin of the type and amount shown in Table 3 into a 1L four-necked flask equipped with a nitrogen introduction pipe, a reflux condenser, a stirrer "Three One Motor BL300" (manufactured by Shinto Kagaku Co., Ltd.) and a thermocouple. It was mixed with 200 g of methyl ethyl ketone at 30 ° C. and dissolved. Then, the amount of 5 mass% sodium hydroxide aqueous solution shown in Table 3 was added, and the mixture was stirred for 30 minutes, and then the entire amount of deionized water was added dropwise at a rate of 20 mL / min under stirring at 30 ° C. Then, after raising the temperature to 60 ° C., methyl ethyl ketone was distilled off while gradually reducing the pressure to 80 kPa to 30 kPa. After cooling to 25 ° C., the mixture was filtered through a 150 mesh wire mesh and adjusted to a solid content of 30% by mass with ion-exchanged water to obtain an aqueous dispersion containing polyester resin particles. Table 3 shows the physical characteristics of the obtained aqueous dispersions E-1 to E-5 and E-51 to E-53.

[Manufacturing of water-based ink]
Examples 1 to 4,7, Comparative Examples 1 to 3 (Manufacturing of water-based inks 1 to 4, 7, 51 to 53)
Propylene glycol (manufactured by Wako Pure Chemical Industries, Ltd.) 20.0 parts by mass, 1,2-butanediol (manufactured by Wako Pure Chemical Industries, Ltd.) 10.0 parts by mass, acetylene glycol-based surfactant "Orfin" in a 100 mL screw tube 1.0 part by mass of "E1010" (manufactured by Nissin Chemical Industry Co., Ltd.) and 21.3 parts by mass of ion-exchanged water were mixed and stirred with a magnetic stirrer at room temperature for 15 minutes to obtain a mixed solution.
While stirring 28.6 parts by mass of the aqueous dispersion containing the produced pigment (4.0 parts by mass in terms of pigment content (in 100 parts by mass of water-based ink)) with a magnetic stirrer, the mixed solution is further mixed. 19.1 parts by mass of an aqueous dispersion containing polyester resin particles (5.7 parts by mass in terms of solid content (in 100 parts by mass of water-based ink)) was added dropwise with a dropper and mixed by stirring. Finally, it was filtered with a filter "Mini Sartorius" (manufactured by Sartorius Stedim Biotech) having a pore size of 5.0 μm to obtain an aqueous ink. Table 4 shows the evaluation results of the obtained water-based ink.

Example 5 (Manufacturing of water-based ink 5)
Propylene glycol (manufactured by Wako Pure Chemical Industries, Ltd.) 20.0 parts by mass, 1,2-butanediol (manufactured by Wako Pure Chemical Industries, Ltd.) 10.0 parts by mass, acetylene glycol-based surfactant "Orfin" in a 100 mL screw tube 1.0 part by mass of "E1010" (manufactured by Nissin Chemical Industry Co., Ltd.) and 5.1 parts by mass of ion-exchanged water were mixed and stirred with a magnetic stirrer at room temperature for 15 minutes to obtain a mixed solution.
While stirring 28.6 parts by mass of the aqueous dispersion containing the produced pigment (4.0 parts by mass in terms of pigment content (in 100 parts by mass of water-based ink)) with a magnetic stirrer, the mixed solution is further mixed. 35.3 parts by mass of the aqueous dispersion containing the polyester resin (10.6 parts by mass in terms of solid content (in 100 parts by mass of the water-based ink)) was added dropwise with a dropper and mixed by stirring. Finally, it was filtered with a filter "Mini Sartorius" (manufactured by Sartorius Stedim Biotech) having a pore size of 5.0 μm to obtain an aqueous ink. Table 4 shows the evaluation results of the obtained water-based ink.

Example 6 (Manufacturing of water-based ink 6)
Propylene glycol (manufactured by Wako Pure Chemical Industries, Ltd.) 20.0 parts by mass, 1,2-butanediol (manufactured by Wako Pure Chemical Industries, Ltd.) 10.0 parts by mass, acetylene glycol-based surfactant "Orphine E1010" in a 100 mL screw tube (Manufactured by Nissin Chemical Industry Co., Ltd.) 1.0 part by mass and 30.2 part by mass of ion-exchanged water were mixed and stirred with a magnetic stirrer at room temperature for 15 minutes to obtain a mixed solution.
While stirring 28.6 parts by mass of the aqueous dispersion containing the produced pigment (4.0 parts by mass in terms of pigment content (in 100 parts by mass of water-based ink)) with a magnetic stirrer, the mixed solution is further mixed. 10.2 parts by mass of an aqueous dispersion containing a polyester resin (3.1 parts by mass in terms of solid content (in 100 parts by mass of water-based ink)) was added dropwise with a dropper and mixed by stirring. Finally, it was filtered with a filter "Mini Sartorius" (manufactured by Sartorius Stedim Biotech) having a pore size of 5.0 μm to obtain an aqueous ink. Table 4 shows the evaluation results of the obtained water-based ink.

From the above-mentioned Examples and Comparative Examples, it can be seen that when the colorant particles and the polyester resin particles contain the predetermined polyester resin A, a water-based ink having excellent image density, image fixability, and flexibility can be obtained.

Claims (6)

A water-based ink containing colorant particles and polyester resin particles.
A polycondensate of an alcohol component containing 70 mol% or more of an alkylene oxide adduct of bisphenol A and a carboxylic acid component containing 50 mol% or more of an aromatic dicarboxylic acid, in which the colorant particles and the polyester resin particles are the same or different, respectively. includes a polyester resin a is and Ri 160 ° C. der than the softening point of 125 ° C. or more of the polyester resin a, a polyester resin a in at least one of colorant particles and the polyester resin particles, have a crosslinked structure and, the colorant particles and the carboxylic acid component of the polyester resin a in at least one of the polyester resin particles, you containing trivalent or higher polyvalent carboxylic acid more than 25 mol% to 10 mol%, the water-based ink. The water-based ink according to claim 1 , wherein the polyester resin A has a glass transition temperature of 60 ° C. or higher and 85 ° C. or lower. The content of the alkylene oxide adduct of bisphenol A in the alcohol component of the polyester resin A contained in the colorant particles Al _c (mol%) and the bisphenol A in the alcohol component of the polyester resin A contained in the polyester resin particles. The water-based ink according to claim 1 or 2 , wherein the content of the alkylene oxide adduct of the above _{(Al r} (mol%)) satisfies the following relational expression (1).
｜ Al _{c −} Al _r ｜ ≦ 30 (1) The content of aromatic dicarboxylic acid in the carboxylic acid component of the polyester resin A contained in the colorant particles Ca _c (mol%) and the aromatic dicarboxylic acid in the carboxylic acid component of the polyester resin A contained in the polyester resin particles. a content of the acid Ca r _(mol%), but satisfy the following relationship (2), the water-based ink according to any one of claims 1-3.
_{| Ca c -Ca r | ≦ 30} (2) The softening point Tm c _(° C.) of the polyester resin A contained in the colorant particles, the softening point Tm r _(° C.) of the polyester resin A contained in the polyester resin particles, but satisfies the following relationship (3) , The water-based ink according to any one of claims 1 to 4.
｜ Tm _{c − Tm r} ｜ ≦ 30 (3) The polyester resin A in the polyester resin particles has a crosslinked structure, and the carboxylic acid component of the polyester resin A in the polyester resin particles contains 10 mol% or more and 25 mol% or less of a trivalent or higher polyvalent carboxylic acid. The water-based ink according to any one of claims 1 to 5.