JP5915885B2 - Ink set, and ink jet recording apparatus and recorded matter using the same - Google Patents

Description

  The present invention relates to an ink set, an ink jet recording apparatus using the ink set, and a recorded matter.

  Conventionally, a printing method using an ink jet recording method is performed by causing ink droplets to fly and adhere (land) on a recording medium such as paper. Due to recent advances in ink-jet recording technology, printing methods using ink-jet recording are also being used in the field of high-definition image recording (image printing), which previously used photographs and offset printing. . In particular, various proposals have been made regarding inks capable of printing high-quality images on non-ink-absorbing and low-absorbing recording media.

  For example, Patent Document 1 describes: a) carbon black having a pH measured in accordance with JIS K 6221 of 6.0 or more and 8.0 or less, b) a polymer dispersant having an acid value of less than 50 mgKOH / g, c) amine Water-soluble resin or water-dispersible resin fine particles having an acidic group neutralized by d), one or more water-soluble organic solvents selected from d) glycol ethers and 1,2-alkanediols having 4 or more carbon atoms, and e) a water-based ink-jet ink containing water, and an ink-jet recording method using the ink to record by heating the surface temperature of the non-water-absorbing recording medium to 40 ° C. or more and 80 ° C. or less. (Paragraphs 0011, 0018, 0019, and 0023 in the specification of Document 1).

  For example, Patent Document 2 discloses a non-water-absorbing recording medium having a surface tension in a range of 25 mN / m to 35 mN / m and containing a hydrophobic organic solvent 1, a pigment, a polymer, and water. An inkjet ink and an inkjet recording method in which the surface temperature of a non-water-absorbable recording medium is heated to 35 ° C. or more and 80 ° C. or less using the ink are disclosed (see Reference 2). Paragraphs 0010, 0016, 0022) of the description.

JP 2011-074336 A JP 2009-120893 A

  However, in the case of water-based ink recorded on a non-ink-absorbing and low-absorbing recording medium, a drying step is required after recording for the purpose of moisture drying. For this reason, the environmental temperature in the recording apparatus increases, and the environmental temperature during ink ejection also increases. As a result, the ink in the vicinity of the nozzle is liable to dry and solidify, resulting in a problem that the intermittent printing characteristics are deteriorated. In addition, when an attempt is made to suppress drying due to the composition of the ink, there is a problem that the drying efficiency of the recorded matter is lowered, and the quality of the ink coating film, particularly the rub resistance of the recorded matter (image) is significantly deteriorated.

  Therefore, the present invention has an object to provide an ink set having excellent rub resistance and intermittent printing characteristics of a recorded matter, an ink jet recording apparatus using the ink set, and a recorded matter recorded using the ink set. One of them.

  The present inventors have intensively studied to solve the above problems. As a result, the above-described problem is caused by an ink set that includes the first ink and the second ink having a predetermined composition and that satisfies a predetermined condition between the humectants included in the first ink and the second ink. The present invention has been completed.

That is, the present invention is as follows.
[1]
A first ink containing water, a pigment , resin particles, a first humectant, and an aprotic polar solvent, and containing no alkyl polyol having a boiling point of 280 ° C. or higher with respect to the total mass of the ink of 1.0% by mass or more ,
Water, wherein the amount of the pigment exceeds the amount of the pigment first contained in the ink, wherein the resin particles in an amount less than the content of the resin particles contained in the first ink, the second humectant, and the non A second ink that contains a protic polar solvent and does not contain 1.0 mass% or more of an alkyl polyol having a boiling point of 280 ° C. or higher with respect to the total mass of the ink;
Including, and
It meets the following conditions (A) or (B),
The aprotic polar solvent is at least one selected from the group consisting of pyrrolidones, lactones, sulfoxides, imidazolidinones, sulfolanes, urea derivatives, dialkylamides, cyclic ethers, and amide ethers. Including ink set.
(A) the first humectant, (a1) 1,2-hexanediol and solvent der other than the 1,2-hexanediol is, the boiling point of the solvent other than the 1,2-hexanediol is 200 ° C. or higher and at 260 ° C. or less, and a boiling point of the first humectant all SANYO above the boiling point of the second humectant,
The second humectant is (a3) 1,2-hexanediol and a solvent other than the 1,2-hexanediol, and the boiling point of the solvent other than the 1,2-hexanediol is 160 ° C. or higher and 240 ° C. And
Of the first humectant, the solvent other than the 1,2-hexanediol and the second humectant other than the 1,2-hexanediol are glycol ether, polyalkylene glycol, and 1, α-alkane, respectively. One or more selected from diols (except α = 2), ethylene glycol and propylene glycol.
(B) The first moisturizing agent and the second moisturizing agent are 1,2-hexanediol and dipropylene glycol, and the content of dipropylene glycol contained in the first ink is the dihydric acid contained in the second ink. It exceeds the content of propylene glycol.
[ 2 ]
The ink set according to [ 1 ], wherein the second humectant is 1,2-hexanediol, and one or more glycol ethers selected from glycol ether and polyalkylene glycol .
[ 3 ]
The ink set according to [1] or [2] , wherein the boiling point of the aprotic polar solvent is 200 ° C. or higher and 260 ° C. or lower.
[ 4 ]
Prior Symbol first ink, and the total content of the solvent other than the 1,2-hexanediol and the 1,2-hexanediol, and the content of the aprotic polar solvent, the mass ratio of 0. The ink set according to any one of [1] to [ 3 ], which is 6 to 2.6.
[ 5 ]
The ink set according to any one of [1] to [ 4 ], wherein the resin particles are at least one of polyolefin wax and paraffin wax.
[ 6 ]
An inkjet recording apparatus that records using the ink set according to any one of [1] to [ 5 ].
[ 7 ]
Recorded matter recorded using the ink set according to any one of [1] to [ 5 ].

  Hereinafter, embodiments for carrying out the present invention will be described in detail. In addition, this invention is not restrict | limited to the following embodiment, A various deformation | transformation can be implemented within the range of the summary.

  In the present specification, the “boiling point” means a boiling point corresponding to 1 atm.

[Ink set]
An ink set according to an embodiment of the present invention includes a first ink and a second ink having a predetermined composition, and satisfies any one of predetermined (A) and (B) described later. is there.

  The first ink contains a color material, resin particles, a first humectant, and an aprotic polar solvent.

  The second ink includes a coloring material in an amount exceeding the content of the coloring material contained in the first ink, a resin particle in an amount less than the content of the resin particles contained in the first ink, a second humectant, and Contains an aprotic polar solvent.

  On the other hand, both the first ink and the second ink substantially contain no alkyl polyol having a boiling point of 280 ° C. or higher. Thereby, the load of a drying process can be reduced.

  Here, “substantially not containing” means not containing, for example, 1.0% by mass or more, preferably 0.5% by mass or more, with respect to the total mass (100% by mass) of the ink. More preferably 0.1% by mass or less, more preferably 0.05% by mass or less, and even more preferably 0.01% by mass or less. The most preferable content is 0.001% by mass or less.

  The ink set of the present embodiment is preferably composed of the first ink and the second ink, but in addition to the first ink and the second ink, the ink set further includes another ink different from these inks. But you can. In addition to the first ink and the second ink, when other ink different from these inks is further included, the other ink may contain an alkyl polyol having a boiling point of 280 ° C. or higher.

  Hereinafter, additives (components) contained in or included in each ink (ink composition) constituting the ink set of the present embodiment will be described.

  Hereinafter, when the ink further includes the first ink, the second ink, and other inks different from these inks, the other inks may be collectively referred to as “ink”. .

Unless otherwise specified, each component contained in the first ink and each component contained in the second ink are selected independently from each other in terms of type, physical properties, content, and the like. Further, not only when the first ink and the second ink included in one ink set are each composed of a single type, but also when there are a plurality of types of the first ink and a plurality of types of the second ink. Similarly to the above, the type of each component contained in each ink, its physical properties, the content, and the like are selected independently of each other.
Further, when there are a plurality of types of first inks included in one ink set, the “content of the first ink” means an average value of the contents in the respective first inks. The same applies when there are a plurality of types of second ink.

[Humectant]
Both the first ink and the second ink included in the ink set of the present embodiment contain a humectant. Here, “first humectant” in the present specification means a humectant contained in the first ink, and “second humectant” in the present specification means a humectant contained in the second ink. . The first humectant and the second humectant have a correlation that satisfies either of the conditions (A) or (B). Below, it demonstrates for every conditions of (A) and (B).

  First, the condition (A) will be described. In (A), the first humectant is (a1) 1,2-alkanediol and a solvent other than 1,2-alkanediol, or (a2) other than 1,2-alkanediol. It is a solvent. In addition, the boiling point of the solvent other than the 1,2-alkanediol in the first humectant is 200 ° C. or more and 260 ° C. or less. That is, the first humectant essentially includes a solvent other than 1,2-alkanediol having a predetermined boiling point regardless of whether or not it contains 1,2-alkanediol.

  When the boiling point of the first humectant is 160 ° C. or higher, the intermittent printing characteristics are excellent. On the other hand, when the boiling point of the first humectant is 260 ° C. or less, glycerin or the like is not added, so that quick drying is good and the recorded material has excellent abrasion resistance.

  The solvent other than the 1,2-alkanediol as the first humectant is not particularly limited as long as the boiling point is 200 ° C. or higher and 260 ° C. or lower. For example, glycol ethers, 1, α-alkanediol (however, , Α = 2 is excluded).

  Examples of the glycol ethers include, but are not limited to, polyalkylene glycols such as diethylene glycol, dipropylene glycol, and dibutylene glycol. The 1, α-alkanediol (excluding α = 2) is not limited to the following, but examples include 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, , 7-heptanediol. The alkylene glycol monoether contained in the polyalkylene glycols includes ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monoisopropyl ether, ethylene glycol monobutyl ether, ethylene glycol monohexyl ether, ethylene glycol monophenyl ether, diethylene glycol Monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, triethylene glycol monobutyl ether, tetraethylene glycol Monomethyl ether, tetraethylene glycol monoethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, dipropylene glycol monomethyl ether, and dipropylene glycol monoethyl ether and the like. Examples of the alkylene glycol diether contained in the polyalkylene glycols include ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dibutyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol dibutyl ether, triethylene glycol dimethyl ether, and triethylene glycol diethyl ether. , Triethylene glycol dibutyl ether, tetraethylene glycol dimethyl ether, tetraethylene glycol diethyl ether, tetraethylene glycol dibutyl ether, propylene glycol dimethyl ether, propylene glycol diethyl ether, dipropylene glycol dimethyl ether, and Dipropylene glycol diethyl ether. Among the glycol ethers, polyalkylene glycols are preferable because they have excellent moisture retention.

  Among these, at least one selected from glycol ethers and 1, α-alkanediol (except α = 2) is preferable because appropriate moisture retention can be imparted.

  When the first humectant is (a1) 1,2-alkanediol and a solvent other than the 1,2-alkanediol, in the first ink, the total content of the first humectant and the aprotic described later The mass ratio to the content of the polar solvent (“total content of the first humectant”: “content of the aprotic polar solvent”) is preferably 0.6 to 2.6. When the mass ratio is within the above range, the adhesiveness is excellent.

  In (A) above, the condition that the boiling point of the first humectant exceeds the boiling point of the second humectant is also satisfied. In the present specification, the “boiling point of the first humectant” means an average value of boiling points of the two or more solvents when the first humectant is composed of two or more solvents. The same applies to the “boiling point of the humectant”.

  Assuming that the condition is satisfied, the second humectant is (a3) 1,2-alkanediol and a solvent other than 1,2-alkanediol, or (a4) the 1,2-alkane. Solvent other than diol. In addition, the boiling point of the solvent other than the 1,2-alkanediol in the second humectant is preferably 160 ° C. or higher and 240 ° C. or lower. That is, the second moisturizing agent may be 1,2-alkanediol, but whether or not it contains 1,2-alkanediol, other than 1,2-alkanediol having a predetermined boiling point. It is preferable to include a solvent.

  When the boiling point of the second humectant is 160 ° C. or higher, the intermittent printing characteristics are excellent. On the other hand, when the boiling point of the second humectant is 240 ° C. or less, the drying load can be effectively reduced.

  The solvent other than the above-described 1,2-alkanediol as the second humectant is not particularly limited as long as the boiling point is 160 ° C. or higher and 240 ° C. or lower and lower than the boiling point of the first humectant. Since it is excellent, glycol ethers are preferable.

  Next, the condition (B) will be described. The first humectant and the second humectant are both dipropylene glycol. In addition, the content of dipropylene glycol contained in the first ink exceeds the content of dipropylene glycol contained in the second ink.

  The content of dipropylene glycol contained in the first ink is preferably 3 to 30% by mass and more preferably 5 to 15% by mass with respect to the total mass (100% by mass) of the first ink. On the other hand, the content of dipropylene glycol contained in the second ink is preferably 3 to 30% by mass, and more preferably 5 to 15% by mass. When each content of dipropylene glycol contained in the first ink and the second ink is within the above range, the drying load can be effectively reduced.

  In addition, when the ink set of the present embodiment further includes another ink different from the first ink and the second ink, the other ink may contain the above-described moisturizing agent.

[Color material]
The first ink and the second ink included in the ink set of the present embodiment contain a color material. The color material is selected from pigments and dyes.

(1. Pigment)
Of the above color materials, the pigment is not only insoluble or hardly soluble in water, but also has a property of hardly fading to light or gas. Therefore, a recorded matter recorded with an ink using a pigment has good water resistance, gas resistance, light resistance, and storage stability.
As the pigment, any of inorganic pigments and organic pigments can be used. Among these, at least one of carbon black and organic pigments belonging to the inorganic pigment is preferable because it has good color developability and is difficult to settle during dispersion because of its low specific gravity.

  Although it does not specifically limit as an inorganic pigment, For example, carbon black, iron oxide, and a titanium oxide 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, manufactured by Degussa AG), CONDUCTEX SC, Raven 1255, 5750, 5250, 5000, 3500, 1255, 700 (all trade names, Columbia Carbon ( Columbian Carbon Japan Ltd), Regal 400R, 330R, 660R, Mogul L, Monarch 700, 800, 880, 900, 1000, 1100, 1300, 1400, Elftex 12 (all trade names, Cabot Corporation) Manufactured).

  The organic pigment is not particularly limited. 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.

  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.

  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.

  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.

  A pigment may be used individually by 1 type and may be used in combination of 2 or more type.

(2. Dye)
Although it does not limit to the following as a dye among the said color materials, For example, an acidic dye, a direct dye, a reactive dye, and a basic dye are mentioned. Specific examples of the dye include 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.

  A dye may be used individually by 1 type and may be used in combination of 2 or more type.

The content of the color material contained in the second ink is greater than the content of the color material contained in the first ink. The first ink and the second ink can be referred to as light ink and dark ink, respectively, from the viewpoint of the amount of the color material.
The content of the color material contained in the first ink is preferably 1 to 7% by mass with respect to the total mass (100% by mass) of the first ink. In addition, the content of the color material contained in the second ink is preferably 0.1 to 2% by mass with respect to the total mass (100% by mass) of the second ink.

  In addition, when the ink set of the present embodiment further includes another ink different from the first ink and the second ink, the other ink may contain the above-described color material.

[Resin particles]
The first ink and the second ink included in the ink set of the present embodiment contain resin particles. When the first ink and the second ink contain resin particles, the recorded article has excellent abrasion resistance.

  Further, the content of the resin particles contained in the second ink is smaller than the content of the resin particles contained in the first ink. Thereby, the viscosity of each ink which comprises an ink set can be equalized. Each content of the resin particles contained in the first ink and the second ink will be described later.

  Examples of the resin particles include, but are not limited to, binder resins and waxes such as paraffin wax and polyolefin wax.

(1. Binder resin)
The above binder resin has an effect of improving the abrasion resistance of the recorded matter by sufficiently fixing the ink onto the recording medium by forming a resin film when the recording medium is heated in ink jet recording. To do. Therefore, the binder resin is preferably a thermoplastic resin. Due to the effects described above, a recorded matter recorded using an ink containing a binder resin is more excellent in abrasion resistance on a non-ink-absorbing and low-absorbing recording medium.

  The binder resin is contained in the ink in an emulsion state. By including the binder resin in the ink in an emulsion state, the viscosity of the ink can be easily adjusted to an appropriate range in the ink jet recording system, and the storage stability and ejection stability of the ink are excellent.

  In the present specification, “ejection stability” refers to a property of ejecting a stable ink droplet from the nozzle without clogging of the nozzle.

Examples of the binder resin include, but are not limited to, (meth) acrylic acid, (meth) acrylic 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.
In the present specification, “(meth) acryl” means at least one of acrylic and methacryl corresponding thereto.

  As said binder resin, what is obtained by a well-known material and a manufacturing method may be used, and a commercial item may be used. The commercially available products are not limited to the following, but include, for example, Microgel E-1002, Microgel E-5002 (trade names, manufactured by Nippon Paint Co., Ltd.), Boncourt 4001, Boncourt 5454 ( Product name, manufactured by DIC, SAE1014 (trade name, manufactured by Zeon Corporation), Cybinol SK-200 (trade name, manufactured by SAIDEN CHEMICAL INDUSTRY CO., LTD.), Jonkrill 7100, John Crill 390, John Crill 711, John Crill 511, John Crill 7001, John Crill 632, John Crill 741, John Crill 450, John Crill 840, John Crill 74J, John Crill HRC-1645J, John Crill 734, John Crill 852, Jongkrill 7600, Jongkuri 775, John Crill 537J, John Crill 1535, John Crill PDX-7630A, John Crill 352J, John Crill 352D, John Crill PDX-7145, John Crill 538J, John Crill 7640, John Crill 7641, John Crill 631, John Crill 790 , Jonkrill 780, Jonkrill 7610 (trade name, manufactured by BASF) and the like.

  Although said binder resin is not specifically limited, For example, it can obtain by the preparation method shown below, You may combine a some method as needed. As the preparation method, a polymerization catalyst (polymerization initiator) and a dispersant are mixed in a monomer of a component constituting a desired resin, and polymerization (emulsion polymerization) is performed. A resin having a hydrophilic portion is dissolved in water. A method of removing a water-soluble organic solvent by distillation after mixing a solution obtained by dissolving in a water-soluble organic solvent into water, and a solution obtained by dissolving a resin in a water-insoluble organic solvent together with a dispersant in an aqueous solution The method of mixing is mentioned.

  The dispersant that can be used when dispersing the binder resin in the emulsion state is not particularly limited, but examples include anions such as sodium dodecylbenzenesulfonate, sodium lauryl phosphate, and polyoxyethylene alkyl ether sulfate ammonium salt. And nonionic surfactants such as polyoxyethylene alkyl ethers, polyoxyethylene alkyl esters, polyoxyethylene sorbitan fatty acid esters, and polyoxyethylene alkylphenyl ethers. These dispersants may be used alone or in combination of two or more.

The average particle size of the binder resin is preferably in the range of 5 nm to 400 nm, and 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.
Here, the average particle diameter in this specification shall be shown by the value measured by the dynamic light scattering method.

  The content of the binder resin that can be contained in each ink (in terms of solid content) is preferably in the range of 0.5 to 5% by mass with respect to the total mass (100% by mass) of the ink, and is preferably 0.5 to 1.5%. A range of mass% is more preferred. When the content is within the above range, the abrasion resistance is further improved.

(2. Paraffin wax)
When the ink in the present embodiment contains paraffin wax, slip performance is imparted to the recorded matter, whereby the ink is further excellent in 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 in the present embodiment contains paraffin wax in an emulsion state, it is easy to adjust the viscosity of the ink 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 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 recorded material. On the other hand, the lower limit of the melting point of the paraffin wax 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 diameter of the paraffin wax 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 to further improve the storage stability and ejection stability of the ink. It is a range. A commercially available product may be used as it is as the paraffin wax. Examples of the commercially available products include, but are not limited to, AQUACER 537, AQUACER 539 (trade names, manufactured by BYK).

  The content (in terms of solid content) of the paraffin wax that can be contained in each ink is preferably in the range of 0 to 1.5% by mass with respect to the total mass (100% by mass) of the ink, and is preferably 0.25 to 0.75. A range of mass% is more preferred.

(3. Polyolefin wax)
When the ink in the present embodiment contains a polyolefin wax, it is possible to further improve the abrasion resistance of the recorded matter. Examples of the polyolefin wax include, but are not limited to, polyethylene wax and polypropylene wax. Among these, polyethylene wax is preferable.

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

  A commercially available product may be used as it is as the polyolefin wax. Among these, commercially available products of polyethylene wax are not limited to the following. For example, Nopcoat PEM17 (trade name, manufactured by SANNOPCO LIMITED), Chemipearl W4005 (trade name, manufactured by Mitsui Chemicals, Inc.) ), AQUACER 515, AQUACER 593 (trade name, manufactured by BYK).

  The average particle diameter of the polyolefin wax is preferably in the range of 5 nm to 400 nm, and 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 polyolefin wax content (in terms of solid content) that can be contained in each ink is preferably in the range of 0 to 1.5% by mass, preferably 0.25 to 0.75, relative to the total mass (100% by mass) of the ink. A range of mass% is more preferred.

  Among those described so far, the resin particles are preferably at least one of a polyolefin wax and a paraffin wax in order to further improve the abrasion resistance of the recorded matter.

  Each ink may contain wax other than polyolefin wax and paraffin wax as resin particles. The wax has a function of imparting slip performance to the surface of the formed recorded matter and improving the abrasion resistance. The wax is preferably contained in the ink in an emulsion state. Since the wax in the ink exists in an emulsion state, the viscosity of the ink can be easily adjusted to an appropriate range in the ink jet recording method, and the storage stability and ejection stability of the ink can be further improved. .

  In addition, when the ink set of the present embodiment further includes another ink different from the first ink and the second ink, the other ink may contain the above-described resin particles.

[Aprotic polar solvent]
The first ink and the second ink included in the ink set of the present embodiment contain an aprotic polar solvent. When the first ink and the second ink contain an aprotic polar solvent, the above-described resin particles contained in these inks are dissolved, so that nozzle clogging is effectively prevented during ink jet recording. can do.

  The aprotic polar solvent contained in the first ink and the second ink may be the same component.

The aprotic polar solvent is not limited to the following, but from the group consisting of pyrrolidones, lactones, sulfoxides, imidazolidinones, sulfolanes, urea derivatives, dialkylamides, cyclic ethers, and amide ethers. It is preferable to include one or more selected.
Specific examples of the pyrrolidones include 2-pyrrolidone, N-methyl-2-pyrrolidone, and N-ethyl-2-pyrrolidone. Specific examples of the lactones include γ-butyrolactone, γ-valerolactone, and ε-caprolactone. Specific examples of the sulfoxides include dimethyl sulfoxide and tetramethylene sulfoxide. Specific examples of the imidazolidinones include 1,3-dimethyl-2-imidazolidinone. Specific examples of the sulfolanes include sulfolane and dimethyl sulfolane. Specific examples of the urea derivative include dimethylurea and 1,1,3,3-tetramethylurea. Specific examples of the dialkylamides include dimethylformamide and dimethylacetamide. Specific examples of the cyclic ethers include 1,4-dioxane and tetrahydrofuran.

  Moreover, as said amide ether, the solvent shown by following General formula (1) corresponds.

... (1)
In the above formula (1), R ¹ is preferably an alkyl group having 1 to 4 carbon atoms. The “C1-C4 alkyl group” may be a linear or branched alkyl group, such as a methyl group, an ethyl group, an n-propyl group, an iso-propyl group, an n-butyl group, It may be an iso-butyl group, a sec-butyl group, or a tert-butyl group. The solvent represented by the formula (1) in which R ¹ is an alkyl group having 1 to 4 carbon atoms can impart appropriate pseudoplasticity to the ink composition, thereby ensuring good ejection stability of the ink. Can do. In addition, the solvent represented by the formula (1) in which R ¹ is an alkyl group having 1 to 4 carbon atoms is preferable because the resin dissolving action is particularly strong.

The HLB value of the solvent represented by the above formula (1) is preferably 10.5 or more and 20.0 or less, more preferably 12.0 or more and 18.5 or less. When the HLB value of the solvent represented by the formula (1) is within the above range, it is more preferable from the viewpoint of imparting appropriate pseudoplasticity to the ink and interaction with the resin component.
The HLB value of the solvent represented by the formula (1) is based on the ratio between the nonpolar value (I) and the organic value (O) in the organic conceptual diagram (hereinafter also simply referred to as “I / O value”). It is a value calculated by the following formula.
HLB value = (Nonpolar value (I) / Organic value (O)) × 10
Specifically, the I / O values are as follows: “Systematic Organic Qualitative Analysis Mixture” (Fujita Kei, Kazama Shobo, 1974), “Dyeing Theory Chemistry” (Kuroki Nobuhiko, Tsuji Shoten, 1966), “ It can be calculated based on each document of “Organic Compound Separation Method” (Hiroo Inoue, Soukabo, 1990).

  Among these aprotic polar solvents, one or more selected from the group consisting of pyrrolidones, lactones, sulfoxides, and amide ethers are more preferable because they have excellent fixability to a recording medium.

  The boiling point of the aprotic polar solvent is preferably 200 ° C. or higher and 260 ° C. or lower.

  Specific examples of the aprotic polar solvent are not limited to the following, but 2-pyrrolidinone is preferably used.

  The aprotic polar solvent contained in each of the first ink and the second ink may be used alone or in combination of two or more.

  The content of the aprotic polar solvent contained in each of the first ink and the second ink is preferably in the range of 3 to 30% by mass, and 8 to 20% by mass with respect to the total mass (100% by mass) of the ink. % Range is more preferred.

  In addition, when the ink set of the present embodiment further includes another ink different from the first ink and the second ink, the other ink may contain the aprotic polar solvent described above.

[Surfactant]
Each ink included in the ink set of the present embodiment may contain a surfactant. Examples of other surfactants include, but are not limited to, nonionic surfactants. The nonionic surfactant has an action of spreading the ink uniformly on the recording medium. Therefore, when ink jet recording is performed using an ink containing a nonionic surfactant, a high-definition image with almost no bleeding can be obtained. Examples of such nonionic surfactants include, but are not limited to, acetylene glycol surfactants, silicon surfactants, polyoxyethylene alkyl ethers, polyoxypropylene alkyl ethers, and polycyclic phenyl ethers. System, sorbitan derivatives, and fluorosurfactants.

  Surfactant may be used individually by 1 type and may use 2 or more types together.

  The content of the surfactant that can be contained in each ink may be in the range of 1.5% by mass or less with respect to the total mass (100% by mass) of the ink.

〔water〕
Each ink included in the ink set 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.

[Other ingredients]
Each ink included in the ink set of the present embodiment further contains, in addition to the above components, an organic solvent other than the above, a pH adjuster, an antiseptic / antifungal agent, a rust inhibitor, a chelating agent, and the like. May be.

[Ink production method]
Each ink included in the ink set of the present embodiment can be obtained by mixing the above-described components (materials) in an arbitrary order, performing filtration or the like as necessary, and removing impurities. Here, when the ink contains a pigment, it is preferable to prepare the pigment in a state of being uniformly dispersed in a solvent before mixing, because the handling becomes simple.

  As a method for mixing each material, a method in which 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, for example, centrifugal filtration or filter filtration can be performed as necessary.

[Recording medium]
The ink set of this embodiment is suitable not only for ink-absorbing recording media but also for ink jet recording using non-ink-absorbing and low-absorbing recording media.

  Examples of the ink-absorbing recording medium include, but are not limited to, dedicated inkjet recording paper such as plain paper, high-quality paper, and glossy paper. Examples of the recording medium with low ink absorption include printing paper such as art paper, coated paper, and matte paper. Examples of non-ink-absorbing recording media include, but are not limited to, plastic films that have not been surface-treated for inkjet printing (that is, that have no ink-absorbing layer formed), and substrates such as paper And those coated with plastic and those with a plastic film adhered thereto. The plastic is not particularly limited, and examples thereof include polyvinyl chloride, polyethylene terephthalate, polycarbonate, polystyrene, polyurethane, polyethylene, and polypropylene.

In this specification, “a non-ink-absorbing and low-absorbing recording medium” means “a water absorption amount of 10 mL / m ² or less from the start of contact to 30 msec ^1/2 in the Bristow method”. Recording 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 described above, according to the present embodiment, an ink set having excellent rub resistance (particularly, rub resistance at the time of color mixing) and intermittent printing characteristics of a recorded matter, an ink jet recording apparatus using the ink set, and the ink set. The recorded matter recorded using can be provided. More specifically, when an ink set composed of a plurality of types of water-based inks is recorded on a non-ink-absorbing and low-absorbing recording medium, even if drying is performed after recording for the purpose of moisture drying, Since the ink in the vicinity of the nozzles can be effectively prevented from drying and solidifying, the intermittent printing characteristics are excellent. In addition, in the above case, the drying efficiency of the recorded matter is increased due to the predetermined relationship between the humectants contained in the first ink and the second ink constituting the ink set, and the recorded matter (image). The rub resistance is excellent.

[Inkjet recording apparatus]
An ink jet recording apparatus according to an embodiment of the present invention performs recording on the above-described recording medium using the ink set of the above embodiment. The ink jet recording apparatus includes an ejection unit and a drying unit.

〔Constitution〕
The discharge means is an ink jet recording method, and forms an image by discharging droplets of each ink constituting an ink set on a recording medium.

  The drying means heats the recording medium on which an image has been formed by ink ejection and landing, and dries the image.

[Operation]
By using the ink set of the above-described embodiment, the ejection unit has excellent intermittent printing characteristics. As the ejection means, a conventionally known method can be used, and in particular, an operation of ejecting droplets using the vibration of a piezoelectric element, that is, a recording operation using a head that forms ink droplets by mechanical deformation of an electrostrictive element. Can be mentioned. By the recording operation, excellent recording can be performed.

  In the above drying means, by heating the recording medium on which the image is formed, moisture contained in the ink ejected on the recording medium is quickly evaporated and scattered, and the resin particles contained in the ink As a result, a film is formed. In this manner, the dried ink is firmly fixed (adhered) on the recording medium, and a high-quality image excellent in abrasion resistance can be obtained in a short time.

  The above-mentioned “heating the recording medium” means raising the recording medium to a desired temperature, and is not limited to directly heating the recording medium.

  Further, the drying means may be executed in parallel with the discharge means or after the discharge means is executed. In other words, the recording medium may be heated before recording, during recording, and after recording. Among them, it is preferable that the recording medium is heated before recording because a high-quality image with little bleeding can be formed on the recording medium, particularly an ink non-absorbing and low-absorbing recording medium. .

  The drying means is not limited to the following, but includes, for example, a platen heater provided in the ink jet recording apparatus, a warm air mechanism provided in the ink jet recording apparatus, and a drying mechanism such as a constant temperature bath connected to the ink jet recording apparatus. And can be executed.

  The temperature of the surface of the recording medium in contact with the ink in the drying means is not particularly limited because it depends on the material of the recording medium.

[Recordings]
The recorded matter according to one embodiment of the present invention is obtained by recording using the ink set of the above embodiment. The recorded matter is excellent in image abrasion resistance.

  EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited to these.

[Raw materials (components)]
The raw materials (components) used in the following examples and comparative examples are as follows.
[Color material]
・ Chromofine blue C.I. I. PB15: 3 (trade name, manufactured by Dainichi Seika Co., Ltd.)
[Resin emulsion]
・ Movinyl 7470 (Nippon Synthetic Chemicals product name)
In Table 1 and Table 2 below, the content of the resin emulsion is shown in terms of solid content.
[Aprotic polar solvent]
・ 2-Pyrrolidinone (boiling point 245 ° C)
[Humectant]
1,2-hexanediol (boiling point: 223 ° C., described as “1,2-HD” in the table below)
Dipropylene glycol (boiling point 229 ° C., described as “DPG” in the table below)
Diethylene glycol (boiling point 244 ° C., described as “DEG” in the table below)
Dibutylene glycol (boiling point 202 ° C., described as “DBG” in the table below)
1,5-pentanediol (boiling point 242 ° C., described as “1,5-PD” in the table below)
Propylene glycol (boiling point 187 ° C., described as “PG” in the table below)
Ethylene glycol (boiling point 196 ° C., described as “EG” in the table below)
1,3-butylene glycol (boiling point: 207 ° C., described as “BG” in the table below)
[Surfactant]
・ BYK-348 (BIC Chemie product name)
〔water〕
·Pure water

[Preparation of pigment dispersion]
Water-soluble resin (methacrylic acid / butyl acrylate / styrene / hydroxyethyl acrylate copolymerized at a mass ratio of 25/50/15/10, weight average molecular weight 12,000) 40 parts by mass, potassium hydroxide 7 parts by mass , 23 parts by mass of water and 30 parts by mass of triethylene glycol mono-n-butyl ether were added and heated at 80 ° C. with stirring to prepare an aqueous resin solution.

  The above-mentioned aqueous resin solution (solid content: 43%) was mixed with 1.75 kg of each of the above pigments and 10.25 kg of water, stirred with a mixing stirrer and premixed to obtain a mixed solution. The above mixed solution was dispersed by a multi-pass method using a horizontal type bead mill equipped with a multi-disc type impeller having an effective volume of 1.5 liters filled with 85% of 0.5 mm zirconia beads. Specifically, two passes were performed at a bead peripheral speed of 8 m / sec and a discharge amount of 30 liters per hour to obtain a pigment dispersion mixed liquid having an average particle diameter of 325 nm. Next, the pigment dispersion mixture was circulated and dispersed using a horizontal annular bead mill having an effective volume of 1.5 liters filled with 95% of 0.05 mm zirconia beads. A screen of 0.015 mm is used, a dispersion of 10 kg of pigment dispersion is performed for 4 hours at a circulation rate of 300 liters / hour at a bead peripheral speed of 10 m / second, a pigment solid content of 20%, a water-soluble resin 5 % Aqueous pigment dispersion was obtained.

[Preparation of ink and ink set]
The first ink and the second ink were respectively prepared with the compositions shown in Table 1 and Table 2 below (however, the pigment dispersion prepared above was used as the colorant in the table) (in the table, color The material is represented by the solid content concentration of the coloring material in the pigment dispersion.) Each ink was prepared by mixing in a container and stirring and mixing with a magnetic stirrer for 2 hours, and then filtering through a membrane filter having a pore size of 5 μm to remove impurities such as dust and coarse particles.
Each ink set was obtained by combining the first ink and the second ink as shown in Table 1 and Table 2 below. In addition, the numerical value of the compounding quantity in Table 1 and Table 2 shows the mass% altogether.

[Evaluation method]
[Abrasion resistance]
A part of the printer PX-G930 (trade name, manufactured by Seiko Epson Corporation) was remodeled so that the recording medium can be heated and adjusted during ink jet recording. The ink cartridge of this printer was filled with ink of each color constituting the ink set of each example and each comparative example, that is, the first ink and the second ink. The inks of the respective colors are ejected onto a recording medium (IJ180 manufactured by 3M) at a resolution of 720 dpi × 720 dpi in width and dried to perform inkjet recording, and a recorded matter composed of a plurality of colors (mixed colors). Got. The recording medium was heated at 45 ° C. during ink jet recording.
After inkjet recording, the obtained recorded matter was dried at 60 ° C. for 1 minute. Thereafter, the recorded matter was allowed to stand at room temperature for 16 hours.
Using a Gakushin type friction fastness tester (AB-01 RUBING TESTER manufactured by TESTER SANGYO CO. LTD, load 500 g), the recorded material was rubbed 50 times with a gold width No. 3, and scratches or peeling occurred on the recording surface. It was visually observed whether or not.

As described above, “rubbing resistance” in this specification refers to a property that an image is not easily peeled off from a recording medium when a frictional force is applied to the image formed on the recording medium. The evaluation criteria are as follows. The evaluation results are shown in Tables 3 and 4.
○: Neither scratch nor peeling was observed.
Δ: One or more scratches were observed, but no peeling was observed.
X: One or more scratches and peelings were observed.

[Intermittent printing characteristics]
Inkjet recording was carried out in the same manner as in the above-described rubbing resistance evaluation, except that each color ink, that is, the first ink and the second ink was discharged after being allowed to stand at an environmental temperature of 50 ° C. for 60 minutes. This evaluation was performed from the viewpoint of how much the landing position of the second shot was shifted. The discharge weight per shot was 7 ng.

Thus, “intermittent printing characteristics” in this specification refers to the property that ink ejected from the printer head does not (almost) deviate from the intended landing position. The evaluation criteria are as follows. The evaluation results are shown in Tables 3 and 4.
A: The deviation width of the landing position was less than 50 μm.
(Triangle | delta): The deviation width | variety of a landing position was 50 micrometers or more.
X: Not discharged.

From the above evaluation results, the first moisturizing agent and the second moisturizing agent that contain the first ink and the second ink having a predetermined composition and are included in the first ink and the second ink, respectively, have a predetermined condition ( It was found that the ink set (each example) that satisfies (A) or (B)) is superior in both intermittent printing characteristics and the rub resistance of the recorded material as compared with the ink set (each comparative example) that is not.
In addition, the evaluation of the first ink is good but the evaluation of the second ink is bad, or the evaluation of the second ink is good but the evaluation of the first ink is bad. It turned out to be different.

Claims (7)

A first ink containing water, a pigment , resin particles, a first humectant, and an aprotic polar solvent, and containing no alkyl polyol having a boiling point of 280 ° C. or higher with respect to the total mass of the ink of 1.0% by mass or more ,
Water, wherein the amount of the pigment exceeds the amount of the pigment first contained in the ink, wherein the resin particles in an amount less than the content of the resin particles contained in the first ink, the second humectant, and the non A second ink that contains a protic polar solvent and does not contain 1.0 mass% or more of an alkyl polyol having a boiling point of 280 ° C. or higher with respect to the total mass of the ink;
Including, and
It meets the following conditions (A) or (B),
The aprotic polar solvent is at least one selected from the group consisting of pyrrolidones, lactones, sulfoxides, imidazolidinones, sulfolanes, urea derivatives, dialkylamides, cyclic ethers, and amide ethers. Including ink set.
(A) the first humectant, (a1) 1,2-hexanediol and solvent der other than the 1,2-hexanediol is, the boiling point of the solvent other than the 1,2-hexanediol is 200 ° C. or higher and at 260 ° C. or less, and a boiling point of the first humectant all SANYO above the boiling point of the second humectant,
The second humectant is (a3) 1,2-hexanediol and a solvent other than the 1,2-hexanediol, and the boiling point of the solvent other than the 1,2-hexanediol is 160 ° C. or higher and 240 ° C. And
Of the first humectant, the solvent other than the 1,2-hexanediol and the second humectant other than the 1,2-hexanediol are glycol ether, polyalkylene glycol, and 1, α-alkane, respectively. One or more selected from diols (except α = 2), ethylene glycol and propylene glycol.
(B) The first moisturizing agent and the second moisturizing agent are 1,2-hexanediol and dipropylene glycol, and the content of dipropylene glycol contained in the first ink is the dihydric acid contained in the second ink. It exceeds the content of propylene glycol. The ink set according to claim 1 , wherein the second humectant is at least one selected from 1,2-hexanediol, glycol ether, and polyalkylene glycol . The ink set according to claim 1 or 2 , wherein the boiling point of the aprotic polar solvent is 200 ° C or higher and 260 ° C or lower. Prior Symbol first ink, and the total content of the solvent other than the 1,2-hexanediol and the 1,2-hexanediol, and the content of the aprotic polar solvent, the mass ratio of 0. The ink set according to any one of claims 1 to 3 , which is 6 to 2.6. The resin particles is at least one of polyolefin wax and paraffin wax, ink set according to any one of claims 1-4. It is recorded using the ink set according to any one of claims 1 to 5 the ink jet recording apparatus. It was recorded using the ink set according to any one of claims 1 to 5 recorded matter.