JPS6215395A - Method for transparentizing opaque paper - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Industrial field of application This invention is a method for making envelopes, packaging materials, etc. made of opaque paper transparent by a simple method and displaying letters such as addresses on the surface of the contents. This invention relates to a method for making it possible to read and identify figures, etc. from the outside, and, as will be described later, relates to a method that solves various drawbacks of conventional methods.

(b) Prior art The paper to be made transparent as described above is usually so-called single gloss paper, bleached kraft paper, high-quality paper, etc., but in the past, rosin, wax, paraffin, polyethylene, etc. were used as the transparentizing agent. A solid polymer substance dissolved in a chlorinated solvent such as perchlorethylene or trichlorethylene is
Printing is done by letterpress or other methods under heating at 60°C to 100°C, and then heated to 300'C to 400'C by a heating method such as a gas burner direct flame type, followed by a long drying oven and It was made transparent by passing it through a cooling furnace and drying it.

However, the conventional methods described above have the following drawbacks. That is, (1) Since the main ingredients are rosin and wax, it is necessary to keep the printing unit warm during printing.

■ A large amount of thermal energy is required to melt the transparency agent component transferred to the paper by printing and then cool and solidify it.
Moreover, it requires a long drying oven and cooling oven.

■Chlorinated organic solvents were used to prevent ignition, which caused problems in terms of occupational health and pollution.

(C) Problems to be Solved by the Invention The present invention has been made in order to solve the various drawbacks of the conventional paper transparency methods as described above.

That is, in the method of making opaque paper transparent according to the present invention, since a liquid material is used as a coating material in the printing process of a transparentizing agent,
No heating is required for melting and liquefaction, printing units can be used at room temperature, and the drying process can be performed at low temperatures and with short drying equipment, thus significantly reducing the use of thermal energy. Moreover, by not using chlorinated solvents,
This was completed as a result of research in search of a method that would not cause the risk of deterioration of the working environment or the occurrence of pollution.

(d) Means for Solving the Problems In order to solve the above problems, the present inventors printed a transparentizing agent mainly composed of vegetable oil on the surface of opaque paper, and then used a transparentizing agent that penetrated into the paper. To prevent vegetable oil from leaching to the outside,
This method has been developed to form a protective film on the surface.

That is, when vegetable oil is printed on paper, it rapidly penetrates and makes the paper transparent.

However, since the oil is still in an undried state, it has no practical value, but if a protective film of oil is then printed on both the front and back sides of the oil-printed area, extremely good transparency can be achieved. A practical printed matter can be obtained.

In the above case, the vegetable oil used is generally known tung oil, linseed oil, castor oil, hydrophilic castor oil, coconut oil, soybean oil, or commercially available salad oil.

When printing with vegetable oils such as these, it is necessary to adjust the viscosity to suit the printing machine. Can be used selectively.

As a protective film for vegetable oil printed on paper, a resin is used that prevents the oil from leaching or migrating to the surface of the paper and does not reduce or increase the transparency of the paper.

For example, solvent types include chlorinated rubber, vinyl chloride, vinylidene chloride, acrylic resin, modified acrylic resin, polyamide resin, urethane resin, nitrified cotton, rosin-modified maleic resin, rosin-modified phenolic resin, styrene resin, etc., and water-based resins. Examples include rosin-modified maleic acid resin,
Examples include styrene modified resin, acrylic resin, alkaline aqueous solution of modified acrylic resin, synthetic rubber latex, vinylidene chloride latex, vinyl acetate emulsion, emulsion of acrylic and modified acrylic resin, etc., and these resins can be used singly or in combination. A protective film can be obtained. Since the clarifying agent (oil layer) and the oil layer protectant that forms the protective film are both liquid, suitable methods for printing them include the flexographic method, gravure method, and graphoff method. Therefore, as an actual printing method, a single method or a combination of these methods can be used.

The printing order of the clarifying agent and the oil layer protectant can be either done first, but as a result, after printing, the volatile content in the oil layer protectant evaporates, and the cross-sectional view is shown in Figure 1. Protect both sides of the transparency agent (oil layer) (B) that has penetrated the base paper (A) as shown in III! It is necessary to coat with (C).

Figure 2 shows an example of the printing process, and shows the surface printing unit (1
), (2), a back printing unit (3), and a hot air blower (4).

The printing unit may be a flexible type, a gravure type, or a graph-off type, or a combination thereof.

(e) Effect By printing a combination of a clarifying agent mainly composed of vegetable oil and a protective film forming agent dissolved in water or other volatile solvent, the temperature of the process can be lowered and the working time can be shortened.

(f) Examples The structure of the present invention will be specifically explained below with reference to Examples.

Example 1 Clarifying agent (A) Hydrophilic castor oil 80 parts (hereinafter weight ratio) (manufactured by Nicca Oil Co., Ltd.) Contains 100 parts of butyl acetate ester-1 viscosity 10 seconds (#4 Zanka knob) Oil layer protection Agent (B) Polyamide resin 30 parts (Kao Soap Co., Ltd. Reomidoro 500) Toluene 30 parts Ethyl acetate 20 parts Isopropyl alcohol U plate 100 parts Viscosity 12 seconds (#4 Zaan Kafubu) Pure white roll using #10 bar coater The clarifying agent (A) was applied onto paper (50 g).

Next, apply an oil layer protectant (B) to the same surface using the same bar coater.
) was applied, and then an oil layer protectant (B) was applied to the back side.

Drying was completed by blowing warm air at 60°C onto the coated surface for 4 seconds.

The coating thus obtained had excellent transparency and a good film condition.

Example 2 Clarifying agent (C) Only linseed oil (made in China) was used. Viscosity: 10 seconds (#4 Zahn cup) Oil layer protectant (D) Acrylic emulsion 70 parts (Joncryl 74J manufactured by Johnson Wax Co.) Water-soluble acrylic resin
20 parts (Jonkryl 61J manufactured by Johnson Wax Co.) Water-dispersed wax 6 parts (John Wax 26 manufactured by Johnson Wax Co.) Water
4 parts antifoaming agent
--11 dishes (manufactured by Shin-Etsu Silicon Co., Ltd. 100.2 parts silicon KM
・70) Viscosity 20 seconds (#4 Zahn cup) Using a flexographic two-color printing tester equipped with a 5 x 91 rubber solid plate (letterpress), apply the clarifying agent to the first color on pure white roll paper (50 g). (C) and oil layer protectant (D) as the second color.
After overprinting and winding up, apply oil layer protectant (D) on the opposite side.
I overprinted it.

The resulting printed matter had sufficient transparency to read the characters placed on the base.

Example 3 Clarifying agent (E) Tung oil (made in China) 80 parts Toluene - 11 dishes 100 parts Viscosity 10 seconds (#4 Zahn cup) Oil layer protectant (F) Acrylic resin 30 parts (manufactured by Fujikura Kasei Co., Ltd., Acrybase MM42B) Toluene 40 parts Ethyl acetate -m 100 parts Viscosity 12 seconds (#4 Zahnkap 7p) Each printing unit has a 5X9cI11 solid plate (depth 40μ
Using a gravure printing tester (three-color machine) equipped with a gravure plate (intaglio), apply a clarifying agent (E) to the first color, an oil layer protectant (F) to the second color, and flip the paper over pure white roll paper (50 g). After that, an oil layer protectant (F) was continuously printed as the third color.

A 1.2kw hot air blower is installed in each printing unit.
Printing was performed at a speed of 0 m/min.

The resulting printed matter had sufficient transparency to read the characters placed on the base.

(g) Effects of the Invention The method of making opaque paper transparent according to the present invention does not require heating or keeping the printing unit warm as in conventional methods, and also requires a large amount of transparentizing agent to be melted, cooled and solidified, etc. It does not require energy or lengthy drying or cooling equipment, and can be carried out at low temperatures with simple equipment.Furthermore, since it does not use chlorinated organic solvents, there are no problems in terms of occupational health, pollution, etc. This is an industrially novel invention that has many effects such as:

[Brief explanation of the drawing]

FIG. 1 is a partially enlarged sectional view of paper made transparent according to the present invention. FIG. 2 is a process diagram showing an example of the manufacturing process. In the figure A -----------
・Clearing agent (oil layer) C-----1--------
−−=−Protective film 1, 2.3−−−−−−−−−−−−
---Printing unit 4-----
−−−−−−−−−One hot air blower 5−−−−−−−−−
−−−−−−−−−・−・−Base paper (rolling)) 6−−−−
−−−−−−−−−−−−−−−−−−−・Transparent paper (
Roll) Patent applicant: Osaka Printing Ink Manufacturing Co., Ltd. No. 1
Figure 2

Claims (1)

[Claims] A transparentizing agent mainly composed of vegetable oil is printed and infiltrated on a specific side of opaque paper, and an oil layer protective agent for fixing the transparentizing agent is printed on both sides of the transparentizing agent permeation layer and dried to form an oil layer protective film. A method of making opaque paper transparent, characterized by forming.