JPH06171255A - Raw paper for thermal screen printing and production thereof - Google Patents

Abstract

PURPOSE:To obtain raw paper for thermal screen printing excellent in film perforation properties and printing durability by a manufacturing method easy to control. CONSTITUTION:In raw paper for thermal screen printing consisting of a thermoplastic resin film and a porous support, as the support, a screen having a sheath/ core structure the sheath componet of which constitutes the whole or a part of a fiber constituted of a component having the compatibility with the film is used as a support and the screen is bonded to the film through the sheath component. The sheath/core structure consisting of low and high m.p. components is provided to the thermoplastic resin film. Further, the screen wherein the sheath component wholly or partially has the fiber having the compatibility with the film is thermally bonded under pressure at temp. lower than the m.p. of the film.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat-sensitive stencil printing base paper and a method for producing the same, more specifically a thermal head,
The present invention relates to a heat-sensitive stencil printing base paper excellent in heat-sensitive piercing properties such as a xenon plate-making method and a flash valve method, and a method for producing the same.

[0002]

2. Description of the Related Art A conventional heat-sensitive stencil printing base paper comprises a thermoplastic resin film such as a polyester film and a porous support adhered to one side of the film with an adhesive. The plate is made by bringing a thermal head into contact with the sheet and heat-melting the film by the heat to form an opening corresponding to the image portion of the original.

However, in such a base paper, an adhesive layer for bonding the thermoplastic resin film and the porous support is formed between the thermoplastic resin film and the porous support.
There is a problem that the perforating property of the film is apt to be impaired by the heat of the thermal head, and the organic solvent contained in the ink dissolves the adhesive layer during printing, thereby lowering the printing durability of the base paper. Further, in the production of the above-mentioned base paper, when the coating amount of the adhesive is too large, the voids of the porous support are filled with the adhesive layer, and the perforation sensitivity of the film is lowered to lower the plate making performance, and the ink passage. On the other hand, when the coating amount of the adhesive is too small, there is a problem that the adhesive strength is low, the printing durability is deteriorated, and the production process is difficult to control.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems of the prior art and to provide a thermal stencil printing excellent in film perforation and printing durability by a thermal head, a xenon plate making system, a flash valve system, etc. An object of the present invention is to provide a method for producing a base paper for heat-sensitive stencil printing that allows easy control of the base paper and the manufacturing process.

[0005]

The first invention of the present application is a heat-sensitive stencil printing base paper comprising a thermoplastic resin film and a porous support, wherein the porous support has a sheath-core structure and a sheath component thereof. Using a screen having in all or part of the fibers composed of a component having an affinity with the thermoplastic resin film, the screen is joined to the thermoplastic resin film through a sheath component, It is a heat-sensitive stencil printing base paper.

A second invention of the present application is that a thermoplastic resin film has a sheath-core structure composed of a low melting point component and a high melting point component,
A screen having all or some of the fibers whose sheath component has affinity with the thermoplastic resin film is thermocompression bonded at a temperature not lower than the softening point of the sheath component and lower than the melting point of the thermoplastic resin film. It is a method for producing a heat-sensitive stencil printing base paper, which is characterized in that they are stuck together.

In the present invention, the fiber constituting the screen acting as a porous support has a sheath-core structure, and the sheath component is a component having an affinity with the thermoplastic resin film, and the screen and the thermoplastic resin are Since the film and the screen are directly joined through the sheath component by line and point contact, there is no adhesive layer between the film and the screen, and therefore the film surface of the laminated base paper is smooth. In addition to improving the properties, the adhesion with the thermal head during plate making is improved, and the heat transfer efficiency is improved, and the plate making sensitivity can be greatly improved. Further, since the surface of the base paper is smooth, the pressure applied per unit area during printing becomes uniform, the printing becomes uniform, and an image more faithful to the original can be obtained.

As the thermoplastic resin film used in the present invention, a film of polyester, polyvinyl chloride, polypropylene or the like is usually used, and the thickness thereof is from 0.5 to 0.5 from the viewpoint of thermal piercing property and film strength. 8 μm.

The screen used in the present invention is composed of a cloth or a web having a composite fiber having a sheath-core structure in all or part thereof, and the sheath component is composed of a component having an affinity with the thermoplastic resin film. The component having an affinity with the thermoplastic resin film refers to a component which has a sufficient bonding force with the film by an alternative means such as thermocompression bonding or light irradiation and is not easily peeled off. Such a component may be the same as the thermoplastic resin film.

When the above screen is joined to the thermoplastic resin film by heating, the melting point of the sheath component is lower than that of the thermoplastic resin film and the core component of the composite fiber. For example, when a polyethylene terephthalate film is used as the thermoplastic resin film, as a sheath component, a copolymer polyester having a lower melting point than that, for example, polyethylene terephthalate is copolymerized with other monomers or reaction components such as polyethylene glycol during polymerization. Those are preferably used. Examples of other monomers or reaction components include dicarboxylic acids such as isophthalic acid, adipic acid and dimer acid, low molecular weight glycols such as diethylene glycol and butanediol, and polyalkylene glycols such as polyethylene glycol and polytetramethylene glycol. .

The core component of the composite fiber is not particularly limited as long as it does not melt by thermocompression bonding when the screen and the thermoplastic resin film are bonded together. For example, polyester, particularly polyethylene terephthalate is preferably used in terms of price and the like. To be The ratio of the sheath component used is such that the sheath component of the multi-layer fiber is softened or heat-melted by thermocompression bonding and adheres to the thermoplastic resin film, but the adhesive force at that time is sufficient.
Further, the amount may be such that the holes of the screen are not crushed by the deformation due to softening or the hot melt. Usually, the cross-sectional area ratio of the sheath component / core component is preferably in the range of 5/95 to 50/50. The composite fiber cross-sectional shape may be circular or modified. Moreover, the cross-sectional shape and the number of cores are not always similar to each other.
The book does not have to be a book, and can be appropriately selected and determined as needed.

The composite fiber is obtained by a usual melt spinning method using a known sheath-core composite spinning nozzle, and the composite fiber (filament) is used in whole or in part and woven by a known method. The screen used in the present invention can be obtained. The screen may be composed of only the composite fiber, but the composite fiber may be used only in a part of the fiber, for example, in the warp yarn or the weft yarn. You may use it for every book etc. As the fiber used in addition to the composite fiber, for example, a normal fiber made of the above-mentioned high melting point component polyester can be used. The mesh size of the screen is preferably in the range of 70 mesh to 400 mesh, and the thickness thereof is preferably in the range of 40 μm to 200 μm, from the viewpoint of ink permeability and imageability.

The base paper for heat-sensitive stencil printing of the present invention is manufactured by thermocompressing and bonding a thermoplastic resin film and a screen as a porous support by means of a nip roll or the like. The temperature and pressure of thermocompression bonding are
Depending on the material of the thermoplastic resin film or screen, as described above, it is determined that the composite fiber is heated to a temperature above the softening point of the low melting point component and lower than the melting point of the high melting point component and the thermoplastic resin film. . For example, in the case of a heat-sensitive stencil printing base paper in which a polyester film is attached to a cloth composed of polyester composite yarn using copolymerized polyester as a low melting point component, a nip pressure of 1 is applied between a metal roll heated to 120 ° C. and a silicone rubber roll. ．
It can be thermocompression bonded at 8 kg / cm ² .

[0014]

EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited thereto. Example 1 A screen made of a polyester fiber having a multi-filament sheath-core structure (trade name: TP-70, manufactured by Nippon Tokushu Kyoho Co., Ltd.)
0, 70 mesh, thickness 110 μm,) and thickness 2 μm
The polyethylene terephthalate film in Example 1 was superposed and passed through a metal roll heated to 120 ° C. and a silicone rubber roll at a nip pressure of 1.8 kg / cm ² to bond the screen and the film to produce a heat-sensitive stencil printing base paper. The surface of the fiber constituting the screen was uniformly adhered to the film by heat fusion. When dimethyl silicone oil was applied to the film surface of this base paper and mounted on an integrated plate-making printing machine (RC-115) manufactured by Riso Kagaku Kogyo Co., Ltd., and plate-making printing was performed, a good printed image could be obtained. .

Example 2 Polyester composite fiber (monofilament) having a sheath-core structure
A screen (manufactured by NBC Industry Co., Ltd., opening 200 mesh, thickness 75 μm) was overlaid on a polyethylene terephthalate film having a thickness of 2 μm, and the nip pressure between the metal roll heated to 120 ° C. and the silicone rubber roll was 1.8 kg / cm. ^After passing through ² and pasting the screen and the film together, a heat sensitive stencil sheet was prepared. Dimethyl silicone oil was applied to the film surface of this base paper, and an integrated plate-making printing machine (RC-11 manufactured by Riso Kagaku Kogyo Co., Ltd.) was applied.
When it was mounted on the plate 5) and plate-making printing was carried out, a good printed image could be obtained.

Example 3 Polyester composite fiber (monofilament) having a sheath-core structure obtained by composite spinning of a low melting point component (copolymerized polyester) and a high melting point component (homopolyester) at a ratio of 10/90 (weight ratio). Screens of 135 mesh, 200 mesh and 420 mesh (thickness of 90,
70, 60 μm) was produced. These screens and a polyethylene terephthalate film having a thickness of 2 μm were superposed, and passed between a metal roll heated to 120 ° C. and a silicone rubber roll at a nip pressure of 1.8 kg / cm ² to bond the screen and the film to each other to obtain a heat-sensitive stencil. Each of the printing base papers was produced. When dimethyl silicone oil was applied to the film surface of these base papers and mounted on an integrated plate-making printing machine (RC-115) manufactured by Riso Kagaku Kogyo Co., Ltd., plate-making printing was performed, and good printed images were obtained. It was

Comparative Example 1 A polyethylene fiber screen (NB having a softening point of 105 ° C.)
C Industry Co., Ltd., nip strong mesh, 150 mesh) and a 2 μm polyethylene terephthalate film were superposed and thermocompression-bonded in the same manner as in Example 1. However, the fibers constituting the screen were softened to form a film, which was completely ink. Was unable to pass.

Comparative Example 2 Polypropylene fiber screen (N
15 nip strong mesh, manufactured by BC Kogyo Co., Ltd.) and a 2 μm polyethylene terephthalate film are overlapped, and 15
When the film was passed between a metal roll heated to 0 ° C. and a silicone rubber roll in the same manner as in Example 1, the fibers constituting the screen were deformed, the bonding strength between the screen and the film was extremely weak, and the film was slightly picked. Peeled off.

Comparative Example 3 Polyester screen (trade name TN manufactured by NBC Industries Co., Ltd.)
0.200S) and a polyethylene-based multilayer film (trade name: 212.T, manufactured by Dainippon Ink and Chemicals, Inc.) and heated to 100 ° C. with a nip pressure of 1.8 kg / cm ² between a metal roll and a silicone rubber roll. Let it pass. Although the surface layer of the film was softened and a good laminate could be obtained, when dimethyl silicone was applied to the film surface and plate-making printing was carried out in the same manner as in Example 1, the film was not perforated at all, I couldn't get the image.

[0020]

According to the first invention of the present application, since the screen and the thermoplastic resin film can be directly bonded to each other without forming an adhesive layer, excellent film piercing property and printing durability can be obtained. To be According to the second invention of the present application, since the step of forming the adhesive layer between the screen and the thermoplastic resin film is unnecessary, management of the manufacturing process becomes easy.

Claims (2)

[Claims] 1. A heat-sensitive stencil printing base paper comprising a thermoplastic resin film and a porous support, wherein the porous support has a sheath-core structure and the sheath component has affinity with the thermoplastic resin film. A base paper for heat-sensitive stencil printing, characterized in that a screen having fibers composed of components in all or a part thereof is used, and the screen is bonded to the thermoplastic resin film via a sheath component. 2. A screen in which a thermoplastic resin film has a sheath-core structure composed of a low-melting point component and a high-melting point component, and the sheath component has all or part of fibers having an affinity with the thermoplastic resin film. Are bonded by thermocompression bonding at a temperature not lower than the softening point of the sheath component and lower than the melting point of the thermoplastic resin film.