JP2009262334A - Inkjet recording method and recording product - Google Patents

Abstract

There is provided an ink jet recording method capable of realizing high-definition printing excellent in ejection stability and having no uneven density, bleeding, and color mixing even on a recording medium having substantially no ink absorbing layer such as a plastic film. It has been demanded.
An ink jet recording method for performing printing by ejecting droplets of a water-based ink composition onto a recording medium having a recording surface made of a plastic film and attaching the droplets to the recording surface, wherein the water-based ink composition includes: A coloring agent, 0.1 wt% to 1.5 wt% of a silicon-based surfactant, 0.01 wt% to 1 wt% of a diacetylene tetraol represented by the formula (1), a pyrrolidone derivative, a thermoplastic resin, And an aqueous ink composition containing at least water and heating the aqueous ink composition adhered to the recording surface to 40 ° C. or higher.
[Selection figure] None

Description

  The present invention relates to an ink jet recording method for printing on a recording medium whose recording surface is a plastic film (that is, non-coated plastic media, etc.) using a water-based ink composition. The present invention relates to a water-based ink composition with little color mixing and excellent discharge stability and an ink jet recording method using the same.

  The ink jet recording method is a recording method in which recording is performed by causing ink droplets to fly (discharge) and adhere to a recording medium such as paper. Due to recent advances in inkjet recording technology, the field of image recording (printing) that offset printing has been responsible for, especially for recording media whose recording surface is a plastic film (ie, non-coated plastic media, etc.) Printing using an inkjet recording method has been studied. In this case, the recording method and the ink composition used are uniformly wet without ink being repelled on the film (that is, less uneven density), less color mixing and bleeding between different colors, and flying. There are demands for ink droplets that can be stably ejected for a long period of time without bending or clogging (that is, good ejection stability), and many techniques have been studied for that purpose.

  For example, JP 2004-114691 A (Patent Document 1) uses an aqueous inkjet ink composition comprising a polymer latex containing at least one kind of vinyl halide monomer, a surfactant, a wetting agent, and a pigment. Thus, an ink jet recording method for printing on an ink jet recording element with a heating step has been proposed. In this document, when this method is used, water fastness, light fastness and abrasion resistance are good, and it has good adhesion to non-absorbing substrates such as untreated vinyl derivatives. There is a description that a recorded matter can be obtained.

  Japanese Patent Application Laid-Open No. 2004-176057 (Patent Document 2) includes an aqueous emulsion polymer having a glass transition temperature (hereinafter referred to as “Tg”) of −40 ° C. to 150 ° C., a pigment, and a water-soluble surface agent. Ink jet ink compositions and methods for forming images on hydrophobic surfaces using the ink compositions have been proposed. This document describes that as an image forming method, a recording medium having a hydrophobic surface is heated in advance and then an image is formed with the ink composition, which is advantageous in improving fixability and image quality. .

  JP-A-2006-22328 (Patent Document 3) discloses an aqueous inkjet ink composition comprising an aqueous vehicle, a self-dispersing pigment, a silicon-containing surfactant, and a polymer having a Tg of −40 ° C. to 150 ° C. And a method of forming an image on a hydrophobic surface using the ink composition. This document describes that as an image forming method, a recording medium having a hydrophobic surface is heated in advance and then an image is formed with the ink composition, which is advantageous in improving fixability and image quality. .

  Japanese Patent Application Laid-Open No. 2004-250659 (Patent Document 4) discloses an ink-jet ink composition containing a polymer binder composed of polymer nanoparticles having an average particle diameter of 1 nm to 50 nm containing 1% by weight to 20% by weight of a curable composition. And an image forming method using the ink have been proposed. This document describes that the ink is cured by applying heat and radiation after the image is formed with the ink and the abrasion resistance is improved.

  Further, JP-A-10-279871 (Patent Document 5) discloses an ink composition containing a colorant, a wetting agent such as polyorganosiloxane, a lactam such as 2-pyrrolidone, and a penetrating agent such as 1,2-alkyldiol. Things have been proposed. This document describes that the ink composition is free from bending and clogging of ink droplets, has good ejection stability, and is suitable for an ink jet recording system.

JP 2004-114691 A JP 2004-176057 A JP 2006-22328 A JP 2004-250659 A Japanese Patent Laid-Open No. 10-279871

  However, the above prior art has the following problems.

  JP 2004-114691 A (Patent Document 1), JP 2004-176057 A (Patent Document 2), JP 2006-22328 A (Patent Document 3), JP 2004-250659 A (Patent Document 4). When printing on a film using the ink composition shown in (2), there is a problem that the printed image is disturbed due to the occurrence of uneven density, color mixing and bleeding on the printed matter. In addition, when the ink composition is ejected by the ink jet recording method, there is a problem that flying droplets of ink droplets and clogging are likely to occur, and the printed image is thereby disturbed.

  Further, in the ink composition disclosed in Japanese Patent Application Laid-Open No. 10-279871 (Patent Document 5), the ink does not stay on the film having no ink absorbing layer and the image cannot be formed, and the image fixing property is not improved. There was a problem that there was not.

  Accordingly, the object of the present invention is to reduce ink density unevenness, bleeding, color mixing, and the like even when printing on a recording medium whose recording surface is a plastic film (that is, non-coated plastic media), and to improve ejection stability. An object is to provide an excellent aqueous ink composition and an ink jet recording method using the same.

  The ink jet recording method according to the present invention is an ink jet recording method in which droplets of a water-based ink composition are ejected onto a recording medium whose recording surface is a plastic film and adhered to the recording surface, and printing is performed. As a composition, a coloring agent, 0.1% by weight to 1.5% by weight of a silicon surfactant, 0.01% by weight to 1% by weight of a diacetylene tetraol represented by the following formula (1), a pyrrolidone derivative Using a water-based ink composition containing at least a thermoplastic resin and water, and heating the water-based ink composition adhered to the recording surface to 40 ° C. or higher.

  In the inkjet recording method of the invention, the silicon surfactant is a polysiloxane compound, and the pyrrolidone derivative is N-methyl-2-pyrrolidone.

  In the ink jet recording method of the invention, the amount of the pyrrolidone derivative added to the aqueous ink composition is 2.0% by weight to 25.0% by weight.

  The ink jet recording method of the invention is characterized in that the colorant is a pigment and the pigment is dispersed in an aqueous ink composition.

  The ink jet recording method of the present invention is characterized in that the water-based ink composition further contains a penetrating solvent.

  The ink jet recording method of the present invention is characterized in that the penetrating solvent is selected from at least one selected from the group consisting of 1,2-alkyldiols, glycol ethers, and monohydric alcohols.

  The ink jet recording method of the present invention is characterized in that the water-based ink composition further contains a humectant.

  The ink jet recording method of the present invention is characterized in that the heat treatment is performed by heater heating or hot air drying.

  Furthermore, the recorded matter of the present invention is characterized in that an image is formed using any one of the ink jet recording methods described above.

  In the ink jet recording method of the present invention, even if printing is performed on a recording medium whose recording surface is a plastic film (that is, non-coated plastic media), a recorded matter with less unevenness of ink density, bleeding, color mixing, etc. can be obtained, The aqueous ink composition used is excellent in ejection stability. Therefore, a clear image can be formed even on a plastic film.

  The ink jet recording method according to the present invention is an ink jet recording method in which droplets of a water-based ink composition are ejected onto a recording medium whose recording surface is a plastic film and adhered to the recording surface, and printing is performed. As a composition, a coloring agent, 0.1% by weight to 1.5% by weight of a silicon surfactant, 0.01% by weight to 1% by weight of a diacetylene tetraol represented by the following formula (1), a pyrrolidone derivative Using a water-based ink composition containing at least a thermoplastic resin and water, and heating the water-based ink composition adhered to the recording surface to 40 ° C. or higher.

  The ink jet recording method of the present invention and the constituent materials of the water-based ink composition used in this method will be described below.

[Inkjet recording method]
As described above, the ink jet recording method according to the present invention is performed by ejecting droplets of the aqueous ink composition onto a recording medium whose recording surface is a plastic film and attaching the droplets to the recording surface. At that time, a step of heating the ink droplets adhered to the recording surface to 40 ° C. or higher is included. By doing this, the liquid medium (mainly water, solvent, etc.) contained in the water-based ink composition adhering to the recording surface is evaporated and drying is promoted, and further the thermoplasticity contained in the water-based ink composition. A resin film (resin film) is formed. Therefore, by printing with this method, when an image is formed on a recording medium having substantially no ink absorbing layer such as a plastic film, drying is fast even if a large amount of ink is adhered to obtain a dark print density. Therefore, a clear image with little shading unevenness / bleeding can be obtained, and the resin film is firmly adhered to the recording surface, so that the fixing property of the image is excellent.

(Heating process)
The ink jet recording method of the present invention includes a heating step of heating the water-based ink composition discharged onto the recording surface. If the heating temperature to the water-based ink composition in this heating step is 40 ° C. or higher, the above-described effects can be obtained, but a range of 40 ° C. to 80 ° C. is preferable, and a range of 45 ° C. to 60 ° C. is more preferable. When the heating temperature exceeds 80 ° C., the plastic film used as the recording medium may be softened or deformed, which may hinder the conveyance of the recording medium after the heating process, or the recording medium may reach room temperature after the heating process. When it cools down, there are cases where problems such as shrinkage occur.

  In the present invention, “to heat” or “to heat at the time of printing” includes the case where the water-based ink composition is subjected to a heat treatment almost simultaneously with the adhesion to the recording surface of the recording medium. A case where the recording medium is pre-heated before the water-based ink composition is deposited on the recording surface, or a case where the recording medium is heat-treated after the water-based ink composition is deposited on the recording surface. Shall also be included.

  As a heating means in this heating step, a conventional method such as an infrared heating device or a hot air heating device can be used. Using these apparatuses, a method for printing with a water-based ink composition by heating a recording medium in advance, a method for printing with a water-based ink composition while heating by incorporating a heater or the like on the back of the recording medium, A method of heating the recording medium after printing, a method of combining a plurality of heating means described above, or the like can be used.

  The heating time in this heating step is not particularly limited as long as the liquid medium in the aqueous ink composition evaporates and a film of a thermoplastic resin can be formed, but preferably 10 seconds to 1 day. Preferably, it is in the range of 30 seconds to 10 hours. Within this range, the liquid medium type, thermoplastic resin type, and printing speed to be used can be set as appropriate.

  Here, as a recording medium used in the ink jet recording method according to the present invention, plastic is coated on a substrate such as a plastic film or paper that is not subjected to surface treatment for ink jet printing (that is, an ink absorbing layer is not formed). And those to which a plastic film is bonded. Examples of the plastic here include polyvinyl chloride, polyethylene terephthalate, polycarbonate, polystyrene, polyurethane, polyethylene, and polypropylene.

(Ink ejection method)
As the ink jet recording method of the present invention, any method can be used as long as it is a system in which an aqueous ink composition, which will be described in detail later, is ejected as droplets from a fine nozzle and the droplets are attached to a recording medium. . To explain some of them, there is an electrostatic attraction method. This method applies a strong electric field between the nozzle and the acceleration electrode placed in front of the nozzle, and continuously injects ink from the nozzle in the form of droplets. There is a method in which a print information signal is applied to the deflection electrode while the ink droplet is flying between the deflection electrodes and recorded, or a method in which the ink droplet is ejected in response to the print information signal without being deflected.

  The second method is a method in which ink droplets are forcibly ejected by applying pressure to the ink liquid with a small pump and mechanically vibrating the nozzle with a crystal resonator or the like. The ejected ink droplet is charged simultaneously with the ejection, and a printing information signal is given to the deflection electrode and recorded while the ink droplet flies between the deflection electrodes.

  The third method is a method using a piezoelectric element, in which a pressure and a print information signal are simultaneously applied to an ink liquid using a piezoelectric element, and ink droplets are ejected and recorded.

  The fourth method is a method in which the ink liquid is rapidly expanded in volume by the action of heat energy, and the ink liquid is heated and foamed with a microelectrode in accordance with a print information signal to eject and record ink droplets.

[Water-based ink composition]
The water-based ink composition used in the ink jet recording method of the present invention includes a colorant, 0.1 wt% to 1.5 wt% of a silicon surfactant, 0.01 wt% to 1 wt% of the following formula (1 At least a diacetylenetetraol, a pyrrolidone derivative, a thermoplastic resin, and water.

  Each constituent material will be described in detail below.

(Coloring agent)
Examples of the colorant used in the aqueous ink composition according to the present invention include dyes and pigments. Among these, pigments have the property that they are insoluble or hardly soluble in water and hardly fade by light or gas. Therefore, a recorded matter printed with an ink composition using the same is preferable in the present invention because it has excellent water resistance, gas resistance, light resistance and the like and good storage stability.

  As the pigment that can be used in the present invention, any of known inorganic pigments, organic pigments, and carbon black can be used. Among these, carbon black and organic pigments are particularly preferable from the viewpoints of good color development and low sedimentation and difficulty in sedimentation during dispersion.

  In the present invention, specific examples of preferable carbon black include furnace black, lamp black, acetylene black, channel black and the like (CI Pigment Black 7). 2300, 900, MCF88, no. 20B, no. 33, no. 40, no. 45, no. 52, MA7, MA8, MA100, No2200B, etc. (all trade names, manufactured by Mitsubishi Chemical Corporation), color black FW1, FW2, FW2V, FW18, FW200, S150, S160, S170, Pretex 35, U, V, 140U , Special Black 6, 5, 4A, 4, 250, etc. (all trade names, manufactured by Degussa), Conductex SC, Raven 1255, 5750, 5250, 5000, 3500, 1255, 700, etc. (all trade names, Colombia) (Manufactured by Carbon Co., Ltd.), Regar 400R, 330R, 660R, Mogul L, Monarch 700, 800, 880, 900, 1000, 1100, 1300, 1400, Elftex 12, etc. (all trade names, manufactured by Cabot Corporation). In addition, these are description of an example of the carbon black suitable for this invention, and this invention is not limited by these. These carbon blacks may be used alone or as a mixture of two or more. These carbon blacks are added in an amount of 0.5 to 20% by weight, preferably 1 to 10% by weight, based on the total amount of the black ink composition.

  Preferred organic pigments in the present invention include quinacridone pigments, quinacridone quinone pigments, dioxazine pigments, phthalocyanine pigments, anthrapyrimidine pigments, ansanthrone pigments, indanthrone pigments, flavanthrone pigments, perylene pigments And diketopyrrolopyrrole pigments, perinone pigments, quinophthalone pigments, anthraquinone pigments, thioindigo pigments, benzimidazolone pigments, isoindolinone pigments, azomethine pigments and azo pigments.

  Specific examples of the organic pigment used in the water-based ink composition according to the present invention include the following.

  Examples of the pigment used in the cyan ink composition include C.I. I. Pigment blue 1, 2, 3, 15: 3, 15: 4, 15:34, 16, 22, 60, etc .; C.I. I. Bat blue 4, 60 and the like, preferably C.I. I. Pigment Blue 15: 3, 15: 4, and 60 selected from the group consisting of 60 or more. These pigments are contained in an amount of about 0.5 to 20% by weight, preferably about 1 to 10% by weight, based on the total amount of the cyan ink composition.

  Examples of the pigment used in the magenta ink composition include C.I. I. Pigment Red 5, 7, 12, 48 (Ca), 48 (Mn), 57 (Ca), 57: 1, 112, 122, 123, 168, 184, 202, C.I. I. Pigment violet 19 and the like, preferably C.I. I. Pigment red 122, 202, and 209, C.I. I. These are single or a mixture of two or more selected from the group consisting of CI Pigment Violet 19. These pigments are contained in an amount of about 0.5 to 20% by weight, preferably about 1 to 10% by weight, based on the total amount of the magenta ink composition.

  Examples of the pigment used in the yellow ink composition include C.I. I. Pigment Yellow 1, 2, 3, 12, 13, 14C, 16, 17, 73, 74, 75, 83, 93, 95, 97, 98, 119, 110, 114, 128, 129, 138, 150, 151, 154, 155, 180, 185, etc., preferably C.I. I. These are single or a mixture of two or more selected from the group consisting of CI Pigment Yellow 74, 109, 110, 128, and 138. These pigments are contained in an amount of about 0.5 to 20% by weight, preferably about 1 to 10% by weight, based on the total amount of the yellow ink composition.

  Examples of the pigment used in the orange ink composition include C.I. I. Pigment Orange 36 or 43, or a mixture thereof. These pigments are contained in an amount of about 0.5 to 20% by weight, preferably about 1 to 10% by weight, based on the total amount of the orange ink composition.

  Examples of the pigment used in the green ink composition include C.I. I. Pigment Green 7 or 36 or a mixture thereof. These pigments are contained in an amount of about 0.5 to 20% by weight, preferably about 1 to 10% by weight, based on the total amount of the green ink composition.

  In order to apply the above-described pigments to the aqueous ink composition according to the present invention, it is necessary that the pigments can be stably dispersed and held in water. As the method, a method of dispersing with a water-soluble resin and / or a resin dispersant of a water-dispersible resin (hereinafter, the pigment dispersed by this method is referred to as “resin-dispersed pigment”), a water-soluble surfactant. And / or a method of dispersing with a surfactant of a water-dispersible surfactant (hereinafter, a pigment dispersed by this method is referred to as “surfactant-dispersed pigment”), and hydrophilic functional groups are formed on the surface of pigment particles. A method of chemically and physically introducing and making it dispersible and / or soluble in water without a dispersant such as the above-mentioned resin or surfactant (hereinafter, the pigment dispersed by this method is referred to as “surface-treated pigment”. To be described). For the water-based ink composition according to the present invention, any of the above-mentioned resin-dispersed pigments, surfactant-dispersed pigments, and surface-treated pigments can be used, and a plurality of types can be used as necessary.

Examples of the resin dispersant used in the resin dispersion pigment include polyvinyl alcohols, polyvinylpyrrolidones, polyacrylic acid, acrylic acid-acrylonitrile copolymer, vinyl acetate-acrylic acid ester copolymer, acrylic acid-acrylic acid ester copolymer. Polymer, styrene-acrylic acid copolymer, styrene-methacrylic acid copolymer, styrene-methacrylic acid-acrylic acid ester copolymer, styrene-α-methylstyrene-acrylic acid copolymer, styrene-α-methylstyrene -Acrylic acid-acrylic acid ester copolymer, styrene-maleic acid copolymer, styrene-maleic anhydride copolymer, vinylnaphthalene-acrylic acid copolymer, vinylnaphthalene-maleic acid copolymer, vinyl acetate-maleic acid Acid ester copolymer, vinyl acetate-crotonic acid copolymer Body, vinyl acetate-acrylic acid copolymer, and salts thereof. Among these, a copolymer of a monomer having a hydrophobic functional group and a monomer having a hydrophilic functional group, and a polymer comprising a monomer having both a hydrophobic functional group and a hydrophilic functional group are particularly preferable. As the form of the copolymer, any form of a random copolymer, a block copolymer, an alternating copolymer, and a graft copolymer can be used.
Examples of the salt include bases such as ammonia, ethylamine, diethylamine, triethylamine, propylamine, isopropylamine, dipropylamine, butylamine, isobutylamine, diethanolamine, triethanolamine, tri-iso-propanolamine, aminomethylpropanol, and morpholine. And a salt with a functional compound. The amount of these basic compounds added is not particularly limited as long as it is not less than the neutralization equivalent of the resin dispersant.

  The molecular weight of the resin dispersant described above is preferably in the range of 1,000 to 100,000 as the weight average molecular weight, and more preferably in the range of 3,000 to 10,000. When the molecular weight is in the above range, stable dispersion of the pigment in water can be obtained, and viscosity control when applied to the aqueous ink composition is easy.

  Moreover, it is preferable that it is the range of 50-300 as an acid value, and it is more preferable that it is the range of 70-150. When the acid value is within this range, the dispersibility of the pigment particles in water can be stably secured, and the water resistance of a recorded matter printed with an aqueous ink composition using the pigment particle is good.

  Commercially available products can be used as the resin dispersant described above. Specifically, Joncryl 67 (weight average molecular weight: 12,500, acid value: 213), Joncryl 678 (weight average molecular weight: 8,500, acid value: 215), Joncryl 586 (weight average molecular weight: 4,600) , Acid value: 108), joncryl 611 (weight average molecular weight: 8,100, acid value: 53), joncryl 680 (weight average molecular weight: 4,900, acid value: 215), joncryl 682 (weight average molecular weight) : 1,700, acid value: 238), joncryl 683 (weight average molecular weight: 8,000, acid value: 160), joncryl 690 (weight average molecular weight: 16,500, acid value: 240) , Manufactured by BASF Japan Ltd.).

  The surfactant used in the surfactant-dispersed pigment includes alkane sulfonate, α-olefin sulfonate, alkyl benzene sulfonate, alkyl naphthalene sulfonate, acylmethyl taurate, dialkyl sulfosuccinate, Anionic surfactants such as alkyl sulfate ester salts, sulfated olefins, polyoxyethylene alkyl ether sulfate ester salts, alkyl phosphate ester salts, polyoxyethylene alkyl ether phosphate ester salts and monoglycerite phosphate ester salts, alkyl Amphoteric surfactants such as pyridium salt, alkylamino acid salt, alkyldimethylbetaine, polyoxyethylene alkyl ether, polyoxyethylene alkylphenyl ether, polyoxyethylene alkyl ester, polyoxyethylene Rukiruamido, glycerol alkyl esters, nonionic surfactants such as sorbitan alkyl esters.

  The amount of the resin dispersant and surfactant added to the pigment described above is preferably 1% by weight to 100% by weight, more preferably 5% by weight to 50% by weight, based on the weight ratio. By being in this range, the dispersion stability of the pigment in water can be ensured.

Moreover, as a surface treatment pigment, as a hydrophilic functional group,
-OM, -COOM, -CO -, - SO 3 M, -SO 2 NH 2, -RSO 2 M,
_{-PO 3 HM, -PO 3 M 2} , -SO 2 NHCOR, -NH 3, -NR 3
(However, M in the formula represents a hydrogen atom, an alkali metal, ammonium, or organic ammonium, and R has an alkyl group having 1 to 12 carbon atoms, a phenyl group that may have a substituent, or a substituent. A naphthyl group which may be present), and the like. These functional groups are physically and / or chemically introduced by grafting directly to the pigment particle surface and / or via other groups. Examples of the polyvalent group include an alkylene group having 1 to 12 carbon atoms, a phenylene group which may have a substituent, or a naphthylene group which may have a substituent.

In addition, as the surface-treated pigment, -SO ₃ M and / or -RSO ₂ M (M is a counter ion, hydrogen ion, alkali metal ion, ammonium ion is added to the pigment particle surface by a treatment agent containing sulfur. Or an organic ammonium ion) that has been surface-treated so as to be chemically bonded, that is, the pigment has no active protons, no reactivity with sulfonic acid, and the pigment is insoluble or hardly soluble. The pigment is dispersed in a solvent, and then the surface treatment is performed so that —SO ₃ M and / or —RSO ₂ M are chemically bonded to the particle surface by amidosulfuric acid or a complex of sulfur trioxide and tertiary amine. In addition, it is preferable that it can be dispersed and / or dissolved in water.

  Various known surface treatment means can be applied as the surface treatment means for grafting the functional group or a salt thereof directly on the surface of the pigment particle or via a polyvalent group. For example, means for treating a commercially available oxidized carbon black with ozone or a sodium hypochlorite solution to further oxidize the carbon black to make the surface more hydrophilic (for example, JP-A-7-258578, JP-A-H10-238707). 8-3498, JP-A-10-120958, JP-A-10-195331, JP-A-10-237349), means for treating carbon black with 3-amino-N-alkyl-substituted pyridium bromide ( For example, JP-A-10-195360 and JP-A-10-330665), an organic pigment is dispersed in a solvent in which the organic pigment is insoluble or hardly soluble, and a sulfone group is introduced onto the pigment particle surface by a sulfonating agent. Means (for example, JP-A-8-283596, JP-A-10-110110, JP-A-10-1101 No. 1), means for dispersing an organic pigment in a basic solvent that forms a complex with sulfur trioxide, treating the surface of the organic pigment by adding sulfur trioxide, and introducing a sulfone group or a sulfonamino group (For example, Unexamined-Japanese-Patent No. 10-110114) etc. are mentioned, However, The preparation means for the surface treatment pigment used by this invention is not limited to these means.

  The functional group grafted on one pigment particle may be single or plural kinds. The type and 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.

  The resin-dispersed pigment, surfactant-dispersed pigment, and surface-treated pigment described above are dispersed in water. For resin-dispersed pigment, pigment, water, and resin, and for surfactant-dispersed pigment, pigment, water, and surfactant. For surface-treated pigments, surface-treated pigment and water, and water-soluble organic solvents / neutralizers, etc., as necessary, are added to the ball mill, sand mill, attritor, roll mill, agitator mill, Henschel mixer, colloid mill, It can be carried out by a conventionally used disperser such as an ultrasonic homogenizer, a jet mill or an ang mill. In this case, the dispersion of the pigment in water is ensured by dispersing the pigment until the average particle size is in the range of 20 nm to 500 nm, more preferably in the range of 50 nm to 200 nm. This is preferable.

(Silicon surfactant)
The water-based ink composition according to the present invention contains a silicon-based surfactant. This silicon-based surfactant has the effect of spreading the ink uniformly on a recording medium such as a plastic film so as not to cause uneven density or bleeding. In order to have such an action, 0.1% to 1.5% by weight of a silicon-based surfactant is added with respect to the total amount of the aqueous ink composition.

  The silicon-based surface activity is preferably a polysiloxane compound, and examples thereof include polyether-modified organosiloxane. Examples of the polyether-modified organosiloxane include compounds represented by the following formula (2).

上記式（２）の構造の化合物中、特にｆ＋ｐの値が１１〜３００の範囲であることが好ましく、１１〜１００の範囲であることがより好ましい。ｆ＋ｐの値が上記範囲であることにより、プラスチックフィルム等の疎水的な表面を持つ記録媒体上でも、本発明による水性インク組成物が弾かれずに均一に付着することができるため、画像に濃淡ムラや滲みが少なくなるという利点がある。このような上記式（２）の構造を持つ化合物は市販されており、本発明による水性インク組成物に好適に用いることができる。詳しくは、ＢＹＫ−３０６、ＢＹＫ−３０７、ＢＹＫ−３３３、ＢＹＫ−３４１、ＢＹＫ−３４５、ＢＹＫ−３４６、ＢＹＫ−３４８（以上商品名、ビックケミー・ジャパン株式会社製）、ＫＦ−３５１Ａ、ＫＦ−３５２Ａ、ＫＦ−３５３、ＫＦ−３５４Ｌ、ＫＦ−３５５Ａ、ＫＦ−６１５Ａ、ＫＦ−９４５、ＫＦ−６４０、ＫＦ−６４２、ＫＦ−６４３、ＫＦ−６０２０、Ｘ−２２−４５１５、ＫＦ−６０１１、ＫＦ−６０１２、ＫＦ−６０１５、ＫＦ−６０１７（以上商品名、信越化学株式会社製）等が挙げられる。

Among the compounds having the structure of the above formula (2), the value of f + p is particularly preferably in the range of 11 to 300, and more preferably in the range of 11 to 100. When the value of f + p is in the above range, the aqueous ink composition according to the present invention can be uniformly attached without being repelled even on a recording medium having a hydrophobic surface such as a plastic film. There is an advantage that bleeding is reduced. Such a compound having the structure of the above formula (2) is commercially available and can be suitably used in the aqueous ink composition according to the present invention. Specifically, BYK-306, BYK-307, BYK-333, BYK-341, BYK-345, BYK-346, BYK-348 (above trade names, manufactured by Big Chemie Japan Co., Ltd.), KF-351A, KF-352A KF-353, KF-354L, KF-355A, KF-615A, KF-945, KF-640, KF-642, KF-643, KF-6020, X-22-4515, KF-6011, KF-6012 , KF-6015, KF-6017 (trade names, manufactured by Shin-Etsu Chemical Co., Ltd.) and the like.

(Diacetylene tetraol)
The water-based ink composition according to the present invention includes diacetylene tetraol represented by the following formula (1).

上記式（１）で表わされるジアセチレンテトラオールは、これを含む水性インク組成物中の微細な泡が大きく成長するのを抑制し、また系外に急速に抜く作用を持つ。さらに、インクジェット記録方式における機器（プリンタ等）のインクが接触する部材との界面張力を適正な範囲にして流動性を向上するという作用を持つ。そのため、インク滴をインクジェット方式により吐出する際、泡によるインク滴の飛行曲がりや抜けが抑制され、長時間に渡って良好な吐出安定性が得られる。また、プラスチックフィルム等の疎水的表面に対しても良好な濡れ剤として作用し、インク−フィルム間に気泡がある場合にもその泡を急速に系外に逃がす作用も大きいため、インクが均一に濡れるようになる。従って、濃淡ムラや滲みの少ない、鮮明な画像の記録物が得られる。そのような作用を持たせるために、水性インク組成物全量に対して０．０１重量％〜１重量％の上記式（１）で表わされるジアセチレンテトラオールが添加される。

The diacetylene tetraol represented by the above formula (1) suppresses the large growth of fine bubbles in the aqueous ink composition containing the diacetylene tetraol, and has an action of rapidly removing out of the system. Furthermore, the fluidity is improved by setting the interfacial tension with a member in contact with ink of an apparatus (printer or the like) in an ink jet recording system to an appropriate range. For this reason, when ink droplets are ejected by the ink jet method, flight bending and omission of ink droplets due to bubbles are suppressed, and good ejection stability can be obtained over a long period of time. In addition, it acts as a good wetting agent on hydrophobic surfaces such as plastic films, and even when there are bubbles between the ink and film, it has a great effect of rapidly releasing the bubbles out of the system, so that the ink is uniform. It gets wet. Accordingly, a clear recorded image with little shading unevenness and bleeding can be obtained. In order to have such an action, 0.01% by weight to 1% by weight of diacetylenetetraol represented by the above formula (1) is added with respect to the total amount of the aqueous ink composition.

  A commercial item can be used as said diacetylene tetraol, For example, Surfynol MD-20 (A brand name, Air Products and Chemicals Inc. product) etc. are mentioned.

(Thermoplastic resin)
The aqueous ink composition according to the present invention includes a thermoplastic resin. This thermoplastic resin solidifies the ink when the aqueous ink composition according to the present invention is printed on a recording medium such as a plastic film that does not have an ink absorbing layer, and further firmly fixes the solidified ink on the film. Has an effect. The thermoplastic resin can be used in a dissolved or dispersed state with respect to the aqueous ink composition according to the present invention. As the resin in the dissolved state, the above-described resin dispersant used when a pigment is dispersed as the colorant of the aqueous ink composition according to the present invention can be used. Further, as the resin in a dispersed state, a resin that is hardly soluble or insoluble in the liquid medium of the aqueous ink composition according to the present invention may be dispersed in the form of fine particles (that is, in an emulsion state or a suspension state). Can do. In the present invention, it is preferable to include the thermoplastic resin in a fine particle dispersed state in consideration of the viscosity, storage stability and ejection characteristics of the aqueous ink composition to be used.

  As the thermoplastic resin used in the present invention, polyacrylic acid ester or copolymer thereof, polymethacrylic acid ester or copolymer thereof, polyacrylonitrile or copolymer thereof, polycyanoacrylate, polyacrylamide, polyacrylic acid, Polymethacrylic acid, polyethylene, polypropylene, polybutene, polyisobutylene, polystyrene or copolymers thereof, petroleum resin, chroman indene resin, terpene resin, polyvinyl acetate or copolymer thereof, polyvinyl alcohol, polyvinyl acetal, polyvinyl ether, Polyvinyl chloride or copolymer thereof, polyvinylidene chloride, fluororesin, fluoro rubber, polyvinyl carbazole, polyvinyl pyrrolidone or copolymer thereof, polyvinyl pyridine, poly Sulfonyl imidazole, polybutadiene or a copolymer, polychloroprene, polyisoprene, can be used natural resins. Of these, those having both a hydrophobic part and a hydrophilic part in the molecular structure are particularly preferred.

  In order to obtain the thermoplastic resin in a fine particle state, the thermoplastic resin is obtained by the following method, and any of these methods may be used, and a plurality of methods may be combined as necessary. As the method, a polymerization catalyst (polymerization initiator) and a dispersing agent are mixed in a monomer constituting a desired thermoplastic resin and polymerized (that is, emulsion polymerization), a thermoplastic resin having a hydrophilic portion. Is obtained by dissolving water in a water-soluble organic solvent and mixing the solution in water, and then removing the water-soluble organic solvent by distillation or the like. The thermoplastic resin is dissolved in a water-insoluble organic solvent and the solution is dissolved in an aqueous solution together with a dispersant. And a method obtained by mixing them. Said method can be suitably selected according to the kind and characteristic of the thermoplastic resin to be used. The dispersant that can be used for dispersing the thermoplastic resin is not particularly limited, but an anionic surfactant (for example, sodium dodecylbenzenesulfonate, sodium lauryl phosphate, polyoxyethylene alkyl ether sulfate) Ammonium salts, etc.), nonionic surfactants (for example, polyoxyethylene alkyl ethers, polyoxyethylene alkyl esters, polyoxyethylene sorbitan fatty acid esters, polyoxyethylene alkyl phenyl ethers, etc.), and these may be used alone or Two or more kinds can be mixed and used.

  As the thermoplastic resin as described above, when it is used in a fine particle state (emulsion form, suspension form), it is also possible to use those obtained by known materials and methods. For example, those described in JP-B-62-1426, JP-A-3-56573, JP-A-3-79678, JP-A-3-160068, JP-A-4-18462 and the like can be used. Good. Commercially available products can also be used. For example, Microgel E-1002, Microgel E-5002 (trade name, manufactured by Nippon Paint Co., Ltd.), Boncoat 4001, Boncoat 5454 (trade name, Dainippon Ink and Chemicals, Inc.) Co., Ltd.), SAE1014 (trade name, manufactured by Nippon Zeon Co., Ltd.), Cybinol SK-200 (trade name, manufactured by Seiden Chemical Co., Ltd.), Jongkrill 7100, Jongkrill 390, Jongkrill 711, Jongkrill 511, Jongkrill 7001, John Crill 632, John Crill 741, John Crill 450, John Crill 840, John Crill 74J, John Crill HRC-1645J, John Crill 734, John Crill 852, John Crill 7600, John Crill 775, John Crill 537J John Crill 1535, John Crill PDX-7630A, John Crill 352J, John Crill 352D, John Crill PDX-7145, John Crill 538J, John Crill 7640, John Crill 7641, John Crill 631, John Crill 790, John Crill 780, John Crill 7610 (trade name, manufactured by BASF Japan Ltd.) and the like.

  When the thermoplastic resin is used in a fine particle state, the average particle diameter is preferably in the range of 5 nm to 400 nm, more preferably in the range of 50 nm to 200 nm, from the viewpoint of ensuring the storage stability and ejection stability of the aqueous ink composition. is there.

  The thermoplastic resin is preferably contained in the range of 0.1% by weight to 15% by weight in terms of solid content with respect to the total amount of the aqueous ink composition, and is contained in the range of 0.5% by weight to 10% by weight. It is preferable. Within this range, the water-based ink composition according to the present invention can be solidified and fixed on a recording medium such as a plastic film that does not have an ink absorbing layer, and the recorded matter has excellent fixability. It becomes. If the addition amount is less than 0.1% by weight, the strength of ink solidification / fixing becomes weak, and it may be easily peeled off from the surface of the plastic film. On the other hand, if the amount added exceeds 15% by weight, the storage stability and ejection stability of the water-based ink composition may not be ensured.

(Pyrrolidone derivative)
The aqueous ink composition according to the present invention comprises a pyrrolidone derivative. This pyrrolidone derivative acts as a good solubilizer / softener for the above-mentioned thermoplastic resin, and promotes the formation of a film by the thermoplastic resin when the ink is heated and dried, thereby promoting the solidification and fixing of the ink on the plastic film. Has an effect.

  Specific examples of pyrrolidone derivatives having such actions include N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, N-vinyl-2-pyrrolidone, 2-pyrrolidone, and N-butyl-2-pyrrolidone. , 5-methyl-2-pyrrolidone and the like. Of these, N-methyl-2-pyrrolidone is particularly preferred from the viewpoint of quick drying of the ink and promotion of film formation of the thermoplastic resin.

  The addition amount of the pyrrolidone derivative is preferably in the range of 2% by weight to 25% by weight, more preferably in the range of 4% by weight to 15% by weight with respect to the total amount of the aqueous ink composition.

(water)
Water is a central medium of the water-based ink composition according to the present invention, and preferable water is ion-exchanged water, ultrafiltered water, reverse osmosis water, distilled water for the purpose of reducing ionic impurities as much as possible. Etc. or ultrapure water can be used. In addition, when water sterilized by ultraviolet irradiation or addition of hydrogen peroxide is used, it is preferable because the generation of mold and bacteria can be prevented when the pigment dispersion and the aqueous ink composition using the same are stored for a long period of time. It is.

  The aqueous ink composition used in the inkjet method of the present invention includes at least the above-described pigment, silicon-based surfactant, diacetylenetetraol represented by the following formula (1), a thermoplastic resin, a pyrrolidone derivative, and water. With this configuration, the storage stability and ejection stability are good, and even on a plastic film, it is possible to form a recorded matter with little shading unevenness and bleeding, and excellent fixability, but in terms of further improving its characteristics, Osmotic solvents, humectants, and other additives can be added.

(Penetration solvent)
The water-based ink composition according to the present invention preferably further contains a penetrating solvent as necessary. This penetrating solvent has the effect of further improving the wettability of the water-based ink composition with respect to the plastic film to uniformly wet it, and is therefore preferable because the water-based ink composition can be further imparted with the effect of reducing density unevenness and bleeding. . It also functions as a solubilizing agent for the diacetylene tetraol represented by the above formula (1) in the aqueous ink composition, so that the diacetylene tetraol can be more effectively contained in the aqueous ink composition. This is preferable. Examples of the penetrating solvent having such an action include 1,2-alkyldiols, glycol ethers, and monohydric alcohols. The aqueous ink composition according to the present invention is selected from at least one kind selected from the group consisting of these. It is preferable that

  As examples of 1,2-alkyldiols, 1,2-alkyldiols having 4 to 8 carbon atoms such as butanediol, pentanediol, hexanediol, heptanediol, and octanediol are preferable. Among these, C6-C8 1,2-hexanediol, 1,2-heptanediol, and 1,2-octanediol are more preferable.

  Examples of glycol ethers include ethylene glycol mono-n-butyl ether, ethylene glycol mono-t-butyl ether, ethylene glycol mono-iso-propyl ether, ethylene glycol mono-n-pentyl ether, ethylene glycol mono-iso-pentyl ether , Ethylene glycol mononeopentyl ether, ethylene glycol mono-n-hexyl ether, ethylene glycol mono-iso-hexyl ether, diethylene glycol mono-n-propyl ether, diethylene glycol mono-iso-propyl ether, diethylene glycol mono-n-butyl ether, diethylene glycol Mono-t-butyl ether, diethylene glycol mono-n-pentyl ether, diethylene glycol Mono-iso-pentyl ether, diethylene glycol mononeopentyl ether, diethylene glycol mono-n-hexyl ether, diethylene glycol mono-iso-hexyl ether, diethylene glycol mono-2-ethylhexyl ether, triethylene glycol mono-n-butyl ether, triethylene glycol mono -N-pentyl ether, triethylene glycol mono-iso-pentyl ether, triethylene glycol mono neopentyl ether, triethylene glycol mono-n-hexyl ether, triethylene glycol mono-iso-hexyl ether, 1-methyl-1- Methoxybutanol, triethylene glycol mono-2-ethylhexyl ether, propylene glycol monomethyl ether Propylene glycol monoethyl ether, propylene glycol mono-t-butyl ether, propylene glycol mono-n-propyl ether, propylene glycol mono-iso-propyl ether, propylene glycol mono-n-butyl ether, propylene glycol mono-n-pentyl ether, Propylene glycol mono-iso-pentyl ether, propylene glycol mononeopentyl ether, propylene glycol mono-n-hexyl ether, propylene glycol mono-iso-hexyl ether, dipropylene glycol mono-n-butyl ether, dipropylene glycol mono-n- Propyl ether, dipropylene glycol mono-iso-propyl ether, dipropylene glycol mono-n-pe Nyl ether, dipropylene glycol mono-iso-pentyl ether, dipropylene glycol mono neopentyl ether, dipropylene glycol mono-n-hexyl ether, dipropylene glycol mono-iso-hexyl ether, tripropylene glycol mono-n-pentyl ether Tripropylene glycol mono-iso-pentyl ether, tripropylene glycol mononeopentyl ether, tripropylene glycol mono-n-hexyl ether, tripropylene glycol mono-iso-hexyl ether, tetraethylene glycol mono-2-ethylhexyl ether, etc. Can be mentioned.

  Examples of monohydric alcohols include methanol, ethanol, n-propyl alcohol, iso-propyl alcohol, 2,2-dimethyl-1-propanol, n-butanol, 2-butanol, tert-butanol, iso-butanol, 2 -Water-soluble ones such as methyl-1-butanol, 3-methyl-1-butanol, 3-methyl-2-butanol, n-pentanol, 2-pentanol, 3-pentanol, tert-pentanol It is done.

  The amount of the penetrating solvent described above is preferably in the range of 10% by weight or less, more preferably 8% by weight or less, based on the total amount of the aqueous ink composition. By adding in this range, it is possible to provide a water-based ink composition having improved wettability to the film.

(Humectant)
The aqueous ink composition according to the present invention preferably further contains a humectant as necessary. This humectant has an action of preventing the aggregation and precipitation of solids such as pigments and thermoplastic resins in the ink by suppressing the evaporation of water in the aqueous ink composition. Further, when printing the water-based ink composition by the ink jet recording method, it also has an action of preventing clogging, ejection failure and the like by suppressing drying and solidification of the ink on the nozzle surface of the ink jet head. Examples of the humectant having such an action include polyhydric alcohols and nitrogen-containing compounds.

  Examples of polyhydric alcohols include glycerin, ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, polypropylene glycol, 1,3-propanediol, 1,4-butanediol. 1,5-pentanediol, 2,3-butanediol, 2-methyl-2,4-pentanediol, 2-ethyl-1,3-hexanediol, 1,2,6-hexanetriol, pentaerythritol, 1 , 6-hexanediol, 1,8-octanediol, 2,2-dimethyl-1,3-propanediol, 2,2-diethyl-1,3-propanediol, trimethylolethane, trimethylolpropane and the like. .

  Examples of nitrogen-containing compounds include urea, 2-imidazolidinone, thiourea, and 1,3-dimethyl-2-imidazolidinone.

  The amount of these humectants to be added is preferably 20% by weight or less, more preferably 10% by weight or less, based on the total amount of the water-based ink composition. By adding in this range, the water-based ink composition according to the present invention can be further provided with clogging prevention properties and ejection stability. On the other hand, if it is added in excess of this range, the drying of the ink becomes too slow, and the formation of a film of the thermoplastic resin may be hindered. May peel off.

(Other additive components)
In addition to the materials described above, a pH adjuster, antiseptic / antifungal agent, rust inhibitor, chelating agent, and the like can be added to the water-based ink composition according to the present invention as necessary.

  Examples of pH adjusters include potassium dihydrogen phosphate, disodium hydrogen phosphate, sodium hydroxide, lithium hydroxide, potassium hydroxide, ammonia, diethanolamine, triethanolamine, triisopropanolamine, potassium carbonate, sodium carbonate, carbonate Sodium hydrogen etc. are mentioned.

  Examples of the antiseptic / antifungal agent include sodium benzoate, sodium pentachlorophenol, sodium 2-pyridinethiol-1-oxide, sodium sorbate, sodium dehydroacetate, 1,2-dibenzisothiazolin-3-one, etc. Or, as a commercially available product, Proxel XL2, Proxel GXL (above trade name, manufactured by Avisia), Denside CSA, NS-500W (above trade name, manufactured by Nagase ChemteX Corporation) and the like can be mentioned.

  Examples of the rust preventive include benzotriazole.

  Examples of the chelating agent include ethylenediaminetetraacetic acid and salts thereof (ethylenediaminetetraacetic acid dihydrogen disodium salt and the like).

(Physical properties of water-based ink composition, etc.)
The water-based ink composition according to the present invention can prevent corrosion when a metal part is used in the flow path of the water-based ink composition in the apparatus in the viewpoint of ensuring storage stability and dispersion stability, and in the ink jet recording method. From this point, it is desirable that the pH is adjusted to be neutral or alkaline. More desirably, the pH of the aqueous ink composition at 25 ° C. is in the range of 7.0 to 10.0. Deviating from this range tends to cause problems in terms of storage stability, dispersion stability, and corrosion. The pH can be adjusted to a desired range with the pH adjusting agent described above.

  In addition, the water-based ink composition according to the present invention preferably has a viscosity of 25 cPs or less at 25 ° C. from the viewpoint of ensuring ejection stability in the ink jet recording method. More preferably, it is 15 cPs or less.

  Further, the water-based ink composition according to the present invention has a surface tension at 25 ° C. of 20 mN / m to 40 mN / m from the viewpoint of securing ejection stability in the ink jet recording method and securing wettability on a plastic film. The range of 25 mN / m to 35 mN / m is more preferable.

(Method for producing aqueous ink composition)
The water-based ink composition according to the present invention can be obtained by mixing the above-described materials in an arbitrary order and removing impurities by filtering or the like as necessary. Here, the pigment and the thermoplastic resin are preferably prepared in advance in a dispersion state and then mixed from the viewpoint of ease of handling and the like.

  As a method for mixing the respective materials, a method in which the materials are sequentially added to a container equipped with a stirring device such as a mechanical stirrer or a magnetic stirrer and stirred and mixed is preferably used. As a filtration method, centrifugal filtration, filter filtration, or the like can be performed as necessary.

(Recorded material)
The recorded matter of the present invention can be obtained by printing on a plastic film or the like using the above-described ink jet recording method and aqueous ink composition. According to this method, a recorded image with a clear image with less unevenness of density and blur and excellent fixability can be obtained.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited by these Examples. “Parts” shown below means “parts by weight” unless otherwise specified.

[Production of water-based ink composition]
(Manufacture of pigment dispersion)
A resin-dispersed pigment in which a pigment was dispersed with a resin dispersant was used as a colorant to be provided to the water-based ink compositions of Examples and Comparative Examples. When added to the water-based ink composition, a pigment dispersion in which the resin-dispersed pigment was dispersed in water was used. Therefore, prior to the evaluation shown below, a pigment dispersion to be used was produced. As for the pigment dispersion, Joncryl 67 (trade name, weight average molecular weight: 12,500, acid value: 213, manufactured by BASF Japan Ltd.): 4.5 parts as a resin dispersant: 30% ammonia as a neutralizing agent Aqueous solution: 1 part dissolved ion-exchanged water: added to 79.5 parts and dissolved, then added the following pigment: 15 parts, dispersed in a ball mill with zirconia beads for 10 hours, and then by a centrifuge Centrifugal filtration was performed to remove impurities such as coarse particles and dust, and the pigment concentration was 15% by weight. Below, the pigment kind used for manufacture of a pigment dispersion liquid is shown.
C. I. Pigment Black 7 (used for black pigment dispersion)
C. I. Pigment Yellow 74 (used for yellow pigment dispersion)
C. I. Pigment Red 122 (used for magenta pigment dispersion)
C. I. Pigment Blue 15: 3 (used for cyan pigment dispersion)
C. I. Pigment Orange 43 (used for orange pigment dispersion)
C. I. Pigment Green 36 (used for green pigment dispersion)

(Production of water-based ink composition)
Ink set composition example 1 to ink set composition example comprising six colors of black, yellow, magenta, cyan, orange and green with the material composition shown in Table 1 using the pigment dispersion prepared by the above materials and methods. Ten aqueous ink compositions were produced. For each water-based ink composition, the materials shown in Table 1 are placed in a container, mixed with stirring with a magnetic stirrer for 2 hours, and then filtered with a membrane filter having a pore size of 5 μm to remove impurities such as dust and coarse particles. It was manufactured by. In addition, all the numerical values in Table 1 show weight%.

ここで、各水性インク組成物に使用したシロキサン系界面活性剤はＢＹＫ−３４８（商品名、ビックケミー・ジャパン株式会社製）、ジアセチレンテトラオールはサーフィノールＭＤ−２０（商品名、Ａｉｒ Ｐｒｏｄｕｃｔｓ ａｎｄ Ｃｈｅｍｉｃａｌｓ Ｉｎｃ．製）、熱可塑性樹脂はジョンクリル５３７Ｊ（商品名、スチレン−アクリル系樹脂エマルジョン、酸価：４０、Ｔｇ：４９℃、ＢＡＳＦジャパン株式会社製）である。

Here, the siloxane surfactant used in each water-based ink composition is BYK-348 (trade name, manufactured by Big Chemie Japan Co., Ltd.), and diacetylenetetraol is Surfynol MD-20 (trade name, Air Products and Chemicals). Inc.), a thermoplastic resin is Jonkrill 537J (trade name, styrene-acrylic resin emulsion, acid value: 40, Tg: 49 ° C., manufactured by BASF Japan Ltd.).

[Printing evaluation]
(Evaluation of bleeding of recorded matter)
A recording medium whose recording surface is a polyethylene terephthalate film (trade name: Cold Laminated Film PG-50L, manufactured by Lamy Corporation) was used. Ink jet printer PX-G900 (trade name, manufactured by Seiko Epson Corporation) was filled with inks of ink set composition examples 1 to 10 shown in Table 1. Then, when the recording medium is set in the sheet feeder section and the recording medium is heated to 70 ° C. with a dryer and the recording medium is 45 ° C. during printing, the recording medium is printed with a dryer. Printing was performed at two levels, that is, when the recording medium was printed at 35 ° C. by heating to 50 ° C. When printing, a pattern that can be printed in 10% increments with a duty in the range of 40% to 100% was created and used because the two colors were in contact with each other at a resolution of 1,440 dpi in the horizontal direction and 1,440 dpi in the vertical direction. The blur of the recorded material when printed under the above conditions was visually confirmed. The judgment criteria were as follows. Table 2 shows the evaluation results when the recording medium is 45 ° C. during printing, and Table 3 shows the case where the recording medium is 35 ° C. during printing.
Judgment criteria;
A: No bleeding is observed even when the duty is 60% or more.
B: No bleeding is observed up to a duty of 50%.
C: No bleeding is observed up to 40% duty.
D: Bleeding is observed even at a duty of 40%.
Here, when the duty is 1,440 dpi in the horizontal direction and 1,440 dpi in the vertical direction, the ink dots are arranged in what percentage of the total of 2,073,600 divisions obtained by dividing one square inch into 1,440 horizontal divisions and 1,440 vertical divisions. Indicates whether it has been placed. That is, in the case of 40% duty, it indicates that ink dots are arranged in the 829,440 divided portions.

(Evaluation of uneven density of recorded material)
A recording medium whose recording surface is a polyethylene terephthalate film (trade name: Cold Laminated Film PG-50L, manufactured by Lamy Corporation) was used. Ink jet printer PX-G900 (trade name, manufactured by Seiko Epson Corporation) was filled with inks of ink set composition examples 1 to 10 shown in Table 1. Then, when the recording medium is set in the sheet feeder section and the recording medium is heated to 70 ° C. with a dryer and the recording medium is 45 ° C. during printing, the recording medium is printed with a dryer. Printing was performed at two levels, that is, when the recording medium was printed at 35 ° C. by heating to 50 ° C. In printing, a monochrome fill pattern that can be printed in 10% increments with a resolution of 1,440 dpi in width and 1,440 dpi in height and a duty in the range of 40% to 100% was used. The density unevenness of the recorded material when printed under the above conditions was visually confirmed. The judgment criteria were as follows. Table 2 shows the evaluation results when the recording medium is 45 ° C. during printing, and Table 3 shows the case where the recording medium is 35 ° C. during printing.
Judgment criteria;
A: Even if the duty is 70% or more, uneven density is not recognized.
B: No shading unevenness is observed up to a duty of 60%.
C: No shading unevenness is observed up to a duty of 50%.
D: Density unevenness is observed even at a duty of 50%.

(Discharge stability evaluation)
A recording medium whose recording surface is a polyethylene terephthalate film (trade name: Cold Laminated Film PG-50L, manufactured by Lamy Corporation) was used. Ink jet printer PX-G900 (trade name, manufactured by Seiko Epson Corporation) was filled with inks of ink set composition examples 1 to 10 shown in Table 1. Then, when the recording medium is set in the sheet feeder section and the recording medium is heated to 70 ° C. with a dryer and the recording medium is 45 ° C. during printing, the recording medium is printed with a dryer. Printing was performed at two levels, that is, when the recording medium was printed at 35 ° C. by heating to 50 ° C. At the time of printing, a 100% duty single-color fill pattern with a resolution of 1,440 dpi in the horizontal direction and 1,440 dpi in the vertical direction was used so that each color was printed evenly in the A4 size. Ejection stability was evaluated by printing 200 sheets of A4 size paper under the above conditions, and visually confirming that the obtained recorded matter was missing or bent. The judgment criteria were as follows. Table 2 shows the evaluation results when the recording medium is 45 ° C. during printing, and Table 3 shows the case where the recording medium is 35 ° C. during printing.
Judgment criteria;
A: Even after printing 200 sheets, all the ink is removed and no flying curve is recognized.
B: Up to 100 sheets of printing, all the ink is removed and no flying curve is recognized.
C: There are inks with missing and less than 10 flying bends by printing 100 sheets.
D: There are inks with missing and flying bends at 10 or more places by printing 100 sheets.

  As shown in Tables 2 and 3, using the ink sets of Ink Set Composition Example 1 to Ink Set Composition Example 6, the recorded matter when the print medium was printed at 45 ° C. during printing was The shading unevenness was also good, and there was no problem in ejection stability.

  On the other hand, when the recording medium was printed at 35 ° C. during printing, bleeding and shading unevenness occurred in the recorded matter. In addition, as an ink composition, a siloxane-based surfactant is in a range of 0.1 wt% to 1.5 wt%, and a diacetylene tetraol represented by the following formula (1) is 0.01 wt% to 1 wt%. Ink set composition example 7 to ink set composition example 10 that are out of the range, even if the recording medium is set to 45 ° C. during printing, bleeding and shading unevenness occurs in the recorded matter, and the ejection stability is also inferior. It was.

  As described above, in the ink jet recording method according to the present invention, even when printing is performed on a recording medium whose recording surface is a plastic film (that is, non-coated plastic media, etc.), there are few unevenness of ink density, bleeding, color mixing, etc. Excellent discharge stability.

Claims (9)

An ink jet recording method for performing printing by discharging droplets of a water-based ink composition onto a recording medium having a recording surface made of a plastic film and attaching the droplets to the recording surface,
Examples of the water-based ink composition include a colorant, 0.1% by weight to 1.5% by weight of a silicon-based surfactant, and 0.01% by weight to 1% by weight of diacetylenetetraol represented by the following formula (1). A water-based ink composition containing at least a pyrrolidone derivative, a thermoplastic resin, and water,
An inkjet recording method comprising a step of heating the water-based ink composition adhered to a recording surface to 40 ° C. or more.

  2. The ink jet recording method according to claim 1, wherein the silicon surfactant is a polysiloxane compound, and the pyrrolidone derivative is N-methyl-2-pyrrolidone.   3. The ink jet recording method according to claim 1, wherein an addition amount of the pyrrolidone derivative in the water-based ink composition is 2.0 wt% to 25.0 wt%.   The inkjet recording method according to claim 1, wherein the colorant is a pigment, and the pigment is dispersed in an aqueous ink composition.   The inkjet recording method according to claim 1, wherein the water-based ink composition further comprises a penetrating solvent.   6. The ink jet recording method according to claim 5, wherein the penetrating solvent is selected from at least one selected from the group consisting of 1,2-alkyldiols, glycol ethers, and monohydric alcohols.   The inkjet recording method according to any one of claims 1 to 6, wherein the water-based ink composition further comprises a humectant.   The ink jet recording method according to claim 1, wherein the heat treatment is performed by heater heating or hot air drying.   A recorded matter, wherein an image is formed using the ink jet recording method according to any one of claims 1 to 8.