JP2007276488A - Master for thermal perforated printing and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a printing master for thermal perforated form printing having a support body which strengthens a tensile strength of the master, prevents an elongation of the master in printing to prevent expiring, is strong in a firm to have a support body for improving perforation sensitiveness, and is free from irregularity in printing with small ink sticking amount and little in back soiling of prints and to provide its manufacturing method. <P>SOLUTION: A porous resin film 4 comprising resin is provided on one side surface of a thermoplastic resin film 1. Further, the master for thermal perforated form printing comprising by making a porous fiber film 7 consisting of a fibrous material overlie its surface, and its manufacturing method. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a heat-sensitive stencil printing master and a method for producing the same, and more particularly to a structure of a support provided in contact with a thermoplastic resin film and a method for producing the same.

  A thermoplastic thin film (hereinafter sometimes simply referred to as “film”) is bonded with a porous thin paper as an ink permeable support (hereinafter sometimes simply referred to as “support”) with an adhesive, and the film surface is adhered to the surface. There is known a heat-sensitive stencil printing master provided with a stick prevention layer for stick prevention with a thermal head. In practice, a heat-sensitive stencil master with a sticky adhesive layer on the film surface and a sticky layer on the film surface is widely used as a porous thin paper with hemp fibers or a mixture of hemp fibers and synthetic fibers and wood fibers. It has been.

  However, in such a conventional heat-sensitive stencil master, since there is a support made of fibers on the upper surface of the film, (1) a large amount of adhesive is placed on the portion where the fibers overlap and the portion where the film contacts, In that portion, drilling by the thermal head becomes difficult. In addition, problems remain such that the portion prevents the passage of ink and causes uneven printing, and (2) the fiber itself prevents the passage of ink and causes uneven printing.

  In consideration of these points, several heat-sensitive stencil masters have been proposed. For example, Patent Document 1 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, but the problem (2) remains. Patent Document 2 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, flexo or the like. However, with the current printing technology, it is difficult to print a pattern with a line width of 50 μm or less, and even if it can be done, productivity is poor and expensive. Moreover, generally, when the line width is 30 μm or more, the heat-resistant resin prevents perforation by the thermal head, and printing unevenness occurs. Further, Patent Document 3 discloses that a heat-sensitive stencil printing master is manufactured by applying a liquid mixture of fine particles such as a water-dispersible polymer and colloidal silica to a film surface and drying to form a porous layer. A method of making a plate using [Riso Kagaku Kogyo Co., Ltd.] and printing using EPSON, HG-4800 ink (for ink jet method) is disclosed, but the porous layer obtained by this method is printed The ink does not pass well, and conventional heat-sensitive stencil inks are not practical because a sufficient density cannot be obtained during printing. Further, this layer itself does not have a sufficient heat insulating effect, and the film has poor perforation properties.

However, Patent Document 4 discloses a printing master that is substantially composed of only a film without using a support. According to this, the problems (1) and (2) are solved, On the other hand, it creates new problems. One of them is that when the film has a thickness of 10 μm or less, its “stiffness” is weak and the conveyance becomes difficult. As a solution to this problem, Patent Document 5 proposes the idea that the film is wound around the plate cylinder peripheral wall of the printing machine without being cut, and the entire film rotates with the rotation of the plate cylinder during printing. Has been. However, in this method, since the film and the loading / unloading plate unit rotate with the rotation of the plate cylinder during printing, the moment of rotation increases, and the displacement from the rotation axis of the center of gravity is large. It must be heavy and big. In addition, when the film has a thickness of 5 μm or more, its thermal sensitivity is low, and it is difficult to perforate with a thermal head. Furthermore, the rate at which the energy applied from the heating means is lost to the platen through the master increases, so that less energy is used for drilling, and drilling is difficult.
Japanese Patent Laid-Open No. 3-193445 Japanese Patent Laid-Open No. 62-198459 Japanese Patent Laid-Open No. 4-7198 JP 54-33117 A Japanese Patent Publication No. 5-70595

  The present invention has been made in view of the above-described prior art, and a first object is to provide a support that increases the tensile strength of the master and prevents elongation and breakage of the master during printing. An object of the present invention is to provide a heat-sensitive stencil master and a method for producing the same. Another object of the present invention is to provide a thermosensitive stencil printing master having a support that strengthens the stiffness of a thermoplastic resin film and improves the perforation sensitivity of the film by a heat insulating effect, and a method for producing the same. . A third object is to provide a heat-sensitive stencil printing master with a small amount of ink adhesion, no printing unevenness, and a small amount of back stain on the printed matter, and a method for producing the same.

  As a result of studying the master for heat-sensitive stencil printing from various angles, the present inventors have (i) a support made of only a fibrous substance that prevents ink from passing and prevents perforation by a thermal head. Preferably, it should be absent. (B) If the support is free of fibrous material, the master has a low tensile strength and generates print elongation. (C) The support is preferably a relatively small contact with the film. It is desirable that the material does not impede the passage of ink and gives sufficient stiffness and tensile strength for conveyance on a printing press, and (d) the support made of fibrous material has high tensile strength. From the research results, the master for thermal stencil printing has a porous resin film made of resin on one surface of the film and a porous fiber film made of fibrous material on the surface thereof. I was sure that better. The present invention has been made thereby.

  The “porous resin film” referred to here is a porous film formed by precipitating and condensing a resin dissolved in a solvent. If the film is compared with a floor on the film, a cell having a large number of ceilings in FIG. 5 or a wall-like film made up of an assembly of cells without a ceiling in FIG. 5, a foam-like film made up of an aggregate of open-celled cells in FIG. 2, and a particle-like or fibrous resin in FIG. It means a film formed by a formed aggregated film or the like. In addition, the porous fiber membrane means a membrane formed of thin paper made of fiber materials such as plant fibers such as cotton and hemp, synthetic fibers such as polyester and polyvinyl alcohol. 1 to 3 and FIG. 5, 1 is a thermoplastic resin film, 4 is a porous resin film, 4a is a wall-like film in a cell constituting the porous resin film, and 4b is a porous resin film. And 7 are porous fiber membranes.

  According to the present invention, (1) having a porous resin film made of a resin on one surface of a thermoplastic resin film, and further laminating a porous fiber film made of a fibrous material on the surface, A master for heat-sensitive stencil printing, characterized in that the total opening area of holes having a diameter when converted to a perfect circle of 5 μm or more on the surface of the porous resin film is 50% or more of the total opening area, (2) above (1 ) In which the constituent elements of the porous resin film are bonded to each other, (3) In the above (1) or (2), at least a part of the porous resin film (4) In the above (1), (2) or (3), a part of the porous resin film affects the influence of printing ink, wherein the master has a softening temperature of 150 ° C. or less. To be no longer filmy Thermal stencil printing master according to symptoms, is provided.

  Furthermore, according to the present invention, as a means for preparing the heat-sensitive stencil printing master of (1), (2), (3) or (4), (5) a porous resin film formed by foam is heated. A method for producing a master for heat-sensitive stencil printing, characterized in that a porous fiber film made of a fibrous material is laminated on the surface of a plastic resin film, and (6) a fluid object containing foam is thermoplastic. A method for producing a master for heat-sensitive stencil printing, which is coated on a resin film, dried, and further laminated with a porous fiber film made of a fibrous material on the surface thereof, (7) a substance that generates foam Heat-sensitive stencil printing characterized in that a fluid composition is applied on a thermoplastic resin film, gas is generated during or after application, and a porous fiber film made of a fibrous material is laminated on the surface. For master (8) A fluid composition containing at least one of two or more components that generate gas when in contact with each other is coated on a thermoplastic resin film and the coated surface contains other components. A method for producing a master for heat-sensitive stencil printing, which comprises coating, foaming, forming a film, and further laminating a porous fiber film made of a fibrous material on the surface thereof; (9) under a pressure higher than 1 atm. A master for heat-sensitive stencil printing, characterized in that a flowable composition in which gas is dissolved is applied to a thermoplastic resin film under normal pressure, foamed, and a porous fiber film made of a fibrous material is laminated on the surface. A manufacturing method is provided.

  According to the present invention, (10) a porous resin film is provided on one surface of the thermoplastic resin film, and the surface of the porous resin film has pores with a diameter of 5 μm or more when converted into a perfect circle. The total opening area is in the range of 4 to 80% of the total surface area, and further, a porous fiber film made of a fibrous material is laminated on the surface, and the diameter when converted into a perfect circle on the surface of the porous resin film (11) at least a part of the porous resin film has a softening temperature of 150 ° C. or lower, wherein the total opening area of holes having a diameter of 5 μm or more is 50% or more of the total opening area; A heat-sensitive stencil printing master as described in (10) above, (12) a heat-sensitive stencil printing master as described in (10) above having a bending stiffness of 5 mN or more, (13) Thermal There is provided the heat-sensitive stencil printing master described in (10) above, wherein at least part of the porous resin film remains behind the perforated part after the film is perforated by the head.

  Furthermore, according to the present invention, as a means for preparing the heat-sensitive stencil printing master of (10), (11), (12) or (13), (14) an organic solvent resin solution is formed on the thermoplastic resin film. It is characterized in that it is applied, and then a poor solvent vapor or fine particles of the resin is brought into contact with the application surface to form a porous resin film, and a porous fiber film made of a fibrous material is laminated on the surface. (15) A method for producing a heat-sensitive stencil master as described in (14) above, wherein the poor solvent is water, and (16) a mixture of two or more solvents. The resin dissolved in the liquid is applied onto the thermoplastic resin film, and the resin concentration is increased during the drying to precipitate the resin, thereby forming a porous resin film, and further to the surface of the fibrous substance Porous fiber membrane made of (17) The above-mentioned (14), (15) or (16), wherein the organic solvent resin solution contains water or a hydrophilic solvent. A method for producing a heat-sensitive stencil master described in 1) is provided.

Further, according to the present invention, (18) the thermoplastic resin film has a porous resin film on one surface and a porous fiber film made of a fibrous material on the surface, and the thermoplastic resin film surface has an open area. When the perforation is performed at a rate of 20% or more, the measured value in the air permeability tester is in the range of 1.0 cm ³ / cm ² · sec to 157 cm ³ / cm ² · sec, and the surface of the porous resin film The master for heat-sensitive stencil printing, wherein the total opening area of holes having a diameter of 5 μm or more when converted into a perfect circle is 50% or more of the total opening area, (19) The bending stiffness is 5 mN or more There is provided a heat-sensitive stencil printing master described in (18) above.

  Furthermore, according to the present invention, (20) a resin dissolved in a mixed solution of two or more solvents is applied onto a thermoplastic resin film, and the resin concentration is increased during the drying, thereby increasing the resin concentration. In order to obtain a heat-sensitive stencil printing master by depositing a porous resin film and further laminating a porous fiber film made of a fibrous material on the surface, the resin solution temperature to be applied is 10 ° C. to 30 ° C. And the manufacturing atmosphere of the master for thermosensitive stencil printing characterized by the application atmosphere being 10 to 30 degreeC and 50% RH or less is provided.

  Still further, according to the present invention, (21) the above-mentioned (1) is characterized in that, when perforated by a thermal head, two or more and seven or less of the fibrous material crosses per hole. A master for heat-sensitive stencil printing according to (10) or (18) is provided.

  According to the first, second, fifth, sixth, seventh, eighth and ninth aspects of the present invention, a heat-sensitive stencil printing master capable of obtaining a high quality image with strong stiffness and tensile strength is obtained. Further, since the porous fiber film made of fibers having a high tensile strength is laminated on the upper surface of the porous resin film having a relatively low tensile strength, elongation during 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 is accumulated, and there is no inhibition of perforation by the thermal head. In addition, since the ink is uniformly dispersed by the porous resin film, uneven printing due to the overlap of fibers does not occur.

  According to the third and fourth aspects of the invention, in addition to the above effects, a heat-sensitive stencil printing master capable of effectively performing perforation with a thermal head is obtained.

  Furthermore, according to the inventions of claims 10 to 22, in addition to the above-mentioned effects, not only a heat-sensitive stencil printing master with less back contamination can be obtained, but also the production method has the above-described configuration, so that it can be used under mild conditions. In addition, since the heat-sensitive stencil master of the present invention can be obtained stably by a simple operation, the industrial value is extremely high.

  Hereinafter, the present invention will be described in more detail. A schematic cross section of a master for heat-sensitive stencil printing provided with a support having the porous resin film and the porous fiber film of the present invention is shown, for example, in FIG. In FIG. 6, 4 is a porous resin film, 3 is a porous resin film opening, 1 is a thermoplastic resin film, and 7 is a porous fiber film.

  As described above, the “porous resin film” in the present invention is a film in which an aggregate of cells with a ceiling or an aggregate of cells without a ceiling is formed when the film is compared to a floor.

  The cell may be closed or a part thereof may be open. Opening can be achieved, for example, by breaking the foam film during the drying process. The broken line in FIG. 1 and the inside of the donut shape in FIG. 4 represent the opening. FIG. 5 shows an open state. The angle formed by the wall-like film 4a in the cell constituting the film 1 and the porous resin film 4 in the vicinity of contacting the thermoplastic resin film 1, that is, the rising angle θ of the wall-like film 4a from the film 1 is 20 degrees or more. Desirably, it is more desirably 30 degrees or more, and the upper limit is 90 degrees. These porous resin films 4 are constituted by an assembly of the cells. 1, 2, 4, and 5, the cells 4 b constituting the porous resin film 4 are bonded to each other.

  The average pore diameter of the porous resin film 4 is generally 1 μm or more and 50 μm or less, preferably 2 μm or more and 30 μm or less. When 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 passing, the side of the printing drum or the side of the printing drum is wound during printing. The printing ink oozes out from the trailing edge of the master. Further, the porosity in the porous resin film is often lowered, and perforation by the thermal head is likely to be hindered. When the average pore diameter exceeds 50 μm, the ink suppression effect due to the porous resin film becomes low, the ink between the printing drum and the film is excessively pushed out during printing, and problems such as back stains and smearing occur. If the pore diameter 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 have a continuous structure in the thickness direction in the porous film from the viewpoint of ink permeability. In addition, when the film is used as a floor, it is desirable that the film penetrates in the ceiling direction. 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 perforation by the thermal head is not hindered. The thickness of the resin constituting the porous resin film 4 covering the film 1 that does not hinder perforation by the thermal head varies depending on the type of resin constituting the film, the thermal sensitivity of the film, etc., but generally combined with the film The thickness is 7 μm or less.

  On the surface of the porous resin film, the total opening area of 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. When the ratio is less than 4%, perforation by the thermal head and ink passage are likely to be hindered. The porous resin film 4 has a completely different structure from the porous portion of the conventional thermal stencil printing master. The solid part forming the structure consists of an irregularly shaped rod-like, spherical, and branched aggregate assembly, and what kind of structure is obtained depends on the production conditions of the resin film, for example, the type of resin, the solid content concentration of the liquid Depending on the type of solvent, the amount of the resin liquid attached, the resin liquid drying temperature, the coating atmosphere temperature, the humidity, etc.

  In particular, the influence of the resin liquid temperature, the coating atmosphere temperature, and the humidity is great. When the temperature of the resin liquid is 10 ° C. or less, the resin liquid of the present invention is easily gelled and difficult to apply the solution. Conversely, when the temperature exceeds 30 ° C., it becomes difficult to form a porous resin film. Accordingly, the coating atmosphere temperature is preferably 10 ° C. or higher and 30 ° C. or lower. Further, when the humidity of the atmosphere exceeds 50% RH, the amount of moisture adsorbed on the film surface increases, and as a result, the wettability with the coating solution decreases, so that the adhesion between the porous resin film and the film is inferior. Become.

  The master for thermal stencil printing using the support having the porous resin film 4 and the porous fiber film 7 of the present invention is a stencil printing machine preport VT3820 (manufactured by Ricoh Co., Ltd.) and its ink (VT600 II, When the plate width is set to 20% and 60% RH (printing speed: 3) and the applied pulse width is set longer than the standard state by 7% using lot no. Concentration is 0.7 to 1.3, preferably 0.9 to 1.25 (measured with a RD914 densitometer manufactured by Macbeth)], and the structure of the porous resin film 4 of the present invention is special. This is clearly different from that of Kaihei 4-7198. When the ink for an ink jet system is used for the heat-sensitive stencil printing master of the present invention, the ink transfer amount becomes too large, blurring occurs, and a clear image cannot be obtained.

  The viscosity of VT600 II ink (lot no. 960604-22) was 150 poise at 20 ° C. when measured with a viscometer HAAKE CV20 using a rotor PK30-4.0 at a share rate of 20 (1 / S). It was.

  Similarly, on the surface of the porous resin film, the total opening area of holes having a diameter of 5 μm or more when converted into a perfect circle is 50% or more, preferably 70% or more of the total opening area. When the ratio is less than 50%, perforation by the thermal head and ink passage are likely to be hindered.

  The thickness of the porous resin film 4 as a support is 5 μm or more and 100 μm or less, preferably 6 μm or more and 50 μm or less. 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 part after perforation by the thermal head. Cheap. Further, the effect of suppressing the ink transfer amount of the porous resin film 4 is larger as the film is thicker, and the amount of ink transferred onto the printing paper during printing can be adjusted by the thickness of the porous resin film 4. When the thickness after coating is larger than the target, it can be reduced to the target thickness by means such as calendering with a calendar. Thickness measurements are made with virtually no load or very little load.

  When the average pore diameter of the porous resin film 4 is 20 μm or less, the thicker the porous resin film layer is, the more difficult it is for the printing ink to pass. Therefore, the amount of ink transferred to the printing paper can be controlled by the thickness of this layer. . If the thickness of the layer is not uniform, uneven printing may occur. Therefore, it is desirable that the thickness is uniform. Thickness measurements are made with virtually no load or very little load.

Adhesion amount as a support for the porous resin membrane, 0.5~25g / m ^2, preferably ^{2g / m 2 ~15g / m 2} , in particular 2~7g / m ² is desirable. Adhesion amount of increase will degrade the image quality prevent passage of ink, difficult to obtain a sufficient film strength is less than 0.5 g / m ^2, conversely, prevents the passage of ink exceeds 25 g / m ² quality Make it worse.

The density of the porous resin film 4 is usually 0.01 g / cm ³ or more and 1 g / cm ³ or less, preferably 0.1 g / cm ³ or more and 0.5 g / cm ³ or less. 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. On the other hand, if the density exceeds 1 g / cm ³ , the passage of ink is hindered and the image quality is deteriorated.

  The stiffness of the heat-sensitive stencil printing master of the present invention is desirably a bending stiffness of 5 mN or more (by Lorenzen Stiffness Tester). When the bending stiffness is less than 5 mN, it may be difficult to transport the heat-sensitive stencil master on a printing machine.

In the present invention, when the thermoplastic resin film surface of the master for heat-sensitive stencil printing is perforated so that the opening area ratio is 20% or more, the measured value with a breathability tester is 1.0 cm ³ / cm ² · sec. The range is 157 cm ³ / cm ² · sec. Here, the aperture area ratio is the total area of the through-holes on the film surface of the thermal stencil printing master when the thermal stencil printing master is subjected to solid plate making with a thermal head, laser, flash lamp, etc. The ratio of the solid portion per unit area.

  If the opening area ratio is less than 20%, it is necessary to use an ink having a very low viscosity in order to ensure the image density. In such an ink, the uniformity of the solid portion or the fine line in the stencil printing system is required. Reproducibility is not good.

In this case, if the air permeability is less than 1.0 cm ³ / cm ² · sec, the ink permeability is poor, and if low-viscosity ink is used in order to obtain a sufficient amount of ink passage, image bleeding or printing may occur. A phenomenon occurs in which printing ink oozes out from the side of the printing drum or the rear end of the wound master. In addition, the porosity in the porous resin film and the porous fiber film is often lowered, and perforation by the thermal head is likely to be hindered. When the air permeability exceeds 157 cm ³ / cm ² · sec, the ink suppression effect by the porous resin film and the porous fiber film is reduced, and the ink between the printing drum and the film is excessively pushed out during printing. Problems such as dirt and smearing occur, and good print quality cannot be obtained if the air permeability is too small or too large.

  The porous resin film is desirably softened at a temperature of 150 ° C. or lower in at least a part thereof, that is, a part of the porous resin film in contact with the film, in order to make the film perforation by the thermal head more effective. In order to adjust the pore diameter, shape, strength, stiffness, etc. of the membrane, a porous resin membrane containing a pigment is preferable.

  In addition, printing is performed by passing the ink through the perforated portion of the film by the thermal head, but the ink cannot pass when the cell is closed. However, the heat-sensitive stencil printing ink is generally a W / O emulsion, and this problem can be solved by partially destroying the porous resin film with these components so that it does not become a film. It is desirable that the cell is not closed.

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

  Plastics that are the main component of the porous resin film material include polyethylene, polypropylene, polybutene, styrene resin, polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, polyvinyl acetate, polyvinyl butyral, polyvinyl acetal, vinyl chloride Vinyl-based resins such as vinyl acetate copolymer, vinyl chloride-vinylidene chloride copolymer, vinyl chloride-acrylonitrile copolymer, styrene-acrylonitrile copolymer, polyacrylonitrile, polyacrylic plastic, diene plastic, polybutylene, polyamide such as nylon, polyester , Polyphenylene oxide, (meth) acrylic acid ester, polycarbonate, polyacetal, fluorine resin, polyurethane plastic, various natural Plastic, natural rubber-based plastic, various thermoplastic elastomer - and the like -, acetyl cellulose, acetyl butyl cellulose, and cellulose derivatives such as acetyl cellulose, etc. and microorganisms plastics, copolymers containing these polymers. In addition, various carbohydrates such as various fatty acids and waxes, and various proteins can also be used.

  In order to form a porous resin film, (1) a fluid composition containing foam, (2) a fluid composition containing one of two or more components that generate gas when in contact with each other, Alternatively, (3) a fluid composition in which a gas is dissolved under a pressure higher than 1 atm is used. To this, the following components are added in addition to the porous resin film material.

(I) As a liquid viscosity improver, CMC, polyvinyl alcohol, glycerin, glycols sodium alginate and the like.
(Ii) Solventless, solvent-based (dissolved, dispersed), aqueous (dissolved, dispersed), emulsion-based, etc.
(Iii) Powders, pigments, fluids with low volatility, etc. may be included to improve foam stability, facilitate film formation, increase strength, and change properties. As the powder and pigment, various organic and inorganic powders are used. Fats and oils, oils, plasticizers, activators, and the like are used as the less volatile fluid.
(Iv) An anionic, cationic, zwitterionic or nonionic surfactant is used as a surfactant for improving foaming properties. Among these, an anionic system is preferable in terms of foamability. Higher alcohols such as higher alcohol sulfates are particularly excellent in terms of foamability and foam stability. In the case of an aqueous system, the amount added to water is 0.001 to 0.1% by weight. Egg white, saponin, gelatin and the like also improve foam stability.

  In addition, the heat-sensitive stencil printing master of the present invention is preferably such that at least a part of the porous resin film remains behind the perforated part after perforation by the thermal head. By leaving a porous resin film behind the perforated part after perforation, the amount of ink transfer is controlled, and the back stain of the printed matter is suppressed. Therefore, a schematic cross section after drilling by the thermal head of the master for thermal stencil printing of the present invention is shown in FIG. 7, for example. In FIG. 7, 1 is a thermoplastic resin film, 4 is a porous resin film, 5 is a thermoplastic resin film heat perforated part, and 7 is a porous fiber film.

In order to form a porous resin film composed of foam, the following method is employed.
(1) To the liquid such as water, the substance that forms the porous resin film, a surfactant, and the like are added, and stirred, foamed, coated, and dried with an agitator, a mixer, or the like. In addition to stirring, a chemical reaction can be used as a foaming means. For example, it is applied and dried before bubbles disappear, such as the reaction of sodium hydrogen carbonate with acid such as succinic acid, the reaction of aluminum sulfate with sodium hydrogen carbonate. The formulation of the coating liquid, the stirring conditions, etc. are determined by several experiments. For coating, various types of coaters such as air doctor, blade, truss farol, rod, reverse roll, gravure, die, notch bar, fountain, etc. are used. As drying conditions, it is necessary not to adversely affect the thermoplastic resin film, and the drying temperature is preferably 60 ° C. or less.

(2) For example, wax, polyethylene glycol or the like that exhibits fluidity at about 50 ° C. to 60 ° C. is foamed and then cooled and hardened after coating.

(3) Applying a composition fluid containing a foaming agent that generates gases such as nitrogen, carbon dioxide, water vapor, oxygen, and hydrogen by energy, and generating gas by energy such as heat, light, electromagnetic waves, radiation, and electricity , Solidify the foam part. In this case, foaming may be performed after forming the porous resin film. The capsules contained in the fluid may be dissolved or shattered by the action of heat or other energy, and a gas may be generated by chemical or physical action. A capsule swelled by heat or the like may be used as the foam. Carbon dioxide generated by vaporization of dry ice, nitrogen generated by applying light to a diazo compound, and the like can also be used.

(4) At least one of the two or more components that generate gas when in contact with each other may be processed into a film, and a liquid containing the remaining components may be applied to generate gas. For example, an aqueous solution containing sodium bicarbonate and a small amount of a substance having a film forming function such as CMC, polyvinyl alcohol, gelatin, sodium alginate, etc. is applied to the film, dried, and then succinic acid, aluminum sulfate and porous A liquid containing a conductive resin film forming material or the like is applied thereon to generate carbon dioxide bubbles, and dried to form a desired porous resin film.

(5) A gas such as air is dissolved in the liquid under high pressure, and then foamed by applying the film to the film under normal pressure, followed by drying to form the desired porous resin film.

(6) In addition, ink must pass through the support (porous resin film and porous fiber film) for printing, but the porous resin film by foam covers the film in a hemispherical shape. If there are not enough holes for ink to pass through, holes for ink to pass through are formed by rubbing the surface on which the film is formed. This operation is performed, for example, on a winding unit of a coating machine or on a slitter.

  The first method for forming the porous resin film of the master for heat-sensitive stencil printing of the present invention is that the resin solution is applied onto the film, and the atmosphere on the coating liquid is cooled and condensed by the latent heat of vaporization when the solvent volatilizes. This is because a 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, thereby cooling the atmosphere on the coating liquid. By being cooled, the poor solvent in the atmosphere is condensed and taken into the coating liquid. As a result, the poor solvent taken into the resin solution causes the resin to precipitate, thereby forming a porous resin film.

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

  The average pore diameter of the porous resin film becomes smaller as the film is closer to the film, and this tendency becomes more prominent as the porous resin film is thicker, making it difficult to obtain a uniform pore diameter. 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 porous resin film is formed. However, when the addition amount of the poor solvent is excessive, the resin in the solution is precipitated before coating, and therefore, the addition amount of the poor solvent is determined within a range in which the resin does not precipitate depending on the dissolution characteristics of the resin. At this time, the good solvent needs to be a combination that is relatively easy to evaporate at a lower temperature than the poor solvent. When one good solvent and one poor solvent are used, the boiling point of the good solvent must be relatively lower than the boiling point of the poor solvent. The selection of the good solvent and the poor solvent is arbitrary, but in general, a porous resin film having desired characteristics is easily formed when the difference in boiling points is 15 to 40 ° C. When the difference in boiling points is less than 10 ° C., the difference in evaporation time between the two solvents is small, and the formed film is unlikely to have a porous structure. When the boiling point of the poor solvent is too high, drying takes time and the productivity is poor, so the boiling point of the poor solvent is desirably 100 ° C. or lower.

  The size of the average pore diameter of the porous resin film is affected by the poor solvent in the atmosphere. Generally, the higher the concentration, the larger the amount of condensation and the larger the average pore diameter. However, the contribution ratio to the average pore size varies significantly depending on the amount of the poor solvent in the resin liquid. Generally, the greater the amount of the poor solvent added to the resin liquid, the more the influence of the concentration of the poor solvent in the atmosphere. Get smaller.

  In order to facilitate the formation of the porous resin film, a vapor or fine particles of a poor solvent may be sprayed onto the coating solution on the film by a humidifier or a spray. By changing the particle size of the poor solvent to be sprayed, the pore size of the porous resin film can be changed. Applying a poor solvent to the film by a vaporizer, a spraying device, or the like before application of the resin solution has the effect of reducing the contact between the porous resin film and the film and improving the piercing property by the thermal head.

  In general, water or alcohol is often used as a poor solvent. As drying conditions, it is necessary not to adversely affect the film, and the drying temperature is preferably 60 ° C. or lower.

  Tables 1 and 2 show good solvents, poor solvents, and boiling points of typical resins. In the table, ◯ represents a good solvent and x represents a poor solvent.

  Each resin may be used in combination of two or more. Two or more good solvents and poor solvents may be used. A filler may be added to the resin solution as necessary. This addition affects the shape, strength, and pore size of the porous resin film produced during the drying process. Specific examples include inorganic compounds such as zinc oxide, titanium dioxide, calcium carbonate, and silica, and organic polymer particles such as polyvinyl acetate, polyvinyl chloride, and polymethyl acrylate. Matsumoto Yushi Seiyaku Co., Ltd.'s microcapsules and Matsumoto Microsphere can also be used effectively.

  The porous resin film of the present invention can be used in combination with an antistatic agent, an anti-stick agent, a surfactant, an antiseptic, an antifoaming agent and the like within a range that does not impair the effects of the present invention. The formulation of the resin liquid to be applied, the application conditions, the drying method, etc. are determined by several experiments. For coating, various types of coaters such as blades, transfer rolls, wire bars, reverse rolls, gravure, and dies are used.

  In the second method of forming the porous resin film of the master for heat-sensitive stencil printing of the present invention, a resin dissolved in a mixed liquid of two or more solvents is applied on a thermoplastic resin film and is being dried. When the resin concentration is increased, the resin is deposited 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. The higher the proportion of the poor solvent in the mixed solvent, the larger the void diameter of the formed porous resin film tends to be seen. However, when the proportion of the poor solvent is excessive, the resin in the solution is reduced before coating. Since it precipitates, the proportion of the poor solvent is determined within the range where the resin does not precipitate, depending on the dissolution characteristics of the resin.

  As a condition for the mixed solvent, a combination in which the good solvent easily evaporates at a low temperature relative to the 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 that of the poor solvent. The selection of the good solvent and the poor solvent is arbitrary, but in general, when the boiling point of the good solvent is 15 to 40 ° C., a porous resin film having desired characteristics is easily formed. When the difference in boiling points is less than 10 ° C., the difference in evaporation time between the two solvents is small, and the formed film often has a porous structure. When the boiling point of the solvent is too high, drying takes 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 15 to 40 ° C. lower than the boiling point of the main poor solvent.

  As drying conditions, it is necessary not to adversely affect the film, and the drying temperature is preferably 60 ° C. or lower. The same resin as the first production method can be used as the resin, good solvent, and poor solvent.

  Each resin may be used in combination of two or more. A filler may be added to the resin solution as necessary. This addition affects the shape, strength, and pore size of the porous resin film produced during the drying process. Specific examples include inorganic compounds such as zinc oxide, titanium dioxide, calcium carbonate, and silica, and organic polymer particles such as polyvinyl acetate, polyvinyl chloride, and polymethyl acrylate. Matsumoto Yushi Seiyaku Co., Ltd.'s microcapsules and Matsumoto Microsphere can also be used effectively.

  As in the case of the first production method, the porous resin film of the present invention has an antistatic agent, an anti-stick agent, a surfactant, a preservative, an antifoaming agent and the like within a range not inhibiting the effects of the present invention. Etc. can be used together. The formulation of the resin liquid to be applied, the application conditions, the drying method, etc. are determined by several experiments. For coating, various types of coaters such as blades, transfer rolls, wire bars, reverse rolls, gravure, and dies are used.

  As the thermoplastic resin film used in the present invention, those conventionally used for heat-sensitive stencil printing masters such as vinyl chloride-vinylidene chloride copolymer film, polypropylene film, and polyester film can be used. Is a polyester film having a crystallinity of 30% or less (see JP 62-282893), and a butylene terephthalate unit of 50 mol% or more. A polyester film that can be perforated with low energy such as a polyester film (see JP-A-2-158391) is preferable. 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 is 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 sticking with the thermal head can be provided on the surface of the film. In this case, as the anti-sticking agent used, those generally used in conventional heat-sensitive stencil masters can be used. For example, silicone release agents, fluorine release agents, phosphate ester surfactants and the like can be exemplified.

  In the heat-sensitive stencil printing master of the present invention, the porous resin film 4 is formed on the film surface as described above, and then formed on the surface of the porous resin film 4 with a fibrous material produced by a known method. The formed porous fiber membrane 7 is laminated. Since the adhesive used when laminating the porous resin film and the porous fiber film has a low viscosity of the adhesive, the adhesive penetrates into the opening 3 of the porous resin film, and the ink permeability becomes poor. The viscosity of the adhesive is preferably as high as not to 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. Alternatively, a high-viscosity adhesive may be applied to the surface of the porous fiber membrane with a roller and laminated on the surface of the porous resin film after the adhesive has dried. Alternatively, the resin liquid may be applied to the surface of the film, and the porous fiber film may be laminated on the surface of the resin liquid before the resin film is dried, and dried, and the porous fiber film may be laminated on the porous resin film. In the heat-sensitive stencil printing master of the present invention, when a porous support made of a fibrous material is not laminated on the outermost surface, the tensile strength is weak and the heat-sensitive stencil printing master is stretched or cut during printing. It becomes easy to do.

  7 porous fiber membranes include mineral fibers such as glass, sepiolite and various metals: animal fibers such as wool and silk: plant fibers such as cotton and linen: regenerated fibers such as sufu and rayon: polyester, polyvinyl alcohol, acrylic Synthetic fibers such as: Semi-synthetic fibers such as carbon fiber: Thin paper such as inorganic fibers having a whisker structure. The thickness of the fibrous material in this case needs to be selected appropriately depending on the perforation diameter, the thickness of the film, etc., but the diameter is 20 μm or less, preferably 1 to 10 μm. If the diameter is smaller than 1 μm, the tensile strength is weak, and if it is larger than 20 μm, the passage of ink is hindered, and so-called white spots due to fibers appear in the image. The diameter of the fibrous material may be converted into a circular diameter from denier and specific gravity. The length of the fibrous material is suitably 0.1 to 2 mm, and if it is longer than this, it becomes difficult to uniformly disperse.

  In the heat-sensitive stencil printing master of the present invention, in the relationship between the film and the fibrous material, when the film is perforated with a thermal head, 2 to 7 fibrous materials are crossed for each hole. More preferably. If there are less than two fibrous materials crossing the perforated part, the effect of preventing the ink from passing is small and the effect of preventing the set-off is small, and if it is more than seven, the effect of preventing the ink from passing becomes too large and the printed image becomes faint. Trouble occurs. The ratio of the number of perforations traversed by 2 or more and 7 or less of the fibrous material is desirably 80% or more of the perforated portion, and is determined by 100 perforations randomly selected from a micrograph. If even a part of the fibrous material is perforated, it is determined as one.

  In the present invention, since the porous fiber film made of fibers having a high tensile strength is laminated on the upper surface of the porous resin film having a relatively low tensile strength, elongation during printing of the master can be prevented. In addition, since a porous resin film exists between the film and the support made of fibers, the fibers overlap and the adhesive accumulates, and there is no inhibition of perforation by the thermal head. Further, since the ink is uniformly dispersed by the porous resin film, uneven printing due to the overlap of fibers does not occur.

  Next, the present invention will be specifically described with reference to examples and comparative examples. The parts here are based on weight.

Examples 1-5
A biaxially stretched polyester having a thickness of 2 μm was used as the film. The liquid of the formulation shown in Table 3 was foamed using a homomixer, and the foam was coated on the film using an air knife coater and dried at 50 ° C. to 60 ° C. (Examples 1 to 4). In Example 5, foaming foam was applied and dried without using a homomixer. The amount of adhesion after drying was ² to 7 g / m ² . In Table 3, the numerical values indicate the number of copies.

In Examples 1 to 5,
1 part of vinyl chloride / vinyl acetate copolymer (VYHH, manufactured by Union Carbide)
2 parts of polyester fiber (manufactured by Teijin Limited, 0.15 denier, specific gravity of 1.4 μm in diameter)
A mixture of 8 parts of ethyl acetate was well dispersed with a ball mill, and applied to a polyester film having a thickness of 1.5 μm using a roll coater to a dry adhesion amount of 3.5 g / m ² to prepare a porous fiber membrane 7. did. The drying temperature was 50 ° C. The obtained porous fiber film 7 was peeled from the polyester film, 3 g / m ² of polyethylene adhesive was applied to the porous fiber film 7, and the surface was laminated to the porous resin film 4.

Further, on the opposite surface of the film, a mixture of a silicone resin and a cationic antistatic agent is applied to prevent the hot melted film from sticking to the thermal head and for the purpose of antistatic. The coating was performed so as to be 0.05 g / m ² . The strength of the stiffness was measured with a Lorenz Stiffness Tester. Further, the transportability and the image (unevenness of printing) were tested with a stencil printer Preport VT-1730 manufactured by Ricoh and its ink. The evaluation results are summarized in Table 4.

Comparative Example 1
A thermoplastic resin film stretched 1.5 times or more in both longitudinal and lateral directions and having a thickness of 20 μm or less (the stretched polyethylene, polypropylene, polyvinyl chloride, vinyl chloride disclosed in JP-A-54-33117) Vinylidene chloride copolymer, polystyrene, polyester, nylon, etc.) were used as a master for thermal stencil printing, and were subjected to plate making printing in the same manner as in Example 1.

Comparative Example 2
Example 1 A mixture of natural hemp (abaca) fibers and synthetic fibers was used as a support, and a stretched thermoplastic resin film having a thickness of 0.5 to 5 μm was bonded thereto to be used as a master for heat-sensitive stencil printing. In the same manner as above, it was subjected to plate making printing.

Comparative Example 3
Only the porous resin film was formed on the polyester film in the same manner as in Example 1 to obtain a heat-sensitive stencil printing master.

  Table 4 summarizes the evaluation results of the heat-sensitive stencil printing masters of these examples and comparative examples.

* Here, “good” image quality (printing unevenness) means that there is no fiber texture. Also, “good” print elongation means that there is almost no elongation of the master.

Example 6
Cellulose acetate butyrate (softening point 131 ° C) 5 parts (CAB381-20 manufactured by Eastman Kodak Company)
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 In a 50 ° RH atmosphere at 50 ° C., a uniform coating was applied with a wire bar (0.6 mm diameter) on a 3.5 μm thick biaxially stretched polyester film. The porous resin film 4 was formed on the film 1 by leaving it as it was for 1 minute and then allowing it to stand for 2 minutes in a 50 ° C. drying box and drying it. The surface state of the porous resin film 4 is schematically shown in FIG. A mixture of a silicone resin and a cationic antistatic agent for preventing the thermally melted film from sticking to the thermal head on the opposite side of the film 1 from which the porous resin film 4 is formed and for the purpose of antistatic. Was applied so that the adhesion amount after drying was about 0.05 g / m ² , and a porous fiber membrane 7 was prepared in the same manner as in Example 1, and this was laminated to the porous resin membrane 4. A heat-sensitive stencil printing master of the present invention was obtained.

Example 7
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 Same conditions as in Example 6 above A porous resin film and a porous fiber film were formed by heating to obtain a heat-sensitive stencil printing master of the present invention.

Example 8
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 parts After standing still and defoaming sufficiently, in a 30 ° C., 50% RH atmosphere, uniformly apply to a 3.5 μm-thick biaxially stretched polyester film with a wire bar (0.6 mm diameter). Were contacted with fine water particles for 15 seconds at a distance of 10 cm from a humidifier (HITACHI Humidifier UV-107D). This was left for 1 minute, then left in a 50 ° C. drying box for 2 minutes to dry, thereby forming a porous resin film on the film. Further, a porous fiber film was prepared in the same manner as in Example 1, Was laminated to a porous resin film. In the same manner as in Example 6, a mixture of a silicone resin and a cationic antistatic agent was applied to the opposite side of the film on which the porous resin film was formed to obtain a heat-sensitive stencil printing master of the present invention.

Comparative Example 4
Cellulose acetate butyrate (softening point 131 ° C.) 15 parts Methyl ethyl ketone (boiling point 79.6 ° C.) 85 parts The solution of the above composition is dissolved with stirring, left to stand and thoroughly defoamed, and then in an atmosphere of 20 ° C. and 60% RH, It applied uniformly with the wire bar (0.15 mm diameter) on the 3.5 micrometer-thick biaxially stretched polyester film. This was left as it was for 1 minute, then left in a 50 ° C. drying box for 2 minutes to dry, thereby forming a porous resin film on the film, and further creating a porous fiber film in the same manner as in Example 1, It was laminated to a porous resin film. In the same manner as in Example 6, a mixture of a silicone resin and a cationic antistatic agent was applied to the opposite side of the film on which the porous resin film was formed to obtain a heat-sensitive stencil printing master of Comparative Example.

Example 9
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 The solution of the above composition was stirred and dissolved, allowed to stand and thoroughly defoamed, then at 20 ° C. in a 50% RH atmosphere, It apply | coated uniformly with the wire bar (1.0-mm diameter) on the 3.5-micrometer-thick biaxial stretching polyester film. This was allowed to stand for 2 minutes in a 50 ° C. drying box and dried to form a porous resin film on the film. The surface state of the porous resin film 4 is schematically shown in FIG. Further, a porous fiber membrane was prepared in the same manner as in Example 1, and was laminated on the porous resin membrane. In the same manner as in Example 6, a mixture of a silicone resin and a cationic antistatic agent was applied to the opposite side of the film on which the porous resin film was formed to obtain a heat-sensitive stencil printing master of the present invention.

Example 10
A porous resin film and a porous fiber film were formed under the same conditions as in Example 9 except that a 1.5 μm thick biaxially stretched polyester film was used instead of the 3.5 μm thick biaxially stretched polyester film. The master for heat-sensitive stencil printing of the present invention was obtained.

Example 11
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 are formed under the same conditions as in Example 9 above, and for thermal stencil printing of the present invention Got the master.

Example 12
Cellulose acetate butyrate (softening point 131 ° C.) 3 parts Acetone (boiling point 56.1 ° C.) 20 parts Water (boiling point 100.0 ° C.) 5 parts Silica powder 0.3 part Porous resin under the same conditions as in Example 9 above A film and a porous fiber film were formed to obtain a heat-sensitive stencil printing master of the present invention.

Comparative Example 5
Acrylic styrene copolymer (softening point 47 ° C) 16 parts (O / W emulsion resin component 43%)
(J840 manufactured by Johnson Polymer Co., Ltd.)
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 under the same conditions as in Example 9 above And the porous fiber membrane was formed and the master for heat-sensitive stencil printing of a comparative example was obtained.

Example 13
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., Ltd.)
After stirring and dissolving the liquid having the above composition, 1.6 parts of titanium oxide (rutile) is added and dispersed in a ball mill for 1 hour. After dispersion, a porous resin film and a porous fiber film were formed under the same conditions as in Example 9 to obtain a heat-sensitive stencil printing master of the present invention.

Comparative Example 6
On one side of the 3.5 μm thick biaxially stretched polyester film used in Examples 6 to 9, 11, 12 and Comparative Examples 4 and 5, a mixture of a silicone resin and a cationic antistatic agent was applied in the same manner as in Example 6. It was applied so that the adhesion amount after drying was about 0.05 g / m ² to obtain a heat-sensitive stencil master.

Comparative Example 7
A mixture of a silicone resin and a cationic antistatic agent was applied to one side of a 7.0 μm-thick biaxially stretched polyester film in the same manner as in Example 6 so that the adhesion amount after drying was about 0.05 g / m ^2. A heat-sensitive stencil printing master was obtained.

Comparative Example 8
In the same manner as in Example 7, only a porous resin film was formed to obtain a heat-sensitive stencil printing master.

Comparative Example 9
Instead of the porous fiber membrane of Example 7, a support of a stencil printing machine preport VT3820 (manufactured by Ricoh Co., Ltd.) designated master (VT II master) was used.

<Evaluation>
About the heat-sensitive stencil printing master obtained above, the softening point of the resin, the average pore diameter of the porous resin film, the area ratios 1 and 2, and the stiffness were measured by the following methods, and the strength, perforation sensitivity, image quality, The stain was tested using Ricoh Co., Ltd. stencil printer Preport VT3820 and its ink (VT600 II, lot no. 960604-22), and evaluated according to the following criteria. Plate-making printing was performed at a printing speed of 3 speeds in an environment of 20 ° C. and 60% RH with an applied pulse width set longer than 7% standard state. However, only in Example 10, the applied pulse width was evaluated in the standard state. The results are shown in Table 5.

(A) Softening point of resin It was measured using a thermal stress strain measuring device TMA / SS150C (manufactured by Seiko Denshi Kogyo Co., Ltd.).

(B) Porous resin film average pore diameter The hole part of the electron microscope surface photograph image | photographed by 1000 time is marked using a tracing paper, and image processing is carried out using LA-555D [made by Pierce Co., Ltd.], and each pore diameter Was converted into a perfect circle and used as the average value.

(C) Area ratio 1
The area ratio 1 is the ratio of the total opening area of pores having a diameter of 5 μm or more when each pore diameter is converted to a perfect circle to the total surface area of the porous resin film. The hole was marked using tracing paper, and image processing was performed using LA-555D [manufactured by Pierce Co., Ltd.], and each hole diameter was determined by converting into a perfect circle.

(D) Area ratio 2
The area ratio 2 is the ratio of the total opening area of pores with a diameter of 5 μm or more when converted into a perfect circle to the total opening area of the porous resin film. It marked using the racing paper, image-processed using LA-555D [made by Pierce Co., Ltd.], and calculated | required each hole diameter by converting into a perfect circle.

(E) Strength of stiffness Measured with a Lorenz Stiffness Tester.

(F) Strength The case where the porous resin film and the porous fiber film were not peeled when running with a thermal head was indicated by ◎, and the case where the porous film was slightly peeled was indicated by ◯.

(G) Perforation sensitivity ◎ if the film part of the master is completely perforated by the thermal head, 、, perforated but partly smaller in perforation diameter ○, most not perforated △, almost Those which are not perforated are indicated by ×.

(H) Image quality Observe the printed image with the naked eye, ◎ the blurring, blurring, density unevenness is better than the current master [Ricoh VT II Master] ◎, the same as the current master ○, from the current master Inferior ones are indicated by x.

(Ri) Back dirt Observe the printed material with the naked eye, and indicate that it is better than the current master [Ricoh VT II Master], ○ that is equivalent to the current master, and × that is inferior to the current master. It was.

(Nu) Image density The image density of the printed material was measured with a RD914 densitometer manufactured by Macbeth, and the measured value was shown.

(L) Printing elongation After 1000 sheets of printing were completed, no elongation of the master was indicated by ◎, and there was elongation by ×.

Example 14
4 parts of polyvinyl butyral (softening point 87 ° C) (PVB3000-2 manufactured by Denki Kagaku Kogyo Co., Ltd.)
Ethyl alcohol 35.5 parts Water 11.5 parts Needle-like magnesium silicate 0.8 parts (Mizusawa Chemical Co., Ltd., Ade Plus SP)
After dissolving polyvinyl butyral resin in a mixture of ethyl alcohol and water, acicular magnesium silicate was added and sufficiently dispersed and mixed by a ball mill. It filtered and it was set as the coating liquid. This coating solution was uniformly coated on a biaxially stretched polyester film having a thickness of 3.5 μm by a wire bar coating method. Immediately after the coating, it is dried in hot air at 50 ° C. for 3 minutes to form a porous resin film on the polyester film. Further, a porous fiber film is prepared in the same manner as in Example 1, and this is converted into a porous resin film. Laminated. Samples were prepared by changing the adhesion amount of the porous resin film using wire bars of wire diameters of 0.6 mm, 0.8 mm, 1.0 mm, 1.2 mm, and 1.4 mm. Here, the area ratio 1 was 35% to 43%. The air permeability of the support having the porous resin membrane and the porous fiber membrane is 62 cm ³ / cm ² · sec, 53 cm ³ / cm ² · sec, 57 cm ³ / cm ² · sec, and 48 cm ³ / sec, respectively. Sufficient image density with no set-off was obtained with cm ² · sec, 39 cm ³ / cm ² · sec, stiffness of 65 mN. The relationship between stiffness and image density is shown in (1) of FIG.

  Here, the air permeability was measured by reading a 10 cm × 10 cm solid portion chart with a stencil printing machine Preport VT3820 (Ricoh Co., Ltd.), applying a perforation corresponding to the solid to the sample, and then using a permemeter [breathability]. Tester; product of Toyo Seiki Seisakusho Co., Ltd.]. Further, the film surface opening area ratio is obtained by taking an enlarged photograph of the film surface with an optical microscope (magnification 100 times) and then making an enlarged copy (200%) with a plain paper copier IMAGIO MF530 (manufactured by Ricoh Co., Ltd.) . An OHP film is superimposed on the copied object, and an opening is marked on the OHP film. The marked OHP film is read by a scanner (300 DPI, 256 gradations), and binarized using image retouching software Adobe Photoshop 2.5J. Thereafter, the image area ratio of the marked opening is measured with image analysis freeware software NIH image.

Example 15
4 parts of polyvinyl butyral (softening point 87 ° C) (PVB3000-2 manufactured by Denki Kagaku Kogyo Co., Ltd.)
Ethyl alcohol 35.5 parts Water 11.5 parts A porous resin film and a porous fiber film were formed in the same manner as in Example 14 with the above formulation. Here, the area ratio 1 was 33% to 40%. Further, 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 · sec, 26 cm ³ / cm ² · sec, 21 cm ³ / cm. It decreased to ² · sec, 17 cm ³ / cm ² · sec. The relationship between stiffness and image density is shown in (2) of FIG. As can be seen from FIG. 10, the image density of the heat-sensitive stencil master of the present invention to which a filler is added hardly changes even when the stiffness is increased. 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 film and the porous fiber film was reduced, and the ink was lowered.

Example 16
Polyvinyl acetal 2 parts Ethyl alcohol 18 parts Water 13 parts Plate-like magnesium silicate (talc) 0.4 parts (Nippon Talc Microace P4)
After adding plate-like magnesium silicate to the resin solution of polyvinyl acetal, it was dispersed and mixed by a ball mill. On the biaxially stretched polyester film having a thickness of 1.5 μm, it was uniformly coated with a wire bar in the same manner as in Example 14. Immediately after the coating, it was dried in hot air at 50 ° C. for 3 minutes to prepare a porous resin film. Thereafter, a porous fiber membrane was prepared in the same manner as in Example 1, and this was laminated on the porous resin membrane. Here, the area ratio 1 was 65% to 76%. The air permeability of the support having the porous resin membrane and the porous fiber membrane is 54 cm ³ / cm ² · sec, 60 cm ³ / cm ² · sec, 56 cm ³ / cm ² · sec, and 46 cm ³ / cm ^{2, respectively.} The relationship between the strength of the stiffness and the image density at 37 cm ³ / cm ² · sec is shown in (3) of FIG.

Example 17
Polyvinyl acetal 2 parts Ethyl alcohol 18 parts Water 13 parts A porous resin film and a porous fiber film were prepared in the same manner as in Example 6. Here, the area ratio 1 was 61% to 72%. The air permeability of the support comprising the porous resin membrane and the porous fiber membrane is 54 cm ³ / cm ² · sec, 39 cm ³ / cm ² · sec, 28 cm ³ / cm ² · sec, and 19 cm ³ / cm ^{2, respectively.} Second, at 12 cm ³ / cm ² · second, the strength decreased as the stiffness increased. The relationship between stiffness and image density is shown in (4) of FIG. It can be seen that the image density is high even when the stiffness of the plate-like magnesium silicate increases. However, in the present example in which no filler is added, the image density rapidly decreases as the stiffness increases. This phenomenon shows that the area ratio 1 is low and the porous resin film is not sufficiently formed.

Example 18
Polycarbonate 2 parts Polyvinyl butyral 1.1 parts Tetrahydrofuran 28 parts Ethyl alcohol 3.8 parts Calum titanate-based whisker 0.4 parts (Otsuka Chemical Co., Ltd. Tofika Y)
Polycarbonate is dissolved in a mixture of tetrahydrofuran and ethyl alcohol, and polyvinyl butyral is added as a material for improving adhesion between the porous resin film and the thermoplastic resin film. Disperse and mix to obtain a coating solution. On a biaxially stretched film having a thickness of 3.5 μm, a porous resin film was prepared by uniformly coating with a 1.0 mm wire bar. Thereafter, a porous fiber membrane was prepared in the same manner as in Example 1, and this was laminated on the porous resin membrane. The area ratio 1 was 44%, and the air permeability of the support including the porous resin film and the porous fiber film was 142 cm ³ / cm ² · sec. There was obtained a heat-sensitive stencil printing master with little set-off of printed matter, stiffness of 10 mN, and image density of 1.05.

Example 19
A master for thermal stencil printing of the present invention was obtained in the same manner as in Example 14 except that the atmosphere for applying the porous resin film on the film was 23 ° C., 30% RH and 23 ° C., 90% RH.

  When each master was made under the same conditions and printed on 2000 sheets, peeling of the porous resin film occurred in any of the thermosensitive stencil printing masters prepared in an atmosphere of 23 ° C. and 90% RH. .

It is a schematic cross section of an example of the master for heat-sensitive stencil printing of this invention. It is a schematic cross section of another example of the master for heat-sensitive stencil printing of the present invention. It is a schematic cross section of another example of the master for heat-sensitive stencil printing of the present invention. It is a schematic top view of a porous resin film among an example of the master for thermal stencil printing of this invention. It is a perspective view of another example of the master for heat-sensitive stencil printing of this invention. It is a schematic cross section of the master for heat-sensitive stencil printing of the present invention. It is a schematic cross section after punching by the thermal head of the master for thermal stencil printing of the present invention. 6 is a schematic diagram showing the surface of a porous resin film of a master for thermal stencil printing obtained in Example 6. FIG. 6 is a schematic diagram showing the surface of a porous resin film of a master for thermal stencil printing obtained in Example 9. FIG. It is a figure which shows the relationship between the firmness of the master for heat-sensitive stencil printing in Examples 14-17 of this invention, and image density.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Thermoplastic resin film 3 Porous resin film opening part 4 Porous resin film 4a Wall-shaped film | membrane 4b in the cell which comprises a porous resin film Cell 5 which comprises a porous resin film 5 Thermoplastic resin film thermo-piercing part 7 Porous Fiber membrane

Claims (21)

A porous resin film made of resin is formed on one surface of the thermoplastic resin film, and a porous fiber film made of a fibrous material is laminated on the surface of the thermoplastic resin film. A heat-sensitive stencil printing master characterized in that the total opening area of holes having a diameter of 5 μm or more when converted is 50% or more of the total opening area. 2. The heat-sensitive stencil master according to claim 1, wherein the cells constituting the porous resin film are bonded to each other. The heat-sensitive stencil printing master according to claim 1, wherein at least a part of the porous resin film has a softening temperature of 150 ° C. or less. 4. The heat-sensitive stencil printing master according to claim 1, wherein a part of the porous resin film is not film-like due to the influence of printing ink. A method for producing a master for heat-sensitive stencil printing, comprising: providing a porous resin film formed by foam on a thermoplastic resin film; and laminating a porous fiber film made of a fibrous material on the surface thereof. A method for producing a heat-sensitive stencil printing master, comprising: applying a flowable substance containing foam on a thermoplastic resin film; drying the film; and laminating a porous fiber film made of a fibrous material on the surface thereof. . Applying a flowable composition containing a substance that generates foam on a thermoplastic resin film, generating a gas during or after application, and laminating a porous fiber film made of a fibrous material on the surface A method for producing a heat-sensitive stencil printing master. One component of two or more components that generate gas when in contact with each other is coated on a thermoplastic resin film, and a fluid composition containing the other components is coated on the coated surface, and foamed. A method for producing a master for heat-sensitive stencil printing, comprising forming a film and laminating a porous fiber film made of a fibrous material on the surface. A fluid composition in which a gas is dissolved at a pressure higher than 1 atm is applied to a thermoplastic resin film under normal pressure, foamed, and a porous fiber film made of a fibrous material is laminated on the surface. A method for producing a heat-sensitive stencil printing master. It has a porous resin film on one surface of the thermoplastic resin film, and on the surface of the porous resin film, the total opening area of holes having a diameter of 5 μm or more when converted into a perfect circle is 4 to 80 of the total surface area. Further, a porous fiber membrane made of a fibrous material is laminated on the surface thereof, and the total opening area of pores having a diameter of 5 μm or more when converted into a perfect circle on the surface of the porous resin membrane is A heat-sensitive stencil printing master characterized in that it is 50% or more of the total opening area. The heat-sensitive stencil printing master according to claim 10, wherein at least a part of the porous resin film has a softening temperature of 150 ° C. or less. The master for heat-sensitive stencil printing according to claim 10, wherein the bending stiffness is 5 mN or more. 11. The heat-sensitive stencil printing master according to claim 10, wherein at least a part of the porous resin film remains behind the perforated part after the film is perforated by a thermal head. An organic solvent resin solution is applied onto a thermoplastic resin film, and then a poor solvent vapor or fine particles of the resin is brought into contact with the application surface to form a porous resin film, and a porous material comprising a fibrous material is formed on the surface. A method for producing a master for heat-sensitive stencil printing, comprising laminating a porous fiber film. The method for producing a heat-sensitive stencil master according to claim 14, wherein the poor solvent is water. A resin dissolved in a mixed solution of two or more solvents is applied onto a thermoplastic resin film, and the resin is precipitated by increasing the resin concentration during the drying, thereby forming a porous resin film, Furthermore, the manufacturing method of the master for thermal stencil printing characterized by laminating | stacking the porous fiber film which consists of fibrous substances on the surface. The method for producing a heat-sensitive stencil printing master according to claim 14, 15 or 16, wherein the organic solvent resin solution contains water or a hydrophilic solvent. It has a porous resin film on one surface of the thermoplastic resin film, and a porous fiber film made of a fibrous material on the surface, and the thermoplastic resin film surface is perforated so that the opening area ratio is 20% or more. The measured value in the air permeability tester is in the range of 1.0 cm ³ / cm ² · second to 157 cm ³ / cm ² · second, and the diameter when converted into a perfect circle is 5 μm on the surface of the porous resin film. A heat-sensitive stencil printing master characterized in that the total opening area of the holes is 50% or more of the total opening area. 19. The heat-sensitive stencil master according to claim 18, wherein the bending stiffness is 5 mN or more. A resin dissolved in a mixed solution of two or more solvents is applied onto a thermoplastic resin film, and the resin is precipitated by increasing the resin concentration during the drying, thereby forming a porous resin film, Furthermore, in obtaining a heat-sensitive stencil printing master by laminating a porous fiber film made of a fibrous material on the surface, the resin solution temperature to be applied is 10 ° C. to 30 ° C., and the coating atmosphere is 10 ° C. to 30 ° C. and 50 % RH or less, The manufacturing method of the master for thermal stencil printing characterized by the above-mentioned. 19. The thermal stencil printing master according to claim 1, wherein the fibrous material crosses between 2 and 7 or less per hole when punched by a thermal head. .