JPS6155549B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a penetrant-drying ink composition that, when printed on a permeable substrate such as paper, provides a printed layer that can be easily erased or discolored or faded by the frictional force of an eraser or the like. .

After printing a background pattern on cash certificates such as stock certificates, checks, promissory notes, gift certificates, lottery tickets, commuter passes, and train tickets, amounts or numbers are written using a printed check writer, ballpoint pen, fountain pen, etc. Conventionally, in order to cope with the falsification of these written characters using an ink eraser, it has been widely practiced to use ink that erases, discolors, or develops color due to the oxidation effect of the ink eraser to print background patterns. . For example, as an example of such a tamper-preventing ink, one is known that utilizes the property of ordinary dyeing lakes to change color and fade when exposed to commercially available ink erasers, acids, alkalis, oxidizing agents, and the like. (Printing Ink Engineering, edited by Takeshi Shioji, p. 422, published by the Printing Society Publishing Department). Other known inks for preventing oxidation include those that utilize the coloring properties of dyes such as guanidine and thiazole when erased by ink, and those that utilize the coloring properties of certain dyes and pigments that are exposed to ultraviolet rays.

However, in recent years, as ballpoint pen inks and the like that can be erased with erasers have become commercially available, it has become necessary to take measures to prevent the above-mentioned cash voucher amounts from being tampered with using erasers. For this purpose, it is sufficient to use ink that provides a printed background pattern that can be erased with an eraser or changed in color or faded. However, the conventional type of anti-tamper ink described above does not provide a printed background pattern that can be easily erased with an eraser.

The main object of the present invention is to provide a printing ink that can be easily erased by an eraser, and by printing a background pattern on cash notes, it is easy to detect tampering with the eraser. It's about doing. According to research conducted by the present inventors, this purpose can be achieved by using pigments of 30 to 60% of the present invention.
(wt%. Same below) and antioxidant 0.5-3.0%
It has been found that this can be achieved by a penetrant-drying ink composition characterized by comprising: and a vehicle mainly composed of vegetable oil.

The ink composition of the present invention is compositionally quite different from conventional printing inks and has the following characteristics. First, it contains a large amount of pigment, 30-60%. This is because there is a lot of pigment on paper such as coupons,
This is to form a printed layer with a low resin content and therefore with pigment exposed on the surface, making it easier to erase with an eraser. Second, a vehicle based on vegetable oil is used. This is because, as mentioned above, the ink is high in pigment content and low in resin content, and the vegetable oil has excellent vehicle properties in order to provide excellent printability. Furthermore, since vegetable oil has excellent wetting properties for pigments, the practically inconvenient yoking phenomenon can be avoided. Third
It also contains antioxidants (desiccating agents) in a much larger amount, at 0.5 to 8.0%, compared to the usual 0.1%. This suppresses the oxidative polymerization of vegetable oil on the paper, giving sufficient time for a considerable portion of the vehicle to penetrate into the paper, and also allows the vegetable oil remaining on the paper to completely polymerize and harden to form a strong film. This is to prevent The ink composition of the present invention includes:
As mentioned above, it provides a printed layer having a film strength weakened to the extent that it can be erased with an eraser, but is characterized in that it avoids inconveniences such as scuffing during printing, set-off after printing, and blocking.

The present invention will be explained in more detail below.

The ink composition of the present invention contains 30 to 60% of a pigment consisting of a coloring pigment and an extender. When the printed area of the composition of the present invention requires only erasability with an eraser, examples of coloring pigments include Carmine 6B, Phthalocyanine Blue, Phthalocyanine Green, Disazo Yellow, Lake Red C, Lake Red D, Watching Red, and Naphthol. Common organic and inorganic pigments such as red, Bordeaux 10B, fast sky blue, navy blue, yellow lead, red iron, titanium yellow, and molybdenum red can also be used. However, in order to make the ink composition of the present invention more excellent in preventing tampering, it is preferable that the printed area has erasability by oxidation action of ink eraser. For this purpose, as a coloring pigment, a basic dye is used, which is obtained by precipitating a basic dye with a precipitant such as phosphotungstic acid, phosphomolybdic acid, phosphotungsten-molybdic acid, tannic acid, synthetic tannic acid, or a salt thereof. Rakes are particularly preferably used. Examples of these basic dye lakes include dye lakes such as Aufmin, Rhodamine, Bismarck Brown, Victoria Blue, Methyl Violet, Malachite Green, Quinoline Yellow, Tartrazine Yellow, and Eosin. In addition, some of the pigments in the ink composition of the present invention include calcium carbonate, magnesium carbonate, barium sulfate, alumina white, finely powdered silica, or natural silicates (kaolin, clay, talc, organic bentonite, etc.). Use pigments. These extender pigments work by weakening the ability of the vehicle to stick to the printed surface and making it easier to erase with an eraser, but at the same time, when using an ink eraser, they make it easier for the ink eraser to penetrate into the ink film, making it difficult for the dye lake to penetrate. It also has the function of facilitating oxidative bleaching. Extender pigments can also be pretreated with stearic acid, rosin, etc. in order to improve fluidity.

The larger the amount of these pigments used, the weaker the formation of the printed film will be, and when using an eraser or basic dye lake, it will be easier to erase with an ink eraser, but if too large a quantity is used, the printed film will become weaker. This is undesirable because it causes a so-called yoking phenomenon, and the color fades due to simple mechanical friction, mere rubbing by fingertips, etc. Therefore, the total amount of pigment contained in the ink composition of the present invention is 30 to 60%. Of these, as coloring pigments, it varies depending on the material used, but in the case of dye lakes, it is 1 to 30%,
Usually, 5 to 25% is suitably used from the viewpoint of coloring strength and the like.

In addition, the extender pigment content is 10 to 50%, preferably 25 to 40%.
Used in a range of %. Two or more types of coloring pigments and extender pigments can be used in combination.

However, among extender pigments, finely powdered silica, organic bentonite, etc. have a large oil absorption capacity, so they are used in the range of 0.5 to 5.0%, preferably 1.0 to 3.0%, and used in combination with other extender pigments.

The ink composition of the present invention contains an antioxidant from 0.5 to
It contains 3.0%, particularly preferably 0.8 to 1.2%. This is a significantly higher amount than the 0.01-0.3% contained in normal printing inks. This antioxidant is used to prevent or suppress the formation of a strong film due to the oxidative polymerization reaction of vegetable oil, which will be described later. That is, vegetable oil absorbs oxygen in the air to generate peroxide, and a chain reaction of radicals generated by its decomposition forms a polymer film. Antioxidants inhibit these oxidative polymerization processes, and include phenolic and amine antioxidants that capture generated radicals and inhibit the progress of radical chain reactions, and A sulfur-based product that decomposes peroxide without generating radicals.
There are phosphorus-based antioxidants. Any type of antioxidant can be used as the antioxidant in the present invention; Therefore, phenolic antioxidants are preferred. Examples of preferred phenolic antioxidants include hydroquinone, catechol, guaiacol, eugenol, 2,6-di-t-butyl-p
-Cresol (BHT), butylhydroxylanisole (BHA), 2,6-t-butyl-4-
Ethylphenol, stearyl-3-(3,5-
di-t-butyl-4-fluoroxyphenyl) propionate, 2,2'-methylene-bis-(4-methyl-6-t-butylphenol), 2-2'-methylene-bis-(4-ethyl -6-t-butylphenol), 4,4'-thiobis-(3-methyl-6
-t-butylphenol), 4,4'-butylidene-bis(3-methyl-6-t-butylphenol), 1,1,3-tris-(2-methyl-4-hydroxy-5-t-butylphenol) ) butane, tetrakis-[methylene-3-(3',5'-di-t-butyl-4'-hydroxyphenyl)propionate]methanthocopherol, and the like.

The ink composition of the present invention contains vegetable oil as the main vehicle component. Vegetable oils that can be used include linseed oil, eno oil, tung oil, flaxseed oil, safflower oil, oiticica oil, kaya oil, walnut oil, poppy oil,
Drying oils such as sunflower oil; semi-drying oils such as soybean oil, cottonseed oil, corn oil, sesame oil, rapeseed oil, rice bran oil; non-drying oils such as peanut oil, olive oil, camellia oil, castor oil, sasanquat oil; or These fatty acids as well as polymerized varnishes such as sulfurized oils obtained by adding sulfur to these fatty acids and polymerizing them by heating are included. Drying oils such as linseed oil, tung oil, dehydrated castor oil, sunflower oil, or polymerized varnishes of these drying oils are used from the viewpoint of printability, pigment dispersibility, ink viscosity, fluidity, and appropriate adhesion to paper. It is preferable to use semi-drying oil or non-drying oil together with semi-drying oil or non-drying oil.

These vegetable oils are used as the main vehicle component in the ink composition of the present invention,
The amount of 10 to 50
%, more preferably 30-45%.

It is preferable that the ink of the present invention does not contain a resin component that forms a hard printing film, but in order to fix the pigment to some extent on the paper, natural rosin, dimer rosin, rosin ester, copal, gilsonite, general petroleum resin, etc. For example, resins with relatively small molecular weights such as various fatty acid-modified alkyd resins are
It is also possible to add up to about %.

In addition, in order to facilitate the mixing of the aforementioned antioxidant into the ink, we added the antioxidant to Nisseki 540.
Or 10-20% dissolved in petroleum-based high boiling point solvents used in ordinary letterpress or lithographic inks such as 590 Solvent, Mitsubishi 280 Solvent, spindle oil, etc.
It can be added to the ink of the invention as a concentrated solution. That is, the ink of the present invention has the above-mentioned vegetable oil (or a component derived therefrom) as the main vehicle component (usually 20% or more of the ink, and 50% or more of the vehicle), but the vegetable oil is used for dilution purposes. It is permissible to use mineral oil such as a petroleum solvent within the range that it is a main component, or to mix in a small amount of the above-mentioned low molecular weight resin.

Furthermore, it has been found that it is preferable in some cases to mix approximately 0.1 to 5.0% of water into the ink of the present invention. In other words, by mixing water,
Since water is adsorbed to the pigment in preference to vegetable oil, the pigment is easily separated from the vehicle mainly composed of vegetable oil, which has the effect of inhibiting the formation of a strong printing film. Therefore, erasing with an eraser or ink eraser becomes easy. As a method for mixing water into the ink, for example, water may be added dropwise while stirring the ink strongly with a dissolver or homo mixer at about 800 to 1500 rpm. Also, at this time, substances with surfactant action such as glycerin, polyhydric alcohols, surfactants, cellulose derivatives, silicates, borates, etc. are added to the water or ink to help disperse and mix the water. Good too.

In the ink of the present invention, a surfactant can be added as a dispersant or a stain preventive agent, and other additives that are added to ordinary printing ink compositions can also be added as appropriate.

The ink composition of the present invention can be produced by directly applying the method for producing ordinary letterpress or lithographic inks. That is, for example, a pigment is mixed with a part of a vehicle, and after being mixed and dispersed using a conventional three-roll, shot mill, etc.,
Furthermore, an antioxidant, other optional additives, and the remainder of the vehicle may be added and further mixed using a dissolper or the like.

The obtained ink composition of the present invention can be used to apply a tint pattern around the marking area to prevent the tampering of cash vouchers by various printing methods such as flat plate printing, rotary letterpress printing, sheet-fed printing plate offset, and printing plate offset printing. If this is formed, it is possible to impart anti-tampering effects to the cash vouchers.

In the foregoing, the ink composition of the present invention has been primarily described in relation to its use in preventing tampering. However, the ink composition of the present invention is useful in general in the production of printed matter in which it is desirable to erase printed areas with an eraser or, in addition, with an ink eraser. Examples of such uses include educational printed materials (question and answer sheets, hidden pictures, quiz sheets), and the like.

The present invention will be specifically described below with reference to Examples.
In the examples, "parts" and "%" are both based on weight.

Example 1 Letterpress and lithographic sheet-fed printing inks were kneaded using three rolls to prepare an ink having the following composition.

950 Bright Green LB (manufactured by Daido Kasei Co., Ltd.) 10 parts Hakuenka DD (rosin-treated calcium carbonate) (manufactured by Nisseki Kogyo Kasei Co., Ltd.) 40 parts Curbrex #80 (manufactured by Shionogi Co., Ltd.) 5 parts sulfurized linseed oil 20 parts linseed oil 00 varnish 10 parts Phthylhydroxyanisole (BHA) 20% spindle oil solution 5 parts Spindle oil 10 parts 100 parts Using this ink, check paper (manufactured by Abekawa Paper Industries, plain MICR) was printed on a Heidel KORD offset printing machine.
Printed on paper (106 g/m ² ).

This printed matter could be easily erased using a commercially available ink eraser (manufactured by Lloyd Sangyo Co., Ltd.) and a commercially available eraser (manufactured by Tombow Pencil Co., Ltd.).

Example 2 Letterpress and lithographic sheet-fed printing inks having the following composition were kneaded using three rolls.

950 Bright Green LB (manufactured by Daido Kasei Co., Ltd.) 10 parts White Glossy DD (manufactured by Nisseki Kogyo Co., Ltd.) 30 parts Alumina White 10 parts Erosil R972 (manufactured by Nippon Aerosil Co., Ltd.) 2 parts Linseed oil No. 3 varnish 43 parts Phthyl hydroxyl toluene (BHT) ) 20% spindle oil solution 5 parts 100 parts Printed on check paper using a Hytel KORD offset printing machine in the same manner as in Example 1. This printed material could be easily erased using a commercially available ink eraser or eraser even after one month had passed after printing.

Example 3 In the formulation of Examples 1 and 2, lake pigment was added to 700%
Ink was prepared by replacing Rose Lake (Nippon Pigment), Alkaline Blue Toner 210 and 910 (Sco Morimura), and ZA278 Violet Lake (Dainichiseika), and the ink was erased and printed in the same manner as in Examples 1 and 2. It could be easily erased with an eraser.

Example 4 Transparent Yellow R Conc (manufactured by Daido Kasei Co., Ltd.) 25 parts Neolite SA-100 (manufactured by Takehara Chemical Co., Ltd.) 30 parts Erosil #200 (manufactured by Nippon Aerosil Co., Ltd.) 2 parts Sulfurized linseed oil No. 3 varnish 10 parts Linseed oil No. 3 Varnish 20 parts Dehydrated castor oil 10 parts Methylhydroquinone 25% solution (in isopropanol) 3 parts 100 parts A yellow ink was prepared using the above formulation using a triple roll. Hydel as in Examples 1, 2, and 3
Printed on high-quality paper using a KORD printing press. This printed matter could also be easily erased using a commercially available ink eraser and eraser.

Example 5 An offset rotary printing ink for business forms was prepared using the following formulation.

950 Bright Green LB (manufactured by Daido Kasei Co., Ltd.) 12 parts Hakuenka 0 (calcium carbonate) (manufactured by Nisseki Kogyo Co., Ltd.)
30 parts Espen (manufactured by Toyojun Yoko Co., Ltd.) 2 parts Erosil #200 (manufactured by Nippon Aerosil Co., Ltd.) 1 part Linseed oil No. 3 hard mouth varnish 25 parts Refined castor oil 10 parts Paulownia No. 4 varnish 4 parts BHT 20% solution (in spindle oil) 6 parts Spindle oil 10 parts 100 parts The above ink was printed on check paper using an offset rotary printing machine. Even after one month had passed after printing, the printed matter could be easily erased using a commercially available ink eraser and eraser.

Example 6 950 Bright Green LB in Example 5
700 Rose Lake (manufactured by Nippon Pigment Co., Ltd.) or Alkaline Flu Toner 910 (manufactured by Morimura Sco Co., Ltd.)
By replacing the ink with ZA278 Violet Lake (manufactured by Dainichiseika Kaisha, Ltd.), rose, blue, and purple inks for Offline BF were created, respectively. Prints made with each ink could be easily erased using a commercially available ink eraser and eraser.

Example 7 Sumikablint Blue GNO (manufactured by Sumitomo Chemical Co., Ltd.)
10 parts Transparent Yellow R Conch (manufactured by Daido Kasei Co., Ltd.) 13 parts White Glossy DD 20 parts Precipitated barium sulfate 12 parts Linseed oil No. 3 hard varnish 20 parts Sunflower oil 17 parts Tridecyl alcohol 3 parts Intermediate total 95 parts To the above combination After kneading with three rolls, the following ingredients were sequentially mixed with a dissolver and added.

20% BHT solution (in spindle oil) 3 parts Emangel 120 (Kao Atlas Co., Ltd.) 0.1 part Tap water 2 parts Total 100.1 parts Printed matter printed with this ink on high-quality paper, medium-quality paper, and corrugated paper using a Heidel KORD printing machine The green color changed to blue using a commercially available ink eraser. This is because Transparent Yellow has faded and only the Sumika Print Blue tone remains. Next, this printed matter was easily erased by rubbing it with a commercially available eraser.

Example 8 ○B Sumikaprint Blue GNO (manufactured by Sumitomo Chemical Co., Ltd.) in the ink formulation of Example 7 was added to Briant Carmine.
By replacing it with 6B1480 (manufactured by Dainichiseika Co., Ltd.), the color change due to ink erasure changes from red to red. Similarly, in ○Ro Example 7, Transparent Yellow R Conk (manufactured by Daido Kasei Co., Ltd.) was replaced with 700 Rose Lake (Japanese). Pigment Co., Ltd.), the color changed from purple to blue when the ink was erased. Moreover, the printed matter of each ink of ○, ○, and ○ could be easily erased with a commercially available eraser.

Example 9 Printing inks for letterpress and lithographic sheets were prepared using a shot mill using the following formulation.

950 Bright Green LB (manufactured by Daido Kasei Co., Ltd.) 10 parts White Glossy DD (manufactured by Nisseki Kogyo Co., Ltd.) 40 parts Erosil #200 (Nippon Aerosil) 3 parts Arakito 5001 (manufactured by Arakawa Chemical Co., Ltd.) 10 parts Linseed oil No. 3 varnish 20 parts BHT20 % solution (in spindle oil) 7 parts 590 solvent (manufactured by Nippon Oil Co., Ltd.) 10 parts 100 parts Prints printed on check paper using a Heidel KORD printing machine using this ink can be easily erased with a commercially available ink eraser and eraser. was completed.

Claims (1)

[Scope of Claims] 1. A penetrating drying ink composition comprising 30 to 60% by weight of a pigment, 0.5 to 3.0% by weight of an antioxidant, and a vehicle mainly composed of vegetable oil. 2. The ink composition according to item 1 above, further containing 0.1 to 5.0% by weight of water.