JPH0971745A - Oil-based black ink - Google Patents

Abstract

(57) Abstract: To increase the density of handwriting and improve the fixing property of the handwriting on the non-absorption surface in an oily black ink using a lower aliphatic alcohol having 4 or less carbon atoms as a solvent. SOLUTION: 2.0 to 20.0% by weight of a black dye obtained by forming a salt of a triarylmethane-based purple basic dye and an azo-based yellow acidic dye, and an aliphatic alcohol having 40 or less carbon atoms. An oil-based black ink containing at least 0 to 90.0% and a urethane-modified ketone-formaldehyde resin of 1.0 to 20.0%.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention is preferably used for writing instruments, recorders and jet printers, and forms a coating film having a high density on the non-absorptive surface and good fixability, and stability over time. It relates to an excellent oily black ink.

[0002]

2. Description of the Related Art Conventionally, oil-based black inks used for quick-drying marking pens and the like mainly contain an oil-soluble black dye, an oil-soluble resin and a solvent. Compared to water-based inks containing water-based dyes and water as the main components, oil-based black inks are capable of good writing on not only the ink-absorbing surface of paper, cloth, etc., but also the non-ink-absorbing surface of glass, metal, plastic, etc. Therefore, it is often used. As the oil-soluble black dye of the oil-based black ink, a nigrosine dye, a 1: 2 type metal complex salt dye, a salt-forming oil-soluble dye, etc. are used, and the solvent is an aromatic hydrocarbon such as toluene or xylene, or ethylene glycol. Glycol ethers such as monomethyl ale and ethylene glycol monoethyl ether are used. However, the above-mentioned solvent has a problem of safety to human body such as high odor and toxicity, and in recent years, it has been proposed to use aliphatic alcohol having a carbon number of 4 or less, which has low odor and toxicity, as a solvent for oil-based ink. There is.

[0003]

However, it is very difficult to increase the density of handwriting in an oily black ink using a lower aliphatic alcohol having a carbon number of 4 or less as a solvent. To solve this problem, it is possible to add a large amount of dye. However, Nigrosine dye and 1: 2
When a large amount of type metal complex salt dye is added, the ink becomes highly viscous, and considering the decrease in ink discharge from the pen tip when used in writing instruments, etc., the addition amount is limited, so to obtain a sufficient concentration. Has not arrived. Further, the nigrosine dye has poor solubility in lower aliphatic alcohols, and the dye is likely to precipitate in the ink due to evaporation of the solvent in a long-term state. Therefore, clogging of the capillary of the pen tip occurs,
There is a problem that blurring of handwriting easily occurs. However, when a salt-forming oil-soluble dye, which has relatively good solubility in lower aliphatic alcohols, is used, it is possible to prevent the ink from becoming highly viscous due to the addition of the dye, and to prevent the dye from precipitating due to solvent evaporation. . However, salt-forming oil-soluble dyes lose their salt-forming property when stored for a long period of time.
There is a fundamental problem that secondary aggregation occurs between the dyes and the resin, and precipitates are formed and accumulated. The generation of deposits causes problems such as a decrease in ink concentration and a decrease in productivity in the manufacturing process (for example, clogging of an ink filling machine nozzle during ink filling).

Further, the oily black ink using a lower aliphatic alcohol having a carbon number of 4 or less as a solvent is said to have poor fixability on the non-absorption surface of the handwriting such as handwriting being easily erased by contact with an object or friction. There are also problems. To solve this problem, it is possible to add a large amount of resin in order to improve the effect of fixability, but if a large amount of resin is added, the ink will become highly viscous, and the pen when used in writing instruments, etc. Considering the decrease in ink discharge from the beginning, the amount of addition is limited, so that sufficient fixability has not been obtained.
In addition, conventional resins have poor solubility in aliphatic alcohols, and solid-state components in the ink are likely to precipitate due to evaporation of the solvent in a long-term state. Therefore, there is a problem that clogging of the capillary of the pen tip occurs, and blurring of handwriting easily occurs.

[0005]

Means for Solving the Problems The present invention comprises a black dye obtained by salting a triarylmethane type purple basic dye and an azo yellow acidic dye, an aliphatic alcohol having 4 or less carbon atoms, An essential feature is an oil-based black ink containing at least a urethane modified ketone formaldehyde resin.

The details will be described below. A black dye obtained by forming a salt of a triarylmethane-based purple basic dye and an azo-based yellow acidic dye is used as a colorant, and is soluble in an aliphatic alcohol having 4 or less carbon atoms. Is good. Examples of the triarylmethane-based purple basic dye include C.I. I. Basic Violet 1, C.I. I. Basic Violet 3 and the like can be mentioned. As the azo yellow acidic dye, C.I. I. Acid Yellow 1
1, C.I. I. Acid Yellow 17, C.I. I. Acid Yellow 23, C.I. I. Acid Yellow 25, C.I.
I. Acid Yellow 29, C.I. I. Acid Yellow 36, C.I. I. Acid Yellow 42 and the like. A salt-forming dye can be easily produced using these dyes by a conventionally known method. For example, an aqueous solution of a triarylmethane-based purple basic dye and an aqueous solution of an azo-yellow acidic dye are mixed and stirred at a temperature of room temperature to 100 ° C. Then, the water-insoluble reaction product is filtered, washed with water and dried to obtain a black dye. The amount used is preferably 2.0 to 20.0% by weight based on the total amount of the ink. If the added amount is less than 2.0% by weight, the concentration in the form of handwriting tends to decrease, and if the added amount is more than 20.0% by weight, the viscosity becomes high and it is used for writing instruments, recorders and jet printers. When used, ink ejection tends to decrease.

[0007] Aliphatic alcohols having 4 or less carbon atoms are used as solvents. Specifically, methyl alcohol, ethyl alcohol, normal propyl alcohol,
Isopropyl alcohol, normal butyl alcohol,
Examples thereof include isobutyl alcohol and tertiary butyl alcohol. These can be used alone or as a mixture of two or more, and the amount used is 40.0-9 with respect to the total amount of ink.
It is preferable to add 0.0% by weight.

The skeleton of the present invention, the urethane-modified ketone formaldehyde resin, is used for improving the fixability of the coating film on the non-absorption surface and for adjusting the ink viscosity. In addition, since this resin has a higher softening point than other oil-soluble resins, the drying property of the coating film is good even when an ink containing a large amount of resin is used to enhance the fixing property. have. The amount used is preferably 1.0 to 20.0% by weight based on the total amount of the ink. Furthermore, urethane-modified ketone formaldehyde resin has excellent compatibility with other oil-soluble resins such as melamine resin, urea resin, alkyd resin, and polyester resin,
They can be used together depending on the situation.

If necessary, in addition to the above essential components, a colorant for complementary colors, a viscosity adjusting agent for inks, an anticorrosive agent for preventing metal corrosion, and a plasticizer for imparting flexibility to an ink coating film to enhance adhesion. Etc. can be appropriately selected and used. Examples of the complementary colorant include alcohol-soluble yellow dyes and red dyes. Examples of the viscosity modifier of the ink include high boiling point alcohol solvents such as benzyl alcohol, glycol ether solvents such as ethylene glycol monophenyl ether and propylene glycol lower alkyl ether, and ester solvents such as ethyl acetate and ethyl lactate. Examples of the metal anticorrosion agent include benzotriazole. As the plasticizer, phthalic acid ester, sebacic acid ester, phosphoric acid ester, adipic acid ester, maleic acid ester,
Examples thereof include stearic acid ester and trimetic acid ester.

Further, various surfactants can be used as a solubilizing agent for a dye, an anti-drying agent for a pen tip, an agent for improving applicability of ink, and an agent for improving ink ejection. Specifically, alkyl sulfates, N-acyl amino acids and salts thereof,
Anionic surfactants such as polyoxyethylene alkyl ether acetate and polyoxyethylene alkyl ether phosphate, nonionic surfactants such as polyoxyethylene alkyl ether, sorbitan fatty acid esters and decaglycerin fatty acid ester, perfluoroalkyl Examples thereof include fluorinated surfactants such as sulfonates and polyoxyethylene perfluoroether, and silicone-based surfactants such as polyether modified silicone and alcohol modified silicone.

The oily black ink of the present invention can be obtained by stirring and mixing the above essential components with a conventionally known stirrer and dissolving them uniformly.

[0012]

[Function] Deposition of a dye in an oil-based black ink using a salt-forming oil-soluble dye occurs due to some influence of salt formation of a part of dye molecules in a solution and secondary aggregation with dyes or a resin. It is a thing. However, since this urethane-modified ketone-formaldehyde resin maintains a stable dissolved state in a solvent, it is possible to suppress the precipitation of the dye. Therefore, it is presumed that the ink is stable even after being stored for a long period of time, and excellent handwriting can be obtained even when the ink is filled and used as a writing instrument. Further, since the urethane-modified ketone formaldehyde resin has a urethane structure in its molecule, it exhibits excellent solubility in an aliphatic alcohol having 4 or less carbon atoms. When an ink containing this resin is applied to the non-absorption surface, the resin forms a network structure by forming cross-linking between urethane molecular chains as the solvent evaporates. As a result, the base film of the ketone-formaldehyde resin is strengthened and is firmly bonded to the writing surface. Furthermore, since the dye molecules are evenly dispersed in the interstices of the mesh, the density of the coating film looks high.

[0013]

The present invention will be described below in more detail with reference to examples. Example 1 C.I. I. Basic Violet 3 and C.I. I. Salt formation with Acid Yellow 36 Dye 14.0 parts by weight Ethyl alcohol 60.0 parts by weight Urethane modified ketone formaldehyde resin 3.0 parts by weight Ethyl acetate (viscosity modifier) 3.0 parts by weight Propylene glycol monomethyl ether (viscosity adjuster Agent) 17.0 parts by weight Spiron Yellow C-2GH (complementary color, manufactured by Hodogaya Chemical Co., Ltd.) 3.0 parts by weight The above components were stirred for 4 hours with a stirrer to obtain an oily black ink.

Example 2 C. I. Basic Violet 3 and C.I. I. Salt formation with Acid Yellow 36 Dye 18.0 parts by weight Ethyl alcohol 37.0 parts by weight Methyl alcohol 30.0 parts by weight Urethane modified ketone formaldehyde resin 5.0 parts by weight Ethyl acetate (previously mentioned) 5.0 parts by weight Benzyl alcohol (viscosity modifier) 5.0 parts by weight The same components were used as in Example 1 to obtain an oily black ink.

Example 3 C. I. Basic Violet 3 and C.I. I. Salt formation with Acid Yellow 36 Dye 10.0 parts by weight Normal propyl alcohol 50.0 parts by weight Ethyl alcohol 18.0 parts by weight Urethane modified ketone formaldehyde resin 10.0 parts by weight Ethyl acetate (above) 10.0 parts by weight Parts Oil Yellow CH (Complementary Coloring Agent, manufactured by Chuo Gosei Kagaku Co., Ltd.) 2.0 parts by weight The same components were used as in Example 1 to obtain an oily black ink.

Example 4 C. I. Basic Violet 1 and C.I. I. Salt formation with Acid Yellow 36 Dye 12.0 parts by weight Isopropyl alcohol 62.0 parts by weight Urethane modified ketone formaldehyde resin 1.5 parts by weight Ethyl acetate (described above) 1.5 parts by weight Propylene glycol monomethyl ether (described above) 20 0.0 parts by weight Tomide # 92 (polyamide resin, manufactured by Fuji Kasei Kogyo Co., Ltd.) 3.0 parts by weight The above components were treated in the same manner as in Example 1 to obtain an oily black ink.

Example 5 C. I. Basic Violet 1 and C.I. I. Salt formation with Acid Yellow 36 Dye 10.0 parts by weight Ethyl alcohol 64.0 parts by weight Normal butyl alcohol 15.0 parts by weight Urethane modified ketone formaldehyde resin 4.5 parts by weight Ethyl acetate (above) 4.5 parts by weight Spin 2.0 parts by weight of Ron Yellow C-2GH (described above) The above components were treated in the same manner as in Example 1 to obtain an oily black ink.

Example 6 C. I. Basic Violet 3 and C.I. I. Salt formation with Acid Yellow 17 Dye 5.0 parts by weight Ethyl alcohol 60.0 parts by weight Normal propyl alcohol 16.0 parts by weight Urethane modified ketone formaldehyde resin 18.0 parts by weight Oil yellow CH (previously described) 1.0 Parts by weight The above components were treated in the same manner as in Example 1 to obtain an oily black ink.

Example 7 C. I. Basic Violet 3 and C.I. I. Salt formation with Acid Yellow 23 Dye 9.0 parts by weight Isopropyl alcohol 50.0 parts by weight Methyl alcohol 27.0 parts by weight Urethane modified ketone formaldehyde resin 12.0 parts by weight Spylon Yellow C-2GH (previously described) 2.0 parts by weight The above components were treated in the same manner as in Example 1 to obtain an oily black ink.

Example 8 C. I. Basic Violet 3 and C.I. I. Salt formation with Acid Yellow 42 Dye 13.0 parts by weight Ethyl alcohol 76.0 parts by weight Urethane modified ketone formaldehyde resin 8.0 parts by weight Benzyl alcohol (previously described) 3.0 parts by weight The above components are the same as in Example 1. Then, an oily black ink was obtained.

Example 9 C. I. Basic Violet 1 and C.I. I. Salt formation with Acid Yellow 23 Dye 10.0 parts by weight Normal propyl alcohol 60.0 parts by weight Normal butyl alcohol 8.0 parts by weight Urethane modified ketone formaldehyde resin 7.0 parts by weight Propylene glycol monomethyl ether (previously described) 15. 0 parts by weight The above components were treated in the same manner as in Example 1 to obtain an oily black ink.

Comparative Example 1 The urethane-modified ketone-formaldehyde resin in Example 1 was removed, and the amount of Halon 110H (ketone resin,
An oily black ink was obtained in the same manner as in Example 1 except that Honshu Kagaku Co., Ltd. was added.

Comparative Example 2 The procedure of Example 1 was repeated except that the urethane-modified ketone formaldehyde resin was removed, and Tamanol 100S (phenolic resin, manufactured by Arakawa Chemical Industry Co., Ltd.) was added in that amount. A black ink was obtained.

The oil-based black inks obtained in Examples 1 to 9 and Comparative Examples 1 and 2 were subjected to an ink low temperature aging test. In addition, the oil-based black inks obtained in Examples 1 to 9 and Comparative Examples 1 and 2 were applied to a pen tip having a fiber core and a writing instrument using a batting (Pentel cloth brush pen super [fine character] NM10, manufactured by Pentel Co., Ltd.). After filling, a handwriting density test and a handwriting peeling test were performed. The results are shown in Table 1.

[0025]

[Table 1]

Ink low temperature aging test The above oily black ink was sealed in a bottle with a lid and kept at -20 ° C.
After storing in a thermostatic chamber for 1 month, the ink was filtered with a filter paper (manufactured by Advantech Toyo Co., Ltd.) to confirm the state of the residue on the filter paper. Evaluation ◯: No precipitate Δ: Little precipitate x: Precipitate

Handwriting density test Clear sheet [thin mouth] (manufactured by Ricoh Educational Equipment Co., Ltd.)
In addition, using a writing instrument filled with the above oily black ink, the ink was applied uniformly once in each of the vertical and horizontal directions and dried,
The density was measured with an SM color computer (MODEL, SM-4, manufactured by Suga Test Instruments Co., Ltd.). The determination method is evaluation using the luminous reflectance Y value, and the smaller the numerical value, the higher the density. (unit:%)

Handwriting Peeling Test The above-mentioned test film used in the handwriting density test is overlaid with quality paper, and a weight having a bottom diameter of 50 mm and a mass of 500 g is placed.
The peeled state of the handwriting which was moved left and right 10 times was measured using an SM color computer. The judgment method is evaluated by using the color difference ΔE of the handwriting density before and after the test, and the smaller the value, the less the peeling of the handwriting.

[0029]

As described above in detail, the oil-based black ink according to the present invention does not deposit even in a low temperature aging test in which a dye or resin is likely to deposit, and thus does not cause blurring of handwriting and is non-absorbing. In this way, it is possible to obtain handwriting with a high density and a high fixing property.

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Claims (1)

[Claims] 1. A black dye obtained by forming a salt of a triarylmethane-based purple basic dye and an azo-based yellow acidic dye, an aliphatic alcohol having 4 or less carbon atoms, and a urethane-modified ketone-formaldehyde resin. Oily black ink characterized by containing.