JP2016160369A - Non-aqueous ink composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a non-aqueous ink composition that can record an image good in glossiness, uneven aggregation and rubbing resistance and is excellent in long-term storage stability.SOLUTION: The non-aqueous ink composition contains carbon black as a pigment, a lactone-based solvent, a glycol ether-based solvent having an HLB value of 8 or more, and as a pigment dispersant, a pigment derivative into which a polar group having no amine structure is introduced.SELECTED DRAWING: None

Description

  The present invention relates to a non-aqueous ink composition.

  2. Related Art Inkjet recording apparatuses that record images and characters by ejecting minute droplets of an ink composition from nozzle holes of a recording head and attaching them to a recording medium are known. As an ink composition used for such recording, a water-based ink composition in which a pigment, a pigment dispersant, a resin, or the like is dispersed or dissolved in water is known. Furthermore, development of non-aqueous ink compositions in which pigments, pigment dispersants, resins and the like are dispersed or dissolved in organic solvents without containing water has also been carried out.

  Among the inks described above, the non-aqueous ink composition has good wet-spreadability and fixability of the ink with respect to a recording medium having a recording surface of plastic (for example, vinyl chloride, polyester, polypropylene, polyethylene, etc.). Widely used for recording media having a plastic recording surface. In this non-aqueous ink composition, an organic solvent such as a glycol derivative, a pyrrolidone derivative, or a sulfolane can be used in addition to a five-membered heterocyclic compound having a C═O bond such as a lactone compound, a carbonate compound, or an imidazolidinone compound. Is disclosed (for example, Patent Document 1).

  In addition, a synergist (pigment derivative) as a pigment dispersant or dispersion aid may be added to the non-aqueous ink composition from the viewpoint of improving the dispersibility of the pigment and improving the storage stability of the ink. (For example, refer to Patent Document 2). This synergist is considered to enter between pigment molecules and between the crystal structures of pigments by having a structure similar to pigments. It is presumed that the synergists that have entered between the pigment molecules or between the crystal structures of the pigment have an anti-aggregation structure such as a functional group, thereby preventing the aggregation of pigment molecules and crystals.

JP 2012-107174 A JP 2011-127091 A

  As described above, in the non-aqueous ink composition, a synergist can be used as a pigment dispersant or dispersion aid, and a lactone solvent or glycol ether solvent can be used as a solvent. Of these solvents, lactone solvents have a high ability to dissolve synergists and can improve the abrasion resistance of images on the plastic recording surface. On the other hand, a glycol ether solvent is desirably used as a main solvent because it can improve the glossiness of an image and reduce aggregation unevenness.

  However, since the glycol ether solvent has strong hydrophilicity and high hygroscopicity, the water content in the non-aqueous ink composition may be significantly increased during long-term storage. When the amount of water in the non-aqueous ink composition increases during long-term storage, the dissolved synergist becomes difficult to dissolve, and there is a problem that the storage stability is lowered due to the formation of foreign matter.

  Some aspects of the present invention provide a non-aqueous system capable of recording an image having good gloss, aggregation unevenness, and abrasion resistance, and having excellent long-term storage stability by solving at least a part of the problems described above. It is to provide an ink composition.

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

[Application Example 1]
One aspect of the non-aqueous ink composition according to the present invention is:
Carbon black as a pigment,
A lactone solvent,
A glycol ether solvent having an HLB value of 8 or more;
As a pigment dispersant, a pigment derivative introduced with a polar group having no amine structure,
It is characterized by containing.

  According to the non-aqueous ink composition of Application Example 1, the dispersion stability of carbon black can be improved by using a pigment derivative having a polar group having no amine structure as a carbon black dispersant or dispersion aid. It becomes good. Further, by using a combination of the above components, it is possible to record an image excellent in glossiness, uneven aggregation, and abrasion resistance. Among the above components, the glycol ether solvent has a particularly high hygroscopic property, so that the water content in the non-aqueous ink composition may be significantly increased during long-term storage in a high humidity environment. According to this non-aqueous ink composition, even when the amount of water in the non-aqueous ink composition increases during long-term storage, it is possible to suppress the generation of foreign substances derived from the pigment derivative (synergist).

[Application Example 2]
In the non-aqueous ink composition of Application Example 1,
The pigment derivative may be a phthalocyanine derivative.

[Application Example 3]
In the non-aqueous ink composition of Application Example 1 or Application Example 2,
The content of the pigment derivative may be 0.05% by mass or more and 5% by mass or less with respect to the total mass of the non-aqueous ink composition.

[Application Example 4]
In the non-aqueous ink composition of any one of Application Examples 1 to 3,
The lactone solvent may have 2 to 9 carbon atoms.

[Application Example 5]
In the non-aqueous ink composition of any one of Application Examples 1 to 4,
The content of the lactone solvent may be 5% by mass or more and 50% by mass or less with respect to the total mass of the non-aqueous ink composition.

[Application Example 6]
In the non-aqueous ink composition of any one of Application Examples 1 to 5,
The glycol ether solvent may have a structure represented by the following general formula (1).
R ¹ — (O—R ³ ) _n —O—R ² (1)
^{(R 1} and ^{R 2} represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. However, at least one of ^{R 1} and ^{R 2} is an alkyl group having 1 to 4 carbon atoms .R ^3, the number of carbon atoms (It is an alkylene group of 2 to 3. n is an integer of 1 to 4.)

[Application Example 7]
In the non-aqueous ink composition of any one of Application Examples 1 to 6,
The content of the glycol ether solvent may be 40% by mass or more based on the total mass of the non-aqueous ink composition.

[Application Example 8]
In the non-aqueous ink composition of any one of Application Examples 1 to 7,
As the glycol ether solvent, a glycol ether solvent having an HLB of 10 or more can be contained in an amount of 30% by mass or more based on the total mass of the non-aqueous ink composition.

[Application Example 9]
The non-aqueous ink composition of any one of Application Examples 1 to 8 is
It can be an inkjet non-aqueous ink composition.

FIG. 2 is a perspective view schematically showing a configuration of an ink jet printer that can be used in the present embodiment.

  Hereinafter, preferred embodiments of the present invention will be described. Embodiment described below demonstrates an example of this 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.

  In the present invention, “image” refers to a print pattern formed from a group of dots, and includes text printing and solid printing.

  In the present invention, the “non-aqueous ink composition” is an ink composition in which an organic solvent is a main solvent and water is not a main solvent. Preferably, the content of water in the composition is 3% by mass or less, more preferably 1% by mass or less, still more preferably less than 0.05% by mass, still more preferably less than 0.01% by mass, More preferably, it means less than 0.005% by mass, and most preferably less than 0.001% by mass. Or it is good also as an ink composition which does not contain water substantially. “Substantially not containing” means not intentionally containing.

1. Non-aqueous ink composition A non-aqueous ink composition according to an embodiment of the present invention includes carbon black as a pigment, a lactone solvent, a glycol ether solvent having an HLB value of 8 or more, and an amine as a pigment dispersant. And a pigment derivative introduced with a polar group having no structure. Hereinafter, each component contained in the non-aqueous ink composition according to this embodiment will be described.

1.1. Pigment The non-aqueous ink composition according to this embodiment contains carbon black as a pigment. Although it does not specifically limit as 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), Columbian Chemicals, Regal 400R, 330R, 660R, Mogul L, Monarch 700, 800, 880, 900, 1000, 1100, 1300, 1400, Elftex 12 (all trade names above) , Manufactured by Cabot Corporation).

  The content of the carbon black can be appropriately set as desired, and is not particularly limited. It can be made 25 mass% or less, preferably 1 mass% or more and 10 mass% or less.

1.2. Organic solvent 1.2.1. Lactone solvent The non-aqueous ink composition according to this embodiment contains a lactone solvent. By containing a lactone solvent, a part of the recording surface (preferably a recording surface containing a vinyl chloride resin) is dissolved so that the ink penetrates and dries inside the recording medium, thereby fixing the ink to the recording medium. As a result, the rub resistance of the recorded matter is improved. The lactone solvent has a high ability to dissolve a pigment derivative (synergist) described later. It is presumed that by dissolving the pigment derivative in the ink, the pigment derivative enters between the pigment molecules and between the crystal structures of the pigment, thereby preventing the aggregation of pigment molecules and crystals.

  In the present invention, the “lactone solvent” is a general term for cyclic compounds having an ester group (—CO—O—) in the ring. The lactone solvent is not particularly limited as long as it is included in the above definition, but is preferably a lactone having 2 to 9 carbon atoms. Specific examples of such lactones include α-ethyl lactone, α-acetolactone, β-propiolactone, γ-butyrolactone, σ-valerolactone, δ-valerolactone, ε-caprolactone, ζ-enantiolactone, η -Caprolactone, γ-valerolactone, γ-heptalactone, γ-nonalactone, β-methyl-δ-valerolactone, 2-butyl-2-ethylpropiolactone, α, α-diethylpropiolactone, etc. Among these, γ-butyrolactone is particularly preferable. The lactones exemplified above may be used alone or in combination of two or more.

  The content of the lactone solvent is preferably 2% by mass or more and 50% by mass or less, and more preferably 5% by mass or more and 50% by mass or less with respect to the total mass (100% by mass) of the non-aqueous ink composition. Preferably there is. And an upper limit becomes like this. More preferably, it is 30 mass% or less, More preferably, it is 20 mass% or less, Most preferably, it is 15 mass% or less. The lower limit value is more preferably 7% by mass or more, and further preferably 10% by mass or more. When the content of the lactone solvent is 2% by mass or more, wetting and spreading properties of the ink droplets are improved, and the rub resistance of the recorded matter tends to be further improved. Further, when the content ratio of the lactone solvent is 50% by mass or less, the gloss of the recorded matter tends to be improved. Further, when the content of the lactone solvent is in the above range, the pigment derivative (synergist) can be sufficiently dissolved in the ink, so that the effect of the pigment derivative as a dispersant is easily exhibited.

1.2.2. Glycol ether solvent The non-aqueous ink composition according to this embodiment contains a glycol ether solvent having an HLB value of 8 or more (hereinafter also referred to as “specific glycol ether solvent”). The specific glycol ether solvent has a function of improving the wet-spreading property of the ink, and particularly effectively acts on a recording medium with low ink absorption. As a result, the dot diameter of the droplet can be increased by being attached to the recording medium, and an image with excellent glossiness can be recorded, so that the image quality of the obtained image is improved.

  The lower limit of the HLB value of the specific glycol ether solvent is 8 or more, preferably 10 or more. The upper limit of the HLB value of the specific glycol ether solvent is preferably 20 or less, more preferably 18 or less. When the HLB value is within the above range, the ink wettability can be effectively improved particularly for a recording medium having low ink absorption. Further, by controlling the wettability and dryness with respect to the recording medium, it is possible to reduce the aggregation unevenness and improve the printing quality.

The HLB value in the present invention is expressed by the following formula (2) from 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”). This is a calculated value.
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 specific glycol ether solvent preferably has a structure represented by the following general formula (1).
R ¹ — (O—R ³ ) _n —O—R ² (1)
^{(R 1} and ^{R 2} represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. However, at least one of ^{R 1} and ^{R 2} is an alkyl group having 1 to 4 carbon atoms .R ^3, the number of carbon atoms (It is an alkylene group of 2 to 3. n is an integer of 1 to 4.)

In the general formula (1), R ¹ and R ² represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. 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 isopropyl group, an n-butyl group, an isobutyl group, A sec-butyl group, a tert-butyl group, etc. are mentioned. However, when R ¹ is a hydrogen atom, R ² is not a hydrogen atom. Conversely, when R ² is a hydrogen atom, R ¹ is not a hydrogen atom.

In the general formula (1), R ³ represents an alkylene group having 2 or 3 carbon atoms. Specifically, R ³ represents an ethylene group or a propylene group.

  N in the general formula (1) represents the number of added moles of the oxyalkylene group. From the viewpoint of achieving a balance between the drying property of the recorded matter and the wetting and spreading behavior of the ink on the medium, n is preferably 2 to 4.

  Specific examples of the specific glycol ether solvent include ethylene glycol monomethyl ether, diethylene glycol monomethyl ether, triethylene glycol monomethyl ether, ethylene glycol monoisopropyl ether, diethylene glycol monoisopropyl ether, ethylene glycol monobutyl ether, diethylene glycol monobutyl ether, ethylene glycol mono Glycol monoethers such as isobutyl ether and diethylene glycol monoisobutyl ether; ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, diethylene glycol ethyl methyl ether, diethylene glycol diethyl ether, triethylene glycol dimethyl ether, triethylene glycol Ethyl ether, triethylene glycol ethyl methyl ether, triethylene glycol dibutyl ether, tetraethylene glycol dimethyl ether, tetraethylene glycol diethyl ether, tetraethylene glycol ethyl methyl ether, glycol ethers such as tetraethylene glycol dibutyl ether, and the like.

  The content of the specific glycol ether solvent is preferably 40% by mass or more and more preferably 40% by mass or more and 90% by mass or less with respect to the total mass (100% by mass) of the non-aqueous ink composition. It is particularly preferably 50% by mass to 85% by mass. When the content of the specific glycol ether solvent is 40% by mass or more, wetting and spreading properties of ink droplets may be improved and image smoothness may be improved. In addition, when the content of the specific glycol ether solvent is 90% by mass or less, the drying property may be improved and aggregation unevenness due to excessive wetting and spreading may be reduced.

  As a more preferred embodiment, a glycol ether solvent having an HLB value of 10 or more is contained in an amount of 30% by mass or more, preferably 40% by mass or more, particularly preferably 50% by mass or more, based on the total mass of the non-aqueous ink composition. It is. According to this aspect, a more preferable effect can be obtained in terms of printing unevenness, gloss, dot size, surface drying property, and the like.

1.2.3. Other Solvents The non-aqueous ink composition according to this embodiment may contain a solvent other than the lactone solvent and the specific glycol ether solvent. For example, you may contain solvents, such as glycol ethers, ester, ketones, alcohols, amides, alkanediols, and pyrrolidones other than the solvent illustrated above.

1.3. Pigment dispersant 1.3.1. Pigment Derivative Introduced with Polar Group Not Having Amine Structure The non-aqueous ink composition according to this embodiment contains a pigment derivative having a polar group having no amine structure introduced as a pigment dispersant. This pigment derivative (synergist) is considered to have a structure similar to that of a pigment and thus enter between the pigment molecules and the crystal structure of the pigment. Presumed that pigment derivatives that have entered between pigment molecules or between the crystal structures of pigments have been introduced with polar groups that do not have an amine structure, thus suppressing the aggregation of pigment molecules and crystals and improving the dispersibility of pigments. Is done.

  Thus, the pigment derivative (synergist) has a structure in which a polar group is introduced into the pigment skeleton. Examples of pigment skeletons include azo pigments, phthalocyanine pigments, quinacridone pigments, perylene pigments, isoindoline pigments, benzimidazolone pigments, pyranthrone pigments, thioindigo pigments, and quinophthalone pigments.

The “polar group having an amine structure” means a quaternary ammonium group (—N ⁺ R ¹ R ² R ³ X ⁻ ), an amino group (—NH ₂ , —NHR ⁴ , —NR ⁴ R ⁵ ), an amine skeleton A group in which an atom other than the nitrogen atom constituting the amine skeleton is bonded to phthalocyanine (for example, —CONHR ⁶ , —SO ₂ NHR ⁶ , —OCONHR ⁶ , —CONHCOR ⁶ , —CONHSO ₂ R ^6, etc.) Can be mentioned. R ¹ , R ² , and R ³ each independently represent a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, or the like, and X ⁻ represents a counter ion. R ⁴ and R ⁵ each independently represents a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, or the like. R ⁶ represents a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, or the like. Examples of the substituent when the alkyl group and the aryl group are substituted include a sulfonic acid group, a carboxyl group, and a hydroxyl group.

  On the other hand, the “polar group having no amine structure” refers to a group other than the polar group having the amine structure, and examples thereof include a sulfonic acid group and a carboxyl group.

Among these pigment derivatives, from the viewpoint of carbon black dispersibility and foreign matter generation suppression, a phthalocyanine derivative in which a polar group having no amine structure (such as a sulfonic acid group or a carboxyl group) is introduced into the phthalocyanine pigment skeleton (hereinafter referred to as “the phthalocyanine derivative”) Also referred to as “specific phthalocyanine derivative”). Among the specific phthalocyanine derivatives, a copper phthalocyanine derivative having copper as a central metal is particularly preferable. Examples of the copper phthalocyanine derivative include copper phthalocyanine sulfonate, and Solsperse 12000 (trade name, manufactured by LUBRIZOL) is commercially available.

  When two or more polar groups having no amine structure are introduced per molecule of the pigment derivative, 50% or more of the introduced polar groups (for example, when 10 polar groups are introduced) Is preferably a polar group having no amine structure, and 70% or more (for example, 7 or more when 10 polar groups are introduced) does not have an amine structure. A polar group is more preferable, and 90% or more (for example, 9 or more when 10 polar groups are introduced) is particularly preferably a polar group having no amine structure. Thereby, the dispersibility of the carbon black and the suppression of the generation of foreign matters in the ink become more effective.

  When a phthalocyanine derivative is used as a dispersant for a phthalocyanine pigment (for example, CI Pigment Blue 15: 3), since the structures are similar to each other, the phthalocyanine derivative easily enters between the pigment molecules and between the crystal structures of the pigment. Since it is difficult to detach, foreign matter is hard to be generated (that is, no foreign matter problem occurs). On the other hand, when a phthalocyanine derivative is used as a dispersant for carbon black, since carbon black does not have a phthalocyanine skeleton, the phthalocyanine derivative is easily detached from the carbon black, which may cause a problem of generation of foreign matters. However, by using a pigment derivative (particularly a specific phthalocyanine derivative) into which a polar group not having an amine structure is introduced as a dispersant for carbon black, the pigment derivative can be converted from carbon black by the action of the polar group not having an amine structure. It is assumed that it becomes difficult to detach and the generation of foreign matter is suppressed.

  As described above, the specific phthalocyanine derivative can be suitably used as a dispersant for cyan phthalocyanine pigments or black carbon black. If a specific phthalocyanine derivative is used for a magenta or yellow pigment, the cyan color of the specific phthalocyanine derivative is mixed, and a desired ink color may not be obtained. In the case of carbon black, even if the cyan color of the specific phthalocyanine derivative is mixed, there is little influence on the ink color. Rather, the color can be adjusted using the specific phthalocyanine derivative in order to reduce the yellowness of the carbon black.

  The content of the pigment derivative in which a polar group having no amine structure is introduced is 0.05% by mass or more and 5% by mass or less with respect to the total mass (100% by mass) of the non-aqueous ink composition. Preferably, the upper limit is more preferably 3% by mass or less, and particularly preferably 2% by mass or less. When the content of the pigment derivative is within the above range, the dispersibility of the pigment can be further improved, and the generation of foreign matters derived from the pigment derivative can be further suppressed.

1.3.2. Other Pigment Dispersants The non-aqueous ink composition according to this embodiment may contain a pigment dispersant other than the above pigment derivative. Examples of pigment dispersants other than the above pigment derivatives include resin dispersants.

  A resin dispersant may be used as a main dispersant, and the above pigment derivative may be used as a dispersion aid. According to this aspect, the dispersibility of the pigment can be further improved by the synergistic effect of the resin dispersant and the pigment derivative.

Examples of the resin dispersant include polyvinyl alcohols, polyacrylic acid, acrylic acid-acrylonitrile copolymer, vinyl acetate-acrylic acid ester copolymer, acrylic acid-acrylic acid ester copolymer, and styrene-acrylic acid copolymer. Styrene-methacrylic acid copolymer, styrene-methacrylic acid-acrylic acid ester copolymer, styrene-α-methylstyrene-acrylic acid copolymer, styrene-α-methylstyrene-acrylic acid-acrylic acid ester copolymer Styrene-maleic acid copolymer, styrene-maleic anhydride copolymer, vinyl naphthalene-acrylic acid copolymer, vinyl naphthalene-maleic acid copolymer, vinyl acetate-maleic acid ester copolymer, vinyl acetate-croton Acid copolymers, vinyl acetate-acrylic acid copolymers, and the like Salt. Among these, a copolymer of a monomer having a hydrophobic functional group and a monomer having a hydrophilic functional group, and a polymer composed of a monomer having both a hydrophobic functional group and a hydrophilic functional group are preferable. As the form of the copolymer, any form of a random copolymer, a block copolymer, an alternating copolymer, and a graft copolymer can be used.

  Commercially available products can be used as the resin dispersant, such as Hinoact KF1-M, T-6000, T-7000, T-8000, T-8350P, T-8000E (all manufactured by Takefu Fine Chemical Co., Ltd.), etc. Polyester polymer compound, Solsperse 20000, 24000, 32000, 32500, 33500, 34000, 35200, 37500 (all manufactured by LUBRIZOL), Disperbyk-161, 162, 163, 164, 166, 180, 190, 191, 192, 2091, 2095 (both made by Big Chemie Japan), Floren DOPA-17, 22, 33, G-700 (both made by Kyoeisha Chemical Co., Ltd.), Addisper PB821, PB711 (both made by Ajinomoto Co., Inc.), LP40 0, LP4050, LP4055, POLYMER400,401,402,403,450,451,453 (all manufactured by EFKA Chemicals Co., Ltd.).

  When the resin dispersant is contained, the content thereof is preferably 5 parts by mass or more and 200 parts by mass or less, and more preferably 30 parts by mass or more and 120 parts by mass or less with respect to 100 parts by mass of the pigment. .

1.4. resin
The non-aqueous ink composition according to this embodiment may contain a resin (hereinafter, also referred to as “fixing resin”) for fixing the above-described pigment to a recording medium.

  As fixing resin, acrylic resin, styrene acrylic resin, rosin modified resin, phenol resin, terpene resin, polyester resin, polyamide resin, epoxy resin, vinyl acetate resin, vinyl chloride resin, cellulose acetate butyrate and other fiber resins, Examples include vinyl toluene-α-methylstyrene copolymer resin. Among these, at least one resin selected from the group consisting of acrylic resins and vinyl chloride resins is preferable. By containing these fixing resins, the fixing property to the recording medium can be improved and the abrasion resistance is also improved.

  The solid content of the fixing resin in the non-aqueous ink composition according to this embodiment is preferably 0.05% by mass to 15% by mass, and more preferably 0.1% by mass to 10% by mass. When the content of the fixing resin is within the above range, excellent fixability for a low-absorbency recording medium can be obtained.

<Acrylic resin>
As the acrylic resin, a copolymer made of a conventionally known polymerizable monomer can be used. Examples of the polymerizable monomer include acrylic acid esters such as methyl acrylate, ethyl acrylate, isopropyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate; methyl methacrylate, ethyl methacrylate, isopropyl methacrylate, Methacrylic acid esters such as n-butyl methacrylate, isobutyl methacrylate, t-butyl methacrylate, cyclohexyl methacrylate, 2-ethylhexyl methacrylate; acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, mono maleic acid Carboxy group-containing monomers such as n-butyl, mono-n-butyl fumarate, mono-n-butyl itaconate, hydroxyl group-containing (meth) acrylic acid esters, amide group-containing monomers, glycidyl group-containing monomers, cyano group-containing monomers Hydroxyl-containing allyl compounds may be used tertiary amino group-containing monomer, an alkoxysilyl group-containing monomers alone or in combination with.

  Commercially available products may be used as the acrylic resin, for example, Acrypet MF (trade name, manufactured by Mitsubishi Rayon Co., Ltd., acrylic resin), Sumipex LG (trade name, manufactured by Sumitomo Chemical Co., Ltd., acrylic resin), Paraloid B series, etc. (Trade name, manufactured by Rohm and Haas, acrylic resin), Parapet G-1000P (trade name, manufactured by Kuraray Co., Ltd.). In the present invention, (meth) acrylic acid means both acrylic acid and methacrylic acid, and (meth) acrylate means both acrylate and methacrylate.

<Vinyl chloride resin>
Examples of the vinyl chloride resin include copolymers of vinyl chloride and other monomers such as vinyl acetate, vinylidene chloride, acrylic acid, maleic acid, vinyl alcohol, etc. Among these, vinyl chloride and vinyl acetate can be used. A copolymer containing a derived structural unit (hereinafter also referred to as “vinyl chloride copolymer”) is preferred, and a vinyl acetate copolymer having a glass transition temperature of 60 to 80 ° C. is more preferred.

  The vinyl chloride / vinyl chloride copolymer can be obtained by a conventional method, for example, by suspension polymerization. Specifically, water, a dispersant, and a polymerization initiator are charged into the polymerization vessel and degassed, and then vinyl chloride and vinyl acetate are injected to perform suspension polymerization, or a portion of vinyl chloride and vinyl acetate are injected. Thus, the reaction can be started and suspension polymerization can be performed while the remaining vinyl chloride is injected during the reaction.

  The vinyl chloride / vinegar copolymer preferably contains 70 to 90% by mass of vinyl chloride units as its constitution. If it is the said range, since it melt | dissolves stably in an ink composition, it is excellent in long-term storage stability. Furthermore, the ejection stability is excellent, and excellent fixability to the recording medium can be obtained.

  Further, the vinyl chloride / vinyl acetate copolymer may be provided with other structural units as necessary together with the vinyl chloride unit and the vinyl acetate unit, such as a carboxylic acid unit, a vinyl alcohol unit, and a hydroxyalkyl acrylate unit. Of these, vinyl alcohol units are particularly preferred. It can be obtained by using monomers corresponding to the aforementioned units. Specific examples of monomers that give carboxylic acid units include maleic acid, itaconic acid, maleic anhydride, itaconic anhydride, acrylic acid, and methacrylic acid. Specific examples of the monomer that gives a hydroxyalkyl acrylate unit include, for example, hydroxyethyl (meth) acrylate, hydroxyethyl vinyl ether, and the like. The content of these monomers is not limited as long as the effects of the present invention are not impaired. For example, the monomers can be copolymerized in a range of 15% by mass or less of the total amount of monomers.

  In addition, a commercially available vinyl chloride copolymer may be used. For example, sorbine CN, solvin CNL, solvin C5R, solvin TA5R, sorbine CL, sorbine CLL (manufactured by Nissin Chemical Industry Co., Ltd.) Etc.

Although the average degree of polymerization of these resins is not particularly limited, it is preferably 150 to 1100, more preferably 200 to 750. When the average degree of polymerization of these resins is in the above range, the resin is stably dissolved in the ink composition according to the present embodiment, and thus has excellent long-term storage stability. Furthermore, the ejection stability is excellent, and excellent fixability to the recording medium can be obtained. The average degree of polymerization of these resins is calculated from the specific viscosity measured, and can be determined according to the method for calculating the average degree of polymerization described in “JIS K6720-2”.

  Moreover, the number average molecular weight of these resins is not particularly limited, but is preferably 10,000 to 50,000, and more preferably 12,000 to 42,000. The number average molecular weight can be measured by GPC and can be obtained as a relative value in terms of polystyrene.

1.5. Surfactant The non-aqueous ink composition according to this embodiment may contain a surfactant from the viewpoint of reducing the surface tension and improving the wet spreading property on the recording medium. Examples of the surfactant include a silicon-based surfactant, a fluorine-based surfactant, or a polyoxyethylene derivative that is a nonionic surfactant.

  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.

  When the surfactant is contained, the content thereof can be 0.1% by mass or more and 5% by mass or less with respect to the total mass (100% by mass) of the non-aqueous ink composition.

1.6. Other Components In addition to the above components, the non-aqueous ink composition according to this embodiment includes a chelating agent such as ethylenediaminetetraacetate (EDTA), an antiseptic, a viscosity modifier, a dissolution aid, an antioxidant, and A substance for imparting a predetermined performance such as an antifungal agent can be contained.

1.7. Preparation of Non-Aqueous Ink Composition The non-aqueous ink composition according to this embodiment is obtained by mixing the components described above in an arbitrary order and removing impurities by filtering or the like as necessary. As a method for mixing the components, 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 suitably used. As a filtration method, centrifugal filtration, filter filtration, and the like can be performed as necessary.

1.8. Physical Properties of Non-Aqueous Ink Composition When the non-aqueous ink composition according to this embodiment is used as an inkjet ink, the viscosity (viscosity at 25 ° C.) is preferably 2 mP, for example, by adjusting the composition and formulation.
a · s to 20 mPa · s, more preferably 3 mPa · s to 15 mPa · s. As a result, the ejection stability (e.g., ejection volume stability, flight characteristics of droplets), ejection response (response speed, high frequency compatibility (frequency characteristics), etc.), etc., of the inkjet ink are excellent. it can. In addition, the viscosity of the ink for inkjet can be calculated | required by the measurement based on JISZ8809 using a vibration viscometer.

  In the ink composition according to the present embodiment, the surface tension at 20 ° C. is preferably 20 mN / m or more and 50 mN / m or more, and 25 mN / m or more, from the viewpoint of the balance between the recording quality and the reliability as an inkjet ink. More preferably, it is 40 mN / m or less. 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 wet with ink in an environment of 20 ° C. can do.

2. Inkjet recording method The non-aqueous ink composition described above can be used in an inkjet recording method. This ink jet recording method includes a step (hereinafter also referred to as “step (a)”) in which droplets of the above-described non-aqueous ink composition are ejected from a recording head of an ink jet printer and adhered to a recording medium. Through this step, a recorded matter having an image formed on the recording medium is obtained.

  According to such an ink jet recording method, since the above non-aqueous ink composition is used, an image with excellent generation of foreign matter, excellent ink ejection, and excellent glossiness, aggregation unevenness, and abrasion resistance is recorded. can do.

  In this ink jet recording method, the step (a) is preferably performed on a recording medium heated to 30 ° C. or higher and 50 ° C. or lower. By adhering the non-aqueous ink composition described above to the heated recording medium, the drying property of the ink can be improved.

  In addition, the ink jet recording method may include post-heating (hereinafter also referred to as “step (b)”) for further heating the recording medium after the step (a). By further providing the step (b), the drying property of the ink can be further improved.

  An ink jet recording apparatus that can include the above-described steps includes a mechanism for ejecting the non-aqueous ink composition described above as droplets from a fine nozzle of a recording head and attaching the droplets to a recording medium. Any device can be used as long as it is present. Hereinafter, an ink jet printer having a mechanism capable of heating a recording medium will be described as an example of an ink jet recording apparatus usable in the present embodiment.

  FIG. 1 is a perspective view showing a configuration of an ink jet printer (hereinafter also simply referred to as “printer”) that can be used in the present embodiment. The printer 1 shown in FIG. 1 is a so-called serial printer. A serial printer is a printer in which a recording head is mounted on a carriage that moves in a predetermined direction, and droplets are ejected onto a recording medium when the recording head moves as the carriage moves.

As shown in FIG. 1, a printer 1 includes a carriage 4 on which a recording head 2 is mounted and an ink cartridge 3 is detachably mounted; a platen 5 that is disposed below the recording head 2 and that transports a recording medium P; And a heating mechanism 6 for heating the recording medium, a carriage moving mechanism 7 for moving the carriage 4 in the medium width direction of the recording medium P, and a medium feeding mechanism 8 for conveying the recording medium P in the medium feeding direction. Is. The printer 1 also has a control device CONT that controls the operation of the entire printer 1. The medium width direction is the main scanning direction (head scanning direction). The medium feeding direction is a sub-scanning direction (a direction orthogonal to the main scanning direction).

  The ink cartridge 3 is composed of, for example, four independent cartridges. Each of the four cartridges is filled with the non-aqueous ink composition described above. In the example of FIG. 1, the number of cartridges is four. However, the number of cartridges is not limited to this, and a desired number of cartridges can be mounted.

  The ink cartridge 3 is not limited to the one mounted on the carriage 4 as shown in FIG. 1, but instead is one of the type that is mounted on the housing side of the printer 1 and supplied to the head 2 via the ink supply tube. There may be.

  The carriage 4 is attached in a state of being supported by a guide rod 9 which is a support member installed in the main scanning direction. The carriage 4 is moved in the main scanning direction along the guide rod 9 by the carriage moving mechanism 7. In the example of FIG. 1, the carriage 4 moves in the main scanning direction. However, the present invention is not limited to this, and the carriage 4 may move in the sub scanning direction in addition to the movement in the main scanning direction. .

  As long as the heating mechanism 6 is provided at a position where the recording medium P can be heated, the installation position is not particularly limited. In the example of FIG. 1, the heating mechanism 6 is installed on the platen 5 at a position facing the head 2. Thus, when the heating mechanism 6 is installed at a position facing the head 2, the adhesion position of the droplets on the recording medium P can be reliably heated, so that the droplets adhering to the recording medium P can be efficiently dried. it can.

  The heating mechanism 6 includes, for example, a print heater mechanism that heats the recording medium P in contact with a heat source, a mechanism that irradiates infrared rays or microwaves (electromagnetic waves having a maximum wavelength of about 2,450 MHz), and warm air. A dryer mechanism or the like for spraying can be used.

  The heating of the recording medium P by the heating mechanism 6 is performed before or when the droplets ejected from the nozzle holes (not shown) adhere to the recording medium P. In this way, the droplets attached to the recording medium P can be quickly dried. Control of various heating conditions (for example, heating timing, heating temperature, heating time, etc.) is performed by the control device CONT.

  The heating of the recording medium P by the heating mechanism 6 may be performed so that the recording medium P maintains a temperature range of 30 ° C. or more and 50 ° C. or less from the viewpoint of improving the drying property of the ink and preventing the deformation of the recording medium. preferable. Here, “the temperature at which the recording medium is heated” means the temperature of the recording surface of the recording medium during heating.

  The printer 1 may further have a second heating mechanism (not shown) in addition to the heating mechanism 6. Since the printer 1 includes the second heating mechanism, the above-described step (b) can be performed by the printer 1. The second heating mechanism is installed downstream of the heating mechanism 6 in the conveyance direction of the recording medium P. The second heating mechanism heats the recording medium P after the recording medium P is heated by the heating mechanism 6, that is, after the droplets discharged from the nozzle holes (not shown) adhere to the recording medium P. Is what you do. Thereby, the drying property of the droplets of the non-aqueous ink composition attached to the recording medium P can be further improved. Any of the mechanisms described in the heating mechanism 6 (for example, a dryer mechanism) can be used as the second heating mechanism.

The recording medium P is preferably heated by the second heating mechanism so that the recording medium P maintains a temperature range of 30 ° C. or more and 50 ° C. or less for the same reason as the heating mechanism 6.

  The linear encoder 10 detects the position of the carriage 4 in the main scanning direction with a signal. This detected signal is transmitted to the control device CONT as position information. The control device CONT recognizes the scanning position of the recording head 2 based on the position information from the linear encoder 10, and controls the recording operation (discharge operation) by the recording head 2. Further, the control device CONT is configured to be able to variably control the moving speed of the carriage 4.

The recording medium P is not particularly limited. However, since the non-aqueous ink composition described above is used, even when a low-absorbency recording medium is used, the recorded image has abrasion resistance and drying properties. Becomes better. Here, the “low absorption 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. What is necessary is just to have a property. According to this definition, the “low absorption recording medium” in the present invention includes a non-absorbing recording medium that does not absorb water at all. 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".

  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. The non-aqueous ink composition described above contains a lactone solvent, and the lactone solvent can permeate the ink composition into the recording medium by dissolving the recording surface containing the vinyl chloride resin. . Thereby, the abrasion resistance of images and characters recorded on the recording surface containing the vinyl chloride resin can be further improved. Specific examples of the vinyl chloride resin include polyvinyl chloride, vinyl chloride-ethylene copolymer, vinyl chloride-vinyl acetate copolymer, vinyl chloride-vinyl ether copolymer, vinyl chloride-vinylidene chloride copolymer, vinyl chloride. -Maleic acid ester copolymer, vinyl chloride- (meth) acrylic acid copolymer, vinyl chloride- (meth) acrylic acid ester copolymer, vinyl chloride-urethane copolymer and the like. Note that there are no particular restrictions on the various properties such as thickness, shape, color, softening temperature, and hardness of the low-absorbency recording medium.

3. EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples. However, the present invention is not limited only to these examples. In the examples and comparative examples, “parts” and “%” are based on mass unless otherwise specified.

3.1. Preparation of non-aqueous ink composition Various amounts of organic solvents corresponding to the concentrations shown in Tables 1 and 2 are put into a container for each ink, and mixed and stirred for 30 minutes using a magnetic stirrer. Got.

A part of the obtained mixed solvent was separated, and pigment derivatives (synergists) listed in Tables 1 and 2 were mixed therewith, and then carbon black (trade name “No. 230, manufactured by Mitsubishi Chemical Corporation).
0 ") was added and pre-dispersed using a homogenizer, followed by dispersion treatment with a bead mill filled with zirconia beads having a diameter of 0.3 mm, thereby obtaining a dispersion having an average particle size of 130 nm.

  Separately, a part of the mixed solvent is separated, and sorbine CNL (trade name, manufactured by Nissin Chemical Industry Co., Ltd., vinyl chloride-vinyl acetate copolymer, fixing resin) is added and stirred to dissolve completely. A resin solution was obtained.

  To the obtained dispersion, the remainder of the mixed solvent, BYK-340 (Bic Chemie Japan Co., Ltd., fluorinated surfactant) and the above resin solution were added, and the mixture was further stirred for 1 hour. Each black ink composition shown in Table 1 and Table 2 was obtained by filtering using a PTFE membrane filter. In addition, the numerical value in a table | surface represents the mass%.

Of the components used in the table, the components described by trade names or abbreviations are as follows.
<Pigment>
・ Carbon black (trade name “No. 2300”, manufactured by Mitsubishi Chemical Corporation)
<Pigment derivatives (synergists)>
Solsperse 12000 (trade name, manufactured by LUBRIZOL, a copper phthalocyanine derivative having a sulfonic acid group introduced)
・ Solsperse 5000 (trade name, manufactured by LUBRIZOL, copper phthalocyanine derivative with ammonium salt introduced)
<Organic solvent>
・ Diethylene glycol diethyl ether (trade name “diethyl diglycol”, manufactured by Nippon Emulsifier Co., Ltd.)
・ Diethylene glycol ethyl methyl ether (trade name “Methyl ethyl diglycol”, manufactured by Nippon Emulsifier Co., Ltd.)
・ Tetraethylene glycol dimethyl ether (trade name, manufactured by Kishida Chemical Co., Ltd.)
・ Dipropylene glycol dimethyl ether (trade name “dimethylpropylene diglycol”, manufactured by Nippon Emulsifier Co., Ltd.)
・ Propylene glycol dimethyl ether (trade name “HISOLV MMPOM”, manufactured by Toho Chemical Co., Ltd.)
・ Diethylene glycol dibutyl ether (trade name “Dibutyl Diglycol”, manufactured by Nippon Emulsifier Co., Ltd.)
・ Γ-Butyrolactone (trade name, manufactured by Kanto Chemical Co., Inc., solvent)
・ Σ-valerolactone (trade name, manufactured by Kishida Chemical Co., Ltd., solvent)
・ NMP (trade name, manufactured by Mitsubishi Chemical Corporation, N-methyl-2-pyrrolidone)
・ Examide M100 (trade name, manufactured by Idemitsu Kosan Co., Ltd., amide solvent)
<Fixing resin>
・ Solvine CNL (trade name, manufactured by Nissin Chemical Industry Co., Ltd., vinyl chloride-vinyl acetate copolymer, fixing resin)
<Surfactant>
BYK-340 (Bic Chemie Japan Co., Ltd., fluorinated surfactant)

3.2. Evaluation test Among the following evaluation tests, the evaluation of the abrasion resistance, the glossiness, and the aggregation unevenness was performed under the following conditions. That is, Seiko Epson Corporation was installed in the environmental test chamber by adjusting the temperature and humidity of the environmental test chamber to 25 ° C.-65% RH (relative humidity) using air conditioning equipment and a humidifier. This was carried out using an ink jet printer “SC-S30650” (trade name). The temperature and humidity were measured by a temperature / humidity sensor installed on a casing that was not affected by the heat generated by the inkjet printer itself such as a heater. In each evaluation test, the recording medium was heated at 45 ° C. during the recording and for 1 minute after the recording in the platen and the recording medium discharge portion downstream from the platen.

3.2.1. Ink short-term storage stability Each non-aqueous ink composition was filled in an ink cartridge for an ink-jet printer “SC-S30650” manufactured by Seiko Epson Corporation, and left in a 60 ° C.-80% RH (relative humidity) environment for 5 days. . Thereafter, the ink was taken out, and the viscosity when the temperature of the ink was 20 ° C. was measured with a viscometer (trade name “MCR300”) manufactured by Anton Paar. The amount of change from the initial viscosity (ink temperature at the time of measurement of 20 ° C.) was determined and evaluated according to the following evaluation criteria.
“◯”: The amount of change from the initial viscosity is less than 0.1 mPa · s.
“Δ”: The amount of change from the initial viscosity is 0.1 mPa · s or more and less than 0.5 mPa · s “X”: The amount of change from the initial viscosity is 0.5 mPa · s or more

3.2.2. Long-term storage stability of ink Each non-aqueous ink composition is filled in an ink cartridge for an ink-jet printer “SC-S30650” manufactured by Seiko Epson Corporation, and it is 6 months under a room temperature (RT) -80% RH (relative humidity) environment. I left it for a while. Thereafter, the ink was taken out, and the viscosity when the temperature of the ink was 20 ° C. was measured with a viscometer (trade name “MCR300”) manufactured by Anton Paar. The amount of change from the initial viscosity (ink temperature at the time of measurement of 20 ° C.) was determined and evaluated according to the following evaluation criteria. In addition, the presence or absence of foreign matters in the ink after storage was observed with an electron microscope, and the presence or absence of foreign matters derived from synergists was confirmed to confirm that the occurrence of foreign matters was related to thickening. “◯”: The amount of change from the initial viscosity is less than 0.1 mPa · s.
“Δ”: The amount of change from the initial viscosity is 0.1 mPa · s or more and less than 0.5 mPa · s “X”: The amount of change from the initial viscosity is 0.5 mPa · s or more

3.2.3. Scratch resistance Using the printer, each non-aqueous ink composition of Examples and Comparative Examples was recorded on a glossy polyvinyl chloride sheet (manufactured by Roland DG, model number “SV-G-1270G”) with a recording resolution of 720 × 720 dpi. After printing at 100% density, the printed matter of each example was produced by drying at 25 ° C.-65% RH (relative humidity) for 1 day. Subsequently, based on JISL0849, the dry type test was done with the I type testing machine. Thereafter, the OD of the test cotton fabric was measured with Spectrolino (manufactured by Gretag Macbeth). The evaluation criteria are as follows.
“◯”: OD is less than 0.2.
“Δ”: OD is 0.2 or more and less than 0.25.
"X": OD is 0.25 or more.

3.2.4. Glossiness Using the printer, each non-aqueous ink composition of Examples and Comparative Examples was recorded on a glossy polyvinyl chloride sheet (Roland DG, model number SV-G-1270G) at a recording resolution of 720 × 720 dpi. After solid printing, the printed matter was produced by drying at 25 ° C.-65% RH (relative humidity) for 1 day. And 20 degree glossiness of the solid printing part was measured in MULTI GLOSS 268 (made by Konica Minolta Co., Ltd.). The evaluation criteria are as follows. When the glossiness is excellent, there is an advantage that the same glossiness as that of the recording medium itself can be obtained on the recorded matter, particularly in a recording medium having glossiness such as a film.
“◯”: 35 or more.
“△”: Less than 35.

3.2.5. Aggregation unevenness Using the printer, each non-aqueous ink composition of the example and the comparative example was solid on a PVC banner sheet (manufactured by 3M, model number IJ51 (polyvinyl chloride)) at a 100% concentration and a recording resolution of 720 × 720 dpi. After printing, it was dried at 25 ° C.-65% RH (relative humidity) for 60 minutes. Thereafter, the recording surface was observed visually and using an optical microscope. The evaluation criteria are as follows.
“◯”: Unevenness is not seen in the pattern.
“Δ”: Some unevenness is observed in a part of the pattern.
“×”: Unevenness is observed in the entire pattern.

3.3. Evaluation results The results of the above evaluation tests are shown in Tables 1 and 2 below.

According to the non-aqueous ink compositions according to the present invention (Examples 1 to 9), even when carbon black is used as a pigment, generation of foreign matters derived from a pigment derivative (synergist) due to moisture absorption after long-term storage. It was found that the viscosity change could be reduced while being suppressed (that is, the storage stability was excellent). It was also found that the non-aqueous ink composition according to the present invention can record an image having excellent glossiness, uneven aggregation, and abrasion resistance.

  According to Comparative Example 1 and Comparative Example 9, when Solsperse 5000 (a synergist having a polar group having an amine structure introduced) is used as a dispersant, a foreign substance derived from a synergist may be generated due to moisture absorption after long-term storage. all right. Further, as in Comparative Example 9, even when a highly hydrophobic glycol ether solvent was added to improve the overall hydrophobicity, generation of foreign substances derived from synergists due to moisture absorption after long-term storage could not be suppressed.

  According to Comparative Example 2, it was found that when a synergist as a dispersant was not contained, it was difficult to disperse carbon black, and the ink was not excellent in short-term and long-term storage.

  According to Comparative Example 3, when no lactone solvent was contained, no foreign matter derived from synergists due to moisture absorption after long-term storage was observed, but a recorded material having excellent abrasion resistance was obtained.

  According to Comparative Example 4 and Comparative Example 5, when NMP or an amide solvent is added instead of the lactone solvent, the gloss is slightly lowered while the abrasion resistance is good, and the synergist is obtained by long-term storage. It turned out that the foreign material which originates occurs.

  According to Comparative Examples 6 to 8, when only a glycol ether solvent having an HLB value of less than 8 was generated, no generation of foreign substances derived from synergists due to moisture absorption after long-term storage was observed, but glossiness As a result, a recorded material having no excellent aggregation unevenness was obtained.

  In addition, as shown in Reference Example 1, C.I. I. It was found that when Pigment Blue 15: 3 was dispersed with a phthalocyanine derivative, that is, when the same series pigment was used, generation of foreign substances derived from synergists due to moisture absorption after long-term storage was unlikely to occur.

  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.

DESCRIPTION OF SYMBOLS 1 ... Printer, 2 ... Recording head, 3 ... Ink cartridge, 4 ... Carriage, 5 ... Platen, 6 ... Heating mechanism, 7 ... Carriage moving mechanism, 8 ... Medium feed mechanism, 9 ... Guide lot, 10 ... Linear encoder, P …recoding media

Claims (9)

Carbon black as a pigment,
A lactone solvent,
A glycol ether solvent having an HLB value of 8 or more;
As a pigment dispersant, a pigment derivative introduced with a polar group having no amine structure,
A non-aqueous ink composition.   The non-aqueous ink composition according to claim 1, wherein the pigment derivative is a phthalocyanine derivative.   The non-aqueous ink composition according to claim 1 or 2, wherein a content of the pigment derivative is 0.05% by mass or more and 5% by mass or less with respect to a total mass of the non-aqueous ink composition.   The non-aqueous ink composition according to any one of claims 1 to 3, wherein the lactone solvent has 2 to 9 carbon atoms.   The non-aqueous ink according to any one of claims 1 to 4, wherein a content of the lactone solvent is 5% by mass or more and 50% by mass or less with respect to a total mass of the non-aqueous ink composition. Composition. The non-aqueous ink composition according to claim 1, wherein the glycol ether solvent has a structure represented by the following general formula (1).
R ¹ — (O—R ³ ) _n —O—R ² (1)
^{(R 1} and ^{R 2} represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. However, at least one of ^{R 1} and ^{R 2} is an alkyl group having 1 to 4 carbon atoms .R ^3, the number of carbon atoms (It is an alkylene group of 2 to 3. n is an integer of 1 to 4.)   The non-aqueous ink composition according to any one of claims 1 to 6, wherein a content of the glycol ether solvent is 40% by mass or more based on a total mass of the non-aqueous ink composition.   8. The glycol ether solvent according to claim 1, wherein the glycol ether solvent having an HLB of 10 or more is contained in an amount of 30% by mass or more based on the total mass of the non-aqueous ink composition. Non-aqueous ink composition.   The non-aqueous ink composition according to any one of claims 1 to 8, which is an inkjet non-aqueous ink composition.

Images