JP5811344B2 - Non-aqueous ink composition for inkjet recording and inkjet recording method - Google Patents

Description

  The present invention relates to a non-aqueous ink composition for ink jet recording and an ink jet recording method using the same.

  2. Description of the Related Art Conventionally, there is known an ink jet recording method for recording an image or a character on a water-absorbing recording medium such as paper with fine ink droplets ejected from a nozzle of an ink jet recording head. As an ink used for such an ink jet recording method, a water-based ink containing water as a main solvent is widely used. However, ink jet recording methods have recently been used for recording on various recording media in various fields. In particular, a non-aqueous ink that does not substantially contain water as a solvent has been developed in place of the conventional aqueous ink from the viewpoint of corresponding to a printing method for a low-absorbency recording medium.

  As printing methods for low-absorbency recording media, gravure printing for soft packaging materials, flexographic printing for sanitary, silk screen printing for metal plates, inkjet printing for indoor and outdoor advertising, etc. are generally known. However, non-aqueous inks used in these printing methods generally use solvents such as toluene, ethyl acetate, methyl ethyl ketone, methyl isobutyl ketone, cyclohexane, etc., which are the second type organic solvents. Non-water-based inks that are difficult to handle and have higher safety and hygiene have been demanded, such as the installation of local exhaust equipment or the occurrence of regular health checkups.

  From such a viewpoint, non-aqueous inks containing solvents such as glycol ether acetates such as ethylene glycol monobutyl ether acetate and cyclic esters such as γ-butyrolactone, which are not applicable to the second type organic solvent, have been proposed. (For example, refer to Patent Document 1).

JP 2005-200469 A

  However, since the solvent contained in the non-aqueous ink as described above has a poor ability to dissolve the surface of the low-absorbency recording medium, the fixability of an image recorded on the low-absorbency recording medium may be inferior. Further, since the low-absorbency recording medium has a poor ability to absorb the solvent, when the image is recorded on the low-absorbency recording medium using the non-aqueous ink as described above, the surface drying property may be remarkably lowered. . In addition, the non-aqueous ink as described above may have noticeable blurring of the recorded image depending on the type of the low-absorbency recording medium used.

  Some embodiments according to the present invention solve at least a part of the above-described problems, thereby reducing bleeding of an image recorded on a low-absorbency recording medium, and being excellent in image fixability and surface drying. Another object of the present invention is to provide a non-aqueous ink composition for ink jet recording excellent in safety and hygiene, and an ink jet recording method using the same.

  The present invention can be realized as the following aspects or application examples.

[Application Example 1]
One aspect of the non-aqueous ink composition for inkjet recording according to the present invention is:
A compound represented by the following general formula (1):
Lactones,
Containing.

(In Formula (1), R ¹ represents an alkyl group having 1 to 4 carbon atoms, and R ² and R ³ represent a methyl group or an ethyl group.)
According to the non-aqueous ink composition for ink-jet recording of Application Example 1, the fixability and surface drying property of an image recorded on a low-absorbency recording medium (particularly, a recording medium containing a vinyl chloride resin on the recording surface). And the occurrence of bleeding can be suppressed. Moreover, since it is possible to reduce or not contain the second type organic solvent used in the conventional non-aqueous ink composition, it is excellent in terms of safety and hygiene.

[Application Example 2]
In application example 1,
In the general formula (1), R ¹ may be a methyl group.

[Application Example 3]
In application example 1 or application example 2,
The content ratio (MA / MB) of the content [MA (% by mass)] of the compound represented by the general formula (1) and the content [MB (% by mass)] of the lactone is 0. It can be 1 or more and 9 or less.

[Application Example 4]
In any one of Application Examples 1 to 3,
The sum (MA + MB) of the content [MA (mass%)] of the compound represented by the general formula (1) and the content [MB (mass%)] of the lactone is 6 mass% or more and 40 It can be up to mass%.

[Application Example 5]
In any one of Application Examples 1 to 4,
The lactone may be a lactone having 6 or less carbon atoms.

[Application Example 6]
In any one of Application Examples 1 to 5,
Furthermore, an alkylene glycol compound can be contained.

[Application Example 7]
One aspect of the inkjet recording method according to the present invention is:
The droplets of the non-aqueous ink composition for ink jet recording described in any one of the application examples 1 to 6 are ejected, and the droplets are attached to the recording surface containing the vinyl chloride resin to form an image. Record.

[Application Example 8]
In Application Example 7,
The recording surface has an uneven shape,
The height difference of the unevenness may be 0.01 mm or more and 1 mm or less.

  Hereinafter, preferred embodiments of the present invention will be described. 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. Non-aqueous ink composition for ink-jet recording The non-aqueous ink composition for ink-jet recording according to one embodiment of the present invention (hereinafter also simply referred to as “non-aqueous ink composition”) is represented by the general formula (1) described below. And lactones. The compound and lactone represented by the general formula (1) are organic solvents that function as a solvent for non-aqueous inks.

  In the present invention, the term “non-aqueous ink composition” means that water is not intentionally added when the ink composition is produced, and a trace amount that inevitably mixes the ink composition during production or storage. It may also contain water.

  Hereinafter, components contained in the non-aqueous ink composition according to this embodiment will be described in detail.

1.1. Organic Solvent 1.1.1 Compound Represented by General Formula (1) The non-aqueous ink composition according to this embodiment contains a compound represented by the following general formula (1).

In the above formula (1), R ¹ represents an alkyl group having 1 to 4 carbon atoms, and R ² and R ³ represent a methyl group or an ethyl group. The “alkyl group having 1 to 4 carbon atoms” may be a linear or branched alkyl group such as a methyl group, an ethyl group, an n-propyl group, an iso-propyl group, or an n-butyl group. , Sec-butyl group, iso-butyl group, and tert-butyl group. The compounds represented by the above formula (1) may be used singly or in combination of two or more.

  Examples of the function of the compound represented by the formula (1) include improving the surface drying property and the fixing property of the ink deposited on the low-absorbency recording medium. In particular, the compound represented by the above formula (1) is excellent in the action of dissolving the vinyl chloride resin. Therefore, the compound represented by the above formula (1) can dissolve the recording surface containing the vinyl chloride resin and allow the ink to penetrate into the low-absorbency recording medium. As the ink penetrates into the low-absorbency recording medium in this way, the ink is firmly fixed and the surface of the ink is easily dried. Therefore, the obtained image is excellent in abrasion resistance and surface dryness.

In the above formula (1), R ¹ is preferably a methyl group having 1 carbon atom. In the above formula (1), the standard boiling point of the compound in which R ¹ is a methyl group is lower than the standard boiling point of the compound in which R ¹ is an alkyl group having 2 to 4 carbon atoms. Therefore, in the above formula (1), when a compound in which R ¹ is a methyl group is used, the surface drying property of the recorded image may be further improved.

  The HLB value of the compound represented by the formula (1) is preferably 8.0 or more and 20.0 or less, more preferably 8.5 or more and 18.5 or less, and more preferably 12.0 or more and 18. Particularly preferred is 5 or less. When the HLB value of the compound represented by the formula (1) is within the above range, it is more preferable in terms of interaction with the vinyl chloride resin. In addition, the HLB value in this specification is the following formula (2) from the ratio of the nonpolar value (I) and the organic value (O) in the organic conceptual diagram (hereinafter also simply referred to as “I / O value”). Is a value calculated by

HLB value = (Nonpolar value (I) / Organic value (O)) × 10 (2)
Specifically, I / O values are written by Atsushi Fujita, “Systematic Organic Qualitative Analysis Mixture”, Kazama Shobo, 1974; Norihiko Kuroki, “Dyeing Theoretical Chemistry”, Sakai Shoten, 1966; Hiroo Inoue , “Organic Compound Separation Method”, Suikabo, 1990.

  The content of the compound represented by the above formula (1) is preferably 1% by mass or more and 30% by mass or less, and preferably 3% by mass or more and 20% by mass or less with respect to the total mass of the non-aqueous ink composition. More preferably, it is more preferably 10% by mass or more and 20% by mass or less. When the content of the compound represented by the above formula (1) is in the above range, the abrasion resistance and surface drying property of the image may be further improved.

1.1.2. Lactones The non-aqueous ink composition according to this embodiment contains lactones. Examples of the function of lactones include improving the fixability of ink deposited on a low-absorbency recording medium. In particular, lactones are not as good as the compounds represented by the above formula (1), but have a good effect of dissolving vinyl chloride resins, so that the ink of a low-absorbency recording medium containing vinyl chloride resins can be used. Fixability can be improved.

  The lactone is preferably a lactone having 6 or less carbon atoms, and is preferably β-propiolactone, β-butyrolactone, γ-butyrolactone, γ-valerolactone, γ-caprolactone, σ-valerolactone, or ε-caprolactone. More preferred. Lactones may be used alone or in combination of two or more.

  The content of the lactone is preferably 1% by mass or more and 30% by mass or less, more preferably 3% by mass or more and 20% by mass or less, more preferably 10% by mass with respect to the total mass of the non-aqueous ink composition. % To 20% by mass is particularly preferable. When the content of the lactone is in the above range, the abrasion resistance of the image may be improved.

  When a lactone and a compound represented by the above formula (1) are used in combination, the occurrence of blurring of an image on various types of low-absorbency recording media can be suppressed by the synergistic action of these compounds. For example, even if the materials constituting the low-absorbency recording medium are the same, depending on the surface state, bleeding may easily occur in the recorded image. In such a case, by using both compounds (the lactones and the compound represented by the above formula (1)) in combination, a good image with little bleeding can be recorded regardless of the surface state of the low-absorbency recording medium. .

  The content ratio (MA / MB) of the content [MA (mass%)] of the compound represented by the general formula (1) and the content of lactones [MB (mass%)] is 0.1. It is preferably 9 or less and more preferably 0.5 or more and 2 or less. When the content ratio of both compounds is within the above range, an image having less bleeding and excellent surface drying and abrasion resistance can be obtained.

  The total (MA + MB) of the content [MA (mass%)] of the compound represented by the general formula (1) and the content [MB (mass%)] of the lactone is 6 mass% or more. It is preferably 40% by mass or less, more preferably 10% by mass or more and 40% by mass or less, and particularly preferably 20% by mass or more and 30% by mass or less. When the total content of both compounds is within the above range, an image with less bleeding and excellent surface dryness and abrasion resistance can be obtained. In particular, since the total of both compounds does not exceed 30% by mass, the ink droplets adhering to the low-absorbency recording medium can be maintained in an appropriate size, so that the ink filling is good and the stripes are uneven. In some cases, fewer images may be obtained. Moreover, when both compounds are contained in an amount of 10% by mass or more, bleeding of an image may be more difficult to occur.

1.2. Other Components The non-aqueous ink composition according to the present embodiment may contain an organic solvent other than the organic solvent described above, a surfactant, a pigment, a dispersant, and the like as necessary.

1.2.1. Other Organic Solvent The non-aqueous ink composition according to this embodiment preferably contains an alkylene glycol compound that is liquid at normal temperature and pressure from the viewpoint of firmly fixing the ink to the vinyl chloride resin.

  The alkylene glycol compound is preferably an ethylene glycol compound or a propylene glycol compound as described in International Publication No. 2002/055619 pamphlet.

  In the case where the non-aqueous ink composition according to this embodiment contains an alkylene glycol compound, it can be appropriately selected depending on the printing characteristics, but the content thereof is 20 mass relative to the total mass of the non-aqueous ink composition. % Or more and 85% by mass or less is preferable.

  Preferred ethylene glycol compounds include ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, or polyethylene glycol monoethers or diethers, with diethylene glycol compounds being preferred. Preferred propylene glycol compounds include propylene glycol, dipropylene glycol, tripropylene glycol, or polypropylene glycol monoether or diether, preferably dipropylene glycol. Among the ethylene glycol compounds, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monoethyl ether acetate and ethylene glycol monobutyl ether are classified as the second type organic solvent, so that the handling difficulty, environment, etc. From the viewpoint of reducing the load on the battery, it is preferable not to use it.

  As the diethylene glycol compound, for example, a diethylene glycol compound represented by the following general formula (3) can be used.

In formula (3), R ⁴ and R ⁵ are each independently a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or an R ⁶ CO group. R ⁶ is 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 can be a sec-butyl group or a tert-butyl group. Specific examples of the diethylene glycol compound represented by the formula (3) include diethylene glycol, diethylene glycol monomethyl ether, diethylene glycol dimethyl ether, diethylene glycol methyl ethyl ether, diethylene glycol monoethyl ether, diethylene glycol diethyl ether, diethylene glycol mono n-butyl ether, diethylene glycol di n-butyl ether, Examples include diethylene glycol butyl methyl ether, diethylene glycol monoethyl ether acetate, and diethylene glycol mono n-butyl ether acetate.

  As the dipropylene glycol compound, for example, a dipropylene glycol compound represented by the following general formula (4) can be used.

In formula (4), R ⁷ and R ⁸ are each independently a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or an R ⁹ CO group. R ⁹ is 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 can be a sec-butyl group or a tert-butyl group. Examples of the dipropylene glycol compound represented by the formula (4) include dipropylene glycol, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, and the like.

  The diethylene glycol compound and dipropylene glycol compound that can be used in the non-aqueous ink composition according to this embodiment preferably have a boiling point of 150 ° C. or higher, more preferably 180 ° C. or higher, respectively, under normal pressure.

  Further, the diethylene glycol compound and the dipropylene glycol compound that can be used in the non-aqueous ink composition according to the present embodiment have a vapor pressure at 20 ° C. of preferably 1 hPa or less, more preferably 0.7 hPa or less. is there.

  By using a diethylene glycol compound and a dipropylene glycol compound that satisfy the high boiling point and low vapor pressure conditions as described above, the burden of installing a local exhaust facility or exhaust gas treatment facility is reduced, and the work environment can be improved. It is also possible to reduce the environmental load on the surrounding environment.

  In addition to the diethylene glycol compound, dipropylene glycol compound, or mixture thereof described above, the non-aqueous ink composition according to the present embodiment is a liquid at normal temperature and pressure, and is represented by the following general formula (5). An alkylene glycol compound may be contained.

In Formula (5), R ¹⁰ is an alkylene group having 2 to 3 carbon atoms. R ¹¹ and R ¹² are each independently a hydrogen atom or an alkyl group having 1 to 6 carbon atoms (preferably an alkyl group having 1 to 4 carbon atoms). n is an integer of 3-6. Examples of the alkylene group having 2 to 3 carbon atoms include an ethylene group and a propylene group. The “C 1-6 alkyl group” may be a linear or branched alkyl group. For example, in addition to the “C 1-4 alkyl group”, a linear or branched alkyl group may be used. It can be a pentyl group or a hexyl group.

  The polyalkylene glycol compound that can be used in the non-aqueous ink composition according to this embodiment has a boiling point of 200 ° C. or higher, more preferably 250 ° C. or higher, under normal pressure. The flash point is preferably 100 ° C. or higher, more preferably 130 ° C. or higher. By using such a polyalkylene glycol compound, volatilization suppression can be imparted to the non-aqueous ink composition. For example, by suppressing the volatilization of the non-aqueous ink composition in the tube that transports the non-aqueous ink composition from the ink cartridge to the inkjet recording head, it is possible to prevent or reduce the accumulation of solids in the tube. it can.

  Preferred polyalkylene glycol compounds include, for example, polyalkylene glycol monoalkyl ether, polyalkylene glycol dialkyl ether and the like. These compounds may be used individually by 1 type, and may be used in mixture of 2 or more types.

  Examples of the polyalkylene glycol monoalkyl ether include triethylene glycol monomethyl ether, triethylene glycol monobutyl ether, tripropylene glycol monobutyl ether, polyethylene glycol monobutyl ether in which n is 4 or more and 6 or less in the general formula (5), tetra Examples include ethylene glycol monomethyl ether, pentaethylene glycol monomethyl ether, and hexaethylene glycol monomethyl ether.

  Examples of the polyalkylene glycol dialkyl ether include tetraethylene glycol dimethyl ether.

  Further, the non-aqueous ink composition according to this embodiment may further contain an organic solvent exemplified below in addition to the organic solvent exemplified above.

  Other organic solvents are preferably polar organic solvents such as alcohols (eg, ethyl alcohol, 1-propanol, fluorinated alcohol, etc.), ethers (eg, diethyl ether, dipropyl ether, etc.) and the like. .

  In addition, the non-aqueous ink composition according to the present embodiment contains a second type organic solvent (see Attached Table 6-2 of the Industrial Safety and Health Act Enforcement Ordinance) from the viewpoint of ease of handling and reduction of environmental load. Preferably not.

1.2.2. Surfactant In addition to the organic solvent, the non-aqueous ink composition according to the embodiment includes a silicon surfactant, a fluorine-based surfactant, from the viewpoint of reducing surface tension and improving wettability with a recording medium. An agent or a polyoxyethylene derivative that is a nonionic surfactant may be added.

  As the silicon surfactant, it is preferable to use polyester-modified silicon or polyether-modified silicon. Specific examples include BYK-347, 348, BYK-UV3500, 3510, 3530, 3570 (all manufactured by Big Chemie Japan).

  As the fluorine-based surfactant, a fluorine-modified polymer is preferably used, and specific examples thereof include BYK-340 (manufactured by BYK Japan).

  As the polyoxyethylene derivative, it is preferable to use an acetylene glycol surfactant. Specific examples include Surfinol 82, 104, 465, 485, TG (all manufactured by Air Products Japan), Olphine STG, E1010 (all manufactured by Nissin Chemical Co., Ltd.), Nissan Nonion A-10R, A-13R. (All manufactured by NOF Corporation), Floren TG-740W, D-90 (manufactured by Kyoeisha Chemical Co., Ltd.), Neugen CX-100 (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) and the like.

  The content of the surfactant in the non-aqueous ink composition according to this embodiment is preferably 0.05% by mass to 3% by mass, more preferably 0.5% by mass to 2% by mass.

1.2.3. Pigment In the non-aqueous ink composition according to this embodiment, a pigment such as a colored inorganic pigment or a colored organic pigment that is usually used in a conventional non-aqueous ink composition can be used as a color material. These pigments may be used alone or in combination of two or more.

  Examples of the pigment include azo pigments such as azo lakes, insoluble azo pigments, condensed azo pigments and chelate azo pigments; phthalocyanine pigments, perylene and perylene pigments, anthraquinone pigments, quinacridone pigments, dioxazine pigments, thioindigo pigments, isoindolinone pigments, quinophthalone Polycyclic pigments such as pigments; dye lakes such as basic dye type lakes and acid dye type lakes; organic pigments such as nitro pigments, nitroso pigments, aniline black, daylight fluorescent pigments; inorganic pigments such as carbon black It is done. The average primary particle size of the pigment particles is not particularly limited, but is preferably 50 nm or more and 500 nm or less.

  Examples of the pigment when the non-aqueous ink composition according to this embodiment is magenta or red ink include C.I. I. Pigment red 2, C.I. I. Pigment red 3, C.I. I. Pigment red 5, C.I. I. Pigment red 6, C.I. I. Pigment red 7, C.I. I. Pigment red 15, C.I. I. Pigment red 16, C.I. I. Pigment red 48: 1, C.I. I. Pigment red 53: 1, C.I. I. Pigment red 57: 1, C.I. I. Pigment red 122, C.I. I. Pigment red 123, C.I. I. Pigment red 139, C.I. I. Pigment red 144, C.I. I. Pigment red 149, C.I. I. Pigment red 166, C.I. I. Pigment red 170, C.I. I. Pigment red 177, C.I. I. Pigment red 178, C.I. I. Pigment red 194, C.I. I. Pigment red 209, C.I. I. Pigment red 222, C.I. I. And CI Pigment Red 224.

  Examples of the pigment when the non-aqueous ink composition according to this embodiment is an orange or yellow ink include C.I. I. Pigment orange 31, C.I. I. Pigment orange 43, C.I. I. Pigment orange 64, C.I. I. Pigment yellow 12, C.I. I. Pigment yellow 13, C.I. I. Pigment yellow 14, C.I. I. Pigment yellow 15, C.I. I. Pigment yellow 17, C.I. I. Pigment yellow 74, C.I. I. Pigment yellow 93, C.I. I. Pigment yellow 94, C.I. I. Pigment yellow 128, C.I. I. Pigment yellow 138, C.I. I. Pigment yellow 150, C.I. I. And CI Pigment Yellow 180.

  Examples of the pigment when the non-aqueous ink composition according to this embodiment is a green or cyan ink include C.I. I. Pigment blue 15, C.I. I. Pigment blue 15: 2, C.I. I. Pigment blue 15: 3, C.I. I. Pigment blue 16, C.I. I. Pigment blue 60, C.I. I. Pigment green 7, C.I. I. And CI Pigment Green 36.

  Examples of the pigment when the non-aqueous ink composition according to this embodiment is a black ink include carbon black.

  Examples of the pigment when the non-aqueous ink composition according to this embodiment is a white ink include Pigment White 6, 18, 21 and the like.

  The content of the pigment in the non-aqueous ink composition according to this embodiment can be appropriately selected depending on the application and printing characteristics, but is preferably 0.5% by mass or more and 25% by mass or less, more preferably 0.5%. The content is from 1% by mass to 15% by mass, particularly preferably from 1% by mass to 10% by mass.

  In the non-aqueous ink composition according to this embodiment, any dispersant used in a normal non-aqueous ink composition can be used from the viewpoint of improving the dispersion stability of the pigment. As the dispersant, it is preferable to use a dispersant that works effectively when the solubility parameter of the organic solvent is 8 to 11. Specific examples of such a dispersant include polyester polymers such as Hinoact KF1-M, T-6000, T-7000, T-8000, T-8350P, and T-8000E (all manufactured by Takefu Fine Chemical Co., Ltd.). Compound, Solsperse 20000, 24000, 32000, 32500, 33500, 34000, 35200, 37500 (all manufactured by LUBRIZOL), Disperbyk-161, 162, 163, 164, 166, 180, 190, 191, 192 (all are Big Chemie Japan) ), Floren DOPA-17, 22, 33, G-700 (all manufactured by Kyoeisha Chemical Co., Ltd.), Ajisper PB821, PB711 (all manufactured by Ajinomoto Co., Inc.), LP4010, LP4050, LP4055, P LYMER400,401,402,403,450,451,453 (both EFKA Chemicals Co., Ltd.), and the like.

  In the non-aqueous ink composition according to this embodiment, the content of the dispersant can be appropriately selected depending on the pigment to be dispersed, but with respect to 100 parts by mass of the pigment in the non-aqueous ink composition. Preferably, it is 5 to 200 mass parts, More preferably, it is 30 to 120 mass parts.

1.2.4. Other components The non-aqueous ink composition according to the present embodiment may further contain other additives contained in a normal non-aqueous ink composition. Examples of other additives include stabilizers such as antioxidants and ultraviolet absorbers, and binder resins.

  Examples of the antioxidant include BHA (2,3-butyl-4-oxyanisole), BHT (2,6-di-t-butyl-p-cresol) and the like.

  Examples of the ultraviolet absorber include benzophenone compounds and benzotriazole compounds.

  In the non-aqueous ink composition according to this embodiment, a binder resin may be added for the purpose of adjusting the viscosity of the ink. Examples of the binder resin include acrylic resins, styrene acrylic resins, rosin modified resins, phenol resins, terpene resins, polyester resins, polyamide resins, epoxy resins, vinyl chloride vinyl acetate copolymer resins, cellulose acetate butyrate, and the like. Resin, vinyltoluene-α-methylstyrene copolymer resin, and the like. These binder resins may be used alone or in combination of two or more. The binder resin can further improve the fixability of the ink to the vinyl chloride resin depending on the amount of the binder resin added.

1.3. Method for Producing Non-Aqueous Ink Composition The non-aqueous ink composition according to this embodiment can be produced by a known conventional method. In the case of using a pigment as a colorant, first, a pigment, a dispersant, and an organic solvent (partial) are mixed, and then a pigment dispersion is prepared by a ball mill, a bead mill, an ultrasonic wave, a jet mill or the like, Adjust to have ink characteristics. Subsequently, an organic solvent (remaining amount) and other additives (for example, a surfactant and a binder resin) can be added with stirring to obtain a non-aqueous ink composition.

1.4. Physical Properties The non-aqueous ink composition according to this embodiment preferably has a surface tension at 20 ° C. of 20 mN / m or more and 50 mN / m from the viewpoint of the balance between recording quality and reliability as an ink composition for inkjet. 25 mN / m or more and 40 mN / m or less is more preferable. The surface tension is measured by using an automatic surface tension meter CBVP-Z (manufactured by Kyowa Interface Science Co., Ltd.) by confirming the surface tension when the platinum plate is wetted with ink in an environment of 20 ° C. be able to.

  From the same viewpoint, the viscosity at 20 ° C. of the non-aqueous ink composition according to this embodiment is preferably 2 mPa · s to 15 mPa · s, and preferably 2 mPa · s to 10 mPa · s. More preferred. The viscosity is measured by using a viscoelasticity tester MCR-300 (manufactured by Pysica), increasing the Shear Rate to 10 to 1000 in an environment of 20 ° C., and reading the viscosity at Shear Rate 200. Can be measured.

2. Inkjet recording method The inkjet recording method according to this embodiment ejects droplets of the non-aqueous ink composition described above, and attaches the droplets to a low-absorbency recording medium to record an image.

In the present specification, the “low-absorbency recording medium” refers to a recording medium having 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, and at least the recording target The surface only needs to have this property. 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". The low-absorbency recording medium includes a non-absorbent recording medium that does not absorb water at all.

  Specific examples of the low-absorbency recording medium include sheets, films, and textile products containing a low-absorbency material. The low-absorbency recording medium is a layer containing a low-absorbency material (hereinafter referred to as “low-absorbency layer”) on the surface of a substrate (for example, paper, fiber, leather, plastic, glass, ceramics, metal, etc.). May also be provided). Although it does not specifically limit as a low absorptive material, Olefin resin, ester resin, urethane resin, acrylic resin, vinyl chloride resin etc. are mentioned.

  Among these, as the low-absorbency recording medium, one having a recording surface containing a vinyl chloride resin can be preferably used. Specific examples of the vinyl chloride resin include polyvinyl chloride resin, vinyl chloride-ethylene copolymer resin, vinyl chloride-vinyl acetate copolymer resin, vinyl chloride-vinyl ether copolymer resin, vinyl chloride-vinylidene chloride copolymer Polymer resin, vinyl chloride-maleic acid ester copolymer resin, vinyl chloride- (meth) acrylic acid copolymer resin, vinyl chloride- (meth) acrylic acid ester copolymer resin, vinyl chloride-urethane copolymer resin, etc. These may be used alone or in combination of two or more. In the present specification, “(meth) acryl” means at least one of acrylic and methacryl corresponding thereto.

  By the way, although the reason is not clear, if the surface of the low-absorbency recording medium is uneven, ink droplets attached to the recording medium may flow and bleeding may occur in the recorded image. According to the non-aqueous ink according to the present embodiment, the low-absorbency recording medium is not only provided with a smooth recording surface (difference in height of the unevenness of less than 0.01 mm), but also has an uneven shape on the recording surface. What has is also preferably used. The height difference of the unevenness is preferably 0.01 mm or more and 1 mm or less, and is measured using an optical microscope or the like. The concavo-convex shape may be formed by a known processing method such as embossing, or when a recording medium having a low-absorbent layer on the recording surface is used, it is derived from the underlying layer of the low-absorbent layer May be.

  Specifically, the uneven shape formed from the base layer is formed by laminating a low-absorbency layer on the base layer of a fiber base fabric (for example, woven fabric, knitted fabric, non-woven fabric, etc.) It can be formed by placing a low absorption layer. Examples of materials (fibers) used for the fiber base fabric include synthetic fibers such as polyethylene fiber, polypropylene fiber, polyester fiber, nylon fiber, and vinylon fiber, and natural fibers such as cotton, hemp, silk, and wool.

  Various characteristics such as thickness, shape, color, softening temperature, and hardness of the low-absorbency recording medium are not particularly limited.

  The non-aqueous ink composition described above contains the compound represented by the general formula (1) and lactones, and both compounds are excellent in the action of dissolving the vinyl chloride resin and are synergistic. The action is excellent in suppressing the bleeding of the image. Therefore, the ink jet recording method according to the present embodiment has less blur due to adhesion of the droplets of the non-aqueous ink composition described above to the recording surface containing the vinyl chloride resin, and thereby has a fixing property and a surface drying property. A better image can be recorded.

  The ink jet recording apparatus used in the ink jet recording method according to the present embodiment is not particularly limited, but a drop-on-demand ink jet recording apparatus is preferable. The drop-on-demand ink jet recording apparatus employs a piezoelectric element recording method in which recording is performed using a piezoelectric element disposed in a recording head, and heat generated by a heater of a heating resistance element disposed in the recording head. There are methods that employ a thermal jet recording method in which recording is performed using energy, and any recording method can be employed. Further, since the non-aqueous ink composition according to the present embodiment has an advantage that it is inactive with respect to the discharge nozzle surface subjected to the ink repellent treatment, for example, for inkjet recording having the discharge nozzle surface subjected to the ink repellent treatment. It can be advantageously used in an ink jet recording method for discharging from a head.

3. Examples Hereinafter, embodiments of the present invention will be described more specifically with reference to examples and comparative examples. However, the present embodiment is not limited to only these examples.

3.1. Synthesis of organic solvent 3.1.1. Compound represented by the following formula (6) Into a 300 ml separable flask equipped with a stirrer, a thermocouple and a nitrogen gas inlet tube, 19.828 g of N, N-dimethylacrylamide and 6.408 g of methanol were introduced, and nitrogen gas was introduced. While stirring. Next, 0.338 g of sodium t-butoxide was added and reacted at 35 ° C. for 4 hours. After completion of heating, 150 mg of phosphoric acid was added to make the solution uniform, and the mixture was allowed to stand for 3 hours. The solution was filtered to remove precipitates, and unreacted substances were removed with an evaporator. In this way, a compound represented by the following formula (6) (hereinafter also referred to as “organic solvent A”) was obtained.

  In addition, the HLB value calculated by the said Formula (2) from the I / O value in an organic conceptual diagram of the obtained organic solvent A was 18.3.

3.1.2. Compound represented by the following formula (7) Into a 300 ml separable flask equipped with a stirrer, a thermocouple and a nitrogen gas introduction tube, 19.828 g of N, N-dimethylacrylamide and 14.824 g of 1-butanol were added, and nitrogen gas was added. Was stirred while being introduced. Next, 0.338 g of sodium t-butoxide was added and reacted at 35 ° C. for 4 hours. After completion of heating, 150 mg of phosphoric acid was added to make the solution uniform, and the mixture was allowed to stand for 3 hours. The solution was filtered to remove precipitates, and unreacted substances were removed with an evaporator. In this way, a compound represented by the following formula (7) (hereinafter also referred to as “organic solvent B”) was obtained.

  In addition, the HLB value calculated by the said Formula (2) from the I / O value in an organic conceptual diagram of the obtained solvent B was 12.2.

3.2. Preparation of non-aqueous ink composition Into a container, an organic solvent in an amount corresponding to the concentrations shown in Tables 1 and 2 was added for each ink, and mixed and stirred for 30 minutes using a magnetic stirrer to obtain a mixed solvent. .

  Part of the obtained mixed solvent was separated, and Solsperse 37500 (trade name, manufactured by LUBRIZOL) and C.I. I. A predetermined amount of CI Pigment Black 7 (trade name “CARBON BLACK # 970” manufactured by Mitsubishi Chemical Corporation) was added, and the mixture was pulverized using a homogenizer. Then, a pigment dispersion (average particle diameter of pigment: 150 nm) was obtained by performing a dispersion treatment with a bead mill filled with zirconia beads having a diameter of 0.3 mm.

  To the obtained pigment dispersion, the remainder of the organic solvent, BYK-340 (BIC Chemie Japan Co., Ltd., fluorinated surfactant), and Paraloid B60 (Rohm and Haas Co., acrylic resin) are further added. After mixing and stirring for 1 hour, the black ink composition described in Tables 1 and 2 was obtained by filtering using a 5 μm PTFE membrane filter. In addition, the numerical value in a table | surface represents the mass%.

The materials used in the table are as follows.
・ C. I. Pigment Black 7 (Mitsubishi Chemical Corporation, trade name “Carbon Black # 970”, black pigment)
・ Solsperse 37500 (trade name, manufactured by LUBRIZOL, dispersant)
・ Γ-Butyrolactone (manufactured by Kanto Chemical Co., Inc., organic solvent)
・ Γ-valerolactone (organic solvent, manufactured by Kanto Chemical Co., Inc.)
・ Σ-valerolactone (manufactured by Kanto Chemical Co., Inc., organic solvent)
・ Diethylene glycol diethyl ether (Nippon Emulsifier Co., Ltd., organic solvent)
・ Diethylene glycol ethyl methyl ether (trade name “Hisolv EDM”, manufactured by Toho Chemical Co., Ltd., organic solvent)
・ Tetraethylene glycol dimethyl ether (trade name “Hisolv METM”, manufactured by Toho Chemical Industry Co., Ltd., organic solvent)
-BYK-340 (trade name, manufactured by BYK Japan, fluorinated surfactant)

3.3. Evaluation test 3.3.1. Friction fastness test Using a printer “SP-300V” manufactured by J Roland DG, each ink composition obtained in “3.2. Preparation of Non-Aqueous Ink Composition” was treated with a glossy polyvinyl chloride sheet (Roland DG). And “SV-G-1270G”), and printing was performed under the condition of Duty 100%. Then, the sample for evaluation was obtained by making it dry at normal temperature for 1 day.

Next, in accordance with Japanese Industrial Standard “JIS L 0849”, a dry test was performed on an evaluation sample using an I-type testing machine. Thereafter, the OD value of the test cotton fabric was measured with Spectrolino (manufactured by Gretag Macbeth). The evaluation criteria are as follows. An evaluation result is combined with Table 1 and Table 2, and is shown.
6: OD value is less than 0.20 5: OD value is 0.20 or more and less than 0.25 4: OD value is 0.25 or more and less than 0.30 3: OD value is 0.30 or more and less than 0.35 2: OD value is 0.35 or more and less than 0.40 1: OD value is 0.40 or more

3.3.2. Surface dryness test Using a printer “SP-300V” manufactured by J Roland DG, each ink composition obtained in “3.2. Preparation of Non-Water-Based Ink Composition” was used as a glossy polyvinyl chloride sheet (Roland DG). (“SV-G-1270G”) manufactured under the condition of 100% duty, and then dried for 5 minutes. Next, the scratch marks on the glossy surface after the glossy polyvinyl chloride sheet was wound up using a winder were observed. The scratch marks were observed by measuring the surface roughness with a shape measurement laser microscope (manufactured by Keyence Corporation, “VK-8700 Generation II”) to calculate the ratio of the area with the scratch marks. The evaluation criteria are as follows. An evaluation result is combined with Table 1 and Table 2, and is shown.
6: Scratch area is 0%
5: Scratch area is more than 0% and less than 10% 4: Scratch area is 10% or more and less than 20% 3: Scratch area is 20% or more and less than 30% 2: Scratch area is 30% or more and less than 40% 1: Scratch area is 40% or more

3.3.3. Bleeding test Using a printer “SP-300V” manufactured by J Roland DG, each ink composition obtained in “3.2. Preparation of non-aqueous ink composition” was used as a PVC banner sheet (3J, IJ8451, On a recording surface with a low-absorbency recording medium) and a glossy polyvinyl chloride sheet ("SV-G-1270G", low-absorption recording medium with a smooth recording surface) manufactured by Roland DG. The alphabets A to Z (uppercase and lowercase) were printed at a font size of 20 points under the condition of 100% duty, and then dried for 60 minutes. Thereafter, bleeding was observed with the naked eye.

  In addition, the surface of the PVC banner sheet before printing was observed with a shape measurement laser microscope (manufactured by Keyence Corporation, “VK-8700 Generation II”), and the surface unevenness shape was randomly selected at 10 points. And when the height difference of the unevenness was measured, the arithmetic average of 10 points was 0.26 mm (minimum value 0.12 mm, maximum value 0.37 mm).

The evaluation criteria are as follows. An evaluation result is combined with Table 1 and Table 2, and is shown.
3: No bleeding is observed 2: All characters can be easily distinguished, and almost no bleeding is observed 1: All characters can be barely distinguished, but bleeding is clearly recognized

3.3.4. Dot size determination test Using a printer “SP-300V” manufactured by J Roland DG, each ink composition obtained in “3.2. Preparation of non-aqueous ink composition” was used as a PVC banner sheet (manufactured by 3M, IJ8451) was printed on the condition that the dots did not overlap each other. Specifically, a 3 cm square was printed under a duty of 30%, and then dried for 60 minutes. Then, the dot size was observed using the optical microscope, and the diameter was classified every 10 μm. An evaluation result is combined with Table 1 and Table 2, and is shown. If the dot size is 80 μm or less, an image having a resolution of 300 dpi or more can be printed.

3.3.5. Evaluation Results According to Examples 1 to 9, it was shown that the use of the compound represented by the above formula (1) and the lactone in combination with an organic solvent is excellent in surface drying property and abrasion resistance. In addition, it was shown that an excellent image with less blurring can be obtained on low-absorbency recording media having different surface states due to the synergistic effect of these organic solvents.

  According to Comparative Examples 1 to 3, an excellent image could not be obtained because the compound represented by the above formula (1) and lactones were not used in combination. In particular, under the condition where dots overlap each other, blurring of an image occurred on a low-absorbency recording medium having an uneven shape on the recording surface. Moreover, according to the comparative example 3, since the compound represented by the said Formula (1) was not used, friction fastness and surface dryness were also not favorable.

  The present invention is not limited to the embodiments described above, and various modifications are possible. 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)

A compound represented by the following general formula (1):
Lactones,
A non-aqueous ink composition for inkjet recording, comprising:

(In Formula (1), R ¹ represents an alkyl group having 1 to 4 carbon atoms, and R ² and R ³ represent a methyl group or an ethyl group.) In claim 1,
The non-aqueous ink composition for inkjet recording whose R < ¹ > is a methyl group in the said General formula (1). In claim 1 or claim 2,
The content ratio (MA / MB) of the content [MA (% by mass)] of the compound represented by the general formula (1) and the content [MB (% by mass)] of the lactone is 0. A non-aqueous ink composition for inkjet recording, which is 1 or more and 9 or less. In any one of Claims 1 thru | or 3,
The sum (MA + MB) of the content [MA (mass%)] of the compound represented by the general formula (1) and the content [MB (mass%)] of the lactone is 6 mass% or more and 40 A non-aqueous ink composition for ink-jet recording, having a mass% or less. In any one of Claims 1 thru | or 4,
A non-aqueous ink composition for ink jet recording, wherein the lactone is a lactone having 6 or less carbon atoms. In any one of Claims 1 thru | or 5,
Furthermore, the non-aqueous ink composition for inkjet recording containing an alkylene glycol compound.   A droplet of the non-aqueous ink composition for ink jet recording according to any one of claims 1 to 6 is ejected, and the droplet is attached to a recording surface containing a vinyl chloride resin to form an image. An ink jet recording method for recording. In claim 7,
The recording surface has an uneven shape,
The ink jet recording method, wherein the unevenness of the unevenness is 0.01 mm or more and 1 mm or less.