JP2009298917A - Composite particle and material for inkjet printing having the particle supported thereon - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide composite particles and a material for inkjet printing having the particles supported thereon, capable of overcoming the following problems: although, regarding improvement of the quality of inkjet printing, there are known techniques of forming one layer to a plurality of layers comprising inorganic particles such as silica and alumina on the surface of a material, techniques of utilizing a high water-absorptive resin, techniques of utilizing porous particles and so forth, there remain the problems in that the inorganic particles, because of high specific gravity, lead to the paper becoming heavy, the high water-absorptive resin swells, the porous particles take in even dyes inhibiting the printing density from becoming high, and so on. <P>SOLUTION: The composite particles are formed by bonding by ionic bond a cationic organic compound to organic polymer particles having a crosslinked structure and a 1-10 mmol/g salt type carboxylic group. The material for the inkjet printing has the above particles supported on the surface. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

The present invention relates to composite particles that contribute to an improvement in the speed and quality of ink jet printing and an ink jet printing material carrying the particles.

Ink-jet printing is possible without being in contact with the object to be printed, so it is not limited to flat materials such as paper, plastic sheets, fabrics, etc., and is widely used for printing on various materials such as building materials having uneven surfaces. It's being used. However, in inkjet printing, problems such as bleeding and back-through due to penetration of the ink into the print object and contamination due to slow drying with water-based inks are likely to occur, so printing is usually performed for the purpose of suppressing these problems. Some treatment is applied to the surface of the object.

For example, a technique (Patent Documents 1 and 2) in which a layer containing inorganic particles such as silica and alumina is formed on the material surface from one layer to a plurality of layers is disclosed. However, since inorganic particles have high specific gravity, paper becomes heavy. Alternatively, since many layers are formed, there are problems such as an increase in manufacturing cost. Moreover, although the technique (patent documents 3 and 4) using a superabsorbent resin and the technique (patent document 5) using a porous particle are also disclosed, a superabsorbent resin swells or a porous particle Has problems such as uptake of dyes and high printing density.
JP 2008-055696 A JP 2004-243719 A JP 2005-262765 A Japanese Patent Laid-Open No. 11-042851 JP 07-001835 A

As described above, the conventional techniques still have room for improvement. An object of the present invention is to provide composite particles capable of overcoming the above-described problems and an ink jet printing material carrying the particles.

As a result of diligent investigation to achieve the above-mentioned object, the present inventor applied composite particles obtained by combining a cationic organic compound to organic polymer particles having a specific structure to a substrate such as paper. The inventors have found that an ink jet printing material capable of giving good print quality can be obtained, and have reached the present invention.

That is, the present invention is achieved by the following means.
(1) Composite particles obtained by ion-bonding a cationic organic compound to organic polymer particles having a crosslinked structure and a salt-type carboxyl group of 1 to 10 mmol / g.
(2) The composite particles according to (1), wherein the water swelling degree of the organic polymer particles is 6 times or less.
(3) The composite particle according to (1) or (2), which is in the form of an emulsion.
(4) The composite particle according to any one of (1) to (3), wherein the organic polymer particle is a vinyl polymer, and a crosslinked structure is formed of a hydrazine compound or divinylbenzene.
(5) An ink jet printing material having the composite particles according to any one of (1) to (4) supported on the surface thereof.

The composite particle of the present invention is a composite of an organic polymer particle whose water swellability is suppressed by a crosslinked structure and a cationic organic compound. For this reason, both functions of absorption of the ink solvent and adsorption of the ink dye can be exhibited.

The present invention is described in detail below. The organic polymer particles employed in the present invention are composed of a polymer such as a polyamide-based polymer, a polyester-based polymer, or a vinyl-based polymer having a crosslinked structure and a salt-type carboxyl group of 1 to 10 mmol / g. be able to.

Examples of the counter ion constituting the salt-type carboxyl group of the organic polymer particles employed in the present invention include metal ions such as Li, Na, K, Mg, and Ca, and quaternary ammonium ions. There may be multiple types. If Na is selected as the counter ion, an effect of increasing the absorption amount of the ink solvent is obtained, and if K is selected, an effect of increasing the absorption speed of the ink solvent is obtained.

These salt-type carboxyl groups copolymerize monomers containing these salt-type carboxyl groups when polymerizing the polymers constituting the organic polymer particles, or contain nitrile groups or carboxylic acid esters. The monomer can be introduced by copolymerization and then hydrolysis.

Moreover, the quantity of a salt type carboxyl group is 1-10 mmol / g, Preferably it is 3-10 mmol / g, More preferably, it is 3-8 mmol / g. When the amount of the salt-type carboxyl group is less than 1 mmol / g, sufficient ink solvent absorbability cannot be obtained and bleeding may occur in the printing material. On the other hand, if it exceeds 10 mmol / g, the cross-linked structure is relatively reduced, and the organic polymer particles are swelled violently, so that the surface state of the material is deteriorated or the sharpness of printing is reduced. May cause problems.

The organic polymer particles employed in the present invention have a crosslinked structure. Since the polymers constituting the organic polymer particles are linked to each other by the cross-linked structure, it is possible to suppress swelling during ink solvent absorption. The degree of water swelling of the particles is desirably 6 times or less with respect to the dry volume of the particles from the viewpoint of maintaining the surface condition of the material and the sharpness of printing. The degree of water swelling can be controlled by adjusting the amount of salt-type carboxyl groups in the organic polymer particles, the type of counter ion, the amount of cross-linked structure introduced, and the like.

There are no particular limitations on the type of the above-mentioned crosslinked structure, for example, a crosslinked structure formed by adding a polyfunctional monomer such as divinylbenzene at the time of polymer polymerization, or hydrazine, ethylene glycol diglycidyl ether or the like after the polymer polymerization. Examples thereof include a crosslinked structure formed by reacting a polyfunctional compound.

In addition, as long as the target function is not inhibited, an H-type carboxyl group and other functional groups may exist in addition to the salt-type carboxyl group and the crosslinked structure described above.

The organic polymer particles employed in the present invention may be in the form of powder, but more preferably in the form of an emulsion. In the case of an emulsion, the composite particles of the present invention finally obtained can also be obtained in the form of an emulsion, and can be easily applied to a printing material. In addition, since the particle diameter is smaller than that in the powder form, the print quality can be made clearer.

Preferable examples of the organic polymer particles employed in the present invention described above include vinyl polymer particles having a crosslinked structure with divinylbenzene and a salt-type carboxyl group. The method for producing the particles is not particularly limited, and examples thereof include a method of graft polymerization of divinylbenzene and a vinyl monomer having a carboxyl group on an organic polymer. Divinylbenzene, a vinyl monomer having a carboxyl group, a vinyl monomer having a functional group that can be converted to a carboxyl group, and other vinyl monomers as necessary. The method of polymerizing is easy to use. Hereinafter, such a method will be described.

The amount of divinylbenzene used is not particularly limited, and may be set so that the intended function can be performed in consideration of water swellability and ink solvent absorbability. Thus, it is preferable that the content be 3 to 40% by weight. If the amount is 3% by weight or less, the resulting particles are swelled with water, and the surface condition may be deteriorated and the print quality may be deteriorated. On the other hand, when the amount is 40% by weight or more, the salt-type carboxyl group amount decreases, so that sufficient ink solvent absorbability may not be obtained.

Examples of the vinyl monomer having a carboxyl group include acrylic acid, methacrylic acid, maleic acid, itaconic acid, vinyl propionic acid, and lithium salts, sodium salts, potassium salts, ammonium salts, and the like of these acids. Examples of the vinyl monomer having a functional group that can be converted into acrylonitrile include acrylonitrile, methyl acrylate, and methyl methacrylate, and one or more of these can be used. In addition, when the vinyl-type monomer which has a functional group which can be converted into a carboxyl group is used, a carboxyl group is produced | generated by performing a hydrolysis process etc. to the particle | grains obtained by superposition | polymerization.

As the use amount of these monomers, from the viewpoint of obtaining good print quality, the salt type carboxyl group is 1 to 10 mmol / g, preferably 3 to 10 mmol / g, more preferably in the obtained particles. It is desirable to use so that it may become 3-8 mmol / g.

The polymerization method is not particularly limited, but it is preferable to use a suspension polymerization (pearl polymerization) or suspension precipitation polymerization method as a method for obtaining powdery particles, and a method for obtaining emulsion particles. Is preferably a method by emulsion polymerization.

As described above, when a vinyl monomer having a functional group that can be converted into a carboxyl group is employed as the polymerization composition, hydrolysis is performed after polymerization. The treatment conditions may be appropriately set so as to obtain the above carboxyl group amount, preferably 0.5 to 10% by weight, more preferably 1 to 5% by weight in an aqueous alkali metal salt solution, and a temperature of 50 to 120 ° C. The method of treating for 1 to 10 hours is industrially preferable. In such treatment, a salt-type carboxyl group to which a metal ion corresponding to the alkaline metal salt used is bonded is obtained. Examples of the alkaline metal salt used here include alkali metal hydroxides, alkaline earth metal hydroxides, alkali metal carbonates, etc., and the metal species include alkali metals such as Li, Na, and K, Mg, Mention may be made of alkaline earth metals such as Ca.

The salt-type carboxyl group of the particles having a crosslinked structure with divinylbenzene and a salt-type carboxyl group obtained by the above-described method is treated with a metal salt aqueous solution or an acid aqueous solution, if necessary, to bind to the carboxyl group. The type and amount of ions can be adjusted.

Another example of the organic polymer particles includes vinyl polymer particles in which a salt-type carboxyl group is introduced by subjecting acrylonitrile-based polymer particles to a crosslinking introduction treatment with a hydrazine compound and a hydrolysis treatment with an alkali metal salt. . Also in the particles, the amount of the crosslinked structure and the amount of the salt-type carboxyl group can be adjusted relatively easily.

The acrylonitrile polymer particles used as the raw material particles of the vinyl polymer particles include an acrylonitrile polymer containing 40% by weight or more, preferably 50% by weight or more, more preferably 80% by weight or more of acrylonitrile alone polymer or acrylonitrile. Particles formed by molecules can be employed. The monomer to be copolymerized with acrylonitrile is not particularly limited and may be appropriately selected. The acrylonitrile polymer particles may be in the form of a powder or an emulsion. Even in the case of an emulsion, the processing described later can be performed as it is.

Acrylonitrile polymer particles are subjected to a crosslinking introduction treatment with a hydrazine compound. In this treatment, the nitrile group of the acrylonitrile polymer particles and the amino group of the hydrazine compound react to form a crosslinked structure. , The nitrogen content in the fiber increases. This increase in nitrogen content is a measure of the degree of cross-linking, but is preferably 1 to 10% by weight when employed in the composite particles of the present invention.

As a method for adjusting the increase in nitrogen content to 1 to 10% by weight, the above-mentioned acrylonitrile-based polymer particles are contained in an aqueous solution having a hydrazine compound concentration of 5 to 60% by weight at a temperature of 50 to 120 ° C. within 5 hours. The method of treating with is industrially preferred.

The hydrazine-based compound used here is not particularly limited, and hydrazine derivatives such as hydrazine hydrate, hydrazine sulfate, hydrazine hydrochloride, hydrazine hydrobromide, hydrazine carbonate, ethylenediamine, guanidine sulfate, and guanidine hydrochloride. And compounds containing a plurality of amino groups such as guanidine phosphate and melamine.

The particles subjected to the cross-linking introduction treatment with the hydrazine compound may be subjected to an acid treatment after sufficiently removing the hydrazine compound remaining in the treatment. The acid used here is not particularly limited, and examples thereof include mineral acids such as nitric acid, sulfuric acid, and hydrochloric acid, and organic acids. The conditions for the acid treatment are not particularly limited, but the particles to be treated are immersed in an aqueous solution having an acid concentration of 3 to 20% by weight, preferably 7 to 15% by weight at a temperature of 50 to 120 ° C. for 0.5 to 10 hours. Examples are given.

The particles that have undergone the cross-linking introduction treatment with the hydrazine-based compound, or the particles that have undergone further acid treatment, are subsequently subjected to a hydrolysis treatment with an alkaline metal salt. By this hydrolysis treatment, the nitrile group remaining without being involved in the cross-linking introduction treatment with the hydrazine-based compound, or the residual nitrile group in the case of performing the acid treatment after the cross-linking introduction treatment, is partially acid-treated. The amide group generated by hydrolysis is converted into a salt-type carboxyl group to which a metal ion corresponding to the alkaline metal salt is bonded.

Examples of the alkaline metal salt used here include alkali metal hydroxides, alkaline earth metal hydroxides, alkali metal carbonates, etc., and the metal species include alkali metals such as Li, Na, and K, Mg, Mention may be made of alkaline earth metals such as Ca.

The amount of the salt-type carboxyl group produced by the hydrolysis treatment is 1 to 10 mmol / g, preferably 3 to 10 mmol / g, more preferably 3 to 8 mmol / g, from the viewpoint of obtaining good print quality. It is desirable that

The conditions for the hydrolysis treatment may be appropriately set so that a necessary amount of carboxyl groups is generated, but preferably 0.5 to 10% by weight, more preferably 1 to 5% by weight in an aqueous alkaline metal salt solution, A method of treating at a temperature of 50 to 120 ° C. for 1 to 10 hours is industrially preferable. The particles that have undergone the hydrolysis treatment may or may not have nitrile groups remaining. If the nitrile group remains, there is a possibility that a further function can be imparted using its reactivity.

The particles subjected to the hydrolysis treatment may be subjected to a treatment for adjusting a metal ion to be bonded to a carboxyl group using a metal salt as necessary. The salt used for the treatment may be any water-soluble salt of these metals, and examples thereof include hydroxides, halides, nitrates, sulfates and carbonates.

The organic polymer particles employed in the present invention described above form the composite particles of the present invention by ionic bonding with a cationic organic compound in a part of the salt-type carboxyl group of the particles.

Examples of cationic organic compounds employed in the present invention include cationic surfactants such as decyldimethylbenzylammonium chloride, dodecyldimethylbenzylammonium chloride, tetradecyldimethylammonium chloride, hexadecyldimethylammonium chloride, and octadecyldimethylammonium chloride. Or a polyalkylene polyamine such as polyethylene polyamine or polypropylene polyamine or a derivative thereof, a polymer of (meth) acrylate having a primary to tertiary amino group or a quaternary ammonium group, a primary to tertiary amino group or a quaternary ammonium group. (Meth) acrylamide derivative polymer, vinylamine polymer or derivative thereof, allylamine polymer or derivative thereof, diallylamine polymer, diallyl Tylamine polymer, diallyldimethylammonium chloride polymer, diallylamine-sulfur dioxide copolymer, diallyldimethylammonium chloride-sulfur dioxide copolymer, acrylamide-diallylamine copolymer, acrylamide-diallyldimethylammonium chloride copolymer, dicyandiamide-formalin Examples include polycondensates, dicyandiamide-diethylenetriamine polycondensates, epichlorohydrin-dimethylamine addition polymers, hydrolysates of acrylonitrile and N-vinylformamide copolymers, and cationic polymer compounds such as polyvinylamidine resins. You may use individually or in combination of multiple types.

In particular, a cationic organic compound having a quaternary ammonium group can be preferably used from the viewpoint of the strength of the binding force with the organic polymer fine particles and the acid dye employed in the present invention. It is more preferable to use a cationic polymer compound having the same.

The method for ionic bonding is not particularly limited, and examples thereof include a method of mixing particulate or emulsion organic polymer particles in an aqueous solution of a cationic organic compound. After mixing, it may be dried after dehydration or spray-dried, but if it is an emulsion-like organic polymer particle employed in the present invention, it will not cause aggregation precipitation even when mixed with a cationic organic compound. It is possible to obtain composite particles in an emulsion state and is easy to apply to printing materials.

The amount of the cationic organic compound ion-bonded to the organic polymer particle is determined in consideration of the amount of the functional group of the organic polymer particle or the cationic organic compound to be used or the type of printing material to be supported. For example, it may be set so as to give good print quality when it is carried on a printing material. For example, in the case of using emulsion organic polymer particles and acrylamide-diallyldimethylammonium chloride copolymer using divinylbenzene as described above, emulsion organic polymer particles and acrylamide-diallyldimethylammonium chloride copolymer aqueous solution. And the like in a solid content weight ratio of 10: 1.

The composite particles of the present invention obtained as described above have low water swellability while having water absorption, and have a cationic surface. In ink jet printing using an aqueous ink containing an acid dye, when the material carrying the composite particles is applied, the acid dye stays on the particle surface and water as a solvent is absorbed inside the particle. For this reason, clear ink jet printing becomes possible only by providing the composite particle layer on the material surface.

The ink jet printing material of the present invention can be obtained by supporting the composite particles of the present invention on the material surface. The material that can be used is not particularly limited as long as it can carry the composite particles of the present invention, and various materials such as paper, plastic sheet, fabric, wood, metal material, concrete, and glass can be used.

Examples of the method of supporting the composite particles of the present invention on the material surface include a method of applying or spraying the composite particles on the material if the composite particles are in the form of an emulsion. In addition, if the composite particles are in a powder form, a method of mixing with a binder and applying to a material can be exemplified.

In carrying the composite particles of the present invention, if necessary, in addition to the particles, conventionally known inorganic particles such as silica, alumina, kaolin, calcium carbonate, zeolite, etc., conductivity adjusting agent, antifoaming agent An anti-precipitation agent, an ultraviolet absorber, a light stabilizer, an antiseptic, an antioxidant, an anti-fading agent and the like may be added.

In some cases, a conventionally known layer such as a gloss layer on the upper side of the layer composed of the composite particles of the present invention or an ink solvent absorption layer on the lower side can be adopted. .

EXAMPLES Hereinafter, the present invention will be specifically described by way of examples. However, these are merely illustrative, and the gist of the present invention is not limited thereto. In addition, unless otherwise indicated, the part and percentage in an Example are shown on a weight basis.

(1) About 1 g of a salt-carboxyl group sufficiently dried sample is precisely weighed (W1 [g]), 200 ml of water is added thereto, and then 1 mol / l hydrochloric acid aqueous solution is added while heating to 50 ° C. The pH is adjusted to 2 and a titration curve is obtained with a 0.1 mol / l sodium hydroxide aqueous solution according to a conventional method. From the titration curve, the consumption amount of the aqueous sodium hydroxide solution consumed in the carboxyl groups (V1 [ml]) is determined, and the total carboxyl group amount (A1 [mmol / g]) is calculated by the following formula.

A1 [mmol / g] = 0.1 × V1 / W1

Separately, a titration curve was similarly obtained without adjusting to pH 2 by adding a 1 mol / l hydrochloric acid aqueous solution during the above total carboxyl group amount measurement operation, and the amount of H-type carboxyl groups (COOH) contained in the sample (A2 [Mmol / g]). From these results, the salt-type carboxyl group amount is calculated by the following formula.

Salt-type carboxyl group amount [mmol / g] = A1-A2

(2) Water swelling degree Aron Flock E (manufactured by MT Aqua Polymer Co., Ltd.) of 70% based on the solid content weight is added to the emulsion-like organic polymer particle sample to aggregate the particles. The obtained aggregated particles are dried and then pulverized. The pulverized particles are put into a graduated test tube with vibration so that the volume becomes about 1 cm ³ , and the particle volume is read with the scale of the test tube (V2 [cm ³ ]). Next, 10 cm ³ of water is added to the test tube, and then centrifuged at 8000 rpm for 3 minutes using a centrifuge (KS-8000, manufactured by Kubota Corporation). The test tube was gently taken out, the volume of the settled particles was measured (V3 [cm ³ ]), and the water swelling degree was calculated by the following formula.

Water swelling degree [times] = V3 / V2

(3) Ink drying printing A commercially available copy paper was rubbed over the image 10 seconds after printing, and the presence or absence of the ink transferred to the copy paper was evaluated according to the following evaluation criteria.
○: Almost not transferred Δ: Partially transferred ×: Transferd more than the state of “△”

(4) Sharpness of printing The sharpness of the printed image was evaluated by visual observation according to the following evaluation criteria.
○: The image is clear Δ: The image is slightly unclear ×: The image is unclear and blurry

[Example 1]
A reaction vessel is charged with 210 parts of ion-exchanged water and 2 parts of Eleminol MON-2 (manufactured by Sanyo Chemical Industries). Next, the temperature of the reaction vessel was raised to 60 ° C., and the monomer mixture solution consisting of 78 parts of ethyl acrylate, 5 parts of methyl methacrylate and 17 parts of divinylbenzene was added to the reaction vessel while stirring at 60 ° C. Polymerization was carried out by dripping an aqueous solution in which 6 parts were dissolved in 30 parts of water and an aqueous solution in which 0.5 parts of sodium pyrosulfite was dissolved in 30 parts of water over 3 hours and maintaining the same conditions for 2 hours after the completion of the dropwise addition. Do. The resulting emulsion was 21% solids. 400 parts of a 10% aqueous potassium hydroxide solution was added to 480 parts of the emulsion, and a hydrolysis reaction was carried out at 95 ° C. for 48 hours. Subsequently, the hydrolyzed emulsion was put in a cellulose semipermeable membrane, immersed in ion-exchanged water for desalting, and then ion-exchanged water was added to obtain emulsion-like organic polymer particles a having a solid content of 5%. Table 1 shows the amount of salt-type carboxyl groups and the degree of water swelling of the particles.

A 5% aqueous solution of the emulsion-like organic polymer particles a having a solid content of 5% obtained above and an acrylamide-diallyldimethylammonium chloride copolymer (PAS-J-81L manufactured by Nitto Boseki Co., Ltd.) in a ratio of 10: 1. To prepare emulsion-like composite particles A.

Emulsion-like composite particles A are applied to a commercially available copy paper so that the amount of adhesion is 10 g / m ² and dried, and then the image is printed by an ink jet printer (PIXUS ip2600 manufactured by Canon Inc.) to dry the ink. And the sharpness of printing were evaluated. The results are shown in Table 1.

[Example 2]
In the hydrolysis reaction of Example 1, emulsion-like organic polymer particles b having a solid content of 5% were obtained in the same manner as in Example 1 except that the concentration of the aqueous potassium hydroxide solution was 2.5%. Using the particles, emulsion-like composite particles B were prepared in the same manner as in Example 1, and the print quality of the copy paper coated with the particles was evaluated. The results are shown in Table 1.

[Example 3]
In Example 1, the composition of the monomer mixture was 92 parts ethyl acrylate, 5 parts methyl methacrylate, 3 parts divinylbenzene, and in the hydrolysis reaction, the concentration of the aqueous potassium hydroxide solution was 15%. Produced emulsion-like organic polymer particles c in the same manner as in Example 1. Using the particles, emulsion-like composite particles C were prepared in the same manner as in Example 1, and the print quality of the copy paper coated with the particles was evaluated. The results are shown in Table 1.

[Example 4]
490 parts of acrylonitrile, 16 parts of p-styrene sulfonic acid soda and 1181 parts of ion-exchanged water were charged in an autoclave, and di-tert-butyl peroxide was added as a polymerization initiator in an amount of 0.5% based on the total amount of monomers. Thereafter, it was sealed and then polymerized at a temperature of 150 ° C. for 23 minutes under stirring. After completion of the reaction, the mixture was cooled to about 90 ° C. while continuing stirring to obtain an emulsion of raw material particles β. Hydrazine was added to the emulsion of raw material particles β so that the concentration in the bath was 35%, and a crosslinking treatment was performed at 102 ° C. for 2.5 hours. Subsequently, sodium hydroxide was added so that the concentration in the bath was 10%, and a hydrolysis treatment was performed at 102 ° C. for 5 hours. The obtained emulsion was put in a cellulose tube, dialyzed and desalted with ion-exchanged water for 1 week, and then water was added to obtain emulsion-like organic polymer particles d having a solid content of 5%. Table 1 shows the amount of salt-type carboxyl groups and the degree of water swelling of the particles.

Emulsion-like composite particles D were prepared using the emulsion-like organic polymer particles d in the same manner as in Example 1, and the print quality of the copy paper coated with the particles was evaluated. The results are shown in Table 1.

[Comparative Example 1]
In the hydrolysis reaction of Example 1, emulsion-like organic polymer particles e having a solid content of 5% were obtained in the same manner as in Example 1 except that the concentration of the aqueous potassium hydroxide solution was 1.5%. Using the particles, emulsion-like composite particles E were prepared in the same manner as in Example 1, and the print quality of the copy paper coated with the particles was evaluated. The results are shown in Table 1.

[Comparative Example 2]
Emulsion organic polymer particles f were obtained in the same manner as in Example 1 except that the concentration of the aqueous potassium hydroxide solution was changed to 20% in Example 3. Using the particles, emulsion-like composite particles F were prepared in the same manner as in Example 1, and the print quality of the copy paper coated with the particles was evaluated. The results are shown in Table 1.

[Comparative Example 3]
The emulsion-like organic polymer particles a of Example 1 were applied to a commercially available copy paper so as to have an adhesion amount of 10 g / m ² , dried, and then printed with an ink jet printer (PIXUS ip2600 manufactured by Canon Inc.). The ink was dried and the print sharpness was evaluated. The results are shown in Table 1.

[Comparative Example 4]
An acrylamide-diallyldimethylammonium chloride copolymer (PAS-J-81L manufactured by Nitto Boseki Co., Ltd.) was applied to a commercially available copy paper so that the amount of adhesion was 10 g / m ² and dried, and then an inkjet printer (Canon An image was printed with PIXUS ip2600 manufactured by Co., Ltd., and the drying property of the ink and the sharpness of the printing were evaluated. The results are shown in Table 1.

As can be seen from Table 1, in Examples 1 to 4 employing the composite particles of the present invention, the drying property of the ink was good, and the printing was also clear. In contrast, Comparative Example 1 has too few salt-type carboxyl groups in the organic polymer particles, so that the ink solvent could not be sufficiently absorbed and the ink permeated into the paper itself. It is thought that it became inferior. In Comparative Example 2, since there are too many salt-type carboxyl groups in the organic polymer particles, it is considered that the water swelling of the particles became severe and the sharpness of printing was lowered.

In Comparative Example 3, since the cationic organic compound is not combined, the ink dye is likely to spread on the particle surface, and it is considered that the sharpness of printing is inferior. In Comparative Example 4, since only the cationic organic compound is used, the ink solvent is absorbed by the paper itself, and it is considered that the drying property of the ink and the sharpness of printing are inferior.

Claims (5)

Composite particles obtained by ion-bonding a cationic organic compound to organic polymer particles having a crosslinked structure and a salt-type carboxyl group of 1 to 10 mmol / g. The composite particle according to claim 1, wherein the organic polymer particles have a water swelling degree of 6 times or less. The composite particle according to claim 1, which is in an emulsion form. The composite particle according to any one of claims 1 to 3, wherein the organic polymer particle is a vinyl polymer, and the crosslinked structure is formed of a hydrazine compound or divinylbenzene. An ink jet printing material having the composite particles according to claim 1 supported on a surface thereof.