JPH07106671B2 - Desensitizing ink for pressure-sensitive copying paper - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention is a desensitizing ink for pressure-sensitive copying paper, particularly, there is no image reversion due to water, excellent printability, improved desensitizing effect and set-off property. Desensitizing ink for pressure-sensitive copying paper.

(Prior Art) A color image is obtained by a reaction between an electron-donating or proton-accepting colorless organic compound (hereinafter referred to as a color former) and an electron-accepting or proton-releasing property (hereinafter referred to as a developer). It has been known for a long time.

As a concrete use of this phenomenon, pressure-sensitive copying paper (for example, US Pat. Nos. 2505470, 2505489, and 2550471) is disclosed.
No., No. 2548366, No. 2712507, No. 2730456, No. 27304
No. 57, No. 3418250, No. 3672935), thermal recording paper (for example, Japanese Patent Publication No. 43-4160, No. 43-7600, No. 45-14039,
US Patent No. 2939009) and the like. Furthermore, a printing method is known in which an ink containing a color-developing agent is supplied to a sheet coated with a color-developing agent to obtain a colored image (German Patent Application (OLS) 1
No. 939962).

The color developer has the properties defined previously, and examples thereof include clays, phenol resins, and metal salts of aromatic carboxylic acids.

In general, in pressure-sensitive copying paper, a combination of a microcapsule-containing layer containing the above-mentioned color-forming agent and a developer layer is used to obtain a color-developed image. By destroying the microcapsules and bringing the color former and the color developer into contact with each other.

Generally, these color developers are used as a color developer sheet uniformly applied to the entire surface of the support. However, depending on the purpose of use of the pressure-sensitive copying paper, the color developer sheet may have a recording-free portion. In such a case, a desensitizing ink containing a desensitizing agent is applied to that portion of the developer sheet by a printing machine or the like for desensitization.

Desensitizing inks used for such purpose include, for example, U.S. Pat. No. 2777780, Japanese Patent Publication Nos. 44-27255, and 45-21.
No. 448, No. 46-22652, No. 46-26546, JP-A-47-329
No. 15, JP-B-47-38201, JP-B-48-4050, JP-A-48-6
No. 805, Japanese Patent Publication No. 49-4484, No. 49-19647, No. 49-2300
No. 8, No. 49-23850, No. 49-43708, No. 49-72009.
No. 49, No. 7777709, No. 49-77710, No. 49-15513,
No. 49-83509, German patent application (OLS) 2343800, No. 2
No. 359079, No. 2361856, Japanese Patent Publication No. 58-38119, JP-A No. 63
-74681, JP-A-63-41184 and the like.

(Problems to be Solved by the Invention) Desensitizing inks used for the above purpose generally include a desensitizing agent and a pigment such as titanium dioxide, a binder, and a diluent such as an organic solvent as necessary. It has not been found that the ink has an excellent desensitizing effect on various color developers and has a good set-off property. Also, when a desensitizer with high water solubility is used, an image reversion occurs due to water, and conversely, when a desensitizer that is insoluble in water is used, the printed area is not uniform when used in offset printing. Had become the ink of.

Therefore, an object of the present invention is to provide a desensitizing ink for pressure-sensitive copying paper which is excellent in printability and has an excellent desensitizing effect for various color developers, and which has a good set-off property and does not cause image retention due to water. To do.

(Means for Solving the Problems) The above object is achieved by the present invention described below.

That is, the present invention relates to a desensitizing ink containing a desensitizing agent, a pigment and a binder, which is an alkylene oxide adduct of 4 to 70 mol per 1 mol of 1,2-diaminopropane as a desensitizing agent, A desensitizing ink for pressure-sensitive copying paper, which comprises an adduct in which 40 mol% or more of the alkylene oxide is butylene oxide.

As the alkylene oxide, 40 mol% or more needs to be butylene oxide, but the remaining 60 mol% or less can be ethylene oxide, propylene oxide, butylene oxide, styrene oxide, or the like,
Preferred are propylene oxide and butylene oxide.

This desensitizer has characteristics such as low viscosity which is considered to be due to branching of the alkyl group, or good stability with the resin. It can be effectively used in combination with a conventionally known desensitizer.

As the pigment used in the present invention, white pigments such as titanium dioxide, barium sulfate, calcium carbonate, talc, kaolin, and bentonite are used.

The binder used in the present invention is a rosin-modified phenol resin, a ketone resin, a polyamide resin, a maleic acid resin,
Natural or synthetic polymer compounds such as phenol resin, epoxy resin, alkyd resin, melamine resin, urea resin, nitrocellulose, ethyl cellulose, butyral resin, polyvinyl alcohol, gelatin and shellac are used.

The desensitizing ink of the present invention can be used only with the above composition, but if necessary, an organic solvent may be used as a diluent. Examples of the organic solvent include linseed oil, tung oil, soybean oil, cottonseed oil, methanol, ethanol, ethyl acetate, toluene, hexane, methyl ethyl ketone, methyl isobutyl ketone, polypropylene glycol, polybutylene glycol, paraffin oil and the like.

The desensitizing ink of the present invention may also optionally contain waxes such as paraffin wax, microcrystalline wax, carnauba wax, etc., anti-setoff agents such as starch and dextrin, ultraviolet absorbers, antioxidants and the like. .

(Example) To 40 parts by weight of the desensitizer shown in Table 1, 17 parts by weight of a rosin-modified phenolic resin (Tamanol T135 manufactured by Arakawa Chemical Co., Ltd.) was added and dissolved at 150 ° C. After cooling this lysate to 25 ° C,
Titanium dioxide (25 parts by weight) and white spindle oil (18 parts by weight) were added and kneaded with a three-roll mill to obtain desensitizing inks for offset and letterpress.

As the test paper, a commercially available pressure-sensitive copying paper lower paper (Fuji pressure-sensitive paper = Fuji Photo Film Co., Ltd.) was used.

Ink evaluation is 100% after printing 3g / m ² of the above desensitizing ink.
After applying a load of g / cm ² and combining with the lower paper for one week, the transfer to the lower paper is evaluated as “set-off”, and the printed surface and the upper paper (commercially available Fuji pressure paper) are overlaid. Then, the entire surface was subjected to color development with a super calendar to evaluate the "desensitizing effect" and the "uniformity" of the desensitizing effect.

(Effect of Invention) The desensitizing ink according to the present invention is excellent in printability, set-off property and desensitizing effect.

Claims (1)

[Claims] 1. A mole of 1,2-diaminopropane,
A desensitizing ink for pressure-sensitive copying paper, which is an alkylene oxide adduct of 4 to 70 mol, wherein 40 mol% or more of the alkylene oxide contains an adduct which is butylene oxide.