JPH071851A - Thermal stencil paper - Google Patents

Abstract

PURPOSE:To provide thermal stencil paper capable of printing a positive image by a thermal head, uniform in its pore size and ink passing quantity and forming an image excellent in sharpness. CONSTITUTION:In thermal stencil paper 1 wherein an org. and/or inorg. fine particle layer 3 is provided on the surface of a thermoplastic polymer film 2 with a thickness of 0.5-20mum using a polymer binder 4, the height of the surface unevenness of the polymer binder layer 4 is set to 0.1-20mum and the interval of the unevenness is set to 1-40mum.

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 sheet, and more particularly to a heat-sensitive stencil sheet perforated by a thermal head or the like.

[0002]

2. Description of the Related Art FIG. 4 is a sectional view showing a conventional heat-sensitive stencil sheet. A conventional heat-sensitive stencil sheet 10 has a structure in which a thermoplastic polymer film 2 and a porous support 11 such as porous thin paper are bonded together with an adhesive, and further heat fusion with a thermal head is prevented. Therefore, a release layer is provided on the surface of the thermoplastic polymer film. The plate making of this heat-sensitive stencil sheet is such that the characters and the like are printed in reverse images by the heat of the thermal head from the film side, and the film is melt-punched.
At the time of printing, ink is supplied from the side of the porous support of the heat-sensitive stencil sheet. However, in such a heat-sensitive stencil sheet, since the thermoplastic polymer film and the porous support are bonded with an adhesive, the perforation diameter of the contact portion between the film and the porous support becomes non-uniform, and the ink Since the passage is blocked by the porous support, the sharpness of the image is deteriorated. Further, when punching using a thermal head, it is necessary to print with an inverse image, so that there is a drawback that it is not possible to easily carry out plate making using a general thermal printer or word processor.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems of the prior art, to enable normal image printing with a thermal head, to have a uniform perforation diameter and ink passage amount, and to provide a clear image. It is to provide a heat-sensitive stencil sheet having excellent properties.

[0004]

The present invention has a thickness of 0.5 to
A heat-sensitive stencil sheet in which an organic and / or inorganic fine particle layer is provided on a surface of a thermoplastic polymer film having a thickness of 20 μm with a polymer binder, and the height of irregularities on the surface of the polymer binder layer is 0.1 to 20 μm. The heat-sensitive stencil sheet is characterized in that the interval of the irregularities is in the range of 1 to 40 μm.

[0005]

1 is a sectional explanatory view of the heat-sensitive stencil sheet of the present invention,
FIG. 2 is an explanatory diagram of perforation of the heat-sensitive stencil sheet of the present invention. In FIG. 1, the heat-sensitive stencil sheet 1 is composed of a thermoplastic polymer film 2, a fine particle layer 5 composed of fine particles 3 and a polymer binder 4 having specific heights and intervals of irregularities. The heat-sensitive stencil sheet 1 has no porous support. As shown in FIG. 2, the heat-sensitive stencil sheet 1 has the fine particle layer 5 side supported by the supporting member of the platen roller 8 and the film surface of the thermoplastic polymer film 2 in contact with the thermal head 7, The holes 9 are formed by heat drilling. At the time of punching with a thermal head, an air heat insulating layer 6 is formed between the platen roller 8 and the fine particle layer 5 having a specific unevenness.

Since the perforation property of the thermoplastic polymer film has a great influence on the sharpness of the image, it is necessary to efficiently and uniformly apply the heat of the thermal head to the thermoplastic polymer film. In the present invention, since the heat insulating layer 6 for air is formed on the opposite side of the surface of the thermoplastic polymer film which is in contact with the thermal head as described above, the heat of the thermal head can be transferred only to the thermoplastic polymer film. It becomes possible, and it becomes possible to perforate uniform holes. Further, since the heat-sensitive stencil sheet of the present invention does not have a porous support as in the conventional case, it is possible to print a normal image by a thermal head, and further the ink passage is improved so that the sharpness of the image can be improved. it can.

Examples of the thermoplastic polymer film used in the present invention include polyethylene, polypropylene, polyvinyl chloride, polyvinylidene chloride, polyester, polystyrene, polyurethane, polycarbonate, acrylic resin, silicone resin, and the like. Particularly, polyvinylidene chloride and polyester are preferable. The thickness of the thermoplastic polymer film is in the range of 0.5 to 20 μm, preferably 1 to 15 μm. If the thickness of the film is less than 0.5 μm, the handling and strength are poor, and
If it exceeds μm, it becomes difficult to perforate with the heat generated by the thermal head.

The fine particles used in the present invention include acrylic resin, urethane resin, silicone resin, urea-formalin condensation resin, phenol resin, epoxy resin, benzoguanamine resin, organic fine particles such as polystyrene, silicon dioxide, calcium carbonate, sulfuric acid. Calcium, talc,
Examples include inorganic fine particles such as clay and mica. As the organic fine particles, those having heat resistance are preferable. The shape of the fine particles is not particularly limited, and may be spherical, plate-like, flake-like,
It may be indefinite shape or hollow shape thereof. These fine particles can be used alone or in combination. As the polymer binder used in the present invention,
The polymer material used for the above-mentioned thermoplastic polymer film can be used, but from the viewpoint of adhesiveness, it is preferable to use the same or similar material as the material used for the thermoplastic polymer film.

In the present invention, the height of the irregularities on the surface of the fine particle layer composed of the fine particles and the polymer binder is 0.1.
To 20 μm, preferably 0.2 to 10 μm, and the interval between the irregularities of the fine particle layer is 1 to 40 μm, preferably 2 to 30 μm. When the height of the irregularities on the surface of the fine particle layer is less than 0.1 μm, the thickness of the heat insulating layer of air formed between the fine particle layer and the supporting member such as the platen roller at the time of punching with the thermal head is low, so that a sufficient heat insulating effect is obtained. Cannot be obtained, and the perforability of the thermoplastic polymer film cannot be improved. If it exceeds 20 μm, the unevenness of the fine particles is too large as compared with the thickness of the thermoplastic polymer film, so that the amount of the polymer binder required to fix the fine particles to the film increases, resulting in the thickness of the binder layer. Becomes thicker and the thermal efficiency of the thermal head decreases. Since the height of irregularities on the surface of the fine particle layer is almost determined by the size of the fine particles, the size of the fine particles to be used should be 0.1-2
By setting the range of 0 μm, preferably 0.2 to 10 μm, the height of the unevenness on the surface of the fine particle layer is 0.1 to 20 μm.
Can be in the range of.

Further, when the interval between the irregularities on the surface of the fine particle layer is 1 μm or less, the amount of fine particles per unit area increases, and as a result, the capacity of the heat insulating layer decreases and the thermal efficiency decreases. On the other hand, when the thickness exceeds 40 μm, the size becomes close to that of one heating element of the thermal head, a heat insulating layer is not formed on the surface opposite to the film surface in contact with the thermal head, and the thermal efficiency of the thermal head decreases. The weight ratio of the fine particles and the polymer binder is 50/1 (fine particles / polymer binder).
~ 1/1 is preferable, and 20/1 to 2/1 is more preferable. If the amount of the fine particles used exceeds 50 times the amount of the polymer binder, the fixing performance of the fine particles deteriorates. If the amount of the fine particles used is less than the amount of the polymer binder, the capacity of the heat insulating layer formed becomes small and the heat insulating effect decreases. To do.

For the fine particle layer, for example, fine particles are dispersed in a polymer binder solution dissolved in a solvent, and the dispersion is applied onto a thermoplastic polymer film, for example, by coating with a roll coater, a gravure coater, a wire bar coater or the like. It can be formed by applying a coating method and then evaporating the solvent. The dispersion may contain a dispersant, a curing agent, a leveling agent, etc., if necessary. The coating amount of the polymer binder is preferably 0.1 to 10 g / m ² from the viewpoint of thermal efficiency of the thermal head. The fine particle layer is provided on the surface opposite to the surface of the thermoplastic polymer film in contact with the thermal head, but is applied to both surfaces of the film to prevent film fusion on the surface in contact with one layer of the thermal head. It can also be a release layer.
In this case, the fine particle layer provided on the thermal head side is
Since the thermal efficiency of the thermal head decreases, it is preferable that the particles are as small as possible.

[0012]

EXAMPLES The present invention will now be described in detail with reference to examples, but the present invention is not limited thereto. Example 1 (1) Preparation of heat-sensitive stencil base paper A coating solution having the following composition was dispersed in a ball mill for 3 hours, and then the dispersion was coated on a polyvinylidene chloride film having a thickness of 7 μm with a wire bar and dried. To form a fine particle layer. The height of the irregularities of the fine particle layer was 5 to 7 μm, and the interval between the irregularities was 20 μm on average. The height and interval of the irregularities of the fine particle layer were measured by a surface roughness meter (manufactured by Tencor Co.,
It was measured by the alpha step 200) (hereinafter the same). Coating liquid: Nylon resin fine particles (average particle size 4 to 5 μm) 10 parts by weight PVC-vinyl acetate copolymer 2 parts by weight Toluene 58 parts by weight Methyl ethyl ketone 30 parts by weight

(2) Perforation of heat-sensitive stencil base paper Silicone oil is applied to the opposite side of the fine particle layer of the heat-sensitive stencil base paper obtained in (1), the silicone oil coated surface is brought into contact with a thermal head of 400 dpi, and the fine particles are used. The surface of the layer was supported by a platen roller and a positive image was perforated with an applied energy of 0.07 mj / dot. The perforated image consists of all solid parts, 10 lines / mm fine line parts and character parts.
It was a kind. The state of perforation in the image area is determined by microscope (magnification 150
The results are shown in FIG. 3, and it was confirmed that uniform holes 9 were formed. (3) Printing Using the heat-sensitive stencil sheet perforated in (2), the printing ink is supplied from the thermoplastic polymer film side, and printing is performed by a printing machine PG-10 (made by Ideal Science Co., Ltd.), and all solid parts are printed. And the reproducibility of the thin line portion of 10 lines / mm were examined, and the results are shown in Table 1.

Example 2 A coating solution having the following composition was dispersed by a ball mill for 2 hours, and then the dispersion was coated on a polyester film having a thickness of 3 μm with a wire bar and dried to form a fine particle layer. The height of the irregularities of the fine particle layer was 2 to 3 μm, and the average interval of the irregularities was 15 μm. Coating liquid: Silicone resin fine particles (average particle size 2 μm) 10 parts by weight Polyester resin 2 parts by weight Toluene 58 parts by weight Methyl ethyl ketone 30 parts by weight The obtained heat-sensitive stencil sheet was perforated and printed in the same manner as in Example 1. The uniformity of all solid areas and the reproducibility of fine lines of 10 lines / mm were examined, and the results are shown in Table 1.

Example 3 A coating liquid having the following composition was dispersed by a ball mill for 2 hours, and then the dispersion was coated on a polyester film having a thickness of 2 μm with a wire bar and dried to form a fine particle layer. The height of the irregularities of the fine particle layer was 0.5 to 1 μm, and the interval between the irregularities was 2 μm on average. Coating liquid: Acrylic resin hollow fine particles (average particle size 0.5 μm) 10 parts by weight Acrylic resin 2 parts by weight Toluene 58 parts by weight Methyl ethyl ketone 30 parts by weight The obtained heat-sensitive stencil sheet was perforated in the same manner as in Example 1, After printing, the uniformity of all solid areas and the reproducibility of fine lines of 10 lines / mm were examined, and the results are shown in Table 1.

Example 4 A coating solution having the following composition was dispersed by a ball mill for 2 hours, and then the dispersion was coated on a polyester film having a thickness of 3 μm with a wire bar and dried to form a fine particle layer. The height of the irregularities of the fine particle layer was 5 to 8 μm, and the spacing between the irregularities was 20 μm on average. Coating liquid: Silicon dioxide fine particles (average particle size 4 to 7 μm) 8 parts by weight Polyester resin 2 parts by weight Toluene 60 parts by weight Methyl ethyl ketone 30 parts by weight The obtained heat-sensitive stencil sheet was perforated by the same method as in Example 1 and printed. Then, the uniformity of the entire solid portion and the reproducibility of the thin line portion of 10 lines / mm were examined, and the results are shown in Table 1.

Example 5 A coating solution having the following composition was dispersed in a ball mill for 2 hours, and then the dispersion was coated on a polyester film having a thickness of 10 μm with a wire bar and dried to form a fine particle layer. The height of the irregularities of the fine particle layer was 8 to 10 μm, and the interval between the irregularities was 20 μm on average. Coating liquid: Benzoguanamine resin fine particles (average particle size 3 μm) 10 parts by weight Styrene-butadiene copolymer 2 parts by weight Toluene 68 parts by weight n-hexane 20 parts by weight The obtained heat-sensitive stencil sheet was applied with an energy of 0.09 mj /
Punching was performed in the same manner as in Example 1 except that the dots were punched, and printing was performed to check the uniformity of the entire solid portion and the reproducibility of the thin line portion of 10 lines / mm, and the results are shown in Table 1.

Comparative Examples 1 and 2 A heat-sensitive stencil sheet prepared by laminating a 7 μm thick polyvinylidene chloride film and a gauze (Comparative Example 1) and a heat-sensitive stencil sheet prepared by laminating a 2 μm thick polyester film and Japanese paper (Comparative Example 2). Stencil printing was performed in the same manner as in Example 1 except that the image of the reverse image was punched and the printing ink was supplied from the side of the gauze or Japanese paper, and the results are shown in Table 1.
The perforation state of the perforation image of Comparative Example 1 was observed with a microscope (magnification: 150).
5), the results are shown in FIG. 5, and it was confirmed that the perforated holes 9 were non-uniform, and the non-perforated portions 12 were present.

[0019]

[Table 1] From Table 1, it is shown that the heat-sensitive stencil sheet of the present invention has a good perforated state and is excellent in the uniformity of solid portions and the reproducibility of fine lines.

[0020]

According to the heat-sensitive stencil sheet of the present invention, a thermoplastic polymer film which does not come into contact with the thermal head at the time of perforation is provided by providing a fine particle layer having specific heights and intervals of irregularities on the surface of the thermoplastic polymer film. Since the heat insulating layer can be formed on the surface side, the thermal efficiency of the thermal head can be improved to improve the perforation property of the thermoplastic polymer film, and since there is no porous support, the ink during printing can be formed. Since it is possible to make the passing amount of the ink uniform, it is possible to improve the uniformity of the solid portion of the printed image and the reproducibility of fine lines. Furthermore, since the heat-sensitive stencil sheet can be punched with a normal image, plate making by a general thermal printer or word processor becomes possible.

[Brief description of drawings]

FIG. 1 is an explanatory sectional view of a heat-sensitive stencil sheet of the present invention.

FIG. 2 is an explanatory diagram of perforation of the heat-sensitive stencil sheet of the present invention.

FIG. 3 is a micrograph showing a perforated state of the heat-sensitive stencil sheet of the present invention.

FIG. 4 is an explanatory cross-sectional view of a conventional heat-sensitive stencil sheet.

FIG. 5 is a micrograph showing a perforated state of a conventional heat-sensitive stencil sheet.

[Explanation of symbols]

1, 10 ... Thermal stencil stencil paper, 2 ... Thermoplastic polymer film, 3 ... Fine particles, 4 ... Polymer binder, 5 ... Fine particle layer, 6 ... Thermal insulation layer, 7 ... Thermal head, 8 ... Platen roller, 9 ... Hole, 11 ... Porous support, 12 ... Unperforated part.

Claims (1)

[Claims] 1. A surface of a thermoplastic polymer film having a thickness of 0.5 to 20 μm is made of an organic and / or organic polymer by a polymer binder.
Alternatively, it is a heat-sensitive stencil sheet provided with an inorganic fine particle layer, wherein the height of the unevenness on the surface of the fine particle layer is in the range of 0.1 to 20 μm, and the interval of the unevenness is in the range of 1 to 40 μm. Characteristic heat sensitive stencil base paper.