JPH0414492A - Thermal stencil paper - Google Patents

Abstract

PURPOSE:To carry out printing excellent in ink passing properties and resolving power and imparting high image quality, in thermal stencil paper wherein a thermoplastic resin film is laminated to one surface of a porous resin film, by providing independent uniform perforations to the porous resin film and forming the perforations so that the shortest distance between the perforations is regularly arranged in the direction oblique to a plate making direction. CONSTITUTION:A thermoplastic resin film 3 is laminated to one surface of a porous resin film 1, if necessary, through an adhesive 2. The porous resin film 1 has independent uniform perforations 21 so that the shortest distance L between the perforations is regularly arranged in the direction oblique to a plate making direction (arrow) and is characterized by that the shortest distance L between the perforations is set to 1 - 50mum, pref., 5 - 30mum and the voids thereof occupying an arbitrary area of 45X85mum are 20% or more in a plan view. The arrangement angle theta of the shortest distance L between the perforations with respect to the plate making direction is 0 - 80 deg., pref., about 45 deg..

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a heat-sensitive mimeograph base paper, and more specifically, an object of the present invention is to provide a heat-sensitive mimeograph base paper that has excellent ink permeability, resolution, etc.

(Prior art and its problems) In the past, the mimeograph printing method has been widely used as a simple printing method. It prints using a thermal head or infrared rays, etc., heats and melts the thermoplastic resin film to form perforations in the form of an image, and prints on a printing material such as paper by passing printing ink from the support side. be.

In the above conventional technology, when paper such as porous tissue paper is used as a support, as a result of the thin thermoplastic resin film, the surface roughness of the paper appears on the surface of the resin film, making contact with the thermal head difficult. As a result, the size, shape, etc. of the perforations that are formed become non-uniform, and the ink permeability of the perforations becomes non-uniform, resulting in uneven density and white spots in the printed image, resulting in poor resolution. There is a problem that expensive printing cannot be done.

In order to solve the above problem, it has been proposed to use a porous synthetic resin film as a support (for example, JP-A-62-199445, JP-A-61-53092, etc.); In some cases, the above-mentioned porous resin film is formed by applying a resin liquid to a suitable support surface using, for example, a gravure roll or belt having an uneven surface structure. Because the cured resin film does not fit into the recesses or is difficult to peel off from the plate, the uniformity of the pores in the porous resin film is poor, resulting in poor ink permeability and problems such as white spots and uneven density on printed matter. There is.

Therefore, an object of the present invention is to solve the above-mentioned drawbacks and to provide a thermal mimeograph base paper having excellent ink permeability, resolution, etc.

(Means for solving problems) The above objects are achieved by the present invention as described below.

That is, the present invention provides a heat-sensitive mimeograph base paper formed by laminating a thermoplastic resin film on one side of a porous resin film, wherein the porous resin film has independent and uniform pores, and the pores The shortest distance between the holes is regularly arranged in a diagonal direction with respect to the plate-making direction, and the shortest distance between the openings is lLLm ~ 50
This is a heat-sensitive mimeograph base paper characterized by having a porosity of 20% or more when viewed planarly in μm and occupying an arbitrary 45 μm×85 μm square.

(Function) When creating a porous resin film, by making the surface uneven structure of the plate have a specific structure and arrangement, the resin liquid will uniformly enter the concave portions of the plate, and the resin liquid will form a bath fat film after the resin liquid has hardened. Since it is easy to peel off, it is possible to provide a heat-sensitive mimeograph base paper that has independent and uniform pores, has excellent ink permeability, and is capable of printing with high image quality such as resolution.

(Preferred Embodiments) Next, the present invention will be described in more detail by citing preferred embodiments.

The thermal mimeograph base paper of the present invention is made by laminating a thermoplastic resin film 3 on one surface of a porous resin film 1 via an adhesive layer 2 as required, as shown in the first figure.

Further, the porous resin 1111 has independent uniform openings 21 as shown in Figure 2, and the shortest distance between the openings is not as shown in Figure 2a, but as shown in Figure 2. Like plate making direction (
The shortest path ML between the openings is 1 μm to 50 μm, preferably 5 to 50 μm.
It is characterized by having a pore size of 30 μm and an aperture ratio of 20% or more when viewed planarly in an arbitrary 45 μm x 85 μm square.

On the other hand, if the shortest distance between the openings is arranged parallel to the plate-making direction as shown in Figure 2a, the resin liquid will uniformly enter the recesses of the plate during the production of the porous resin film. (Also, it is difficult to peel off the cured resin film uniformly.Also, when printing after printing on heat-sensitive mimeograph base paper, printing ink does not uniformly enter the openings 21, making it impossible to print with high image quality.) The arrangement angle θ of the shortest distance between the apertures with respect to the plate-making direction is 10 to 80 degrees, but the preferred angle is 45 degrees.
Before and after.

Further, if the shortest distance between the openings is less than 1 μm, the strength of the porous resin membrane itself is insufficient, while if it exceeds 50 μm, the density and resolution of the printed image will decrease, which is not preferable.

Further, if the porosity of the porous resin film is less than 20%, the density and resolution of the printed image will decrease as described above, while if the porosity is too high, the strength of the resin film will be poor. The preferred porosity is 20 to 80%.

As the material for forming the porous resin film, thermoplastic resins, thermosetting resins, electron beam or ultraviolet curable resins, etc. can be used. Examples of thermoplastic resins include polyethylene, polypropylene, polystyrene, and polyvinyl acetate. , polyacrylate, polymethacrylate, polyvinyl chloride, polyvinylidene chloride, polyacrylonitrile, polyvinyl ether, polyvinyl ketone, polyether, polycarbonate, polyester, polyamide, fluorine resin, polyurethane resin, natural rubber, cellulose resin, etc. Species or mixtures or copolymers, preferably thermoplastic resins that do not melt due to the heat from the thermal head during plate making and are not attacked by the inks used during printing, used in conventional paints, printing inks, etc. Thermosetting resins and radiation-curable resins such as electron beams and ultraviolet rays.
A desired porous resin film is formed by printing and curing ink made of these resins in regular shapes such as circles and polygons on the thermoplastic resin film described below using a gravure roll or belt made as described above. can be formed.

If the resin used is a thermoplastic resin, in addition to the above methods, it may be made porous at the same time as melt extrusion molding by a T-die method, calendar method, embossing method, etc., and then hardened with a cooling roll. Good too.

The electron beam or ultraviolet curable resin preferably used in the present invention essentially contains one or a mixture of various acrylates and methacrylates, such as polyester acrylate, urethane acrylate, epoxy acrylate, polyacetal acrylate, etc., as a reactive oligomer or monomer. It is a component that is crosslinked and cured by electron beams or ultraviolet rays. Furthermore, plasticizers, stabilizers, lubricants, pigments, fillers, etc. can be added to these resin liquids as necessary. Various such radiation-curable resins are available on the market, and any of them can be used in the present invention.

The thickness of the porous resin film is about 5 to 100 μm, preferably about 10 to 50 μm, because if it is too thick, the sensitivity of the heat-sensitive mimeograph base paper will decrease, and if it is too thin, the strength will be insufficient. Further, if the area of each hole is too large, the resolution of the printed image will be reduced, while if it is too small, it will be difficult to form the hole itself, so it is preferably about 1 to 40,000 .mu.m.sup.2. or,
The strength of the resin film after film formation can be adjusted by selecting an appropriate material depending on the intended use, printing machine characteristics, etc. - For boat fishing, tensile strength 50-500 Kg
/c, especially 150-400Kg/crtr
It is preferable that It can be used if the elongation is about 1 to 300%, preferably 5 to 100%.

Thermoplastic resin films used in the present invention include, for example, polyvinyl chloride films, vinyl chloride-vinylidene chloride copolymer films, polyester films, polyolefin films such as polyethylene and polypropylene,
Known films such as polystyrene film and modified cellulose film may be used.

When these thermoplastic resin films are used for thermal mimeograph base paper, the thickness thereof should be 20 μm or less, preferably 10 μm or less, and optimally 1 to 5 μm so that perforations can be easily formed by heating means such as a thermal head. The thickness is .

An example of manufacturing the thermal mimeograph base paper of the present invention is shown in FIG.

In FIG. 3, a thermoplastic resin film 31 or other base material is fed onto a roll 32 or an endless belt having irregularities formed by engraving, etching, etc., and brought into contact with the surface thereof.

The resin liquid 3 is supplied to the roll 32 via the lower liquid supply roll 33.
4 is supplied, excess resin liquid 34 is removed by a doctor 35, and the resin liquid is put into the recess. This resin liquid 34 is transferred to the surface of the thermoplastic resin film 31 by forming holes as shown in FIG. The transferred resin liquid 34 is transferred to the shield 3
The film is cured by energy from an electron beam irradiation device 37, an ultraviolet ray irradiation device, an infrared ray irradiation device, etc. which are sealed at 6, and is wound onto a winding roll 38.

At this time, if a thermoplastic resin film 31 for heat-sensitive mimeograph base paper as described below is used, the obtained laminate can be used as a heat-sensitive mimeograph base paper as it is; A thermal mimeograph base paper can also be formed by transferring the porous resin film to another thermoplastic resin film using an adhesive if necessary.

Of course, the above-mentioned porous resin film can be formed by other methods, for example, by perforating a film with excellent heat resistance and ink resistance in a mesh pattern, or by embossing the above-mentioned thermoplastic resin film and forming the embossed grooves in the film. It is also possible to form the pattern by any other pattern forming method, such as filling the curable resin with the curable resin and curing it.

In the present invention, if necessary, the surface of the porous resin membrane may be coated with various types of paper, especially coarse paper such as Japanese paper, synthetic paper made of chemical fibers such as rayon, vinylon, polyester, acrylonitrile, etc. It is also possible to laminate another porous support such as paper made of a mixture of chemical fibers and natural fibers. In this case, the porous resin film becomes an intermediate layer.

When the porous resin film is laminated on a thermoplastic resin film, or further on thin paper or the like, an adhesive layer 2 may be formed as necessary as shown in the first figure. The adhesive layer may be similar to the adhesive layer in conventional heat-sensitive mimeograph base paper. Further, when the adhesive layer is cured with actinic light such as electron beams or ultraviolet rays, monomers such as acrylic monomers, oligomers, etc. are added to the above-mentioned resin.

The thickness of these adhesive layers is 10 μm or less, preferably 5 μm or less, and optimally 0.5 to 5 μm so that perforations can be easily formed by heating means such as a thermal head.

The thermal mimeograph base paper obtained by the method described above has excellent plate-making properties, but when forming the mimeograph holes by heating the thermoplastic resin film with a thermal head or other method, depending on the conditions, the thermal head may not work properly. It may melt to the thermoplastic resin film and destroy the thermoplastic resin film, or
When a copying hole is formed by exposure through a positive original film, there is a risk that the positive original film may be fused.

In the present invention, in order to solve these drawbacks, a heat fusion prevention layer made of silicone oil, silicone resin, fluorine resin, surfactant, etc. can be formed on the thermoplastic resin film.

Furthermore, in order to provide excellent antistatic properties to the base paper, it is also preferable to add an antistatic agent into the heat-fusion prevention layer. Explain in detail. In the text, parts or percentages are based on weight unless otherwise specified.

First, five types of plates shown in Table 1 below were prepared as plates for preparing porous resin membranes. The shape of the plate is as shown in Figure 2.

Example 1 Polyester polyol (Plaxel 205AL)
220 parts Isophorone diisocyanate 136 parts Hydroxyethyl methacrylate 63 parts Tin catalyst
The reactive oligomer obtained from a small amount is coated on the surface of a polyethylene terephthalate film with a film thickness of 1.8 μm using the plate A described above according to the method shown in Figure 3 and cured with electron beam, and then silicone oil is applied to the surface of the polyester film. jl
(X-22-161B, manufactured by Shin-Etsu Silicone ■) to obtain a thermal mimeograph base paper of the present invention.

Example 2 A thermal mimeograph base paper of the present invention was obtained in the same manner as in Example 1 except that the plate B was used as the plate in Example 1.

Example 3 A thermal mimeograph base paper was obtained in the same manner as in Example 1 except that the plate C was used as the plate in Example 1. This product has problems with transportability due to its lack of strength. Therefore, porous tissue paper coated with acrylic emulsion adhesive is adhered to the porous resin surface of the base paper, and silicone oil is applied to the polyester film surface. A thermal mimeograph base paper of the present invention was obtained by coating. The tensile strength of the porous resin membrane alone was 35.8 Kg/cd.

Example 4 Electron beam curable resin liquid (Art Resin UN-900PEP
, manufactured by Itagami Kogyo ■) and 3 parts of a polymerization initiator (Irgacure 184, manufactured by Ciba Geigy) were applied to the surface of a polyethylene terephthalate film with a film thickness of 1.8 μm using the plate B described above in the method shown in Figure 3. The polyester film was cured by irradiating ultraviolet rays with an 80 W/cmXl lamp, and silicone oil was further applied to the surface of the polyester film to obtain a thermal mimeograph base paper of the present invention.

Example 5 Thermoplastic resin (Efselen v-ioo, Sumitomo Chemical Co., Ltd.
) was melt-extruded at 200° C. and 300 kg/c resistance to make it porous as in version B, to create a porous resin film. This porous resin film was laminated with a 1.8 μm polyethylene terephthalate film coated with an acrylic emulsion adhesive, and silicone oil was further coated on the polyester surface to obtain a thermal mimeograph base paper of the present invention.

Comparative Example 1 Using thin paper as a porous support, a 1.8 μm polyethylene terephthalate film and an electron beam curable adhesive mainly composed of urethane acrylate were bonded together, cured at an irradiation dose of 3 Mrad, and then silicone oil was applied to the polyester surface. was coated to obtain a thermal mimeograph base paper of a comparative example.

Comparative Example 2 A heat-sensitive mimeograph base paper of a comparative example was obtained using the above-mentioned plate as the plate in Example 1, but in the same manner as in Example 1 except for the above-mentioned plate.

Comparative Example 3 A thermal mimeograph base paper of a comparative example was obtained in the same manner as in Example 1 except that the plate E was used as the plate in Example 1.

Using the thermal mimeograph base papers of the present invention and comparative examples described above, plate making and printing were performed using a plate making printing machine (Gakken APX8080), and the results shown in Table 2 below were obtained.

(Hereinafter referred to as margins) It is possible to provide a thermal mimeograph base paper that has excellent passability from 1 to 21 and is capable of printing with high image quality such as resolution.

[Brief explanation of drawings]

FIG. 1 is a diagram illustrating the cross section of the thermal mimeograph base paper of the present invention, FIG. 2 is a diagram illustrating the arrangement of the apertures, and FIG. 3 is a diagram diagrammatically explaining the method for manufacturing the thermal mimeograph base paper. It is a diagram. (Effects) According to the present invention as described above, when creating a porous resin film, by making the surface uneven structure of the plate have a specific structure and arrangement, the resin liquid can uniformly enter the concave portions of the plate, and After the resin liquid hardens, the side fat film can be easily peeled off, so independent and uniform pores are formed. 31: Thermoplastic resin film 32: Coating roll 33: Liquid absorbing roll 34: Resin liquid 35: Doctor 36: Shield 37: Electron beam irradiation device 38: Winding roll Patent applicant Dainippon Printing Co., Ltd. Person Patent Attorney Yoshi 1) Katsuhiro -J (1 other person) Figure 2 Figure 3

Claims (2)

[Claims] (1) In a heat-sensitive mimeograph base paper formed by laminating a thermoplastic resin film on one side of a porous resin film, the porous resin film has independent and uniform pores, and the distance between the pores is the shortest. The hole area is regularly arranged diagonally to the plate-making direction, the shortest distance between the holes is 1 μm to 50 μm, and the hole area occupies an arbitrary 45 μm x 85 μm square when viewed in plan. 20% or more of heat-sensitive mimeograph paper. (2) The heat-sensitive mimeograph base paper according to claim 1, wherein the resin film is made of a radiation-curable resin.