JP2012224044A - Inkjet recording method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inkjet recording method that can form, by using an aqueous ink composition, an image with superior abrasion resistance to various kinds of recording medium, especially recording medium that has no absorbability or low absorbability for ink, and also can form an image with superior print quality and abrasion resistance.SOLUTION: The inkjet recording method includes steps for: heating a recording surface of the recording medium having no absorbability or low absorbability for ink, up to a temperature of 40-110°C; and performing recording on the recording medium by using an aqueous ink composition containing paraffin wax having a melting point of 110°C or lower, and at least one kind of a non-aqueous colorant, and water.

Description

  The present invention relates to an ink jet recording method using an aqueous ink composition on a non-ink-absorbing or low-absorbing recording medium.

  A printing method using an ink jet recording method is performed by causing ink droplets to fly and adhere to a recording medium such as paper. Due to recent advances in ink-jet recording technology, printing methods using ink-jet recording are now being used in the field of high-definition image recording (image printing), which previously used photographs and offset printing. It has become. For this reason, high-quality printed materials can be found not only on commonly used plain paper and special paper for inkjet recording (matte and glossy) but also on non-ink-absorbing or low-absorbing recording media such as printing paper, synthetic paper, and films. It has been demanded.

  In recent years, instead of solvent-based pigment inks that have been used for film-based recording media such as polyvinyl chloride-based substrates, that is, non-ink-absorbing recording media, a viewpoint that protects safety and the environment. Accordingly, water-based inks have been used. Specific examples of such water-based inks include water, glycol solvents, insoluble colorants, polymer dispersants, silicone surfactants, fluorinated surfactants, water-insoluble graft copolymer binders, and N-methylpyrrolidone. There has been proposed a method of printing on a hydrophobic surface using the contained ink (see Patent Document 1). In addition, aqueous colloid-containing aqueous inkjet inks have been proposed for printing on non-porous substrates consisting of an aqueous liquid vehicle containing a volatile cosolvent having a boiling point of 285 ° C. or lower, acid functionalized polymer colloid particles, and a pigment colorant. (See Patent Document 2). In addition, a heat-fixable ink in which spots are prevented using an organic solvent having a specific solubility parameter has been proposed (see Patent Document 3).

  However, the conventionally proposed water-based inks cannot be said to be sufficiently excellent in the print quality and abrasion resistance of images formed on a recording medium, and an ink composition with improved properties is required. It was. Specifically, color mixing between different colors or a phenomenon that spreads beyond the desired area (hereinafter referred to as “bleed”) occurs, or the ink is dark and light in the filled image. The conventional ink composition has not been able to obtain a desired print quality due to the phenomenon (hereinafter referred to as “shading unevenness”). In addition, in the printed matter of the conventional ink composition, the printed surface is frequently scraped or peeled off from the recording medium when the item hits and rubs, so that practical rub resistance is required. In addition, among non-ink-absorbing or low-absorbing recording media, ink recorded on a recording medium made of a material such as polypropylene or polyethylene terephthalate is more easily peeled off from the recording medium, and the abrasion resistance of these materials is reduced. There was a further need for improvement.

JP 2000-44858 A JP 2005-220352 A JP 2008-260820 A

  The present invention provides an ink jet recording method capable of forming an image having excellent abrasion resistance on various recording media, in particular, non-ink-absorbing or low-absorbing recording media, using an aqueous ink composition. It is another object of the present invention to provide an inkjet recording method capable of forming an image having excellent print quality and abrasion resistance.

The above object is achieved by the following invention.
(1) The surface temperature of the recording side of a non-ink-absorbing or low-absorbing recording medium is heated to a range of 40 ° C. or higher and 110 ° C. or lower, paraffin wax having a melting point of 110 ° C. or lower, and at least one water-insoluble type. An ink jet recording method comprising: recording using a water-based ink composition containing the above colorant and water.
(2) a first step in which the surface temperature of the recording medium on the recording side is heated to a range of 40 ° C. or higher and 80 ° C. or lower to discharge aqueous ink, and the recording medium is heated to 50 ° C. or higher and 110 ° C. or lower The inkjet recording method according to (1), further comprising a second step of drying the ink.
(3) The inkjet recording method according to (1) or (2), wherein the water-based ink composition further contains a polyethylene wax.
(4) The inkjet recording method according to any one of (1) to (3), wherein the water-based ink composition does not substantially contain an alkyl polyol having a boiling point under 1 atm of 280 ° C. or higher.
(5) The inkjet recording method according to any one of (1) to (4), wherein the water-based ink composition contains the paraffin wax in an amount of 0.1% by mass to 3% by mass.
(6) The water-based ink composition further comprises 1,2-alkyldiol having 5 to 7 carbon atoms, resin particles, a nonionic surfactant, and a pyrrolidone derivative. 5) The inkjet recording method according to any one of the above.
(7) The inkjet recording method according to any one of (1) to (6), wherein the paraffin wax has an average particle size of 5 nm to 400 nm.
(8) A recorded matter recorded by the inkjet recording method according to any one of (1) to (7).

  According to the ink jet recording method of the present invention, it is possible to form an image having excellent abrasion resistance and printing quality with respect to a non-ink-absorbing or low-absorbing recording medium.

Hereinafter, preferred embodiments of the present invention will be described in detail.
In addition, all the average particle diameters described in this specification are “volume-based average particle diameters”.

1. Aqueous Ink Composition The aqueous ink composition in the present invention contains at least a water-insoluble colorant, a paraffin wax having a melting point of 110 ° C. or less, and water.
The water-based ink composition in the present invention is preferably a component other than the above components, preferably 1,2-alkyldiol having a carbon number of 5 to 7, resin particles, nonionic surfactant, pyrrolidone derivative, polyethylene wax, etc. including.
Hereinafter, these constituent materials will be described in detail.

1.1 Colorant The water-based ink composition in the invention contains a water-insoluble colorant.
Examples of the water-insoluble colorant include water-insoluble dyes or pigments. Pigments are preferable, and it is desirable that the water-insoluble colorant be dispersed in the ink with a water-soluble resin. The pigment is not only insoluble or hardly soluble in water but also has a property of hardly fading to light, gas, and the like. For this reason, a printed matter printed with an ink composition using a pigment is excellent in water resistance, gas resistance, light resistance, and the like, and has good storage stability.
As the pigment, any of known inorganic pigments, organic pigments, and carbon black can be used. Among these, carbon black and organic pigments are preferred from the viewpoints of good color development and low sedimentation, which makes it difficult to settle during dispersion.

Preferable specific examples of 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). Note that these are examples of carbon black suitable for the present invention, and the present invention is not limited to these.
These carbon blacks may be used alone or as a mixture of two or more. The content of these carbon blacks is 0.1% by mass to 20% by mass, preferably 0.5% by mass to 10% by mass with respect to the total amount of the black ink composition.

Preferred organic pigments are quinacridone pigments, quinacridone quinone pigments, dioxazine pigments, phthalocyanine pigments, anthrapyrimidine pigments, anthanthrone pigments, indanthrone pigments, flavanthrone pigments, perylene pigments, diketo Examples thereof include pyrrolopyrrole 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, 15: 1, 15: 2, 15: 3, 15: 4, 15: 6, 15:34, 16, 18, 22, 25, 60, 65, 66, C.I. I. Bat blue 4, 60 and the like, preferably C.I. I. It is a single or a mixture of two or more selected from the group consisting of CI Pigment Blue 15: 3 and 15: 4. The content of these pigments is about 0.1% by mass to 20% by mass, preferably about 0.5% by mass to 10% by mass with respect to the total amount of the cyan ink composition.

  Examples of the pigment used in the magenta ink composition include C.I. I. Pigment Red 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 14, 15, 16, 17, 18, 19, 21, 22, 23, 30, 31, 32, 37, 38, 40, 41, 42, 48 (Ca), 48 (Mn), 57 (Ca), 57: 1, 88, 112, 114, 122, 123, 144, 146, 149, 150, 166, 168 170, 171, 175, 176, 177, 178, 179, 184, 185, 187, 202, 209, 219, 224, 245, 254, 264 or C.I. I. Pigment violet 19, 23, 32, 33, 36, 38, 43, 50 and the like. Preferably, it is a single or a mixture of two or more selected from the group consisting of red 122, red 202 and violet 19. The content of these pigments is about 0.1% by mass to 20% by mass, preferably about 0.5% by mass to 10% by mass with respect to 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, 4, 5, 6, 7, 10, 11, 12, 13, 14, 16, 17, 24, 34, 35, 37, 53, 55, 65, 73, 74, 75, 81, 83, 93, 94, 95, 97, 98, 99, 108, 109, 110, 113, 114, 117, 120, 124, 128, 129, 133, 138, 139, 147, 151, 153, 154, 155, 167, 172, 180, 185, 213 and the like. Preferably, it is a single or a mixture of two or more selected from the group consisting of 74, 155 and 213. The content of these pigments is about 0.1% by mass to 20% by mass, preferably about 0.5% by mass to 10% by mass with respect to the total amount of the yellow ink composition.

In order to apply the above pigment to an aqueous ink composition, it is necessary to enable the pigment to be stably dispersed and held in water.
As the method, a method of dispersing with a resin dispersant such as a water-soluble resin and / or a water-dispersible resin (hereinafter, a pigment treated by this method is referred to as a “resin-dispersed pigment”), a water-soluble surfactant A method of dispersing with a surfactant of an agent and / or a water-dispersible surfactant (hereinafter, a pigment treated by this method is referred to as “surfactant-dispersed pigment”), and hydrophilic functional groups on the surface of pigment particles In which the pigment treated by this method can be dispersed and / or dissolved in water without a dispersant such as the above-mentioned resin or surfactant (hereinafter referred to as “surface-treated pigment”). And the like).
As the water-based ink composition used in the printing method according to the present embodiment, any of the above resin-dispersed pigments, surfactant-dispersed pigments, and surface-treated pigments can be used. It can also be used. In particular, the resin-dispersed pigment is preferable because when the water-based ink recording material adheres to the recording medium, the adhesion between the recording medium and the ink composition and / or the solidified material in the ink composition may be improved. Further, the surface-treated pigment is preferable from the viewpoint of improving the dispersion stability of the pigment and improving the storage stability of the aqueous ink composition.

Examples of the resin dispersant used for the resin dispersion pigment include polyvinyl alcohols, polyacrylic acid, acrylic acid-acrylonitrile copolymer, vinyl acetate-acrylic acid ester copolymer, acrylic acid-acrylic acid ester copolymer, and 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- Acrylate ester copolymer, styrene-maleic acid copolymer, styrene-maleic anhydride copolymer, vinyl naphthalene-acrylic acid copolymer, vinyl naphthalene-maleic acid copolymer, vinyl acetate-maleic acid ester copolymer Polymer, vinyl acetate-crotonic acid copolymer, vinyl acetate-acrylic Examples include acid copolymers 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 basic compounds such as ammonia, ethylamine, diethylamine, triethylamine, propylamine, isopropylamine, dipropylamine, butylamine, isobutylamine, diethanolamine, triethanolamine, triisopropanolamine, aminomethylpropanol, and morpholine. Of the salt.
The addition amount of these basic compounds 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 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, a stable dispersion of the colorant in water can be obtained, and viscosity control when applied to an 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 colorant particles in water can be stably secured, and the water resistance of the printed matter printed with the aqueous ink composition using the colorant particles 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, and dialkyl sulfo oxalate. 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, monoglycerite phosphate ester salts, Amphoteric surfactants such as alkyl pyridium salts, alkyl amino acid salts, alkyl dimethyl betaines, polyoxyethylene alkyl ethers, polyoxyethylene alkyl phenyl ethers, polyoxyethylene alkyl esters, polyoxyethylenes Alkylamide, glycerol alkyl esters, nonionic surfactants such as sorbitan alkyl esters.

  The amount of the resin dispersant or the surfactant added to the pigment is preferably 1 part by mass to 100 parts by mass, more preferably 5 parts by mass to 50 parts by mass with respect to 100 parts by mass of the pigment. By being in this range, the dispersion stability of the pigment in water can be ensured.

As the surface-treated pigment, as the 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 (wherein M represents a hydrogen atom, an alkali metal, ammonium, or organic ammonium, and R represents an alkyl group having 1 to 12 carbon atoms or a substituent. An optionally substituted phenyl group or an optionally substituted naphthyl group.) And the like.
These functional groups are physically and / or chemically introduced by grafting directly to the pigment particle surface and / or via multivalent 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 chemically bond, that is, the pigment does not have an active proton, has no reactivity with sulfonic acid, and the pigment is insoluble or hardly soluble. In the solvent, the pigment is dispersed, 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.

  As a method for dispersing the above-described resin dispersed pigment, surfactant dispersed pigment, and surface-treated pigment in water, the pigment-dispersed pigment, water, and resin dispersant for the resin-dispersed pigment, and the pigment, water, and interface for the surfactant-dispersed pigment For activators and surface-treated pigments, add surface-treated pigment and water, and water-soluble organic solvents / neutralizers, etc., if necessary. Ball mill, sand mill, attritor, roll mill, agitator mill, Henschel mixer, colloid It can be carried out by a conventionally used disperser such as a mill, 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, and more preferably in the range of 50 nm to 200 nm. This is preferable. Further, by using a pigment having an average particle diameter of 250 nm or less, clogging can be suppressed, and more sufficient ejection stability can be realized.

1.2 Paraffin Wax The aqueous ink composition according to the invention contains paraffin wax. By including paraffin wax in the water-based ink composition, slip properties are imparted to the recorded matter, thereby improving the abrasion resistance. Moreover, since paraffin wax has water repellency, the water resistance of recorded matter can be improved if the amount is appropriate. Furthermore, an ink composition in which clogging is well prevented is obtained. Paraffin wax is a so-called petroleum-based wax, which is a hydrocarbon having a molecular weight of about 300 to 500, mainly composed of straight-chain paraffinic hydrocarbons (normal paraffins) having 20 to 30 carbon atoms and a small amount of iso-paraffins. A mixture of
In the aqueous ink composition of the present invention, the paraffin wax is preferably contained in a fine particle state (that is, an emulsion state or a suspension state). By containing the paraffin wax in a fine particle state, it is easy to adjust the viscosity of the aqueous ink composition to an appropriate range in the ink jet recording method, and it is easy to ensure storage stability and ejection stability. The melting point of the paraffin wax is not particularly limited, but is preferably 110 ° C. or lower. If the melting point of the paraffin wax exceeds 110 ° C., the film of the recorded matter may be fragile. On the other hand, the melting point of paraffin wax is preferably 60 ° C. or higher. This is because if the temperature is less than 60 ° C., the recording surface may become sticky without drying. More preferably, the melting point of the paraffin wax is 70 ° C. or higher and 95 ° C. or lower. By being in this range, the ejection stability becomes good.

When the paraffin wax is 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. It is a range. As the paraffin wax, commercially available products can be used as they are, and examples thereof include AQUACER 537 and AQUACER 539 (trade names, manufactured by Big Chemie Japan Co., Ltd.).
The paraffin wax is preferably contained in the range of 0.1 to 3% by mass in terms of solid content, and preferably in the range of 0.1 to 1.5% by mass, based on the total amount in the aqueous ink composition. More preferably. Since the content of the paraffin wax is included in the above range, on the non-ink-absorbing or low-absorbing recording medium, the print quality such as blocking resistance and water resistance can be obtained only by rubbing the image. It is possible to form an excellent image.

1.3 Water
The water-based ink composition in the invention contains water.
Water is a main medium of the water-based ink composition, and is a component that evaporates and scatters in a second step (drying step) described later. The water is preferably water from which ionic impurities such as pure water such as ion exchange water, ultrafiltration water, reverse osmosis water, distilled water or ultrapure water are removed as much as possible. Use of water sterilized by ultraviolet irradiation or addition of hydrogen peroxide is preferable because it can prevent the generation of mold and bacteria when the pigment dispersion and the aqueous ink composition using the same are stored for a long period of time. is there.

1.4 Other components
1.4.1 1,2-alkyldiols having 5 to 7 carbon atoms The water-based ink composition of the present invention has 5 to 7 carbon atoms (hereinafter sometimes abbreviated as C5 to 7). It is desirable to include 1,2-alkyldiols in the range of
C5-7 1,2-alkyldiols have the effect of further increasing the wettability of the water-based ink composition with respect to the recording medium to uniformly wet it, and the effect of further increasing the permeability. Therefore, by adding C5-7 1,2-alkyldiols to the water-based ink composition, it is possible to further reduce ink density unevenness and bleeding.

  Specific examples of C5-7 1,2-alkyldiols include 1,2-pentanediol, 1,2-hexanediol, 1,2-heptanediol, and 4-methyl-1,2-pentanediol. Etc.

  The addition amount of C5-7 1,2-alkyldiols is preferably 0.5% by mass to 20% with respect to the total amount of the aqueous ink composition from the viewpoint of ensuring the storage stability and ejection stability of the aqueous ink composition. It is the range of mass%, More preferably, it is the range of 1 mass%-8 mass%. If the content of C5-7 1,2-alkyldiols is less than 0.5% by mass, the wetness of the water-based ink composition with respect to the recording medium will be poor, resulting in density unevenness and blurring on the printed matter. There is a case. On the other hand, when the content is more than 20% by mass, it is difficult to keep the viscosity of the water-based ink composition within an appropriate range in the ink jet recording method, and the ejection becomes unstable, and the storage stability of the water-based ink composition is ensured over a long period of time. May be difficult.

1.4.2 Resin Particles The aqueous ink composition in the present invention preferably contains resin particles.
By including resin particles in the water-based ink composition, an image having better abrasion resistance can be formed on the recording medium. In particular, when printing using a water-based ink composition containing the resin particles on a non-ink-absorbing or low-ink-absorbing recording medium such as polypropylene film and polyethylene terephthalate, the ink jet recording method of the present invention will be described later. By passing through the 2nd process (drying process) to perform, the image which is further excellent in abrasion resistance is obtained. The resin particles are preferably thermoplastic.
The reason is that in the second step (drying step) to be described later of the ink jet recording method of the present invention, the resin particles have a function of solidifying the ink and further fixing the solidified ink on the recording medium. Yes, this effect can be further enhanced by heating.
In particular, in the water-based ink composition of the present invention, the resin particles are preferably contained in a fine particle state (that is, an emulsion state or a suspension state). By containing the resin particles in a fine particle state, it is easy to adjust the viscosity of the water-based ink composition to an appropriate range in the ink jet recording method, and it is easy to ensure storage stability and ejection stability.

Hereinafter, the resin particles will be described in detail.
Examples of the resin particle component include acrylic acid, acrylic ester, methacrylic acid, methacrylic ester, acrylonitrile, cyanoacrylate, acrylamide, olefin, styrene, vinyl acetate, vinyl chloride, vinyl alcohol, vinyl ether, vinyl pyrrolidone, vinyl pyridine. , Vinyl carbazole, vinyl imidazole, vinylidene chloride homopolymer or copolymer, fluororesin, natural resin and the like. The copolymer can be used in any form of a random copolymer, a block copolymer, an alternating copolymer, and a graft copolymer. The resin particles are preferably acrylic resins or styrene-acrylic acid copolymer resins.

  As the resin particles as described above, those obtained by known materials and methods can be used. 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.

Said resin particle is obtained by the method shown below, Any method may be sufficient and it may combine a some method as needed. As the method, a polymerization catalyst (polymerization initiator) and a dispersing agent are mixed in a monomer of a component constituting a desired resin particle and polymerized (that is, emulsion polymerization), or a resin particle having a hydrophilic portion. A method of obtaining particles by dissolving water in a water-soluble organic solvent, mixing the solution in water, and removing the water-soluble organic solvent by distillation or the like, dissolving resin particles in a water-insoluble organic solvent and mixing the solution with a dispersant Examples thereof include a method of obtaining particles by mixing in an aqueous solution. Said method can be suitably selected according to the kind and characteristic of the resin particle to be used.
The dispersant that can be used when dispersing the resin particles in a fine particle state is not particularly limited, but anionic surfactants (for example, sodium dodecylbenzenesulfonate, sodium lauryl phosphate, polyoxyethylene alkyl) Ether sulfate ammonium salts), nonionic surfactants (for example, polyoxyethylene alkyl ether, polyoxyethylene alkyl ester, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene alkylphenyl ether, etc.) These can be used alone or in admixture of two or more.

  The average particle diameter of the resin particles is preferably in the range of 5 nm to 400 nm, more preferably in the range of 20 nm to 300 nm, from the viewpoint of ensuring the storage stability and ejection stability of the aqueous ink composition.

  The content of the resin particles is preferably 15% by mass or less, more preferably 0.2% by mass to 10% by mass in terms of solid content with respect to the total amount of the aqueous ink composition. By being within this range, the aqueous ink composition can be solidified and fixed even on a non-ink-absorbing or low-absorbing recording medium. When the content exceeds 15% by mass, the storage stability and ejection stability of the water-based ink composition may not be ensured.

1.4.3 Waxes other than paraffin wax The aqueous ink composition in the invention preferably contains a wax other than the paraffin wax. Like the paraffin wax, the wax has a function of imparting slip property to the surface of the formed printed matter and improving abrasion resistance. The wax other than the paraffin wax is preferably contained in the aqueous ink composition in a fine particle state (that is, an emulsion state or a suspension state). By containing in a fine particle state, it is easy to adjust the viscosity of the water-based ink composition to an appropriate range in the ink jet recording method, and it is easy to ensure storage stability and ejection stability.

Examples of the components constituting the wax include plant and animal waxes such as carnauba wax, candeli wax, beeswax, rice wax, and lanolin; petroleum waxes such as microcrystalline wax, polyethylene wax, polyethylene oxide wax, and petrolatum; Mineral waxes such as montan wax and ozokerite; synthetic waxes such as carbon wax, Hoechst wax, polyolefin wax, stearamide, natural / synthetic wax emulsions such as α-olefin / maleic anhydride copolymer and blended wax These can be used alone or in combination. Among these waxes, polyolefin wax is preferable, polyethylene wax and polypropylene wax are more preferable, and polyethylene wax is most preferable.
As the wax, commercially available products can be used as they are, for example, Nopcoat PEM17 (trade name, manufactured by San Nopco), Chemipearl W4005 (trade name, manufactured by Mitsui Chemicals), AQUACER 515, AQUACER 593 (above, trade names, Big Chemie Japan). Etc.).
The average particle size of the wax other than the paraffin wax 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.

  The content of the wax other than the paraffin wax is preferably 5% by mass or less, more preferably in the range of 0.1% by mass to 1% by mass in terms of solid content with respect to the total amount of the aqueous ink composition. By being within this range, a water-based ink composition can be solidified and fixed by combining with a second step (drying step) described later even on a non-ink-absorbing or low-absorbing recording medium. If the content exceeds 5% by mass, the storage stability and ejection stability of the water-based ink composition may not be ensured.

As described above, by containing resin particles in the aqueous ink composition of the present invention, it becomes possible to further improve the abrasion resistance of the printed matter. The reason why the printed material has good abrasion resistance when resin particles and wax are used in combination is not yet clear, but is presumed as follows.
Since the components constituting the resin particles have a good affinity for non-ink-absorbing or low-absorbing recording media and water-insoluble colorants, a resin film is formed in the second step (drying step). At this time, it firmly fixes on the recording medium while wrapping the colorant. On the other hand, the wax component is also present on the surface of the resin film, and has a characteristic of reducing the frictional resistance on the surface of the resin film. This makes it possible to form a resin film that is difficult to be scraped off due to external rubbing and that is difficult to peel off from the recording medium, and it is assumed that the abrasion resistance of the printed matter is improved.

  In the aqueous ink composition of the present invention, the content ratio of the resin particles and the wax is preferably in the range of resin particles: wax = 10: 3 to 10:32 in terms of solid content. If it is within this range, the above-described mechanism works well, and the printed material has good abrasion resistance.

  When the water-based ink composition in the present invention contains polyethylene wax, the mixing ratio of paraffin wax and polyethylene wax is preferably adjusted for each color water-based ink composition. When an aqueous ink composition of multiple colors with different pigment types is configured as an ink set to form an image, if the mixing ratio of paraffin wax and polyethylene wax is the same for each color, the resulting recorded matter will have an abrasion resistance for each color. Therefore, uniform abrasion resistance cannot be obtained over the image forming area. In contrast, by adjusting the content ratio of the polyethylene wax contained in the water-based ink composition for each color, the scratch resistance of the image is made uniform and good scratch resistance is achieved over the entire image forming area. Can be granted.

1.4.4 Nonionic surfactant The aqueous ink composition in the invention preferably contains a nonionic surfactant.
The nonionic surfactant has an action of spreading the aqueous ink composition uniformly on the recording medium.
Therefore, when an aqueous ink composition containing this is used, there is an effect that a clearer image can be obtained with less uneven density and blurring.
Nonionic surfactants having such effects include polyoxyethylene alkyl ethers, polyoxypropylene alkyl ethers, polycyclic phenyl ethers, sorbitan derivatives, fluorines, silicones, acetylene glycols and the like. .
Among these, the silicone-based surfactant is particularly excellent in the above-described effects and has excellent compatibility and synergistic effect with the C5-7 1,2-alkyldiols preferably used in the aqueous ink composition of the present invention. Agents and acetylene glycol surfactants are preferred.

1.4.4.1 Silicone Surfactant The aqueous ink composition in the invention preferably contains a silicone surfactant.
Silicone-based surfactants are superior to other nonionic surfactants in their ability to spread uniformly on the recording medium so as not to cause uneven density or bleeding of ink. In addition, the synergistic effect of compatibility and characteristics with the C5-7 1,2-alkyldiols that can be preferably added to the water-based ink composition of the present invention is excellent.
The content of the silicone surfactant is preferably in the range of 1.5% by mass or less with respect to the total amount of the water-based ink composition. If the content of the silicone surfactant exceeds 1.5% by mass, the storage stability and ejection stability of the water-based ink composition may not be ensured.

As the silicone surfactant, a polysiloxane compound or the like is preferably used, and examples thereof include polyether-modified organosiloxane.
More 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 (above trade names, manufactured by Shin-Etsu Chemical Co., Ltd.) and the like.

1.4.4.2 Acetylene glycol surfactant The aqueous ink composition in the invention preferably contains an acetylene glycol surfactant.
The acetylene glycol-based surfactant is superior to other nonionic surfactants in its ability to keep the surface tension and the interfacial tension properly, and has almost no foaming property. As a result, the aqueous ink composition containing the acetylene glycol surfactant can appropriately maintain the surface tension and the interfacial tension with the printer member in contact with the ink such as the head nozzle surface. When applied to the above, the discharge stability can be improved. Further, since the acetylene glycol surfactant acts as a good wettability / penetrant for the recording medium in the same manner as the C5-7 1,2-alkyldiols, an aqueous ink composition containing the same is used. The printed image by is a high definition with little shading unevenness and blurring. The content of the acetylene glycol surfactant is preferably 1.0% by mass or less based on the total amount of the aqueous ink composition. If the content of the acetylene glycol surfactant exceeds 1.0% by mass, the storage stability and ejection stability of the aqueous ink composition may not be ensured.

  Examples of acetylene glycol surfactants include Surfinol 104, 104E, 104H, 104A, 104BC, 104DPM, 104PA, 104PG-50, 104S, 420, 440, 465, 485, SE, SE-F, 504, 61, DF37, CT111, CT121, CT131, CT136, TG, GA, DF110D (all trade names, manufactured by Air Products and Chemicals, Inc.), Olfin B, Y, P, A, STG, SPC, E1004, E1010, PD -001, PD-002W, PD-003, PD-004, EXP. 4001, EXP. 4036, EXP. 4051, AF-103, AF-104, AK-02, SK-14, AE-3 (all trade names, manufactured by Nissin Chemical Industry Co., Ltd.), acetylenol E00, E00P, E40, E100 (all trade names, Kawaken Fine Chemical Co., Ltd.).

1.4.5 Pyrrolidone Derivative The aqueous ink composition in the invention preferably contains a pyrrolidone derivative.
The pyrrolidone derivative acts as a good solubilizer or softener for the above-described resin particles, thereby promoting film formation by the resin particles when the ink is dried, on a non-ink-absorbing or low-absorbing recording medium. Has the effect of promoting the solidification and fixing of the ink. The content of the pyrrolidone derivative is 5% by mass to 25% by mass with respect to the total amount of the aqueous ink composition. When the content of the pyrrolidone derivative is less than 5% by weight, the resin particles are insufficient in action as a solubilizer or softener.

Examples of pyrrolidone derivatives include N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, N-vinyl-2-pyrrolidone, 2-pyrrolidone, N-butyl-2-pyrrolidone, 5-methyl-2-pyrrolidone, etc. These are low molecular compounds.
Of these, 2-pyrrolidone and N-methyl-2-pyrrolidone are particularly preferred from the viewpoint of ensuring the storage stability of the water-based ink composition, the promotion of film formation of resin particles, and the relatively low odor. A preferred solvent is a pyrrolidone derivative, but a lactone solvent represented by γ-butyrolactone, a sulfoxide solvent represented by dimethyl sulfoxide, or the like may be used.

1.5 Other Solvent Components The aqueous ink composition in the invention can further contain a solvent having a moisturizing action or a low surface tension. For example, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, ethylene glycol monobutyl ether , Diethylene glycol mono-n-propyl ether, ethylene glycol mono-iso-propyl ether, diethylene glycol mono-iso-propyl ether, ethylene glycol mono-n-butyl ether, ethylene glycol mono-t-butyl ether, diethylene glycol mono-n-butyl ether, tri Ethylene glycol mono-n-butyl ether, diethylene glycol mono-t-butyl ether, 1-methyl-1-methoxybuta 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, dipropylene Glycol mono-n-butyl ether, dipropylene glycol mono-n-propyl ether, dipropylene glycol mono-iso-propyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol dibutyl ether, diethylene glycol ethyl methyl ether, diethylene glycol butyl methyl ether, triethylene Glycol dimethyl ether , Tetraethylene glycol dimethyl ether, dipropylene glycol dimethyl ether, dipropylene glycol diethyl ether, tripropylene glycol dimethyl ether, methanol, ethanol, n-propyl alcohol, iso-propyl alcohol, 2,2-dimethyl-1-propanol, n-butanol, 2-butanol, tert-butanol, iso-butanol, 2-methyl-1-butanol, 3-methyl-1-butanol, 3-methyl-2-butanol, n-pentanol, 2-pentanol, 3-pentanol Water-soluble solvents such as tert-pentanol, 3-methyl-1,3-butanediol, 2-ethyl-1,3-hexanediol, and 2-methyl-1,3-propanediol.

1.6 Other Additive Components In addition to the preferred constituent materials described above, the water-based ink composition of the present invention is further provided with a pH adjuster, preservative / antifungal agent, chelating agent in terms of further improving its properties. Etc. can be added.

  Examples of the pH adjuster include potassium dihydrogen phosphate, disodium hydrogen phosphate, sodium hydroxide, lithium hydroxide, potassium hydroxide, ammonia, diethanolamine, triethanolamine, triisopropanolamine, potassium carbonate, sodium carbonate, Examples thereof include sodium hydrogen carbonate.

  Examples of antiseptics and fungicides include sodium benzoate, sodium pentachlorophenol, 2-pyridinethiol-1-oxide sodium, sodium sorbate, sodium dehydroacetate, 1,2-dibenzisothiazoline-3-one Etc. Examples of commercially available products include Proxel XL2, Proxel GXL (above trade name, manufactured by Avicia), Denside CSA, NS-500W (above trade name, manufactured by Nagase ChemteX Corporation), and the like.

  Examples of the rust inhibitor include benzotriazole.

  Examples of chelating agents include ethylenediaminetetraacetic acid and salts thereof (such as ethylenediaminetetraacetic acid dihydrogen disodium salt).

  Note that a recording medium with low ink absorbability and non-ink absorbability has a property that ink does not easily permeate, so that the drying property of the attached ink composition may not be excellent. In this case, in the ink composition, an alkyl polyol having a boiling point under 1 atm of 280 ° C. or more is substantially added in order to improve the drying property when adhering to a recording medium having low ink absorption and non-ink absorption. It is preferable not to contain. In this specification, “substantially does not contain an alkyl polyol” means, for example, that the ink does not contain 0.1% by mass or more, more preferably 0.05% by mass or more, and still more preferably Means not containing 0.01% by mass or more. A typical example of an alkyl polyol having a boiling point of 1 atm or higher at 280 ° C. is glycerin (boiling point: 290 ° C.).

1.7 Physical Properties of Aqueous Ink Composition The viscosity of the aqueous ink composition is preferably in the range of 1.5 mPa · s to 15 mPa · s at 20 ° C. Within this range, it is possible to ensure ink ejection stability in the first step described below. The viscosity of the water-based ink composition can be measured by maintaining the temperature of the water-based ink composition at 20 ° C. using a vibration viscometer VM-100AL (manufactured by Yamaichi Electronics Co., Ltd.).

  The surface tension of the water-based ink composition is preferably 20 mN / m to 40 mN / m, more preferably 25 mN / m to 35 mN / m at 25 ° C. Within this range, ink ejection stability can be ensured in the first step described below, and appropriate wettability with respect to a non-ink-absorbing or low-absorbing recording medium can be secured. The surface tension of the water-based ink composition can be measured using a surface tension meter CBVP-Z (manufactured by Kyowa Interface Science Co., Ltd.).

1.8 Method for Producing Water-Based Ink Composition The water-based ink composition in the present invention is obtained by mixing the above-described materials in an arbitrary order and removing impurities by filtering or the like as necessary. Here, the colorant is preferably prepared in advance in a state of being uniformly dispersed in an aqueous medium and then mixed in view 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.

2. Inkjet Recording Method Next, an example of each step of the inkjet recording method of the present invention will be described in detail. The ink jet recording method of the present invention includes a first step of forming an image by discharging droplets of the above-described aqueous ink composition onto a recording medium, and a second step of heating the recording medium.

2.1 First Step The first step in the ink jet recording method of the present invention is a water-based ink on a recording medium heated to a temperature range of 40 ° C. or higher and 80 ° C. or lower with a print heater or the like provided in the ink jet recording apparatus. The composition is discharged as droplets. Any of the conventionally known methods can be used as the inkjet ejection method, and in particular, a method of ejecting droplets using the vibration of a piezoelectric element (using an inkjet head that forms ink droplets by mechanical deformation of an electrostrictive element). In the recording method, excellent image recording can be performed. Heating may be performed before recording or may be performed after recording.

2.2 Second Step In the second step, the recording medium on which the inkjet image is formed is dried at 50 ° C. by a drying mechanism such as a warm air mechanism provided in the inkjet recording apparatus or a thermostatic chamber connected to the inkjet recording apparatus. This is a step of heating the aqueous ink composition discharged on the recording medium by heating to a temperature range of 110 ° C. or lower.

Ink non-absorptivity is formed by the first step of forming an image by heating a non-ink-absorbing or low-absorbing recording medium to a temperature range of 40 ° C. to 80 ° C. Alternatively, a high-quality image with little shading unevenness and bleeding can be formed on a low-absorbency recording medium.
In addition, due to the second step of heating the recording medium on which the inkjet image is formed to a temperature range of 50 ° C. or higher and 110 ° C. or lower, moisture contained in the water-based ink composition discharged onto the recording medium is quickly A film is formed by the resin particles contained in the water-based ink composition by evaporation and scattering. As a result, a high-quality image with less density unevenness and bleeding can be obtained in a short time on the recording medium with the dried ink firmly adhered.
At this time, the heating temperature of the recording medium is in the temperature range of 40 ° C. or more and 80 ° C. or less in the first step, and in the temperature range of 50 ° C. or more and 110 ° C. or less in the second step. It can be adjusted accordingly.
By setting the heating temperature in the second step to 50 ° C. or higher, evaporation and scattering of the liquid medium in the aqueous ink composition can be promoted. However, the higher the heating temperature in the second step, the higher the temperature of the ink. It is advantageous in terms of drying and abrasion resistance. However, when the heating temperature of the recording medium exceeds 90 ° C., deformation may occur depending on the type of the recording medium, and problems such as shrinkage of a recorded image may occur when the recording medium is heated and cooled. In addition, there are undesirable problems such as an increase in power consumption of the heater used for heating and an increase in exhaust heat from the ink jet printer due to the heating mechanism. It is preferable that
On the other hand, if the heating temperature in the second step is less than 50 ° C., the solvent in the water-based ink composition remains, resulting in insufficient film formation of water-insoluble resin particles, and the strength of the recorded image can be obtained. There may not be.

  The heating and drying time of the recording medium is not particularly limited as long as the liquid medium present in the water-based ink composition can be evaporated and scattered, and a film of resin particles can be formed, taking into account the solvent used, resin particles, printing speed, etc. And can be set as appropriate. The first step and the second step are not particularly limited as long as they are methods for promoting evaporation and scattering of the liquid medium present in the aqueous ink composition. Examples thereof include a method of applying heat to the recording medium, a method of blowing air on the aqueous ink composition on the recording medium, and a method of combining them. Specifically, hot air treatment such as forced air heating, radiant heating, conduction heating, high frequency drying, microwave drying, or heating by a heater is preferably used.

3. In the present invention, a non-ink-absorbing or low-absorbing recording medium is used as the recording medium.
In the present specification, “non-ink-absorbing and low-absorbing recording medium” refers to “a recording medium having a water absorption of 10 mL / m 2 or less from the start of contact to 30 msec 1/2 in the Bristow method”. . This Bristow method is the most popular method for measuring the amount of liquid absorbed in a short time, and is also adopted by the Japan Paper Pulp Technology Association (JAPAN TAPPI). For details of the test method, refer to Standard No. of “JAPAN TAPPI Paper Pulp Test Method 2000”. 51 "Paper and paperboard-Liquid absorbency test method-Bristow method".
As a non-ink-absorbing recording medium, for example, a plastic film is coated on a substrate such as a plastic film or paper that is not surface-treated for inkjet printing (that is, has no ink-absorbing layer 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. Examples of the low-ink-absorbing recording medium include printing paper such as art paper, coated paper, and matte paper.
In the present invention, the effect is particularly exhibited when polyethylene terephthalate or polypropylene is used as the plastic film.

4). Examples Hereinafter, the present invention will be described in detail with reference to examples, but the present invention is not limited thereto.

4.1 Preparation of aqueous ink composition 4.1.1 Preparation of pigment dispersion The water-based ink composition used in this example used a water-insoluble pigment as a colorant. When the pigment was added to the aqueous ink composition, a resin-dispersed pigment in which the pigment was previously dispersed with a resin dispersant was used. The pigment dispersion was prepared as follows.

  Polymeric dispersant (methacrylic acid / butyl acrylate / styrene / hydroxyethyl acrylate = copolymerized at a mass ratio of 25/50/15/10. Weight average molecular weight 12,000) 40 parts by mass of potassium hydroxide 7 parts by mass Into a mixed solution of 23 parts by mass of water and 30 parts by mass of triethylene glycol mono-n-butyl ether, the mixture is heated and stirred at 80 ° C. to conduct a polymerization reaction, thereby adjusting the polymer dispersant varnish. 2.4 kg of this varnish (solid content: 43%) is mixed with 33.0 kg of the following pigment, 1.5 kg of ethylene glycol and 8.1 kg of water, and premixed by stirring with a mixing stirrer. The pigment dispersion mixture was dispersed by a multi-pass method in a horizontal bead mill equipped with a multi-disc type impeller having an effective volume of 1.5 liters filled with 85% of 0.5 mm zirconia beads. Specifically, the bead peripheral speed was 8 m / sec, and two passes were performed at a discharge rate of 30 liters per hour to obtain a pigment dispersion mixed liquid having an average particle diameter of 325 nm. Next, circulation dispersion was performed in a horizontal annular bead mill having an effective volume of 1.5 liters filled with 95% of 0.05 mm zirconia beads. A screen having a diameter of 0.015 mm was used, and an aqueous pigment dispersion was obtained by dispersing the beads at a peripheral speed of 10 m / second and a pigment dispersion of 10 kg for 4 hours at a circulation rate of 300 liters / hour. 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)

4.1.2 Preparation of Aqueous Ink Composition Using the pigment dispersion prepared in “4.1.1 Preparation of Pigment Dispersion” above, the material composition shown in Table 1 was used for black, yellow, magenta, Water-based ink compositions having different material compositions for the four cyan colors were prepared. For each water-based ink composition, the materials shown in Table 1 are put in a container, mixed by stirring with a magnetic stirrer for 2 hours, and then filtered through a membrane filter having a pore size of 5 μm to remove impurities such as dust and coarse particles. It was prepared by. The numerical values in Table 1 all indicate mass%, and ion exchange water was added so that the total amount of ink was 100 mass%. The resin particles described in the table were a styrene acrylic acid copolymer resin having a Tg of 85 ° C., and the surfactant was a silicone-based surfactant “BYK-348” (manufactured by Big Chemie Japan Co., Ltd.). The average particle size of AQUACER 539 (AQ539) is 54 nm, the average particle size of AQUACER 537 (AQ537) is 33 nm, and the average particle size of Cerosol H-620 (Cerosol) is 200 nm. The polyethylene wax used is AQUACER 515 (manufactured by Big Chemie Japan Co., Ltd.), the melting point is 135 ° C., and the average particle size is 60 nm.

4.2 Aqueous Pigment Ink Evaluation Test Test Method A part of the printer PX-G930 (manufactured by Seiko Epson Corporation) was remodeled to produce a printer that can heat-control the recording media during recording. The following evaluations were performed using the inks listed in the examples and comparative examples. In each of the following evaluations, ink jet recording was performed with a resolution of vertical 720 dpi × horizontal 720 dpi for any of the samples.

<1> Abrasion resistance During recording, the following recording media were heated at 45 ° C., dried for 1 minute in an environment at 60 ° C. after recording, and then examined for rubbing on the recording media left at room temperature for 16 hours.
The method is a determination method for visually determining the presence or absence of rubbing of the recording surface when the recorded matter is rubbed 100 times with a Gakushin type friction fastness tester with a load of 500 g and cotton cloth.
Recording media:
(1) Cold Laminated Film (PET) Part No. PG-50L (Made by Lamy Corporation)
(2) PP synthetic paper No. YUPO 80 (UV) PAT1E (manufactured by Lintec Corporation)
Judgment criteria:
○ ・ ・ ・ ・ No scratches are observed ○ △ ・ ・ ・ ・ Slightly scratches are observed △ ・ ・ ・ ・ Scratches are observed × ・ ・ ・ ・ Large scratches are recognized

<2> Blocking resistance After recording, the following recording media were heated at 45 ° C. and dried for 1 minute in a 60 ° C. environment after recording, and then a blocking resistance test was performed by the following method.
Anti-blocking test:
The same recording surface as the recording surface of the recorded sheet is superposed so that the back surface is in contact with each other, and left at 24 ° C. under an environment of 50 ° C. and 80% RH at 10 kg load / 100 cm ² . After 24 hours, the sheet is peeled off, the state is observed, and the determination is made according to the following criteria.
Recording media:
(1) Cold Laminated Film (PET) Part No. PG-50L (Made by Lamy Corporation)
(2) PP synthetic paper No. YUPO 80 (UV) PAT1E (manufactured by Lintec Corporation)
Judgment criteria:
○ ······················································································ Blocking is partially recognized

<3> Water resistance The following recording media were heated at 45 ° C. during recording, dried for 1 minute in a 60 ° C. environment after recording, and then subjected to a water resistance test by the following method.
1 ml of tap water was attached to the recording portion of the recording sample and left for 1 minute, and then water droplets were wiped off with a cotton cloth. The recording surface was rubbed 3 times during wiping. The state of the recording part and the cotton cloth after wiping was visually observed. Evaluation was made according to the following criteria.
Recording media:
(1) Cold Laminated Film (PET) Part No. PG-50L (Made by Lamy Corporation)
(2) PP synthetic paper No. YUPO 80 (UV) PAT1E (manufactured by Lintec Corporation)
Judgment criteria:
○: There is no peeling of the ink (colorant) from the recording medium, and the cotton cloth is not colored.
X: Some of the recording medium has a part of the ink (colorant) peeled off from the medium and the cotton cloth is colored.

<4> Ejection stability The inks of Examples and Comparative Examples were filled in ink cartridges, mounted in the following printers, continuously recorded for 10 minutes without heating during printing, and all nozzles were confirmed to be ejected normally. Thereafter, the recording was heated (45 ° C.) for 1 hour of continuous recording.
The ejection stability was evaluated according to the following criteria for the presence or absence of missing dots or bends in the recorded matter thereafter.
Judgment criteria:
○ ········· Even after 1 hour has passed, there is no bending.
× ··· After 1 hour, there is a break or bending.

  The results are shown in Table 2.

  It is clear from Table 2 that inks containing paraffin wax having a melting point of 110 ° C. or less at 0.1 mass% or more and 3 mass% or less are practical levels in terms of abrasion resistance, blocking resistance, water resistance, and ejection stability. It is. It can also be seen that the use in combination with polyethylene wax is effective in improving the abrasion resistance in a medium made of PET.

Claims (8)

  Paraffin wax having a melting point of 110 ° C. or lower and at least one water-insoluble colorant, wherein the surface temperature on the recording side of the non-ink-absorbing or low-absorbing recording medium is heated to a range of 40 ° C. And an aqueous ink composition containing water and recording.   A first step in which the surface temperature on the recording side of the recording medium is heated in the range of 40 ° C. to 80 ° C. to discharge aqueous ink; and the recording medium is heated to 50 ° C. to 110 ° C. to dry the ink. The inkjet recording method according to claim 1, further comprising a second step.   The inkjet recording method according to claim 1 or 2, wherein the water-based ink composition further contains a polyethylene wax.   The inkjet recording method according to any one of claims 1 to 3, wherein the water-based ink composition does not substantially contain an alkyl polyol having a boiling point under 1 atm of 280 ° C or higher.   The inkjet recording method according to any one of claims 1 to 4, wherein the water-based ink composition contains the paraffin wax in an amount of 0.1% by mass to 3% by mass.   The water-based ink composition further comprises 1,2-alkyldiol having 5 to 7 carbon atoms, resin particles, a nonionic surfactant, and a pyrrolidone derivative. The ink jet recording method described in 1.   The inkjet recording method according to claim 1, wherein the paraffin wax has an average particle diameter of 5 nm to 400 nm.   A recorded matter recorded by the ink jet recording method according to claim 1.