JP5949107B2 - Ink jet recording method and ink jet recording apparatus - Google Patents

Description

The present invention relates to an ink jet recording method and an ink jet recording apparatus.

  2. Description of the Related Art Conventionally, an ink jet recording method for recording images and characters with fine ink droplets ejected from a recording head has been used mainly for recording on the surface of an ink-absorbing recording medium such as paper. As an ink composition used in such an ink jet recording method, a solution in which a coloring material such as various dyes and / or pigments is dissolved or dispersed in a mixture having a high boiling point organic solvent and water is widely used. Such a high boiling point organic solvent is excellent in low volatility and water retention ability, and thus contributes to prevention of drying of the nozzles of the inkjet recording head.

On the other hand, there is a demand for an inkjet recording method capable of recording not only on a water-absorbing recording medium such as paper but also on a non-absorbing or low-absorbing recording medium such as printing paper, synthetic paper, and film. Furthermore, an ink jet recording method capable of realizing high-speed printing is required.
For example, Patent Document 1 discloses 4 masses of latex particles (average particle size 230 nm, glass transition temperature −20 ° C. to + 30 ° C.) prepared by reacting monomers consisting of styrene, hexyl methacrylate, ethylene glycol dimethacrylate, and methacrylic acid. %, 6% by weight 1,2-hexanediol, 6% by weight 2-pyrrolidone, 5% by weight dipropylene glycol, 4% by weight diethylene glycol, and 0.5% by weight surfactant ( Ink jet ink (100% by mass in total) comprising a carbon black pigment encapsulated with 2% by mass of a styrene acrylic copolymer and water (remainder) from a thermal inkjet print head. Disclosed is a method of printing on a porous vinyl substrate. Are (Examples 1-3 in Patent Document 1, paragraph 0047).

Patent Document 2 discloses 2.18% by mass of a magenta pigment dispersion, 1% by mass of a surfactant (Silwet L-7608), 10% by mass of diethylene glycol, and 5% for recording on a non-absorbent substrate. An ink containing mass% dipropylene glycol methyl ether, 3 mass% 2-pyrrolidone, 2 mass% polymer latex, and water is disclosed (paragraph 0052 of Patent Document 2).
Patent Document 3 discloses a recording ink composed of a colorant and a resin, the content of a solid component being solid at 25 ° C. being 20% or more, and the content of a liquid component being liquid at 25 ° C. being 20% or less. Is disclosed. Specifically, 6% by mass of the surface-treated carbon black dispersion, 18% of an acrylic silicone emulsion (average particle diameter 150 nm, glass transition temperature −15 ° C. to −6 ° C.), and 5% by mass of 1,3-butanediol. 2% by mass of 2-pyrrolidone, 2% by mass of 2-ethyl-1,3-hexanediol, 1% by mass of a fluorosurfactant, 0.1% by mass of a silicone emulsion antifoaming agent, and a minor component Ink composed of water and water is disclosed (paragraph 0215 of Patent Document 3).

JP 2005-220352 A JP 2004-114691 A JP 2007-217671 A

However, since the ink for inkjet recording disclosed in Patent Documents 1 to 3 or the recorded matter obtained by the inkjet printing method has a high content of high-boiling organic solvent, it is dried in high-speed printing on ink non-absorbent media. The problem that the property and the abrasion resistance are insufficient arises.
On the other hand, with an ink composition that does not sufficiently contain a high-boiling organic solvent, the nozzles of the inkjet recording head cannot be prevented from drying, and the nozzles tend to be clogged.
Accordingly, some aspects of the present invention provide an ink jet recording method capable of printing on various recording media by solving the above-described problems, that is, ink absorbability, ink Provided is an ink jet recording method which is excellent in drying property and abrasion resistance and can reduce nozzle clogging even when recording on any recording medium having low absorption and further ink non-absorption. .

  The inventor of the present application has made extensive studies in order to solve the above problems, and has obtained the following knowledge. First, in an ink jet recording method for forming an image on an ink-absorbing and non-absorbing or low-absorbing recording medium, in order to achieve high-speed printing, the drying speed of the ink on the recording medium is set. Need to increase. Means for increasing the drying speed include increasing the temperature at which the recording medium to which the ink is attached is heated, and controlling the type and content of a low-volatile and high-boiling solvent as the ink material.

  In the printing method disclosed in Patent Document 1, for example, when the printing speed is increased by changing the recording at 16 passes to 8 passes, on a non-absorbable recording medium such as a polypropylene film (PP film). This causes the problem of slow drying of the ink. As a result, it was found that the ink was poorly fixed to the PP film, and the resulting recorded matter was inferior in abrasion resistance. Further, in the case of the ink disclosed in Patent Document 2, there arises a problem that the ink on the non-absorbable recording medium, for example, the PP film, is not sufficiently dried. As a result, it was found that the ink was poorly fixed to the PP film, and the resulting recorded matter was inferior in abrasion resistance. Similarly, in the case of the ink disclosed in Patent Document 3, there arises a problem that the ink on the non-absorbable recording medium, for example, the ink on the PP film, cannot obtain sufficient abrasion resistance.

  Therefore, as a result of further studies by the inventors of the present application, the problem that the drying of the ink is slow on a non-ink-absorbing or low-absorbing recording medium is substantially caused by a certain pyrrolidone derivative such as 2-pyrrolidone. It has been found that the problem can be solved by not using it or by substantially not containing a solvent having a boiling point of 280 ° C. or higher such as glycerin. That is, the 2-pyrrolidone derivative has a relatively high boiling point, lowers the drying property of the ink on the non-ink-absorbing recording medium, and clogs the nozzles of the inkjet recording head despite the high boiling point. The prevention effect is small. A solvent having a boiling point of 280 ° C. or higher such as glycerin is effective for preventing clogging of the nozzle, but the ink is very difficult to dry on a recording medium having no ink absorption or low absorption. Therefore, the inventors of the present application include an alkyl polyol having a boiling point of 190 ° C. or more and 250 ° C. or less and a content of the alkyl polyol having a boiling point of 220 ° C. or more and 250 ° C. or less by 2% or more and 10% or less. The present inventors have found that the problem of coexistence of drying characteristics of ink on a non-ink-absorbing or low-absorbing recording medium and prevention of clogging due to nozzle drying can be solved to some extent. Further, in order to obtain sufficient abrasion resistance, the above-mentioned recording medium containing a resin having a heat distortion temperature of 40 ° C. or higher and non-absorbing or low absorbing ink is heated at 35 to 100 ° C. The present invention has been completed by finding out that the problems can be solved.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following aspects or application examples.

[Application Example 1]
10% by weight or more and 25% by weight of a coloring material, two or more kinds of resin particles having a heat distortion temperature of 40 ° C. or more, and two or more kinds of alkyl polyols having a boiling point of 190 ° C. or more and 250 ° C. or less corresponding to 1 atmosphere. The content of the alkyl polyol having a boiling point of 220 ° C. or higher and 250 ° C. or lower is 2% by mass or more and 10% by mass or less, and the boiling point of 1 atm or lower is 240%. An image forming step of forming an image by ejecting and adhering an ink composition that substantially does not contain a pyrrolidone derivative at or above C to a recording medium, and heating the recording medium at 35 to 100C And a process.

  Application Example 2 The ink jet recording method according to the application example is characterized in that the ink composition does not substantially contain a resin having a glass transition temperature of 10 ° C. or lower.

  Application Example 3 The ink jet recording method described in the application example is characterized in that the ink composition does not substantially contain an alkyl polyol having a boiling point of 280 ° C. or higher at 1 atm.

Application Example 4 In the ink jet recording method described in the above application example, the recording medium is an ink non-absorbing or low-absorbing recording medium, and an image recording speed on the recording medium is 0.3 m ² / It is characterized by being more than minutes.
Application Example 5 The ink jet recording method described in the above application example further includes the following step (1) or (2).
(1) A step of forming a background image by discharging and adhering a background ink composition toward an area of a recording medium to which the ink composition is attached, which is performed before the image forming step.
(2) A step of forming a background image by discharging and adhering the background ink composition toward an area of the recording medium to which the ink composition is adhered, which is performed after the image forming step.

Application Example 6 The ink jet recording method according to the application example is characterized in that the amount of the ink composition deposited per unit area in at least a partial region of the image is 10 mg / inch ² or more.

  Application Example 7 The ink jet recording method described in the application example is characterized in that the ink composition does not substantially contain a pyrrolidone derivative.

  Application Example 8 One aspect of a recording apparatus according to the present invention is characterized in that recording is performed using the ink composition.

  Application Example 9 One aspect of the recorded matter according to the present invention is characterized by being recorded using the above ink composition.

  Hereinafter, preferred embodiments of the present invention will be described in detail. The embodiment described below describes an example of the present invention. In addition, the present invention is not limited to the following embodiments, and includes various modifications that are implemented within a range that does not change the gist of the present invention.

1. Ink composition 1.1. Color Material The ink composition according to the present embodiment includes a color material. Examples of the color material include dyes and pigments, and pigments are preferable from the viewpoint of water resistance, gas resistance, light resistance, and the like.
As such a pigment, any of known inorganic pigments, organic pigments, and carbon black can be used. These pigments are preferably contained in the range of 0.5% by mass or more and 20% by mass or less, more preferably in the range of 1% by mass or more and 15% by mass or less with respect to the total amount of the ink composition.

Although it does not specifically limit as an inorganic pigment, For example, carbon black, iron oxide, and titanium dioxide are mentioned.
Although it does not specifically limit as said carbon black, For example, furnace black, lamp black, acetylene black, and channel black (CI pigment black 7) are mentioned. Further, as a commercially available product of carbon black, for example, No. 2300, 900, MCF88, no. 20B, no. 33, no. 40, no. 45, no. 52, MA7, MA8, MA100, no. 2200B (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 (all trade names, Evonik Degussa Japan Co., Ltd.), Conductex SC, Raven 1255, 5750, 5250, 5000, 3500, 1255, 700 (all trade names, manufactured by Columbia Carbon Japan Co., Ltd.), Regar 400R 330R, 660R, Mogul L, Monarch 700, 800, 880, 900, 1000, 1100, 1300, 1400, Elftex 12 (all trade names, manufactured by Cabot Japan Co., Ltd.).

An inorganic pigment may be used individually by 1 type, and may be used in combination of 2 or more type.
Examples of organic pigments include, but are not limited to, quinacridone pigments, quinacridone quinone pigments, dioxazine pigments, phthalocyanine pigments, anthrapyrimidine pigments, ansanthrone pigments, indanthrone pigments, flavanthrone pigments, Examples include perylene pigments, 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 include the following.

Examples of pigments used for cyan ink 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, 60, 65, 66, C.I. I. Bat Blue 4 and 60 are listed. Among them, C.I. I. At least one of Pigment Blue 15: 3 and 15: 4 is preferable.
Examples of pigments used in magenta ink 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, C.I. I. Pigment violet 19, 23, 32, 33, 36, 38, 43, 50. Among them, C.I. I. Pigment red 122, C.I. I. Pigment red 202, and C.I. I. One or more selected from the group consisting of Pigment Violet 19 is preferred.

  Examples of pigments used in yellow ink 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. Among them, C.I. I. One or more selected from the group consisting of CI Pigment Yellow 74, 155, and 213 are preferred.

In addition, as a pigment used for inks of colors other than the above, such as green ink and orange ink, conventionally known pigments can be used.
In order to apply the pigment to the ink composition, the pigment needs to be stably dispersed and held in water. Examples of the method include a method of dispersing with a dispersion resin to be described later (hereinafter, a pigment treated by this method is referred to as “resin dispersed pigment”), a water-soluble surfactant and / or a water-dispersible surfactant. A method of dispersing with a surfactant (hereinafter, the pigment treated by this method is referred to as “surfactant-dispersed pigment”), a hydrophilic functional group is chemically and physically introduced on the surface of the pigment particles, For example, a method of allowing dispersion and / or dissolution in water without a dispersant such as a resin or a surfactant (hereinafter, a pigment treated by this method is referred to as a “surface-treated pigment”), and the like. The ink composition according to the present embodiment can use any of a resin-dispersed pigment, a surfactant-dispersed pigment, and a surface-treated pigment, and can be used in the form of a mixture of plural kinds as required, but at least a resin It preferably contains a dispersed pigment.

  The amount of the dispersion resin or the surfactant added to the pigment is preferably 1 part by mass to 100 parts by mass, and 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 a method for dispersing the 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 surfactant for the surfactant-dispersed pigment, For surface-treated pigments, add surface-treated pigment and water, and water-soluble organic solvents / neutralizers, etc., as necessary, and then use a 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 a sonic 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.

  Here, the average particle diameter in this specification is based on volume. As a measuring method, for example, it can be measured by a particle size distribution measuring apparatus using a laser diffraction scattering method as a measurement principle. Examples of the particle size distribution measuring apparatus include a particle size distribution meter (for example, Microtrac UPA manufactured by Nikkiso Co., Ltd.) having a dynamic light scattering method as a measurement principle.

The dye that can be used as the color material is not particularly limited, and an acid dye, a direct dye, a reactive dye, and a basic dye can be used.
Examples of the dye include, but are not limited to, C.I. I. Acid Yellow 17, 23, 42, 44, 79, 142, C.I. I. Acid Red 52, 80, 82, 249, 254, 289, C.I. I. Acid Blue 9, 45, 249, C.I. I. Acid Black 1, 2, 24, 94, C.I. I. Food Black 1, 2, C.I. I. Direct Yellow 1, 12, 24, 33, 50, 55, 58, 86, 132, 142, 144, 173, C.I. I. Direct Red 1, 4, 9, 80, 81, 225, 227, C.I. I. Direct Blue 1, 2, 15, 71, 86, 87, 98, 165, 199, 202, C.I. I. Directed Black 19, 38, 51, 71, 154, 168, 171, 195, C.I. I. Reactive Red 14, 32, 55, 79, 249, C.I. I. Reactive black 3, 4, and 35 are mentioned.

In addition, a color material may be used individually by 1 type and may be used in combination of 2 or more type. The content of the color material is preferably 0.5 to 10% by mass with respect to the total mass (100% by mass) of the ink composition.
Examples of the background ink composition used when the recording method of the above embodiment further includes a background image forming step include, for example, a white ink that imparts excellent concealing property, and a gold or silver color that imparts glitter. Such a metallic ink, and a clear ink for pretreatment and base formation. Color materials used for these inks may be selected from the above.

1.2. Resin Particles Another feature of the ink composition according to the present embodiment is that the ink composition contains two or more kinds of resin particles having a heat distortion temperature of 40 ° C. or higher. The heat distortion temperature is a word indicating any of glass transition temperature (Tg), minimum film forming temperature (MFT), and melting point.

First, when the thermal deformation temperature of the resin particles contained in the ink composition is 40 ° C. or higher, the fixability of the ink is improved, and the abrasion resistance of the image is improved. The heat distortion temperature is preferably 40 ° C. or more, more preferably 40 to 150 ° C., and even more preferably 50 to 150 ° C. in order to improve the fixability of the ink.
In addition, since two or more kinds of resin particles having a heat distortion temperature of 40 ° C. or more are contained in the ink composition, the ink has excellent fixability, so that the image has excellent abrasion resistance, and clogging reliability is improved. Can be secured. In order to further improve the fixing property of the ink and to ensure clogging reliability, it is preferable that the thermal deformation temperature of all the resin particles contained in the ink composition is 40 ° C. or higher.

  Examples of the resin particles include, but are not limited to, dispersion resins, resin emulsions, and waxes (emulsions) described below. Among these, since the fixing property of the ink is further improved, one type is a wax (emulsion) as a combination of two or more types of resin particles, and the other type is a styrene-acrylic acid copolymer resin (emulsion). ). In addition, this preferable combination does not restrict | limit that another kind of resin particle is contained.

On the other hand, it is preferable that the ink composition does not substantially contain resin particles having a Tg of 10 ° C. or lower. Thereby, the abrasion resistance of the image is further improved.
In addition, the glass transition temperature (Tg) in this specification can be calculated | required from a DSC curve based on JISK7121.

1.2.1.1. Dispersion Resin The ink composition according to the present embodiment may contain a dispersion resin. The dispersion resin may be either a water-soluble resin or a water-insoluble resin, but is preferably a water-insoluble resin. The structure of the resin dispersant of the water-insoluble resin is not particularly limited, but preferred examples are given.

  The first example is made of a block copolymer resin of a monomer having a hydrophobic group and a monomer having a hydrophilic group, and contains at least a monomer having a salt-forming group.

  Monomers having a hydrophobic group are methyl methacrylate, ethyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-amyl methacrylate, isoamyl methacrylate, n-hexyl methacrylate, 2-ethylhexyl methacrylate, octyl methacrylate, decyl methacrylate, dodecyl. Methacrylates such as methacrylate, octadecyl methacrylate, cyclohexyl methacrylate, phenyl methacrylate, benzyl methacrylate, glycidyl methacrylate, vinyl esters such as vinyl acetate, vinylcyan compounds such as acrylonitrile and methacrylonitrile, styrene, α-methylstyrene, Vinyltoluene, 4-t-butylstyrene, rubber Rusuchiren, vinyl anisole, include aromatic vinyl monomers such as vinyl naphthalene, may also be used alone, or a combination of two or more kinds.

  Examples of the monomer having a hydrophilic group include polyethylene glycol monomethacrylate, polypropylene glycol monomethacrylate, and ethylene glycol / propylene glycol monomethacrylate, which may be used alone or in combination of two or more. In particular, polyethylene glycol (2-30) monomethacrylate, polyethylene glycol (1-15) / propylene glycol (1-15) monomethacrylate, polypropylene glycol (2-30) methacrylate, methoxypolyethylene glycol (2-30) methacrylate, methoxy By using a monomer component constituting a branched chain such as polytetramethylene glycol (2-30) methacrylate and methoxy (ethylene glycol / propylene glycol copolymer) (1-30) methacrylate, the gloss of the printed image is improved. .

  Monomers having a salt-forming group include acrylic acid, methacrylic acid, styrene carboxylic acid, maleic acid and the like, and each can be used alone or in combination of two or more.

  Furthermore, a macromonomer such as a styrene macromonomer or a silicone macromonomer having a polysynthetic functional group at one end, or other monomers can be used in combination.

  The second example is a water-insoluble resin having a hydrophilic structural unit (a) and a hydrophobic structural unit (b). The hydrophilic structural unit (a) is not particularly limited as long as it is derived from a hydrophilic group-containing monomer, and even if it is derived from one kind of hydrophilic group-containing monomer, it contains two or more hydrophilic groups. It may be derived from a monomer. The hydrophilic group is not particularly limited, and may be a dissociable group or a nonionic hydrophilic group.

  The water-insoluble resin in the present invention includes a dissociable group and / or a nonionic hydrophilic group using a monomer having a dissociable group (dissociable group-containing monomer) and / or a monomer having a nonionic hydrophilic group. Can be introduced.

  The dissociable group is preferable from the viewpoint of stability in an emulsified or dispersed state. Examples of the dissociable group include a carboxyl group, a phosphoric acid group, and a sulfonic acid group. Among these, a carboxyl group is preferable from the viewpoint of dispersion stability when an ink composition is formed.

  The hydrophilic group-containing monomer is preferably a dissociable group-containing monomer, and more preferably a dissociable group-containing monomer having a dissociable group and an ethylenically unsaturated bond. Examples of the dissociable group-containing monomer include an unsaturated carboxylic acid monomer, an unsaturated sulfonic acid monomer, and an unsaturated phosphoric acid monomer.

  The hydrophobic structural unit (b) preferably includes a structural unit having an aromatic ring bonded to an atom forming the main chain via a linking group. In such a structural unit having an aromatic ring, the aromatic ring has a structure in which the aromatic ring is bonded to an atom forming the main chain of the water-insoluble resin through a linking group and is not directly bonded to an atom forming the main chain of the water-insoluble resin. Since an appropriate distance is maintained between the hydrophobic aromatic ring and the hydrophilic structural unit, the water-insoluble resin and the pigment are likely to interact with each other and are strongly adsorbed to further improve dispersibility. .

  A more detailed preferred monomer type of the second example is described in JP2011-162692.

  The molecular weight of the resin dispersant is preferably in the range of 1,000 to 200,000 as the weight average molecular weight, and more preferably in the range of 3,000 to 150,000. When the molecular weight is in the above range, the pigment is stably dispersed in water, and viscosity control when applied to the ink composition is easy.

  Moreover, it is preferable that it is the range of about 20 or more as an acid value, and it is more preferable that it is the range of 50-150. 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 the recorded matter recorded with the ink composition using the pigment particle becomes good.

  Furthermore, a commercially available product can be used as the dispersion resin. Specifically, Joncryl 67 (weight average molecular weight: 12,500, acid value: 213, Tg: 73 ° C.), Joncryl 678 (weight average molecular weight: 8,500, acid value: 215, Tg: 101 ° C.), John Kuryl 586 (weight average molecular weight: 4,300, acid value: 110, Tg: 66 ° C.), Joncryl 611 (weight average molecular weight: 8,100, acid value: 53, Tg: 50 ° C.), Joncryl 680 (weight) Average molecular weight: 4,900, acid value: 215), joncryl 682 (weight average molecular weight: 1,750, acid value: 238, Tg: 57 ° C.), joncryl 683 (weight average molecular weight: 8,000, acid value) : 160, Tg: 74 ° C.), Joncryl 690 (weight average molecular weight: 16,500, acid value: 240, Tg: 102 ° C.) (above trade name, manufactured by BASF Japan Ltd.), etc. And the like.

  Dispersion resin may be used individually by 1 type, and may be used in combination of 2 or more type. Further, the content of the dispersion resin is not particularly limited, and may be appropriately determined as necessary.

1.2.2. Resin Emulsion The ink composition of this embodiment may contain a resin emulsion. The resin emulsion has the effect of improving the abrasion resistance of the image by sufficiently fixing the ink composition onto the recording medium by forming a resin film together with the wax (emulsion) when the recording medium is heated. Demonstrate. Therefore, the resin emulsion is preferably a thermoplastic resin. Due to the above effects, a recorded matter recorded using an ink composition containing a resin emulsion is excellent in abrasion resistance on a non-ink-absorbing or low-absorbing recording medium.

  The resin emulsion that functions as a binder is contained in the ink composition in an emulsion state. By including a resin functioning as a binder in the ink composition in an emulsion state, it is easy to adjust the viscosity of the ink composition to an appropriate range in the ink jet recording system, and the storage stability and ejection stability of the ink composition. It will be excellent.

  Examples of the resin emulsion include, but are not limited to, (meth) acrylic acid, (meth) acrylic acid ester, acrylonitrile, cyanoacrylate, acrylamide, olefin, styrene, vinyl acetate, vinyl chloride, vinyl alcohol, vinyl ether, vinyl pyrrolidone. , Vinyl pyridine, vinyl carbazole, vinyl imidazole, and vinylidene chloride homopolymers or copolymers, fluororesins, and natural resins. Among them, at least one of (meth) acrylic resin and styrene- (meth) acrylic acid copolymer resin is preferable, and at least one of acrylic resin and styrene-acrylic acid copolymer resin is more preferable, styrene. -Acrylic acid copolymer resin is more preferable. In addition, said copolymer may be any form among a random copolymer, a block copolymer, an alternating copolymer, and a graft copolymer.

  As said resin emulsion, what is obtained by a well-known material and a manufacturing method may be used, and a commercial item may be used. Although not limited to the following as the said commercial item, For example, micro gel E-1002, micro gel E-5002 (above brand name, product made by Nippon Paint Co., Ltd.), Bon coat 4001, Bon coat 5454 (above brand name, DIC Corporation) SAE 1014 (trade name, manufactured by Nippon Zeon Co., Ltd.), Cybinol SK-200 (trade name, manufactured by Seiden Chemical Co., Ltd.), Jongkrill 390, Jongkrill 711, Jongkrill 511, Jongkrill 7001, Jongkrill 632, John Krill 741, John Krill 450, John Krill 840, John Krill 74J, John Krill HRC-1645J, John Krill 734, John Krill 852, John Krill 7600, John Krill 775, John Krill 537J, John Krill 1535, G Nkrill PDX-7630A, John Krill 352J, John Krill 352D, John Krill PDX-7145, John Krill 538J, John Krill 7640, John Krill 7641, John Krill 631, John Krill 790, John Krill 780, John Krill 7610 , Manufactured by BASF Japan Ltd.).

  As the resin emulsion, vinyl acetate polymers and urethane polymers can be used, and those obtained by known materials and methods can also be used. Furthermore, commercially available products can also be used. For example, as the vinyl acetate polymer particles, Polysol S-5, S-6, S-5500 (above, trade name, manufactured by Showa Polymer Co., Ltd.), Bond CH2, CH3 , CH5, CH7, CH18 (above trade name, manufactured by Konishi Co., Ltd.) and other vinyl acetate polymer polymer particles, or Panflex OM-4000, OM-4200 (over trade name, manufactured by Kuraray Co., Ltd.), Sumikaflex 201HQ , 305HQ, 355HQ, 400HQ, 401HQ, 408HQ, 410HQ, 450HQ, 455HQ, 456HQ, 460HQ, 465HQ, 467HQ, 470HQ, 510HQ, 520HQ, 752, 755 (above trade name, manufactured by Sumitomo Chemical Co., Ltd.), Denka EVA-Tex 50, 55N, 59, 60 65, 70, 75, 80, 81, 82, 88, 90, 100, 170 (above trade names, manufactured by Denki Kagaku Kogyo Co., Ltd.), Chemipearl V100, V200, V300, EV210H, (above trade names, Mitsui Chemicals, Inc.) Manufactured), Vini Blanc 3302, 1570, 1570J, 1570K, 1570L, 1540K, 1540L, A20J2, A23J1, A23J2, A34G2, A68J1, 4495LL, A23P2E, A68J1N, A70J9, B90J9, TLE-383, 4018, A22J7 1157, 1502B, 1588C, 1588CL, 1588C, 1588FD, 1080, 1087, 1090B, 1571, A22J7-F2, 4470, 4485LL, 4495LL, 1042F, 1008, G -6170, GV-6181, 1002, 1017-AD, KM-01, 1225, 1245L (trade name, manufactured by Nissin Chemical Industry Co., Ltd.) and other ethylene-vinyl acetate copolymer polymer particles, or Sumikaflex 900HL , 950HQ, 951HQ (trade name, manufactured by Sumitomo Chemical Co., Ltd.) and other ethylene / vinyl acetate / (meth) acrylic acid copolymer particles; or Sumikaflex 850HQ (trade name, manufactured by Sumitomo Chemical Co., Ltd.) And the like, and commercially available vinyl acetate polymer polymer particles such as ethylene / vinyl acetate / vinyl chloride copolymer polymer particles. In particular, ethylene-vinyl acetate polymer particles obtained by mixing about 8 to 35% by weight of ethylene monomer with vinyl acetate monomer and emulsion polymerization under high pressure to emulsify are preferable. It has excellent alkali resistance, and also improves adhesion to polyolefin films such as polypropylene and polyethylene, and abrasion resistance. The ethylene-vinyl acetate copolymer preferably has a vinyl acetate content of 8 to 35% by weight, particularly 12 to 30% by weight, from the standpoint of media adhesion, abrasion resistance, water resistance and the like.

  Examples of urethane resins include Takelac W-6021, W-5030, W-6061, WS-5000 (above trade names, manufactured by Mitsui Chemicals), Resamine D-1060, D-2020, D-4080, D-4200. , D-6300, D-6455 (above trade name, manufactured by Dainichi Seika Kogyo Co., Ltd.), Superflex 90, Superflex 107M, Superflex 110, Superflex 130, Superflex 150, Superflex 300, Superflex 410, Superflex 700 and Superflex 820 (above trade name, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) can be mentioned.

  A method for synthesizing the above resin emulsion is shown below. However, it is not particularly limited and may be synthesized by any method, 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 of a component constituting a desired polymer particle, and polymerization (that is, emulsion polymerization) is performed. A method of obtaining particles by dissolving in a water-soluble organic solvent and mixing the solution in water and then removing the water-soluble organic solvent by distillation, etc., dissolving the polymer in a water-insoluble organic solvent and dissolving the solution together with the dispersant in an aqueous solution And the like to obtain particles by mixing. Said method can be suitably selected according to the kind and characteristic of the polymer to be used. The dispersant that can be used for dispersing the polymer 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, etc.), nonionic surfactants (for example, polyoxyethylene alkyl ethers, polyoxyethylene alkyl esters, polyoxyethylene sorbitan fatty acid esters, polyoxyethylene alkylphenyl ethers). These may be used alone or in combination of two or more. It can be used by mixing.

The average particle size of the resin emulsion is preferably in the range of 5 nm to 400 nm, more preferably in the range of 20 nm to 300 nm, in order to further improve the storage stability and ejection stability of the ink.
The content of the resin emulsion is preferably in the range of 0.5 to 7% by mass with respect to the total mass (100% by mass) of the ink composition. When the content is within the above range, the solid content concentration can be lowered, so that the discharge stability can be further improved.

1.2.3. Wax The ink composition of the present embodiment preferably contains a wax. Furthermore, it is more preferable that one of the two or more types of resin particles having a heat distortion temperature of 40 ° C. or higher contained in the ink composition is a wax. When the ink composition contains a wax, the ink absorbability, or the fixability of the ink composition on a non-absorbing and low absorbing recording medium is further improved. Among the waxes, an emulsion type is more preferable. Examples of the wax include, but are not limited to, a polyethylene wax emulsion, a paraffin wax emulsion, and a polyolefin wax. Especially, since it is excellent in abrasion resistance, at least any one of a polyethylene wax emulsion and a paraffin wax emulsion is preferable.
In the present specification, the “wax emulsion” means a product obtained by dispersing solid wax particles in water mainly using a surfactant.

1.2.3.1. Paraffin Wax Emulsion When the ink composition contains a paraffin wax emulsion, slip performance is imparted to the recorded matter, and the ink has excellent abrasion resistance. In addition, since paraffin wax has water repellency, the water resistance of the recorded matter can be improved.
The “paraffin wax” in the present specification means a so-called petroleum wax, which is mainly composed of a linear paraffinic hydrocarbon (normal paraffin) having about 20 to 30 carbon atoms and a small amount of iso (iso). -It means a mixture of hydrocarbons containing paraffin and having a weight average molecular weight of about 300 to 500.

  When the ink composition contains paraffin wax in an emulsion state, the viscosity of the ink is easily adjusted to an appropriate range in the ink jet recording method, and the storage stability and ejection stability of the ink are further improved. Can do.

  The melting point of the paraffin wax emulsion is preferably 110 ° C. or lower in order to further strengthen the film of the recorded material and further improve the abrasion resistance of the image. On the other hand, the lower limit of the melting point of the paraffin wax emulsion is preferably 60 ° C. or higher in order to prevent the recording surface from being dried and sticky. Further, the melting point is more preferably 70 to 95 ° C. in order to further improve the ink ejection stability.

  The average particle size of the paraffin wax emulsion is preferably in the range of 5 nm to 400 nm, more preferably 50 nm to 200 nm, in order to obtain a stable emulsion state and further improve the storage stability and ejection stability of the ink. Range. A commercially available product may be used as it is as the paraffin wax emulsion. Examples of the commercially available products include, but are not limited to, AQUACER 537 and AQUACER 539 (trade names, manufactured by Big Chemie Japan Co., Ltd.).

  The content (in terms of solid content) of the paraffin wax emulsion is preferably in the range of 0.1 to 3% by mass, more preferably in the range of 0.3 to 2% by mass with respect to the total mass (100% by mass) of the ink. The range of 0.3 to 1.5% by mass is more preferable. When the content is within the above range, an image having excellent abrasion resistance, blocking resistance, and water resistance can be formed on a non-ink-absorbing or low-absorbing recording medium, and The ink can be excellent in preventing clogging.

1.2.3.2. Polyethylene wax emulsion When the ink composition contains a polyethylene wax emulsion, the ink can have excellent abrasion resistance.

  For example, a polyethylene wax emulsion is produced by polymerizing ethylene, or by producing polyethylene for general molding by reducing the molecular weight by thermal decomposition. The polyethylene wax is oxidized to add a carboxyl group or a hydroxyl group, and further emulsified using a surfactant to obtain a polyethylene wax emulsion in the form of an aqueous wax emulsion having excellent stability.

  A commercially available product may be used as it is as the polyethylene wax emulsion. The commercial products are not limited to the following, but, for example, Nopcoat PEM17 (trade name, manufactured by San Nopco Co., Ltd.), Chemipearl W4005 (trade name, manufactured by Mitsui Chemicals), AQUACER 507, AQUACER 515, AQUACER 539 (above trade names, BIC Chemie)・ Japan Co., Ltd.).

  The average particle size of the polyethylene wax emulsion is preferably in the range of 5 nm to 400 nm, more preferably in the range of 50 nm to 200 nm, in order to further improve the storage stability and ejection stability of the ink.

  The content of the polyethylene wax emulsion (in terms of solid content) is preferably in the range of 0.1 to 3% by mass, and 0.3 to 2% by mass, independently of the total mass (100% by mass) of the ink. Is more preferable, and a range of 0.3 to 1.5% by mass is more preferable. When the content is within the above range, the ink can be solidified and fixed satisfactorily even on a non-ink-absorbing or low-absorbing recording medium, and the storage stability and clogging reliability of the ink can be achieved. And the discharge stability is further improved.

1.3. Alkyl polyols The ink composition according to the present embodiment preferably comprises alkyl polyols having a boiling point within the range of 190 to 250 ° C. under the equivalent of 1 atm. The ink composition according to the present embodiment includes alkyl polyols that satisfy the above-described boiling range, so that the wettability, penetrability, and drying properties of the ink composition are less affected by the type of recording medium. Can be controlled. As a result, it is possible to record images having excellent fixability on various recording media, and it is possible to reduce clogging of the nozzles of the inkjet recording head.

  Further, the alkyl polyols in the ink composition according to the present embodiment are incorporated into an ink vehicle of a glycol ether having an HLB value calculated by the aforementioned Davis method in the range of 5.0 to 7.8. It also has the property of a solubilizing agent.

In addition, the boiling point under 1 atm in this specification can be measured using a thermal analyzer.
Examples of the alkyl polyol having a boiling point of 190 ° C. or higher and 250 ° C. or lower include, but are not limited to, for example, 1,2-butanediol (boiling point 194 ° C.), ethylene glycol (boiling point 196 ° C.), 1,2-ethanediol. (Boiling point 197 ° C.), 1,2-propanediol (boiling point 188 ° C.), 2-methylpentane-2,4-diol (boiling point 197 ° C.), dibutylene glycol (boiling point 202 ° C.), 1,3-butylene glycol ( Boiling point 207 ° C) 1,3-butanediol (boiling point 208 ° C), 1,2-pentanediol (boiling point 210 ° C), 1,3-propanediol (boiling point 210 ° C), 3-methyl-1,3-butanediol (Boiling point 203 ° C.), 2-methyl-1,3-propanediol (boiling point 214 ° C.), and 2,2-dimethyl-1,3-propanediol ( 210 ° C.), 1,2-hexanediol (boiling point 223 ° C.), 2-ethyl-2-methyl-1,3-propanediol (boiling point 226 ° C.), 1,2-heptanediol (boiling point 227 ° C.), 1 , 4-butanediol (boiling point 230 ° C.), 2-methyl-2-propyl-1,3-propanediol (boiling point 230 ° C.), dipropylene glycol (boiling point 230 ° C.), 2-ethyl-1,3-hexanediol (Boiling point 244 ° C.), 3-methyl-1,5-pentanediol (249 ° C.), and 1,6-hexanediol (boiling point 250 ° C.).

  Among the solvents described above, 1,2-butanediol (boiling point 194 ° C.), 1,3-butanediol (boiling point 208 ° C.), 1,2-pentanediol (boiling point 210 ° C.), 1,2-hexanediol ( Boiling point 223 ° C.), 3-methyl-1,5-pentanediol (249 ° C.), and 3-methyl-1,3-butanediol (boiling point 203 ° C.) are particularly preferable from the viewpoints of moisture retention and drying properties.

  On the other hand, it is preferable that the ink composition does not substantially contain alkyl polyols having a boiling point of 280 ° C. or higher at 1 atm. By including an alkyl polyol having a boiling point of 280 ° C. or higher at 1 atm, the drying property of the ink composition tends to deteriorate. As a result, in various recording media, in particular, non-ink-absorbing or low-absorbing recording media, not only image bleeding is noticeable, but also the abrasion resistance of the image due to insufficient fixing of the ink. Inferior. For example, examples of the alkyl polyol having a boiling point of 280 ° C. or higher at 1 atm include glycerin having a boiling point of 290 ° C. at 1 atm.

  The ink composition according to the present embodiment preferably contains at least 10% by mass to 25% by mass of a polyol having a boiling point in the range of 190 to 250 ° C. at 1 atm, and particularly at 1 atm. The alkyl polyol having a boiling point of 220 to 250 ° C. is preferably 2% by mass or more and 10% by mass or less. More preferably, the content of the alkyl polyol having a boiling point of 220 to 250 ° C. at 1 atm is less than half of the total amount of polyols having a boiling point of 190 to 250 ° C. at 1 atm. Preferably there is. Even more preferably, it is preferable to contain a polyol having a boiling point in the range of 190 to 250 ° C. at 1 atm in an amount of 12 to 18% by mass, and even more preferably in a range of 230 to 250 ° C. The content of the alkyl polyol is 2% by mass or more and 4% by mass or less.

  In addition, if the boiling point of the alkyl polyols contained in the ink composition at 1 atm is less than 190 ° C., the ink composition may become more dry and the nozzles of the inkjet recording head may be clogged. . When the boiling point at 1 atm is higher than 250 ° C., the drying property of the ink composition is lowered, so that the density unevenness of the image is noticeable and the fixing property of the image may be lowered.

  When the content of the alkyl polyol is less than 10% by mass, the nozzle of the inkjet recording head may be clogged due to an increase in the drying property of the ink composition. On the other hand, if it exceeds 25% by mass, the drying property of the ink composition is lowered, so that the density unevenness of the image is noticeable and the fixing property of the image may be lowered. In addition, it becomes difficult to adjust the viscosity of the ink composition to a range suitable for the ink jet recording method, and as a result, the discharge amount decreases and stable discharge properties cannot be obtained.

1.4. Glycol ethers The ink composition according to the present embodiment comprises glycol ethers having an HLB value calculated by the Davis method in the range of 5.0 to 8.0. The ink composition according to the present embodiment includes the glycol ethers satisfying the above-described HLB value range, so that the wettability / penetration speed can be controlled without being significantly affected by the recording medium type. As a result, a clear image with little density unevenness can be recorded on various recording media, in particular, non-ink-absorbing or low-absorbing recording media.

Here, the HLB value of the glycol ethers used in the present embodiment is a value for evaluating the hydrophilicity of the compound proposed by Davis et al., For example, the document “JT Davies and EK Rideal,“ It is a numerical value obtained by the Davis method defined in Interface Phenomena “2nd ed. Academic Press, New York 1963”, which is a value calculated by the following equation (1).
HLB value = 7 + Σ [1] + Σ [2] (1)
(However, [1] represents the number of hydrophilic groups and [2] represents the number of hydrophobic groups.)
Table 1 below exemplifies the number of representative hydrophilic groups and hydrophobic groups.

  The glycol ethers contained in the ink composition according to the present embodiment have an HLB value calculated by the Davis method in the range of 5.0 to 7.8, and in the range of 5.8 to 7.8. Preferably there is. When the HLB value is less than 5.0, the hydrophobicity of the glycol ethers increases, and the affinity with water as the main solvent may decrease and the storage stability of the ink may decrease. When the HLB value is greater than 8.0, the effect of wettability / penetration to the recording medium is reduced, and the density unevenness of the image may be noticeable. In particular, the wettability effect on a non-ink-absorbing or low-absorbing recording medium that is a hydrophobic surface tends to be significantly reduced.

  Specific examples of such glycol ethers include ethylene glycol monoisobutyl ether, ethylene glycol monohexyl ether, ethylene glycol monoisohexyl ether, diethylene glycol monohexyl ether, triethylene glycol monohexyl ether, diethylene glycol monoisohexyl ether, triethylene glycol Ethylene glycol monoisohexyl ether, ethylene glycol monoisoheptyl ether, diethylene glycol monoisoheptyl ether, triethylene glycol monoisoheptyl ether, ethylene glycol monooctyl ether, ethylene glycol monoisooctyl ether, diethylene glycol monoisooctyl ether, triethylene glycol Monoisooctylate , Ethylene glycol mono-2-ethylhexyl ether, diethylene glycol mono-2-ethylhexyl ether, triethylene glycol mono-2-ethylhexyl ether, diethylene glycol mono-2-ethylpentyl ether, ethylene glycol mono-2-ethylpentyl ether, ethylene glycol mono -2-methylpentyl ether, diethylene glycol mono-2-methylpentyl ether, propylene glycol monobutyl ether, dipropylene glycol monobutyl ether, tripropylene glycol monobutyl ether, propylene glycol monopropyl ether, dipropylene glycol monopropyl ether, tripropylene glycol monomethyl Examples include ether. These can be used individually by 1 type or in mixture of 2 or more types.

  Among the glycol ethers exemplified above, the alkyl group contained in the glycol ethers preferably has a branched structure. By containing a glycol ether having an alkyl group having a branched structure, it is possible to record a clear image with little shading unevenness, particularly on a non-ink-absorbing or low-absorbing recording medium. Specifically, ethylene glycol monoisobutyl ether, ethylene glycol monoisohexyl ether, diethylene glycol monoisohexyl ether, triethylene glycol monoisohexyl ether, ethylene glycol monoisoheptyl ether, diethylene glycol monoisoheptyl ether, triethylene glycol monoiso Heptyl ether, ethylene glycol monoisooctyl ether, diethylene glycol monoisooctyl ether, triethylene glycol monoisooctyl ether, ethylene glycol mono-2-ethylhexyl ether, diethylene glycol mono-2-ethylhexyl ether, triethylene glycol mono-2-ethylhexyl ether , Diethylene glycol mono-2-ethyl Inch ether, ethylene glycol mono-2-ethyl pentyl ether, ethylene glycol mono-2-methylpentyl ether, diethylene glycol mono-2-methylpentyl ether, and the like.

  Among the branched structures of the alkyl group contained in the glycol ethers, a 2-methylpentyl group, a 2-ethylpentyl group, and a 2-ethylhexyl group are more preferable, and a 2-ethylhexyl group is particularly preferable from the viewpoint of further improving color developability. preferable. Specifically, ethylene glycol mono-2-ethylhexyl ether, diethylene glycol mono-2-ethylhexyl ether, triethylene glycol mono-2-ethylhexyl ether, diethylene glycol mono-2-ethylpentyl ether, ethylene glycol mono-2-ethylpentyl ether , Ethylene glycol mono-2-methylpentyl ether, diethylene glycol mono-2-methylpentyl ether, etc., ethylene glycol mono-2-ethylhexyl ether, diethylene glycol mono-2-ethylhexyl ether, triethylene glycol mono-2-ethylhexyl ether Etc. are particularly preferred.

  The content of the glycol ethers improves the wettability and penetrability of the recording medium to reduce density unevenness, and improves the storage stability and ejection reliability of the ink. 0.05-6 mass% is preferable with respect to the total mass (100 mass%). When the content is 0.05% by mass or more, the wettability, penetrability, and drying properties of the ink composition are good, and a clear image is obtained, and the printing density (coloring property) is also good. . Further, when the content is 6% by mass or less, the ink has a low viscosity, excellent clogging stability of the head, and is completely dissolved in the ink composition, so that the storage stability is improved. Of the glycol ethers, those having poor water solubility are effective, and the content thereof is more preferably 0.1 to 2% by mass with respect to the total mass (100% by mass) of the ink composition.

  In addition, the alkyl polyols in the ink composition according to the present embodiment can be used in the ink vehicle of glycol ethers having an HLB value calculated by the Davis method in the range of 5.0 to 7.8. It has the property of a solubilizer.

1.5. Surfactant The ink composition according to the present embodiment may contain a surfactant. By containing a surfactant in the ink composition, an action of uniformly spreading on the recording medium is imparted. This makes it possible to record a clear image with little shading unevenness.

  The surfactant having such an effect is preferably a nonionic surfactant. Examples of such nonionic surfactants include, but are not limited to, acetylene glycol, silicone, polyoxyethylene alkyl ether, polyoxypropylene alkyl ether, polycyclic phenyl ether, sorbitan derivatives, and Fluorine-based surfactants can be used, and among them, at least one of acetylene glycol-based surfactant and silicone-based surfactant is preferable.

1.5.1. Acetylene glycol surfactants Acetylene glycol surfactants are superior to other nonionic surfactants in their ability to properly maintain surface tension and interfacial tension, and hardly cause foaming. . As a result, the ink containing the acetylene glycol surfactant can appropriately maintain the interfacial tension and the surface tension with the printer member in contact with the ink such as the nozzle surface of the head. Therefore, the ejection stability can be improved by using an ink containing an acetylene glycol surfactant in an ink jet recording system. Furthermore, by using it in combination with other surfactants that easily foam, it is possible to make it difficult to foam or to defoam the foam once generated. Furthermore, since the acetylene glycol-based surfactant exhibits good affinity (wetting property) and penetrability with respect to the recording medium, an image recorded using the ink composition containing the acetylene glycol-based surfactant has a high degree of bleeding. It will be fine.

  Although it does not specifically limit as acetylene glycol type surfactant, For example, Surfynol 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 (all are trade names, manufactured by Air Products Japan), Olphin 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, DF110D (all are trade names, manufactured by Nissin Chemical Industry Co., Ltd.), acetylenol E00, E00P, E40, E100 (all are products) Name, manufactured by Kawaken Fine Chemical Co., Ltd.).

  One acetylene glycol surfactant may be used alone, or two or more acetylene glycol surfactants may be used in combination.

  The content of the acetylene glycol surfactant is 0.1% by mass or more and 3% by mass because the storage stability and ejection stability of the ink are further improved with respect to the total mass (100% by mass) of the ink. % Or less, and more preferably 0.2% by mass or more and 1% by mass or less.

1.5.2. Silicone-based surfactant Silicone-based surfactants are superior to other nonionic surfactants in their ability to uniformly spread ink so as not to cause bleeding on the recording medium.

  Although it does not specifically limit as a silicone type surfactant, A polysiloxane type compound is mentioned preferably. Although it does not specifically limit as the said polysiloxane type compound, For example, polyether modified organosiloxane is mentioned. Examples of commercially available products of the polyether-modified organosiloxane include BYK-306, BYK-307, BYK-333, BYK-341, BYK-345, BYK-346, BYK-348, BYK-349 (above trade names, Manufactured by BYK), 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 name, manufactured by Shin-Etsu Chemical Co., Ltd.), Orphine PD-501, Olphine PD-502, Olphine PD-570 (above products) Name, manufactured by Nissin Chemical Industry Co., Ltd.).

A silicone type surfactant may be used individually by 1 type, and 2 or more types may be mixed and used for it.
The content of the silicone-based surfactant is such that the storage stability and ejection stability of the ink are further improved, so that the content is 0.01% by mass or more and 3% by mass with respect to the total mass (100% by mass) of the ink. It is preferable that it is the following ranges, More preferably, it is 0.05 mass% or more and 2 mass% or less.
Since the silicone-based surfactant easily foams, the use of the silicone-based surfactant in combination with the above-mentioned acetylene glycol-based surfactant can improve the defoaming of the ink.

1.6. Other Additives In addition to the constituents described above, the ink composition according to the present embodiment further improves the properties of the ink composition according to need, such as a penetrating solvent, a humectant, and an antiseptic / antifungal agent. , PH adjusting agents, chelating agents and the like can be added.

1.7. Water The ink composition of the present embodiment may contain water. In particular, when the ink is a water-based ink, water is a main medium of the ink, and becomes a component that evaporates and scatters when the recording medium is heated in ink jet recording.
Examples of water include water from which ionic impurities have been removed as much as possible, such as pure water such as ion exchange water, ultrafiltration water, reverse osmosis water, and distilled water, and ultrapure water. Further, when water sterilized by ultraviolet irradiation or addition of hydrogen peroxide is used, generation of mold and bacteria can be prevented when the pigment dispersion and ink using the same are stored for a long period of time.

1.8. Physical Properties of Ink Composition The pH of the ink composition is preferably neutral or alkaline, and more preferably in the range of 7.0 to 10.0. If the pH is acidic, the storage stability and dispersion stability of the ink composition may be impaired. In addition, problems such as corrosion of metal parts used in the ink flow path in the ink jet recording apparatus are likely to occur. The pH can be adjusted to neutral or alkaline using the pH adjusting agent described above.

The viscosity of the ink composition is preferably in the range of 1.5 mPa · s to 15 mPa · s at 20 ° C., more preferably 2.0 mPa · s to 10 mPa · s. Within this range, ink ejection stability can be ensured in the first step described later.
The surface tension of the ink composition is preferably 15 mN / m to 40 mN / m, and more preferably 20 mN / m to 30 mN / m at 25 ° C. Within this range, ink ejection stability can be ensured in the first step described later, and appropriate wettability with respect to a non-ink-absorbing or low-absorbing recording medium can be secured.

1.9. Method for Producing Ink Composition The ink composition according to the present embodiment can be obtained by mixing the materials described above 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 One embodiment of the present invention relates to an inkjet recording method (hereinafter also simply referred to as “recording method”). The recording method contains 10% by mass or more and 25% by mass or less of a coloring material, two or more kinds of resin particles having a heat distortion temperature of 40 ° C. or more, and two kinds of alkyl polyols having a boiling point of 190 ° C. or more and 250 ° C. or less. In addition, an ink composition having a boiling point of 220 ° C. or more and 250 ° C. or less at a pressure of 1 atm to 2% to 10% and substantially not containing a predetermined pyrrolidone derivative (hereinafter, “ Also referred to as “predetermined ink composition”).

  The recording method includes an image forming step of forming an image of a predetermined ink composition on a recording surface of a predetermined recording medium, and a heating step of heating the recording medium at 35 to 100 ° C. It is a waste.

  Hereinafter, an example of the recording method of the present embodiment will be described in detail for each process.

2.1. Image Forming Process The recording method of this embodiment includes an image forming process. In the image forming process, an ink, ie, an ink coating film is formed by ejecting and adhering (landing) a predetermined ink composition toward a non-ink-absorbing or low-absorbing recording medium by an ink jet method. Is.

  Any method can be used for the ink jet recording head as long as the ink composition is ejected as droplets from a fine nozzle and the droplets are attached to a recording medium. Examples of the ink jet recording head system include the following four systems.

The first method is called an electrostatic attraction method. A strong electric field is applied between a nozzle and an acceleration electrode placed in front of the nozzle, and ink is continuously ejected from the nozzle in the form of droplets. Is a method in which a print information signal is applied to the deflection electrode while it is flying between the deflection electrodes and recorded, or an ink droplet is ejected corresponding 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 thermal energy, and the ink liquid is heated and foamed with a microelectrode in accordance with a print information signal, and ink droplets are ejected and recorded.

  The viscosity of the predetermined ink composition to be ejected is preferably 1 to 8 mPa · s. If the viscosity of the ink is within the above range, the ejection stability is good, so the ink at the time of ejection need not be heated. The temperature of the ink during ejection is preferably 20 to 40 ° C. On the other hand, the ink may be discharged after the viscosity is within the above range by heating the ink at a predetermined temperature.

Speaking of the image forming conditions, that is, the printing conditions, the printing resolution can increase the printing speed, and can realize high-quality image formation without bleeding (bleeding) and aggregation unevenness, so that 360 dpi × 360 dpi to 2 , 880 dpi × 2,880 dpi. The formation speed of the image, i.e. printing speed, scratch resistance, coloring property, and is excellent in bleeding resistance, is preferably 0.3 m ² / min or more, 0.3~2.0m ² / min More preferably. The coating weight of the ink composition per unit area of at least a partial region of the image is excellent in coloring property, it is preferably 7 mg / inch ² or more, and more to be 7～30Mg / inch ² preferable.

  In the present specification, the “adhesion amount of the ink composition per unit area” may be the above-mentioned preferable range in at least a partial region of the image, and the average of the adhesion amount in any two places in the image. The value is preferably in the above preferable range, and the average value of the adhesion amount of the entire image is more preferably in the above preferable range.

Any recording medium may be used as desired. Among these, in the ink jet recording apparatus according to the present embodiment, a non-ink-absorbing or low-absorbing recording medium can be suitably used. In the present specification, “non-ink-absorbing and low-absorbing recording medium” means “recording in which the water absorption from the start of contact to 30 msec ^1/2 in the Bristow method is 10 mL / m ² or less. Medium ". 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 coated on a base material such as a plastic film or paper that is not surface-treated for ink jet printing (that is, not formed with an ink absorbing layer) is used. And those having a plastic film adhered thereto. Examples of the plastic here include polyvinyl chloride, polyethylene terephthalate, polycarbonate, polystyrene, polyurethane, polyethylene, and polypropylene. Examples of the recording medium having low ink absorption include printing paper such as art paper, coated paper, and matte paper.

2.2. Heating process The recording method of the present embodiment includes a heating process. In the heating step, a non-ink-absorbing and low-absorbing recording medium is heated at 35 to 100 ° C. In other words, this step dries the ink (image) ejected and adhered to the recording medium. By this step, the liquid medium contained in the ink discharged onto the recording medium is quickly evaporated and scattered, and a film is formed by the resin particles contained in the predetermined ink composition. As a result, a high-quality image excellent in abrasion resistance and bleed resistance in which the dried ink is firmly fixed (adhered) on the recording medium can be obtained in a short time.

  In the present specification, the heating temperature when heating the recording medium refers to the temperature of the recording medium, more specifically the recording surface thereof. The said heating temperature can be measured with the thermograph using infrared thermography apparatus H2640 / H2630 (made by NEC Avio infrared technology).

  Here, the recording medium to be heated includes any recording medium before, during and after a predetermined ink composition is ejected. More specifically, the above heating step is performed for the purpose of quickly drying and fixing the ink adhering to the recording medium. Therefore, as long as the above object can be achieved, the recording medium may be heated at least one of before, during, and after discharge.

  The heating before discharge is not limited to the following, but for example, a heating unit is provided on the upstream side in the transport direction, and the recording medium is heated in advance. In this case, the temperature of the recording surface of the recording medium when the ink adheres is preferably about 35 to 60 ° C.

  The heating during ejection is not limited to the following, but for example, a heating means is provided below the area where ink is ejected from the head toward the recording medium (on the opposite side of the recording medium as viewed from the conveyance surface). Ink ejection and landing (attachment) and heating of the recording medium may be performed simultaneously. Further, the recording medium may be heated by providing a heating means on the side opposite to the recording medium as viewed from the head (above the head).

  The heating after ejection is not limited to the following, but for example, heating means may be provided on the downstream side in the transport direction to heat the recording medium to which the ink has adhered.

  As a specific example of the heating means described so far, a platen heater is provided below the conveyance surface of the recording medium (opposite side of the recording medium when viewed from the conveyance surface), and recording is performed from the opposite side of the recording surface. A means for heating the medium, a heating chamber or a thermostatic chamber for storing the recording medium in the middle of conveyance, a means for heating the recording medium from various directions, and a heater above the conveyance surface of the recording medium are provided. And means for heating the recording medium from the recording surface side. In addition, the types of heaters including platen heaters, heating chambers, and thermostatic baths are not limited to the following, but examples include hot air heaters, hot air heaters, and infrared heaters.

  Moreover, if it says about heating conditions, heating temperature is 35-100 degreeC. When the heating temperature is 35 ° C. or higher, evaporation and scattering of the liquid medium in the ink can be effectively promoted, and the drying property (fast drying property) of the ink becomes excellent. On the other hand, when the heating temperature is 100 ° C. or lower, deformation of the non-ink-absorbing and low-absorbing recording medium can be prevented, or image shrinkage can be prevented during heating and cooling of the recording medium. Can do. Further, since the above effect is further increased, the lower limit of the heating temperature is preferably 40 ° C or higher, more preferably 60 ° C or higher, while the upper limit of the heating temperature is preferably 100 ° C or lower, more preferably 80 ° C. It is as follows.

  In the recording method of the present invention, a pyrrolidone derivative having a high boiling point such as 2-pyrrolidone (boiling point 245 ° C.) and having a boiling point of 240 ° C. or higher at 1 atm is substantially not contained. Therefore, even if the heating temperature is such that the recording medium is not deformed and the image is not shrunk, the predetermined ink composition is excellent in quick drying properties. As a result, the image has excellent abrasion resistance and bleed resistance. The heating time is not particularly limited as long as the predetermined ink composition is sufficiently dried. For example, the heating time is preferably 10 seconds to 2 minutes.

2.3. Background Image Forming Process The recording method according to the present embodiment is a process of (1) or (2) described below (hereinafter referred to as “ It is preferable to further include “step (1)” and “step (2)”.

  Hereinafter, in order to distinguish the term from the background image, the image formed by the above-described image forming process may be referred to as a “foreground image”.

  The step (1) is performed before the above-described image forming step, that is, the foreground image forming step, and the background ink composition is ejected and attached to the area of the recording medium to which the predetermined ink composition is attached. In this way, a background image is formed. When the step (1) is included in this embodiment, the recording method is performed in the order of the step (1), the foreground image forming step, and the heating step described above. In this case, the obtained recorded material is suitable for viewing the foreground image from the side on which the image is formed because the background image and the foreground image overlap in this order on the recording medium.

  In addition, when the step (1) is included in the present embodiment, it is more preferable that a heating step is further included between the step (1) and the foreground image forming step. This effectively prevents bleeding (bleeding) between the background image and the foreground image. Regarding the details of the step (1) and the heating step that can be further included, the matters described in the above-mentioned foreground image forming step and the above-described heating step can be applied. Note that the foreground image forming step and the image forming conditions in step (1) are determined independently of each other, and the heating conditions in the above heating step and further included heating steps are also determined independently of each other. It is what is done.

  On the other hand, the step (2) is performed after the above-described image forming step, that is, the foreground image forming step, and the background ink composition is discharged toward the area of the recording medium to which the predetermined ink composition is adhered. A background image is formed by adhering. When the step (2) is included in this embodiment, the recording method is performed in the order of the foreground image forming step, the step (2), and the heating step described above, or the foreground image forming step and the heating described above. It carries out in order of a process and the said process (2). In these cases, the recorded matter obtained is suitable for viewing the foreground image from the recording medium side because the foreground image and the background image overlap in this order on the recording medium. Therefore, the recording medium is transparent or translucent so that the foreground image can be viewed from the recording medium side.

  In addition, when the step (2) is included in the present embodiment, and the recording method is performed in the order of the foreground image forming step, the step (2), and the heating step described above, the foreground image forming step, It is more preferable to further include a heating step between the step (2). This effectively prevents bleeding (bleeding) between the foreground image and the background image. Regarding the details of the step (2) and the heating step that can be further included, the matters described in the above-described foreground image forming step and the above-described heating step can be applied, and thus the description thereof is omitted here. The foreground image forming step and the image forming conditions in step (2) are determined independently of each other, and the heating conditions in the above heating step and further included heating steps are also determined independently of each other. It is what is done.

  As described above, according to the present embodiment, when a predetermined ink composition is recorded on a non-ink-absorbing and low-absorbing recording medium, high-speed printing is achieved and the image has excellent abrasion resistance. Furthermore, it is possible to provide an ink jet recording method that is excellent in image bleeding resistance and ink storage stability. Furthermore, the heating temperature for the recording medium is a relatively low temperature of 35 to 100 ° C., and the total adhesion amount (total ejection amount) of ink per unit area is large due to the printing of the background image. Even if it is unavoidable, high-speed printing can be realized, and an ink jet recording method with excellent image quality can be provided.

2.4. Inkjet Recording Apparatus One embodiment of the present invention relates to an inkjet recording apparatus. The recording apparatus performs recording using the ink jet recording method of the above embodiment. Examples of the ink jet recording apparatus include a line printer and a serial printer. These are different printer systems. Briefly speaking, a line printer is provided with a line head having a length corresponding to the width of the recording medium, and the head is fixed without moving (almost), and printing is performed in one pass (single pass). Is to be done. On the other hand, a serial printer normally performs printing in two or more passes (multi-pass) while the head reciprocates (shuttle movement) in a direction orthogonal to the conveyance direction of the recording medium.

  Further, as an ink jet recording apparatus, a so-called lateral recording apparatus (hereinafter referred to as a lateral recording apparatus) that forms an image by a single recording operation by performing a plurality of scans with a head on a recording medium stationary on a platen equipped with a heating mechanism. "Lateral printer"). This lateral printer can print a large amount and at a higher speed than a serial printer. This is due to the fact that the drying time of the ink in the recorded matter obtained using the lateral printer is much shorter than that of the serial printer. Thus, in the present embodiment, any type of printer such as a line printer, a serial printer, or a lateral printer can be used.

3. Examples Hereinafter, the present invention will be described in detail by way of examples. However, the present invention is not limited to these examples.

3.1. Preparation of pigment dispersion 3.1.1. Black pigment dispersion 1
To the black ink compositions according to Examples 1 to 8 and Comparative Examples 1 to 8, the black pigment dispersion 1 containing the pigment dispersed with the particulate dispersion resin 1 was added. Hereinafter, the manufacturing method of the black pigment dispersion liquid 1 is shown concretely.

(1) Production of particulate dispersion resin 1 For the black pigment dispersion liquid 1, a pigment contained in the particulate dispersion resin 1 was used. In order to prepare the black pigment dispersion 1, first, a particulate dispersion resin 1 was produced using the following materials and methods.

In a reaction vessel, 20 parts of methyl ethyl ketone, 0.03 part of a polymerization chain transfer agent (2-mercaptoethanol), and as a monomer, component (a); methacrylic acid (trade name: GE-110 (MAA), Mitsubishi Gas Chemical Co., Ltd. 15 parts, (b) component; styrene macromer (trade name: AS-6S, number average molecular weight 6,000, 50% toluene solution, manufactured by Toagosei Co., Ltd.) 20 parts, (c) component; 2-ethylhexyl 30 parts of methacrylate (trade name: acrylate EH, manufactured by Mitsubishi Rayon Co., Ltd.), component (c); 30 parts of styrene monomer (trade name: styrene monomer, manufactured by Nippon Steel Chemical Co., Ltd.), and component (e): methoxypolyethylene glycol in monomethacrylate (the above equation (1), n is 9, R ¹ and R ³ is a methyl group, R ² is an ethylene group, trade name: K ester M-90G, while stirring mixed put by 10%, respectively of Shin-Nakamura Chemical Co., Ltd.) 15 parts, sufficiently purged with nitrogen gas to obtain a mixed solution.

  On the other hand, the remaining 90% of each of the above monomers was charged into a dropping funnel, and then 0.27 part of a polymerization chain transfer agent (2-mercaptoethanol), 60 parts of methyl ethyl ketone and 2,2′-azobis (2,4- 1.2 parts of (dimethylvaleronitrile) was added and mixed, and nitrogen gas substitution was sufficiently performed to obtain a mixed solution.

  Under a nitrogen atmosphere, the mixed solution in the reaction vessel was heated to 75 ° C. while stirring, and the mixed solution in the dropping funnel was gradually dropped into the reaction vessel over 3 hours. After completion of the dropwise addition, the liquid temperature of the mixed solution was maintained at 75 ° C. for 2 hours, and then a solution in which 0.3 part of 2,2′-azobis (2,4-dimethylvaleronitrile) was dissolved in 5 parts of methyl ethyl ketone was added, Further, aging was performed at 75 ° C. for 2 hours and at 85 ° C. for 2 hours to complete the reaction, and a solution containing the dispersion resin 1 was obtained. The solution containing the obtained dispersion resin 1 was dried under reduced pressure to produce a particulate dispersion resin 1. The resulting particulate dispersion resin 1 had a weight average molecular weight of 196,000.

(2) Preparation of Black Pigment Dispersion 1 When a pigment is added to the ink composition, the pigment is obtained in advance in the above “3.1.1. (1) Production of particulate dispersion resin 1”. In addition, a pigment dispersion liquid (pigment dispersion liquid composed of pigment contained in the particulate dispersion resin) dispersed in water with the particulate dispersion resin 1 was used. The pigment used has water-insoluble properties.

  Black pigment dispersion 1 was prepared as follows. First, 25 parts of the particulate dispersion resin 1 obtained above was dissolved in 70 parts of methyl ethyl ketone, and 4.1 parts of 5N sodium hydroxide aqueous solution (neutralization degree 75%) and 230 parts of ion-exchanged water were added. The polymer was neutralized and then dispersed using an ultradisper (manufactured by Asada Tekko Co., Ltd.) (disper blade, 2,000 revolutions / minute, 10 minutes). I. 90 parts of Pigment Black 7 was added, and further dispersed for 1 hour at 9,000 rpm at 15 ° C. or lower.

  The obtained dispersion was dispersed using Picomill (manufactured by Asada Tekko Co., Ltd., dispersion medium: zirconia, temperature: 20 ° C., dispersion medium: weight ratio of dispersion = 8: 2) (peripheral speed 15 m / second, 2 hours) ). The obtained dispersion was further dispersed with a microfluidizer (trade name, manufactured by Micro fluidics) (200 MPa, 10 passes). Next, 250 parts of ion-exchanged water was added to the obtained dispersion and stirred, and then immersed in a 60 ° C. water bath to remove methyl ethyl ketone under reduced pressure, and a part of water was further removed to obtain a solid content concentration. Of 20% (pigment solid content: 14%) was obtained.

  Next, 0.177 g of a crosslinking agent (trade name: Denacol EX321, epoxy equivalent 140, about 27 g (25 ° C.) dissolved in 100 g of water, manufactured by Nagase ChemteX Corporation) was added to 40 g of the obtained aqueous dispersion. Stirring was performed at 90 ° C. for 1 hour. After stirring, the mixture was cooled and filtered through a membrane filter having a pore size of 5 μm to obtain a black pigment dispersion 1 having a solid content concentration of 20% (pigment solid content: 14%).

In addition, the crosslinking rate in the black pigment dispersion liquid 1 was 40 mol%. Specifically, the crosslinking rate was calculated as follows.
Crosslinking rate: (0.177 / 140) × 100 / (1.6 × 0.17 / 86) = 40 (mol%)
Here, the amount of crosslinking agent used 0.177 g, epoxy equivalent 140, the amount of particulate dispersion resin 1 used 1.6 g, the proportion of structural units derived from methacrylic acid in particulate dispersion resin 1 0.17, methacrylic acid The molecular weight is 86.

Further, the amount of the anionic group neutralized with a base per 1 g of the crosslinked dispersed resin 1 was 1.34 mmol. The amount of anionic group was calculated as follows.
Amount of anionic group neutralized with base per gram of crosslinked dispersion resin 1: 111/56 × 0.75 × (1.6 / 1.777) = 1.34 (mmol)
Here, the acid value 111 of the dispersion resin 1 and the neutralization degree are 75%.
Moreover, the usage-amount of a crosslinking agent is an amount which reacts with 0.00126 / 1.6 * 1000 = 0.79 mmol in conversion of the amount of anionic group per 1g of polymers.
Further, the glass transition temperature (Tg) of the crosslinked dispersed resin 1 was 52 ° C. when measured with a thermal analyzer EXSTAR-6000 (manufactured by SII Nanotechnology Co., Ltd.) based on JIS K7121.

3.1.2. Preparation of Black Pigment Dispersion Liquid 2 In the black ink compositions according to Examples 9 to 15, pigment dispersed with Jonkrill 611 (trade name: manufactured by BASF Japan Ltd.), which is a styrene-acrylic acid dispersion resin. A black pigment dispersion 2 containing was added. Pigment dispersion 2 was prepared as follows.

  First, C.I. I. 70 parts of Pigment Black 7 was mixed with 30 parts of Johncril 611 (trade name: manufactured by BASF Japan Ltd.), 1.70 parts of potassium hydroxide, and 250 parts of ion-exchanged water. (Distributed media: Zirconia, manufactured by Asada Tekko Co., Ltd., temperature: 20 ° C., dispersed media: dispersion weight ratio = 8: 2) (peripheral speed 15 m / second, 2 hours). The obtained dispersion was further dispersed with a microfluidizer (trade name, manufactured by Micro fluidics) (200 MPa, 10 passes). The obtained aqueous dispersion was filtered through a membrane filter having a pore size of 5 μm to obtain a black pigment dispersion 2 having a solid content concentration of 20% (pigment solid content: 14%).

3.2. Preparation of Ink Composition Examples 1 to 15 and comparative examples having different material compositions in the material compositions shown in Tables 2 to 3 using the black pigment dispersion prepared in “3.1. Preparation of Pigment Dispersion” above. The black ink compositions of Examples 1-8 were prepared. For each ink composition, the materials shown in Table 2 are put 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 10 μm to remove impurities such as dust and coarse particles. It was prepared by.

Furthermore, a commercially available titanium dioxide pigment as a white color material (product name “NanoTek (R) Slurry” manufactured by CI Kasei Co., Ltd., a slurry white pigment containing titanium dioxide particles having an average particle diameter of 300 nm at a solid content concentration of 15%) The white ink composition of Example 16 was prepared by mixing and stirring the material components shown in Example 16 of Table 2 through a membrane filter having a pore size of 10 μm to remove impurities such as dust and coarse particles. Prepared.
The numerical values in Tables 2 to 3 all indicate mass%, and ion exchange water was added so that the total amount of ink was 100 mass%.

In Tables 2 and 3, the materials described by trade names are as follows.
・ Jonkrill 537 (BASF Japan Ltd., styrene-acrylic emulsion)
・ Jonkrill 538 (BASF Japan Ltd., styrene-acrylic emulsion)
・ Jonkrill 2570 (manufactured by BASF Japan Ltd., styrene-acrylic emulsion)
・ AQUACER 515 (manufactured by Big Chemie Japan KK, polyethylene wax emulsion (35% dispersion)) (melting point 135 ° C.)
・ BYK-348 (Bic Chemie Japan, silicone surfactant)
・ Orphine PD-570 (Nisshin Chemical Co., Ltd., silicone surfactant)
・ Surfinol DF110D (Nisshin Chemical Co., Ltd., acetylene glycol surfactant)

3.3. Evaluation of ink composition 3.3.1. Storage Stability of Ink Composition Each of the ink compositions of Examples 1 to 15 and Comparative Examples 1 to 8 shown in Tables 2 to 3 was sealed in a sample bottle and left in a 60 ° C. environment for 2 weeks. . The storage stability of the ink composition was evaluated by observing changes in the viscosity of the ink composition after standing and the separation, sedimentation, and aggregation of the ink components. The evaluation results are shown in Table 4. The evaluation criteria are as follows.

<Viscosity change>
A: Change rate is less than ± 5% compared to the viscosity immediately after preparation.
B: Change rate is ± 5% or more and less than ± 10% compared to the viscosity immediately after preparation.
C: Change rate is ± 10% or more and less than ± 20% compared to the viscosity immediately after preparation.
D: The rate of change is ± 20% or more compared to the viscosity immediately after preparation.
<Separation, sedimentation, and aggregation of ink components>
A: There is no separation / sedimentation / aggregation of ink components.
B: Any of separation, sedimentation, and aggregation of ink components is slightly observed.
C: Any of ink component separation / sedimentation / aggregation is clearly seen.
D: Any of ink component separation / sedimentation / aggregation is remarkable.

3.3.2. Ink-jet head clogging property of ink composition Each ink composition of Examples 1 to 15 and Comparative Examples 1 to 8 shown in Tables 2 and 3 was replaced with SurePress L-4033A (trade name, Seiko Epson Co., Ltd.). Briefly speaking, this printer (printer) includes a piezo head that ejects ink droplets, and a platen heater provided below a region where ink is ejected from the head toward a recording medium. And a drying furnace provided downstream of the platen heater in the transport direction.

  Each ink composition shown in Table 2 and Table 3 was filled in the head of SurePress L-4033A. After filling, print a nozzle check pattern to confirm that there is no filling failure or nozzle clogging, then turn off the printer and return the head to the home position (ie, capped on the head). And left in an environment of 40 ° C./10-20% RH for 20 days. After leaving, a cleaning operation was performed as necessary, a nozzle check pattern was printed, and the discharge state of the nozzle was observed to evaluate the clogging of the ink jet head of the ink composition. The evaluation criteria are shown below, and the evaluation results are shown in Table 5.

A: The ink composition was normally discharged from all nozzles within 3 cleaning operations.
B: The ink composition was normally ejected from all nozzles within the range of 4 to 6 cleaning operations.
C: The ink composition was normally ejected from all nozzles within the range of 7 to 10 cleaning operations.
D: The cleaning operation was required 11 to 15 times until the ink composition was normally discharged from all the nozzles.
E: Some nozzles were not ejected normally even after 15 or more cleaning operations.

3.3.3. Measurement of Print Density of Printed Material 55PW8R (trade name, manufactured by Lintec Corporation), which is a high-quality paper that absorbs ink well, was used as a recording medium.

  Ink digital label printer SurePress L-4033A (trade name, manufactured by Seiko Epson Corporation) was filled with the ink compositions of Examples 1 to 15 and Comparative Examples 1 to 8, and printed on the recording medium. As a print pattern, a fill pattern that can be printed with a resolution of 720 dpi horizontal and 720 dpi vertical and 100% duty was used. As the printing condition, the heater setting of the printer was set to “setting at which the temperature of the printing surface is 45 ° C.”. Furthermore, the drying process was performed by blowing the wind of the temperature of 75 degreeC with respect to the printed matter during printing and immediately after printing. The air blowing intensity indicates a state in which wind is sent so that the wind speed on the surface of the recording medium is about 2 m / sec to 5 m / sec. Moreover, the ventilation time immediately after printing was 1 minute.

The print density (OD value) of the printed material when printed under such conditions was measured. For the measurement, a portable reflection densitometer RD-19T (trade name, manufactured by Sakata Inx Engineering Co., Ltd.) was used. The results are shown in Table 6. The evaluation criteria for the print density of the printed matter are as follows.
A: O.I. D. The value is 1.4 or more.
B: O.D. D. The value is 1.3 or more and less than 1.4.
C: O.I. D. The value is 1.2 or more and less than 1.3.
D: O.D. D. The value is less than 1.2.

3.3.4. Evaluation of density unevenness of printed matter 55PW8R (trade name, manufactured by Lintec Corporation), which is a high-quality paper that absorbs ink well as a recording medium, and SY51M 2.6 mil., Which is a non-ink-absorbing polypropylene film. PPWhite TC RP37 2.2 mil. HIGH DENSITY WHITE (trade name, manufactured by UPM RAFLATAC, hereinafter abbreviated as “SY51M”) was used.

  Ink digital label printer SurePress L-4033A (trade name, manufactured by Seiko Epson Corporation) was filled with the ink compositions of Examples 1 to 15 and Comparative Examples 1 to 8, and printed on the recording medium. As the print pattern, a fill pattern that can be printed at a resolution of 720 dpi in the horizontal direction and 720 dpi in the vertical direction with a duty in the range of 50% to 100% in 10% increments was used. Other printing conditions were the same as in “3.3.3 Printing density measurement of printed matter”.

The density unevenness of the printed material when printed under such conditions was visually confirmed. The results are shown in Table 7. In addition, the evaluation criteria for the uneven density of the printed matter are as follows.
A: Uneven density was not observed even at a duty of 80% or more.
B: No uneven density was observed up to a duty of 70%.
C: Density unevenness was not observed up to a duty of 60%.
D: Density unevenness was observed even at a duty of 60% or less.

3.3.5. Evaluation of abrasion resistance of printed matter This evaluation was performed in a laboratory under room temperature (25 ° C.) conditions.
Ink digital label printer SurePress L-4033A (trade name, manufactured by Seiko Epson Corporation) was filled with the ink compositions of Examples 1 to 15 and Comparative Examples 1 to 8, and printed on the recording medium. As a print pattern, a fill pattern that can be printed with a resolution of 720 dpi horizontal and 720 dpi vertical and 100% duty was used. This evaluation was performed in a laboratory at room temperature (25 ° C.). Other printing conditions were the same as in “3.3.3 Printing density measurement of printed matter”.

Thereafter, the printed surface of the printed matter left for 5 hours in a laboratory at room temperature (25 ° C.) was subjected to a load of 200 g using a Gakushin friction fastness tester AB-301 (trade name, manufactured by Tester Sangyo Co., Ltd.). The rubbing resistance was evaluated by confirming the peeled state of the printed surface and the state of ink transfer to the cotton cloth when rubbed 20 times with the lower / cotton cloth. The evaluation criteria for abrasion resistance are as follows. The results are shown in Table 8.
A: Ink peeling and ink transfer to a cotton cloth were not observed even after rubbing 20 times.
B: After rubbing 20 times, ink peeling or ink transfer to a cotton cloth was slightly observed.
C: After rubbing 20 times, ink peeling or ink transfer to a cotton cloth was observed.
D: Ink peeling or ink transfer to cotton cloth was observed before rubbing 20 times.

3.3.6. Overprint printing evaluation 1 (white → black)
Inkjet recording (overcoat printing) was added to which a process for forming a background image was added. As the background ink, the white ink composition of Example 16 prepared in the above “3.2. Preparation of ink composition” was used.

First, from the piezo head of SurePress L-4033A, the white ink composition of Example 16 was ejected and adhered to the PP film (SY51M) heated to 45 ° C. by the platen heater, and a white background solid was obtained. A pattern image (background image) was formed. Subsequently, the black ink pattern of Example 1 was ejected and adhered from another piezo head of SurePress L-4033A toward the white solid pattern image, and a black solid pattern image (black image) was formed. Overlaid (the white image formation and the black image formation were performed in 8 passes each, so a total of 16 passes were printed). The printing conditions at this time were a printing resolution of 1440 dpi × 720 dpi, an ink adhesion amount per unit area of 10 mg / inch ² , and an image formation speed (printing speed) of 0.934 m ² / min.
Thereafter, the solid pattern image was heated in a drying furnace. The image forming conditions and heating conditions at this time are the same as those employed in Example 1.

In this way, a recorded material was produced in which a background image and a black image were overlaid in this order on the film. The obtained recorded matter was evaluated for abrasion resistance in the same manner as in Example 1.
Next, the image was changed to an image in which white characters were arranged in the solid pattern image, and the visibility of white characters in the obtained recorded matter was visually observed. The evaluation criteria are as follows.
A: The 8-point white letters are clearly visible.
B: The bleeding of 8-point white characters is severely invisible as characters.
As a result, the rub resistance was “A” and the bleed resistance was “A”.

  As a comparative experiment, a recorded matter was produced in the same manner as described above except that the ink of Comparative Example 2 was used as the black ink composition. Scratch resistance and bleed resistance were evaluated. As a result, the rub resistance was “D” and the bleed resistance was “B”.

3.3.7. Overprint printing evaluation 2 (black → white)
A recorded matter was produced in the same manner as in Example 9 except that a black solid pattern image was formed and heated, and then a white background solid pattern image was formed and heated. The evaluation results are shown below. As a result, the rub resistance was “A” and the bleed resistance was “A”.

  As a comparative experiment, a recorded matter was produced in the same manner as described above except that the ink of Comparative Example 2 was used as the black ink composition. Scratch resistance and bleed resistance were evaluated. As a result, the rub resistance was “D” and the bleed resistance was “B”.

  The present invention is not limited to the above-described embodiments, and various modifications can be made. For example, the present invention includes substantially the same configuration (for example, a configuration having the same function, method and result, or a configuration having the same purpose and effect) as the configuration described in the embodiment. In addition, the invention includes a configuration in which a non-essential part of the configuration described in the embodiment is replaced. In addition, the present invention includes a configuration that achieves the same effect as the configuration described in the embodiment or a configuration that can achieve the same object. In addition, the invention includes a configuration in which a known technique is added to the configuration described in the embodiment.

Claims (8)

10% by weight or more and 25% by weight of a coloring material, two or more kinds of resin particles having a heat distortion temperature of 40 ° C. or more, and two or more kinds of alkyl polyols having a boiling point of 190 ° C. or more and 250 ° C. or less corresponding to 1 atm. The content of the alkyl polyol having a boiling point of 220 ° C. or more and 250 ° C. or less is 2% or more and 10% or less and the boiling point is 240 ° C.
An image forming step of forming an image by ejecting and adhering the ink composition substantially free of the above pyrrolidone derivative toward a recording medium, and a heating step of heating the recording medium at 35 to 100 ° C. And an ink jet recording method. The ink jet recording method according to claim 1, wherein the ink composition contains substantially no resin having a glass transition temperature of 10 ° C. or lower. 3. The ink jet recording method according to claim 1, wherein the ink composition does not substantially contain an alkyl polyol having a boiling point of 280 ° C. or higher at 1 atm. 3. 4. The recording medium according to claim 1, wherein the recording medium is a non-ink-absorbing or low-absorbing recording medium, and an image recording speed on the recording medium is 0.3 m ² / min or more. The inkjet recording method as described. The inkjet recording method according to claim 1, further comprising the following step (1) or (2).
(1) A step of forming a background image by discharging and adhering a background ink composition toward an area of a recording medium to which the ink composition is attached, which is performed before the image forming step.
(2) A step of forming a background image by discharging and adhering the background ink composition toward an area of the recording medium to which the ink composition is adhered, which is performed after the image forming step. The inkjet recording method according to claim 1, wherein an adhesion amount of the ink composition per unit area in at least a partial region of the image is 10 mg / inch ² or more. The ink jet recording method according to claim 1, wherein the ink composition does not substantially contain a pyrrolidone derivative. An inkjet recording apparatus that performs recording using the inkjet recording method according to claim 1.