JP2001341454A - Master for heat sensitive stencil printing and manufacturing method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a master for heat sensitive stencil printing, whose film will not be separated from a porous film upon printing, taking-off or the like even when a long period of time has elapsed after printing and which is capable of obtaining a printing image having a high stiffness and an excellent quality reduced in curl while capable of being manufactured stably. SOLUTION: The master for heat sensitive stencil printing, having the porous resin film on a thermoplastic resin film, is manufactured by a method wherein W/O type emulsion, having the continuous phase of a solution, containing at least a resin and polyisocyanate in a solvent containing 50 wt.% of the solvent having a boiling point of 130 deg.C or less under an atmospheric pressure, is applied on the thermoplastic resin film or the same film provided with a thin layer thereon, to dry and form the porous resin film.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat-sensitive stencil master and a method of manufacturing the same.

[0002]

2. Description of the Related Art There is known a master in which porous thin paper or the like is adhered to a film as an ink-permeable support with an adhesive, and a sticking prevention layer for preventing sticking with a thermal head is provided on the film surface. Actually, a master in which a film is pasted with an adhesive to a mixture of hemp fiber, synthetic fiber, wood fiber and the like as porous thin paper and a stick prevention layer is provided on the film surface is widely used. However, such a conventional master has the following problems. (1) A large amount of adhesive accumulates in the form of a bird's web in a portion where the film is in contact with the overlapping portion of the fiber, and it is difficult for the thermal head to pierce that portion. In addition, the portion hinders the passage of ink, and printing unevenness occurs. (2) The fibers themselves impede the passage of ink, causing printing unevenness. (3) Porous thin paper or the like is expensive, and the loss due to lamination is large, and the master becomes expensive. (4) When the printed papers overlap, a set-off occurs in which the ink adheres to the back surface of the paper overlaid thereon.

Some masters have been proposed in consideration of these points. For example, JP-A-3-193445 discloses an ink-permeable support using ultrafine fibers having a fineness of 1 denier or less. According to this, the problems (2) and (4) are solved, but (1) and (3)
The problem remains. JP-A-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. Further, 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-4-7198 discloses a master for heat-sensitive stencil printing by applying a mixed solution of 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 stencil printing machine (Print Gokko plate making machine) manufactured by Riso Kagaku Kogyo Co., Ltd., and printing is performed using an ink jet recording ink (HG-4800 ink) manufactured by EPSON. However, the porous layer obtained by this method has poor printing ink properties, and a conventional heat-sensitive stencil printing ink cannot provide a sufficient density during printing and is not practical.

Japanese Patent Application Laid-Open No. 54-33117 discloses a master which does not use a support and consists essentially of a film.
The problem of (3) is solved, but on the other hand, it raises a new problem. One of the problems is that when the film has a thickness of 10 μm or less, its stiffness is weak, and it is difficult to convey the film. As a solution to this problem, Japanese Patent Publication No. 5-70595 discloses that a film is wound around a peripheral wall of a stencil printing machine without being cut, and the entire film rotates with the rotation of the plate cylinder during printing. The idea to do is shown. However, in this method, since the film and the plate receiving / discharging unit rotate with the rotation of the plate cylinder during printing, the moment of rotation increases,
Further, there is a problem that the deviation from the rotation axis of the center of gravity is large, and to solve these problems, the printing press is heavy and must be enlarged. Another is that when the film has a thickness of 5 μm or more, its thermal sensitivity is low, and it is difficult to perform perforation by a thermal head.

As means for solving these problems, Japanese Patent Application Laid-Open No. Hei 10-24667 by the present inventors discloses a resin,
A master in which a mixed solution containing the good solvent and the poor solvent is applied to a film and dried to form a porous film has been proposed. In the drying process, in the drying process, the relative poor solvent is increased by evaporation of the good solvent, the resin is precipitated by concentration of the liquid, and the resin is dried, and a porous film composed of a three-dimensional network is formed on the film. You. And this master is superior to previously known masters, and there are few problems. However, the solvent of the coating solution, the ratio of the poor solvent, the coating conditions, and the like must be accurately maintained, and it is difficult to apply for a long time, and it is practically difficult to continuously form a porous film having desired characteristics. there were.

The present inventors have also invented a master in which a fluid mainly composed of a W / O (water-in-oil) emulsion is coated on a film and dried to form a porous film. I have. This master also has excellent characteristics, but has the following problems. That is, when a large amount of printing is performed and the master is artificially jammed on the plate cylinder at a low temperature and peeled off from the plate cylinder to remove it, the film of the master and the porous film are peeled off and the porous film becomes a plate. Sometimes left on his torso. This phenomenon was particularly noticeable when the printed master remained on the plate cylinder for a long time. In addition, when printing is performed using a printing paper having a particularly large thickness, for example, a postcard or an envelope, a portion of the porous film corresponding to the edge of the postcard or the envelope may be separated from the film by receiving a particularly large impact. Further, it has been found that in a high-humidity environment, stiffness may decrease and curl may occur in a high-humidity or low-humidity environment, which may hinder conveyance.

[0008]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned circumstances of the prior art, and is intended to be used with a master film even after a long time has elapsed after printing, or during printing or plate discharge. A master for heat-sensitive stencil printing (hereinafter also referred to as a master) capable of obtaining a printed image of excellent image quality without peeling of the porous film, having a large stiffness and having little curl, and capable of being manufactured stably. ) Is the task.

[0009]

According to the present invention, the W
As a result of further studying a master having a porous film formed by applying a fluid mainly composed of an / O (water-in-oil) emulsion on a film and drying the film, various problems were observed during the transfer of the master and the printing. Found no master and completed the present invention. A first aspect of the present invention is a heat-sensitive stencil master having a porous resin film on a thermoplastic resin film, wherein the porous resin film has a W / O (water-in-oil droplet) in which a solution containing a resin and a polyisocyanate is used as a continuous phase. A) a stencil printing master formed by applying and drying a type emulsion on the thermoplastic resin film. A second aspect of the present invention is the first thermosensitive stencil printing master, wherein a thin layer is provided between the thermoplastic resin film and the porous resin film. A third aspect of the present invention is that when a thermoplastic resin film is perforated to an opening area ratio of 20% or more, the porous resin film has an air permeability of 2.0 to 160 cm ³ / c.
m ² · sec, the first or second thermosensitive stencil master.

A fourth aspect of the present invention is to form a thin film on a thermoplastic resin film or a thermoplastic resin film provided with a thin layer.
A W / O (water-in-oil) emulsion having a continuous phase of a solution containing at least a resin and polyisocyanate in a solvent containing 50% by weight or more of a solvent having a boiling point of 130 ° C. or less at atmospheric pressure is applied. A method for manufacturing a master for heat-sensitive stencil printing, characterized by drying to form a porous resin film. A fifth aspect of the present invention is the fourth method for producing a heat-sensitive stencil master, wherein the viscosity of the aqueous system of the W / O (water-in-oil) emulsion is greater than the viscosity of water. The master of the present invention has a structure which is suitable for a very low-viscosity ink used for ink jet recording or a structure which is completely different from a known heat-sensitive stencil master, as disclosed in JP-A-3-240596. It has a function.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be shown, and the present invention will be described in more detail. The master of the present invention is characterized in that a thin layer is provided on one side of the film or on the film surface as necessary, and a porous film mainly composed of a resin containing a polyisocyanate reaction product is provided thereon. Is what you do. The function of the thin layer is, first, to strengthen the adhesion between the film and the porous resin film, to improve the peeling of the film and the porous film at the time of printing, and, second, to strengthen the stiffness, third, To reduce the curl.

The materials constituting the heat-sensitive stencil sheet will be described. The thermoplastic film used in the present invention is preferably used for a heat-sensitive stencil sheet such as a vinyl chloride / vinylidene chloride copolymer film, a polypropylene film, and a polyester film. Can be used but has a melting energy of 3
To 11 cal / g polyester film (JP-A-62
JP-A-149496), a polyester film having a crystallinity of 30% or less (see JP-A-62-282983), 50 mol% of butylene terephthalate unit.
Polyester film containing the above (JP-A-2-15839)
For example, polyesters that can be perforated with low energy, such as those disclosed in Japanese Patent Application Laid-open No. 1 (Kokai) No. 1). Of course, the thermoplastic film used in the present invention is not limited to a stretched film. The thickness of the film is preferably in the range of 1.5 to 10.0 μm. If the thickness of the film is too thin, it is difficult to apply the coating material for forming a porous film, and if it exceeds 10 μm, it becomes difficult to perforate with a thermal head.

W / O used for forming porous membrane in the present invention
As the resin dissolved in the continuous layer composed of the solvent of the emulsion, basically any thermoplastic resin can be used depending on a combination of a solvent, an emulsifier and a viscous aqueous solution, but a resin having a hydrophilic group is preferable. With other resins, the emulsion became unstable, water separation occurred, and water streaks occurred during coating. As the hydrophilic group, -SO _{3
H, -SO 3 M, -OSO 3} H, OSO 3 M, -COO
_{M, -NR 3 X, -COOH,} -NH 2 -CN, -OH,
_{-NHCONH 2 - (OCH 2 H 2} -, - CH 2 OCH 3 O
CH ₃ —COOCH ₃ —CS, a phosphate group, and various groups generated by condensation of these groups.
(R: alkyl group, M: alkali metal or —NH
₄ X: halogen) Further, as the resin, acrylic, ester, urethane, olefin, vinylidene chloride, epoxy, amide, styrene, etc.
Vinyl-based, cellulose derivatives, modified products thereof, and copolymers are preferred, and vinyl-butyral-based, urethane-based, and polyvinyl acetate-based polymers are particularly preferably used. These polymers are also used as a mixture.

The porous film here is not necessarily a film having pores continuous in the thickness direction from the surface to a film or a thin layer. A thin film having no pores may be formed of the resin contained in the above. It is unclear what mechanism the thin film is formed by, but as the solvent and water of the resin evaporate from the surface during drying, the resin that forms a continuous layer that uniformly wets the film (or thin layer) surface It is assumed that the solvent gradually decreases from the solution to form a resin thin film as it is. The thin film has little effect on thermal sensitivity.

In order to control the formation, strength, pore size, and stiffness of the porous film, additives such as fillers can be added to the porous film as needed. Here, the filler is a concept including pigments, powders, and fibrous substances. Among them, needle-like, plate-like, or fibrous fillers are particularly preferable. Specific examples thereof include magnesium silicate, sepiolite, potassium titanate, wollastonite, zonolite, gypsum fiber, mineral needle fillers such as,
Artificial mineral needle filler such as non-oxide needle whisker, oxide whisker, double oxide whisker, plate filler such as mica, glass flake, talc, carbon fiber, polyester fiber, glass fiber, vinylon fiber ,
Natural or synthetic fibrous fillers such as nylon fiber and acrylic fiber can be used. Examples of the pigment include organic polymer particles such as vinyl acetate, polyvinyl chloride, and polymethyl acrylate, and inorganic pigments such as carbon black, zinc oxide, titanium dioxide, calcium carbonate, and silica. The addition amount of these additives is preferably 5 to 2 with respect to the resin.
00% by weight. If the amount is less than 5% by weight, curling tends to occur, and if the amount is more than 200% by weight, the strength of the porous film may be reduced. Further, an antistatic agent, a stick inhibitor, a surfactant, a preservative, an antifoaming agent and the like can be used in combination with the porous membrane of the present invention as long as the effects of the present invention are not impaired.

One of the features of the present invention is that the reactive polyisocyanate is contained in a continuous layer containing a solvent which is basically immiscible with water. The polyisocyanate reacts with a resin having a hydrophilic group to increase the strength of the porous film itself and the adhesive strength between the porous film and the film or thin layer, and the film and the porous film may be peeled off even after a long time after printing. It is possible to provide a master having no stiffness, a master having a large stiffness, and a master having little curl. Examples of the polyisocyanate include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, diphenylmethane-4,4′-diisocyanate, polymethylene polyphenyl polyisocyanate, hexamethylene diisocyanate, and modified products and mixtures thereof. Used. An appropriate amount of the polyisocyanate is 1 to 50% by weight of the resin having a hydrophilic group. If it is less than 1%, the effect is small, and if it is more than 50%, the reaction proceeds too quickly to make application difficult, and a porous film is hardly formed. Since polyisocyanate reacts rapidly in the presence of water and loses its activity, care must be taken when preparing an emulsion coating solution. First, a resin having a hydrophilic group is dissolved in a solvent, additives such as a surfactant and a pigment are added, and the mixture is well stirred and dispersed. Next, a predetermined amount of polyisocyanate is added and stirred, and immediately, a predetermined amount of water is added and stirred and dispersed to form an emulsion. This liquid must be applied in as short a time as possible. 60 depending on the amount and type of polyisocyanate
It is desirable to use up within minutes. "Solvent which is basically immiscible with water" means that the solvent contains no more than 20% (20%) of water.
(° C., weight%).

In the present invention, a solvent having a boiling point of 130 ° C. or less
Unless a solvent containing 0% by weight or more is used, a desired porous film is hardly formed. Although the reason is not clear, it is presumed that if water evaporates while the continuous layer has fluidity in the drying process, no pores are formed. Examples of preferably used solvents include methylene chloride, chloroform, ethyl acetate, methyl acetate, diethyl ether, carbon tetrachloride, cyclohexane, hexane, pentane, benzene, ME
K, toluene and the like. It has been found that when the water system of the W / O (water-in-oil) emulsion of the present invention is thickened from pure water, the emulsion becomes stable and hardly breaks. A suitable viscosity is 10 to 500 centipoise at the liquid temperature at the time of application. When it is less than 10 centipoise, the effect of stabilizing the emulsion is small, and when it exceeds 500 centipoise, drying becomes slow and production efficiency is deteriorated. As a thickening means, addition of a water-soluble compound having a thickening effect is applied. Examples include, but are not limited to, polyvinyl alcohol, carboxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, polyacrylic acid, polyethylene glycol, polyvinyl pyrrolidone, and the like.

The multiplicity formed by the emulsion of the present invention
The porous membrane is made of a fluid mainly composed of a W / O emulsion.
Directly on the film or on a thin layer formed on the film
It is formed by coating and drying.
After the ink has dried, it becomes a hole through which ink passes, and the resin in the solvent
(Additives such as fillers and emulsifiers may be included)
Is a structure. Formation of porous membrane, strength, pore size,
In order to adjust the stiffness, etc., if necessary in the porous membrane
Additives such as fillers can be added. Among them
In particular, needle-like, plate-like, or fibrous fillers are preferred.
No. Relatively lipophilic for formation of W / O emulsion
HLB (Hydrophyric-Lyophir)
ic Balance) is effective.
There is a surfactant with an HLB of 8 to 20 in the water layer
Then, a more stable and uniform W / O emulsion can be obtained.
You. The use of polymeric surfactants has also led to more stable and uniform
This is one of the ways to get a lugeon. Emulsion method
Of the porous membrane itself after drying is 1 to 20 g / m^TwoYes,
Preferably 3 to 10 g / m^Twois there. 1g / m^TwoSmaller
The set-off of the printed matter is not bad because the ink adhesion amount is not controlled.
Therefore, the stiffness of the master itself is reduced. 20g / m ^Two
Exceeding this will impede the passage of ink, resulting in poor image quality.
It leads to high cost and waste of resources.

Examples of the thin resin material provided on the film include polyester resin, polyether resin,
Polyurethane resin, polyvinyl resin such as polyvinyl acetate, polyvinyl butyral, vinyl chloride-vinyl acetate copolymer, vinyl chloride-vinylidene chloride copolymer, vinyl chloride-acrylonitrile copolymer, styrene-acrylonitrile copolymer, polyamide such as polybutylene, nylon, and polyphenylene Oxide, (meta)
Acrylic esters, polycarbonates, copolymers, mixtures, and modified products thereof are used. Among these resins, polyester polyols and polyether polyols are particularly preferable. More preferably, the softening point is 60-
It is a mixture of polyester polyol, polyether polyol and polyisocyanate at 150 ° C. Here, OH / NCO ranges from 1 / 0.1 to 1/20,
What is necessary is just to select freely according to required characteristics.

Further, various fillers, antistatic agents, anti-stick agents, surfactants, preservatives, defoamers, modifiers and the like may be used in the thin layer within a range not to impair the effects of the present invention. Can be. The thickness of the thin layer after drying is preferably 0.01
-0.8 μm, more preferably 0.03-0.2 μm
It is. If the thickness of the thin layer after drying is less than 0.01 μm, the effect of improving the adhesiveness, stiffness and curling is small, and if it exceeds 0.8 μm, the heat perforation sensitivity is adversely affected. The material of the thin layer, the thickness after drying, is determined by several experiments. That is, an appropriate dry adhesion amount (thickness) of a thin layer is determined in consideration of the desired adhesiveness, image quality and the like. If it is difficult to measure the thickness directly, the thickness can be calculated from the weight and specific gravity. When a thin film is present at the interface between the film and the porous film, there is a concern that the thermal head has an adverse effect on perforation heat sensitivity, but it has been found that it has practically no effect. This is presumed to be mainly because the thickness of the thin layer is smaller than the thickness of the film. The thin layer is easily formed by a coating method such as a general roll coater and a wire bar coater. When using biaxially stretched polyester as the film and butyral resin as the porous membrane material,
As the thin layer, a polyester, a reaction product of a polyol and an isocyanate, an isocyanate polymer, or the like is suitably used.

Also in the master of the present invention, a stick prevention layer for preventing stick with a thermal head can be provided on the opposite surface of the film on which the porous film is formed.
In this case, as the stick prevention agent to be used, a silicone-based release agent, a fluorine-based release agent, a phosphate ester-based surfactant, and the like generally used in a conventional heat-sensitive stencil master can be used. An antistatic agent for preventing generation of static electricity may be added.

The porous tree of the master for heat-sensitive stencil printing of the present invention
The oil film has an air permeability of 2.0 to 160 cm. ^Threecm^TwoSeconds are good
Good. The air permeability is 2.0cm^Threecm^TwoLess than a second
Printed matter with low image density, where ink hardly passes through the master
I can only get it. 160cm^Threecm^TwoIf greater than seconds in
Image is too blurred or set off (overprinted printed
Phenomenon that the ink of the previous print adheres to the back of the paper)
appear. The "air permeability" is the air passage of the perforated master
Quantity, and when the master is used for printing,
Demonstrated master ink passability suitable for obtaining printing characteristics
Things. To control the air permeability,
Solution / water ratio of the active agent added to the emulsion
Type, amount, type, amount and dispersion of thickener added to water
Condition, amount of adhesion, application conditions, and the like. For example, Emarjo
If the solvent / water ratio of the solvent is increased, the air permeability tends to decrease.
And tend to grow under mild dispersion conditions.

This air permeability is measured as follows.
First, the master film is perforated so that the opening area ratio of its surface becomes 20 to 80% under specific conditions. At this time, the thin layer is also perforated at the same time. For this sample, P
The air permeability is measured using an ermemeter (air permeability tester, manufactured by Toyo Seiki Seisaku-sho, Ltd.). Open area ratio is 20 ~
80% arbitrary sample permeability is 2.0-160cm
If the length is ³ cm ² seconds, the master is used as a thermosensitive stencil printing master according to the present invention. Specifically, samples with the opening area ratio of 20%, 50%, and 80% for the same product are prepared. In order to obtain a desired opening area ratio in the film, it is possible to arbitrarily change the energy applied to the thermal head and / or the size of the heating element of the thermal head.
A PRIPORT VT 3820 (manufactured by Ricoh: equipped with a thermal head manufactured by Toshiba Corporation) was used as the perforation apparatus.
Perform plate making with a solid chart of cm × 10 cm.

The opening area ratio is a ratio of the total area of the through holes on the film surface of the master to the entire area. This measurement is performed as follows. That is, a magnified photograph of the perforated master is taken with an optical microscope (magnification: 100 times), and then enlarged and copied by a plain paper copier (Imagio 530, manufactured by Ricoh Company). The opening is marked on the OHP film. Scan the OHP film with a scanner (300 DPI
Image retouching software / Ado
Binarization is performed using be (registered trademark) Photoshop 2.5J. Then, the area ratio of the opening marked by the image analysis software is measured. In the above example, for the sake of convenience, the film was measured with the opening area ratio being 20, 50, and 80%. However, the air permeability of any sample having an opening area ratio of 20% or more and 80% or less was 2.0 to 160 cm. ³ cm ²
If it is a second, the master for heat-sensitive stencil printing according to the present invention is used. For example, the opening area ratio is 65% and the air permeability is 2.0 to 16
In the range of 0 cm ³ cm ² seconds, the master is almost 6
When the film is pierced and provided for printing with an opening area ratio of 5%,
The printing characteristics aimed at by the present invention can be obtained. The reason why the air permeability is measured when the opening area ratio is 20% or more is that if the air permeability of the porous film is less than 20%, the passage of the ink is prevented by the film when used for printing. That's why.

[0025] Test method for printing adhesion strength between porous film and film using PRIPORT VT 3820 manufactured by Tohoku Ricoh Co., Ltd.
3000 sheets of a solid black image of A5 size are printed. After a lapse of 7 days and 30 days, one end of the master on the plate cylinder that has been intentionally broken on the plate cylinder in an atmosphere of 5 ° C. is held with both hands, and is vigorously peeled off from the plate cylinder. When the film and the porous film did not peel at all, ○: when the film and the porous film were peeled by half or more of the area, ×: when the middle
And

Curl Test Method A sample of 10 cm × 10 cm is left on a flat table in an atmosphere of 20 ° C. 90% RH and 20 ° C. 10% RH for 10 minutes. The curls on the four sides were measured, and when the average value was 10 mm or less in any atmosphere, it was evaluated as "x" when the humidity was low or high, or when both atmospheres were rolled into a cylindrical shape, and when the average was not, the evaluation was "." Printing is PRIPORT VT 382
0 system. Punching sensitivity: A mark indicates that the film portion of the master was completely punctured by the thermal head, a mark indicates that the pierced hole had a partially reduced diameter, and a mark indicates that the film portion was not partially punctured.

Print unevenness: A printed image is observed with the naked eye, and a bleeding, blurring, and density unevenness are better than the current master (VT-2 master, manufactured by Ricoh Company). , X that is inferior to the current master,
Indicated by Set-off: Observation of the printed matter with the naked eye, 〇 indicates that the master is superior to the current master (manufactured by Ricoh, VT-2 master), △ indicates the equivalent to the current master, and × indicates that the master is inferior to the current master.
Indicated by Stability of Coating Solution Using a die coater, coating was continuously performed on a biaxially stretched polyester film having a thickness of 2 μm at a liquid temperature of 20 ° C. at a coating speed of 10 m / min. Uneven coating or streak did not occur for 30 minutes or more.
What occurred in 10 to 30 minutes was marked as Δ.

[0028]

Embodiments of the present invention will be described below.

Example 1 Polyvinyl butyral (manufactured by Sekisui Chemical Co., Ltd., BHS) 2.5 parts by weight Ethyl acetate 30.0 Sorbitan monooleate (manufactured by Toho Chemical Co., Ltd., Sorbon S80) 0.15 Talc 0.63 or more was dissolved. Dispersed. To this, 0.25 parts by weight of 2,4-tolylene diisocyanate was dissolved, and 15.0 parts by weight of a 1% aqueous solution of hydroxyethyl cellulose was added with stirring to obtain an emulsion coating solution. 20 ° C 50
After drying with a gravure roll on a biaxially stretched polyester film having a thickness of 2.0 μm in a% RH atmosphere, the resultant was applied so that the adhesion amount was 7.0 g / m ² to form a porous film.
The coating speed was 10 m / min and the drying temperature was 60 ° C. A mixture of silicone oil and a nonionic antistatic agent was applied to the surface of the film opposite to the surface on which the porous film was formed so that the adhesion amount after drying was 0.05 g / m ² to obtain a master.

Example 2 Polymethacrylic acid was added to the water of Example 1 to adjust the viscosity at 20 ° C. to 300 centipoise. Others were applied similarly to Example 1. 7.2 g / m after drying
There were ^two . On the side opposite to the one where the porous membrane of the film was formed,
A mixture of silicon and a cationic antistatic agent was applied so that the adhesion amount after drying was 0.05 g / m ² to obtain a master.

Example 3 A solution of 2% ethyl acetate / toluene (OH / NCO = 1/1) of polyester (Vylon 50AS, manufactured by Toyobo Co., Ltd.) and isocyanate (Coronate L, manufactured by Nippon Polyurethane Co., Ltd.) was added to the film of Example 1. Was applied, and after drying, a thin layer having an adhesion amount of 0.02 g / m ² was obtained (when the specific gravity was 1.4, the film thickness was 0.014 μm). On top of this, the coating solution of Example 2 was applied in an atmosphere of 20 ° C. and 50% RH so as to have an adhesion amount of 7.5 g / m ² after drying to form a porous film.
The drying temperature was 60 ° C. A mixture of silicon and a nonionic antistatic agent was applied to the surface of the film opposite to the surface on which the porous film was formed so that the adhesion amount after drying was 0.05 g / m ² to obtain a master.

Comparative Example 1 In the emulsion of Example 1, 2,4-tolylene diisocyanate was not added. The other conditions were the same as in Example 1. Comparative Example 2 The same procedure as in Example 1 was carried out except that xylene having a boiling point of 140 ° C. was used instead of ethyl acetate in the emulsion liquid of Example 1. No good porous film was formed.

[0033]

[Table 1]

In Examples 1 and 2, there was no peeling after leaving for 7 days, but a little peeling after leaving for 30 days. In Example 3, there was no peeling. In Comparative Example 2, when xylene having a boiling point of 140 ° C. was used, a good porous film was not formed. Further, in Example 3, the rigidity was also improved.

[0035]

According to the present invention, since the above-mentioned structure is employed, the porous film does not peel off after printing while maintaining excellent image quality and a small set-off characteristic, and is excellent in liquid stability and curl. A small, strong master is provided.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2H114 AB23 AB25 AB28 BA06 DA24 DA41 DA49 DA56 DA60 DA79 EA08 EA10 FA09 FA14 GA34 GA38 4F006 AA35 AB37 BA01 BA05 BA12 CA01 DA04

Claims (5)

[Claims] 1. A master for stencil printing having a porous resin film on a thermoplastic resin film, wherein the porous resin film is a W / O (water-in-oil) type in which a solution containing a resin and polyisocyanate is a continuous phase. A master for heat-sensitive stencil printing, wherein the master is formed by applying an emulsion onto the thermoplastic resin film and drying. 2. The master for heat-sensitive stencil printing according to claim 1, wherein a thin layer is provided between the thermoplastic resin film and the porous resin film. 3. The thermoplastic resin film having an opening area ratio of 20
% Or more, the porous resin film has an air permeability of 2.% or more.
The master for heat-sensitive stencil printing according to claim 1, wherein the master stencil printing speed is 0 to 160 cm ³ / cm ² · second. 4. On a thermoplastic resin film or a thermoplastic resin film provided with a thin layer, a resin and a polyisocyanate are mixed with a solvent containing 50% by weight or more of a solvent having a boiling point of 130 ° C. or less under atmospheric pressure. A W / O (water-in-oil) emulsion containing a solution containing at least a continuous phase is applied and dried to form a porous resin film, and a thermosensitive resin having a porous resin film on a thermoplastic resin film A method of manufacturing a stencil master. 5. The method for producing a master for heat-sensitive stencil printing according to claim 4, wherein the viscosity of the water system of the W / O (water-in-oil) emulsion is higher than the viscosity of water.