JPH04293979A - Desensitizing ink for pressure-sensitive copying paper - Google Patents

Abstract

PURPOSE:To prepare the title ink which is suitable for wet offset printing by incorporating a specific maleic acid resin into the ink. CONSTITUTION:A maleic acid resin prepd. by reacting 100 pts.wt. rosin, 2-10 pts.wt. maleic anhydride, and 1-15 pts.wt. polyol (e.g. glycerol) is incorporated into the title ink.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a desensitizing ink for pressure-sensitive copying paper, and more particularly to a desensitizing ink for pressure-sensitive copying paper that is suitable for wet offset printing.

0002

[Prior Art] A colored image is obtained by the 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 color developer). This has been known for a long time.

[0003] As a concrete application of this phenomenon,
Pressure-sensitive copying paper (e.g., U.S. Pat. No. 2,505,470;
No. 05489, No. 2550471, No. 2548366
No. 2712507, No. 2730456, No. 27
No. 30457, No. 3418250, No. 3672935
No.), thermal recording paper (for example, Japanese Patent Publication No. 43-4160, No. 43-7600, No. 45-14039, U.S. Patent No. 2)
939009), etc. Furthermore, a printing method is also known in which a colored image is obtained by supplying ink containing a color former to a sheet coated with a color developer (German Patent Application (OLS) 19
No. 39962).

[0004] Color developers have the properties defined above, and include clays, phenolic resins, metal salts of aromatic carboxylic acids, and the like. In general, pressure-sensitive copying paper
To obtain a colored image, a combination of the above-mentioned microcapsule-containing layer containing a coloring agent and a color developer layer is used, and these layers are brought into contact and the microcapsules are destroyed by pen pressure, typing pressure, etc., and color development occurs. This is done by bringing the color developer into contact with the color developer.

Generally, these color developers are used as a color developer sheet that is uniformly applied to the entire surface of the support, but depending on the purpose of use of the pressure-sensitive copying paper, there may be areas on the side of the color developer sheet that do not require recording. In such cases, a method of desensitizing the color developer sheet by applying desensitizing ink containing a desensitizing agent to that portion of the color developer sheet using a printing machine or the like is used.

Desensitizing inks used for this purpose are described in, for example, US Pat. No. 2,777,780 and Japanese Patent Publication No.
No. 4-27255, No. 45-21448, No. 46-2
No. 2651, No. 46-29546, JP-A-47-32
No. 915, Special Publication No. 47-38201, No. 48-405
No. 0, Japanese Patent Publication No. 48-6805, Special Publication No. 49-4484
No. 49-19647, JP-A-49-43708, JP-A-49-72009, JP-A-49-77709, JP-A-4
No. 9-77710, No. 49-15513, No. 49-8
No. 3509, German patent application (OLS) 2343800
No. 2359079, No. 2361856, Japanese Patent Publication No. 58-38119, Japanese Patent Application Laid-open No. 41184-1984, Japanese Patent Application Laid-open No. 74681-1984, etc.

[0007]

[Problems to be Solved by the Invention] Desensitizing inks used for the above purpose generally contain a desensitizer, a pigment such as titanium dioxide, a binder, and if necessary a diluent such as an organic solvent. No desensitizing ink has been found that has an excellent desensitizing effect against various color developers and is also suitable for wet offset printing. Furthermore, as a binder suitable for wet offset printing, it is most effective to use rosin-modified phenolic resin, which is rich in lipophilic properties, but when used as a binder for desensitizing inks, most of the desensitizer is a lipophilic substance, so resin and the desensitizer have poor compatibility. Therefore, when a desensitized ink is used, problems such as scumming and poor transfer occur during wet offset printing, and printing manufacturers have desired the development of a desensitized ink that is suitable for wet offset printing. The present invention improves the various drawbacks mentioned above and provides a desensitizing ink for pressure-sensitive copying paper that has good scumming resistance and transferability during wet offset printing, and has an excellent desensitizing effect. be.

[0008]

[Means for Solving the Problems] The present invention provides rosin 100
2 to 10 parts of maleic anhydride, 120 to 240°C,
Preferably, the resulting resin is reacted at 180°C to 200°C, and 1 to 15 parts of polyol is added to 100 parts of this resin.
This desensitizing ink for pressure-sensitive copying paper is characterized by containing a maleic acid resin obtained by reaction at 20 to 240°C, preferably 180 to 200°C.

The maleic acid resin used in the present invention is obtained by reacting rosin with maleic anhydride to produce a rosin-maleic anhydride adduct, and then esterifying it with a polyol. It may be obtained by a method of reacting with rosin after chemical reaction, or a method of reacting rosin, maleic anhydride, and polyol simultaneously. Examples of the polyol used in the above reaction include glycerin, trimethylolethane, trimethylolpropane, tris-ethylbiloxy isocyanurate, pentaerythritol diglycerin, ethylene glycol, neopentyl glycol, dipentaerythritol, tripentaerythritol, and the like. .

The maleic acid resin used in the present invention has a wide range of solubility in solvents and exhibits good compatibility even when combined with known desensitizers. As the pigment used in the present invention, white pigments such as titanium dioxide, barium sulfate, calcium carbonate, talc, kaolin, and bentite are used.

The desensitizing ink of the present invention can be used with the above composition alone, 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 acid, toluene, hexane, methyl ethyl ketone, methyl isobutyl ketone, polypropylene glycol, polybutylene glycol, and paraffin oil.

The desensitizing ink of the present invention may also contain waxes such as paraffin wax, microcrystalline wax, carbanal wax, and polyethylene wax, anti-set-off agents such as starch, and dextrin, if necessary.
It can contain ultraviolet absorbers, antioxidants, etc.

[0013]

[Examples] The present invention will be explained below with reference to Examples. In the examples, "part" means part by weight, and "%" means % by weight. Example 1 4 moles of propylene oxide was added to 1 mole of ethylenediamine, and 20 parts of maleic acid resin (manufactured by Arakawa Chemical Co., Ltd., Draffix 4102) was added to 60 parts of a desensitizer obtained by reacting and esterifying 3 moles of lauric acid. The mixture was dissolved, 20 parts of titanium oxide was added thereto, and the mixture was milled using a three-roll mill to obtain a desensitized ink.

Example 2 Maleic acid resin (
15 parts of Harimak 145P (manufactured by Harima Kasei Kogyo Co., Ltd.) and 5 parts of rosin-modified phenol resin (Harima Kasei Kogyo Co., Ltd. Hariphenol P-120) were dissolved, 20 parts of titanium oxide was further added, and the mixture was milled using a three-roll mill. A desensitized ink was obtained.

Example 3 10 moles of ethylene oxide was added to 1 mole of ethylenediamine, and 65 parts of a desensitizer was esterified by the reaction with 2 moles of myristic acid, and 15 parts of a maleic acid resin (Harima Kasei Kogyo Co., Ltd., Harimac 135GN) was added. dissolve the part,
Furthermore, 20 parts of titanium oxide was added and milled using a three-roll mill to obtain a desensitized ink.

Example 4 To 65 parts of the desensitizer used in Example 3, maleic acid resin (
Marquid No. manufactured by Arakawa Chemical Industry Co., Ltd. 6) 10 parts of rosin-modified phenolic resin (Tamanol 362, manufactured by Arakawa Chemical Industries, Ltd.) were dissolved, 20 parts of titanium oxide was further added, and the mixture was kneaded in a three-roll mill to obtain a desensitizing ink.

Comparative Example 1 Rosin-modified phenol resin (Tamanol T135 manufactured by Arakawa Chemical Co., Ltd.) was added to 60 parts of the desensitizer used in Example 1.
20 parts of the solution was dissolved, 20 parts of titanium oxide was further added, and the mixture was milled using a three-roll mill to obtain a desensitized ink.

Comparative Example 2 Rosin-modified phenol resin (Harima Kasei Kogyo Co., Ltd. Hariphenol P1) was added to 60 parts of the desensitizer used in Example 1.
10) Dissolve 20 parts and further add 20 parts of titanium oxide,
It was milled using a three-roll mill to obtain a desensitized ink.

Comparative Example 3 Rosin-modified phenol resin (Tamanol T135 manufactured by Arakawa Chemical Co., Ltd.) was added to 65 parts of the desensitizer used in Example 3.
15 parts of the solution was dissolved, 20 parts of titanium oxide was further added, and the mixture was milled using a three-roll mill to obtain a desensitized ink.

(Test method) Examples 1, 2, 3, 4,
Each desensitizing ink obtained in Comparative Examples 1, 2, and 3 was subjected to RI.
Using a tester, the ink was developed on the developer-coated surface of commercially available carbonless paper so that the ink coating amount was 3 g/m2. The surface coated with the coloring agent was superimposed on the surface coated with this ink, and the state of color development was evaluated by printing with a typewriter. Furthermore, each desensitizing ink was printed using an offset printing machine to determine the ease of printing. The test results are shown in Table 1. In addition, in the table, ○ in the desensitizing effect indicates that the desensitizing effect is good with no color development during typewriter printing, and × indicates that the desensitizing effect is insufficient due to color development. In addition, ○ in printability indicates that printing is possible without any problems, and × indicates that practical printed matter cannot be obtained due to stains, poor transfer, etc.

[0021]

[Table 1] Table 1 shows that the desensitizing ink for pressure-sensitive copying paper according to the present invention has excellent suitability for offset printing and has an excellent desensitizing effect.

Claims (2)

[Claims] 1. A desensitizing ink for pressure-sensitive copying paper, comprising a maleic acid resin obtained by reacting rosin, maleic anhydride, and a polyol. 2. The desensitizing ink for pressure-sensitive copying paper according to claim 1, which contains a maleic acid resin obtained by reacting 100 parts by weight of rosin, 2 to 10 parts by weight of maleic anhydride, and 1 to 15 parts by weight of polyol.