JPH0313997B2 - - Google Patents

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a heat-sensitive stencil paper and a method for producing the same, and more specifically to a thin film of heat-set biaxially oriented synthetic resin and a porous thin paper. The present invention relates to a heat-sensitive stencil printing base paper obtained by laminating the above and the like, and a method for producing the same.

<Prior art> Conventional base papers for heat-sensitive stencil printing include those made by impregnating thin paper with a wax-like substance, and those made by laminating vinylidene chloride-vinyl chloride copolymer resin film and thin paper (Japanese Patent Publication No. 43-23713). No. 2), etc. are publicly known.

These heat-sensitive stencil printing base papers are overlaid with a document having an image area with high heat absorption and heat retention properties, and are heated by infrared rays from the base paper side.The image area becomes high temperature and wax-like substances or This method utilizes the fact that a vinyl chloride resin film melts and contracts, forming pores that allow printing ink to pass through.

However, in the base paper impregnated with the above-mentioned wax-like substance, the wax-like substance melted during infrared irradiation (hereinafter referred to as plate-making) contaminates the manuscript.
It has drawbacks such as poor resolution.

In addition, products using the above-mentioned vinyl chloride resin film can overcome the above-mentioned defects in the base paper impregnated with a wax-like substance, but it is difficult to obtain a thin and uniform thickness due to the film forming process. There are drawbacks such as uneven plate making occurring at specific locations on the base paper and the need for a large-capacity infrared ray generator during plate making.

Furthermore, products using the above-mentioned vinyl chloride resin film suffer from large heat shrinkage over time due to insufficient heat fixation during the film forming process, causing curling to occur after base paper production or immediately after plate making, making it difficult to handle during plate making and printing. It was inconvenient.

On the other hand, a stretched thermoplastic resin film and a thin paper pre-impregnated with a synthetic resin are superimposed, or after the stretched thermoplastic resin film and the thin paper are superimposed, the thin paper is impregnated with a synthetic resin liquid. A method of drying by drying is proposed (Japanese Patent Publication No. 55-47997).

Furthermore, JP-A No. 59-22796 proposes applying an adhesive paint to a polyester film, overlaying it with porous tissue paper or a mesh-like sheet in an undried state, and then drying and laminating the film. ing.

<Problems to be Solved by the Invention> The method disclosed in the above-mentioned Japanese Patent Publication No. 55-47997 uses a synthetic resin impregnated into thin paper to function as an adhesive between the thin paper and the film. The smaller the number of synthetic resins used, the better in terms of resolution and printability.

However, when the amount of adhesive is reduced in order to improve resolution and printability, the adhesive strength between the film and thin paper that make up the base paper naturally decreases, and the film and thin paper are not bonded together during base paper manufacturing. There are defects such as missing portions, or prints where the center of a circle or square, for example, is missing during plate making or printing.

It is possible to use the dry lamination method, which is a long-known technique, in order to obtain higher adhesive strength with the same amount of adhesive, but in this case, compared to the base material to which the dry lamination method has been applied,
The thin paper, which is one of the base materials that make up the base paper, is porous and has a small effective contact area with the other base material.
In other words, it cannot be an effective method because the bonding surface lacks smoothness and continuity.

Furthermore, in the method disclosed in Japanese Patent Application Publication No. 59-22796, if the amount of adhesive paint is increased, the paint will penetrate and impregnate the porous thin paper that is then stacked. On the other hand, if the amount of adhesive paint is reduced, air may be drawn into the bonding interface when the tissue paper is stacked next time.
It is not possible to absorb and eliminate slight wrinkles or sag in the film or thin paper, resulting in defects such as inability to stably produce the film or tissue paper.

On the other hand, thin paper has dense and dense areas,
In the above-mentioned prior art, in the drying process after lamination, drying progresses from the rough areas, and the adhesive paint becomes highly concentrated and concentrated in the dense areas, and then drying ends.

As a result, the dense portions of the thin paper, which originally have relatively poor heat ray transparency and ink permeability, contain more adhesive, further worsening the heat ray transparency and ink permeability.

<Means for Solving the Problems> In order to solve the above problems, the present invention provides a heat-sensitive stencil plate in which a heat-set biaxially stretched synthetic resin thin film and a porous thin paper are bonded together using an adhesive paint. The present invention proposes a heat-sensitive stencil printing base paper in which the adhesive coating is present in a gradually smaller amount from the bonding surface of the film and porous thin paper toward the outer surface of the porous thin paper.

Furthermore, when laminating the heat-set biaxially stretched synthetic resin thin film and the porous thin paper, an adhesive paint is applied to the laminating surface of the film, and the porous thin paper supplied from the other side is impregnated with a solvent. The present invention proposes a method for producing a heat-sensitive stencil printing base paper, in which the adhesive paint is gradually caused to exist slightly from the bonding surface toward the outer surface of the porous tissue paper, and then the paper is bonded and dried due to the surface tension of the solvent. .

The heat-set biaxially stretched synthetic resin thin film used in this invention is a thin film of polyethylene terephthalate, polypropylene, etc. that has been heat-set after biaxial stretching, and is at least at a temperature below the melting point and at least 50°C lower than the melting point. It is necessary to heat set after stretching at a temperature of . If the heat setting temperature is 50°C or more lower than the melting point, problems such as shrinkage during base paper production and curling during product storage will occur.

Further, the thickness varies depending on the melting point of the synthetic resin used, but in the case of polyethylene terephthalate, it is preferably 0.5μ to 5μ, more preferably 1μ to 4μ. In the case of polypropylene, the thickness is preferably 0.5 to 10μ, more preferably 1 to 8μ.

The porous thin paper used in this invention may be made of natural fibers such as Manila hemp, kozo, mitsumata, etc., synthetic fibers such as polyester, nylon, etc., or a mixture thereof, and has a basis weight of 5 to 15 g/m ² .

Adhesive paints are made by dissolving various resins such as vinyl acetate, vinyl chloride, acrylic, polyester, and nylon in an appropriate solvent and adjusting the concentration to provide the necessary adhesive strength, or the above synthetic resin emulsion. , latex, etc. can be used. In addition, if necessary, the above adhesive paint may be used.
Further, antistatic agents, antioxidants, dyes, pigments, etc. may be added to increase commercial value.

The basis weight of the adhesive paint after drying varies slightly depending on the basis weight, density, etc. of the porous thin paper used, but is preferably 0.2 g/m ³ to 4 g/m ³ , more preferably 0.5 g/m ^{3 to 2 g/m 3} . It is ³ . If the amount is less than this, the adhesive force will be poor, and under severe conditions during plate making or printing, for example, the center of a round portion may fall off, resulting in a decrease in the fidelity of the original. If the amount of adhesive paint is larger than this, the adhesive force will be excessive and the desired clear print may not be obtained, or if the amount of adhesive paint is larger than that required to achieve the same clarity, A larger amount of heat ray irradiation is required, which tends to cause trouble when peeling off after plate making.

In addition, the solvents used in this invention include ketones such as acetone and methyl isobutyl ketone, alcohols such as methanol and ethanol, esters such as ethyl acetate, aromatic solvents such as toluene, and mixed solvents thereof. water etc. can be used.

In addition, in order to improve the peelability between the base paper and the manuscript after plate making, silicone resin, metal soap, various surfactants, etc. may be applied alone or in combination to the film surface or impregnated throughout the base paper, and then dried. .

<Function> As described above, in this invention, when bonding a heat-set biaxially stretched thin synthetic resin film and porous tissue paper, an adhesive paint is applied to the bonding surface of the film and supplied from the other side. The porous tissue paper is impregnated with a solvent. Therefore, the adhesive paint applied to the film bonding surface during lamination penetrates into the interior of the porous thin paper from the film bonding surface due to the surface tension of the solvent, and its concentration increases at the film bonding surface. It exhibits a distribution that is highest and becomes thinner towards the outer surface of the porous tissue.

Therefore, although the base paper of the present invention has sufficient adhesive strength between the porous thin paper and the thin synthetic resin film, the amount of adhesive paint used therein is small, and the bonding on the porous thin paper side is Since it is unevenly distributed on the surface, resolution, printability, etc. are not impaired by the adhesive paint.

Furthermore, in this invention, since the porous thin paper is first impregnated with a solvent, among the dense fiber areas in the thin paper, the dense fiber areas that dry slowly are filled with the solvent first, so that the During the drying process, the adhesive paint is not dried to a higher concentration in the fiber-dense areas of the tissue paper.

In addition, in the manufacturing method of the present invention, both the bonding surfaces of the film and porous thin paper are wetted with paint and solvent, so there is no air entrainment during bonding, and slight wrinkles and wrinkles in the film and thin paper do not occur. A uniform and stable product can be obtained by absorbing and eliminating sagging and tension.

<Example> Examples of this invention will be shown below.

Example 1 FIG. 1 shows an example of this invention.
1 is a thin paper unwinding part, 2 is a solvent impregnated part, 3 is an adhesive paint application part, 4 is a film unwinding part, 5 is a pasting part,
6 is a drying oven, 7 is a mold release agent applying section, and 8 is a base paper winding section.

The thin paper unwinding section 1 contains a porous thin paper 9 made of 100% polyester fiber with a thickness of 40 μm and a basis weight of 13 g/m ³
A biaxially stretched polyester film 10 (CX01 manufactured by Diafoil Co., Ltd.) with a thickness of 3 μm is wound up in the film unwinding section 4, and acetone is stored in the solvent impregnation section 2, and adhesive paint is applied. Part 3 contains vinyl acetate resin (Nitsusetsu P- manufactured by Nippon Carbide Co., Ltd.).
170) in methanol (solid content 5wt%).

Here, the porous thin paper 9 is passed through a solvent impregnation section 2 to be impregnated with acetone, and the film 10 is passed through a paint application section 3 to have a vinyl acetate resin paint applied to its bonded surface. Furthermore, after the porous thin paper 9 and the film 10 are pasted together in the pasting section 5, they are guided by guide rollers 11, . . . and passed through a drying oven 6, where they are dried at a temperature of about 80°C. . At the exit of the drying oven 6, the remaining heat of the base paper is used to pass through the mold release agent coating section 7, and an ethyl acetate solution (as a mold release agent) of a fluorine-based surface modifier (Surflon S-382 manufactured by Asahi Glass Co., Ltd.) is applied to the surface of the paper as a mold release agent. 0.5wt% solids), and the obtained base paper was wound up by the base paper winding section 8.

The coating amount of the adhesive paint was 0.9 g/m ³ and the coating amount of the surface modifier was 0.25 g/m ³ .

When this base paper was made into plates using a flash-type plate-making machine and printed on a rotary press (Auto Printer EP-300, manufactured by Seiki Kogyo), more than 5,000 clear prints were printed.

Example 2 Vinyl chloride-vinyl acetate copolymer resin (manufactured by Denki Kagaku Kogyo Co., Ltd., Denkavinyl) was used as an adhesive paint.
Using 1000AS methyl isobutyl ketone/toluene mixed solution (solid content 10 wt%), methyl isobutyl ketone/toluene mixed solution as a solvent, perfluoroalkyl betaine (manufactured by Asahi Glass Co., Ltd., Surflon S-131) as a mold release agent, A porous thermosensitive base paper was obtained in the same manner as in Example 1.

In this case, the coating amount of adhesive paint is 1.4
g/m ³ , and the coating amount of the release agent was 0.2 g/m ³ .

Furthermore, when the base paper thus obtained was plate-printed in the same manner as in Example 1, more than 5,000 clear prints could be obtained.

Example 3 An aqueous solution (solid content 15 wt%) of vinyl chloride-vinyl acetate copolymer latex (manufactured by Denki Kagaku Co., Ltd., Denka Latex AC-25) as an adhesive coating was heat-set in the same manner as in Example 1. A porous thin paper made of 100% polyester fibers impregnated with water as a solvent and squeezed was applied from the other side to the laminated side of the biaxially oriented polyester film (thickness 1.5μ), which was then laminated and led to a drying oven. and dried at 105°C.

Next, at the outlet of the drying oven, a fluorine-based surface modifier (manufactured by Asahi Glass Co., Ltd., S-
381) in ethyl acetate (solid content: 1 wt%) was applied and dried to obtain a heat-sensitive base paper.

The coating amount of the adhesive paint and the coating amount of the mold release agent were 2.3 g/m ³ and 0.15 g/m ³ in terms of solid content, respectively.

When the base paper thus obtained was made into plates using a flash-type plate-making machine and printed using a rotary mimeograph press, more than 2,000 clear prints faithful to the original were obtained.

Comparative Example 1 In the method of Example 1, porous thin paper was laminated with a biaxially oriented polyester film without impregnating it with a solvent, but the adhesive strength was poor and some parts of the thin paper were partially lifted due to wrinkles and sagging. This caused the stable production of base paper to be impossible.

[Brief explanation of the drawing]

The drawing is a schematic diagram showing an example of base paper production according to the present invention.

Claims (1)

[Scope of Claims] 1. A heat-sensitive stencil printing base paper in which a heat-set biaxially oriented thin film of synthetic resin and a porous thin paper are laminated together using an adhesive paint, wherein the adhesive paint is bonded to the film and the porous thin paper. 1. A base paper for heat-sensitive stencil printing, characterized in that the amount of the porous thin paper gradually decreases from the surface to which it is bonded to the porous thin paper toward the outer surface of the porous thin paper. 2. When laminating a heat-set biaxially stretched thin synthetic resin film and porous thin paper, an adhesive paint is applied to the laminating surface of the film, and the porous thin paper supplied from the other side is impregnated with a solvent; A method for producing a heat-sensitive stencil printing base paper, which comprises: applying the adhesive paint to the outer surface of the porous tissue paper in a gradually smaller amount due to the surface tension of the solvent, and then drying the paper. 3. The manufacturing method according to claim 2, which contains water as a solvent.