JPS60229785A - Wet paper printing - Google Patents

Abstract

PURPOSE:To enable the printing of a clear mark without peeling of paper by printing a graphic employing an ink containing an additive for prevention of paper peeling in the printing of a cutting position mark on a wet long rolled paper watermarked at the fixed position. CONSTITUTION:A cutting mark is printed on a bond paper or the like as wet paper at the fixed position with respect to the watermark in the paper making process. To produce the ink herein used, a hardened rosin resin is arranged in a solvent of butyl triglycol at the ratio of 1:1 and the mixture is heated upto 200 deg.C to melt the resin to obtain a vehicle with the viscosity of about 20 poise. Then, the vehicle and a black pigment of a coloring agent comprising carbon black are kneaded at the 20% density of the pigment with three roll mills, all of insufficient components are added thereto to meet the requirements of: 70pts. in the solvent, 20pts. in the resin, 3pts. as antipeeling additive in the dioctyl phthalate and 7pts. in the coloring agent and the mixture is stirred at a high speed. The use of the ink enables the printing of a cutting mark very clearly on the wet paper employing a letterpress system without causing any peeling thereby improving the cutting accuracy.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a wet paper paper printing method for clearly printing figures on wet paper paper containing abundant moisture immediately after forming a paper layer in a papermaking process.

Long-rolled paper that is punched in a fixed position, such as securities paper, needs a butterfly or a mark that indicates the cutting position when automatically cutting sheets. This mark must be created while the wet paper is in the papermaking process to avoid the effects of paper expansion and contraction in the drying section.

Previously, a register hole with a diameter of approximately 2 m was inserted in the middle of the papermaking process, but in order to further improve cutting accuracy, a mark with a clearer shape than the hole was placed at a fixed position relative to the large pattern on the wet paper during the papermaking process. He invented a letterpress printing method.

There is no practical example of printing on wet paper, and in this case, the most difficult problem that hinders this is the occurrence of paper peeling. In other words, when the ink on the plate comes into contact with a wet paper that has a paper layer but does not have a sufficient fiber bond of 1, the fibers of the wet paper are peeled off onto the plate by the viscosity of the ink, causing the ink to adhere to the wet paper. The paper fibers will stick to the plate side more often. This tendency increases as the stamp progresses even if the viscosity of the ink is fairly low, so inks such as those used in conventional letterpress, lithographic, and intaglio printing cannot be used. 1
However, even low-viscosity inks such as evaporative drying inks for gravure printing begin to evaporate and permeate when the printing plate contacts the paper, resulting in increased viscosity and paper peeling. Therefore, even when this problem is taken up, it is clear that considerable efforts are required in terms of ink composition.

The second problem is the transferability of the ink. Unlike dry paper, the wet paper layer, which is composed of a considerable amount of water and fibers, has poor ink absorption properties, so it forms an even ink film on its surface. It is extremely difficult to put it on.

A third problem is ink drying. After printing, the ink dries within a short time when the wet paper enters the drying section, and if the ink drying film does not have heat resistance, the ink will adhere to the surface of the blanket or drying tube, causing damage to the subsequent paper. contaminate.

The results of trials using various known inks for wet paper printing are as follows, and none of them could be put to practical use.

General oxidative polymerization drying type inks that use oil-based vehicles are not suitable at all because their viscosity causes paper peeling, and the repulsion of water and oil makes it difficult for wet paper ink to transfer, and drying is too slow. .

Penetration-drying inks for office use (for Stangs and fountain pens) dry extremely slowly and have poor heat resistance, making them unsuitable.

Evaporative drying inks that combine low boiling point solvents with resins and colorants transfer onto wet paper, but commercially available oil-based and water-based felt paper inks dry slowly and lack heat resistance for this purpose. Furthermore, evaporative drying inks using low-boiling point solvents such as acetone, benzene, and ethyl alcohol dry quickly, but they also tend to peel paper and are too volatile, making the ink unstable. Printing was difficult due to the lack of

Steam ink is used for printing on corrugated boards, etc., and is generally made by dissolving water-insoluble, highly oxidized rosin-modified maleic acid resin in glycols such as diethylene glycol, which are compatible with water, and releasing water vapor after printing. This method dries the ink in a short time by spraying it on the printed material to dilute the water-compatible solvent with water and precipitating the resin component. In wet paper printing using this method,
There was no need to spray water vapor after printing, and the amount of solvent was diffused into the water at the same time as printing, and there was a tendency for water-insoluble resin to precipitate on the paper and dry the ink. However, because the ink starts drying the moment it comes into contact with the paper, the paper peeling tendency was the most severe among the inks tested, and the ink transferability was insufficient, making it unusable as it was.

Therefore, in this invention, a vehicle that combines a glycol solvent and resin, whose drying mechanism is relatively suitable for wet paper printing, is used as an ink component, and the amount of solvent is significantly larger than that of general ink as part of the prevention of paper peeling. The ink viscosity was extremely lowered by setting the ink to 70 to 95 inches. Furthermore, in order to uniformly transfer the ink to the wet paper paper 1-, we stopped using diethylene glycol and other glycols with high surface tension as solvents to promote the ink permeability into the wet paper paper. We decided to mainly use glycol ethers with a small .

However, it is acceptable to partially mix and use glycol in order to adjust the drying speed of the ink. or,
It is also possible to add a portion of other water-soluble solvents or even water-insoluble solvents within a range that does not prevent the resin from precipitating on contact with water.

The main solvent, glycol ether, has a boiling point of 17
For example, butyl selonol, methyl-, ethyl-, propyl-, butyl-calhitol, and also methyl-, ethyl-, propyl-, butyl-triglycol can be used at a temperature of 0° C. or higher. Further, as the glycols, any of ethylene glycol and propylene glycol having different molecular weights from ethylene glycol to high molecular weight polyethylene glycol can be mixed with glycol ethyl. Other water-soluble solvents such as monofatty acid esters of glycols, mono- or di-ethers of glycols,
Ester, aliphatic, and aromatic solvents that are partially soluble in water or insoluble in water can also be mixed and used.

The resin used is one that is soluble in the above-mentioned glycol ethers alone or in a mixed solvent, but if the resin is easily dissolved, the precipitation rate of the resin when the ink comes into contact with water is slow, and the drying rate of the ink is insufficient. Therefore, it is necessary to select a resin depending on the solvent used. Resins suitable for this purpose include rosin-modified phenolic resin (for example, Tamanol 350 manufactured by Arayo Chemical Industries), alkylphenol resin (Hitanol 1133 manufactured by Hitachi Chemical Co., Ltd.), kinren resin, coumaron resin, ester resin (Pensel KK, manufactured by Arayo Chemical Industry Co., Ltd.), Bencel A
), ethyl cellulose, hardened rosin (Lime Resin I63, Lime Resin A23C manufactured by Arayo Chemical Co., Ltd.), styrene-maleic acid copolymer resin (Oki/Lac 5H-101 manufactured by Nippon Shokubai Chemical Co., Ltd.), acrylic resin (Seiko Chemical Co., Ltd. Membrane...
Iros AW-36), cellulose acetate butyrate, butyral resin (Sekisui Chemical Eslenoku BL-1, Eslenoku BL
-2), Logi/modified Malay/acid resin with an acid value of 200 or less (Marquid resin manufactured by Arayo Kagaku Kogyo Co., Ltd.), and the like. High acid value (approximately 300
) was also effective in terms of drying speed when a large amount of diethylene glycol was mixed in the solvent.

An essential requirement of the present invention is the use of additives. Additives contribute to various effects, albeit in small amounts. That is, the bonding force between the resins in the vehicle or between the resin and the solvent is strengthened, preventing ink from forming into an emulsion due to moisture contamination, suppressing ink thickening during printing, and reducing paper peeling. Also, uniform transfer of ink,
It is also effective in strengthening the ink film and accelerating drying. Materials useful as additives include oleic acid, dehydrated castor oil, fatty acids, 2-ethylhexyl alcohol, castor oil,
Examples include turpentine oil, dibutyl phthalate, dioctyl phthalate, tri-n-butyl phosphate, and low molecular weight hydroxypropyl cellulose.

The colorant mainly used was Raven 1035 (carbon black), but the ink focused on preventing paper peeling.
Since the amount of vehicle was increased considerably, the pigment concentration had to be kept low. Naturally, pigments and dyes of other colors may be used as required.

Since the viscosity of the ink used is low, we investigated the printing mechanism to ensure that it adheres uniformly to the plate surface. That is,
In order to improve the printing effect on wet paper, the surface of the roller was coated with a liquid-retaining material such as a damping sleeve (manufactured by 3M Company) that has the function of absorbing and retaining liquid materials, so that ink could adhere to the surface of the letterpress plate. As a result, the amount of ink deposited on the plate surface was constant, resulting in uniform printed figures and improved color density.

By the above method, it was possible to clearly print figures for cutting marks on wet paper.

Hereinafter, the composition of the wet paper printing ink will be explained in more detail with reference to Examples.

(The parts in each example are parts by weight.) Example 1 Solvent Butyl triglycol 70 parts Resin Curing logic/(Lime Resin A 3 made by Arayo Kagaku Kogyo 20 parts) Additive Dioctyl phthalate 3 parts Colorant Carbon black (Colon, 7 parts, U-Ben 1035 manufactured by Beer Carbon) The kneading process involves first mixing the above components of solvent and resin in a 1:1 ratio, heating to 200°C to dissolve the resin, and reduce the viscosity to approximately 20 poise. Obtain a vehicle at (30°C).

Next, this vehicle and the black pigment as a colorant are kneaded in a three-roll mill to a pigment concentration of 20%, and this is used as the base ink. Add the vehicle, solvent, and additives that are insufficient in the composition, and mix uniformly with a high-speed stirrer. It was made into a practical ink.

Using this ink composition, cutting marks could be printed extremely clearly on wet paper by letterpress printing.

Example 2 Solvent Methyl triglycol 92 parts Resin Butyral resin (Eslenoku BL-2 manufactured by Tanesui Kagaku, 5 parts) Additive 2-ethylhexyl alcohol 2 parts Colorant Oil dye (Oil Bruna 630 manufactured by Orient Chemical 1 part) ) Components other than the above-mentioned colorants were blended, heated and dissolved at 120°C, cooled in a cabinet at 80°C, and then the colorant was added, stirred and dissolved to obtain a practical ink.

Using this ink composition, printing similar to that in Example 1 could be performed.

Example 3 Solvent Methyl triglycol 42 parts Diethylene glycol 42 parts Resin Rosin-modified maleic acid resin 10 parts (Marquido-ya 33 manufactured by Aurayo Chemical Industry Co., Ltd.) Additives Oleic acid 1 part Colorant Carbon black (manufactured by Mitsubishi Kagaku Seikogyo Co., Ltd. 5 parts) Carbon black MA-100) The above components diethylene glycol and resin are mixed in a 1:1 ratio and heated to 200°C to dissolve the resin to obtain a vehicle with a viscosity of about 40 voids (30°C).

This vehicle and black pigment as a coloring agent are kneaded in a three-roll mill to a pigment concentration of 20%, and this is used as a base ink, and the vehicle, solvent, and additives that are insufficient in the composition are added and mixed uniformly with a high-speed stirrer to create a practical ink. And so.

Using this ink composition, printing similar to that in Example 1 could be performed.

Claims (2)

[Claims] (1) Wet paper with a boiling point of 170°C or higher is used for wet paper containing 60 to 75% moisture, where the fibers forming the paper layer are not fully bonded, such as wet paper immediately after press rolls on a paper machine. Water-compatible solvent mainly composed of glycol ether 70~
95%, 3-25% resin soluble in this solvent and insoluble in water,
A wet paper printing method characterized by printing figures using an ink containing as components 0.5 to 10% of a coloring agent and 0.5 to 5% of an additive for preventing paper peeling. (2) In the above-mentioned printing, the ink coating whose surface is coated with a liquid-retaining material is characterized in that a roller is held by a printing mechanism VC to uniformly transfer the ink on the plate surface 1 to perform letterpress printing. A wet paper printing method according to claim 1.