JP2019210472A - Aqueous coloring liquid, inkjet ink, and writing instrument ink - Google Patents

Abstract

To provide an aqueous coloring liquid containing cellulose nanofiber having excellent storage stability and colored substantially uniformly as an inkjet ink and a writing instrument ink.SOLUTION: An aqueous coloring liquid at least contains an aqueous medium, and cellulose nanofiber dyed with a compound represented by the general formula (1) in the figure. [In general formula (1), R, Rand Reach represent an alkyl group; and Rand Reach represent an alkyl group, aryl group or acyl group, or Rand Rrepresent alkylenes in a case that Rand Rare coupled to form a ring.]SELECTED DRAWING: None

Description

  The present invention relates to an aqueous coloring liquid, an ink-jet ink, and a writing instrument ink.

  In recent years, attention has been focused on cellulose nanofibers that can be obtained by chemically or mechanically defibrating plant fibers, and researches are actively conducted in various fields.

  In addition, in writing instruments (particularly ballpoint pens), user demands for writing taste, writing (initial writing performance), and stabilization of handwriting are increasing rapidly.

  And the example which utilized the cellulose nanofiber as a writing instrument use is also reported (patent documents 1-2).

JP 2017-105907 A JP 2017-125135 A

  Since the dye has low compatibility with the cellulose nanofiber, the dye and the cellulose nanofiber are each aggregated, and there is a problem that the cellulose nanofiber is not uniformly dyed with the dye. Moreover, the aqueous | water-based coloring liquid containing the cellulose nanofiber of such a nonuniform dyeing | staining state had the subject that it was inferior in storage stability.

  The present invention relates to an aqueous coloring liquid characterized by containing at least cellulose nanofibers dyed with a compound represented by the general formula (1).

[In General Formula (1), R ₁ and R ₂ each independently represent an alkyl group, R ₃ represents an alkyl group, and R ₄ and R ₅ each independently represent an alkyl group, aryl A group or an acyl group, or R ₄ and R ₅ are combined to form a ring, in which case R ₄ and R ₅ represent alkylene. ]

  Since the compound represented by the general formula (1) and cellulose nanofiber exhibit high compatibility, it is possible to provide an aqueous coloring liquid containing cellulose nanofiber that is colored in a nearly uniform state and excellent in storage stability. it can. Furthermore, an ink-jet ink and a writing instrument ink excellent in storage stability can be provided.

  Hereinafter, embodiments of the present invention will be described in detail.

  Conventionally, the compatibility between the cellulose nanofiber and the dye has been low. Therefore, dye molecules or cellulose nanofibers are strongly aggregated.

  Since the compound represented by the following general formula (1) used in the present invention is highly compatible with cellulose nanofibers, the interaction between the compounds in the molecule or between the molecules is suppressed, and aggregation can be controlled. it can. As a result, an aqueous colored liquid having excellent storage stability, including cellulose nanofibers colored in a nearly uniform state. Furthermore, it becomes the ink for inkjet and writing instruments excellent in storage stability.

  First, the compound represented by the general formula (1) will be described.

[In General Formula (1), R ₁ and R ₂ each independently represent an alkyl group, R ₃ represents an alkyl group, and R ₄ and R ₅ each independently represent an alkyl group, aryl A group or an acyl group, or R ₄ and R ₅ are combined to form a ring, and in this case, R ₄ and R ₅ represent alkylene. ]

In general formula (1), the alkyl group in R ₁ and R ₂ is not particularly limited, and examples thereof include substituted or unsubstituted alkyl groups having 1 to 20 carbon atoms. Examples of the substituent include an alkoxy group, and an unsubstituted alkyl group is preferable. Specific examples of the unsubstituted alkyl group having 1 to 20 carbon atoms include methyl, ethyl, n-propyl, iso-propyl, n-butyl, sec-butyl, tert-butyl, and octyl. And linear, branched or cyclic alkyl groups such as a group, dodecyl group, nonadecyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group, methylcyclohexyl group, 2-ethylpropyl group, 2-ethylhexyl group. Among these, since it is highly compatible with cellulose nanofibers, a substituted or unsubstituted alkyl group having 1 to 8 carbon atoms is preferable, and a branched alkyl group such as a 2-ethylhexyl group is more preferable.

In general formula (1), the alkyl group for R ₃ is not particularly limited, and examples thereof include linear or branched alkyl groups having 1 to 8 carbon atoms. Specifically, methyl group, ethyl group, n-propyl group, iso-propyl group, n-butyl group, iso-butyl group, 2-methylbutyl group, 2,3,3-trimethylbutyl group, octyl group, etc. Can be mentioned. Among these, a methyl group, an n-butyl group, a 2-methylbutyl group, and a 2,3,3-trimethylbutyl group are preferable because the compatibility with cellulose nanofibers is high, and the effects of the present invention are easily obtained. A methyl group is preferred.

In general formula (1), the alkyl group in R ₄ and R ₅ is not particularly limited, and examples thereof include substituted or unsubstituted alkyl groups having 1 to 20 carbon atoms. Examples of the substituent include an alkoxy group, and an unsubstituted alkyl group is preferable. Specific examples of the unsubstituted alkyl group having 1 to 20 carbon atoms include methyl, ethyl, n-propyl, iso-propyl, n-butyl, sec-butyl, tert-butyl, and octyl. Group, dodecyl group, nonadecyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group, methylcyclohexyl group, 2-ethylpropyl group, 2-ethylhexyl group, etc., linear, branched or cyclic, having 1 to 20 carbon atoms An alkyl group is mentioned. Among these, an unsubstituted alkyl group having 1 to 4 carbon atoms is preferable. Examples of the alkylene formed by combining R ₄ and R ₅ include pentylene.

In the general formula (1), the aryl group in R ₄ and R ₅ is not particularly limited, and examples thereof include substituted or unsubstituted aryl groups having 6 to 10 carbon atoms. Examples of the substituent include an alkyl group and an alkoxy group. In addition, when it has a substituent, the carbon number includes the carbon number of the substituent. One or more substituents may be used. Specific examples of the substituted or unsubstituted aryl group having 6 to 10 carbon atoms include a phenyl group, a 4-methylphenyl group, and a 4-methoxyphenyl group.

In general formula (1), the acyl group in R ₄ and R ₅ is not particularly limited, and examples thereof include substituted or unsubstituted acyl groups having 1 to 30 carbon atoms. Examples of the substituent include an alkoxy group, and an unsubstituted acyl group is preferable. Specifically, formyl group; unsubstituted alkylcarbonyl group having 2 to 30 carbon atoms such as acetyl group, propionyl group, and pivaloyl group; unsubstituted arylcarbonyl group having 7 to 30 carbon atoms such as benzoyl group and naphthoyl group A heterocyclic carbonyl group such as a 2-pyridylcarbonyl group and a 2-furylcarbonyl group; Among these, an acetyl group, a pivaloyl group, or a benzoyl group is preferable, and an acetyl group or a benzoyl group is more preferable from the viewpoint of improving the saturation and dispersibility under high concentration conditions. Since the combination of R ₄ and R ₅ is highly compatible with cellulose nanofibers, it is particularly preferable that one is a combination of an alkyl group and the other is an acyl group. In this case, a remarkable effect is obtained.

  The compound represented by the general formula (1) can be synthesized with reference to a known method described in WO2014 / 034094.

  The compound represented by the general formula (1) has cis-trans isomers, all of which are within the scope of the present invention, and the compound represented by the general formula (1) is a mixture thereof. Also good.

  Although the example of a compound represented by General formula (1) is shown below, it is not limited to these.

  The compound represented by General formula (1) may be used individually by 1 type, and may use 2 or more types together. Among the above compounds, compounds (1), (2), (4), (5), (6), (7), (8), and (10) are particularly preferable.

  It is preferable that the compounding quantity of the compound represented by General formula (1) is 0.1-50 mass parts per 100 mass parts of aqueous medium contained in an aqueous coloring liquid. More preferably, it is 1-25 mass parts, More preferably, it is 2-10 mass parts.

  In addition, other known colorants may be used in combination with the aqueous coloring liquid.

  Colorants (dyes and pigments) that can be used in combination are determined within a range that does not impair the properties in various applications.

  The dye that can be used in combination is not particularly limited. For example, acid dyes, basic dyes, metal complex dyes, salt-forming dyes, azine dyes, condensed azo compounds, azo metal complexes, diketopyrrolopyrrole compounds, anthraquinones Examples thereof include compounds, quinacridone compounds, naphthol compounds, benzimidazolone compounds, thioindigo compounds, perylene compounds, methine compounds, allylamide compounds, phthalocyanine dyes, triphenylmethane dyes, basic dye lake compounds, and the like.

  As specific examples, NIGROSIN BASE EX-BP, NUBIAN BLACK PA-2800, VALIFAST BLACK 1805, VALIFAST BLACK 1807, VALIFAST BLACK 1815, VALIFAST BLACK 1821, Oil Blue 61313, VALIFASTD13 1360, VALIFAST BLUE 1601, VALIFAST BLUE 1605, VALIFAST BLUE 1621, VALIFAST YELLOW 1101, VALIFAST YELLOW 1151 (above, manufactured by Orient Chemical Industry Co., Ltd.), Aizon Spiron lue 2BNH, Aizon Spilon Red C-GH, Aizon Spilon Red C-BH, Aizon Spilon Yellow C-GHN new, Aizon Spilon Yellow GRLH special, Aizon S. P. T.A. And Blue-121 (manufactured by Hodogaya Chemical Co., Ltd.).

  The pigment that can be used in combination is not particularly limited, for example, carbon black, aniline black, titanium dioxide pigment, phthalocyanine, quinacridone, diketopyrrole, azo, dioxane, quinophthalone, triphenylmethane, perylene, perinone, metallic pigment, Examples include pearl pigments, fluorescent pigments, and phosphorescent pigments.

  Specific examples include FUJI FAST RED 8800 (C.I. Pigment Red 254), FUJI FAST RED 2200 (C.I. Pigment Red 170) (manufactured by Fuji Pigment Co., Ltd.), and the like.

  The pigment preferably has an average particle size of 30 nm to 700 nm after being dispersed in the medium.

  The blending amount of the pigment is preferably 0.5 to 25 parts by mass, more preferably 0.5 to 20 parts by mass with respect to 100 parts by mass of the aqueous medium contained in the aqueous coloring liquid.

[Aqueous coloring liquid]
The aqueous coloring liquid of the present invention contains cellulose nanofibers dyed with a compound represented by the general formula (1).

  In the present invention, any material generally known as cellulose nanofiber can be used without any particular limitation. For example, it is obtained by chemically and / or mechanically defibrating plant fibers, and is an ultrafine fiber having an average width of about several nm to 20 nm and an average length of about 0.5 μm to several μm. is there.

  As the material containing cellulose fiber, wood, bamboo, kenaf, hemp, jute, wood pulp, waste paper, crystalline cellulose, crop residue, regenerated pulp and other plants, sea squirt animals, algae, microorganisms and the like can be used.

  Examples of the apparatus for performing the defibrating treatment include a rotary shear type homogenizer, a high-pressure homogenizer, a high-pressure homogenizer, a ball mill, a sand mill, an attritor, a high-pressure counter-impact disperser, a grinder, and a conical refiner.

  Cellulose fibers are commercially available, and they can also be used. Examples of commercially available products include Rheocrista I-2AX, CNF 03, CNF 04 (Daiichi Kagaku Kogyo Co., Ltd.), ELLEX-S (Daiou Paper Co., Ltd.) and na norest-S (Chuetsu Pulp Kogyo Co., Ltd.).

  The size (fiber diameter) of these cellulose nanofibers varies depending on the type of cellulose nanofiber. In addition, the fiber diameter is selected in a suitable range from the viewpoint of thickening action, stability over time, color developability, etc. within the range not impairing the properties in various applications.

  The blending amount of the cellulose nanofibers is preferably 0.001 to 40 parts by mass, more preferably 0.01 to 10 parts by mass, and still more preferably 0 per 100 parts by mass of the aqueous medium contained in the aqueous coloring liquid. It is preferable that it is 0.05-5 mass parts.

  In the aqueous coloring liquid, water or a mixed medium of water and a water-soluble organic solvent can be used as an aqueous medium in which the compound represented by the general formula (1) is dispersed.

  The method for dyeing cellulose nanofibers using the compound represented by the general formula (1) is not particularly limited. For example, after contacting the cellulose nanofibers with the compound represented by the general formula (1) in an aqueous medium, heating or oxidation treatment is performed as necessary, and then the medium is distilled to remove the dye. Cellulose nanofibers can be obtained. When contacting, a pH adjuster, a developer, a dispersant, etc. may be added.

  The aqueous coloring liquid may be the same as that used when dyeing cellulose nanofibers, or the dried cellulose nanofibers may be taken out and dispersed again in an aqueous medium or the like. Good.

  The aqueous coloring liquid can be suitably used as a material for inkjet ink, printing ink, paint, or writing instrument ink.

[Inkjet ink]
Next, the inkjet ink will be described.

  An inkjet ink means an ink used in an inkjet image forming method / apparatus. The inkjet ink contains an aqueous medium and cellulose nanofibers dyed with the compound represented by the general formula (1). In addition, additives may be added as appropriate as long as the properties in various applications are not impaired. The additive will be described later.

  In the case of an inkjet ink, it is preferable to use a mixture of water and a water-soluble organic solvent as the aqueous medium. As the water-soluble organic solvent to be contained in the aqueous medium, for example, alcohol, polyhydric alcohol, polyglycol, glycol ether, nitrogen-containing polar solvent, sulfur-containing polar solvent and the like can be used. Specific examples include ethylene glycol, diethylene glycol, triethylene glycol, 3-methyl-1,3-butanediol, 1,3-butanediol, polyethylene glycol, glycerin, ethylene glycol monomethyl ether, and diethylene glycol monomethyl ether. These water-soluble organic solvents contribute to maintaining the moisture retention of the inkjet ink, improving the solubility of the coloring material, and effectively penetrating the inkjet ink into the recording paper. In the aqueous medium in the inkjet ink, the ratio (mass basis) of water and the water-soluble organic solvent is preferably water / water-soluble organic solvent = 9/1 to 1/9. More preferably, it is 8/2 to 2/8, and further preferably 7/3 to 3/7. In this way, the dispersibility or solubility of the colorant containing the compound (1) in the ink can be improved. In particular, when it is used for ink jet recording, it has a viscosity for stable ink ejection and can prevent clogging at the nozzle tip.

  As a component of the inkjet ink, a chemically synthesized surfactant such as an ionic surfactant, a nonionic surfactant, or a polymer surfactant can be used. There is no restriction | limiting in particular in the kind of surfactant, It can use individually or in combination. The total surfactant content in the inkjet ink is preferably 0.5 to 20 parts by mass per 100 parts by mass of the aqueous medium.

  Examples of the ionic surfactant include aliphatic monocarboxylates, polyoxyethylene alkyl ether carboxylates; N-acyl sarcosine salts, N-acyl glutamates, dialkyl sulfosuccinates; alkane sulfonates, alpha olefins. Sulfonate, linear or branched alkylbenzene sulfonate, naphthalene sulfonate formaldehyde condensate, alkyl naphthalene sulfonate; N-methyl-N-acyl taurate; alkyl sulfate, polyoxyethylene alkyl ether sulfate, Fatty acid sulfate ester salts; anionic surfactants such as alkyl phosphates, polyoxyethylene alkyl ether phosphates, polyoxyethylene alkyl phenyl ether phosphates; alkylamine salts, chloride, bromide or alkyl iodide Cationic surfactants such as diammonium chloride, bromide or bromide or dialkyldimethylammonium iodide, alkylbenzalkonium chloride, alkylpyridinium chloride; alkylbetaines, fatty acid amidopropylbetaines, 2-alkyl-N-carboxymethyl-N- Examples include amphoteric surfactants such as hydroxyethylimidazolinium betaine, alkyl or dialkyldiethylenetriaminoacetic acid, and alkylamine oxide.

  Nonionic surfactants include glycerin fatty acid ester, sorbitan fatty acid ester, sucrose fatty acid ester; polyoxyethylene alkyl ether, polyoxyethylene alkylphenyl ether, polyoxyethylene polyoxypropylene glycol; fatty acid polyethylene glycol, fatty acid polyoxy Examples include ethylene sorbitan and fatty acid alkanolamide.

  Examples of the polymer surfactant include polyacrylate, styrene-acrylic acid copolymer salt, vinyl naphthalene-acrylic acid copolymer salt, styrene-maleic acid copolymer salt, vinyl naphthalene-maleic acid copolymer salt And anionic polymers such as polyphosphoric acid; nonionic polymers such as polyvinyl alcohol, polyvinyl pyrrolidone and polyalkylene glycol.

  The pH of the inkjet ink is not particularly limited, but is preferably in the range of pH 4.0 to 11.0 for ease of handling. In the case of preparing an ink jet ink, a moisturizing solid content such as urea, a urea derivative, or trimethylolpropane may be used as an ink component in order to maintain the moisturizing property of the ink. In general, the content of moisturizing solids such as urea, urea derivatives, and trimethylolpropane in the ink is preferably 0.1 to 20.0% by mass, more preferably 3.0 to 10.0% of the total ink. % By mass.

  Furthermore, in the case of an inkjet ink, in addition to the above-described components, if necessary, a pH adjuster, a rust inhibitor, a preservative, a fungicide, an antioxidant, a reduction inhibitor, an evaporation accelerator, Various additives such as a chelating agent and a water-soluble polymer may be contained.

  The ink-jet ink of the present invention is particularly preferably used for an ink-jet printer that ejects droplets by the action of thermal energy.

  The amount of the compound represented by the general formula (1) and the cellulose nanofiber in the inkjet ink is the same as the amount in the aqueous coloring liquid.

[Ink for writing instruments]
Next, the writing instrument ink according to the present invention will be described.

  The ink for writing instruments contains an aqueous medium and the cellulose nanofiber dye | stained with the compound represented by General formula (1).

  When the ink for writing instruments is used, it is preferable to use a mixture of water and a water-soluble organic solvent as the aqueous medium. As the water-soluble organic solvent to be contained in the aqueous medium, for example, alcohol, polyhydric alcohol, polyglycol, glycol ether, nitrogen-containing polar solvent, sulfur-containing polar solvent and the like can be used. Specific examples include ethylene glycol, diethylene glycol, triethylene glycol, 3-methyl-1,3-butanediol, 1,3-butanediol, polyethylene glycol, glycerin, ethylene glycol monomethyl ether, and diethylene glycol monomethyl ether. These water-soluble organic solvents contribute to maintaining the moisture retention of the writing instrument ink, improving the solubility of the coloring material, and effectively penetrating the writing instrument ink into the recording paper. In the aqueous medium in the writing instrument ink, the ratio (mass basis) of water and the water-soluble organic solvent is preferably water / water-soluble organic solvent = 9/1 to 1/9. More preferably, it is 8/2 to 2/8, and further preferably 7/3 to 3/7. In this way, the dispersibility or solubility of the colorant containing the compound (1) in the ink can be improved.

  Further, the ink for writing instruments can be suitably used for water-based ballpoint pens, gel inks, water-based ballpoint pen inks, and the like, and within a range that does not impair the properties in various applications, dispersants, lubricants, pH adjusters, rust inhibitors, preservatives Alternatively, additives such as antibacterial agents may be added as appropriate. The additive will be described later.

  The ink for writing instruments can be manufactured by a well-known method.

  For example, it can be obtained by blending the aqueous coloring liquid of the present invention, resin, and, if necessary, other colorants and additives in an appropriate temperature range, and stirring and mixing such as a mixer, roll, homogenizer, and disper. Further, a media type dispersing machine such as a rotary shearing type homogenizer, a ball mill, a sand mill, an attritor, or the like, and a high-pressure opposed collision type dispersing machine can also be used.

  The ink for writing instruments may contain other pigments, water-soluble solvents, and the like.

  Although it does not specifically limit as a pigment which can be used together, It can select from the inorganic type and organic type pigments conventionally used for writing instruments, such as a water-based ball-point pen.

  Examples of inorganic pigments include carbon black and metal powder.

  Examples of organic pigments include azo pigments, phthalocyanine pigments, perylene pigments, quinacridone pigments, and the like. Content is 0.1-50 mass parts per 100 mass parts of aqueous media, Preferably, it can use in the range of 0.5-30 mass parts.

  When a pigment is used in combination, a dispersant is preferably used. As the dispersant, an ionic surfactant, a nonionic surfactant, a polymer surfactant, a water-soluble resin, or the like is used as long as the properties in the application are not impaired.

  The lubricant is not particularly limited, and examples thereof include nonionic compounds such as fatty acid esters of polyhydric alcohols, higher fatty acid esters of sugars, and alkyl phosphates, alkyl sulfonates of higher fatty acid amides, and alkyl allyl sulfones. Examples thereof include anionic compounds such as acid salts, derivatives of polyalkylene glycol, fluorine-based surfactants, and polyether-modified silicones.

  The pH adjuster is not particularly limited, but examples thereof include sodium hydroxide, urea, monoethanolamine, diethanolamine, triethanolamine, sodium tripolyphosphate, sodium carbonate, alkali metal salts of phosphoric acid, hydroxide Sodium etc. are mentioned. For example, the pH is preferably adjusted to 4 to 11 and more preferably 5 to 10 from the viewpoint of usability, safety, and stability of the ink itself.

  The rust inhibitor is not particularly limited, and examples thereof include benzotriazole, tolyltriazole, dicyclohexylammonium nitrite, diisopropylammonium nitrite, saponin, and phosphate ester compounds.

  The antiseptic or antibacterial agent is not particularly limited, and examples thereof include phenol, sodium benzoate, benzimidazole compounds, and sodium omadin.

  The amount of the compound represented by the general formula (1) and the cellulose nanofiber in the writing instrument ink is the same as the amount in the aqueous coloring liquid.

  EXAMPLES Hereinafter, although an Example and a comparative example are given and this invention is demonstrated further in detail, this invention is not limited to these Examples. In the text, “parts” and “%” represent “parts by mass” and “% by mass” unless otherwise specified.

The compound represented by the general formula (1) was synthesized by a known method, and identified by ¹ H nuclear magnetic resonance spectroscopy ( ¹ H-NMR) apparatus (ECA-400, manufactured by JEOL Ltd.), and LC / TOF MS apparatus (LC / MSD TOF, manufactured by Agilent Technologies) was used.

<Example 1>
After adding 5 parts of the compound (1), 1 part of methanol, and 0.5 part of cellulose nanofiber (Reocrista I-2AX), 99 parts of ion-exchanged water was added. The mixture was heated to an internal temperature of 80 ° C. and stirred for 2 hours while removing methanol. After allowing to cool to room temperature, a dispersion process was performed for 5 minutes with a homogenizer to prepare an aqueous colored liquid (1) containing cellulose nanofibers dyed with the compound (1).

<Examples 2 to 19 and Comparative Examples 1 to 12>
In Example 1, aqueous coloring liquids (2) to (19) containing cellulose nanofibers dyed with compound (1) by the same operation except that the compounds and cellulose nanofibers were changed to those shown in Table 1. And the comparative example aqueous coloring liquid (1)-(12) was created.

  Comparative compounds (1) and (2) are shown below. Moreover, Daiwa IJ Red 311H (made by Daiwa Kasei Co., Ltd.) was used for the comparative compound (3).

[Evaluation of easy dyeing]
The aqueous colored liquids (1) to (19) obtained above and the comparative aqueous colored liquids (1) to (12) were applied to thick-coated mat coated paper for inkjet by the bar coating method (Bar No. 3). It applied and it was set as the image sample. Using the obtained image samples, the ease of dyeing was evaluated as follows. About the image sample, the presence or absence of the aggregate was observed using the phase-contrast microscope (BX53, the product made by OLYMPUS). It was judged that the smaller the aggregate, the easier it was to dye.
A: There is no aggregate in the image sample.
B: Slight aggregates are generated in the image sample.
C: Aggregates are generated in the image sample.

[Storage stability evaluation]
20 mL of the aqueous coloring liquid obtained above was added to a 50 mL sample bottle, sealed, and allowed to stand for 1 month under low temperature (0 ° C.) and high temperature (60 ° C.) conditions. About the aqueous coloring liquid after leaving, the presence or absence of the aggregate was observed using the phase-contrast microscope (BX53, product made by OLYMPUS). It was judged that the smaller the aggregate, the better the storage stability.
Storage Stability Evaluation Criteria of Aqueous Coloring Liquid A: There is no aggregate in the aqueous coloring liquid.
B: Slight aggregates are generated in the aqueous coloring liquid.
C: Aggregates are generated in the aqueous coloring liquid.

  In the table, Reocrista I-2AX, CNF 03, CNF 04 are available from Daiichi Kagaku Kogyo, ELLEX-S is available from Daio Paper, and na norest-S is from Chuetsu Pulp It is available.

<Example 20>
69.5 parts of the aqueous coloring liquid produced in Example 6, 1 part of acetylenol EH (manufactured by Kawaken Fine Chemical Co., Ltd.), 7.5 parts of ethylene glycol, 7.5 parts of glycerin, and 7.5 parts of urea Then, 14 parts of ion exchange water was added. And these components were fully stirred and dissolved, and the inkjet ink (A) was created.

<Comparative Example 13>
In Example 20, a comparative inkjet ink (B) was prepared in the same manner as in Example 20, except that the aqueous colored liquid produced in Comparative Example 2 was used instead of the aqueous colored liquid produced in Example 6. did.

[Evaluation]
Inkjet ink (A) and comparative inkjet ink (B) were each added in a 50 mL sample bottle, sealed, and allowed to stand at 60 ° C. for 1 month. About the ink-jet ink after being allowed to stand, the presence or absence of aggregates was observed using a phase contrast microscope (BX53, manufactured by OLYMPUS). Aggregates were not confirmed in the inkjet ink (A), whereas aggregates were confirmed in the comparative inkjet ink (B). The ink-jet ink of the present invention was excellent in storage stability because generation of aggregates was suppressed.

<Example 21>
46 parts of the aqueous coloring liquid prepared in Example 6, 1.4 parts of triethanolamine, 0.2 part of benzotriazole, 17 parts of propylene glycol, 0.4 part of phosphate ester, and 35 parts of ion-exchanged water were mixed. Then, these components were sufficiently stirred and dissolved to prepare a writing instrument ink (C).

<Comparative example 14>
In Example 21, a writing instrument ink (D) was prepared in the same manner as in Example 21, except that the aqueous colored liquid produced in Example 6 was changed to the aqueous colored liquid produced in Comparative Example 2.

[Evaluation]
20 mL of the writing instrument ink (C) and comparative writing instrument ink (D) were added to each 50 mL sample bottle, sealed, and allowed to stand for one month under low temperature (0 ° C.) and high temperature (60 ° C.) conditions. About the ink for writing instruments after leaving, the presence or absence of the aggregate was observed using the phase-contrast microscope (BX53, the product made by OLYMPUS). Aggregates were not confirmed in the writing instrument ink (C), whereas aggregates were confirmed in the comparative writing instrument ink (D). The ink for a writing instrument of the present invention was excellent in storage stability because generation of aggregates was suppressed.

Claims (3)

An aqueous coloring liquid comprising an aqueous medium and cellulose nanofibers dyed with a compound represented by the general formula (1).

[In General Formula (1), R ₁ and R ₂ each independently represent an alkyl group, R ₃ represents an alkyl group, and R ₄ and R ₅ each independently represent an alkyl group, aryl A group or an acyl group, or R ₄ and R ₅ are combined to form a ring, in which case R ₄ and R ₅ represent alkylene. ] An inkjet ink comprising an aqueous medium and cellulose nanofibers dyed with a compound represented by the general formula (1).

[In General Formula (1), R ₁ and R ₂ each independently represent an alkyl group, R ₃ represents an alkyl group, and R ₄ and R ₅ each independently represent an alkyl group, aryl A group or an acyl group, or R ₄ and R ₅ are combined to form a ring, in which case R ₄ and R ₅ represent alkylene. ] An ink for a writing instrument comprising an aqueous medium and cellulose nanofibers dyed with a compound represented by the general formula (1).

[In General Formula (1), R ₁ and R ₂ each independently represents an alkyl group, R ₃ represents an alkyl group, and R ₄ and R ₅ each independently represent an alkyl group, aryl A group or an acyl group, or R ₄ and R ₅ are combined to form a ring, in which case R ₄ and R ₅ represent alkylene. ]