JPH02251578A - Oil-based ink capable of absorbing near-infrared ray - Google Patents

Abstract

PURPOSE:To obtain an oil-based ink containing an organic solvent, wax and specific nickel complex, capable of absorbing light at near-infrared region and having high solubility to organic solvents and waxes and excellent fastness. CONSTITUTION:The objective ink containing (A) an organic solvent (e.g. toluene or methylcellosolve acetate) and/or wax (preferably having 80 to 120 deg.C softening point) and (B) a nickel complex (e.g. expressed by formula II) or generally expressed by formula I [R<1> and R<2> are (substituted) lower alkyl; X is H, halogen, lower alkyl, lower alkoxy or acylamino; Y is H, halogen or lower alkyl; (m) is 2 or 3; Z is halogen ion, acetic acid ion, ClO, BF, PF, or tetraphenylboran ion], preferably of 2-10wt.%.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an oil-based ink that absorbs near-infrared rays and is suitable for writing instruments, stamps, printing, recorders, thermal transfer printers, and the like.

[Conventional technology]

Recently, there has been an increase in rationalization by strengthening logistics management in production and sales. One of the technologies supporting this is the widespread use of optical character recognition (OCR) devices or barcode recognition devices.

Coupled with the recent development of semiconductor lasers, light in the vicinity of 7tO to 30nm is used for these readings.

Conventionally, carbon black, nigrosine dyes, chromium- or cobalt-containing dyes, etc. have been used for their light-absorbing properties, but they have insufficient solubility, mutagenicity, and health and safety issues. There were problems and it was not necessarily satisfactory.

Further, as other infrared absorbing coloring materials, for example, organometallic complexes such as benzenedithiol-based metal complexes and benzenediamine-based metal complexes have low oil solubility, and therefore cannot be added to oil-based inks.

[Problem that the invention seeks to solve]

The present invention aims to provide an oil-based ink that absorbs light in the near-infrared region, has high solubility in organic solvents or waxes, and has excellent fastness.

[Failure to solve the problem]

The present inventor has conducted various studies to solve the above problems, and as a result, the following general formula CI) (wherein, R1 and R2 represent a substituted or unsubstituted lower alkyl group, and X is a hydrogen atom or a halogen atom) , represents a lower alkyl group, a lower alkoxy group, or an acylamino group,
Y represents a hydrogen atom, a halogen atom, or a lower alkyl group, m represents co or 3, and Z can be a halogen ion, an acetate ion, ClO4-BF4PF6- or a tetraphenyl group).

Next, the present invention will be explained in more detail.

R1%R of the nickel complex represented by the above general formula [I]
Examples of the lower alkyl group in 2 include an alkyl group having a carbon number/-3, such as a methyl group, an ethyl group, a propyl group, and a butyl group, and examples of the substituent in the substituted lower alkyl group include an acetyloxy group and a propionyloxy group. Acyloxy groups such as; alkoxy groups such as methoxy, ethoxy, and methoxyethoxy groups; alkoxycarbonyl groups such as methoxycarbonyl and ethoxycarbonyl groups; hydroxyl groups; halogen atoms such as chlorine and bromine; can give. In X, examples of the halogen atom include a chlorine atom and a bromine atom, examples of the lower alkyl group include a methyl group and an ethyl group, examples of the lower alkoxy group include a methoxy group and an ethoxy group, and examples of the acylamino group include acetylamino. group, glopionylamino group, and benzoylamino group.

The halogen atom and lower alkyl group in Y are the same as those in XK, and examples of the halogen ion in Z include chlorine anion and bromine anion.

Specific examples of the compound used as the near-infrared absorber represented by the general formula [I] of the present invention are summarized below.

The nickel complex represented by the general formula CII is bo
It has absorption in the wavelength band of o to qo o nm, and has a molecular extinction coefficient of 105 to 2,105.

These compounds used in the present invention include, for example, Kubo,
Chem, Let t, by Sasaki, Yoshihito et al.

/91ri,/;43. It can be manufactured according to the description in .

Further, the content of the nickel complex in the ink is o, 5 to 20% by weight, preferably 2% by weight, based on the total weight of the oil-based ink.
~70% by weight.

The oil-based ink of the present invention may contain a near-infrared light absorber made of a compound represented by the general formula CI), and another oil-soluble resin whose essential components are an organic solvent and/or wax.

Examples of organic solvents used in the oil-based ink of the present invention include aromatic solvents such as toluene and xylene, cellosolve acetate solvents such as methyl cellosolve acetate and ethyl cellosolve acetate, ethylene glycol monomethyl ether, diethylene glycol monobutyl ether, and dipropylene glycol dimethyl ether. Examples include polyhydric alcohol ether solvents such as, butanol, conitylhexanol, and alcohol solvents such as benzyl alcohol.

The oil-soluble resin used in the oil-based ink of the present invention includes:
Examples include rosin resin, rosin-phenolic resin, rosin-maleic acid resin, alkyd resin, petroleum-based hydrocarbon resin, ketone resin, alkylphenol novolak resin, etc., and the amount used is 5 to 30% based on the total weight of the oil-based ink.
% by weight, preferably S-20% by weight.

The oil-based ink prepared from the above-mentioned organic solvent, oil-soluble resin, and the above-mentioned nickel complex (I) includes sainben,
Can be sharpened for stationery such as markers.

The wax used in the oil-based ink of the present invention has a melting point or softening point of ao-Izo°C, preferably 0 to 720°C.

If the melting point or softening point is lower than 1IO°C, it becomes sticky at room temperature, which is undesirable (on the other hand, if it is higher than 15θ°C, good printing quality may not be maintained depending on the method of use, which is undesirable.

Further, as the wax specifically used in the present invention, it is preferable to use a nitrogen-containing wax, and examples thereof include the following.

Colaurylimidacillin, Coundecyl imidazoline (Melting point = 77-73°C), l-cyanoethyl-Coundecyl imidazoline (Melting point: S/~5.2°C), l
-Imidazoles such as -dodecyl-comethyl-3-benzyl-imidazolinium chloride (melting point: A/-47°C); lauric acid amide (melting point: 2g6°C), stearic acid amide (melting point: ioi°C), N- Fatty acid amides such as hydroxymethyl-stearamide (melting point: ///℃), N-lauryl-lauric acid amide (melting point: qa℃); butylstearylurea (melting point: 9t℃), dilauryl urea (melting point: / /!℃); higher alkylamines such as laurylamine (melting point: !IO℃), oleylamine, lauryl aminopropylamine, octadecylamine; polyethylene octadecylamine, α
, polyoxyethylene amines such as ω-bis-aminopropyl-polyethylene glycol ether; reaction products of higher alcohols such as lauryl alcohol and undecyl alcohol with tolylene diisocyanate, methylene diisocyanate, and the like.

Further, wax paraffins such as candelilla wax, carnauba wax, beeswax, montan wax, ceresin wax, etc. may be used in combination with the above wax, if necessary.

Further, thermoplastic resins such as polyamides and polymaleimides may be used in combination with the waxes mentioned above.

These waxes and thermoplastic resins used in combination as necessary may be used alone, but by mixing two or more types, the melting point or softening point can be increased to 0°C to 0°C, preferably around 0°C. It is preferable to adjust the temperature to 0 to 0°C.

Furthermore, it is also possible to add a plasticizer, antioxidant, and ultraviolet absorbent as necessary.

In addition, in order to mix the nickel complex of the above-mentioned maximum CI) with waxes and thermoplastic resin, melt mixing or
It is possible to mix it into a solution with alcohol or the like.

The oil-based ink prepared using waxes in this way is coated onto a film of polyester, polyimide, polycarbonate, nylon, etc. having a thickness of 3 to 30 μm, preferably 3 to 20 μm, and a thickness of 2 to 70 μm, preferably 3 to 6 μm.
Hot melt coater comma coater for dry thickness
A sheet for transfer recording can be manufactured by coating with a gravure coater or the like or by impregnating a knitted fabric to form a coloring layer.

Thus, the oil-based ink obtained by the present invention itself strongly absorbs near-infrared rays, and the image portion drawn using it also strongly absorbs near-infrared rays.

Therefore, by using the oil-based ink of the present invention for writing instruments, stamps, printing, thermal transfer printers, and recorders, it is possible to read with an optical reading device that uses near-infrared rays as the reading light.

The present invention will be explained below using examples. All parts shown in the examples are parts by weight.

Example/ Diamond Y 97 parts (fatty acid amide, trade name, manufactured by Nippon Kasei) (melting point Nizaru ℃) 3 parts of the above-mentioned Mako compound Total 70
0 parts of wax and Ni complex were melt-mixed at 50° C. with the above composition. This mixture was coated on a polyester film (thickness: 70 μm) using a true melt coater to form an ink layer of S μm to produce a heat-sensitive transfer recording sheet.

This sheet was used to print on electrophotographic paper using a thermal printer STgO (trade name, manufactured by Star Seimitsu ■).

It was confirmed using a U-3'100 Hitachi self-recording spectrophotometer (manufactured by Hitachi, Ltd.) that the printed portion sufficiently absorbed light in the 7tO to 30nm range.

(α-olefin-maleimide copolymer resin, manufactured by Mitsubishi Kasei Shihata) (Softening point near 0°C) Compound of rot 9 5 parts total 100
A thermoplastic resin and a Ni complex were melt-mixed at 100°C with the above composition.

This mixture was applied using a hot-melt coater onto a film made by vapor depositing aluminum (1000K thick) on a polyimide film (70 μm thick) containing conductive carbon to form a 6 μm ink layer and conduct electricity. A molded heat-sensitive transfer recording sheet was manufactured. Using this sheet, you can use the current-carrying thermal printer Quietwrites (product name,
(manufactured by 18M) on bond paper.

When evaluated in the same manner as in Example 1, it was confirmed that light in the near-infrared region was sufficiently absorbed.

Example 3 Xylene 63 parts Butanol 30 parts Hytanol // 3,1' 1 part (Novolac resin manufactured by Hitachi Chemical) Compound of layer 3
The above components (3 parts, total 100 parts) were sufficiently stirred and mixed at room temperature to obtain an oil-based marker ink. This ink was filled into a felt pen and printed on electrophotographic paper. It was evaluated in the same manner as in Example 1, and it was confirmed that light in the near-infrared region was sufficiently absorbed.

Examples Gtoluene 59 parts Isopropyl alcohol 70 parts Nitrocellulose 1 part Hallinister KT-
22/part total 100 parts The above components were sufficiently stirred and mixed at room temperature to obtain an ink for flexible printing. This ink was used to print on cardboard using a flexo printing machine.

When evaluated in the same manner as in Example 1, it was confirmed that light in the near-infrared region was sufficiently absorbed.

Claims (1)

[Claims] (1) Organic solvent and/or wax and the following general formula [I
]▲There are mathematical formulas, chemical formulas, tables, etc.▼[I] (In the formula, R^1 and R^2 represent a substituted or unsubstituted lower alkyl group, and X represents a hydrogen atom, a halogen atom, a lower alkyl group, a lower represents an alkoxy group or an acylamino group, Y represents a hydrogen atom, a halogen atom, or a lower alkyl group, m represents 2 or 3, Z represents a halogen ion,
Acetate ion, ClO_4^-, BF_4^-, PF_6
^-, or represents a tetraphenylporane ion. ) An oil-based ink that absorbs near-infrared rays and is characterized by containing a nickel complex represented by: