JP2656827B2 - Desensitizing ink - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a desensitizing ink for pressure-sensitive copying paper having excellent light fastness and desensitizing properties.

2. Description of the Related Art Pressure-sensitive copying paper is composed of an electron-donating colorant such as crystal violet lactone (hereinafter simply referred to as a colorant) and an electron-accepting colorant such as a polyvalent metal salt of an aromatic carboxylic acid (hereinafter referred to as a colorant). , Which is simply referred to as a coloring agent). The upper paper in which the coloring agent-containing microcapsules are applied to the back surface of the base paper, and the lower paper in which the coloring agent is applied to the surface of the base paper, are each used. This is a recording method in which a color image is formed on a lower sheet by pressing the surface of the upper sheet with a typewriter or the like so that the application surfaces are opposed to each other.

Further, when copying a large number of sheets, insert the necessary number of intermediate sheets between the upper sheet and the lower sheet, with the coloring agent applied to the front surface of the base paper and the microcapsule coating liquid applied to the back surface. Thus, a large number of copies can be obtained.

Further, as a kind of pressure-sensitive copying paper, there is a so-called single pressure-sensitive copying paper in which the microcapsule layer and the colorant are formed as a laminated or mixed layer.

However, when pressure-sensitive copying paper is used for a voucher or the like, it is necessary to prevent characters or the like to be written on the first paper of a plurality of stacked vouchers from being copied to a specific portion of other lower paper. Often required. In response to such demands, desensitizers have been developed to inhibit the color reaction by chemically reacting with a color former or a color former in order to prevent the color development of a specific portion of the pressure-sensitive copying paper. Is formed into an ink with a suitable vehicle and printed on the colorant-coated surface.

Such desensitizers or desensitizing inks are described, for example, in JP-B-55-10397, JP-A-52-52706, and JP-A-52-60713.
No., JP-A-52-62512, JP-B-56-42479, JP-B-Showa 60
-50599, JP-B-61-7954, JP-B-61-2515, JP-B-63-56877, JP-B-63-63396, and JP-B-63-1267
Various proposals have been made in Japanese Patent Publication No. 82 and the like.

However, conventional desensitizing inks still have various problems in practical use. That is, the desensitizing ability is reduced under various conditions such as light, heat, and humidity, and the desensitizing agent applied to a specific portion of a desired sheet is heated or the like. And there is a drawback that the desensitizing effect spreads to places other than the necessary places.

Further, there is a disadvantage that the portion where the desensitizing ink is applied is colored brown by light.

Various improvements have been proposed to overcome the drawbacks of such desensitizers. However, sufficient effects cannot be obtained, and new drawbacks accompany the improvements. Not obtained.

"Problems to be Solved by the Invention" It is an object of the present invention to solve the above problems and to provide a desensitizing ink for pressure-sensitive copying paper having excellent desensitizing properties.

"Means for Solving the Problems" The present invention provides a compound represented by the following general formula (I) and / or
Or a desensitizing ink for pressure-sensitive copying paper, comprising a compound represented by the general formula (II) and a desensitizing agent.

(In the formula, R ₁₁ and R ₂₁ each represent a hydrogen atom, an alkyl group, a phenyl group, or an aralkyl group which may have a substituent, and n represents an integer of 1 or more.) (Wherein R ₁₂ and R ₂₂ each represent a hydrogen atom, an alkyl group, a phenyl group, or an aralkyl group which may have a substituent, and m represents an integer of 1 or more.) Specific examples of the hydroxyphenylbenzotriazole-based compound represented by the general formula (I) or (II) to be used include compounds having a combination of AE shown in Table 1 with substituents.

However, in the general formula, n or m is an integer of 1 or more, and although not particularly limited, an integer of usually about 1 to 100 is preferable.

 These compounds may be used in combination of two or more.

These compounds have the ability to absorb ultraviolet light and also have a desensitizing ability because they have a polyether structure in the molecule. Therefore, even when light is applied to the area where the desensitizing ink is applied, the phenomenon of desensitization ability or coloring is suppressed, and an excellent desensitizing effect can be obtained. Moreover, since these compounds have excellent hydrophobicity, they have good compatibility with the vehicle of the ink and do not hinder the dispersion of the pigment when a pigment such as titanium oxide is added to the ink.

In the present invention, a desensitizer (not containing the compound represented by the above general formula) is further contained in the ink to obtain a more excellent desensitizing effect. Examples of such a desensitizer include various known desensitizers described in the above-mentioned publications, such as an alkylene oxide adduct of an amine, an alkylene oxide adduct of an alkanolamine, and an alkylene oxide adduct of a polyol.

The compound represented by the general formula is preferably a desensitizer 10
1 to 50 parts by weight, more preferably 5 to 30 parts by weight with respect to 0 parts by weight
It is desirable to add in the range of about parts by weight.

Other vehicles for preparing desensitizing inks include:
Dry oil such as linseed oil, synthetic dry oil such as maleic oil, mineral oil, paraffin oil, etc. and synthetic resin such as ethylcellulose, nitrocellulose, alkyd resin, polyamide resin, acrylic resin, etc. are used by mixing one or more kinds. Is done.

As the pigment, titanium oxide, zinc oxide, barium sulfate, magnesium carbonate, calcium carbonate, barium carbonate, magnesium hydroxide, conventionally known pigments such as talc,
One type or a mixture of two or more types is used.

The mixing ratio of the vehicle (including the resin) and the pigment to the ink is appropriately selected depending on the type of the compound of the general formula and the desensitizer, and is not particularly limited. The total amount of the vehicle and the pigment is preferably about 20 to 150 parts by weight based on 100 parts by weight of the compound and the desensitizer in total.

Further, if necessary, other ultraviolet absorbers, antioxidants and the like are appropriately selected and used in the ink.

The method for preparing the ink is not particularly limited, either. The ink is prepared by dissolving the compound represented by the above general formula in a desensitizer or a vehicle in advance and mixing the components.

The amount of the desensitizer applied to the colorant-containing layer surface of the pressure-sensitive copying paper varies depending on the type of the electron-accepting substance, the type of the desensitizer and the method of application, but is not particularly limited. Usually, it is desirable to use the desensitizer in an amount of about 0.1 to 5 g / m ² , preferably 0.5 to ² g / m ² .

"Examples" Examples of the present invention will be described below, but are not limited thereto. Parts and% in Examples are parts by weight and% by weight, respectively, unless otherwise specified.

Example 1 Vehicle consisting of 40 parts of desensitizer (ethylenediamine-butylene oxide adduct), modified linseed oil and ketone resin
25 parts, 25 parts of titanium oxide, and 10 parts of a mixture of compounds represented by formulas (I) and (II) (wherein R ₁₁ and R ₁₂ are hydrogen atoms and R ₂₁ and R ₂₂ are methyl groups). A desensitizing ink was prepared. Using a RI tester (Meiji Seisakusho), apply this ink to the color former-containing layer of the medium paper (trade name: KS Copy Bright, manufactured by Kanzaki Paper Co., Ltd.) of pressure-sensitive copying paper using a filling amount of 3 g / m ^2.
To obtain a medium sheet on which desensitized printing was performed.

Example 2 50 parts of a desensitizer (ethylenediamine-propylene oxide adduct), 25 parts of a copolymerized part of styrene and linseed oil, 20 parts of titanium oxide, compounds represented by the general formulas (I) and (II) (Wherein R ₁₁ R ₁₂ is a t-butyl group and R ₂₁ and R ₂₂ are hydrogen atoms). A medium paper subjected to desensitization printing in the same manner as in Example 1 except that a desensitizing ink comprising 5 parts was prepared. Obtained.

Comparative Example 1 A medium sheet subjected to desensitization printing was obtained in the same manner as in Example 1 except that the compound represented by the general formula was not used.

Comparative Example 2 A medium sheet subjected to desensitization printing was obtained in the same manner as in Example 2 except that the compound represented by the general formula was not used.

Comparative Example 3 2- (3,5-di-tert-butyl-2-) having no polyether structure in the molecule instead of the compound represented by the general formula
An ink was prepared in the same manner as in Example 1 except that (hydroxyphenyl) -5-chlorobenzotriazole was used, and a desensitized printing medium paper was obtained.

Using the five types of middle papers thus obtained, the following performance comparison test was performed, and the results are shown in Table 2.

Desensitization effect The desensitized printing portion of the medium paper was superposed on the upper paper (manufactured by Kanzaki Paper Co., Ltd.) so that the surface of the coloring agent-containing layer was opposed to each other, and the color development of the desensitized printing portion when printing with a typewriter was determined. The less the color of the desensitized print portion is, the better.

Lightfastness I After irradiating the desensitized printing area of the medium paper with ultraviolet light for 5 hours using a fade meter, superimpose the upper paper so that the coloring agent-coated surfaces of the upper paper face each other, and print with a typewriter. Was determined. The one without coloring is better.

Lightfastness II The desensitized printing portion of the medium paper and the color-developed surface of the upper paper were overlapped so as to face each other, printing was performed with a typewriter, and then the desensitized printing portion was processed with a fade meter for 5 hours. The degree to which the desensitizing effect was maintained was determined. The less the coloring, the better the light resistance.

"Effects" As is clear from the results in the table, the desensitizing ink of the present invention was an excellent desensitizing ink having excellent desensitizing effects and light fastness, and also having high ink stability.

Claims (1)

(57) [Claims] 1. A compound represented by the following general formula (I) and / or
Or a desensitizing ink for pressure-sensitive copying paper, comprising a compound represented by formula (II) and a desensitizing agent. (In the formula, R ₁₁ and R ₂₁ each represent a hydrogen atom, an alkyl group, a phenyl group, or an aralkyl group which may have a substituent, and n represents an integer of 1 or more.) (In the formula, R ₁₂ and R ₂₂ each represent a hydrogen atom, an alkyl group, a phenyl group, or an aralkyl group which may have a substituent, and m represents an integer of 1 or more.)