JPH0252638B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a heat-sensitive stencil paper. More specifically, by superimposing the document with a document containing characters, figures, etc. and irradiating it with infrared rays,
The present invention relates to a heat-sensitive stencil paper in which a portion corresponding to a figure absorbs infrared rays, is melted by the generated heat, and is perforated to form a stencil.

Conventionally, heat-sensitive stencil paper has a structure in which a vinyl chloride resin film such as polyvinyl chloride is laminated with an adhesive to a porous support made from fibers such as paper mulberry, Japanese mulberry, Manila hemp, vinylon, or polyester. This method is known (for example, Japanese Patent Publication No. 7623/1973, Japanese Patent Publication No. 17336/1972, and Japanese Patent Publication No. 23713/1973). The thinner the porous support used in these heat-sensitive stencil papers is, the more advantageous it is in terms of perforation and printability.
g/m ² is used. However, such a thin porous support is very sensitively affected by humidity; for example, when humidity is high, the strength decreases and elongation increases, while when humidity is low, strength is high but shrinkage occurs. On the other hand, the vinyl chloride resin film to be laminated is easily affected by temperature, but is less affected by humidity. In addition, vinyl chloride resin films are generally used that contain a large amount of plasticizer, but when such films are used, they are bonded to porous supports using adhesives, and after a long period of time the film deteriorates. A problem arises in that the plasticizer therein oozes out and migrates into the highly water-absorbing porous support or into the adhesive. The plasticizer oozed out in this manner reduces the adhesive strength between the film and the porous support, thereby degrading the quality of the heat-sensitive stencil paper.

In this way, the porous support and the vinyl chloride resin film are affected to different degrees by external conditions such as humidity and temperature, and there is also the problem that adhesive strength decreases due to plasticity bleeding in the film. It was hot.

Furthermore, although vinyl chloride resin film is usually thin and moderately stretched,
It has been extremely difficult to adjust the thickness and stretching ratio of these films for heat-sensitive stencil paper during film production. In order to solve this problem, for example, it is possible to select the type of adhesive used for lamination (Japanese Patent Publication No. 47-1187), or to impregnate the entire porous support with a synthetic resin (Japanese Patent Publication No. 55-47997). ) has been proposed, but nothing satisfactory has yet been achieved. For example, when the entire porous support is impregnated with synthetic resin, the influence of the plasticizer that bleeds and the influence of humidity are reduced, but because the amount of the synthetic resin that is the adhesive is large, the porous support As the porosity decreases and the permeability of printing ink increases, the print clarity actually decreases. Furthermore, when using a specific adhesive, although the plasticizer in the film does not migrate into the adhesive, it still migrates into the porous support, resulting in poor lamination and adhesive strength stability. Furthermore, since the method is limited to a specific adhesive, there are problems in that it is not possible to select an adhesive suitable for increasing adhesive strength, improving perforation resolution, etc.

However, as a result of intensive research to improve the above-mentioned drawbacks of conventional heat-sensitive stencil paper, the present inventors found that
The present inventors have discovered that by interposing an acrylic resin layer between the vinyl chloride resin film and the adhesive layer, it is possible to obtain a heat-sensitive stencil paper that is stable over time and provides clear printed matter, and has developed the present invention. It was about to be completed.

That is, the present invention uses a vinyl chloride resin film with a thickness of 25 μm or less, and a porous support made of natural fiber or synthetic fiber with a basis weight of 6 to 14 g/m ² and a thickness of 20 to 60 μm. using your body,
One side of the vinyl chloride resin film has a thickness of
Provided is a heat-sensitive stencil paper characterized in that an acrylic resin layer of 10 μm or less is coated, and a porous support is bonded to the surface of the acrylic resin layer with a suitable adhesive.

In the present invention, by interposing the acrylic resin layer between the vinyl chloride resin film and the adhesive layer, the following excellent effects can be achieved.

Since migration due to leaching of the plasticizer in the vinyl chloride resin film is prevented, the bonding strength does not decrease over time and is stable.

The types of adhesives that can be used are not particularly limited, and can be selected from a wide range of adhesives. Therefore, it is possible to use an adhesive that exhibits high adhesive strength with a small amount of use, and a base paper with high bonding strength can be obtained. Furthermore, the type of adhesive can be selected so as to obtain a base paper with better perforation resolution.

The thickness and shrinkage rate of the vinyl chloride resin film can be adjusted by adjusting the thickness of the acrylic resin layer, which is extremely advantageous in manufacturing.

The vinyl chloride resin film used in the present invention has a thickness of 25 microns or less, preferably 5 to 20 microns. If the thickness exceeds the above range, the perforation property by infrared rays will be poor and it will be difficult to obtain a stencil that is faithful to the original. As the vinyl chloride resin film, a stretched film, especially a biaxially stretched film, is used, with a stretching ratio of 100 in the vertical direction and in the horizontal direction.
-300%, particularly preferably in the range of 150-300%. The vinyl chloride resin film may be a vinyl chloride polymer film mainly composed of vinyl chloride, but polyvinyl chloride film is usually used.

The porous support used in the present invention has a fineness of 3
Synthetic fibers such as polyester fibers, vinylon fibers, and nylon fibers, or natural fibers such as manila hemp, paper mulberry, myrmata, and pulp, singly or in combination, are used.
The porous support has a basis weight of 6 to 14 g/m ² , especially 8 to 14 g/m ² , and a thickness of 20 to 60 μ, especially 30 to 30 μm.
50μ is preferable.

In the present invention, the acrylic resin used to form the acrylic resin layer includes homopolymers of acrylic esters and methacrylic esters, copolymers thereof, and vinyl chloride, vinyl acetate, etc. mainly composed of the above monomers. This concept includes any copolymer with other monomers. The acrylic resin may be used alone, or may be used in combination with a small amount of other appropriate resins, such as cellulose resins, epoxy resins, vinyl chloride resins, and vinyl acetate resins. The other resin is preferably one that can be dissolved in a solvent that does not dissolve or swell the vinyl chloride resin film, such as a solvent mainly composed of alcohol solvents.

The acrylic resin layer has a thickness of 10 microns or less, preferably 1 to 5 microns. If the thickness exceeds 10 μm, the perforation performance by infrared irradiation will be poor, making it impossible to obtain a stencil that is faithful to the manuscript. Moreover, if it is less than 1μ, pinholes will occur in the resin layer during the manufacturing process, making it impossible to prevent the plasticizer from bleeding in the vinyl chloride resin film, reducing the effect of providing the resin layer.

The adhesive used in the present invention is not particularly limited, but examples thereof include vinyl acetate, polyvinyl alcohol, polyamide, polyester, and rubber adhesives, including those that dissolve in solvents that do not dissolve the acrylic resin layer. Preferably used.

In the heat-sensitive stencil paper of the present invention, a solvent solution of the acrylic resin is applied to one side of the vinyl chloride resin film so that the thickness after drying is within the above range, and then the adhesive is applied to the acrylic resin. It is obtained by coating the surface of the layer so that the coating amount after drying is 0.5 to 2.5 g/m ² , and then superimposing and adhering the porous support and drying by heating.

In addition, if the thickness of the vinyl chloride resin film used is 10μ or less and the stretching ratio is 200% or more,
The thickness of the acrylic resin layer is slightly thicker at 2.5 to 5μ.
Conversely, the thickness of vinyl chloride resin film is 10 to 20μ.
If the stretch rate is less than 200% or more than 100%,
It is preferable that the thickness of the acrylic resin layer be a little thin, 1 to 2.5 microns. In addition to considering the type, amount, and melting point of the plasticizer in the vinyl chloride resin film, the relationship between the thickness and stretching ratio of the vinyl chloride resin film and the thickness of the acrylic resin layer should be adjusted in this way. By this, perforation performance can be further improved.

Next, the present invention will be explained with reference to Examples and Comparative Examples.

Example 1 10 parts of methacrylic acid ester resin (parts by weight, the same applies hereinafter) and isopropyl alcohol were applied to one side of a biaxially stretched polyvinyl chloride film with a thickness of 15 μm (stretching ratio of about 200% in both the vertical and horizontal directions). 80
A resin solution consisting of 10 parts of methoxymethylated polyamide resin,
Apply an adhesive solution consisting of 70 parts of methanol and 20 parts of water so that the dry coating amount is 1.0 g/ ^m2 ,
Furthermore, it is made by mixing 80 parts of polyester fiber and 20 parts of Manila hemp, with a basis weight of 9.8 g/m ² and a thickness of 35 μm.
The porous supports were layered and dried by heating to obtain a heat-sensitive stencil paper.

This heat-sensitive stencil paper was superimposed on the manuscript, and perforation was made using a RISOGRAPHAX FX7200 heat-sensitive plate-making machine manufactured by Riso Kagaku Kogyo Co., Ltd.
As a result of printing on a 420W rotary press, 3,000 extremely clear prints were produced.

Example 2 20 parts of a copolymer resin of methacrylic acid ester and acrylic acid ester and 80 parts of isopropyl alcohol were applied to one side of a biaxially stretched polyvinyl chloride film (stretching ratio is about 200% in both the vertical and horizontal directions) with a thickness of 8 μm. After heating to 40℃, apply the resin solution to a dry thickness of 3.0 μm. After heating and drying, apply an adhesive solution consisting of 20 parts of vinyl acetate-ethylene copolymer resin and 80 parts of methanol on top of the dry coating amount. ^{A porous support made of Manila hemp having a basis weight of 10.5 g/m 2 and} a thickness of 40 μm was placed thereon and dried by heating to obtain a heat-sensitive stencil paper.

This heat-sensitive stencil paper was superimposed on the manuscript, perforated using a thermal plate-making machine (Print Gotsuko) manufactured by Riso Kagaku Kogyo Co., Ltd., and printed using a color printer manufactured by Asia Genshi Co., Ltd., resulting in 100 extremely clear prints. I was able to get it.

Furthermore, when the heat-sensitive stencil paper obtained in Examples 1 and 2 was left for 90 days at 50°C and 60% RH, the polyvinyl chloride film coated with the acrylic resin layer and the porous support were separated. The adhesion strength and print clarity between the two were the same as those immediately after manufacture, with no change at all.

Comparative Example 1 A heat-sensitive stencil paper was obtained in the same manner as in Example 1, except that the same polyvinyl chloride film, adhesive, and porous support as in Example 1 were used, and the acrylic resin layer was not provided.

Using this heat-sensitive stencil paper, printing was carried out using the same heat-sensitive stencil maker and rotary printing machine as in Example 1, and the resultant printed matter was compared with that obtained in Example 1. However, after being left at 50°C and 60% RH for 90 days, the printing clarity was extremely poor, especially when the outlines of letters and figures on the manuscript were continuous. For example, in the case of characters and figures such as ○, □, country, etc., the film inside the outline falls off during printing, so the characters and figures such as ●, ■, and ■ may be completely filled in. I couldn't help it.

Comparative Example 2 A heat-sensitive stencil paper was obtained in the same manner as in Example 2, except that the same polyvinyl chloride film, adhesive, and porous support as in Example 2 were used, and the acrylic resin layer was not provided.

This heat-sensitive stencil paper was printed using the same heat-sensitive plate making machine and color printer as in Example 2, and the resulting printed matter was compared with that obtained in Example 2. As a result, the drawing lines of figures and characters were All I could get was thick prints with poor clarity. In particular, letters smaller than No. 5 type were difficult to read.

Next, after leaving the heat-sensitive stencil paper for 90 days at 50°C and 60% RH, we tried the same test as above, and found that the polyvinyl chloride film and porous support had partially peeled off. , wrinkles occurred, making it impractical.

Claims (1)

[Claims] 1. In a heat-sensitive stencil paper made by laminating a stretched vinyl chloride resin film with a thickness of 25μ or less and a porous support with an adhesive, there is a thickness between the vinyl chloride resin film and the adhesive layer. A heat-sensitive stencil paper characterized by having an acrylic resin layer of 10μ or less interposed therein.