JP2009270043A - Nonaqueous inkjet-printing ink and method for inkjet-recording - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a nonaqueous inkjet-printing ink which includes an printing aptitude (scratch resistance, alcohol wipability resistance) for recording media made of plastics such as polyvinyl chloride or the like, is excellent in safety, is free from the problem of odor, causes no unusual state in an inkjet head even in a long-period use, is usable stably and is small in ejectability change depending on a storage environment over a long-period when the ink is used after a long-period storage, and to provide a method for inkjet-recording using it. <P>SOLUTION: The nonaqueous inkjet-printing ink includes at least a pigment and a fixing resin, and also a compound (A) comprising one or more kinds of compounds selected from a specific sulfoxide compound group and sulfone compound group, and a solvent comprising one or more kinds of compounds selected from a specific oxyethylene diester compound group and oxypropylene diester compound group, and has a content of the compound (A) of from 1.5 mass% or more and 30 mass% or less, and a content of moisture of from 0.5% or more and 4% or less. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a novel non-aqueous inkjet ink and inkjet recording method.

  In recent years, inkjet recording methods are simple and can produce images at low cost, and thus have been applied to various printing fields such as photographs, various printing, marking, and special printing such as color filters.

  As the ink-jet ink used in such printing applications, water-based inks mainly containing water, non-volatile solvents that do not volatilize at room temperature, oil-based inks that do not substantially contain water, and solvents that volatilize at room temperature are used. Mainly, non-aqueous ink substantially free of water, hot melt ink that heats and melts solid ink at room temperature, actinic ray curable ink that cures with actinic rays such as light after printing, etc. There are inkjet inks, and they are used properly according to the application.

  On the other hand, plastic recording media such as polyvinyl chloride and polyethylene are used as recording media for outdoor postings that require long-term weather resistance and printed materials that require adhesion to curved objects. Recording media made of soft polyvinyl chloride are used in a wide range of applications. There are many methods for printing on soft polyvinyl chloride, but there is an inkjet recording method as a method suitable for the production of a small variety of products because there is no need to prepare a plate and the time to finish is short.

  When ink jet recording is performed on soft polyvinyl chloride, as an ink jet ink to be used, a non-aqueous ink containing a large amount of cyclohexanone or the like has been conventionally used. For example, an ink jet ink containing cyclohexanone is disclosed ( For example, see Patent Document 1). This cyclohexanone has a high solubility in soft polyvinyl chloride, and since the pigment in the ink-jet ink enters into the soft polyvinyl chloride, good scratch resistance and glossiness can be obtained. However, cyclohexanone has been designated as a first type organic solvent, which is not only a problem in safety, but also has a drawback that a local exhaust device is required when handling inkjet ink containing cyclohexanone.

  On the other hand, non-aqueous inks characterized by not containing cyclohexanone have been developed and sold. For example, a non-aqueous ink containing a solvent such as N-methylpyrrolidone or amide has been disclosed as a solvent for dissolving polyvinyl chloride in place of cyclohexanone having the above-mentioned problems (for example, Patent Documents). 2 and 3).

  Further, for the purpose of improving image fastness such as scratch resistance, a non-aqueous ink to which a fixing resin such as vinyl chloride-vinyl acetate copolymer or acrylic is added is disclosed (for example, see Patent Documents 4 and 5). . With these configurations, it was possible to obtain an inkjet ink capable of suppressing odor to some extent and forming an image having scratch resistance against polyvinyl chloride. However, when these inkjet inks are used over a long period of time, an inkjet head It has been found that there is a new problem that normal image formation cannot be performed gradually.

Therefore, the present situation is that a non-aqueous inkjet ink that has no safety and odor problems, has sufficient suitability when printed on polyvinyl chloride, and can be used stably over a long period of time has not yet been obtained. .
Japanese translation of PCT publication No. 2002-526631 JP 2005-15672 A Japanese Patent Laid-Open No. 2005-60716 JP 2005-36199 A International Publication No. 04/7626 Pamphlet

  The present invention has been made in view of the above problems, and has an object of having printability (rubbing resistance, alcohol wiping resistance) on a plastic recording medium such as polyvinyl chloride, excellent safety, and odor. The ink jet head does not cause abnormalities even when used for a long time, can be used stably, and when using ink after long-term storage, there is little change in ejection properties due to long-term storage environment. An object of the present invention is to provide a water-based inkjet ink and an inkjet recording method using the same.

  The above object of the present invention is achieved by the following configurations.

  1. A compound (A) comprising at least a pigment, a fixing resin, one or more compounds selected from the group of compounds represented by the following general formulas (1) and (2), and a compound represented by the following general formula (3) A solvent (B) comprising one or more compounds selected from the group, the content of the compound (A) is 1.5% by mass or more and 30% by mass or less, and the water content is 0.5%. The non-aqueous inkjet ink characterized by being 4% or less.

^(Wherein, R 1, ^{R 2} are each carbon atoms represent a 1-6 substituents may be bonded by ^{R 1} and ^{R 2} form a ring.)

(In the formula, R ³ and R ⁴ each represent a substituent having 1 to 6 carbon atoms, and R ³ and R ⁴ may be bonded to form a ring.)

(In the formula, R ⁷ and R ⁸ each represent a methyl group or an ethyl group, and OX ² represents an oxyethylene group or an oxypropylene group.)
2. 2. The non-aqueous inkjet ink according to 1 above, wherein the content of the solvent (B) is 1% by mass or more and 30% by mass or less.

  3. 3. The non-aqueous inkjet ink according to 1 or 2, wherein the solvent (B) is at least one selected from ethylene glycol diacetate and propylene glycol diacetate.

  4). The non-aqueous inkjet according to any one of 1 to 3, further comprising a solvent (C) comprising one or more compounds selected from the group of compounds represented by the following general formula (4): ink.

(In the formula, R ⁵ and R ⁶ each represent a methyl group or an ethyl group, and OX ¹ represents an oxyethylene group or an oxypropylene group.)
5. 5. The non-aqueous inkjet ink as described in 4 above, wherein the content of the solvent (C) is 50% by mass or more and 90% by mass or less.

  6). 6. The non-aqueous inkjet ink according to 4 or 5, wherein the solvent (C) is at least one selected from diethylene glycol diethyl ether, dipropylene glycol dimethyl ether, and dipropylene glycol diethyl ether.

  7. 7. The non-aqueous inkjet ink according to any one of 1 to 6, wherein the fixing resin is a resin synthesized by a solution polymerization method.

  8). Vinyl chloride-vinyl acetate copolymer, vinyl chloride-vinyl acetate-maleic anhydride copolymer, vinyl chloride-vinyl acetate-vinyl alcohol copolymer, and chloride, wherein the fixing resin has a number average molecular weight in the range of 10,000 to 30,000. The non-aqueous inkjet ink according to any one of 1 to 7 above, which is at least one selected from vinyl-vinyl acetate-hydroxyalkyl acrylate copolymers.

  9. 9. An ink jet recording method comprising recording on polyvinyl chloride as a recording medium using the non-aqueous ink jet ink according to any one of 1 to 8 above.

  According to the present invention, it has printability (rubbing resistance, alcohol wiping resistance) on a plastic recording medium such as polyvinyl chloride, is excellent in safety, has no odor problem, and can be used for a long period of use. Providing a non-aqueous inkjet ink that can be used stably without causing abnormalities, and has a small change in ejectability due to a long-term storage environment when using ink after long-term storage, and an inkjet recording method using the same We were able to.

  Hereinafter, the best mode for carrying out the present invention will be described in detail.

  As a result of various studies on non-aqueous ink-jet inks (also simply referred to as ink-jet inks), the present inventor has found that polyvinyl chloride is used in conventionally known non-aqueous ink-jet inks containing solvents such as N-methylpyrrolidone and amide. In contrast, the present inventors have found that, although good printability is exhibited, when these ink-jet inks are used for a long period of time, abnormal ejection of the ink-jet head is caused and normal image formation cannot be gradually performed.

  Abnormalities in inkjet heads in long-term use are thought to occur when solvents such as N-methylpyrrolidone and amide swell and dissolve components and adhesives of inkjet heads, and the content of these solvents in inkjet inks However, in this case, the printability for plastic recording media such as polyvinyl chloride becomes insufficient, and the printability for plastic recording media such as polyvinyl chloride and the long-term durability of inkjet heads. At present, an ink-jet ink having both properties has not yet been obtained.

  On the other hand, the present inventors have studied various solvents and combinations thereof in view of the above problems, and as a result, the sulfoxide represented by the general formulas (1) and (2) or the sulfone compound group 1 is selected. Printability (fast-drying property) for plastic recording media such as polyvinyl chloride using non-aqueous ink jet ink containing 1.5% by mass or more and 30% by mass or less of compound (A) and pigment and fixing resin We have found that it is possible to realize a non-aqueous ink jet ink that has both excellent anti-emission stability and safety and no problem of odor.

  As a result of further investigation, when the non-aqueous inkjet ink is stored for a long period of time at high and low temperatures, the ink is returned to room temperature and ejected using an inkjet head. Problems, such as floating without ink landing on the paper and becoming ink mist, smearing the inside of the printer, or landing on the paper to degrade the image quality, and continuous ejection will cause defective discharge. New issues such as these occurred.

  As a result of intensive studies by the present inventors on the problem that the ejection properties change according to the long-term storage temperature of the ink, the ejection properties change depending on the storage temperature for a long period of time. The solubility of the fixing resin depends on the storage temperature. It is thought that it is caused by the change, the moisture content is 0.5% or more and 4% or less, and it contains the solvent (B) composed of one or more kinds of compounds represented by the general formula (3). It was excellent in injection stability regardless of the situation and led to solving the problem.

In the general formula (1), R ¹ and R ² each represent a substituent having 1 to 6 carbon atoms, for example, a linear or branched alkyl such as a methyl group, an ethyl group, an n-propyl group, or an isopropyl group. Groups, alkyl groups substituted with heteroatoms such as hydroxyethyl group, acetyl group, and acetonyl group, cyclic groups such as cyclohexyl group and phenyl group, or aromatic substituents, and R ¹ and R ² are They may be the same or different, and R ¹ and R ² may be bonded to each other to form a ring.

In the general formula (2), R ³ and R ⁴ each represent a substituent having 1 to 6 carbon atoms, for example, a linear or branched alkyl such as a methyl group, an ethyl group, an n-propyl group, or an isopropyl group. Groups, alkyl groups substituted by heteroatoms such as hydroxyethyl group, acetyl group and acetonyl group, cyclic groups such as cyclohexyl group and phenyl group, or aromatic substituents, and further R ³ and R ⁴ are They may be the same or different, and R ³ and R ⁴ may be bonded to each other to form a ring.

  Examples of the compound represented by the general formulas (1) and (2) include dimethyl sulfoxide, diethyl sulfoxide, methyl ethyl sulfoxide, diphenyl sulfoxide, tetraethylene sulfoxide, dimethyl sulfone, methyl ethyl sulfone, and methyl-isopropyl sulfone. , Methyl-hydroxyethyl sulfone, sulfolane and the like.

  The content of the compound (A) in the inkjet ink is characterized by containing 1.5% by mass or more and 30% by mass or less, preferably 3% by mass or more and 20% by mass or less, more preferably It is 5 mass% or more and 15 mass% or less. When the content of the compound (A) is 1.5% by mass or more, the ink has sufficient solubility in polyvinyl chloride, and scratch resistance and alcohol wiping resistance against polyvinyl chloride can be obtained. Moreover, if it is 3 mass% or more, the abrasion resistance with respect to polyvinyl chloride and alcohol wiping resistance are favorable, and if it is 30 mass% or less, stable emission without causing abnormalities of the inkjet head due to long-term use. It can be performed.

  The inkjet ink of the present invention may contain a non-aqueous solvent, but may contain a solvent (B) composed of one or more compounds selected from the compound group represented by the general formula (3). It is a feature.

In the general formula (3), R ⁷ and R ⁸ each represent a methyl group or an ethyl group, and OX ² represents an oxyethylene group or an oxypropylene group. Specific examples of the compound represented by the general formula (3) according to the present invention include ethylene glycol diacetate and propylene glycol diacetate.

  The content of the solvent (B) in the inkjet ink is preferably 1% by mass or more and 30% by mass or less, more preferably 5% by mass or more and 20% by mass or less. If the content of the solvent (B) is 1% by mass or more, the continuous ejection property when the head is filled with the ink returned to room temperature after being stored at a high temperature for a long time and ejected becomes stable. For example, the continuous ejection property when the ink is returned to the room temperature after being stored at a low temperature for a long time and then ejected is stabilized. If it is 30% by mass or less, stable ejection properties can be obtained even if the head is filled with ink for a long time.

  The inkjet ink of the present invention can contain a non-aqueous solvent, but contains a solvent (C) composed of one or more compounds selected from the compound group represented by the general formula (4). It is preferable.

In the general formula (4), R ⁵ and R ⁶ each represent a methyl group or an ethyl group, and OX ¹ represents an oxyethylene group or an oxypropylene group. Specific examples of the compound represented by the general formula (4) according to the present invention include diethylene glycol dimethyl ether, diethylene glycol diethyl ether, dipropylene glycol dimethyl ether, and dipropylene glycol diethyl ether.

  Among these, the component of the solvent (C) is preferably at least one selected from diethylene glycol diethyl ether, dipropylene glycol dimethyl ether, and dipropylene glycol diethyl ether, and the odor of the ink when printed on polyvinyl chloride Will be less.

  The content of the solvent (C) in the inkjet ink is preferably 50% by mass or more and 90% by mass or less, and such a solvent configuration can improve the drying property of the ink. In addition, intermittent ejection properties are improved.

  In addition to the compound (A), the solvent (B) and the solvent (C) according to the present invention, the inkjet ink of the present invention may contain a conventionally known solvent as long as the object and effects of the present invention are not impaired. Examples of such solvents include alkylene glycol monoalkyl ethers such as diethylene glycol monoethyl ether, triethylene glycol monomethyl ether, dipropylene glycol monomethyl ether, and tripropylene glycol monomethyl ether, ethylene glycol dibutyl ether, and tetraethylene glycol dimethyl ether. And alkylene glycol dialkyl ethers such as ethylene glycol monobutyl ether acetate.

  The non-aqueous inkjet ink of the present invention is characterized by a water content of 0.5% or more and 4% or less. If the water content is 0.5% or more, it can be adjusted by a physical dehydration process such as a heating process, a dehydration process, and a decompression process in the final stage of ink production. If the water content is 4% or less, Even in inks stored at low or high temperatures, there is no change in satellite generation before and after storage, and good ejection properties can be obtained.

  Next, the fixing resin according to the present invention will be described.

  In the ink-jet ink of the present invention, various fixing resins (hereinafter also simply referred to as resins) are added in order to improve fixability when recording on a plastic recording medium such as polyvinyl chloride.

  Examples of the resin to be added include acrylic resins, polyester resins, polyurethane resins, vinyl chloride resins, vinyl chloride-vinyl acetate copolymer resins, and the like.

  Specifically, acrylic resins such as Jonkrill (Johnson Polymer), ESREC P (Sekisui Chemical), polyester resins such as Elite (Unitika), Byron (Toyobo), Byron UR (Toyobo), NT-Hilamic (manufactured by Dainichi Seika), Crisbon (manufactured by Dainippon Ink and Chemicals), Nippon resin (manufactured by Nippon Polyurethane) Examples thereof include vinyl chloride resins such as latex (manufactured by Asahi Kasei Chemicals), Sumilite (manufactured by Sumitomo Chemical), Sekisui PVC (manufactured by Sekisui Chemical), and UCAR (manufactured by Dow Chemical).

  The fixing resin acts as a binder that adheres a coloring material such as a pigment to the recording medium after printing. The larger the molecular weight of the fixing resin, the better the adhesion and durability. In addition, the smaller the molecular weight, the lower the viscosity of the ink. However, the lower the viscosity, the lower the energy required for ejecting the ink during printing, so that the inkjet head is not burdened and it is easier to eject stably. Accordingly, if the number average molecular weight is 10,000 or more, the fixing property after printing is sufficiently exhibited, and if it is 30000 or less, it does not impose a load on the emission of the ink, which is preferable.

  Particularly preferred fixing resins have a number average molecular weight in the range of 10,000 to 30,000, and compositions include vinyl chloride-vinyl acetate copolymer, vinyl chloride-vinyl acetate-maleic anhydride copolymer, vinyl chloride-vinyl acetate- At least one resin selected from vinyl alcohol copolymer and vinyl chloride-vinyl acetate-hydroxyalkyl acrylate copolymer, vinyl chloride-vinyl acetate copolymer and vinyl chloride-vinyl acetate-maleic anhydride copolymer These vinyl chloride-vinyl acetate copolymers and vinyl chloride-vinyl acetate-maleic anhydride copolymers may be mixed with acrylic resins, polyester resins, polyurethane resins, etc. May be used.

  By adding these fixing resins to the ink-jet ink of the present invention, it is possible to improve the emission stability, abrasion resistance and alcohol wiping resistance in a balanced manner.

  The alcohol wiping resistance referred to in the present invention is resistance to disturbance such as image peeling when wiping the surface of the image with ethanol or a mixed solvent of ethanol and water. Wipe off the image surface with alcohol on a poster for outdoor use. User needs.

  As a method for synthesizing the fixing resin according to the present invention, a suspension polymerization method, an emulsion polymerization method, a solution polymerization method, and the like can be applied without particular limitation. Among them, the solution polymerization method is preferable.

  The solution polymerization method is one of the methods used for radical polymerization of a monomer having a vinyl group. The monomer and initiator are dissolved in a solvent in which the polymer to be generated is soluble, and the polymerization is performed by heating. Is the method. The fixing resin synthesized by the solution polymerization method has a high solubility even if it has a relatively high molecular weight, and the change in ejection properties before and after long-term storage of the ink is small, which is even better.

  The content of the fixing resin in the inkjet ink of the present invention is preferably 1 to 10% by mass. When the content is 1% by mass or more, the image weather resistance when recorded on polyvinyl chloride is enhanced, and when the content is 10% by mass or less, the ink ejection from the inkjet head is easily stabilized, and the more preferable content The range of the amount is in the range of 3 to 7% by mass.

  Next, the pigment according to the present invention will be described.

  In the non-aqueous ink jet ink of the present invention, the weather resistance of the recorded matter recorded on a plastic recording medium such as polyvinyl chloride can be enhanced by using a pigment as a coloring material.

  As the pigment that can be used in the present invention, conventionally known pigments can be used without particular limitation. For example, insoluble pigments, organic pigments such as lake pigments, and inorganic pigments such as carbon black can be preferably used.

  The insoluble pigment is not particularly limited. , Thiazole, phthalocyanine, diketopyrrolopyrrole and the like are preferable.

  Specific pigments that can be preferably used include the following pigments.

  Examples of the magenta or red pigment include C.I. I. Pigment red 2, C.I. I. Pigment red 3, C.I. I. Pigment red 5, C.I. I. Pigment red 6, C.I. I. Pigment red 7, C.I. I. Pigment red 12, C.I. I. Pigment red 15, C.I. I. Pigment red 16, C.I. I. Pigment red 48 (Ca), C.I. I. Pigment red 48 (Mn), C.I. I. Pigment red 48: 1, C.I. I. Pigment red 53: 1, C.I. I. Pigment red 57 (Ca), C.I. I. Pigment red 57: 1, C.I. I. Pigment red 112, C.I. I. Pigment red 122, C.I. I. Pigment red 123, C.I. I. Pigment red 139, C.I. I. Pigment red 144, C.I. I. Pigment red 149, C.I. I. Pigment red 166, C.I. I. Pigment red 168, C.I. I. Pigment red 177, C.I. I. Pigment red 178, C.I. I. Pigment red 184, C.I. I. Pigment red 202, C.I. I. Pigment red 209, C.I. I. Pigment red 222, C.I. I. Pigment red 254, C.I. I. Pigment violet 19 and the like.

  Examples of the pigment for orange or yellow include C.I. I. Pigment orange 31, C.I. I. Pigment orange 43, C.I. I. Pigment yellow 1, C.I. I. Pigment yellow 2, C.I. I. Pigment yellow 3, C.I. I. Pigment yellow 12, C.I. I. Pigment yellow 13, C.I. I. Pigment yellow 14, C.I. I. Pigment yellow 15, C.I. I. Pigment yellow 15: 3, C.I. I. Pigment yellow 16, C.I. I. Pigment yellow 17, C.I. I. Pigment yellow 73, C.I. I. Pigment yellow 74, C.I. I. Pigment yellow 75, C.I. I. Pigment yellow 83, C.I. I. Pigment yellow 93, C.I. I. Pigment yellow 95, C.I. I. Pigment yellow 97, C.I. I. Pigment yellow 98, C.I. I. Pigment yellow 109, C.I. I. Pigment yellow 110, C.I. I. Pigment yellow 114, C.I. I. Pigment yellow 120, C.I. I. Pigment yellow 128, C.I. I. Pigment yellow 129, C.I. I. Pigment yellow 130, C.I. I. Pigment yellow 138, C.I. I. Pigment yellow 147, C.I. I. Pigment yellow 150, C.I. I. Pigment yellow 151, C.I. I. Pigment yellow 154, C.I. I. Pigment yellow 155, C.I. I. Pigment yellow 180, C.I. I. Pigment yellow 185, C.I. I. Pigment yellow 213, C.I. I. And CI Pigment Yellow 214.

  Examples of the pigment for green or cyan include C.I. I. Pigment blue 1, C.I. I. Pigment blue 2, C.I. I. Pigment blue 3, C.I. I. Pigment blue 15, C.I. I. Pigment blue 15: 2, C.I. I. Pigment blue 15: 3, C.I. I. Pigment blue 15: 4, C.I. I. Pigment blue 16, C.I. I. Pigment blue 22, C.I. I. Pigment blue 60, C.I. I. And CI Pigment Green 7.

In addition to the above, when red, green, blue and intermediate colors are required, the following pigments are preferably used alone or in combination. I. Pigment Red 209, 224, 177, 194;
C. I. Pigment Orange 43;
C. I. Vat Violet 3;
C. I. Pigment Violet 19, 23, 37;
C. I. Pigment Green 36, 7;
C. I. Pigment Blue 15: 6;
Etc. are used.

  Examples of black pigments include C.I. I. Pigment black 1, C.I. I. Pigment black 6, C.I. I. Pigment black 7 and the like.

  The content of these pigments in the inkjet ink of the present invention is preferably 2 to 10% by mass. In order to reduce the graininess of the image, a light color ink may be used. In this case, the pigment content is preferably 1/5 to 1/2 with respect to the dark color ink.

  The pigment according to the present invention is preferably used after being dispersed by a disperser together with a dispersant and other necessary additives according to other desired purposes. As the disperser, conventionally known dispersers such as a ball mill, a sand mill, an attritor, a roll mill, an agitator, a Henschel mixer, a colloid mill, an ultrasonic homogenizer, a pearl mill, a wet jet mill, and a paint shaker can be used.

  The average particle size of the pigment dispersion used in the inkjet ink of the present invention is preferably 10 nm or more and 200 nm or less, and more preferably 50 nm or more and 150 nm or less. By setting the average particle size to 10 nm or more, aggregation of pigment particles becomes difficult to occur, and by setting the average particle size to 200 nm or less, it becomes easy to suppress the phenomenon that the pigment settles when stored for a long period of time. Therefore, by setting the average particle size within the above range, it becomes easy to obtain an ink having good storage stability.

  The particle size of the pigment dispersion can be measured by a commercially available particle size measuring device using a light scattering method, an electrophoresis method, a laser Doppler method or the like. It is also possible to obtain a particle image with a transmission electron microscope on at least 100 particles and perform statistical processing on the image using image analysis software such as Image-Pro (manufactured by Media Cybernetics). Is possible.

  As the pigment dispersant, a surfactant, a polymer dispersant and the like are used, and a polymer dispersant is preferable. Polymer dispersing agents include (meth) acrylic resins, styrene- (meth) acrylic resins, hydroxyl group-containing carboxylic acid esters, salts of long-chain polyaminoamides and high molecular weight acid esters, salts of high molecular weight polycarboxylic acids, long Salt of chain polyaminoamide and polar acid ester, high molecular weight unsaturated acid ester, modified polyurethane, modified polyacrylate, polyether ester type anionic activator, naphthalenesulfonic acid formalin condensate salt, aromatic sulfonic acid formalin condensate salt, Examples thereof include polyoxyethylene alkyl phosphate ester, polyoxyethylene nonyl phenyl ether, stearylamine acetate, and pigment derivatives.

  Specifically, Jonkrill (manufactured by Johnson Polymer), Anti-Terra-U (manufactured by BYK Chemie), Disperbyk (manufactured by BYK Chemie), Efka (manufactured by Efka CHEMICALS), Floren (manufactured by Kyoeisha Chemical Co., Ltd.), Disparon (manufactured by Enomoto Kasei) ), Azisper (manufactured by Ajinomoto Fine-Techno), Demor (manufactured by Kao), Homogenol, Emulgen (manufactured by Kao), Solspurs (manufactured by Avicia), Nikkor (manufactured by Nikko Chemical) and the like.

  The content of the dispersant in the inkjet ink of the present invention is preferably 10 to 200% by mass with respect to the pigment. By setting the content to 10% by mass or more, the pigment dispersion stability is enhanced, and by setting the content to 200% by mass or less, the ink ejection from the inkjet head is easily stabilized.

  In addition to the above description, the inkjet ink of the present invention is publicly known depending on the purpose of improving the emission stability, print head and ink cartridge compatibility, storage stability, image storage stability, and other various performances as necessary. Various additives such as a viscosity modifier, a specific resistance modifier, a film forming agent, an ultraviolet absorber, an antioxidant, a discoloration inhibitor, an antifungal agent, and a rust inhibitor can be appropriately selected and used.

  The ink-jet head used when forming an image by discharging the ink-jet ink of the present invention may be an on-demand system or a continuous system. In addition, as a discharge method, an electro-mechanical conversion method (for example, a single cavity type, a double cavity type, a bender type, a piston type, a shear mode type, a shared wall type, etc.), an electro-thermal conversion method (for example, a thermal type) Any discharge method such as an ink jet type or a bubble jet (registered trademark) type may be used.

  In the ink jet recording method using the ink jet ink of the present invention, for example, an ink jet recorded image is obtained by ejecting ink from an ink jet head based on a digital signal and adhering it to a recording medium by a printer loaded with the ink jet ink. In order to quickly and surely dry the ink adhered to the recording medium, a method of forming an image by increasing the surface temperature of the recording medium is preferable.

  The surface temperature is adjusted according to the durability of the recording medium and the drying property of the ink used, but is preferably 40 to 100 ° C. In particular, when polyvinyl chloride is used as the recording medium, increasing the surface temperature improves the wettability of the ink with respect to the surface of the recording medium. Therefore, it is more preferable to increase the surface temperature for recording.

  Depending on the brand of the recording medium made of polyvinyl chloride, there may be a difference in wettability and ink drying, so the surface temperature may be adjusted according to the characteristics of each medium.

  In the case where recording is performed by increasing the surface temperature of the recording medium, it is preferable to mount a heater on the ink jet recording apparatus, and heating the recording medium before or during conveyance of the recording medium, the surface temperature of the recording medium can be adjusted by itself. It is possible to adjust.

  As a recording medium used in the ink jet recording method of the present invention, it is preferable to use polyvinyl chloride. Specific examples of the recording medium made of polyvinyl chloride include SOL-371G, SOL-373M, SOL-4701 (manufactured by Big Technos), glossy vinyl chloride (manufactured by Systemgraph Co., Ltd.), KSM-VS, KSM-VST, KSM-VT (above, Kimoto Co., Ltd.), J-CAL-HGX, J-CAL-YHG, J-CAL-WWWG (above, Kyosho Osaka Co., Ltd.), BUS MARK V400 F vinyl, litecal V-600F VINYL (above, manufactured by Flexcon), FR2 (manufactured by Hanwha), LLBAU13713, LLSP20133 (above, manufactured by Sakurai), P-370B, P-400M (above, manufactured by Kambo Plus), S02P, S12P, S13P, S14P, S22P, S24P , S34P, S27P (above, Gr manufactured by FITYP), P-223RW, P-224RW, P-249ZW, P-284ZC (above, manufactured by Lintec), LKG-19, LPA-70, LPE-248, LPM-45, LTG-11, LTG-21 ( As described above, manufactured by Shinsei Co., Ltd., MPI3023 (produced by Toyo Corporation), Napoleon Gloss PVC (manufactured by Futatsu Electronics Co., Ltd.), JV-610, Y-114 (above, produced by ICC), NIJ-CAPVC, NIJ SPVCGT (Nichie), 3101 / H12 / P4, 3104 / H12 / P4, 3104 / H12 / P4S, 9800 / H12 / P4, 3100 / H12 / R2, 3101 / H12 / R2, 3104 / H12 / R2 , 1445 / H14 / P3, 1438 / One Way Visi n (above, manufactured by Inetrcoat), JT5129PM, JT5728P, JT5822P, JT5829P, JT5829R, JT5829PM, JT5829RM, JT5929PM (above, manufactured by Mactac), MPI1005, MPI1900, MPI2000, MPI2001, MPI2002, MPI2001, MPI2002, MPI2002, MPI2002, MPI2002, MPI2002 Avery), AM-101G, AM-501G (above, manufactured by Silver One), FR2 (made by Hanwha Japan), AY-15P, AY-60P, AY-80P, DBSP137GGH, DBSP137GGL (above, manufactured by Insight Inc.) ), SJT-V200F, SJT-V400F-1 (above, manufactured by Horioka Oryome), SPS-98, SPSM-98, SPSH-98, SVGL-137, SVGS-137, MD3-200, MD3-301M, MD5-100, MD5-101M, MD5-105 (manufactured by Metamark), 640M, 641G, 641M, 3105M, 3105SG, 3162G, 3164G, 3164M, 3164XG, 3164XM, 3165G, 3165SG, 3165M, 3169M, 3451SG, 3551G, 3551M, 3631, 3641M, 3651G, 3651M, 3651SG, 3951G, 3641M (above, manufactured by Orafol), SVTL-HQ130 (manufactured by Lamy Corporation), SP300 GWF, SPCLEARAD vinyl (above, manufactured by Catalina), RM-SJR (manufactured by Ryoyo Corporation), Hi Lucky, New Lucky P VC (above, manufactured by LG), SIY-110, SIY-310, SIY-320 (above, manufactured by Sekisui Chemical Co., Ltd.), PRINT MI Frontlit, PRINT XL Light weight banner (above, manufactured by Endexex), RIJET 100, RIJET 145, RIJET 165 (manufactured by Ritrama), NM-SG, NM-SM (manufactured by Nichiei Kako), LTO3GS (manufactured by Lucio Co., Ltd.), easy print 80, performance print 80 (manufactured by Jetgraph), DSE 550, DSB 550, DSE 800G, DSE 802/137, V250WG, V300WG, V350WG (above, manufactured by Hexis), Digital White 6005PE, 6010PE (above, made by Multifix), etc. It is.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated concretely, this invention is not limited to these. In addition, although the display of "part" or "%" is used in an Example, unless otherwise indicated, "part by mass" or "mass%" is represented.

  Further, the pigment dispersant and fixing resin described below were used after diluting the low boiling point solvent by distillation under reduced pressure and diluting with an organic solvent used for dispersion so that the solid content was 20% by mass. Hereinafter, the amounts of the pigment dispersant and the fixing resin used represent solid content conversion values.

Example 1
<Preparation of ink>
[Preparation of Ink 1]
<Preparation of pigment dispersion 1>
C. I. 10 parts of Pigment Blue 15: 3 (hereinafter abbreviated as PB15: 3), 5 parts of Solspers 24000 (manufactured by ICI Japan) as a pigment dispersant, 10 parts of sulfolane as Compound (A), A horizontal bead mill (system zeta manufactured by Ashizawa Co., Ltd.) in which 10 parts of ethylene glycol diacetate as a solvent (B) and 75 parts of diethylene glycol diethyl ether as a solvent (C) are mixed and filled with zirconia beads having a diameter of 0.5 mm at a volume ratio of 60%. And then the zirconia beads were removed to obtain Pigment Dispersion 1.

<Preparation of resin solution 1>
10 parts of sulfolane as the compound (A), 10 parts of ethylene glycol diacetate as the solvent (B), 70 parts of diethylene glycol diethyl ether as the solvent (C), and vinyl chloride-vinyl acetate synthesized by a solution polymerization method as a fixing resin A resin solution 1 was prepared by mixing and dissolving 10 parts of a system copolymer (trade name: VMCH molecular weight: 27000, manufactured by Dow Chemicals).

<Preparation of ink>
While stirring 50 parts of the resin solution 1, 50 parts of the pigment dispersion 1 was added and mixed, and then filtered through a 0.8 μm filter to obtain ink 1.

[Preparation of inks 2 to 14]
In the preparation of the ink 1, the content of the compound (A), the fixing resin type, the type and addition amount of the solvent (B), the type and addition amount of the solvent (C), the type and addition amount of other solvents are shown in Table 1. Inks 2 to 14 were prepared in the same manner except that the changes were made as described above.

[Preparation of Ink 15]
Ink 15 was prepared in the same manner as in Preparation of Ink 1 except that N-methylpyrrolidone was used instead of sulfolane.

<Moisture content>
The water content of inks 1 to 15 was measured by the Karl Fischer method. The water content was adjusted to the water content shown in Table 1 by heating after ink preparation.

  In addition, the detail of each additive described by the abbreviation in Table 1 is as follows. In addition, the numerical value of content of Table 1 is the mass%.

(Fixing resin)
PVC: solution polymerization vinyl chloride-vinyl acetate copolymer (trade name VMCH, manufactured by Dow Chemicals, number average 000 molecular weight 27000)
sPVC: Suspension polymerization vinyl chloride-vinyl acetate copolymer (trade name SOLBIN CL, manufactured by Nissin Chemical, number average molecular weight 25000)
Acrylic: butyl methacrylate-methyl methacrylate copolymer (trade name DEGLAN P24 made by Degussa)
(Solvent (B))
EGDAc: ethylene glycol diacetate PGDAc: propylene glycol diacetate (solvent (C))
DEGDEE: Diethylene glycol diethyl ether DEGDME: Diethylene glycol dimethyl ether (other solvents)
TEGDME: Tetraethylene glycol dibutyl ether NMP: N-methylpyrrolidone.

[Evaluation of ink]
Each of the inks prepared above was evaluated according to the following method.

<Evaluation of intermittent injection>
Piezo head having nozzle diameter of 28 μm, driving frequency of 10 kHz, number of nozzles of 512, minimum liquid amount of 14 pl, nozzle density of 180 dpi (dpi represents the number of dots per 2.54 cm), and Japanese Patent Application Laid-Open No. 2002-363469 Using the strobe light emission type ink flight observation device shown in FIG. 2, the ejection cycle and the light emission cycle are synchronized, and the flight status of each ink is monitored by a CCD camera, and the ejection properties in an environment of 25 ° C. and 55% RH are as follows. Evaluation was made according to criteria.

◎: Ink droplets are ejected normally, and no abnormalities such as bending, chipping, or speed variation occur even if ejection is resumed after stopping for 120 seconds. ○: Ink droplets are ejected normally and emitted. No problem occurs when restarting after stopping for 90 seconds, but there is a nozzle that bends and has a speed variation when restarting after stopping for 3 minutes. Δ: Ink droplets are ejected normally, but ejection There are nozzles that bend and vary in speed when resuming after stopping for 60 seconds. X: There are nozzles that are difficult to normally eject ink droplets and cause bending, and many nozzles when ejection is resumed after stopping for 60 seconds. Bending, speed variation, and missing.

<Evaluation of continuous injection>
The continuous injection property was evaluated using the same device as the intermittent injection property described above.

A: Ink droplets are normally ejected even after continuous ejection for 1 hour, and there are no abnormalities such as bending, chipping, and speed variation. O: Ink droplets are ejected normally after continuous 30-minute ejection, but continuous Bending and velocity variation occurs after 1 hour ejection. Δ: Bending and velocity variation occurs after continuous 30 minute ejection. ×: Normal ejection of ink droplets is difficult, and there are nozzles that cause bending, and continuous 30 minute ejection. After that, nozzle missing occurs.

<Evaluation of satellite generation rate>
Using an apparatus similar to the intermittent ejection evaluation described above, the ink droplet velocity at the time when the ink droplet flew about 1 mm from the nozzle opening and the droplet velocity at which satellites started to be generated were evaluated.

A: Ink droplets are ejected normally, and no satellite is generated even when the droplet velocity is 5 m / s or more. O: Ink droplets are ejected normally, even when the droplet velocity is 3 m / s or more. Satellites are not generated, but satellites are generated at a droplet velocity of 5 m / s. Δ: Ink droplets are normally ejected, but satellites are not generated even at a droplet velocity of 2 m / s or more. Satellites are generated at a droplet velocity of 3 m / s. X: Ink droplets are difficult to eject normally, and there are nozzles that bend, and the satellite generation rate cannot be measured.

<Evaluation of long-term durability of the head>
Fifteen ink jet heads were prepared, inks 1 to 15 were filled in the respective heads, and stored at 40 ° C. in that state. The ink jet head was incorporated into a recording device once a week, and the image formation was performed for 3 months. Next, the long-term durability of the inkjet head was determined by evaluating an image formed after the lapse of 3 months. A performance of △ or higher was regarded as an acceptable level.

A: The image after 3 months and the initial image are the same, and the inkjet head has not deteriorated. ○: The density variation is observed in a part of the image after 3 months, but it is almost the same as the initial image. Identical and almost no deterioration of the inkjet head Δ: Slight white streaks appear in the image after 3 months, and partial deterioration of the inkjet head is observed ×: After 3 months In this image, white streaks occur frequently, and the inkjet head is greatly deteriorated.

<Evaluation of continuous ejection properties and satellite generation speed before and after long-term storage of ink>
As a low temperature storage ink, an ink stored for 4 weeks in a -10 ° C environment was prepared. An ink stored for 4 weeks in a 40 ° C. environment was prepared as a high temperature storage product ink. The continuous ejection properties and the satellite generation rate of the low temperature storage ink and the high temperature storage ink were evaluated.

<Evaluation of odor resistance>
Put each ink 1 to 15 into a 500 ml polyethylene bottle to about half, evaluate the odor by 10 subjects, 5 points when judged almost odorless, 1 point when judged very unpleasant odor As a result, the odor resistance was evaluated according to the following criteria.

A: The average score of 20 subjects is 4.0 points or more. ○: The average score of 20 subjects is 3.0 points or more and less than 4.0 points. Δ: The average score of 20 subjects is 2.0 points or more and less than 3.0 points x: The average score of 20 subjects is less than 2.0 points.

[Image formation]
Each ink is supplied to an on-demand type ink jet printer equipped with a piezo head having a nozzle diameter of 28 μm, a driving frequency of 15 kHz, a nozzle number of 512, a minimum liquid amount of 14 pl, a nozzle density of 180 dpi, and a heater having a maximum recording density of 1440 × 1440 dpi. Was loaded. Next, each ink was ejected, and a solid image of 10 cm × 10 cm was recorded on JT5929PM (manufactured by Mactac) which is a recording medium made of polyvinyl chloride. During printing, the recording medium was heated from the back side, and the heater temperature was set so that the surface temperature of the recording medium during image recording was 45 ° C. The surface temperature of the recording medium was measured using a non-contact thermometer (IT-530N type, manufactured by Horiba, Ltd.).

  According to the above method, each image created from the inks 1 to 15 was evaluated according to the following method. In all cases, the performance of Δ or higher was regarded as an acceptable level.

<Evaluation of dryness>
After recording an image on polyvinyl chloride, the solid image was rubbed with a finger and the quick drying property was evaluated according to the following criteria.

◎: The time when an image cannot be taken even if rubbed with a finger is less than 3 minutes immediately after image recording. ○: The time when an image cannot be taken even if rubbed with a finger is 3 minutes or more and less than 4 minutes immediately after image recording. The time when the image cannot be taken even if it is rubbed by 4 to 4 minutes or more and less than 5 minutes immediately after the image recording is taken.

<Evaluation of fixability>
The surface of the image recorded on polyvinyl chloride was rubbed with dry cotton, and scratch resistance was evaluated according to the following criteria.

◎: Image hardly changes even after rubbing 51 times or more ○: Slight scratch remains at the stage of rubbing 50 times, but hardly affects the image density Δ: Image density decreases during rubbing 20 to 49 times Yes: Image density decreases while rubbing less than 20 times.

  From Table 2, it can be seen that the ink of the present invention is superior to the comparative ink in all evaluation items.

Claims (9)

A compound (A) comprising at least a pigment, a fixing resin, one or more compounds selected from the group of compounds represented by the following general formulas (1) and (2), and a compound represented by the following general formula (3) A solvent (B) comprising one or more compounds selected from the group, the content of the compound (A) is 1.5% by mass or more and 30% by mass or less, and the water content is 0.5%. The non-aqueous inkjet ink characterized by being 4% or less.

^(Wherein, R 1, ^{R 2} are each carbon atoms represent a 1-6 substituents may be bonded by ^{R 1} and ^{R 2} form a ring.)

(In the formula, R ³ and R ⁴ each represent a substituent having 1 to 6 carbon atoms, and R ³ and R ⁴ may be bonded to form a ring.)

(In the formula, R ⁷ and R ⁸ each represent a methyl group or an ethyl group, and OX ² represents an oxyethylene group or an oxypropylene group.) The non-aqueous inkjet ink according to claim 1, wherein the content of the solvent (B) is 1% by mass or more and 30% by mass or less. The non-aqueous inkjet ink according to claim 1 or 2, wherein the solvent (B) is at least one selected from ethylene glycol diacetate and propylene glycol diacetate. Furthermore, the solvent (C) which consists of 1 or more types of compounds chosen from the compound group represented by following General formula (4) is contained, The non-aqueous type | system | group of any one of Claims 1-3 characterized by the above-mentioned. Inkjet ink.

(In the formula, R ⁵ and R ⁶ each represent a methyl group or an ethyl group, and OX ¹ represents an oxyethylene group or an oxypropylene group.) The non-aqueous inkjet ink according to claim 4, wherein the content of the solvent (C) is 50% by mass or more and 90% by mass or less. The non-aqueous inkjet ink according to claim 4 or 5, wherein the solvent (C) is at least one selected from diethylene glycol diethyl ether, dipropylene glycol dimethyl ether, and dipropylene glycol diethyl ether. The non-aqueous inkjet ink according to claim 1, wherein the fixing resin is a resin synthesized by a solution polymerization method. Vinyl chloride-vinyl acetate copolymer, vinyl chloride-vinyl acetate-maleic anhydride copolymer, vinyl chloride-vinyl acetate-vinyl alcohol copolymer, and chloride, wherein the fixing resin has a number average molecular weight in the range of 10,000 to 30,000. The non-aqueous inkjet ink according to any one of claims 1 to 7, wherein the non-aqueous inkjet ink is at least one selected from vinyl-vinyl acetate-hydroxyalkyl acrylate copolymers. 9. An ink jet recording method comprising recording on polyvinyl chloride as a recording medium using the non-aqueous ink jet ink according to any one of claims 1 to 8.