JPH05320558A - Oil-based black ink - Google Patents

Abstract

PURPOSE:To obtain the subject product storable for a long period without causing the lowering of the solubility of nigrosin, having excellent ink-delivery performance and keeping acceptable writing performance even after a long-term storage by compounding a specific solubilizing agent to a composition composed of nigrosin, an aliphatic alcohol solvent and a resin. CONSTITUTION:The objective product contains (A) nigrosin as a coloring material, (B) lactic acid and/or its ester as a solubilizing agent for the component A, (C) an aliphatic alcohol (preferably >=4C alcohol such as methanol) as a solvent and (D) a resin soluble in the component C for controlling the viscosity and improve the fixability (e.g. phenolic resin). The amounts of the components A, B, C and D are preferably 7-15wt.%, 3-20wt.%, 40-90wt.% and 1-20wt.% based on the total ink, respectively.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an oily black ink which is excellent in stability over time and has good ink discharge when used for writing instruments, recorders and jet printers.

[0002]

2. Description of the Related Art Conventional oil-based black inks include nigrosine as a coloring agent, fatty acids such as oleic acid as a solubilizing agent, and aromatic hydrocarbons such as xylene and toluene as a solubilizing agent because of their high concentration and low price. Are known to use. However, since aromatic hydrocarbons have problems such as high odor and toxicity, in recent years, many proposals have been made to use an aliphatic alcohol having low odor and toxicity as a solvent for oil-based ink.

[0003]

However, the oil-based ink using an aliphatic alcohol as a solvent has a poor solubility of nigrosine, and therefore, when used in a writing instrument, a recorder, a jet printer, etc. ,
After storage for a long period of time, there were many problems such as scratches and the inability to write.

[0004]

The present invention comprises at least nigrosine, lactic acid and / or its ester, an aliphatic alcohol, and a resin soluble in the aliphatic alcohol, which is an oily black ink. Is the gist.

The details will be described below. Nigrosine is used as a coloring material, and its addition amount is preferably 7 to 15% by weight based on the total amount of the ink. If the added amount is less than 7% by weight, the concentration in the form of handwriting tends to decrease, and if the added amount is more than 15% by weight, the viscosity becomes high and the ink discharge decreases for writing instruments, recorders and jet printers. Tend to do.

Lactic acid and / or its ester is used as a solubilizing agent for nigrosine in aliphatic alcohol. Specific examples of the lactate ester include methyl lactate, ethyl lactate, propyl lactate, normal butyl lactate, isobutyl lactate, normal amyl lactate and isoamyl lactate. The amount added is 3 to 20 with respect to the total amount of ink.
Addition by weight% is preferable, and if it is less than 3% by weight, the effect tends to be small, and if it is more than 20% by weight, the viscosity tends to be high and the handwriting dryness tends to be poor.

Aliphatic alcohols are used as solvents. Specific examples include methyl alcohol, ethyl alcohol, normal propyl alcohol, isopropyl alcohol, normal butyl alcohol, isobutyl alcohol, tertiary butyl alcohol and the like. These may be used alone or as a mixture of two or more, and it is preferable to add 40 to 90% by weight to the total amount of the ink. Furthermore, from the viewpoint of handwriting dryness, it is more preferable to use an aliphatic alcohol having 4 or less carbon atoms.

The resin soluble in the aliphatic alcohol is used for adjusting the viscosity and improving the fixing property of the coloring material. Examples thereof include phenol resin, ketone resin, rosin resin, butyral resin, polyamide resin and the like. As a specific example, as a phenol resin, Tamanol 100S, 5
10 (above, Arakawa Chemical Industry Co., Ltd.), Hitanol 15
01, 2501 (above, manufactured by Hitachi Chemical Co., Ltd.) and the like, as a ketone resin, ketone resin K-90 (manufactured by Arakawa Chemical Industry Co., Ltd.), Halon 110H (honshu chemical Co., Ltd.)
Manufactured by Rika Hercules Co., Ltd.
Manufactured by China), gum rosin WW (manufactured by China), etc. are used as butyral resins as Denka butyral # 2000-L and # 30.
00-1, ibid # 3000-2, ibid # 3000-4, ibid #
3000-K (all manufactured by Denki Kagaku Kogyo Co., Ltd.)
As a polyamide resin, AQ-nylon A-90, A
-70, A-50, P-70, K-80, K-
14 (above, manufactured by Toray Co., Ltd.), Newmide 825, 840 (above, manufactured by Casey Co., Ltd.), Resin F3
0, same MF-30, same EF-30T, same M-20, same T
K5036 (above, N-methoxymethylated nylon, Teikoku Chemical Industry Co., Ltd.), Versamide 744, 756,
711 (above, manufactured by Henkel Hakusui Co., Ltd.), Thomaid # 90, # 92 (above, manufactured by Fuji Kasei Kogyo Co., Ltd.), Sanmide 611DK-1, 615A (above manufactured by Sanwa Chemical Industry Co., Ltd.) ) And the like. These may be used alone or as a mixture of two or more, and it is preferable to add 1 to 20% by weight to the total amount of the ink.

Further, in addition to the above components, if necessary, various antiseptics, antifungal agents, wetting agents, drying inhibitors, viscosity modifiers, freeze stabilizers, antifoaming agents, surfactants, etc. It is also possible to appropriately select and use the additive of.

The oily black ink is obtained by stirring and mixing the above-mentioned essential components with a conventionally known stirrer and dissolving them uniformly.

[0011]

Since the oil-based black ink according to the present invention uses lactic acid and / or its ester as a solubilizing agent for nigrosine, nigrosine is well dissolved in a solvent, and this dissolved state should be stored for a long period of time. It is presumed that the ink is ejected well because clogging is less likely to occur at the pen tip of the writing instrument or the nozzle of the printer.

[0012]

EXAMPLES The present invention will be described in more detail below with reference to examples. In the examples and comparative examples, the term "part" simply means "part by weight".

Example 1 Nigrosine base EX (Nigrosine, manufactured by Orient Chemical Industry Co., Ltd.) 12 parts Ethyl alcohol 49 parts Isopropyl alcohol 20 parts Ethyl lactate 14 parts Halon 110H 5 parts The above components are stirred for 4 hours. The oily black ink was obtained by stirring.

Example 2 Oil Black S (Nigrosine, manufactured by Chuo Gosei Co., Ltd.) 10 parts Ethyl alcohol 45 parts Methyl alcohol 15 parts Methyl lactate 20 parts Tamanol 100S 10 parts The above components are the same as in Example 1. Then, an oily black ink was obtained.

Example 3 Nigrosine base EX 7 parts Normal propyl alcohol 71 parts Lactic acid 10 parts Gum rosin WW 12 parts The same components as in Example 1 were used to obtain an oily black ink.

Example 4 Oil Black FS Special (Nigrosine, manufactured by Chuo Gosei Co., Ltd.) 13 parts Isopropyl alcohol 60 parts Benzyl alcohol (viscosity modifier) 14 parts Normal butyl lactate 5 parts Denkabutyral # 3000- K 8 parts The same components were used as in Example 1 to obtain an oily black ink.

Example 5 Nigrosine base EX 10 parts Ethyl alcohol 70 parts Isoamyl lactate 10 parts Halon 110H 8 parts Tamanol 100S 2 parts The same components as in Example 1 were used to obtain an oily black ink.

Example 6 Oil Black FS Special 8 parts Normal propyl alcohol 58 parts Propylene glycol monomethyl ether (drying inhibitor) 20 parts Lactic acid 4 parts Newmide 825 10 parts The above components were the same as in Example 1. Then, an oily black ink was obtained.

Comparative Example 1 In Example 1, ethyl lactate was removed and 5 oleic acid was added.
Parts and 9 parts of ethanol were added to obtain an oily black ink in the same manner as in Example 1.

Comparative Example 2 An oil-based black ink was obtained in the same manner as in Example 3, except that lactic acid was removed from Example 3 and capric acid was added in that amount.

The oily black inks obtained in Examples 1 to 6 and Comparative Examples 1 and 2 were filled in a pen tip having a fiber core and a writing instrument (Mark Pentel MS50, manufactured by Pentel Co., Ltd.) using batting. Then, an ink discharge test, a writing test after a lapse of time, and an ink reactivity test were performed. The results are shown in Table 1.

[0022]

[Table 1]

Ink Discharge Test Using a spiral writing tester, the ink discharge amount was measured on JIS P 3201 Writing Paper A at a writing speed of 10 cm / sec, a writing load of 100 g, and a writing angle of 60 ° for 100 m. (Unit: g)

Writing test after aging After the writing implement filled with the above oily black ink was stored in a constant temperature chamber at 50 ° C. for one month, JIS P 3201 Writing paper A was used.
I wrote the spiral writing by hand. Evaluation ◯: Vivid and good handwriting was obtained Δ: Some blur was observed ×: Writing was not possible

Ink Reactivity Test After the above oily black ink was stored in a constant temperature chamber at 50 ° C. for 3 months, filter paper No. 5c (manufactured by Advantech Toyo Corp.) was instilled and the state was observed. Evaluation ◯: No residue X: Residue

[0026]

As described above in detail, the oil-based black ink according to the present invention is excellent in ink dischargeability, can be written well after a lapse of time, and has a solubility of nigrosine even when stored for a long period of time. It has the characteristic of not decreasing.

Claims (1)

[Claims] 1. An oil-based black ink comprising at least nigrosine, lactic acid and / or its ester, an aliphatic alcohol, and a resin soluble in the aliphatic alcohol.