JPH11256087A - Production of ink for ink jet recording, and ink for ink jet recording produced thereby - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a process for producing an ink compsn. which is free of clogging due to a resin component observed when an ink compsn. contg. polymeric fine particles is used and which satisfies, at high levels, many requirements of an ink compsn. for ink jet recording and to provide an ink compsn. produced thereby. SOLUTION: The clogging due to a resin component is found to be caused by the fact that an org. solvent constituting an ink compsn. and, esp., a surfactant or penetrating agent which improves the penetrating properties of ink cause polymeric fine particles to swell to substantially increase the sizes of the particles, increasing the viscosity of ink and causing the particles to deposit in an ink head or other ink flow routes. The ink compsn. of the invention is produced by causing polymeric fine particles to swell by the contact with at least one org. solvent to such an equilibrium swelling state that the sizes of the polymeric fine paticles are in the range of 10-200 nm and then incorporating the swollen paticles into the compsn.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing an ink composition used in an ink jet recording method, an ink composition obtained by the method, and a method for producing polymer fine particles to be added to the ink composition. About the law.

2. Description of the Related Art Ink jet recording is a method of ejecting ink as fine droplets from fine nozzles to record characters and figures on the surface of a recording medium. A method of converting an electric signal into a mechanical signal using an electrostrictive element as an ink jet recording method, intermittently discharging ink stored in a nozzle head portion to record characters and symbols on the surface of a recording medium, a nozzle head A method of rapidly heating a part of the ink stored in the part very close to the discharge part to generate bubbles, intermittently discharging due to volume expansion due to the bubbles, and recording characters and symbols on the surface of the recording medium, etc. Has been put to practical use.

[0003] The ink used for such ink-jet recording is required to have characteristics such as good print drying properties, no printing bleeding, and uniform printing on various recording medium surfaces. Have been.

[0004] The ink composition for ink jet recording generally contains a colorant, water as a main solvent, and further contains an organic solvent. As the organic solvent, for example, glycol ether is used.
For example, Japanese Patent Publication No. 2-2907 discloses an ink composition using glycol ether as a wetting agent. JP-B-1-15542 discloses an ink composition used as a water-soluble organic solvent, and JP-B-2-3837 discloses an ink composition used as a dye dissolution accelerator.

[0005] Examples of ink compositions to which other organic solvents are added include the following. In order to improve the permeability, diethylene glycol monobutyl ether is disclosed in U.S. Pat. No. 5,156,675, and U.S. Pat.
JP-A No. 51966056 discloses the addition of Surfynol 465 (manufactured by Air Products), which is an acetylene glycol-based surfactant, and US Pat. No. 5,196,056 discloses the addition of both diethylene glycol monobutyl ether and Surfynol 465. And so on. Further, US Pat. No. 3,291,580 discloses that
The use of diethylene glycol mono-n-butyl ether, called butyl carbitol, is described in U.S. Pat.
No. 372 proposes to use ethers of diethylene glycol. JP-A-3-14811 proposes an ink containing 0.1 to 5% by weight of diethylene glycol monohexyl ether which is a glycol ether having low water solubility.

Further, as a coloring agent of the ink for ink jet recording, a water-soluble dye is often used because the main solvent is water. On the other hand, a pigment is also used as a coloring agent. I have. Since the pigment itself is unnecessary in water, an image formed by an ink using the pigment as a coloring agent has excellent water resistance. Many inks that use pigments as colorants have been studied and put into practical use at first, mainly to suppress ink permeability and to secure printing quality by suppressing ink wetting on the paper surface. . That is, the pigment remains on the recording medium surface,
The purpose is to secure image quality by increasing the image density.

On the other hand, since pigments are insoluble in water, if they remain on the surface of a recording medium, they may have poor abrasion resistance. Therefore, attempts have been made to increase the permeability of the ink even in the ink containing the pigment and to keep the pigment to some extent inside the recording medium. For example, as an ink using a combination of a glycol ether that imparts permeability and a pigment,
Discloses an example using triethylene glycol monomethyl ether in JP-A-56-147861. Further, in order to disperse the pigment in the ink composition, and to improve the abrasion resistance of the image, a resin component was added to obtain a stable dispersion of the pigment. Attempts to fix them have also been proposed. According to this method, there is obtained an advantage that bleeding of an image can be prevented at the same time as abrasion resistance. For example, Japanese Patent Application Laid-Open No. 8-85771
Japanese Patent Application Publication No. JP-A-2005-115122 discloses an ink containing a nonionic acrylic ester-based synthetic resin emulsion and an aqueous solvent in which these are dispersed. Here, when a penetrant such as glycol ether or a surfactant is added in order to increase the permeability of the ink composition while adding the polymer fine particles, a phenomenon that a stable dispersion system of the polymer fine particles is broken down occurs. Was observed. Therefore, utilization of a modified pigment having a hydrophilic group added to the pigment surface has been proposed. By using such a modified pigment, the advantages of adding the polymer fine particles and a penetrant or a surfactant can be simultaneously enjoyed.

However, according to the knowledge obtained by the present inventors, in the case of an ink composition containing a resin component, particularly, a resin component in the form of high-molecular fine particles, the resin component in the ink head or the ink flow path is not used. The occurrence of clogging was sometimes observed. In particular, it has been observed that this phenomenon is remarkable in an ink composition to which a surfactant or a penetrant that improves the permeability of the ink composition is added.

[0009]

SUMMARY OF THE INVENTION The present inventors have now found that clogging by the resin component may cause a surfactant or a penetrant to improve the permeability of the organic solvent constituting the ink composition, particularly the ink.
As a result, the polymer fine particles swell, and the fine particles are substantially enlarged to increase the viscosity of the ink or to adhere to the ink jet head or other ink flow paths. The present invention is based on this finding.

Accordingly, the present invention is free from clogging in an ink head or an ink flow path, which comprises both a surfactant or a penetrant for improving the permeability of ink and polymer fine particles, and further provides an ink jet recording medium. It is an object of the present invention to provide a method for producing an ink composition that satisfies various requirements required for an ink composition at a high level, and to provide an ink composition obtained by the method.

The method for producing an ink composition for ink jet recording according to the present invention is directed to an ink composition for ink jet recording comprising at least a colorant, one or more organic solvents, polymer fine particles, and water. Wherein the polymer fine particles are contacted with at least one kind of the organic solvent to swell, and in a state where the swelling reaches an equilibrium state, the diameter thereof is set in a range of 10 to 200 nm. The method comprises preparing molecular fine particles, and mixing the polymer fine particles, the colorant, the organic solvent, and the water to form an ink composition.

According to the ink composition obtained by the production method of the present invention, there is no problem such as clogging, and the permeability is very fast, so that high-speed printing is possible. It is possible to print with less bleeding, and furthermore, by using polymer fine particles, water resistance,
An image having excellent scratch resistance and light fastness and high color density can be realized.

[0013]

According to a first aspect of the manufacturing method of the ink composition (1) Preparation invention polymeric particles DETAILED DESCRIPTION OF THE INVENTION, a colorant, and one or more organic solvents, and the polymer fine particles, A method for producing an ink composition for ink jet recording comprising at least water. In the first step, the polymer fine particles are
Swelling by contacting with at least one organic solvent,
This is a step of preparing polymer fine particles having a diameter in the range of 10 to 200 nm in a state where the swelling has reached an equilibrium state.

According to the present inventors, it has been found that polymer fine particles have a property of swelling due to a surfactant, a penetrant such as glycol ether, or the like. In some cases, the diameter of the polymer fine particles increases by about several percent to several tens percent. Therefore, the particle size of the polymer particles added during the production of the ink composition may be different from the particle size of the polymer particles when the ink composition is actually used. Further, the swelling may change the viscosity of the ink composition. Therefore, in the present invention, polymer fine particles which have been swollen by being brought into contact with at least one of the organic solvents constituting the ink composition in advance and which have reached an equilibrium state are used. This aims to prevent physical properties such as the particle size of the polymer fine particles and the viscosity of the ink composition from changing after the production of the ink composition.

In the present invention, the organic solvent to be brought into contact with the fine polymer particles may be at least one of the organic solvents constituting the final ink composition. According to a preferred embodiment of the present invention, all the organic solvents are used in the ink composition. It is preferred that the organic solvent is brought into contact with the organic solvent contained at the addition ratio in the product. Further, a component constituting the ink composition other than the colorant may be prepared, and the component may be brought into contact with the polymer particles.

Although specific examples of the organic solvent will be described later, according to a preferred embodiment of the present invention, when the ink composition contains a glycol ether, the glycol ether is contacted with polymer fine particles to swell. Is preferred.

The temperature at which the polymer particles contact the organic solvent may be appropriately determined, but preferably does not change the properties of the material constituting the polymer particles. According to a preferred embodiment of the present invention, it is preferable that both are brought into contact at a temperature of about 5 to 80 ° C. Generally, at higher temperatures, swelling reaches equilibrium in a short time. However, when both are contacted at a temperature higher than room temperature, when the system is returned to room temperature, the particle size of the polymer fine particles may fluctuate. Therefore, the term "polymer fine particles having a diameter in the range of 10 to 200 nm" is preferably measured at room temperature, more specifically, at an ambient temperature when the printer is actually used. . The ambient temperature when the printer is actually used is generally in the range of 5 to 45C.

In the present invention, it is most preferable to use polymer fine particles whose swelling has reached an equilibrium state, but most of the polymer fine particles are added to the ink composition after being brought into contact with the above temperature for about 24 hours. Then, the properties and physical properties of the ink composition are not changed in the ink composition, and problems such as clogging do not occur. Therefore, in the present invention, the term "equilibrium state of swelling" means that after being added to the ink composition, the properties and properties of the ink composition are not changed, and the ink composition is swollen to such an extent that it does not cause problems such as clogging. Means what was done.

In the present invention, when swelling due to contact with an organic solvent reaches an equilibrium state, the swelling is 10 to 200 nm.
Polymer fine particles having a diameter of Here, after swelling, only polymer fine particles within the above range can be selected and used by a filter or the like. Further, according to another preferred embodiment of the present invention, by controlling the material and the initial particle size of the polymer fine particles, when the swelling reaches an equilibrium state, the diameter of all the particles is in the range of 10 to 200 nm. It may be manufactured as such. According to a preferred embodiment of the present invention, the lower limit of the diameter of the polymer fine particles in an equilibrium state is 10 n.
m, preferably 20 nm, and the upper limit thereof is 200 nm, preferably 150 nm. When the diameter of the polymer particles in the equilibrium state is within the above range, an ink composition having excellent abrasion resistance, no clogging of nozzles, and excellent continuous printing characteristics can be obtained. In particular, when the ink ejection mechanism based on the response of the electrostrictive element is used, the above advantage can be favorably enjoyed. This is because the polymer particles may be deteriorated by heat in a mechanism that generates bubbles by heating the vicinity of the nozzle.
Furthermore, the ink composition according to the present invention is used in combination with a head having a tip of a nozzle where eutectoid plating of polytetrafluoroethylene and metal is performed,
The above advantages can be preferably enjoyed.

The diameter of the fine polymer particles may be measured by various methods, but is preferably measured by a particle size measuring device using laser light. The diameter of the polymer fine particles may be measured in glycol ether, but is more preferably measured in a solution having the same composition as the ink and excluding components such as pigments that hinder measurement of the particle diameter. Alternatively, the ink composition may be measured after being separated from the ink composition by precipitation or the like using a component such as a colorant that interferes with the measurement of the particle size or a chemical reaction, or after being removed by a method such as chromatography.

In the present invention, the polymer fine particles are added to fix the pigment component on the surface of the recording medium as described above, improve the abrasion resistance of the image, and further prevent bleeding. The material of the polymer fine particles is not particularly limited as long as this object can be achieved. Further, the method according to the present invention can be preferably applied as long as the fine particles are made of a polymer material which swells with a penetrant such as glycol ether or a surfactant.

As the substance forming the polymer fine particles, in addition to styrene, tetrahydrofurfuryl acrylate and butyl methacrylate, (α, 2, 3 or 4) -alkylstyrene, (α, 2, 3 or 4) -alkoxystyrene, 3,4-dimethylstyrene, α-phenylstyrene, divinylbenzene, vinylnaphthalene, dimethylamino (meth) acrylate, dimethylaminoethyl (meth) acrylate, dimethylaminopropylacrylamide, N, N-dimethylaminoethylacrylate, acryloylmorpholine , N, N-dimethylacrylamide, N-isopropylacrylamide, N, N
-Diethylacrylamide, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, ethylhexyl (meth) acrylate, other alkyl (meth) acrylates, methoxydiethylene glycol (meth) acrylate, ethoxy, propoxy, butoxy groups Diethylene glycol or polyethylene glycol (meth) acrylate, cyclohexyl (meth) acrylate, benzyl (meth) acrylate, phenoxyethyl (meth) acrylate, isobonyl (meth) acrylate, hydroxyalkyl (meth) acrylate, (meth) acrylamide, (mono) , Di, tri, tetra, poly) ethylene glycol di (meth) acrylate, 1,4-butanediol, 1,
5-pentanediol, 1,6-hexanediol,
(Meth) acrylates such as 1,8-octanediol and 1,10-decanediol, trimethylolpropane tri (meth) acrylate, glycerin (di, tri)
Examples thereof include (meth) acrylate, di (meth) acrylate of ethylene oxide adduct of bisphenol A, neopentyl glycol di (meth) acrylate, pentaerythritol tetra (meth) acrylate, and dipentaerythritol hexa (meth) acrylate.

The production of polymer fine particles can be carried out, for example, by known emulsion polymerization. That is, it can be obtained by emulsion polymerization of an unsaturated vinyl monomer which is a monomer capable of forming the above polymer in water in the presence of a polymerization catalyst and an emulsifier.

The diethylene glycol monobutyl ether which is the same as that used in the ink as other components to be added is the above-mentioned triethylene glycol monobutyl ether, (mono, di) propylene glycol monobutyl ether, (di, tri) ethylene glycol mono (pentyl, Hexyl) ether, propylene glycol (mono, di) ethylene glycol mono (butyl, pentyl,
Hexyl) ether, ethylene glycol (mono, di)
At least one selected from propylene glycol mono (butyl, pentyl, hexyl) ether, and a surfactant, 2,4,7,9-tetramethyl-5-decyne-4,7-
Diol, 3,6-dimethyl-4-octyne-3,6-
Diols, ethylene oxide and / or propylene oxide adducts of 2,4,7,9-tetramethyl-5-decyne-4,7-diol and / or 3,6-dimethyl-4-octyne-3,6-diol Ethylene oxide and / or propylene oxide adducts could be used.

From another viewpoint of the first step of the present invention, this step comprises a step of adding a single or two or more organic solvents to an ink composition for use in ink-jet recording. It is considered a method for producing molecular fine particles. Therefore, according to another aspect of the present invention, there is provided a method for producing polymer fine particles used in addition to an ink composition for inkjet recording, comprising one or more organic solvents, the method comprising: Polymer fine particles are prepared, and the polymer fine particles are brought into contact with at least one kind of the organic solvent to swell, and when the swelling reaches an equilibrium state, the polymer fine particles have a diameter in the range of 10 to 200 nm. And obtaining Further, according to the present invention, there is also provided a polymer fine particle obtained by this method and containing one or more organic solvents and used by adding to an ink composition for inkjet recording.

(2) Preparation of Ink Composition The second step of the method according to the present invention comprises mixing the polymer fine particles prepared as described above, a colorant, an organic solvent, and water with an ink. This is a step of forming a composition. This step may be the same as the production of the ink composition containing the polymer particles, except that the polymer particles prepared as described above are used. That is, these components are mixed or dispersed, and then, if necessary, filtered through a filter to obtain an ink composition.

(A) Colorant In the present invention, the colorant may be a dye or a pigment. As the dye, use various dyes which are usually used for inkjet recording, such as direct dye, acid dye, food dye, basic dye, reactive dye, disperse dye, vat dye, soluble vat dye, and reactive disperse dye. Can be.

As pigments, inorganic pigments and organic pigments can be used. As the inorganic pigment, in addition to titanium oxide and iron oxide, carbon black produced by a known method such as a contact method, a furnace method, and a thermal method can be used. Examples of organic pigments include azo pigments (including azo lakes, insoluble azo pigments, condensed azo pigments, chelated azo pigments, etc.) and polycyclic pigments (for example, phthalocyanine pigments, perylene pigments, perinone pigments, anthraquinone pigments, quinacridone pigments, dioxazines) Pigments, thioindigo pigments, isoindolinone pigments,
Quinofurarone pigments, dye chelates (eg, basic dye chelates, acid dye chelates, etc.), nitro pigments, nitroso pigments, aniline black and the like can be used.

According to a preferred embodiment of the present invention, these pigments are preferably added to the ink as a pigment dispersion obtained by dispersing in an aqueous medium with a dispersant or a surfactant. As a preferred dispersant, a dispersant commonly used for preparing a pigment dispersion, for example, a polymer dispersant can be used. Further, the polymer fine particles prepared as described above can be used as a dispersant for preparing a pigment dispersion. It will be apparent to those skilled in the art that the dispersant and surfactant contained in this pigment dispersion will also function as the dispersant and surfactant of the ink composition.

Further, according to a preferred embodiment of the present invention, the surface is dispersed by a surface treatment such that at least one functional group of a carbonyl group, a carboxyl group, a hydroxyl group, or a sulfone group or a salt thereof is bonded. Preference is given to using pigments which can be dispersed and / or dissolved in water without agents. Specifically, such a pigment can be obtained by grafting a functional group or a molecule containing a functional group to the surface of carbon black by a physical treatment such as vacuum plasma or a chemical treatment. In the present invention, the functional groups grafted to one carbon black particle may be single or plural. The type and the degree of the functional group to be grafted may be appropriately determined in consideration of the dispersion stability in the ink, the color density, the drying property on the front surface of the inkjet head, and the like.

In the present invention, the state where the pigment is stably present in water without a dispersant is referred to as “dispersion and / or dissolution”. In many cases, it is difficult to clearly distinguish whether a substance is dissolved or dispersed.
In the present invention, as long as the pigment can be stably present in water without a dispersant, such a pigment can be used irrespective of whether the pigment is dispersed or dissolved. Therefore, in this specification, a pigment that can be stably present in water without a dispersant is sometimes referred to as a water-soluble pigment, but this does not mean that a pigment in a dispersed state is excluded.

According to a preferred embodiment of the present invention, it is preferably used as a pigment dispersion having an average particle diameter of 50 to 150 nm and a degree of dispersion of 10 or less.

The pigment preferably used in the present invention can be obtained, for example, by the method described in JP-A-8-3498. In addition, a commercially available product can be used as the pigment, and a preferable example is MicroJet CW1 manufactured by Orient Chemical Industries, Ltd.

The amount of the pigment added to the ink composition is 2 to 1
It is preferably 0% by weight, more preferably about 5 to 8% by weight.

(B) Organic solvent and water In the present invention, water is the main solvent. As the water, pure water such as ion-exchanged water, ultrafiltration water, reverse osmosis water, or distilled water, or ultrapure water can be used. In addition, it is preferable to use water sterilized by ultraviolet irradiation, addition of hydrogen peroxide, or the like, since the generation of mold and bacteria can be prevented when the ink composition is stored for a long period of time.

The organic solvent used in the present invention forms a main solvent with water, has compatibility with water, and does not have an unfavorable interaction with other components in the ink composition. There is no particular limitation as long as

According to a preferred embodiment of the present invention, as the organic solvent, ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, propylene glycol, or the like is used in order to suppress drying of the ink composition on the front surface of the nozzle of the ink jet recording head. Dipropylene glycol, tripropylene glycol, polyethylene glycol having a molecular weight of 2000 or less,
1,3-propylene glycol, isopropylene glycol, isobutylene glycol, 1,4-butanediol, 1,3-butanediol, 1,5-pentanediol, 1,6-hexanediol, glycerin, thiodiglycol, mesoerythritol , Pentaerythritol and the like can be added. Glycerin,
1,5-pentanediol, diethylene glycol, or thiodiglycol, and a mixture thereof can appropriately control the viscosity of the ink composition and can effectively prevent nozzle clogging.

When the colorant is a pigment and the ink composition contains a surfactant described below, at least glycerin, (mono, di, tri, tetra, poly) ethylene glycol, (mono) , Di, tri, tetra) propylene glycol, (propane, butane, pentane, hexane) diol and thiodiglycol. By these additions, an ink composition with less nozzle clogging can be obtained. According to another preferred embodiment of the present invention, the water-soluble organic solvent that can be added to the ink composition according to the present invention includes alkyl alcohols having 1 to 4 carbon atoms such as ethanol, methanol, butanol, propanol and isopropanol. , Glycol ethers,
Formamide, acetamide, dimethyl sulfoxide,
Sorbit, sorbitan, acetin, diacetin, triacetin, sulfolane and the like. The addition of these organic solvents improves the solubility of other components in the ink composition in the ink composition, further improves the permeability to a recording medium, such as paper, and further effectively prevents nozzle clogging. This is preferable because it can be prevented.

The addition amount of these organic solvents may be determined as appropriate, but according to a preferred embodiment of the present invention, the amount is preferably about 3 to 20% by weight. When the amount of the organic solvent is within this range, clogging of the nozzle can be effectively prevented. Further, even if the nozzle is once clogged, the advantage is obtained that the clogging can be eliminated by supplying a fresh ink composition.

According to a preferred embodiment of the present invention, glycol ether is preferably added as the organic solvent. The addition of the glycol ether improves the permeability of the ink composition into a recording medium such as paper, and as a result, bleeding is reduced and print quality can be improved. In particular, the glycol ether is (di or tri) ethylene glycol monobutyl ether, (mono or di) propylene glycol monobutyl ether, (di or tri) ethylene glycol mono (pentyl or hexyl) ether, propylene glycol (mono or di) ethylene glycol It is preferably at least one selected from the group consisting of mono (butyl, pentyl or hexyl) ether and ethylene glycol (mono or di) propylene glycol mono (butyl, pentyl or hexyl) ether. The addition amount of these glycol ethers is preferably about 5 to 20% by weight.

According to a further preferred embodiment of the present invention, the glycol ether is (mono or di) propylene glycol monobutyl ether, (di or tri) ethylene glycol mono (pentyl or hexyl) ether, propylene glycol (mono or di) ethylene. It is preferable to use glycol mono (butyl, pentyl, or hexyl) ether or ethylene glycol (mono or di) propylene glycol mono (butyl, pentyl, or hexyl) ether alone or in combination of two or more. By using these, the permeability to paper such as recycled paper is improved, and bleeding can be further reduced. However, since these glycol ethers have low water solubility, a large amount thereof may cause phase separation at room temperature. In such a case, the addition amount of the low water-soluble glycol ether can be increased by adding a highly water-soluble glycol ether or an organic solvent. According to a preferred embodiment of the present invention, it is preferable to use (di, tri) ethylene glycol monobutyl ether as such a highly water-soluble glycol ether.

(C) Other Components In the present invention, the ink composition may contain other components in addition to the colorant, the fine polymer particles, the organic solvent, and water.

For example, the ink composition can include a surfactant. According to a preferred embodiment of the present invention, particularly preferred surfactants are 2,4,7,9-tetramethyl-5-decyne-4,7-diol and 3,6-dimethyl-4-octyne-3,6. -Diol, 2,4,7,9-
An ethylene oxide and / or propylene oxide adduct of tetramethyl-5-decyne-4,7-diol,
Alternatively, it is preferable to use ethylene oxide and / or propylene oxide adducts of 3,6-dimethyl-4-octyne-3,6-diol alone or in combination. By adding these surfactants, the penetration of the ink into a recording medium such as paper can be improved in the same manner as in the case of glycol ether, whereby the bleeding can be reduced.

According to a preferred embodiment of the present invention,
7,9-tetramethyl-5-decyne-4,7-diol, 3,6-dimethyl-4-octyne-3,6-diol, 2,4,7,9-tetramethyl-5-decyne-4,
Ethylene oxide and / or propylene oxide adduct of 7-diol, or ethylene oxide and / or 3,6-dimethyl-4-octyne-3,6-diol
Alternatively, when a propylene oxide adduct is added, it is preferable that the composition further comprises a surfactant selected from the group consisting of an anionic surfactant, a nonionic surfactant, and an amphoteric surfactant having an HLB of 8 or more. . By adding these additional surfactants, the solubility of the surfactants in the ink composition can be improved.

Preferred examples of the amphoteric surfactant include betaine lauryldimethylaminoacetate, 2-alkyl-N
-Carboxymethyl-N-hydroxyethylimidazolinium betaine, coconut oil fatty acid amidopropyldimethylaminoacetic acid betaine, polyoctylpolyaminoethylglycine, imidazoline derivatives and the like. Preferred examples of the anionic surfactant include a phosphoric acid (mono, di, or tri) ester salt of polyethylene glycol octylphenyl ether, a phosphoric acid (mono, di, or tri) ester salt of polyethylene glycol nonylphenyl ether, and polyethylene glycol octyl ether. Phosphoric acid (mono, di, or tri) ester salt, polyethylene glycol nonyl ether phosphoric acid (mono, di, or tri) ester salt, polyethylene glycol lauryl phenyl ether phosphoric acid (mono, di, or tri) ester salt, polyethylene glycol Phosphoric acid (mono, di, or tri) ester salts of lauryl ether, and phosphoric acid (mono, di,
Or tri) ester salts, phosphoric acid (mono, di, or tri) ester salts of polyethylene glycol alkyl ethers, and boric acids based on the above-mentioned phosphate surfactants;
Other inorganic salt-based surfactants such as silicic acid-based surfactants can be used.

Preferred examples of the nonionic surfactant include polyoxyethylene nonyl phenyl ether, polyoxyethylene octyl phenyl ether, polyoxyethylene dodecyl phenyl ether, polyoxyethylene alkyl allyl ether, polyoxyethylene oleyl ether, and polyoxyethylene oleyl ether. Ethers such as ethylene lauryl ether, polyoxyethylene alkyl ether, polyoxyalkylene alkyl ether, polyoxyethylene oleic acid, polyoxyethylene oleate, polyoxyethylene distearate, sorbitan laurate, sorbitan monostearate, and sorbitan Monooleate, sorbitan sesquiolate,
Examples thereof include ester-based surfactants such as polyoxyethylene monooleate and polyoxyethylene stearate, and fluorinated surfactants such as fluoroalkyl esters and perfluoroalkylcarboxylates.

It is preferable that the total amount of these water-soluble surfactants is 3% by weight or less. When the surfactant is in the range of this addition amount, foaming is small,
An ink composition having stable characteristics and good image quality can be obtained.

Further, in the present invention, the ink composition comprises:
It may be preferred that the pH is on the alkaline side. In particular, when a surface-treated pigment is used, or when a direct dye or an acid dye is used, the coloring material may aggregate or decompose on the acidic side. Preferably, the pH is in the range of 7.5 to 11 at 5 to 45 ° C. The pH on the alkali side is preferably realized by adding an organic amine and / or an inorganic alkali, and more preferably, simultaneous addition of an organic amine and an inorganic alkali, which can be expected to have a buffering action. Specific examples of organic amines include (mono, di, or tri) ethanolamine,
(Mono, di, or tri) propanolamine, (mono or di) methylethanolamine, ammonia, tetramethylammonium. Further, specific examples of the inorganic alkali include lithium hydroxide, sodium hydroxide, and potassium hydroxide. When a carboxyl group is present on the surface of the surface-treated pigment or the polymer fine particles, it is preferable that the inorganic alkali is a monovalent metal because aggregation of the pigment or the polymer fine particles can be prevented.

Further, in the present invention, a saccharide can be added to prevent drying of the ink at the nozzle. Preferred examples of the saccharide include monosaccharides and polysaccharides, and specific examples thereof include glucose, mannose, fructose, ribose, xylose, arabinose, lactose, galactose, aldonic acid, glucitolose, maltose, cellobiose, and sucrose. Trehalose, maltotriose, alginic acid and its salts, cyclodextrins, and celluloses. The added amount of the saccharide is preferably about 3 to 20% by weight. Among others, glucose, mannose, fructose, ribose, xylose, arabinose, lactose, galactose, aldonic acid, glucitolose, maltose, cellobiose, sucrose, trehalose,
A more preferable addition amount of maltotriose or the like is 5 to 10% by weight. Since the viscosity of the ink composition tends to increase by the addition of alginic acid and its salts, cyclodextrins, and celluloses, it is preferable to reduce the amount of addition.

In the present invention, the ink composition comprises a preservative, an antioxidant, a conductivity adjuster, a pH adjuster, a viscosity adjuster, a surface tension adjuster, an oxygen absorber, an agent for preventing nozzle clogging, and the like. It can comprise additives. Preservative·
Examples of fungicides include sodium benzoate, sodium pentachlorophenol, 2-pyridinethiol-1
-Sodium oxide, sodium sorbate, sodium dehydroacetate, 1,2-dibenzisothiazoline-
3-one (Proxel CRL, Proxel B from ICI)
DN, proxel GXL, proxel XL-2, proxel TN) and the like.

(3) Ink Composition According to another aspect of the present invention, there is provided an ink composition obtained by the above-described method for producing an ink composition and used in an ink jet recording method. According to a preferred embodiment of the present invention, the surface tension of the ink composition is preferably about 20 to 40 mN / m at 5 to 45 ° C. The viscosity of the ink composition is 2 to 1 at 5 to 45 ° C.
0 mPa. It is preferably s.

The ink composition according to the present invention is preferably used in an ink jet recording method. According to a preferred embodiment of the present invention, it is preferably used in an ink jet recording method using an ink jet head having a mechanism based on the response of an electrostrictive element. Since the polymer fine particles may cause a chemical change by heat, it is preferable to use the polymer fine particles in an ink jet recording method using an electrostrictive element without using a heating means.

According to a preferred embodiment of the present invention, the ink composition according to the present invention has a nozzle opening front surface in which tetrafluoroethylene and a metal (nickel, chromium, titanium,
It is preferably used in an ink jet recording method using a recording head which has been subjected to a water repellent treatment such as eutectoid plating with gold, platinum, silver, iridium and the like. By combining the recording head having such a nozzle surface with the ink composition according to the present invention, it is possible to reduce the generation of deposits on the nozzle surface. Further, even if the deposits are formed, the deposits can be easily removed by a cleaning operation in which rubber or felt is brought into contact. According to a preferred aspect of the present invention, the contact angle between the nozzle surface subjected to the water repellent treatment and the ink composition is 50 ° C. to 50 ° C. at 50 ° C.
° or more. When the contact angle is in this range, good printing can be performed.

In the case of an ink using a pigment as a colorant and having a relatively large amount of solid matter, a nozzle that does not discharge for a long time tends to dry and thicken the ink on the front surface of the nozzle, causing a phenomenon that printing is disturbed. Therefore, by finely moving the ink so as not to be ejected on the front surface of the nozzle, the ink is agitated and the ink can be ejected stably. The fine movement method can be generated by controlling the pressure of the pressurizing means for discharging the ink so that the ink is not discharged. When performing such control, the use of an electrostrictive element as the pressurizing means
It is preferable because of its easy control. Further, by using this mechanism, the pigment concentration in the ink can be increased, so that the pigment ink has a high color density and can stably eject the ink.

When the fine movement is performed on the nozzle surface in the ink jet recording apparatus, it is effective for an ink composition having a pigment content of about 3% to 15% by weight, and more preferably 5% to 10% by weight. % Of the ink composition.

The ink composition according to the present invention may be filled with a polyurethane foam and filled in an ink tank having a structure in which the ink and the urethane foam are in contact with each other for use. In this case, a glycol ether or an acetylene glycol-based surfactant which is preferably used in the present invention is adsorbed on the urethane foam. Therefore, it is preferable to add excessively in consideration of the amount to be adsorbed. Further, the urethane foam can secure a negative pressure by using the ink composition according to the present invention, and can be clogged by being decomposed or generating foreign matter by each component of the ink used in the present invention. Less is. As the curing catalyst for this urethane foam, a catalyst containing a metal salt or a cationic system is not used, and polyfunctional isocyanates such as tolylene diisocyanate and meta-xylylene diisocyanate and glycols such as polypropylene glycol and polyethylene glycol having an average molecular weight of about 300 to 3000 are used. , Glycerin, pentaerythritol, dipentaerythritol, neopentyl glycol, propylene glycol, 1,3-butanediol, 1,4-
It is preferable to use a urethane foam made of a substance having a plurality of hydroxy groups such as butanediol and 1,5-pentanediol from the viewpoint of securing negative pressure due to the stability of the foam shape and the chemical stability.

[0057]

EXAMPLE Preparation of Polymer Fine Particles 200 g of ion-exchanged water was placed in a reaction vessel equipped with a dropping device, a thermometer, a water-cooled reflux condenser, and a stirrer.
The temperature was raised to 70 ° C. with stirring in a nitrogen atmosphere. 1 g of sodium alkylnaphthalenesulfonate was added to the reaction vessel as an emulsifier, and potassium persulfate was further added as a polymerization initiator. 100 g of benzyl methacrylate, 100 g of dodecyl acrylate, 2 g of 1,6-hexanediol dimethacrylate, and 5 g of methacrylic acid were added, and 200 g of ion-exchanged water was added, followed by emulsification. The emulsion was gradually dropped into a reaction vessel to cause a reaction.

After completion of the reaction, 65 g of diethylene glycol monobutyl ether was added to the reaction solution, and the mixture was left at 70 ° C. for 5 hours. Then return to room temperature and adjust the pH to 8 ~ with ammonia.
8.5. After that, the reaction solution is filtered with a filter,
A dispersion of polymer particles was obtained.

Preparation of Ink Compositions Examples 1 to 8 and Comparative Examples 1 to 3 having the following compositions were prepared .

In the following, the water-soluble pigments 1 to 4 have a particle size of 1
A pigment having a carbon black of 0 to 300 nm and a degree of dispersion of 10 or less, which is subjected to a dispersion treatment by oxidation or grafting to introduce a group such as a carbonyl group, a carboxyl group, a hydroxyl group, or a sulfone group. I do.
The average particle size (nm) was as shown in parentheses.

The polymer fine particles are prepared according to the above-mentioned preparation of the polymer fine particles, and are obtained by filtering with a filter so as to have an average diameter in parentheses.

In the following, the water-soluble dye 1 is C.I. I. Direct black 154. The water-soluble dye 2 is C.I. I. Direct Yellow 132.

The following abbreviations were used for the surfactants. TDD: 2,4,7,9-tetramethyl-5-decyne-
4,7-diol DOD: 3,6-dimethyl-4-octyne 3,6-diol TDDE10: ethylene oxide adduct of 2,4,7,9-tetramethyl-5-decyne-4,7-diol (ethylene oxide 10 Mol) TDDE6P2: 2,4,7,9-tetramethyl-5-
Adduct of ethylene oxide and propylene oxide of decyne-4,7-diol (ethylene oxide 5 mol, propylene oxide 2 mol) TDDP2: propylene oxide of 2,4,7,9-tetramethyl-5-decyne-4,7-diol DODE 10: 3,6-dimethyl-4-octyne 3,6
-Ethylene oxide adduct of diol (ethylene oxide 10 mol) TDDE6P2: 3,6-dimethyl-4-octyne 3,
Adduct of ethylene oxide and propylene oxide of 6-diol (ethylene oxide 5 mol, propylene oxide 2 mol) TDDP2: 3,6-dimethyl-4-octyne 3,6-
Adduct of diol with propylene oxide (propylene oxide 2 mol)

The following surfactants A to F mean the following. Surfactant A: Polyethylene glycol monoalkyl ether phosphate (alkyl group is a mixture having 8 to 30 carbon atoms) Surfactant B: Polyethylene glycol monooctyl ether monophosphate and diphosphate mixture Surfactant C: Diphosphate of polyethylene glycol nonyl phenyl ether Surfactant D: diborate of polyethylene glycol nonyl phenyl ether Surfactant E: polyethylene glycol octyl phenyl ether Surfactant F: polyethylene glycol nonyl phenyl ether

The following abbreviations were used for the organic solvents. PGmBE: propylene glycol monobutyl ether DPGmBE: dipropylene glycol monobutyl ether DEGmHE: diethylene glycol monohexyl ether TEGmPeE: triethylene glycol monopentyl ether TEGmHE: triethylene glycol monohexyl ether PGEGmBE: propylene glycol ethylene glycol monobutyl ether PGDEGMmBE: propylene glycol diethylene glycol monobutyl PGEGmPeE: Propylene glycol ethylene glycol monopentyl ether PGEGmPeE: Propylene glycol diethylene glycol monopentyl ether PGEGmHE: Propylene glycol ethylene glycol monohexyl ether PGDEG mHE: propylene glycol diethylene glycol monohexyl ether EGPGmBE: ethylene glycol propylene glycol monobutyl ether EGDPGmBE: ethylene glycol dipropylene glycol monobutyl ether EGPGmPeE: ethylene glycol propylene glycol monopentyl ether EGDPGmPeE: ethylene glycol dipropylene glycol monopentyl ether EGPGmHE: ethylene glycol propylene glycol Monohexyl ether EGDPGmHE: Ethylene glycol dipropylene glycol monohexyl ether DEGmBE: Diethylene glycol monobutyl ether TEGmBE: Triethylene glycol monobutyl ether DEGmME: Diethylene glyco Monomethyl ether

In the remaining water, 0.1 to 1% by weight of a preservative, Proxel XL-2 (Zeneca, UK), was used to prevent corrosion of the metal part of the head member due to contact with the ink. 0.001 to 0.05% by weight of triazole, and 0.01 to 0.3% of ethylenediaminetetraacetic acid (EDTA) in order to remove adverse effects due to precipitation of metal salts in the ink.
% By weight.

Example 1 Amount Added Water-soluble pigment 1 (105) 5.0% by weight PGmBE 1.0% by weight PGEGmBE 3.0% by weight DEGmHE 3.0% by weight DEGmBE 8.0% by weight TDD 1.0% by weight Surfactant A 1.0% by weight Polymer fine particles (50) 10.0% by weight Glycerin 8.0% by weight 1,5-pentanediol 3.0% by weight Triethanolamine 0.8% by weight Potassium hydroxide 0.0% 1% by weight Deionized water

Example 2 Water-soluble pigment 2 (85) 4.5% by weight DPGmBE 2.0% by weight PGEGmHE 1.0% by weight EGPGmBE 1.0% by weight TEGmBE 7.0% by weight TDD 0.5% by weight DOD 0 0.5% by weight Surfactant B 1.2% by weight Polymer fine particles (80) 3.0% by weight Dipropylene glycol 5.0% by weight Reduced starch sugar 3.5% by weight Monoethanolamine 0.9% by weight hydroxylation 0.1% by weight of lithium ion exchanged water

Example 3 5.5% by weight of water-soluble pigment 3 (90) 1.0% by weight of EGDPGmHE 1.0% by weight of PGDGmPeE 8.0% by weight of TEGmBE 2.0% by weight of DOD 1.0% by weight of surfactant C % Polymer fine particles (150) 4.0% by weight Diethylene glycol 7.0% by weight Thiodiglycol 3.5% by weight Maltitol 2.0% by weight 1,6-hexanediol 5.0% by weight Diethanolamine 0.2% by weight Triethanolamine 0.4% by weight Potassium hydroxide 0.1% by weight Deionized water

Example 4 Water-soluble pigment 4 (80) 5.0% by weight EGPGmHE 2.0% by weight TEGmHE 4.0% by weight DEGmBE 8.0% by weight TDDE10 1.0% by weight Surfactant C 1.0% by weight % Surfactant E 1.0% by weight Polymer fine particles (10) 5.0% by weight Ethylene glycol 3.0% by weight Triethylene glycol 3.0% by weight 1,5-pentanediol 2.0% by weight glycerin 6. 2 wt% sodium benzoate 0.1 wt% tripropanolamine 0.3 wt% dipropanolamine 0.1 wt% sodium hydroxide 0.1 wt% ion exchange water

Example 5 Water-soluble pigment 1 (105) 3.0% by weight Water-soluble dye 1 1.0% by weight EGDPGmPeE 2.0% by weight EGPGmPeE 1.0% by weight EGDPGmBE 2.0% by weight DEGmBE 10.0% by weight % DODE10 0.5% by weight Surfactant B 0.5% by weight Surfactant F 0.5% by weight Polymer fine particles (90) 3.0% by weight PEG400 4.0% by weight Propylene glycol 6.0% by weight Mono Propanolamine 0.9 wt% Monomethylethanolamine 0.1 wt% Ammonia 0.3 wt% Potassium hydroxide 0.1 wt% Deionized water

Example 6 Water-soluble pigment 2 (85) 4.0% by weight Water-soluble dye 2 1.0% by weight TEGmPeE 2.0% by weight PGEGmPeE 2.5% by weight EGDPGmPE 1.5% by weight TEGmBE 6.0% by weight % DEGmBE 4.0% by weight TDDE6P2 0.8% by weight Surfactant A 0.8% by weight Surfactant F 0.5% by weight Polymer fine particles (110) 3.0% by weight Propanediol 5.0% by weight Propylene Glycol 3.0% by weight Thiodiglycol 2.0% by weight 1,5-pentanediol 5.0% by weight Dimethylethanolamine 0.5% by weight 0.1% by weight of sodium hydroxide 0.1% by weight of rubidium hydroxide Ion Exchange water level

Example 7 Water-soluble pigment 3 (90) 5.0% by weight PGDEmmBE 2.0% by weight PGDEmHE 3.0% by weight DEGmBE 8.0% by weight TDDP2 0.5% by weight DOD 0.5% by weight Surface activity Agent A 0.7% by weight Surfactant F 0.3% by weight Polymer fine particles (40) 5.0% by weight 1,4-butanediol 5.0% by weight Tetrapropylene glycol 3.0% by weight Tetraethylene glycol 2 0.5 wt% Trimethylolpropane 5.0 wt% Dimethylethanolamine 1.0 wt% Tetramethylammonium 0.5 wt% Sodium hydroxide 0.1 wt% Cesium hydroxide 0.1 wt% Triethanolamine 0.5 Wt% ion exchange water

Example 8 Water-soluble pigment 4 (80) 5.5% by weight PGDEmmBE 6.0% by weight DEGmBE 9.0% by weight TDDE6P2 0.6% by weight TDDP2 0.4% by weight Surfactant D 0.5% by weight % Surfactant E 0.3% by weight Surfactant F 0.3% by weight Polymer fine particles (75) 7.0% by weight Glycerin 5.0% by weight Diethylene glycol 5.0% by weight Tripropylene glycol 5.0% by weight Triethanolamine 0.9% by weight Potassium hydroxide 0.1% by weight Deionized water

Pigments 5 to 7 used in the following comparative examples are carbon blacks dispersed using a random copolymerization type styrene acrylic acid-based dispersant. Comparative Example 1 Pigment 5 (90) 5.0% by weight Glycerin 10.0% by weight Dispersant 3.0% by weight Nonionic surfactant 1.0% by weight Deionized water balance

Comparative Example 2 Pigment 6 (85) 5.5% by weight DEGmME 7.0% by weight Diethylene glycol 10.0% by weight 5.0% by weight 2-pyrrolidone Deionized water

Comparative Example 3 Pigment 7 (110) 5.5% by weight Water-soluble dye (Food Black 2) 2.5% by weight Diethylene glycol 10.0% by weight Nonionic surfactant 1.0% by weight Deionized water balance amount

Evaluation Test of Ink Composition The above-mentioned ink composition was filled in an ink jet printer MJ-930C manufactured by Seiko Epson Corporation, and an image was formed on a recording medium. The recording medium used was Conq
useror paper, Favorite paper, Modo Copy
Paper, RapidCopy paper, EPSON EPP paper, X
erox P paper, Xerox 4024 paper, Xerox
10 papers, Neenha Bond papers, Riccopy 6
200 paper, Yamayuri paper and Xerox R paper. The printing quality, finger touch, and water resistance of the obtained image were evaluated as follows.

Print quality The bleeding of the dried printed matter was judged according to the following evaluation criteria. Evaluation A: Almost no bleeding. Evaluation B: Although bleeding is slightly observed, it is within a practically acceptable range. Evaluation C: Bleeding is observed to deteriorate the image. Evaluation D: The image is extremely poor due to bleeding.

Rubbing Resistance The dried printed matter was rubbed with a yellow aqueous fluorescent pen (ZEBRA PEN2, manufactured by Zebra Co.) to check the stain condition of the printed matter. The results were determined according to the following evaluation criteria. Evaluation A: The color does not fade even when rubbed a plurality of times. Evaluation B: Color does not fade even after rubbing once. Evaluation C: The color is slightly removed by rubbing once. Evaluation D: The color falls when rubbed once.

Pure water was dripped on the printed matter having been subjected to the water-resistant drying, and traces of water droplets on the printed matter after one minute were examined. The results were determined according to the following evaluation criteria. Evaluation A: No trace remains. Evaluation B: Almost no trace remains. Evaluation C: A trace remains. Evaluation D: Significant marks remain.

The above results were as described in the following table.

[Table 1]

Claims (19)

[Claims] 1. A colorant, one or more organic solvents,
A method for producing an ink composition for ink jet recording comprising at least polymer particles and water, wherein the polymer particles are brought into contact with at least one kind of the organic solvent to swell, and the swelling is in an equilibrium state. In the state reached, prepared polymer fine particles whose diameter is placed in the range of 10 to 200 nm, the polymer fine particles, the colorant, the organic solvent,
Mixing the water with the water to form an ink composition. 2. The method according to claim 1, wherein the colorant is a pigment, and at least one of the organic solvents is a glycol ether.
The method described in. 3. The method according to claim 1, wherein the polymer fine particles are swollen by glycol ether. 4. The method according to claim 3, wherein the amount of the glycol ether added to the ink composition is 5 to 20% by weight. 5. The method of claim 1, wherein the glycol ether is (di or tri) ethylene glycol monobutyl ether, (mono or di) propylene glycol monobutyl ether,
(Di or tri) ethylene glycol mono (pentyl or hexyl) ether, propylene glycol (mono or di) ethylene glycol mono (butyl, pentyl, or hexyl) ether, and ethylene glycol (mono or di) propylene glycol mono (butyl, pentyl) Or hexyl) ether, at least one selected from the group consisting of: 6. The method according to claim 1, wherein the ink composition comprises a surfactant. 7. The method according to claim 1, wherein the surfactant is 2,4,7,9-tetramethyl-5-decyne-4,7-diol, 3,6-dimethyl-4-octyne-3,6-diol, 4,
Ethylene oxide and / or propylene oxide adducts of 7,9-tetramethyl-5-decyne-4,7-diol and 3,6-dimethyl-4-octyne-3,
The method according to claim 6, which is at least one selected from the group consisting of ethylene oxide and / or propylene oxide adducts of 6-diol. 8. The method according to claim 6, wherein the amount of the surfactant added is 3% by weight or less. 9. The ink composition further comprising at least one surfactant selected from the group consisting of an anionic surfactant, a nonionic surfactant, and an amphoteric surfactant having an HLB of 8 or more. 7. The method of claim 6, wherein the method comprises: 10. The method according to claim 1, further comprising an organic amine and an inorganic alkali as an alkalizing agent. 11. The group of organic amines comprising (mono, di, or tri) ethanolamine, (mono, di, or tri) propanolamine, (mono or di) methylethanolamine, ammonia, and tetramethylammonium. The method according to claim 10, wherein the inorganic alkali is at least one selected from the group consisting of lithium hydroxide, sodium hydroxide, and potassium hydroxide. 12. The method of claim 1, wherein the glycol ether is (mono or di) propylene glycol monobutyl ether, (di or tri) ethylene glycol mono (pentyl or hexyl) ether, propylene glycol (mono or di) ethylene glycol mono (butyl, pentyl or Hexyl) ether, and at least one selected from the group consisting of ethylene glycol (mono or di) propylene glycol mono (butyl, pentyl, or hexyl) ether, further containing (di or tri) ethylene glycol monobutyl ether The method of claim 1, comprising: 13. The method according to claim 13, wherein the organic solvent is glycerin, (mono,
Di, tri, tetra, or poly) ethylene glycol,
(Mono, di, tri, or tetra) propylene glycol, (propane, butane, pentane, or hexane)
2. The method according to claim 1, wherein the method is at least one selected from the group consisting of diols and thiodiglycols. 14. The method according to claim 1, wherein the ink composition has a surface tension at 5 to 45 ° C. of 20 to 40 mN / m. 15. An ink composition produced by the method according to claim 1 and used in an ink jet recording method. 16. An ink composition produced by the method according to claim 1, which is used in an ink jet recording apparatus using an ink jet head having a mechanism based on a response of an electrostrictive element. 17. A method for producing polymer fine particles which is used by being added to an ink composition for inkjet recording, comprising one or more organic solvents, the method comprising preparing polymer fine particles, Is contacted with at least one of the above-mentioned organic solvents to swell, and in a state where the swelling reaches an equilibrium state, a polymer fine particle having a diameter in the range of 10 to 200 nm is obtained. 18. The method according to claim 17, wherein said organic solvent is a glycol ether. (19) A polymer fine particle obtained by the method according to (18).