JP4905393B2 - Ink-receptive particles, method for producing the same, and curable resin dispersion - Google Patents

Description

  The present invention relates to ink receiving particles, a method for producing the same, and a curable resin dispersion.

  One of recording methods for images and data using ink is an inkjet recording method. The principle of the ink jet recording system is to record on paper, cloth, film, etc. by discharging liquid or molten solid ink from a nozzle, slit, porous film or the like. As for the method for ejecting ink, the so-called charge control method in which ink is ejected using electrostatic attraction, the so-called drop-on-demand method (pressure pulse method) in which ink is ejected using the vibration pressure of a piezo element. Various methods have been proposed, such as a so-called thermal ink jet method, in which ink is ejected using pressure generated by the formation and growth of bubbles due to high heat. By these methods, extremely high-definition images and data are Records can be obtained.

  In order to perform high-quality recording on various recording media such as penetrating media and non-penetrating media, recording methods using ink, including this ink jet recording method, are recorded on an intermediate transfer member and then transferred to the recording medium. A method has been proposed.

  For example, a method has been proposed in which recording is performed while supplying a plurality of types of powder mixtures onto an intermediate, such as polymers having different water absorption, water absorption polymers having different sizes, and water absorption polymers having different degrees of crosslinking. 1).

In addition, a method for recording while supplying solid particles (particles of polysaccharide polymer, alginic acid, carrageenan, etc.) that thicken the ink by contact with the ink on the intermediate is proposed (for example, see Patent Document 2). ).
Further, a method in which a hydrophobic resin particle layer is formed on an intermediate, and ink (for example, SD type dye ink slow dry type (slow dry type)) is held in the voids of the hydrophobic resin particle layer and transferred to a recording medium. Has been proposed (see, for example, Patent Document 3).

  As the water-absorbent resin particles used in the resin particle layer, particles having a non-swellable core and a swellable shell in water are disclosed (for example, see Patent Documents 4 and 5). Specifically, a copolymer having a carboxyl group-containing monomer or acrylamide monomer of less than 10% by mass is used for the core part, and a copolymer of 10% by mass to 60% by mass is used for the shell part.

Further, acrylic polymer particles having a hydroxyl group, acrylamide polymer particles, and quaternary ammonium salt-containing acrylamide polymer particles are disclosed as hydrophilic resins (see, for example, Patent Documents 6 to 8).
Furthermore, an ink receiving layer composition comprising an ultraviolet curable resin, a hydrophilic polymer and a filler is disclosed (for example, see Patent Document 9). This is characterized in that the hydrophilic polymer becomes particulate after UV curing, and the amount of filler can be reduced.
JP 2000-343808 A JP 2000-94654 A JP 2003-57967 A JP 2006-335004 A JP 2006-110986 A JP 2006-327166 A JP 2006-346879 A JP 2006-256020 A JP-A-8-176428

  The present invention relates to ink-receptive particles capable of high-speed, high-quality, and high-durability recording on various recording media (mainly non-penetrable media) that are difficult to record with conventional water-based and oil-based ink jet recording, and production thereof It is an object to provide a method and a curable resin dispersion using the method.

The above-described problems are achieved by the present invention described below.
That is, the invention according to claim 1 includes polymer particles, and the polymer particles are 4.5 parts by mass to 30 parts by mass of styrene, 18.5 parts by mass to 40 parts by mass of butyl methacrylate, and monophthalate. 2 contains a (methacryloyloxy) ethyl 25.0 parts by ～72.0 parts by weight, divinylbenzene 1.1 parts by to 2.2 parts by weight, the resin is a copolymer, and the polymerization The ink receiving particles are characterized in that the acid groups of the combined particles are neutralized with a base, and the volume average particle size of the polymer particles is 0.3 μm or more and 0.4 μm or less.

The invention according to claim 2 is an ink receiving particles of claim 1 composed of at least one of agglutination and fusion of the polymer particles.

  In the invention according to claim 3, the acidic group amount of the polymer particles is 1.0 mmol / g or more and 3.5 mmol / g or less, and the volume average particle size of the particles composed of the polymer particles is 1.0 μm. 3. The ink receiving particle according to claim 1, wherein the particle size is 20 μm or less.

  The invention according to claim 4 is the ink receptive particle according to any one of claims 1 to 3, having a water absorption rate of 200% or more and 5000% or less.

The invention according to claim 5 is a curable resin dispersion comprising the ink receiving particles according to any one of claims 1 to 4 and a curable resin.

The invention according to claim 6, wherein a volume average particle diameter of the ink receiving particles are curable resin dispersion according to claim 5 is 1μm or more 5μm or less.

The invention according to claim 7 includes 4.5 parts by mass to 30 parts by mass of styrene, 18.5 parts by mass to 40 parts by mass of butyl methacrylate, and 25.0 parts by mass of mono-2- (methacryloyloxy) ethyl phthalate. Polymer particle preparation step of preparing polymer particles of ~ 72.0 parts by mass and 1.1 parts by mass to 2.2 parts by mass of divinylbenzene ;
A neutralization step of neutralizing the acidic groups of the polymer particles with a base;
And an aggregate particle forming step using the polymer particles as aggregate particles.

The invention according to claim 8 is characterized in that the aggregate particle forming step includes
An aggregation / fusion process for aggregating / fusion of the polymer particles;
Wherein a manufacturing method of the ink receiving particles of claim 7 having a pulverizing step of pulverizing the aggregate-Fused polymeric particles.

According to the first aspect of the present invention, high-speed recording with high image quality and high durability can be performed on various recording media (mainly non-penetrable media) that are difficult to record with conventional water-based and oil-based inkjet recording. Possible ink receptive particles are provided.
According to the second aspect of the invention, it is possible to obtain ink-receptive particles that are superior in high speed and high image quality due to both high liquid absorption and a large colorant holding area.
According to the third aspect of the present invention, ink receptive particles that are superior in balance between the liquid absorption and the image quality can be obtained.
According to the fourth aspect of the present invention, ink-receptive particles that are superior in balance between liquid absorption and image quality can be obtained.
According to the first aspect of the present invention, it is easy to adjust the hydrophilicity and hydrophobicity, and it is possible to obtain ink receiving particles that are excellent in the balance between the liquid absorption and the image quality.
According to the invention of claim 5 , the peelability and fixability of the ink receiving particles capable of high-speed, high-quality, and high-durability recording on various recording media (mainly non-penetrating media) are improved. Can be made.
According to the invention which concerns on Claim 6 , the curable resin dispersion in which a higher quality image formation is possible is obtained.
According to the seventh aspect of the present invention, ink receptive particles capable of high-speed, high-quality and high-durability recording can be efficiently obtained for various recording media (mainly non-penetrating media).
According to the eighth aspect of the invention, ink receptive particles capable of high-speed, high-quality and high-durability recording on various recording media (mainly non-penetrating media) can be obtained more easily.

Hereinafter, embodiments of the present invention will be described in detail.
<Ink Receptive Particles and Manufacturing Method Thereof>
The ink receiving particles of the present embodiment include polymer particles, and the polymer particles contain a resin having a structural unit represented by the following structural formula (I).
However, in the ink receiving particles of this embodiment, as polymer particles, 4.5 parts by mass to 30 parts by mass of styrene, 18.5 parts by mass to 40 parts by mass of butyl methacrylate, and mono-2- (phthalate) a methacryloyloxy) ethyl 25.0 parts by ～72.0 parts by mass contains divinylbenzene 1.1 parts by to 2.2 parts by weight, the resin is a copolymer, the acid groups of the polymer particles Polymer particles neutralized with a base and having a volume average particle diameter of 0.3 μm or more and 0.4 μm or less are applied.

In the structural formula (I), R represents hydrogen or a methyl group, n represents an integer of 1 to 18, and X ⁺ represents any one of an alkali metal ion, an alkaline earth metal ion, and a quaternary ammonium ion.

The ink receiving particles are for receiving ink. Here, “ink receptivity” means holding at least a part of ink components (at least a liquid component).
In the ink receiving particles of the present embodiment, since the resin component constituting the polymer particles includes the structural unit having the salt structure, when ink is first attached to the ink receiving particles, at least the ink liquid is received. The component penetrates into the gap between the polymer particles constituting the ink receiving particles. At this time, although the reason is not clear, the coloring component of the ink components is adsorbed on the surface of the ink receiving particles regardless of pigments or dyes and stays efficiently. In this manner, the ink receiving particles of the present embodiment receive ink without diffusing the coloring component.

Further, in the ink receiving particles of the present embodiment, the water absorption rate of the ink receiving particles is set within a certain range by controlling the type and composition of the copolymerization component of the resin contained in the polymer particles as described later. Therefore, excessive swelling of the ink receiving particles can be suppressed, and further, ink bleeding and the like can be avoided.
Then, high-quality recording is performed by transferring the ink receiving particles of the present embodiment that have received ink to a recording medium.

  Penetration of the ink liquid component into the gap between the polymer particles is a trapping of the liquid by a physical particle wall structure. However, since the particle wall is hydrophilic, the liquid absorption speed is fast and the drying time is shortened. For this reason, the ink receptive particles that have received the ink can be transferred to various recording media in a short time regardless of the permeation medium or the non-penetration medium.

Hereinafter, the configuration of the ink receiving particles of the present embodiment will be described together with the manufacturing method thereof.
(Polymer particles)
The polymer particles used in the ink receiving particles of this embodiment contain a resin having a structural unit represented by the structural formula (I). Since the carboxylate in the structural unit has high hydrophilicity, the liquid component (for example, water, aqueous solvent) in the ink in contact with the ink receiving particles including the polymer particles is efficiently particles. It penetrates into the inside, and the retention ability of the liquid component of the particles is improved. Therefore, for example, even if various inks are used, recording on various recording media can be performed at high speed.

On the other hand, if the permeability of the liquid component is too high, the ink-receptive particles will swell too much, and, for example, when transferred to a recording medium as ink-receptive particles, the particles will spread greatly and the image will be distorted. May end up.
In the ink receiving particles of the present embodiment, as described later, the resin contained in the polymer particles is copolymerized with the structural unit represented by the structural formula (I) with another hydrophobic monomer, or a crosslinking component. The water absorption as the whole particle | grains is easily controlled by comprising by introduce | transducing.

Specifically, in the present embodiment, the water absorption rate of the ink receiving particles is preferably 200% or more and 5000% or less, and more preferably 400% or more and 3000% or less.
If the water absorption rate is less than 200%, the liquid once trapped in the voids of the particles may easily overflow from the voids or deteriorate the image when the particles are transferred to the recording medium. On the other hand, if it exceeds 5000%, not only the liquid absorption but also the moisture absorption is active, so that the environmental dependency of the handling of the ink receiving particles becomes large and it may be difficult to use. Furthermore, the storage stability of the image in a high humidity environment may be deteriorated.
In addition, the water absorption rate in this embodiment is measured according to JIS K7209 (1984). Details will be described later.

The resin contained in the polymer particles in the present embodiment is, for example, a homopolymer of a hydrophilic monomer serving as the structural unit represented by the structural formula (I), or the hydrophilic monomer and a hydrophobic monomer. It is preferable that the resin is composed of a copolymer composed of both monomers with the body, but from the above viewpoint, the resin in the present embodiment is so-called saturated with a certain amount of water absorption (liquid absorption). A weak water-absorbing resin is desirable, and the copolymer is preferable in order to obtain a weak water-absorbing resin.
Here, the “hydrophilic monomer” includes a monomer that is itself hydrophobic but can be easily hydrophilized after polymerization.

As the hydrophilic monomer component constituting the resin, in addition to the monomer composed of the unit represented by the structural formula (I), a monomer having another structure may be included. As the monomer having the other structure, a monomer having an acidic group is desirable. Specifically, a monomer having a carboxyl group is used, and after the polymerization, the carboxylic acid is neutralized with a base such as NaOH, Forming a salt (neutralized salt) structure is desirable in terms of obtaining good water absorption, and it is particularly desirable to use an ethylenically unsaturated monomer having a carboxyl group.
Examples of the monomer having a carboxyl group used in this embodiment include acrylic acid, methacrylic acid, methacryloyloxyethyl monohexahydrophthalate, methacryloyloxyethyl monomaleate, methacryloyloxyethyl monosuccinate, and acryloyloxyethyl monophthalate. And acryloyloxyethyl monohexahydrophthalate and acryloyloxyethyl monosuccinate.

  Examples of the hydrophobic monomer include monomers having a hydrophobic group. Specifically, for example, olefin (ethylene, butadiene, etc.), styrene, α-methylstyrene, α-ethylstyrene, methyl methacrylate. , Ethyl methacrylate, butyl methacrylate, acrylonitrile, vinyl acetate, methyl acrylate, ethyl acrylate, butyl acrylate, lauryl methacrylate, and the like. Hydrophobic units or monomers include styrene derivatives such as styrene, α-methylstyrene, vinyltoluene, vinylcyclohexane, vinylnaphthalene, vinylnaphthalene derivatives, alkyl acrylate esters, phenyl acrylate esters, alkyl methacrylate esters, methacrylic acid Examples also include phenyl esters, cycloalkyl methacrylates, alkyl esters of crotonic acid, dialkyl esters of itaconic acid, dialkyl maleates, polyolefins such as polyethylene, ethylene / vinyl acetate and polypropylene, and derivatives thereof.

  In the resin contained in the polymer particles in the present embodiment, the molar ratio (hydrophilicity) between the hydrophilic unit (part composed of a hydrophilic monomer) and the hydrophobic unit (part composed of a hydrophobic monomer). The monomer is preferably in the range of 5:95 to 90:10, more preferably in the range of 7:93 to 80:20, and still more preferably in the range of 10:90 to 70:30. It is. By setting the amount of the hydrophilic monomer in the above range, the liquid absorption speed and the amount of liquid absorption when the ink receiving particles absorb the aqueous medium or the like in the ink can be controlled within an appropriate range. In addition, for example, when the ink receiving particles are uniformly arranged on the intermediate transfer member, a certain degree of chargeability of the particles is required, but a certain degree of chargeability can be imparted by imparting hydrophobicity to the particles. .

  The resin having the structural unit represented by the structural formula (I) is a copolymer including the structural units (A), (B), and (C) represented by the following structural formula (II). In terms of controlling the balance between hydrophilicity and hydrophobicity, it is desirable in terms of ease of control, ease of particle size control, and the like.

In the structural formula (II), R, n, and X ⁺ are the same as those described in the structural formula (I). R ¹ represents any one of alkyl groups having 1 to 18 carbon atoms. The structural unit (A) represented by the structural formula (II) corresponds to that based on the hydrophilic monomer, and the structural units (B) and (C) correspond to those based on the hydrophobic monomer. To do.

Further, when the above three structural units are included, the molar ratio of each structural unit (A), (B) and (C) is 10 mol% or more and 90 mol% or less, 0 mol% or more and 90 mol% or less, 0 It is desirable to set it in the range of mol% to 90 mol%.
More specifically, the molar ratio P of the structural unit (A) in the copolymer is 10 mol% to 90 mol%, and the remaining molar ratio (100-P) of the structural units (B) and (C) The sum is desirable. At this time, the ratio of the structural units (B) and (C) is preferably in the range of 0/90 to 90/0.

In addition, the resin contained in the polymerizable particles in the present embodiment may have a linear structure or a branched structure. That is, the resin may be a linear random copolymer or block copolymer, but branched polymers (including branched random copolymers, block copolymers, and graft copolymers) are also suitable. Can be used for
Further, the resin may contain a crosslinked structure. By including a crosslinked structure in the resin, the liquid absorption amount may be constant and excessive swelling may be suppressed. Such a cross-linked structure can be synthesized by adding a small amount of a so-called cross-linking agent such as divinylbenzene or di (meth) acrylate during synthesis, or by adding a large amount of an initiator together with the cross-linking agent.

As the crosslinking agent to be used, a known crosslinking agent can be selected and used. Examples of suitable crosslinking agents include divinylbenzene, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, methylene bis (meth) acrylamide, Examples thereof include glycidyl (meth) acrylate and 2-([1′-methylpropylideneamino] carboxyamino) ethyl methacrylate. Among these, divinylbenzene, ethylene glycol di (meth) acrylate, and diethylene glycol di (meth) acrylate are more preferable, and divinylbenzene is particularly preferable.
The addition amount of the cross-linking agent is preferably 0 to 5 parts by mass, more preferably 0 to 3 parts by mass with respect to 100 parts by mass of all monomer components. is there.

The resin is desirably an amorphous resin, and the glass transition temperature (Tg) thereof is preferably 0 ° C. or higher and 100 ° C. or lower, more preferably 20 ° C. or higher and 80 ° C. or lower. By setting the glass transition temperature in the above range, the storability of the image after fixing can be improved, and further, the fused particles in the production of the ink receiving particles described later can be easily pulverized.
In addition, the glass transition temperature was calculated | required from the main body maximum peak measured based on ASTMD3418-8. DSC-7 manufactured by Perkin Elmer Co. can be used for measurement of the main maximum peak. The temperature correction of the detection part of this apparatus uses the melting point of indium and zinc, and the correction of heat quantity uses the heat of fusion of indium. As the sample, an aluminum pan was used, an empty pan was set as a control, and the measurement was performed at a heating rate of 10 ° C./min.

  The weight average molecular weight of the resin is preferably 1000 or more and 1000000 or less, more preferably 5000 or more and 500000 or less. By setting the weight average molecular weight within the above range, it is possible to achieve both quick liquid absorption, good fixing, and image strength after fixing. The weight average molecular weight was measured under the following conditions. For example, GPC uses “HLC-8120GPC, SC-8020 (manufactured by Tosoh Corporation)” apparatus, and two columns are “TSKgel, SuperHM-H (6.0 mm ID × 15 cm, manufactured by Tosoh Corporation)”. And THF (tetrahydrofuran) was used as the eluent. As experimental conditions, the sample concentration was 0.5%, and the flow rate was 0.6 ml / min. The experiment was conducted using a sample injection amount of 10 μl, a measurement temperature of 40 ° C., and an IR detector. The calibration curve is “polystylen standard sample TSK standard” manufactured by Tosoh Corporation: “A-500”, “F-1”, “F-10”, “F-80”, “F-380”, “A-2500”. ”,“ F-4 ”,“ F-40 ”,“ F-128 ”, and“ F-700 ”.

  Furthermore, the acid value of the resin is 50 mgKOH / g or more and 1000 mgKOH / g or less in terms of carboxylic acid group (—COOH), more preferably 150 mgKOH / g or more and 500 mgKOH / g or less, more preferably 100 mgKOH / g or more. 300 mgKOH / g or less. By controlling the acid value within the above range, it becomes possible to control the handling properties, water absorption and fixing properties of the particles. The acid value in terms of this carboxylic acid group (—COOH) was measured as follows.

  The acid value was measured according to JIS K0070 and using a neutralization titration method. That is, an appropriate amount of a sample is taken, 100 ml of a solvent (diethyl ether / ethanol mixed solution) and a few drops of an indicator (phenolphthalein solution) are added, and shaken sufficiently until the sample is completely dissolved in a water bath. This was titrated with a 0.1 mol / l potassium hydroxide ethanol solution, and the end point was when the indicator was light red for 30 seconds. When the acid value is A, the sample amount is S (g), the 0.1 mol / l potassium hydroxide ethanol solution used for the titration is B (ml), and f is the factor of the 0.1 mol / l potassium hydroxide ethanol solution. , A = (B × f × 56.11) / S.

The polymer particles in the present embodiment can further contain other resin components.
Examples of the resin component include thermoplastic binder resins, and specifically, homopolymers or copolymers (styrene-based resins) of styrenes such as styrene, parachlorostyrene, and α-methylstyrene; Methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, n-butyl (meth) acrylate, lauryl (meth) acrylate, 2-ethylhexyl (meth) acrylate, (meta ) Homopolymers or copolymers of vinyl groups such as lauryl acrylate (vinyl resins); Homopolymers or copolymers of vinyl nitriles such as acrylonitrile and methacrylonitrile (vinyl resins) Homopolymers or copolymers of vinyl ethers such as vinyl methyl ether and vinyl isobutyl ether (vinyl resins); Homopolymers or copolymers of vinyl ketones such as rumethyl ketone, vinyl ethyl ketone, and vinyl isopropenyl ketone (vinyl resins); Homopolymers or copolymers of olefins such as ethylene, propylene, butadiene, and isoprene (olefins) Resin); non-vinyl condensation resins such as epoxy resins, polyester resins, polyurethane resins, polyamide resins, cellulose resins, polyether resins, and graft polymers of these non-vinyl condensation resins and vinyl monomers. Can be mentioned. These resins may be used alone or in combination of two or more. Among these resins, styrene resins, vinyl resins, polyester resins, and olefin resins are preferable, copolymers of styrene and n-butyl (meth) acrylate, n-butyl (meth) acrylate, bisphenol A. -A fumaric acid copolymer and a copolymer of styrene and olefin are particularly preferred.

(Manufacture of ink receiving particles)
Next, a method for producing the ink receiving particles of this embodiment will be described.
As a result of studying the production method for obtaining the above-described ink-receiving particles by the present inventors, the reason is not clear. However, the monomer and the hydrophobic monomer as the structural unit represented by the structural formula (I) It was found that in the case of mixing with a body and subjecting it to suspension polymerization in water, the particles tend to aggregate during the polymerization and it is difficult to form uniform ink receiving particles.

For this reason, the ink receiving particles of the present embodiment are formed in advance in the form of polymer particles containing a resin having a structural unit represented by the following structural formula (III) by emulsion polymerization and the like, and are mixed and granulated in an aqueous medium. After (aggregation), neutralization reaction is performed to obtain ink-receptive particles, or polymer particles containing a resin having a structural unit represented by the following structural formula (III) are formed in advance by emulsion polymerization or the like. After the neutralization reaction, the polymer particles are desirably aggregated and fused (aggregated), and then the resulting fused body is pulverized for production. By this method, ink receiving particles containing a liquid-absorbing resin can be obtained by a simple process.
When the agglomeration is performed, in the obtained aggregate, the polymer particles may be in a coalesced state, in an agglomerated state, or in a state where agglomeration / fusion is mixed. May be.

  In the structural formula (III), R represents hydrogen or a methyl group, and n represents an integer of 1 to 18, respectively.

  The polymer particles can be easily obtained by an emulsion polymerization method or a heterogeneous dispersion polymerization method similar thereto. In addition, a polymer that has been uniformly polymerized by a solution polymerization method, a bulk polymerization method, or the like in advance can be obtained by an arbitrary method such as a method in which a polymer is added to a solvent in which the polymer is not dissolved together with a stabilizer and mechanically mixed and dispersed Can do.

  For example, when the monomer used is a vinyl monomer (ethylenically unsaturated monomer), polymer particles are obtained by carrying out emulsion polymerization using an ionic surfactant or the like according to the production method. A dispersion can be made. Further, even when polymerized by other methods, if the resin is oily and dissolves in a solvent having a relatively low solubility in water, the resin is dissolved in those solvents and an ionic surfactant or A dispersion of polymer particles can be prepared by dispersing fine particles in water with a polymer electrolyte and a disperser such as a homogenizer, and then evaporating the solvent by heating or decompressing.

  Examples of the surfactant include anionic surfactants such as sulfate ester sulfonates, phosphate esters and soaps; cationic surfactants such as amine salts and quaternary ammonium salts; polyethylene glycols Nonionic surfactants such as alkylphenol ethylene oxide adduct system, alkyl alcohol ethylene oxide adduct system, polyhydric alcohol system, and various graft polymers can be exemplified, but are not particularly limited.

  When preparing a polymer particle dispersion by emulsion polymerization, a protective colloid layer can be formed with a small amount of unsaturated acid such as acrylic acid, methacrylic acid, maleic acid, styrene sulfonic acid, etc. This is particularly preferable because it enables polymerization.

As the polymerization initiator used in the present embodiment, azo polymerization initiators, peroxide initiators and the like can be mentioned as preferable ones, and among them, a water-soluble initiator is desirable.
Water-soluble azo initiators include 2,2′-azobis [N- (2-hydroxyethyl) -2-methyl-propionamidine] dihydrochloride, 2,2′-azobis (2-amidinopropane) dihydrochloride 2,2′-azobis [2- (2-imidazolin-2-yl) propane] dihydrochloride, 2,2′-azobis [2- (2-imidazolin-2-yl) propane], 4,4 ′ -Azobis (4-cyanovaleric acid) etc. are mentioned.
Examples of the water-soluble peroxide initiator include ammonium persulfate, potassium persulfate, and hydrogen peroxide.

  The addition amount of the polymerization initiator is not particularly limited, but is preferably in the range of 0.05 to 10 parts by mass with respect to 100 parts by mass of all monomer components, and is 0.1 to 5 parts by mass. It is more preferable that the amount is not more than part.

The polymerization reaction can be carried out not only in the air but also under pressure, but these other reaction conditions are applied as necessary and are not particularly limited.
As the reaction conditions, for example, a reaction at a reaction temperature of 40 ° C. to 100 ° C. for 1 to 24 hours while stirring the emulsion in which the emulsified particles are dispersed is performed at atmospheric pressure, and a high yield of about 80% or more is obtained. From the standpoint of obtaining polymer particles at a high rate.

The particle diameter of the polymer particles in the polymer particle dispersion is required to be 0.1 μm or more and 1 μm or less in terms of volume average particle diameter, and more preferably in the range of 100 nm or more and 800 nm or less. When the volume average particle diameter exceeds 1 μm, the dispersion stability is deteriorated.
The volume average particle size of the polymer particles was measured with a laser diffraction type particle size distribution measuring device (LA-700, manufactured by Horiba, Ltd.).

In addition, the acidic group amount of the polymer particles in the present embodiment is desirably in the range of 1.0 mmol / g to 3.5 mmol / g, and in the range of 1.5 mmol / g to 3.0 mmol / g. More desirable.
If the amount of acidic groups is less than 1.0 mmol / g, sufficient liquid absorbency may not be obtained when they are brought into contact with ink even if they have a salt structure. If it exceeds 3.5 mmol / g, the liquid absorbency becomes too large, and it may be difficult to handle as ink-receptive particles or the image quality may be lowered.

  The amount of the acidic group can be determined by a general titration method as will be described later. For example, a certain amount of a reagent such as an ethanol solution of potassium hydroxide is added to the polymer particles to carry out a neutralization reaction, and the particles and supernatant are separated by a centrifuge, and the supernatant containing excess potassium hydroxide is automatically removed. The amount of carboxyl groups can be determined by titrating with an isopropanol hydrochloric acid solution or the like using a titration apparatus.

For example, when a salt structure (-COO ^- Y ⁺ : where Y ⁺ represents an organic cation such as an alkali metal ion, an alkaline earth metal ion, or ammonium) is formed by neutralization of a carboxyl group, for example. After the salt is converted to carboxylic acid with an acid such as hydrochloric acid, the amount of carboxyl groups can be determined by performing the above-described titration.
That is, the carboxyl group amount (acidic group amount) in the present embodiment means the carboxyl group amount including the carboxyl group contributing to the salt structure when the carboxyl group forms a salt structure.

  As described above, the ink-receptive particles of the present embodiment are formed by (Method 1) polymer particles including a resin having a structural unit represented by the structural formula (I) by emulsion polymerization or the like in advance in an aqueous medium. After granulation (aggregate particles), neutralization reaction is performed to obtain ink-receptive particles, or (Method 2) a resin having the structural unit represented by the structural formula (I) is previously obtained by emulsion polymerization or the like. It is desirable to form polymer particles containing the particles, agglomerate and fuse them, and then pulverize the resulting fusion product (aggregate particles).

In the case of (Method 1), polymer particles containing a resin having the structural unit represented by the structural formula (I), and if necessary, other resins and other additives are dissolved and dispersed in an organic solvent such as ethyl acetate. This oily mixture is emulsified in an aqueous medium containing a dispersant stabilizer using an emulsifier or a disperser to form an oil-in-water aqueous suspension, and then desolvated by an in-liquid drying method. Aggregated particles are obtained. Next, the aggregated particles obtained by the in-liquid drying method are neutralized with a basic compound in the presence of water or a mixed liquid of water and a water-soluble organic solvent to obtain the ink receiving particles of this embodiment. be able to. In addition, since the said aggregate particle in this embodiment is not what the polymer particles fuse | melted firmly, the acidic group of a polymer particle can be neutralized by the said neutralization process.
In the present embodiment, the treatment may be performed by adding a basic compound to the aqueous dispersion of aggregate particles, or the aggregate particles may be mixed and treated in an aqueous solution in which the basic compound is dissolved. . The neutralization treatment can be performed in the same manner as described later (Method 2).

In the case of (Method 2), since a part or all of the carboxyl groups in the resin having the structural unit represented by the structural formula (I) contained in the polymer particles prepared by emulsion polymerization or the like in advance have a salt structure, fusion It is desirable to neutralize with a basic compound or the like if necessary. This is because the carboxyl group in the resin has a salt structure, the liquid absorbency of the resin is increased and the resin easily swells, and aggregation and fusion described later are promoted.
In the same manner as described above, for example, the polymer particles may be treated with a basic compound in the presence of water or a mixed liquid of water and a water-soluble organic solvent. In the present embodiment, the treatment may be performed by adding a basic compound to the aqueous dispersion of polymer particles, or the polymer particles may be mixed and treated in an aqueous solution in which the basic compound is dissolved. .

As the basic compound, either an inorganic basic compound or an organic basic compound can be used. Specifically, inorganic basic compounds such as sodium hydroxide, potassium hydroxide and ammonia; organic basic compounds such as tetramethylammonium hydroxide and tetraethylammonium hydroxide; other basic trimethylamines, diethylamine, triethylamine, trimethylamine Alkylamines such as propylamine and tributylamine; alkanolamines such as monoethanolamine, methylethanolamine, diethanolamine, diisopropanolamine, triethanolamine, dimethylaminoethanol and morpholine;
These basic compounds may be used alone or in combination of two or more. Moreover, it is desirable to use an inorganic basic compound from the viewpoint of easy removal of the basic compound after the treatment.

  In the present embodiment, the amount of the basic compound used is desirably in the range of 0.1% by mass to 20% by mass of the aqueous dispersion of polymer particles (aggregate particles). Further, in the polymer particles obtained by the treatment with the basic compound, it is desirable that all the carboxyl groups form a salt structure. Usually, in the range of the use amount, the basic compound is a polymer particle. It is set to be excessive with respect to the amount of carboxyl groups.

  At this time, the pH of the aqueous dispersion of polymer particles is preferably 9 or more, and more preferably 11 or more. Although there is no restriction | limiting in particular in process temperature, you may heat to about 50 to 80 degreeC. Although there is no restriction | limiting in processing time, Usually, it is 0.5 hours or more and 10 hours or less. Furthermore, the concentration of the polymer particles (aggregate particles) during the treatment is not particularly limited, but is usually in the range of 1% by mass to 50% by mass. When the polymer particles settle during the treatment time, it is preferable to perform moderate stirring. After the treatment, the basic compound is removed by washing with water.

In the present embodiment, it is desirable to prepare the ink receiving particles by the method according to the above (Method 2) in that the aggregation operation is easy and reaggregation hardly occurs when the aggregate particles after neutralization are taken out. . Hereinafter, the aggregation / fusion process and the pulverization process in (Method 2) will be described.
In the aggregation / fusion, for example, first, various components are added and mixed as necessary to the aqueous dispersion of the polymer particles subjected to the neutralization treatment. The mixing method is not particularly limited, but a known mixing method can be used. For example, like a mixer, rotating a special stirring blade at a high speed to mix polymer particles in an aqueous medium, mixing with a rotor-stator shear force known as a homogenizer, and suspending by ultrasonic waves And other mechanical mixing methods.

In the aggregation / fusion, normal fine particles of non-crosslinked resin may be mixed as the resin fine particles to be used in addition to the polymer particles.
As said non-crosslinked resin, what was illustrated by the above-mentioned other resin can be utilized suitably.

Among these, in particular, when polyester is used to form a non-crosslinked polymer, it is effective for heat fixing. As the polyester, for example, a linear polyester resin made of a polycondensate containing bisphenol A and a polyvalent aromatic carboxylic acid as main monomer components can be preferably used.
Styrene-alkyl acrylate copolymers and styrene-alkyl methacrylate copolymers are also preferably used because they can easily control physical properties and can be easily mixed and dispersed with a magnetic powder described later.

In the present embodiment, the polymer particles and the like can be made into a fusion product by mixing such as stirring and then performing freeze-drying or the like as it is, but if necessary, heating during the mixing can be performed for aggregation and fusion. You may let them.
The fusion product can be obtained through a solid-liquid separation process such as filtration, and a washing process and a drying process as necessary. As the drying step, an arbitrary method such as a normal vibration type fluidized drying method, a spray drying method, a freeze drying method, or a flash jet method can be adopted. At this point, from the viewpoint of facilitating pulverization, it is desirable to adjust the moisture content of the fusion product after drying to 5% by mass or less.

Since the fusion product is obtained by agglomerating and fusing the polymer particles from a state of being gelled in water, the fusion product is often obtained as a lump rather than a particle. Therefore, in order to obtain ink receiving particles having a desired particle size, it is necessary to pulverize the massive fusion product.
The pulverization method is not particularly limited, and can be carried out using a pulverization means known per se, such as a mortar, ball mill, jet mill or the like.

The ink receiving particles (aggregate particles) after pulverization are in the form of particles, but the number average particle size is desirably 1.0 μm or more and 20.0 μm or less, and preferably 2.0 μm or more and 10.0 μm or less. More desirable.
When the volume average particle size is in the above range, high image quality is achieved. That is, if it is larger than 20.0 μm, a step in the height direction is generated between the portion where the particles are present and the portion where the particles are not present on the image surface, so that the smoothness of the image may be inferior. On the other hand, if the particle diameter is smaller than 1.0 μm, the handling property of the powder is lowered, and the powder may not be supplied to a desired position on the transfer body. Therefore, there are places where the ink receiving particles are not present on the image, and high-speed recording and high image quality may not be achieved.

  The volume average particle diameter of the ink receiving particles can be measured with Coulter Multisizer 3 (manufactured by Beckman Coulter, Inc.) after dispersing the ink receiving particles in distilled water and leaving them at 23 ° C. for 24 hours. it can.

The ink receiving particles of the present embodiment preferably have a BET specific surface area (N ₂ ) of 1 m ² / g or more and 750 m ² / g or less, more preferably 5 m ² / g or more and 600 m ² / g or less. still more preferably ^{10 m} 2 / g or more 400 meters ² / g or less. Within the above range, high-speed drying properties after ink reception tend to be excellent.

The ink receiving particles of the present embodiment preferably have a BET specific surface area (CO ₂ ) / BET specific surface area (N ₂ ) value of 1 or more and 50 or less, more preferably 1 or more and 40 or less. More preferably, it is 5 or more and 30 or less. When the amount is within the above range, the high-speed drying property after ink reception tends to be excellent.

Here, the BET specific surface area (N ₂ ) was measured using a beta soap automatic surface area meter (MODEL 4200, manufactured by Nikkiso Co., Ltd.).
Further, the BET specific surface area (CO ₂₎ was also measured similarly using beta soap automatic surface area meter (MODEL4200, manufactured by Nikkiso Co., Ltd.).

  Next, other additives for the ink receiving particles of this embodiment will be described. First, the ink receiving particles of the present embodiment preferably include a component that aggregates or thickens the components of the ink. When the component is contained, the recording material (for example, pigment or dye) contained in the ink is aggregated or the viscosity of the polymer is increased, so that the image quality and fixability are improved.

The component having such a function may be included as a functional group of the polymer particles constituting the ink receiving particles or may be included as a compound. Examples of the functional group include carboxylic acids, polyvalent metal cations, polyamines, and the like.
Moreover, as said compound, flocculants, such as an inorganic electrolyte, an organic acid, an inorganic acid, and an organic amine, are mentioned suitably.

  Examples of the inorganic electrolyte include alkali metal ions such as lithium ion, sodium ion and potassium ion, and aluminum ion, barium ion, calcium ion, copper ion, iron ion, magnesium ion, manganese ion, nickel ion, tin ion and titanium ion. , Polyvalent metal ions such as zinc ion, hydrochloric acid, odorous acid, hydroiodic acid, sulfuric acid, nitric acid, phosphoric acid, thiocyanic acid, and acetic acid, succinic acid, lactic acid, fumaric acid, fumaric acid, citric acid, salicylic acid, Examples thereof include organic carboxylic acids such as benzoic acid and salts with organic sulfonic acids.

  Specific examples include lithium chloride, sodium chloride, potassium chloride, sodium bromide, potassium bromide, sodium iodide, potassium iodide, sodium sulfate, potassium nitrate, sodium acetate, potassium oxalate, sodium citrate, potassium benzoate and the like. Alkali metal salts and aluminum chloride, aluminum bromide, aluminum sulfate, aluminum nitrate, sodium aluminum sulfate, potassium aluminum sulfate, aluminum acetate, barium chloride, barium bromide, barium iodide, barium oxide, barium nitrate, thiocyanate Barium acid, calcium chloride, calcium bromide, calcium iodide, calcium nitrite, calcium nitrate, calcium dihydrogen phosphate, calcium thiocyanate, calcium benzoate, calcium acetate, salicylic acid Lucium, calcium tartrate, calcium lactate, calcium fumarate, calcium citrate, copper chloride, copper bromide, copper sulfate, copper nitrate, copper acetate, iron chloride, iron bromide, iron iodide, iron sulfate, iron nitrate, oxalic acid Iron, iron lactate, iron fumarate, iron citrate, magnesium chloride, magnesium bromide, magnesium iodide, magnesium sulfate, magnesium nitrate, magnesium acetate, magnesium lactate, manganese chloride, manganese sulfate, manganese nitrate, manganese dihydrogen phosphate , Manganese acetate, manganese salicylate, manganese benzoate, manganese lactate, nickel chloride, nickel bromide, nickel sulfate, nickel nitrate, nickel acetate, tin sulfate, titanium chloride, zinc chloride, zinc bromide, zinc sulfate, zinc nitrate, thiocyanate Examples thereof include salts of polyvalent metals such as zinc acid and zinc acetate.

  Specific examples of the organic acid include arginic acid, citric acid, glycine, glutamic acid, succinic acid, tartaric acid, cysteine, oxalic acid, fumaric acid, phthalic acid, maleic acid, malonic acid, lysine, malic acid, and general Examples thereof include compounds represented by formula (1) and derivatives of these compounds.

Here, in the formula, X represents O, CO, NH, NR ₁ , S, or SO ₂ . R ₁ represents an alkyl group, and R ₁ is preferably CH ₂ , C ₂ H ₅ , or C ₂ H ₄ OH. R represents an alkyl group, and R is preferably CH ₂ , C ₂ H ₅ , or C ₂ H ₄ OH. In addition, R may be included in the formula or may not be included. X is preferably CO, NH, NR, or O, and more preferably CO, NH, or O. M represents a hydrogen atom, an alkali metal or an amine. M is preferably H, Li, Na, K, monoethanolamine, diethanolamine, triethanolamine or the like, more preferably H, Na, or K, and still more preferably a hydrogen atom. n is an integer of 3 to 7. n is preferably a case where the heterocyclic ring is a 6-membered ring or a 5-membered ring, and more preferably a 5-membered ring. m is 1 or 2, and l is an integer of 1 to 5. The compound represented by the general formula (1) may be a saturated ring or an unsaturated ring as long as it is a heterocyclic ring.

  Specifically, the compound represented by the general formula (1) has a furan, pyrrole, pyrroline, pyrrolidone, pyrone, pyrrole, thiophene, indole, pyridine, quinoline structure, and further has a carboxyl group as a functional group. Compounds. Specifically, 2-pyrrolidone-5-carboxylic acid, 4-methyl-4-pentanolide-3-carboxylic acid, furan carboxylic acid, 2-benzofuran carboxylic acid, 5-methyl-2-furan carboxylic acid, 2,5 -Dimethyl-3-furancarboxylic acid, 2,5-furandicarboxylic acid, 4-butanolide-3-carboxylic acid, 3-hydroxy-4-pyrone-2,6-dicarboxylic acid, 2-pyrone-6-carboxylic acid, 4-pyrone-2-carboxylic acid, 5-hydroxy-4-pyrone-5-carboxylic acid, 4-pyrone-2,6-dicarboxylic acid, 3-hydroxy-4-pyrone-2,6-dicarboxylic acid, thiophenecarboxylic Acid, 2-pyrrolecarboxylic acid, 2,3-dimethylpyrrole-4-carboxylic acid, 2,4,5-trimethylpyrrole-3-propionic acid, 3-hydroxy-2-yne Carboxylic acid, 2,5-dioxo-4-methyl-3-pyrroline-3-propionic acid, 2-pyrrolidinecarboxylic acid, 4-hydroxyproline, 1-methylpyrrolidine-2-carboxylic acid, 5-carboxy-1-methyl Pyrrolidine-2-acetic acid, 2-pyridinecarboxylic acid, 3-pyridinecarboxylic acid, 4-pyridinecarboxylic acid, pyridinedicarboxylic acid, pyridinetricarboxylic acid, pyridinepentacarboxylic acid, 1,2,5,6-tetrahydro-1-methyl Examples include nicotinic acid, 2-quinolinecarboxylic acid, 4-quinolinecarboxylic acid, 2-phenyl-4-quinolinecarboxylic acid, 4-hydroxy-2-quinolinecarboxylic acid, and 6-methoxy-4-quinolinecarboxylic acid. .

  The organic acid is preferably citric acid, glycine, glutamic acid, succinic acid, tartaric acid, phthalic acid, pyrrolidone carboxylic acid, pyrone carboxylic acid, pyrrole carboxylic acid, furan carboxylic acid, pyridine carboxylic acid, coumaric acid, thiophene carboxylic acid, Nicotinic acid, derivatives of these compounds, or salts thereof. More preferred are pyrrolidone carboxylic acid, pyrone carboxylic acid, pyrrole carboxylic acid, furan carboxylic acid, pyridine carboxylic acid, coumaric acid, thiophene carboxylic acid, nicotinic acid, derivatives of these compounds, or salts thereof. More preferred are pyrrolidone carboxylic acid, pyrone carboxylic acid, furan carboxylic acid, coumaric acid, or a compound derivative thereof, or a salt thereof.

  The organic amine compound may be any of primary, secondary, tertiary and quaternary amines and salts thereof. Specific examples include tetraalkylammonium, alkylamine, benzalkonium, alkylpyridium, imidazolium, polyamine, and derivatives or salts thereof. Specifically, amylamine, butylamine, propanolamine, propylamine, ethanolamine, ethylethanolamine, 2-ethylhexylamine, ethylmethylamine, ethylbenzylamine, ethylenediamine, octylamine, oleylamine, cyclooctylamine, cyclobutylamine, cyclohexane Propylamine, cyclohexylamine, diisopropanolamine, diethanolamine, diethylamine, di-2-ethylhexylamine, diethylenetriamine, diphenylamine, dibutylamine, dipropylamine, dihexylamine, dipentylamine, 3- (dimethylamino) propylamine, dimethylethylamine, Dimethylethylenediamine, dimethyloctylamine, 1,3-dimethylbutylamine, di Til-1,3-propanediamine, dimethylhexylamine, amino-butanol, amino-propanol, amino-propanediol, N-acetylaminoethanol, 2- (2-aminoethylamino) -ethanol, 2-amino-2- Ethyl-1,3-propanediol, 2- (2-aminoethoxy) ethanol, 2- (3,4-dimethoxyphenyl) ethylamine, cetylamine, triisopropanolamine, triisopentylamine, triethanolamine, trioctylamine, Tritylamine, bis (2-aminoethyl) 1,3-propanediamine, bis (3-aminopropyl) ethylenediamine, bis (3-aminopropyl) 1,3-propanediamine, bis (3-aminopropyl) methylamine, Bis (2-ethylhex ) Amine, bis (trimethylsilyl) amine, butylamine, butylisopropylamine, propanediamine, propyldiamine, hexylamine, pentylamine, 2-methyl-cyclohexylamine, methyl-propylamine, methylbenzylamine, monoethanolamine, laurylamine , Nonylamine, trimethylamine, triethylamine, dimethylpropylamine, propylenediamine, hexamethylesidiamine, tetraethylenepentamine, diethylethanolamine, tetramethylammonium chloride, tetraethylammonium bromide, dihydroxyethylstearylamine, 2-heptadecenyl-hydroxyethylimidazoline, Lauryldimethylbenzylammonium chloride, cetylpyridinium chloride Examples thereof include mouthride, stearamide methylbiridium chloride, diallyldimethylammonium chloride polymer, diallylamine polymer, and monoallylamine polymer.

  More preferably, triethanolamine, triisopropanolamine, 2-amino-2-ethyl-1,3-propanediol, ethanolamine, propanediamine, propylamine and the like are used.

Among these flocculants, polyvalent metal salts (Ca (NO ₃ ), Mg (NO ₃ ), Al (OH ₃ ), polyaluminum chloride, etc.) are preferably used.

  The flocculant may be used alone or in combination of two or more. The content of the flocculant is preferably 0.01% by mass or more and 30% by mass or less. More preferably, they are 0.1 mass% or more and 15 mass% or less, More preferably, they are 1 mass% or more and 15 mass% or less.

  The ink receiving particles of this embodiment desirably contain a release agent. This makes it possible to transfer and fix the ink receiving particles to the recording medium without oil. The release agent may be included in the organic resin, or the release agent particles may be combined with the organic resin particles.

  Examples of such release agents include low molecular weight polyolefins such as polyethylene, polypropylene, and polybutene; silicones having a softening point upon heating; fatty acids such as oleic acid amide, erucic acid amide, ricinoleic acid amide, and stearic acid amide Amides; plant waxes such as carnauba wax, rice wax, candelilla wax, tree wax, jojoba oil; animal waxes such as beeswax; montan wax, ozokerite, ceresin, paraffin wax, microcrystalline wax, Fischer-Tropsch wax, etc. Minerals and petroleum waxes, and modified products thereof. Among these, it is preferable to apply a crystalline compound.

  An external additive may be externally added to the ink receiving particles of this embodiment. By externally adding an external additive, it is possible to impart powder flowability of the ink receiving particles, chargeability / conductivity control, liquid absorption control, and the like. External additives include inorganic particles (colorless, light or white particles such as colloidal silica, alumina, calcium carbonate, zinc oxide, titanium oxide, tin oxide, cerium oxide, carbon black), resin particles (vinyl-based). Resin, polyester, silicone, etc.). These particles as external additives may be either hydrophobic or hydrophilic, and may be surface-treated with a coupling agent (for example, a silane coupling agent) to give a specific functional group (for example, an amino group or fluorine-based surface). Etc.) may be introduced. The particle size as the external additive is a volume average particle size of 5 nm to 100 nm, preferably 10 nm to 50 nm.

<Curable resin dispersion>
The curable resin dispersion of the present embodiment includes at least the ink receiving particles and the curable resin. Specifically, it is preferable to disperse ink receiving particles in a curable solution containing a curable resin.
By using the ink receiving particles of the present embodiment as a curable resin dispersion in which a curable resin is dispersed, for example, when an inkjet recording image is formed on a recording medium via the intermediate transfer body, the recording is performed on the intermediate transfer body. It is possible to improve the releasability of the formed image from the intermediate transfer member, and to obtain further excellent image fixability.

  Examples of the curable resin include an ultraviolet curable resin, an electron beam curable resin, and a thermosetting resin. The ultraviolet curable resin is easy to cure, has a faster curing speed than other resins, and is easy to handle. The electron beam curable resin does not require a polymerization initiator and is easy to control the coloration of the cured layer. The thermosetting resin is cured without requiring a large apparatus. In addition, curable resin is not restricted to these, For example, curable resin hardened | cured with moisture, oxygen, etc. can also be applied.

  Moreover, as a curable solution containing the said curable resin, it is good that it is low volatility or non-volatile in normal temperature (25 degreeC). Here, low volatility means that the boiling point is 200 ° C. or higher under atmospheric pressure. Nonvolatile means that the boiling point is 300 ° C. or higher under atmospheric pressure. The same applies hereinafter.

  Examples of the ultraviolet curable resin include acrylic resin, methacrylic resin, urethane resin, polyester resin, maleimide resin, epoxy resin, oxetane resin, polyether resin, and polyvinyl ether resin. The curable solution contains at least one of an ultraviolet curable monomer, an ultraviolet curable macromer, an ultraviolet curable oligomer, and an ultraviolet curable prepolymer. Moreover, the curable solution contains an ultraviolet polymerization initiator for allowing the ultraviolet curing reaction to proceed as necessary.

  Here, examples of the ultraviolet curable monomer include acrylate monomers, methacrylate monomers, epoxy monomers, oxetane monomers, vinyl ether monomers, and the like. The other macromers, oligomers, and prepolymers are those obtained by polymerizing these monomers at a predetermined polymerization degree, epoxy acrylates in which an acryloyl group or a methacryloyl group is added to an epoxy, urethane, polyester, or polyether skeleton, Examples thereof include urethane acrylate, polyester acrylate, polyether acrylate, urethane methacrylate, and polyester methacrylate.

  Examples of the ultraviolet polymerization initiator include radical photoinitiators such as acetophenone, benzophenone, benzoin ether, thioxanthone, acylphosphine oxide, peroxide, and titanocene compounds, aryldiazonium salts, diaryliodonium salts, and triarylsulfonium. Examples include salt.

Examples of the electron beam curable resin include acrylic resin, methacrylic resin, urethane resin, polyester resin, polyether resin, and silicone resin. The curable solution contains at least one of an electron beam curable monomer, an electron beam curable macromer, an electron beam curable oligomer, and an electron beam curable prepolymer.
Examples of the electron beam curable monomer, macromer, oligomer, and prepolymer include the same materials as the ultraviolet curable material.

  Examples of the thermosetting resin include an epoxy resin, a polyester resin, a phenol resin, a melamine resin, a urea resin, and an alkyd resin. The curable solution contains at least one of a thermosetting monomer, a thermosetting macromer, a thermosetting oligomer, and a thermosetting prepolymer. Further, a curing agent may be added during the polymerization. Further, the curable solution may contain a thermal polymerization initiator for causing the thermosetting reaction to proceed.

Here, examples of the thermosetting monomer include polyalcohols such as phenol, formaldehyde, bisphenol A, epichlorohydrin, cyanuric acid amide, urea and glycerin, acids such as phthalic anhydride, maleic anhydride, and adipic acid. It is done. The other macromers, oligomers, and prepolymers are those obtained by polymerizing these monomers at a predetermined polymerization degree, epoxy prepolymers, polyester prepolymers, and the like.
Examples of the thermal polymerization initiator include acids such as protonic acid / Lewis acid, alkali catalysts, and metal catalysts.

Further, the curable solution may contain water or an organic solvent for dissolving or dispersing the main components (monomer, macromer, oligomer, prepolymer, polymerization initiator, etc.) that contribute to the curing reaction. However, the ratio of the main component is preferably 30% by mass or more, more preferably 60% by mass or more, and further preferably 90% by mass or more.
Further, the curable solution may contain various color materials for the purpose of controlling the coloring of the cured layer.

  The viscosity of the curable solution is preferably 5 mPa · s or more and 10,000 mPa · s or less, more preferably 10 mPa · s or more and 1000 mPa · s or less, and further preferably 15 mPa · s or more and 500 mPa · s or less. The viscosity of the curable solution is preferably higher than the viscosity of the ink.

The curable resin dispersion of the present embodiment is configured by dispersing the ink receiving particles of the present embodiment in the curable solution.
As described above, since the curable solution contains the ink receiving particles, the ink liquid component (for example, water, aqueous solvent) is quickly taken into the ink receiving particles and the image is fixed. Color mixing at the boundary, image uniformity, and non-uniform transfer of ink due to pressure during transfer can be reduced.

The volume average particle size of the ink receiving particles contained in the curable resin dispersion is preferably 1 μm or more and 5 μm or less, and more preferably 2 μm or more and 4 μm or less. If the volume average particle size is less than 1 μm, the fixability may be deteriorated, and if it exceeds 5 μm, the image quality may be deteriorated.
The volume average particle diameter is measured by a laser diffraction particle size distribution measuring device, a Coulter counter, or the like.

  The content of the ink receptive particles in the curable resin dispersion is desirably in the range of 10% by mass to 90% by mass with respect to the entire curable resin dispersion, and is 20% by mass to 80% by mass. Is more preferred.

The ink receiving particles in the present embodiment are excellent in dispersibility in the curable solution, particularly when the polymer particles contain a resin containing a hydrophobic monomer structure. The evaluation of the dispersibility can be carried out by observing the particle state when a desired amount of ink receiving particles is put into a curable solution specifically prepared according to the application and stirred. In this case, a glass container having an opening area of about 1 cm ^{2 to} 10 cm ² is used as a container for storing the curable solution. In this evaluation, it is desirable that the ink receptive particles are well dispersed in water without being floated on the liquid surface or deposited on the container wall after stirring.

Further, the curable resin dispersion of the present embodiment can contain other additives. Specifically, a component that aggregates or thickens the components of the ink is suitable.
The component having this function may be included as a functional group of the resin constituting the ink receiving particles or may be included as a compound. Examples of the functional group include carboxylic acids, polyvalent metal cations, polyamines, and the like. Further, examples of the compound preferably include an aggregating agent such as an inorganic electrolyte, an organic acid, an inorganic acid, and an organic amine, and those exemplified in the above-described ink receiving particles can be used in the same manner.

Next, a recording method (recording apparatus) in which the ink receiving particles and the curable resin dispersion of the present embodiment are suitably used will be briefly described.
For example, the recording method (recording apparatus) is a recording method (recording apparatus) using an ink containing a recording material and the ink receiving particles of the present embodiment, and the step of receiving the ink in the ink receiving particles. (Receiving means) and a step (transfer means) of transferring ink receiving particles that have received ink to a recording medium. Further, it may further include a step (fixing means) for fixing the ink receiving particles transferred onto the recording medium.

  Specifically, for example, first, ink receiving particles are supplied in a layer form to an intermediate (intermediate transfer member) by a supply unit. Ink-receiving particles supplied in a layer form (hereinafter sometimes referred to as “ink-receiving particle layer”) are ejected and received by ink ejection means. The ink receiving particle layer that has received the ink is transferred from the intermediate to the recording medium by a transfer means. This transfer is selectively performed on the entire ink receptive particle layer or only the recording portion (ink receiving portion). Thereafter, if necessary, the ink receiving particle layer transferred to the recording medium is pressed (or heated / pressed) by a fixing means to be fixed. In this way, recording is performed with the ink receiving particles that have received the ink. Note that transfer and fixing may be performed simultaneously.

  As the recording medium, any of a permeable medium (for example, plain paper or coated paper) or a non-permeable medium (for example, a resin film) can be applied. The recording medium is not limited to these, and includes industrial products such as semiconductor substrates.

  EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited to these. In the examples, “part” and “%” represent “part by mass” and “% by mass”, respectively, unless otherwise specified.

<Measurement method for each characteristic value>
First, a method for measuring each characteristic value shown in the following examples will be described. Note that the measurement methods already described are omitted.
(Water absorption rate)
The water absorption was measured as follows according to JIS K7209 (1984).
First, the dried ink receiving particles are placed in a beaker. Ion exchange water is put here, and it is immersed at 23 ° C. for 24 hours. This particle dispersion is transferred to a centrifuge tube and centrifuged to sediment the particles. Remove the separated scum and absorb excess water remaining on the cake with filter paper. The mass M2 (mg) of the centrifuge tube at this time is weighed and then vacuum-dried at 40 ° C. for 24 hours, and the mass M1 (mg) of the centrifuge tube after drying is weighed. From these measured values, the water absorption C (%) was calculated according to the following formula (1).
Water absorption C (%) = [(M2-M1) / (M1-M3)] × 100 Formula (1)
(Here, M3 is the mass (mg) of the centrifuge tube.)

(Amount of acidic group)
First, polymer particles were weighed and placed in a capped test tube, 5 ml of DMF was added, and the mixture was dispersed for 1 hour using an ultrasonic stirrer. The total amount of the dispersion was collected in a conical beaker, and 0.1M ethanolic potassium hydroxide solution (manufactured by Wako Pure Chemical Industries, Ltd.) was added dropwise using phenolphthalein (manufactured by Wako Pure Chemical Industries, Ltd.) as an indicator.
Moreover, the blank experiment which does not use a polymer particle was also performed, and the acidic group amount (mmol / g) was computed from the difference according to the following Formula (2).

Acid group content = ((FE) × 0.1 × f) / W (2)
In the above formula (2), E is the potassium hydroxide solution dropping amount (ml) in the blank experiment, F is the sample potassium hydroxide solution dropping amount (ml), f is the factor of the potassium hydroxide solution, W is the polymer Each represents the weight (g) of the particles.

<Example 1>
(Manufacture of ink receiving particles)
In a 2 L three-necked flask equipped with a cooling tube, a nitrogen introduction tube, and a thermometer, 1000 parts of ion-exchanged water was added. To this, 6.0 parts of a surfactant (manufactured by Kao Corporation, Perex CS, solid content concentration: 75%) was added to obtain an aqueous phase. On the other hand, 1.5 parts of a polymerization initiator (manufactured by Wako Pure Chemical Industries, Ltd., potassium persulfate), 4.5 parts of styrene (manufactured by Wako Pure Chemical Industries, Ltd.), butyl methacrylate (manufactured by Wako Pure Chemical Industries, Ltd.) 18. 5 parts, mono-2- (methacryloyloxy) ethyl phthalate (Mitsubishi Rayon Co., Ltd., Acryester PA) 72.0 parts and divinylbenzene (Wako Pure Chemical Industries, Ltd., purity: 55%) 1.1 Parts were mixed to obtain a mixture (oil phase).
Subsequently, after making the inside of the flask system into a nitrogen atmosphere, this mixture was put into the aqueous phase.

  Thereafter, the system was heated to 60 ° C. and reacted for 8 hours. After completion of the reaction, the reaction solution was passed through a sieve having an opening of 20 μm. However, no aggregates of 20 μm or more remained on the sieve, and the whole amount passed. A part of the reaction product was taken and observed with a scanning electron microscope (manufactured by Keyence Corporation, VE7800). As a result, it was monodisperse polymer particles having an average particle diameter of 0.4 μm. After the obtained polymer particles were washed by centrifugation, a part of the polymer particles was collected and vacuum-dried, and the amount of acidic groups was measured and found to be 2.6 mmol / g.

Next, 600 parts of a 2% aqueous sodium hydroxide solution was added to the polymer particle slurry washed by centrifugation, and stirred at room temperature for 5 hours to neutralize carboxyl groups. The polymer particles thus neutralized were again washed by centrifugation, and then dried under vacuum at 60 ° C. for fusing.
The obtained fusion of polymer particles was put into a ball mill pot, pulverized with zirconia balls having a diameter of 10 mm, and classified to obtain ink receiving particles having a volume average particle diameter of 3 μm. The water absorption rate of the ink receiving particles was 500%.

(Preparation of curable resin dispersion)
-Polyurethane acrylate: 60 parts-1,6-hexanediol diacrylate: 20 parts-Methylbenzoylbenzoate (photopolymerization initiator): 5 parts The above was mixed with a roll mill to obtain a curable solution. 50 parts of the ink receiving particles were mixed with 100 parts of the curable solution to obtain a curable resin dispersion. In the preparation of this curable resin dispersion agent, the particles were well redispersed in water without floating on the water surface or depositing on the container wall surface, and the dispersibility was good.

(Evaluation)
-Ink for evaluation-
As the evaluation ink, the following black ink was prepared.
First, Cab-o-jet-300 (manufactured by Cabot) was treated with an ultrasonic homogenizer for 30 minutes, and then centrifuged (7000 rpm) for 20 minutes to obtain a pigment dispersion (carbon concentration: 12.8). %).

Next, the following components were sufficiently mixed and pressure filtered with a 1 μm filter to prepare a black ink.
-Pigment dispersion liquid: 40 parts-Glycerin: 20 parts-Surfactant (manufactured by NOF Corporation, Surfinol 465): 1.5 parts-Pure water: 35 parts

-Image formation-
The curable resin dispersion was applied on a fluorine-coated resin belt using a bar coater so as to have a film thickness of 10 μm to form an ink receiving particle layer. Characters and line images were printed using the black ink with a piezo recording head (resolution: 600 dpi).
Thereafter, the ink receiving particle layer is applied to the ink-receptive particle layer by a transfer device (having a structure in which the belt can be pressed by a pressure roll in which a steel pipe having a diameter of 30 mm is coated with a fluorine resin, and a pressing force against the belt: linear pressure 3 kgf / cm). The printed resin belt and art paper (OK Kanfuji, Oji Paper Co., Ltd.) are pressed and pressed, and UV irradiation is performed from the back of the resin belt with a metal halide lamp with a maximum lamp output of 1.5 kW. The layer was transferred.

-Evaluation of transferability-
At the time of transfer by the transfer device, the peelability of the ink receiving particle layer is evaluated by visually observing the residue on the resin belt after transfer, and when the residue is 10% or less in area per unit area The transferability was judged to be good, and if it was 10% or more, the transferability was judged to be poor.
The results are shown in Table 1.

-Evaluation of bleeding-
The character part in the obtained printed matter was visually evaluated. The evaluation criteria are as follows, and there is no practical problem if it is G1 or G2. The results are shown in Table 1.
G1: No bleeding of letters was observed.
G2: Some blurring of characters was observed, but there is no practical problem.
G3: The blur of letters was significant.

-Evaluation of fixability-
One minute after printing, the image portion was rubbed with a finger to determine the smudge of the finger and determine the fixing property. The evaluation criteria are as follows, and there is no practical problem if it is G1 or G2. The results are shown in Table 1.
G1: No dirt G2: Some dirt G3: There is dirt

<Example 2>
(Manufacture of ink receiving particles)
In Example 1, 4.5 parts of styrene (manufactured by Wako Pure Chemical Industries, Ltd.), 18.5 parts of butyl methacrylate (manufactured by Wako Pure Chemical Industries, Ltd.), mono-2- (methacryloyloxy) ethyl phthalate (Mitsubishi) Rayon Co., Ltd., Acryester PA (72.0 parts) and divinylbenzene (Wako Pure Chemical Industries, Ltd., purity: 55%) 1.1 parts styrene (Wako Pure Chemical Industries, Ltd.) 30 parts, methacrylic 40 parts of butyl acid (manufactured by Wako Pure Chemical Industries, Ltd.), 25.0 parts of mono-2- (methacryloyloxy) ethyl phthalate (manufactured by Mitsubishi Rayon Co., Ltd., acrylate ester PA) and divinylbenzene (Wako Pure Chemical Industries, Ltd.) ), Purity: 55%) The same treatment was carried out except that the content was changed to 2.2 parts to obtain monodisperse polymer particles having an average particle size of 0.3 μm. Furthermore, it processed like Example 1 and obtained the polymer fusion product.
The obtained fusion of polymer particles was put in a ball mill pot, pulverized with zirconia balls having a diameter of 10 mm, and classified to obtain ink receiving particles having a volume average particle diameter of 0.9 μm. The water absorption rate of the ink receiving particles was 150%.

Next, a curable resin dispersion was produced in the same manner as in Example 1, and the same evaluation was performed. In addition, the dispersibility of the particle | grains in the curable resin dispersion at this time was favorable.
The results are summarized in Table 1.

<Comparative Example 1>
Except for using 22.3 parts of methacrylic acid (product of Wako Pure Chemical Industries, Ltd.) instead of 72.0 parts of mono-2- (methacryloyloxy) ethyl phthalate in the production of the ink receiving particles of Example 1. Polymerization was carried out in the same manner as in Example 1.
An attempt was made to pass the reaction solution through a sieve having an opening of 20 μm, but a large amount of aggregates of 20 μm or more remained on the sieve. When a part of the reaction solution was taken and observed in the same manner with a scanning electron microscope (VE7800 manufactured by Keyence Corporation), it was amorphous polymer particles having a wide particle size distribution with a particle size of 10 μm to 100 μm. The amount of acidic groups in the polymer particles was approximately 0 mmol / g, and the water absorption rate of these particles was 100% or less.

Using the polymer particles, a curable resin dispersion was prepared in the same manner as in Example 1, and the same evaluation as in Example 1 was performed using this.
The results are summarized in Table 1.

<Comparative example 2>
  In the production of the ink receiving particles of Example 1, the monomer composition in the oil phase is 23.0 parts mono-2- (methacryloyloxy) ethyl phthalate, 40.0 parts styrene and butyl methacrylate, 32. Polymerization was carried out in the same manner as in Example 1 except that the amount was changed to 0 part.
  After completion of the reaction, the reaction solution was passed through a sieve having an opening of 20 μm. However, no aggregates of 20 μm or more remained on the sieve, and the whole amount passed. When a part was taken and observed with a scanning electron microscope (VE7800 manufactured by Keyence Corporation), it was a monodisperse polymer particle having a particle diameter of 0.3 μm. After the obtained polymer particles were washed by centrifugation, a part thereof was collected and vacuum-dried, and the amount of acidic groups was measured. As a result, it was 0.8 mmol / g, and the water absorption was 100% or less. .

  Using the polymer particles, a curable resin dispersion was prepared in the same manner as in Example 1, and the same evaluation as in Example 1 was performed using this.
  The results are summarized in Table 1.

<Comparative Example 3>
(Preparation of ink receiving particles)
- porous silica particles (inorganic porous particles: a volume average particle diameter of 30 nm, BET specific surface area ^{_{(N 2) 280m 2 / g}} ): 40 parts polyacrylic acid (partially crosslinked) resin particles (the organic resin particles: The volume average particle 400 nm in diameter, liquid absorbing resin, acid value 120 mgKOH / g, Tg = 40 ° C.): 60 parts, polyvinyl alcohol: 2.5 parts, polyallylamine: 2.5 parts

  After stirring and mixing the above composition (about 30 seconds with a sample mill), a small amount of aqueous sodium hydroxide solution was added and treated intermittently with a mechanofusion system to form composite particles. The particle size was measured for each intermittent driving condition, and was taken out when it reached about 2.2 μm.

  Furthermore, 1 part of silica, 1 part by weight of paraffin wax (OX-3215 / Nippon Seiwa Co., Ltd.) and 0.15 part of stearyl alcohol are added to 100 parts of the above particles in a sample mill, and stirred and mixed while heating. Ink-receiving particles having a volume average particle size of 2.2 μm were prepared. The water absorption rate of the ink receiving particles was 2000%.

A curable resin dispersion was prepared using the ink receiving particles in the same manner as in Example 1, and the same evaluation as in Example 1 was performed using this.
The results are summarized in Table 1.

  As described above, in the above-described examples, ink receiving particles having excellent dispersibility in a curable solution and excellent transferability, image quality, and fixability can be obtained. On the other hand, in the comparative example using the ink receptive particles of the present embodiment, some problem occurred.

Claims (8)

Including polymer particles, the polymer particles being 4.5 to 30 parts by mass of styrene, 18.5 to 40 parts by mass of butyl methacrylate, and mono-2- (methacryloyloxy) ethyl phthalate 25 A resin which is a copolymer of 0.07 parts by mass to 72.0 parts by mass and 1.1 parts by mass to 2.2 parts by mass of divinylbenzene , and the acidic group of the polymer particles is a base It is summed up
The ink receiving particles, wherein the polymer particles have a volume average particle size of 0.3 μm or more and 0.4 μm or less.   2. The ink receiving particles according to claim 1, wherein the ink receiving particles are constituted by at least one of aggregation and fusion of the polymer particles.   The acidic group amount of the polymer particles is 1.0 mmol / g or more and 3.5 mmol / g or less, and the volume average particle size of the particles composed of the polymer particles is 1.0 μm or more and 20 μm or less. The ink receiving particles according to claim 1 or 2.   The ink receiving particles according to any one of claims 1 to 3, wherein the water absorption is from 200% to 5000%. A curable resin dispersion comprising the ink receiving particles according to any one of claims 1 to 4 and a curable resin. The curable resin dispersion according to claim 5 , wherein the volume average particle diameter of the ink receiving particles is 1 μm or more and 5 μm or less. 4.5 parts by mass to 30 parts by mass of styrene, 18.5 parts by mass to 40 parts by mass of butyl methacrylate, 25.0 parts by mass to 72.0 parts by mass of mono-2- (methacryloyloxy) ethyl phthalate, Preparation of polymer particles containing a resin which is a copolymer of 1.1 parts by weight to 2.2 parts by weight of divinylbenzene and having a volume average particle size of 0.3 μm or more and 0.4 μm or less Process,
A neutralization step of neutralizing the acidic groups of the polymer particles with a base;
An aggregate particle forming step using the polymer particles as aggregate particles. The aggregate particle forming step includes
An aggregation / fusion process for aggregating / fusion of the polymer particles;
A pulverizing step of pulverizing the agglomerated and fused polymer particles;
The method for producing ink receiving particles according to claim 7 , wherein: