JP2014055263A - Nonaqueous ink composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide print ink excellent in storage stability and safety/hygiene, and excellent in discharge stability without adhesion to a nozzle.SOLUTION: A nonaqueous ink composition contains at least a pigment, a resin, and a solvent. The solvent comprises a solvent represented by the specified general formula (1) and an alkylene glycol alkyl ether acetate with a weight ratio in the range from 11:89 to 1:99. The resin is at least one of a vinyl chloride-vinyl acetate copolymer and an acrylic resin.

Description

  The present invention relates to a non-aqueous inkjet ink. In particular, the present invention relates to a printing ink, particularly an inkjet ink, which is excellent in storage stability and safety and hygiene as compared with conventional non-aqueous inkjet inks and excellent in ejection stability without adhering to a nozzle.

  Conventionally, gravure printing for soft packaging materials, flexographic printing for sanitary, silk screen printing for metal plates, inkjet printing for indoor and outdoor advertising, etc. are generally known as printing methods for non-absorbent substrates. However, ink compositions used in these printing methods generally use solvents such as toluene, ethyl acetate, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, etc., which are classified as organic solvents of the second type. For example, it is difficult to handle such as the installation of a local exhaust system or an obligation such as a periodic health check, and inks with higher safety and hygiene have been demanded. In particular, ink jets are used in offices such as general offices, unlike gravure printing, flexo printing, and silk screen printing, which are printed at a dedicated factory. Therefore, safety, toxicity, and odor must be considered.

  In order to improve safety, non-toluene inks that do not use toluene, which has a low environmental concentration setting value, and water-based inks based on alcohol have been developed for soft packaging gravure printing and sanitary flexographic printing.

  On the other hand, an ink using a polyalkylene glycol solvent or a hydrocarbon solvent that is not applicable to the second type organic solvent has also been developed in ink jet printing. (Patent Document 1) However, since the surface of the printing substrate cannot be dissolved with an ink comprising a polyalkylene glycol solvent or a hydrocarbon solvent, there are problems such as poor fixability and weather resistance.

  Therefore, recently, nitrogen-containing heterocyclic compounds such as 2-pyrrolidone and N-methyl-2-pyrrolidone, which are not applicable to the second type organic solvent, as well as polyalkylene glycol solvents, or lactone compounds are used in combination as cosolvents. Thus, solvent-based inks having improved fixability and weather resistance have been developed. (Patent Literature 2, Patent Literature 3, Patent Literature 4, Patent Literature 5, Patent Literature 6). However, these inks have problems such as dissolution of pigments, corrosion of the printer head material, and strong odor due to their high solubility.

Japanese Patent No. 3590486 Japanese Patent Laid-Open No. 2005-60716 JP 2005-15672 A JP 2005-200469 A Japanese Patent No. 3692365 JP 2005-248006 A

  An object of the present invention is to provide a non-aqueous ink composition excellent in long-term storage stability, safety and hygiene, and ejection stability, and a non-aqueous inkjet ink.

The present invention is characterized in that an ink containing at least a pigment, a resin, and a solvent contains at least a solvent represented by the following general formula (1) and a solvent represented by the following general formula (2). The present invention relates to a non-aqueous ink composition.
General formula (1)

(Wherein R ¹ is an alkyl group having 1 to 10 carbon atoms, and R ² and R ³ are each independently a hydrogen atom or a hydrocarbon group which may have an ether bond having 1 to 6 carbon atoms. They may be different from each other and may be further bonded to each other to form a ring structure.)
General formula (2)
CH ₃ CO (OR ⁴ ) _m OR ⁵

(In the formula, R ⁴ represents an ethylene group, a propylene group or a butylene group, R ⁵ represents an alkyl group having 1 to 4 carbon atoms, and m represents an integer of 1 to 3).

  Furthermore, the present invention provides the non-aqueous ink, wherein the weight ratio of the solvent represented by the general formula (1) and the solvent represented by the general formula (2) is in the range of 11:89 to 1:99. Relates to the composition.

  Furthermore, the present invention relates to the above non-aqueous ink composition, wherein the resin contains at least one of a vinyl chloride / vinyl acetate copolymer or an acrylic resin.

  Furthermore, the present invention relates to the non-aqueous ink composition, wherein the resin has a weight average molecular weight of 60000 or less.

  Furthermore, this invention relates to the said non-aqueous ink composition characterized by being an inkjet ink.

  Furthermore, the present invention relates to the non-aqueous ink composition described above, which is an ink printed on a vinyl chloride base material.

  According to the present invention, a non-aqueous ink composition having excellent long-term storage stability by adding a solvent represented by the general formula (1) and a solvent represented by the general formula (2) to the ink composition, In particular, non-aqueous inkjet inks are provided.

  As the organic solvent of the present invention, β-alkoxypropionamides represented by the general formula (1) and alkylene glycol alkyl ether acetates represented by the general formula (2) are preferably used. The β-alkoxypropionamides are less soluble in pigments than solvents such as N-methyl-2-pyrrolidone, but have high solubility in vinyl chloride resin and the like. Thereby, while excellent printing stability is obtained, long-term storage stability of ink physical properties is also obtained. Moreover, alkylene glycol alkyl ether acetates are excellent in continuous printing stability from the viewpoints of boiling point and resin solubility, as compared with alkylene glycol alkyl ethers.

  Further, the weight ratio of the β-alkoxypropionamide represented by the general formula (1) and the alkylene glycol alkyl ether acetate represented by the general formula (2) in the ink composition is 1:99 to 11: 89 is preferable, but 4:96 to 11:89 is preferable, and 6:94 to 11:89 is more preferable. When the addition ratio of β-alkoxypropionamides is more than 11:89, a part of the printing machine or printer member is corroded, and when it is less than 1:99, the effect of the printing performance due to its solubility cannot be obtained. It is not preferable.

In the β-alkoxypropionamides represented by the general formula (1), R ¹ is an alkyl group having 1 to 10 carbon atoms, and R ² and R ³ each independently represent a hydrogen atom or an ether bond having 1 to 6 carbon atoms. These may be hydrocarbon groups which may be the same or different from each other, and may be further bonded to each other to form a ring structure. R ¹ preferably has 1 to 4 carbon atoms, more preferably 1 to 2 from the viewpoint of the temporal stability of the ink.

Specific examples of the alkylene glycol alkyl ether acetates represented by the general formula (2) include ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol monobutyl ether acetate, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, Diethylene glycol monobutyl ether acetate, propylene glycol monomethyl ether acetate, dipropylene glycol monomethyl ether acetate, ethylene glycol monomethyl ether propionate, ethylene glycol monoethyl ether propionate, ethylene glycol monobutyl ether propionate, diethylene glycol monomethyl Ether ether propionate, diethylene glycol monoethyl ether propionate, diethylene glycol monobutyl ether propionate, propylene glycol monomethyl ether propionate, dipropylene glycol monomethyl ether propionate, ethylene glycol monomethyl ether butyrate, ethylene glycol monoethyl ether butyrate Rate, ethylene glycol monobutyl ether butyrate, diethylene glycol monomethyl ether butyrate, diethylene glycol monoethyl ether butyrate, diethylene glycol monobutyl ether butyrate, propylene glycol monomethyl ether butyrate, dipropylene glycol monomethyl ether butyrate, methoxybutyl acetate Glycol monoacetates, ethylene glycol diacetate, diethylene glycol diacetate, propylene glycol diacetate, dipropylene glycol diacetate, ethylene glycol acetate propionate, ethylene glycol acetate butyrate, ethylene glycol propionate butyrate, ethylene glycol dipro Pionate, ethylene glycol acetate dibutyrate, diethylene glycol acetate propionate, diethylene glycol acetate butyrate, diethylene glycol propionate butyrate, diethylene glycol dipropionate, diethylene glycol acetate dibutyrate, propylene glycol acetate propionate, propylene glycol acetate butyrate Tyrates, propylene glycol propionate butyrate, propylene glycol dipropionate, propylene glycol acetate dibutyrate, dipropylene glycol acetate propionate, dipropylene glycol acetate butyrate, dipropylene glycol propionate butyrate, dipropylene glycol dipro Examples thereof include glycol diacetates such as pionate and dipropylene glycol acetate dibutyrate.
Of these, ethylene glycol monobutyl ether acetate and dipropylene glycol monomethyl ether acetate are preferred.

  As the pigment used in the present invention, various pigments used in printing inks, paints and the like can be used. When these pigments are represented by color index, Pigment Black 7, Pigment Blue 15, 15: 1, 15: 3, 15: 4, 15: 6, 60, Pigment Green 7, 36, Pigment Red 9, 48, 49 , 52, 53, 57, 97, 122, 149, 168, 177, 178, 179, 206, 207, 209, 242, 254, 255, pigment violet 19, 23, 29, 30, 37, 40, 50, pigment Yellow 12, 13, 14, 17, 20, 24, 74, 83, 86, 93, 94, 95, 109, 110, 117, 120, 125, 128, 137, 138, 139, 147, 148, 150, 151 , 154, 155, 166, 168, 180, 185, 213, Pigment Orange 36, 43, 51, 5 , Such as 59,61,71,74, and the like. As for carbon black, any carbon black such as neutral, acidic and basic can be used. The pigment is desirably contained in the ink composition in an amount of 0.1 to 10% by weight.

  The resin used in the present invention has an effect of further improving the adhesion to a non-absorbent substrate. Usable resins include acrylic resin, styrene-acrylic resin, styrene-maleic resin, rosin resin, rosin ester resin, ethylene-vinyl acetate resin, petroleum resin, coumarone indene resin, terpene phenol Resin, phenol resin, urethane resin, melamine resin, urea resin, epoxy resin, cellulose resin, vinyl acetate resin, xylene resin, alkyd resin, aliphatic hydrocarbon resin, butyral resin, maleic acid resin, fumaric acid Examples thereof include resins. Specific examples of the resin include Superester 75 manufactured by Arakawa Chemical Co., Ltd., Ester Gum HP, Malkid 33, YS Polystar T80 manufactured by Yasuhara, Hirtts HRT200X manufactured by Mitsui Chemicals, John Kuryl 586 manufactured by Johnson Polymer, Dow Chemicals Yuker Solution Vinyl Resins VYHD, VYHH, VMCA, VROH, VYLF-X, Nissin Kagaku Vinyl Resin Solbin CL, CNL, C5R, TA5R, Wacker Vinyl Resins VINNOL E15 / 45, H14 / 36 , H40 / 43, E15 / 45M, and E15 / 40M. The resin is preferably contained in the ink composition in an amount of 0.1 to 10% by weight.

  Furthermore, at least one selected from vinyl acetate resin or acrylic resin as a binder resin for exhibiting functions such as scratch resistance, alcohol resistance, weather resistance, stretchability and substrate versatility of the ink coating film. It is preferable to contain. In addition, in order to stably discharge ink from the minute discharge ports of the ink jet printer head, a low viscosity ink is required, and a binder resin having a molecular weight Mw of 1000 or more and 60000 or less is preferable, and a molecular weight Mw of 2000 or more and 50000 or less. Binder resins are preferred.

  Furthermore, in this invention, it becomes possible to improve the dispersibility of a pigment and the storage stability of an ink composition by using a basic dispersing agent.

  Specific examples of the basic dispersion resin include Solspurs 11200, Solspurs 13240, Solspers 13650, Solspers 13940, Solspurs 16000, Solspers 17000, Solspers 18000, Solspers 20000, Solspers 24000SG, Solspers 24000GR, Solspers 38000, manufactured by Lubrizol. Solspurs 32000, Solspurs 32500, Solspurs 32550, Solspurs 32600, Solspers 33000, Solspers 34750, Solspers 35100, Solspers 35200, Solspers 37500, Solspers 38500, Solspers 39000, Solspers 56000, Solspers 71000, Sols 76500, Solspers X300, Solspers 9000, Solspers J200, DISPERBYK-108, DISPERBYK-109, DISPERBYK-112, DISPERBYK-116, DISPERBYK-130, DISPERBYK-161, DISPERBYK-162, DISPERBYSP -164, DISPERBYK-166, DISPERBYK-167, DISPERBYK-168, DISPERBYK-182, DISPERBYK-183, DISPERBYK-184, DISPERBYK-185, DISPERBYK-2000, DISPERBYK-2008, DISPERBYK-2009, SPERBYK-B, 2009 DISPERBYK-2050, DISPERBYK-2150, DISPERBYK-2155, DISPERBYK-2163, DISPERBYK-2164, BYK-9077, Ajinomoto Fine-Techno Co. AJISPER PB821, PB822, PB823, PB824, PB827, and the like. These dispersants can be used in accordance with the types of pigments and solvents. The dispersant is preferably contained in the ink in an amount of 0.1 to 10% by weight.

  The ink composition of the present invention can also use various additives such as a plasticizer, a surface conditioner, an ultraviolet light inhibitor, a light stabilizer, an antioxidant, and a hydrolysis inhibitor.

  Examples of the non-absorbable substrate whose effect can be confirmed in the present invention include a polyvinyl chloride resin (PVC) sheet, a polyolefin-based sheet, glass, metal, and the like, and a PVC sheet is particularly preferable.

[Example]

  EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not particularly limited to the examples. In the examples, “parts” and “%” represent “parts by weight” and “% by weight”.

[Production of Pigment Dispersion A]
Pigment dispersion A was prepared with the following composition. This pigment dispersion was prepared by putting a pigment and a dispersant in an organic solvent, stirring the mixture with a high speed mixer or the like until uniform, and then dispersing the obtained mill base with a horizontal sand mill for about 1 hour.

・ LIONOL BLUE FG-7400G (Toyocolor phthalocyanine pigment)
25.0 parts, Solsperse 32000 (basic pigment dispersant made by Lubrizol)
12.5 parts ethylene glycol monobutyl ether acetate
62.5 parts

[Example 1]
Using the pigment dispersion A, an ink composition of Example 1 was prepared with the following formulation. The β-alkoxypropionamides used are as shown in Table 1.

Pigment dispersion A 16.0 parts VINNOL E15 / 45 (vinyl acetate resin made by Wacker) 4.0 parts β-alkoxypropionamides (I) 1.0 part ethylene glycol monobutyl ether acetate 79.0 Part

[Examples 2-31 and Comparative Examples 1-5]
Ink compositions of Examples 2-31 and Comparative Examples 1-5 were prepared in the same manner as in Example 1, using the raw materials and blending ratios described in Tables 1, 2, and 3.

BGAc: ethylene glycol monobutyl ether acetate DPMA: dipropylene glycol monomethyl ether acetate DEDG: diethylene glycol diethyl ether MEDG: diethylene glycol methyl ethyl ether

The obtained ink compositions were comparatively evaluated by the following methods. The evaluation results are shown in Table 4. The evaluation method is shown below.

[Printing stability]
Under a 25 ° C environment, ColorPrinter 64S (manufactured by Seiko I Infotech Co., Ltd., large-format inkjet printer) continuously prints on the surface of untreated polyvinyl chloride resin sheet, and the frequency of occurrence of missing dots, flying bends or ink splashes Evaluated and the occurrence of dot missing, flying bent or ink splatter was less than 5 times in a 50 hour continuous test, ◎ 5 times or more but less than 10 times, ○ 10 times or more and less than 20 times Those that were present were evaluated as Δ, and those that were 20 times or more were evaluated as ×.

[mist]
Under an environment of 25 ° C., an arbitrary pattern is printed on a polyvinyl chloride resin sheet whose surface is not treated with ColorPainter 64S (manufactured by Seiko I Infotech, large format ink jet printer), and the mist amount is sensitively evaluated. Nothing was evaluated as ◎, slightly seen as ○, many seen as Δ, and very much as ×.

[Dechlorination]
In order to measure the amount of chlorine in the ink composition, 10 parts of the solvent pigment ink composition and 10 5 mmφ glass beads are charged into a sample bottle. After 90 parts of purified water was added while applying ultrasonic waves, the handshake was performed 60 times and allowed to stand for 20 minutes or longer, and then the lower aqueous phase was filtered using a membrane filter to obtain a sample for measuring the amount of chlorine. It was. The amount of chlorine in this sample was measured using a Dionex ion chromatograph DX-500.
As a determination method, the ink compositions obtained in Examples 1 to 31 and Comparative Examples 1 to 5 were evaluated as ◎, with an increase in chlorine amount of less than 20 ppm before and after acceleration at 70 ° C. for 6 weeks. Of 20 ppm or more and less than 30 ppm was evaluated as ◯, an increase of 30 ppm or more and less than 50 ppm was evaluated as Δ, and an increase of 50 ppm or more was evaluated as ×.

[Storage stability]
The viscosity of the ink compositions obtained in Examples 1 to 15 and Comparative Examples 1 to 11 was evaluated using an E-type viscometer (manufactured by Toki Sangyo) before and after aging at 70 ° C. for 8 weeks. , A viscosity change rate of less than 2%, ◎, a change rate of 2% to less than 5%, ◯, a change rate of 5% to less than 10%, and a change rate of 10% The above was evaluated as x.

As is apparent from Table 4, the ink compositions of Examples 1 to 31 containing the solvent of the general formula (1) and the solvent of the general formula (2) have printing stability, mist, dechlorination amount, and storage stability. All are excellent in sex. On the other hand, since Comparative Example 1 does not contain the solvent of the general formula (1), printing stability and mist are inferior. Since the comparative example 2 added the solvent which replaces the solvent of General formula (1), mist is inferior. Since the comparative example 3 replaced with the solvent of General formula (1) and added the solvent with strong solubility, it is inferior to the amount of dechlorination and storage stability. Since Comparative Examples 4 and 5 do not contain the solvent of the general formula (2), they are inferior in printing stability and storage stability.

Claims (6)

In an ink containing at least a pigment, a resin, and a solvent, the ink contains at least a solvent represented by the following general formula (1) and a solvent represented by the following general formula (2). Non-aqueous ink composition.
General formula (1)

(Wherein R ¹ is an alkyl group having 1 to 10 carbon atoms, and R ² and R ³ are each independently a hydrogen atom or a hydrocarbon group which may have an ether bond having 1 to 6 carbon atoms. They may be different from each other and may be further bonded to each other to form a ring structure.)

General formula (2)
CH ₃ CO (OR ⁴ ) _m OR ⁵

(In the formula, R ⁴ represents an ethylene group, a propylene group or a butylene group, R ⁵ represents an alkyl group having 1 to 4 carbon atoms, and m represents an integer of 1 to 3).
  The non-aqueous ink according to claim 1, wherein the weight ratio of the solvent represented by the general formula (1) and the solvent represented by the general formula (2) is in the range of 1:99 to 11:89. Composition.   The non-aqueous ink composition according to claim 1 or 2, wherein the resin contains at least one kind of a vinyl chloride / vinyl acetate copolymer or an acrylic resin.   The non-aqueous ink composition according to claim 1, wherein the resin has a weight average molecular weight of 60000 or less.   A non-aqueous ink composition, wherein the ink composition according to claim 1 is an inkjet ink. A non-aqueous ink composition, wherein the ink composition according to any one of claims 1 to 5 is an ink printed on a vinyl chloride base material.