JP2002200858A - Master for heat-sensitive stencil printing, method for stencil printing and apparatus for stencil printing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a master for heat-sensitive stencil printing by which good quality of an image with strong stiffness and tensile strength can be obtained and elongation can be prevented from being generated when the master is printed and in addition, fibers are piled up and an adhesive is accumulated and perforation by a thermal head is not hindered and in addition, unevenness of printing caused by piling-up of the fibers is not generated. SOLUTION: The master for heat-sensitive stencil printing characterized by successively laminating a porous resin membrane and a porous fiber membrane consisting of a fiber substance on one face of a thermoplastic resin film and additionally laminating at least one layer of a porous membrane on these laminated membranes is provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a master for thermal stencil printing, a stencil printing method, and a stencil printing machine.

[0002]

2. Description of the Related Art A porous thin paper or the like is used as an ink-permeable support (hereinafter may be simply referred to as "support") on a thermoplastic resin film (hereinafter sometimes simply referred to as "film") with an adhesive. A master for heat-sensitive stencil printing is known in which a sticking prevention layer is provided on a film surface for preventing sticking with a thermal head. Actually, a heat-sensitive stencil master (hereinafter, referred to as a thin tissue paper) in which hemp fiber or a mixture of hemp fiber and synthetic fiber or wood fiber is laminated with an adhesive as a porous thin paper, and a stick prevention layer is provided on the film surface. (Sometimes simply "master") is widely used.

[0003] However, such a conventional master for heat-sensitive stencil printing has the following problems since a support made of fibers is present on the upper surface of the film. (1) A large amount of adhesive accumulates in the shape of birds in the area where the film and the film are in contact with each other, making it difficult for the thermal head to perforate the area. Also,
That portion hinders the passage of the ink, causing uneven printing. (2) The fibers themselves impede the passage of ink, causing print unevenness.

[0004] In consideration of these points, several heat-sensitive stencil masters have been proposed. For example, JP-A-3-1
Japanese Patent No. 93445 discloses a support made of porous thin paper using ultrafine fibers having a fineness of 1 denier or less. According to this, the problem (1) is solved,
The problem (2) remains.

Japanese Patent Application Laid-Open No. Sho 62-198459 discloses a method of forming a heat-resistant resin pattern having a substantially closed shape on a film by using a printing method such as gravure, offset, or flexo. . However, it is difficult to print a pattern having a line width of 50 μm or less with the current printing technology, and even if it is possible, the productivity is low and the cost is high. Moreover, in general, when the line width is 30 μm or more, the heat-resistant resin hinders perforation by the thermal head, and printing unevenness occurs.

JP-A-4-7158 discloses a master for heat-sensitive stencil printing by applying a mixture of a water-dispersible polymer and fine particles such as colloidal silica to the film surface and drying to form a porous layer. Is manufactured using a print Gokko plate making machine (manufactured by Riso Kagaku Kogyo Co., Ltd.), and printing is performed using EPSON, HG-4800 ink (for ink jet system).
However, the porous layer obtained by this method has poor printing ink properties, and conventional thermal stencil printing inks are not practical because a sufficient density cannot be obtained during printing. In addition, this layer itself does not have a sufficient heat insulating effect, and is inferior in perforation properties of the film.

Japanese Patent Application Laid-Open No. 54-33117 discloses a printing master consisting essentially of only a film without using a support.
Although the problem (2) is solved, it causes a new problem. One is that when the film is less than 10 μm thick, its “stiffness” is weak,
This makes transport difficult.

As a solution to this, Japanese Patent Publication No. 5-705
Japanese Patent Application Laid-Open No. 95-205 proposes that the film is wound around the peripheral wall of the plate cylinder of the printing machine without being cut, and the entire film rotates together with the rotation of the plate cylinder during printing. However, in this method, the film and the plate discharging unit rotate together with the rotation of the plate cylinder during printing, so that the moment of rotation increases and the displacement of the center of gravity from the rotation axis is large. Heavy,
Must be bigger. Further, when the film has a thickness of 5 μm or more, its thermal sensitivity becomes small, and it becomes difficult to perform perforation by a thermal head. Furthermore, the ratio of the energy applied from the heating means to the platen lost through the master is increased, so that less energy is used for drilling and drilling is difficult.

[0009]

SUMMARY OF THE INVENTION The present invention has been made in view of the state of the prior art as described above, and has the following objects. 1. To provide a heat-sensitive stencil master having a support for increasing the tensile strength of the master and preventing the master from stretching and breaking during printing. 2. An object of the present invention is to provide a thermosensitive stencil master having a support in which the stiffness of a thermoplastic resin film is increased and the perforation sensitivity of the film is improved by a heat insulating effect. 3. To provide a master for heat-sensitive stencil printing with a small amount of ink adhesion, no printing unevenness, and a small back stain on printed matter. 4. To provide a stencil printing method and a printing apparatus using the thermosensitive stencil master.

[0010]

The present inventor has studied a master for heat-sensitive stencil printing from various angles.
The following research results were obtained. (A) It is desirable that a support consisting of only a fibrous substance that prevents the passage of ink and prevents perforation by a thermal head should not be present immediately above the film. (B) However, if the support does not have the fibrous substance, the master has low tensile strength and causes print elongation. (C) The support preferably has relatively small contact points with the film, does not hinder the passage of ink, and provides sufficient stiffness and tensile strength for transport on the printing press. (D) In order to obtain strength enough to withstand printing, the components must have a certain thickness and volume.

As a result of further studies based on these findings, the master for thermosensitive stencil printing has a thermoplastic resin film in which a porous resin film is laminated on one surface and a porous fiber film made of fibrous material is laminated on the surface in this order. Further, it has been confirmed that it is desirable that one or more porous films are laminated on these laminated films, and the present invention has been completed.

That is, according to the present invention, a porous resin film and a porous fiber film made of a fibrous substance are sequentially laminated on one surface of a thermoplastic resin film, and a porous film is further formed on these laminated films. A master for thermosensitive stencil printing characterized by laminating one or more films is provided.

Further, according to the present invention, in the above structure, the range of the porosity of the porous resin film in contact with the perforated area D of the plastic resin film is (−0.
0063D + 61)% or more (D ≧ 314 μm ² )
A stencil printing master is provided.

According to the present invention, in the above configuration, the total area of the holes having a diameter of 5 μm or more in terms of a perfect circle on the surface of the porous resin film is 4 to 80% of the total surface area.
% Is provided.

Further, according to the present invention, in the above configuration, the total area of the holes having a diameter of 5 μm or more in terms of perfect circle on the surface of the porous resin film is 50% of the total opening area.
A master for thermal stencil printing characterized by the above is provided.

Further, according to the present invention, in the above construction, when the thermoplastic resin film is perforated so that the film surface has an opening area ratio of 20% or more, a value measured by a gas permeability tester is used. Is 1.0 to 157 cm ³ / c
A heat-sensitive stencil master is provided, characterized in the range of m ² · sec.

Further, according to the present invention, the thermal stencil printing master according to any one of the above is used, and a hole is perforated by a thermal head so that at least a part of the porous resin film remains behind the perforated portion after perforation. A stencil printing method is provided.

Further, according to the present invention, there is provided a plate making apparatus for making a plate by heat-melting and perforating the heat-sensitive stencil master described in any one of the above, and a plate cylinder around which the plate-formed heat-sensitive stencil master is wound. And an ink supply mechanism provided inside the plate cylinder, and a pressing device for pressing a printing sheet against the thermosensitive stencil master wound around the outer peripheral surface of the plate cylinder. A stencil printing device is provided.

The term "porous resin film" as used herein refers to a porous film formed by, for example, precipitating and coagulating a resin dissolved in a solvent. When the film is compared to a floor on a film, FIG. Collection of cells with multiple ceilings or Figure 2
1 means a film formed by an aggregate of open cell cells, a granular film of FIG. 3, or an aggregate film formed by sticking fibrous resins together.
The constituent elements 4b constituting the porous resin films 4 are connected to each other. Also, "porous fiber membrane"
It means a film formed of tissue paper made of fibrous substances such as vegetable fibers such as cotton and hemp, and synthetic fibers such as polyester and polyvinyl alcohol.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiments of the present invention will be described below in more detail with reference to the drawings. A schematic cross section of a master for thermosensitive stencil printing provided with a support having the porous resin film, the porous fiber film, and the porous film of the present invention is shown in FIG. 2, for example. In FIG. 2, reference numeral 4 denotes a porous resin film;
Is a porous resin film opening, 1 is a thermoplastic resin film, 7
Denotes a porous fiber membrane, and 8 denotes a porous membrane.

The average pore diameter of the porous resin film 4 is usually 1 to
It is 50 μm, preferably 2 to 30 μm. If the average pore diameter is less than 1 μm, the ink permeability is poor, and if a low-viscosity ink is used in order to obtain a sufficient amount of ink passage, the image may bleed or be wrapped around the printing drum during printing. A phenomenon occurs in which the printing ink seeps out of the rear end of the master. In addition, the porosity in the porous resin film is often low, and it is easy to hinder perforation by the thermal head. If the average pore size exceeds 50 μm, the effect of suppressing the ink by the porous resin film is reduced, and the ink between the printing drum and the film is excessively extruded during printing, causing defects such as back stains and bleeding. If the pore size is too small or too large, good print quality cannot be obtained.

The porous resin film 4 only needs to have a structure having a large number of voids inside and on the surface of the film, and the voids are continuous in the thickness direction in the porous film from the viewpoint of ink permeability. It is desirable that the film has a structure and penetrates in the ceiling direction when the film is used as a floor. However, at the boundary between the porous resin film and the film, the porous resin film 4 may cover and close the film 1 as long as the perforation by the thermal head is not hindered. The thickness of the resin constituting the porous resin film 4 that covers the film 1 without hindering the perforation by the thermal head varies depending on the type of the resin constituting the film, the thermal sensitivity of the film, and the like. The combined thickness is 7 μm or less.

On the surface of the porous resin film 4, the total opening area of the holes having a diameter of 5 μm or more when converted into a perfect circle is 4 to 80%, preferably 10 to 60% of the total surface area. If the ratio is less than 4%, perforation and passage of ink by the thermal head are likely to be hindered. If it exceeds 80%, the strength of the porous resin film becomes weak, and the film is broken during printing.

The porous resin film 4 has a structure completely different from the porous portion of the conventional stencil printing master. The individual part forming the structure is composed of an irregularly shaped rod-like, spherical, or branch-like aggregated joint, and the structure is determined by the manufacturing conditions of the resin film, for example, the type of the resin, the solid concentration of the liquid. ,
It depends on the type of solvent, the amount of resin liquid applied, the temperature of drying the resin liquid, the temperature of the coating atmosphere, the humidity and the like. In particular, the influence of the temperature of the resin solution, the temperature of the coating atmosphere, and the humidity is also large.

The porous resin film 4 is composed of an aggregated joint of an irregular rod, sphere, or branch having a structure different from the porous portion of the conventional stencil master as described above. By doing so, fine and uniform voids can be formed on the film, so that it is possible to obtain an effect that an image with excellent perforation and good filling can be obtained.

In forming the porous resin film 4, if the temperature of the resin liquid is lower than 10 ° C., the resin liquid is liable to gel, and it is difficult to apply the solution. It becomes difficult to form a conductive resin film. Therefore, the temperature of the resin liquid is preferably from 10 to 30C. Further, the coating atmosphere temperature is preferably 10 to 30 ° C.

When the humidity of the coating atmosphere exceeds 50% RH, the amount of water adsorbed on the film surface increases, and as a result, the wettability with the coating liquid is reduced, so that the adhesion between the porous resin film and the film is poor. Therefore, the humidity of the coating atmosphere is preferably 50% RH or less.

The master for heat-sensitive stencil printing of the present invention has a diameter of 5 μm when converted to a perfect circle on the surface of the porous resin film 4.
The total opening area of the above holes is 50% or more of the total opening area,
Desirably, it is 70% or more. The ratio is 5
If it is less than 0%, perforation and passage of ink by the thermal head are likely to be hindered.

The thickness of the porous resin film 4 is 5 to 100 μm.
m, preferably 6 to 50 μm. If the thickness is less than 5 μm, it is difficult to obtain sufficient film strength, and it is difficult for the porous resin film to remain behind the perforated portion after perforation by the thermal head. Cheap. On the other hand, if it exceeds 100 μm, the ink-passing property becomes poor.

The effect of the porous resin film 4 for suppressing the amount of ink transferred is greater as the film is thicker, and the amount of ink transferred to printing paper during printing can also be adjusted by the thickness of the porous resin film 4. For example, when the average pore size of the porous resin film 4 is 20 μm or less, the thicker the porous resin film layer, the more difficult it is for the printing ink to pass through. Therefore, the amount of the ink transferred to the printing paper is controlled by the thickness of the layer. Can be.

When the thickness of the porous resin film 4 after coating is larger than the target thickness, the thickness can be reduced to the target thickness by a means such as pressing with a calender. If the thickness of the layer is non-uniform, printing unevenness may occur, so it is desirable that the thickness is uniform. The thickness is measured with substantially no load or under a very small load.

The adhesion amount of the porous resin film 4 is 0.5 to 25.
g / m ² , preferably ² to 15 g / m ² , especially ^{2 to} 7 g / m ²
m ² is desirable. If it is less than 0.5 g / m ^2, it is difficult to obtain sufficient film strength. Conversely, if it exceeds 25 g / m ² , the passage of ink is hindered and the image quality is deteriorated.

The density of the porous resin film 4 is usually 0.01 to
In 1 g / cm ^3, desirably 0.1 to 0.5 g / cm ^3. When the density is less than 0.01 g / cm ³ , the strength of the film is insufficient, and the film itself is easily broken. Conversely, the density is 1 g / c
If it exceeds m ³ , the passage of ink is hindered and the image quality deteriorates.

In order to more effectively perforate the film by the thermal head, at least a part of the porous resin film, that is, a portion of the porous resin film that comes into contact with the film, may be softened at a temperature of 150 ° C. or less. desirable. In order to adjust the pore size, shape, strength, and stiffness of the membrane, it is preferable that the porous resin membrane contains a pigment.

The master for heat-sensitive stencil printing of the present invention using the support having the porous resin film 4, the porous fiber film 7, and the porous film 8 as described above is a stencil printing machine Preport V.
T3820 (manufactured by Ricoh Co., Ltd.) and its ink (VT60
011, lotno. 960604-22), the applied pulse width is set to be longer than the 7% standard condition, and the
A good image can be obtained when plate-making printing (printing speed 3rd speed) is performed in a 0% RH environment [the print image density is 0.7 to 1.3, preferably 0.9 to 1.25 ( Mac
beth RD914 densitometer)], the structure of the porous resin film 4 of the present invention is clearly different from the structure of the porous resin film described in JP-A-4-7198.

The VT60011 ink (lot
no. 960604-22) has a viscosity of HAA
When measured at a shear rate of 20 (1 / S) using a rotor PK30-4.0 with a KE CV20, 1
It was 50 Poise.

When the ink for ink-jet printing is used in the master for heat-sensitive stencil printing of the present invention, the amount of transferred ink becomes too large, bleeding occurs, and a clear image cannot be obtained. The stiffness of the master for heat-sensitive stencil printing of the present invention is desirably a bending stiffness of 5 mN or more (by Lorentzen Stiffness tester). If the bending stiffness is less than 5 mN, it may be difficult to transport the master for thermosensitive stencil printing on a printing machine.

When the thermosensitive stencil master of the present invention is perforated so that the thermoplastic resin film surface of the thermosensitive stencil master has an opening area ratio of 20% or more, the value measured by a gas permeability tester is 1%. 0.0-157cm ³ / cm ²・
Those in the range of seconds are preferred. The opening area ratio referred to here is the total area of the through-holes on the film surface of the heat-sensitive stencil master when the heat-sensitive stencil master is subjected to solid plate making by a thermal head, a laser, a flash lamp, or the like. This is the ratio of the solid area per unit area.

When the opening area ratio is less than 20%, it is necessary to use an ink having a very low viscosity in order to secure the image density, and in such a stencil printing system, the uniformity of the solid portion, Or the reproducibility of the thin line is not good.

In this case, the air permeability is 1.0 cm ³ / cm ² ·
If it is less than a second, the ink permeability is poor, and if a low-viscosity ink is used to obtain a sufficient amount of ink passage, the image will bleed and the side of the print drum or after the master that is wound around during printing. The phenomenon that the printing ink seeps out from the edge occurs. In addition, the porosity in the porous resin film and the porous fiber film is often low, and it is easy to hinder perforation by the thermal head. When the air permeability exceeds 157 cm ³ / cm ² · second, the effect of suppressing the ink by the porous resin film and the porous fiber film is low, and the ink between the printing drum and the film is excessively extruded during printing, and the back side is extruded. Problems such as dirt and bleeding occur, and good print quality cannot be obtained if the air permeability is too small or too large.

The porous resin film 4 has a perforated area D (D ≧ 314 μm) when the thermoplastic resin film 1 is perforated.
The porosity with respect to m ² ) is (−0.0063D + 61)%
It is desirable to be within the above range. If the ratio of the component 4b of the porous resin film in the film perforated portion is large, the film perforation and the ink permeability are deteriorated, and the dot reproducibility is reduced. More preferably, the porosity (−0.0063
The ratio of the number of perforations of the film satisfying D + 61)% or more is 80% or more of the perforated portion, whereby a printed image excellent in gradation is obtained.

Printing is performed by passing ink through the perforated portion of the film by the thermal head. However, since ink cannot pass through when the cell is closed, it is preferable that the cell is not closed. However, the heat-sensitive stencil printing ink is generally a W / O-based emulsion, and this problem can be solved by the fact that a part of the porous resin film is substantially destroyed by these components and no longer forms a film.

In the formation of the cell, a substance exhibiting the above characteristics can be used by mixing it, even if it does not show the above characteristics alone. During or after formation, a means for destroying a part of the film by mechanical or chemical means may be used.
Actually, in order to manufacture the master for heat-sensitive stencil printing of the present invention, it is preferable to form a porous resin film formed by foam on a thermoplastic resin film.

In the master for stencil printing of the present invention, it is preferable that at least a part of the porous resin film remains behind the perforated portion after perforation by the thermal head. Since the porous resin film remains behind the perforated portion after perforation, the amount of transferred ink is controlled, and the back stain on the printed matter is suppressed. A schematic cross section after perforation in such a case is shown, for example, in FIG. In FIG. 4, reference numeral 1 denotes a thermoplastic resin film, 4 denotes a porous resin film, 5 denotes a heat-perforated portion of the thermoplastic resin film, 7 denotes a porous fiber film, and 8 denotes a porous film.

Plastics which are the main components of the porous resin film material include polyethylene, polypropylene, polybutene, styrene resin, polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, polyvinyl acetate, polyvinyl butyral, polyvinyl acetal, and vinyl chloride. A vinyl resin such as vinyl acetate copolymer, vinyl chloride-vinylidene chloride copolymer, vinyl chloride-acrylonitrile copolymer, styrene-acrylonitrile copolymer, etc., polyamide such as polyacrylonitrile, polyacrylic plastic, diene plastic, polybutylene, nylon, etc. Polyester, polyphenylene oxide, (meth) acrylate, polycarbonate, polyacetal, fluorine resin, polyurethane plastic Various natural plastics, natural rubber-based plastic, various thermoplastic elastomers, acetyl cellulose, acetyl butyl cellulose, and cellulose derivatives such as acetyl cellulose, etc. and microorganisms plastics, such as copolymers containing these polymers. In addition, various fatty acids, various carbohydrates such as wax, and various proteins can also be used.

In the first method for forming a porous resin film of the master for heat-sensitive stencil printing of the present invention, a resin solution is applied on the film, and the atmosphere on the coating solution is cooled by latent heat of evaporation when the solvent evaporates. This is because the coagulated poor solvent is taken into the coating liquid to form a porous resin film. That is, first, a resin solution is applied on a film and dried. At this time, the coating liquid is cooled by the heat of evaporation when the solvent volatilizes, whereby the atmosphere on the coating liquid is cooled. Due to the cooling, the poor solvent in the atmosphere condenses and is taken into the coating liquid. As a result, the poor solvent taken into the resin solution causes the resin to precipitate, whereby a porous resin film is formed.

The desired concentration of the resin film varies depending on the material used. However, if the resin concentration in the solution is too low, the porous resin film is easily broken during drying, resulting in insufficient voids or unevenness in the thickness of the porous resin film. Tends to occur. Conversely, if the resin concentration in the solution is high, it becomes difficult to take in the poor solvent into the resin solution, and it is difficult to form a porous resin film, or even if it is formed, the pore size becomes small and it is difficult to obtain desired characteristics.

The average pore size of the porous resin film becomes smaller as the portion of the film becomes closer to the film, and this tendency becomes more remarkable as the porous resin film becomes thicker, making it difficult to obtain a uniform pore size. Therefore, in order to make the pore diameter more uniform, a poor solvent for the resin may be added to the resin solution in advance. Generally, the larger the amount of the poor solvent added, the larger the diameter and the more uniform the porous resin film. However, if the addition amount of the poor solvent is excessive, the resin in the solution precipitates before the application, so that the addition amount of the poor solvent is determined within the range in which the resin does not precipitate depending on the solubility characteristics of the resin. At this time, a combination of a good solvent and a solvent that evaporates relatively easily at a lower temperature than a poor solvent is required. When one good solvent and one poor solvent are used, respectively, the boiling point of the good solvent must be relatively lower than the boiling point of the poor solvent. Selection of good and poor solvents is optional,
Generally, when the difference in boiling point is 15 to 40 ° C., a porous grease film having desired characteristics is easily formed. Boiling point difference is 10 ° C
If it is less than 1, the difference in evaporation time between the two solvents is small, and the formed film is unlikely to be porous. If the boiling point of the poor solvent is too high, drying takes a long time and the productivity is poor. Therefore, the boiling point of the poor solvent is desirably 100 ° C. or lower.

The size of the average pore size of the porous resin film is affected by the poor solvent in the atmosphere. In general, the higher the concentration, the larger the amount of coagulation and the larger the average pore size. However, the contribution to the size of the average pore diameter varies significantly depending on the amount of the poor solvent in the resin solution, and generally, the larger the amount of the poor solvent added to the resin solution, the more the effect of the concentration of the poor solvent in the atmosphere becomes. Become smaller.

In order to facilitate the formation of the porous resin film, the vapor or fine particles of the poor solvent may be sprayed onto the coating liquid on the film by a humidifier or a sprayer. By changing the particle size of the poor solvent to be sprayed, the pore size of the porous resin film can be changed. Providing a poor solvent on the film with a vaporizer, a sprayer, or the like before applying the resin liquid has the effect of reducing the number of contact points between the porous resin film and the film and improving the perforability by the thermal head.

In general, water or alcohol is often used as a poor solvent. The drying conditions must not adversely affect the film, and the drying temperature is desirably 60 ° C. or less.

Tables 1 and 2 show good solvents, poor solvents, and their boiling points for typical resins. In the table, ○ indicates a good solvent and X indicates a poor solvent. Each resin, each good solvent, and each poor solvent may be used as a mixture of two or more.

[0053]

[Table 1]

[0054]

[Table 2]

A filler may be added to the resin solution as needed. This addition affects the shape, strength, and pore size of the porous resin film formed during the drying process. Specifically, zinc oxide, titanium dioxide, calcium carbonate, inorganic compounds such as silica, polyvinyl acetate,
Organic polymer particles such as polyvinyl chloride and polymethyl acrylate. Matsumoto Yushi Pharmaceutical Co., Ltd. microcapsules and Matsumoto Microsphere can also be used effectively.

The porous resin film of the present invention has an antistatic agent, an anti-stick agent and a sticking agent as long as the effects of the present invention are not impaired.
Surfactants, preservatives, defoamers and the like can be used in combination. The formulation, application conditions, drying method, etc. of the resin solution to be applied are determined by several experiments. For coating, blade, transfer roll, wire bar, reverse roll,
Coaters of various types such as gravure and die are used.

The second method for forming a porous resin film of the master for heat-sensitive stencil printing of the present invention comprises applying a resin dissolved in a mixed solution of two or more solvents onto a thermoplastic resin film, When the resin concentration increases during the drying, the resin is precipitated to form a porous resin film. In this case, the mixed solvent is usually preferably a mixed solution of a good solvent and a poor solvent for the resin. As the ratio of the poor solvent in the mixed solvent is higher, the diameter of the voids in the formed porous resin film tends to be larger.However, when the ratio of the poor solvent is excessive, the resin in the solution before application is reduced. The ratio of the poor solvent is determined within the range in which the resin does not precipitate, depending on the solubility characteristics of the resin.

As a condition of the mixed solvent, a combination in which a good solvent is easily evaporated at a relatively low temperature with respect to a poor solvent is preferable. When one good solvent and one poor solvent are used, it is desirable that the boiling point of the good solvent is relatively lower than the boiling point of the poor solvent. The selection of a good solvent and a poor solvent is optional, but generally, when the boiling point of the good solvent is lower by 15 to 40 ° C., a porous resin film having desired characteristics is easily formed. Boiling point difference is 1
When the temperature is lower than 0 ° C., the difference between the evaporation times of the two solvents is small, and the formed film often does not easily have a porous structure. If the boiling point of the solvent is too high, drying takes a long time and the productivity is poor, so the boiling point of the solvent is desirably 100 ° C. or lower. Three or more solvents may be used. Also in this case, it is desirable that the boiling point of the main good solvent in the resin solution is lower by 15 to 40 ° C. than the boiling point of the main poor solvent.

It is necessary that drying conditions do not adversely affect the film, and the drying temperature is desirably 60 ° C. or less.
The same resin, good solvent, and poor solvent as those in the first forming method can be used.

A filler may be added to the resin solution as needed. This addition affects the shape, strength, and pore size of the porous resin film formed during the drying process. Specifically, zinc oxide, titanium dioxide, calcium carbonate, inorganic compounds such as silica, polyvinyl acetate,
Organic polymer particles such as polyvinyl chloride and polymethyl acrylate. Matsumoto Microsphere Co., Ltd.'s microcapsules and Matsumoto Microsphere can also be used effectively.

As in the case of the first forming method, an antistatic agent, an antistick agent, a surfactant, a preservative, an antifoaming agent and the like can be used in combination within a range not to impair the effects of the present invention. . The formulation, application conditions, drying method, etc. of the resin solution to be applied are determined by several experiments. For coating, various types of coaters such as a blade, a transfer roll, a wire bar, a reverse roll, a gravure, and a die are used.

As the thermoplastic resin film used in the present invention, there can be used those conventionally used as a master for heat-sensitive stencil printing, such as a vinyl chloride-vinylidene chloride copolymer film, a polypropylene film and a polyester film. The melting energy is 3-11 cal /
g of polyester film (Japanese Unexamined Patent Publication No. 62-149496).
JP-A-2-158391), a polyester film having a crystallinity of 30% or less (see JP-A-62-282883), and a polyester film containing a butylene terephthalate unit of 50 mol% or more (see JP-A-2-158391).
Polyester films that can be perforated with low energy, such as, for example, are preferred. The thickness of the film is 0.5 to 10 μm, more preferably 1.0 to 7.0 μm. If it is less than 0.5 μm, it is too thin to apply the resin liquid, and if it exceeds 10 μm, it becomes difficult to perforate with a thermal head.

In the master for heat-sensitive stencil printing of the present invention, a stick prevention layer for preventing stick with a thermal head can be provided on the surface of the film. In this case, as the stick preventing agent to be used, those generally used in conventional heat-sensitive stencil masters can be used. For example, a silicone release agent, a fluorine release agent, a phosphate ester surfactant and the like can be exemplified.

In the master for heat-sensitive stencil printing of the present invention, after the porous resin film 4 is formed on the film surface as described above, the fibrous material manufactured by a known method is formed on the surface of the porous resin film 4. Porous fiber membrane 7 formed of a substance
Are laminated. Further, a porous film 8 is laminated thereon as a reinforcing layer.

The adhesive used for laminating the porous resin film and the porous fiber film is such that if the viscosity of the adhesive is low, the adhesive enters the inside of the opening 3 of the porous resin film, and the ink permeability is low. It is preferable that the viscosity of the adhesive is so high that it does not flow into the opening of the porous resin film. Further, a high-viscosity adhesive is applied to the surface of the porous fiber membrane with a roller and laminated on the surface of the porous fiber membrane. Also,
A high-viscosity adhesive may be applied to the surface of the porous fiber membrane with a roller, and the adhesive may be dried before being laminated on the porous resin membrane surface. Alternatively, the resin liquid may be applied to the surface of the film surface, and before the resin film dries, the porous fiber film may be laminated on the resin liquid surface, dried, and the porous fiber film may be laminated on the porous resin film.

Examples of the porous fiber membrane 7 include mineral fibers such as glass, sepiolite and various metals; animal fibers such as wool and silk; plant fibers such as cotton and hemp; and regenerated fibers such as soup and rayon: polyester and polyvinyl alcohol. And synthetic fibers such as acrylic; semi-synthetic fibers such as carbon fiber; and thin paper such as inorganic fibers having a whisker structure. In this case, it is necessary to select an appropriate thickness of the fibrous substance depending on the diameter of the perforations, the thickness of the film, and the like, but the diameter is 18 μm or less, preferably 1 to 10 μm. If the diameter is smaller than 1 μm, the tensile strength is weak and lamination is difficult. If the diameter is larger than 18 μm, the passage of ink is hindered, and so-called white spots due to fibers appear on the image. The diameter of the fibrous substance may be converted into a circular diameter from denier and specific gravity. The length of the fibrous material is 0.1 to 2 m.
m is appropriate, and if it is longer than this, it becomes difficult to perform uniform dispersion.

The basis weight of the porous fiber membrane in the present invention is preferably 1 to 20 g / m ² , more preferably 3 to 10 g.
/ M ² . If the basis weight is more than 20 g / m ² , the ink permeability will be reduced and the image clarity will be reduced. In addition, basis weight is 1 g
If it is less than / m ² , sufficient strength as a support may not be obtained.

The method for producing the porous fibrous membrane composed of the fibrous substance in the present invention is not particularly limited, but it may be a paper-making paper obtained by wet-making short fibers, a non-woven fabric or a woven fabric, or a screen. A gauze or the like may be used, and papermaking paper can be preferably used in terms of productivity and cost.

Examples of the porous membrane 8 include mineral fibers such as glass, sepiolite and various metals; animal fibers such as wool and silk; plant fibers such as cotton and hemp; regenerated fibers such as soup and rayon; polyester and polyvinyl alcohol; Synthetic fiber such as acrylic: semi-synthetic fiber such as carbon fiber: tissue paper such as inorganic fiber having a whisker structure. In this case, the thickness of the fibrous material is 14 μm in diameter.
The thickness is preferably 21 μm or more.

Further, a mesh screen or a porous sheet may be used as the porous film 8. Alternatively, it may be formed by gravure, offset, flexographic printing, or the like, or nozzle coating.

JP-A-10-147075 discloses a master for heat-sensitive stencil printing in which one layer of a porous fiber film is laminated on a porous resin film. In the case of a porous fiber membrane having a strength for satisfying the printing property, the fiber diameter becomes large, which affects a printed image. Therefore, it is necessary to provide as thin a fiber as possible on the surface in contact with the porous resin film. But,
When the basis weight of the fine fiber is increased to improve the strength, the ink permeability is deteriorated and the image rise is deteriorated.

Therefore, in the present invention, the porous fiber membrane 7 having a small fiber diameter is used on the porous resin membrane, and the fiber diameter is large and the tensile strength is high as compared with the porous fiber membrane. A porous film 8 is provided as a reinforcing layer. Furthermore, if the space of the porous film 8 is made larger than the space of the porous fiber film, the ink diffusibility is improved, and the effect of the thick fibers of the porous film 8 and the like does not appear on the image.

In the above example, a single-layer porous film 8 is used, but a plurality of porous films 8 may be used. In this case, dispersibility of the ink is improved by increasing the gap in the upper layer.

In the heat-sensitive stencil master of the present invention, when a plurality of layers of a porous support made of a fibrous substance are not laminated on the outermost surface, the tensile strength is low, and the heat-sensitive stencil master during printing is weak. Elongation and breakage easily occur.

Further, since the porous resin film 7 exists between the film and the porous film 8 having relatively large diameters and volumes of constituent elements (for example, fibers), the fibers and the like overlap and the adhesive is accumulated, There is no hindrance to perforation by the thermal head. Further, since the ink is uniformly dispersed in the porous resin film, printing unevenness due to the overlapping of fibers does not occur.

[0076]

Next, the present invention will be described specifically with reference to examples and comparative examples, but the present invention is not limited to these examples. Parts here are by weight.

(Example 1) Cellulose acetate butyrate (softening point 131 ° C.) 5 parts (Eastman Kodak Co., Ltd. CAB381-20) Methyl ethyl ketone (boiling point 79.6 ° C.) 85 parts Water (boiling point 100.0 ° C.) 5 parts Methyl alcohol (boiling point: 64.5 ° C) 5 parts The solution having the above composition was stirred and dissolved.
In a 0 ° C., 50% RH atmosphere, a wire bar (0.6 mm) was placed on a 3.5 μm-thick biaxially stretched polyester film.
Diameter). This was left as it was for 1 minute, and then left in a 50 ° C. drying box for 2 minutes and dried to form a porous resin film 4 on the film 1.
The surface state of the porous resin film 4 is schematically shown in FIG. On the surface of the film 1 opposite to the surface where the porous resin film 4 is formed, in order to prevent the hot-melted film from sticking to the thermal head, and for the purpose of preventing static electricity,
A mixture of a silicone resin and a cationic antistatic agent was applied so as to have an adhesion amount of about 0.05 g / m ² after drying. Subsequently, 1 part of vinyl chloride / vinyl acetate copolymer (VYHH, manufactured by Union Carbide Co.) 0.8 parts of polyester fiber (0.15 denier, manufactured by Teijin Limited, 4 μm in diameter with a specific gravity of 1.4) 8 parts of ethyl acetate The mixture consisting of
A porous fiber membrane 7 was prepared by coating the polyester film of μm with a roll coater to a dry adhesion amount of 3.5 g / m ² . The drying temperature was 50 ° C. The obtained porous fiber membrane 7 is peeled off from the polyester film, a polyethylene-based adhesive is applied to the porous fiber membrane 7 at 3 g / m ² , the surface thereof is laminated on the porous resin membrane 4, and the porous Stencil printing machine Preport VT3820 as conductive film
A polyethylene-based adhesive was applied at 3 g / m ² to a support of a master (VT II master) specified by Ricoh Co., Ltd., to obtain a master for stencil printing of the present invention.

(Example 2) Cellulose acetate butyrate (softening point 131 ° C.) 5 parts Methyl ethyl ketone (boiling point 79.6 ° C.) 60 parts Water (boiling point 100.0 ° C.) 30 parts Methyl alcohol (boiling point 64.5 ° C.) 5 parts A porous resin film, a porous fiber film, and a porous film were formed under the same conditions as in Example 1 to obtain a master for stencil printing of the present invention.

(Example 3) Cellulose acetate butyrate (softening point 131 ° C.) 5 parts Methyl ethyl ketone (boiling point 79.6 ° C.) 85 parts Water (boiling point 100.0 ° C.) 5 parts Methyl alcohol (boiling point 64.5 ° C.) 5 Part Stir and dissolve the liquid with the above composition, leave it to stand and sufficiently defoam,
A wire bar (0.6 mm) was placed on a 3.5 μm-thick biaxially stretched polyester film in an atmosphere of 30 ° C. and 50% RH.
Diameter) and humidifier (HITACHI)
Humidifier UV-107D) to 10c
The particles of water were contacted for 15 seconds at a distance of m. This was left for 1 minute, then left in a 50 ° C. drying box for 2 minutes and dried to form a porous resin film on the film. Further, a porous fiber film and a porous film were formed in the same manner as in Example 1. It was laminated on a porous resin film. A mixture of a silicone resin and a cationic antistatic agent was applied to the surface of the film opposite to where the porous resin film was formed, in the same manner as in Example 1.
A master for heat-sensitive stencil printing of the present invention was obtained.

(Comparative Example 1) Cellulose acetate butyrate (softening point: 131 ° C.) 15 parts Methyl ethyl ketone (boiling point: 79.6 ° C.) 85 parts A liquid having the above composition was stirred and dissolved.
A wire bar (0.15 mm) was placed on a 3.5 μm thick biaxially oriented polyester film in a 0 ° C., 60% RH atmosphere.
Diameter). This was left as it was for 1 minute, and then left in a drying box at 50 ° C. for 2 minutes to be dried, thereby forming a porous resin film on the film. It was laminated to the membrane. In the same manner as in Example 1, a mixture of a silicone resin and a cationic antistatic agent was applied to the surface of the film opposite to the surface on which the porous resin film was formed, to obtain a master for heat-sensitive stencil printing of a comparative example.

(Example 4) Vinyl chloride vinyl acetate copolymer (softening point 78 ° C.) 3 parts (VYHH manufactured by Union Carbide) Acetone (boiling point 56.1 ° C.) 20 parts Ethyl alcohol (boiling point 78.3 ° C.) 8 parts Stir and dissolve the liquid of the composition, leave it still and defoam sufficiently,
A wire bar (1.0 m) was placed on a 3.5 μm thick biaxially stretched polyester film in a 20 ° C., 50% RH atmosphere.
m diameter). Put this in a 50 ° C drying box for 2
After leaving it to dry for a minute, a porous resin film was formed on the film. The surface state of the porous resin film 4 is as follows:
This is shown schematically in FIG. Further, a porous fiber membrane and a porous membrane were laminated on a porous resin membrane in the same manner as in Example 1. On the side opposite to the one where the porous resin film of the film was formed,
In the same manner as in Example 1, a mixture of a silicone resin and a cationic antistatic agent was applied to obtain a master for heat-sensitive stencil printing of the present invention.

Example 5 A porous resin film was produced under the same conditions as in Example 4 except that a 1.5 μm-thick biaxially stretched polyester film was used instead of the 3.5 μm-thick biaxially stretched polyester film. And a porous fiber membrane and a porous membrane were formed to obtain a master for stencil printing of the present invention.

(Example 6) Vinyl chloride-vinyl acetate copolymer (softening point: 83 ° C.) 3 parts (VAGD manufactured by Union Carbide) Methyl ethyl ketone (boiling point: 79.6 ° C.) 17 parts Methyl alcohol (boiling point: 64.5 ° C.) 9 parts A porous resin film, and a porous fiber film and a porous film were formed under the same conditions as in Example 4 to obtain a master for thermosensitive stencil printing of the present invention.

(Example 7) Cellulose acetate butyrate (softening point: 131 ° C.) 3 parts Acetone (boiling point: 56.1 ° C.) 18 parts Water (boiling point: 100 ° C.) 5 parts Silica powder 0.3 part Same as Example 4 above Under the conditions, a porous resin film, a porous fiber film and a porous film were formed to obtain a master for stencil printing of the present invention.

Comparative Example 2 Acrylic acid-styrene copolymer (softening point 47 ° C.) 16 parts (O / W emulsion resin component 43%) (J840 manufactured by Johnson Polymer Co.) Water (boiling point 100.0 ° C.) 33 parts Silica powder 3 parts After uniformly dispersing the liquid having the above composition disclosed in JP-A-4-7198, a porous resin film and a porous fiber film were formed under the same conditions as in Example 4 above, and A master for heat-sensitive stencil printing was obtained.

(Example 8) Polyvinyl butyral (softening point: 87 ° C.) 8 parts (PVB3000-2 manufactured by Denki Kagaku Kogyo Co., Ltd.) Ethyl alcohol (boiling point: 78.3 ° C.) 69 parts Water (boiling point: 100.0 ° C.) 23 parts Acrylic Acid-styrene copolymer (softening point 65 ° C.) 1.2 parts (J679 manufactured by Johnson Polymer Co.) After stirring and dissolving the liquid having the above composition, titanium oxide (rutile)
1.6 parts were added, and this was dispersed in a ball mill for 1 hour. After the dispersion, a porous resin film, and a porous fiber film and a porous film were formed under the same conditions as in Example 4 to obtain a master for heat-sensitive stencil printing of the present invention.

(Comparative Example 3) A silicone resin and a cationic resin were applied to one surface of the biaxially stretched polyester film having a thickness of 3.5 μm used in Examples 1 to 4, 6, and 7 and Comparative Examples 1 and 2 in the same manner as in Example 1. The mixture of the system antistatic agent was applied so that the adhesion amount after drying was about 0.05 g / m ² , to obtain a master for heat-sensitive stencil printing.

Comparative Example 4 A mixture of a silicone resin and a cationic antistatic agent was applied to one surface of a biaxially stretched polyester film having a thickness of 7.0 μm in the same manner as in Example 1 to obtain an adhesion amount after drying of about 0.05 g / m ² simmer manner was applied to obtain a heat-sensitive stencil master.

Comparative Example 5 In the same manner as in Example 2, only a porous resin film was formed, and a master for heat-sensitive stencil printing was obtained.

Comparative Example 6 A porous resin film and a porous film (without the porous fiber film 7) were formed in the same manner as in Example 2.

<Evaluation> The softening point of the resin, the average pore diameter of the porous resin film,
The area ratios 1 and 2, and the strength of the stiffness were measured by the following methods, and the strength, perforation sensitivity, image quality, and back stain were measured by a stencil printing machine Preport VT3820 manufactured by Ricoh Co., Ltd. and its ink (VT
60011, lot no. 960604-22) and evaluated according to the following criteria. Prepress printing is 20
In a 60 ° C., 60% RH environment, the application pulse width was set to be longer than the 7% standard state, and the printing speed was set to 3 speeds. Table 3 shows the results.

(A) Softening point of resin Measured by using a thermal stress / strain measuring device TMA / SS150C (manufactured by Seiko Instruments Inc.).

(B) Using a tracing paper to mark the holes in the surface photograph of the electron microscope photographed at an average pore diameter of 1000 times the porous resin film, LA-555 was used.
D (manufactured by Beers Co., Ltd.), image processing was performed, and each hole diameter was converted to a perfect circle, and the average value was obtained.

(C) Area ratio 1 The area ratio 1 is such that the diameter when each hole diameter is converted into a perfect circle is 5 μm.
The ratio of the total opening area of the above holes to the total surface area of the porous resin film. The holes in the surface photograph of the electron microscope taken at a magnification of 1000 times are marked using tracing paper, and LA-555D [(stock) ) Made by Bias), and each hole diameter was determined by converting it to a perfect circle.

(D) Area ratio 2 Area ratio 2 is the ratio of the total opening area of the holes having a diameter of 5 μm or more in terms of a perfect circle to the total opening area of the porous resin film, and was taken at a magnification of 1000 times. The hole of the electron microscope surface photograph was marked using tracing paper, and LA-5
Image processing was carried out using 55D (manufactured by Beers Co., Ltd.), and each hole diameter was determined by converting it to a perfect circle.

(E) Strength of stiffness Measured with a Lorentzen Stiffness tester.

(V) Strength: A sample in which the porous resin film and the porous fiber film were not peeled off when run by the thermal head was indicated by ◎, and a sample in which the film was slightly peeled was indicated by ○.

(G) Perforation sensitivity: A film where the film portion of the master is perforated by the thermal head in a completely normal manner is indicated by ◎; a film which is perforated but has a partially reduced perforation diameter is ○; a film which is not partially perforated. Δ, those that were hardly perforated were indicated by x.

(H) Image quality The printed image was observed with the naked eye, and bleeding, blurring and uneven density were superior to the current master [Ricoh VTII Master Co., Ltd.].
Those which are inferior to the current master are indicated by x.

(I) Back stains The printed matter was observed with the naked eye, and the current master [Ricoh V Co., Ltd.
TII master] is indicated by 現行, those equivalent to the current master are indicated by ○, and those inferior to the current master are indicated by ×.

(D) Image Density The image density of the printed matter was measured with an RD914 densitometer manufactured by Macbeth, and the measured value was shown.

(G) Print elongation After printing 3000 sheets, no master elongation was indicated by ◎, and elongation was indicated by x.

[0103]

[Table 3]

Example 8 Polyvinyl butyral (softening point: 87 ° C.) 4 parts (PVB3000-2 manufactured by Denki Kagaku Kogyo Co., Ltd.) Ethyl alcohol 35.5 parts Water 11.5 parts Acicular magnesium silicate 0.8 parts (Mizusawa Chemical (Corporation, Adeplus SP) Polyvinyl butyral resin was dissolved in a mixed solution of ethyl alcohol and water, and then acicular magnesium silicate was added, followed by sufficient dispersion and mixing with a ball mill. The solution was filtered to obtain a coating solution.
This coating solution was uniformly applied to a 3.5 μm-thick biaxially stretched polyester film by a wire bar coating method.
Immediately after the application, the film was dried in hot air at 50 ° C. for 3 minutes to form a porous resin film on the polyester film, and a porous fiber film was formed in the same manner as in Example 1. Laminated. In the same manner as in Example 1, a mixture of a silicone resin and a cationic antistatic agent was applied to the surface of the film opposite to where the porous resin film was formed, to obtain a master for heat-sensitive stencil printing of the present invention. Wire diameter 0.6mm,
Using a wire bar of 0.8 mm, 1.0 mm, 1.2 mm, and 1.4 mm, samples were prepared in which the amount of the porous resin film attached was changed. Here, the area ratio 1 was 35 to 43%. The air permeability of the support having a porous resin membrane and a porous fiber membrane is 62 cm ³ / cm ² · sec, respectively.
53cm ³ / cm ² · second, 57cm ³ / cm ² · second, 48c
At m ³ / cm ² · sec and 39 cm ³ / cm ² · sec, a sufficient image density without set-off was obtained at a stiffness of 65 mN.
FIG. 7 shows the relationship between the stiffness and the image density.

The air permeability was measured using a stencil printer Preport VT3820 (product of Ricoh Co., Ltd.) at 10 cm × 1.
A solid chart of 0 cm is read, and a perforation corresponding to the solid is made on the sample.
er (air permeability tester; product of Toyo Seiki Seisaku-sho, Ltd.). The film surface opening area ratio is obtained by taking an enlarged photograph of the film surface with an optical microscope (100 times magnification),
Then, an enlarged copy (200%) was made with a plain paper copier Imagio MF530 (manufactured by Ricoh Co., Ltd.). An OHP film was weighed on the copy, and an opening was marked on the OHP film. Read the marked OHP film with a scanner (300 DPI, 256 gradations), image retouching software, Adobe Photoshop
It was binarized using op2.5J. Thereafter, the image area ratio of the marked opening was measured by using image analysis freeware software NIH image.

Example 9 Polyvinyl butyral (softening point: 87 ° C.) 4 parts (PVB3000-2 manufactured by Denki Kagaku Kogyo Co., Ltd.) Ethyl alcohol 35.5 parts Water 11.5 parts Same as Example 4 with the above formulation A porous resin film and a porous fiber film were formed. In the same manner as in Example 1, a mixture of a silicone resin and a cationic antistatic agent was applied to the surface of the film opposite to the surface on which the porous resin film was formed, to obtain a master for heat-sensitive stencil printing of the present invention. Here, the area ratio 1 is 33 to 40
%Met. The air permeability of the support having the porous resin membrane and the porous fiber membrane is 60 cm ³ / cm ² · sec, 31
cm ³ / cm ² · second, 26 cm ³ / cm ² · second, 21 cm ³
/ Cm ² · second and 17 cm ³ / cm ² · second. FIG. 7 shows the relationship between the stiffness and the image density. As can be seen from FIG. 7, the image density of the master for heat-sensitive stencil printing of the present invention to which a filler has been added hardly changes even when the stiffness increases. However, in this example in which no filler was added, the image density decreased as the stiffness increased. This was because the air permeability of the support composed of the porous resin membrane and the porous fiber membrane was reduced, and the flow of the ink was reduced.

(Example 10) Polyvinyl acetal 2 parts Ethyl alcohol 18 parts Water 13 parts Plate-like magnesium silicate (talc) 0.4 part (Micro Ace P4 manufactured by Nippon Talc Co., Ltd.) In a resin solution of polyvinyl acetal, plate-like magnesium silicate was added. Was added and dispersed and mixed in a ball mill. Thickness 1.
Example 4 on a 5 μm biaxially stretched polyester film
In the same manner as described above, a uniform coating was performed using a wire bar. Immediately after the application, the film was dried in hot air at 50 ° C. for 3 minutes to form a porous resin film. Thereafter, a porous fiber membrane was further prepared in the same manner as in Example 1, and this was laminated on a porous resin membrane. Example 1 on the surface opposite to the surface where the porous resin film of the film was formed
Similarly to the above, a mixture of a silicone resin and a cationic antistatic agent was applied to obtain a master for heat-sensitive stencil printing of the present invention. Here, the area ratio 1 was 65 to 76%. The air permeability of the support having the porous resin membrane and the porous textile membrane is 54 cm ³ / cm ² · second, 60 cm ³ / cm ² · second, respectively.
56cm ³ / cm ² · second, 46cm ³ / cm ² · second, 37c
FIG. 7 shows the relationship between stiffness and image density in m ³ / cm ² · second.
Indicated as

Example 11 Polyvinyl acetal 2 parts Ethyl alcohol 18 parts Water 13 parts A porous resin film and a porous fiber film were produced in the same manner as in Example 6. In the same manner as in Example 1, a mixture of a silicone resin and a cationic antistatic agent was applied to the surface of the film opposite to the surface on which the porous resin film was formed, to obtain a master for heat-sensitive stencil printing of the present invention. Here, the area ratio 1 was 61 to 72%.
The air permeability of the support having the porous resin membrane and the porous fiber membrane is 54 cm ³ / cm ² · sec and 39 cm ³ / c, respectively.
m ² · second, 28 cm ³ / cm ² · second, 19 cm ³ / cm ² ·
Seconds, 12 cm ³ / cm ² · sec, decreased as the strength of stiffness increased. FIG. 7 shows the relationship between the stiffness and the image density. It can be seen that the image density is high even when the strength of the stiffness is increased by the addition of the plate-like magnesium silicate. However, in this example in which no filler is added, the image density sharply decreases as the stiffness increases. This phenomenon indicates that the area ratio 1 is low and the porous resin film is not sufficiently formed.

(Example 12) Polycarbonate 2 parts Polyvinyl butyral 1.1 parts Tetrahydrofuran 28 parts Ethyl alcohol 3.8 parts Potassium titanate whisker 0.4 part (Tofica Y, manufactured by Otsuka Chemical Co., Ltd.) Dissolved in the mixed solution, further added polyvinyl butyral as an adhesion improving material for the porous resin film and the thermoplastic resin film, added potassium titanate-based whisker to the dissolved resin solution, thoroughly dispersed and mixed with a ball mill, and applied. And
A 1.0 mm wire bar was used to uniformly coat a 3.5 μm thick biaxially stretched film to form a porous resin film. Thereafter, a porous fiber membrane was further prepared in the same manner as in Example 1, and this was laminated on a porous resin membrane. In the same manner as in Example 1, a mixture of a silicone resin and a cationic antistatic agent was applied to the surface of the film opposite to where the porous resin film was formed, to obtain a master for heat-sensitive stencil printing of the present invention.
The area ratio 1 was 44%, and the air permeability of the support having the porous resin film and the porous fiber film was 142 cm ³ / cm ² · second. There is little set-off of printed matter, and the strength of stiffness is 10mN,
A master for thermosensitive stencil printing having a density of 1.05 at the time of image was obtained.

Example 13 The atmosphere for coating a porous resin film on a film was 23 ° C., 30% RH and 23 ° C., 9 ° C.
A master for heat-sensitive stencil printing of the present invention was obtained in the same manner as in Example 8 except that the RH was 0% RH.

(Examples 14 to 19) Polyvinyl acetal resin (manufactured by Sekisui Chemical Co., Ltd., Eslek KS-1) 3.2 parts Talc (manufactured by Nippon Talc, Microace LG) 2.4 parts Sorbitan fatty acid ester ( Nikko Chemicals, SO-10) 0.1 part Modified silicone oil (KF6012, Shin-Etsu Chemical Co., Ltd.) 0.1 part Acrylic polymer O / W emulsion (Joncryl-711, Johnson Polymer) 0.2 part The above was dissolved and dispersed in ethyl acetate, and added to water (HEC
(1% solution) was slowly added with stirring to obtain a coating liquid for forming a cloudy porous resin film. Ethyl acetate and water (HEC
The amount of the (1% solution) depends on the solid content concentration (SC) of each coating solution shown in Table 4, and the ratio between the two is 1.5 for ethyl acetate and 1.0 for water (HEC 1% solution). . Each of the above coating solutions was applied on a 2.0 μm-thick biaxially stretched polyester film by a die head in an atmosphere of 20 ° C. and 50% RH so that the adhesion amount after drying became the value shown in Table 4. ° C
Drying was performed in a 50% RH atmosphere to form a porous resin film.
After the formation of the porous resin film, a porous fiber film and a porous film were laminated on the porous resin film in the same manner as in Example 1.

Formulation of anti-fusing agent coating liquid Silicone oil (SF8422 manufactured by Shin-Etsu Chemical Co., Ltd.) 0.5 part Surfactant (Plysurf A208 manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) 0.5 part Toluene 100.0 parts The anti-fusing agent coating solution is applied to the surface of the thermoplastic resin film opposite to the porous resin film by using a bar coater so that the adhesion amount after drying is about 0.05 g / m ² , A stencil master was obtained.

The masters of Examples 14 to 19 obtained above were used as stencil printing machine Preport JP1300 JP5050.
Perform plate making and printing with VT6000, and
The image after printing was examined. In addition, Table 4 and FIG. 8 show the evaluations of the thermosensitive stencil master. In the print image of Table 4,
は indicates good, Δ indicates slight white spots, and × indicates bad. As shown in FIG. 8, the porosity of the porous resin film is (−
0.0063D + 61)% or more (however, perforated area 31
In the case of 4 μm ² ), good results were obtained for the printed image.

<Evaluation> (E) Porous resin film void area ratio The porous resin film of the master was placed on the film side with an optical microscope (Olympus BX60, magnification 20; Olympus BX60 magnification).
0 times. Lighting is reflected light, level 9. The polarizing filter is used at the position where the sharpness is most effective. ) Observe and capture images into a computer. Focus on the surface of the porous resin film. (The sample is brought closer to the eyepiece of the optical microscope, and the part of the porous resin film that is focused first)
The image is binarized using the image processing software “WinROOF” (manufactured by Mitani Corporation) to determine the void area ratio.
The binarization procedure is as follows. Gray image conversion, density conversion (default), automatic binarization (P tile method, default), filling in holes, deletion (100 or less), measurement (shape feature-
area). In the case of a master in which a porous fiber membrane is laminated on a porous resin membrane, in the step of creating the master,
Before laminating the porous fiber membrane, take a photograph from the side without the film.

(W) Film perforated area The film perforated area of the master was observed with an optical microscope (Olympus, Olympus BX60 magnification: 200 times, reflected light, level 9. Use a polarizing filter at the position where sharpness is most effective). Capture images to computer.
The image is binarized using the image processing software “WinROOF” (manufactured by Mitani Corporation) to determine the void area ratio.
The binarization procedure is as follows. Gray image conversion, density conversion (default), automatic binarization (P tile method, default), filling in, deletion (500 or less), measurement (shape feature-
area).

[0116]

[Table 4]

[0117]

According to the first to fifth aspects of the present invention, there is provided a master for heat-sensitive stencil printing capable of obtaining high-quality images having high stiffness and tensile strength. In addition, since the porous fiber film made of the fiber having a high tensile strength is laminated on the upper surface of the porous resin film having a relatively low tensile strength, the elongation at the time of printing of the master can be prevented. Furthermore, since a porous resin film exists between the film and the porous fiber film made of a fibrous substance, the fibers overlap and the adhesive accumulates, and there is no hindrance to perforation by the thermal head. Since the ink is uniformly dispersed in the film, a master for heat-sensitive stencil printing which does not cause printing unevenness due to overlapping of fibers can be obtained. According to the sixth aspect of the present invention, there is provided a stencil printing method in which the amount of ink transferred is controlled by the porous resin film remaining behind the perforated portion after perforation and the back stain on the printed material is suppressed. According to the invention of claim 7, by using a heat-sensitive stencil master capable of obtaining high-quality image with high stiffness and tensile strength,
A stencil printing apparatus capable of performing high-quality printing with little set-off and preventing elongation during printing is provided.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view of an example of a master for heat-sensitive stencil printing of the present invention.

FIG. 2 is a schematic sectional view of another example of the master for heat-sensitive stencil printing of the present invention.

FIG. 3 is a schematic cross-sectional view of another example of the master for heat-sensitive stencil printing of the present invention.

FIG. 4 is a schematic sectional view of a heat-sensitive stencil master in which at least a part of a porous resin film remains behind a perforated portion after perforation by a thermal head.

FIG. 5 is a diagram showing a surface state of a porous resin film of Example 1.

FIG. 6 is a view showing a surface state of a porous resin film of Example 4.

FIG. 7 is a diagram showing the relationship between the stiffness of a support having a porous resin membrane and a porous textile membrane and image density.

FIG. 8 is a diagram showing a relationship between a perforated area of a thermoplastic resin film and a porosity of a porous resin film.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Thermoplastic resin film 3 Porous resin film opening 4 Porous resin film 4b Constituent elements constituting porous resin film 4 7 Porous textile film 8 Porous film

Claims (7)

[Claims] Claims: 1. On one surface of a thermoplastic resin film,
A stencil master for heat-sensitive stencil printing, wherein a porous resin film and a porous fiber film made of a fibrous substance are sequentially laminated, and a porous film is further laminated on the laminated film. 2. The range of the porosity of the porous resin film in contact with the perforated area D of the thermoplastic resin film is not less than (−0.0063D + 61)% (where D ≧ 3).
^{2. The} master for heat-sensitive stencil printing according to claim 1, wherein the thickness of the master is 14 μm ² ). 3. The porous resin film according to claim 1, wherein the total opening area of the holes having a diameter of 5 μm or more in terms of perfect circle is in the range of 4 to 80% of the total surface area. 3. The master for heat-sensitive stencil printing according to 2. 4. The porous resin film according to claim 1, wherein the total opening area of the holes having a diameter of 5 μm or more when converted into a perfect circle is 50% or more of the total opening area on the surface of the porous resin film. The master for heat-sensitive stencil printing according to any one of the above. 5. When the thermoplastic resin film is perforated such that the film surface has an opening area ratio of 20% or more, a value measured by a gas permeability tester is 1.0 to 157.
The master for heat-sensitive stencil printing according to any one of claims 1 to 4, wherein the temperature is in the range of cm ³ / cm ² · second. 6. Using the master for heat-sensitive stencil printing according to any one of claims 1 to 5, performing perforation by a thermal head so that at least a part of the porous resin film remains behind the perforated portion after perforation. Characterized stencil printing method. 7. A plate making apparatus for performing plate making by heat-melting and perforating the master for heat-sensitive stencil printing according to claim 1, a plate cylinder around which the master for heat-sensitive stencil printing formed is wound. An ink replenishment mechanism provided inside the plate cylinder, and a pressing device for pressing a printing sheet against the thermosensitive stencil master wound around the outer peripheral surface of the plate cylinder. Stencil printing device.