JP4728699B2 - Master for heat-sensitive stencil printing and method for producing the same - Google Patents

Description

  The present invention relates to a heat-sensitive stencil printing master having excellent transportability and high antistatic performance, and a method for producing the heat-sensitive stencil printing master.

  Conventionally, a heat-sensitive stencil printing master in which a porous thin paper obtained by combining natural fibers and synthetic fibers alone or in combination as a porous support is bonded to a thermoplastic resin film with an adhesive has been used. In this heat-sensitive stencil printing master, various proposals have been made with the aim of further improving transportability, ink permeability, antistatic performance, and the like. For example, Patent Document 1 proposes to use a thin paper made of synthetic fibers having a fineness of 1 denier or less as the porous support. However, this proposal is not sufficient to solve the above problem. Patent Document 2 proposes a method of forming a radiation curable resin pattern having a substantially closed shape on a thermoplastic resin film by a printing method such as gravure, offset, or flexo. However, in the printing method, it is difficult to reduce the line width of the resin pattern to 50 μm or less, and there is a problem that printing unevenness occurs because the printing portion cannot be punched.

  Patent Document 3 proposes a thermal stencil printing master in which a dispersion containing a water-dispersible polymer and colloidal silica is applied to the surface of a thermoplastic resin film and dried. It is used in combination with a low-viscosity inkjet ink. However, this proposal has a problem that the pore diameter of the porous layer is small, and the ink for conventional stencil printing does not pass through the ink, and a sufficient printing density cannot be obtained.

Patent Document 4 proposes a heat-sensitive stencil printing master that is substantially composed of only a thermoplastic resin film that does not use a porous support. According to this proposal, a film having a high thermal shrinkage rate and a thickness of 3 μm or less has good punchability by a thermal head, and the print quality is excellent.
However, this heat-sensitive stencil master has a weak stiffness and is difficult to transport with a printing press. To improve transportability, the use of a thick thermoplastic resin film reduces the punchability of the thermal head. Therefore, there is a problem that uneven printing occurs.

  Further, there has been proposed a thermosensitive stencil printing master having a porous resin film obtained by applying a fluid to one side of a thermoplastic resin film and drying it (see Patent Document 5 and Patent Document 6). However, since the proposed porous resin film has a lower porosity and lower heat insulation than conventional thin paper, the perforation diameter by the thermal head is high, but the perforation diameter tends to be small. This means that the thermal sensitivity is lowered, and it cannot be said to be a favorable tendency. Further, it is difficult for the heat-sensitive stencil printing master to strengthen the stiffness only with the porous resin film.

Patent Document 7 and Patent Document 8 propose a master for thermal stencil printing in which a porous resin film and a porous fiber film are sequentially laminated on one surface of a thermoplastic resin film.
However, these heat-sensitive stencil printing masters use a resin having low hydrophilicity for the purpose of suppressing humidity dependence, and the resin is easily charged. Sticking to the inner wall of the printer, smooth conveyance and winding around the printing drum are hindered, and the thermal stencil printing master is wound with wrinkles on the drum, or jamming occurs during winding and the printing machine There is a problem of stopping.

  In addition, a low molecular surfactant type antistatic agent is usually used in a conventional heat-sensitive stencil printing master. Such low molecular weight surfactants have the disadvantage that the antistatic performance is deteriorated due to the movement of the surfactant itself, or the antistatic performance depends on environmental changes such as humidity.

  Therefore, the present situation is that no excellent thermal stencil printing master having a sufficient stiffness without causing jamming or wrinkles on the drum due to static electricity in the printing press has yet been provided.

Japanese Patent Laid-Open No. 3-193445 Japanese Patent Laid-Open No. 62-198459 JP-A-3-240596 JP 54-33117 A JP-A-8-332785 Japanese Patent Laid-Open No. 10-24667 JP-A-10-147075 Japanese Patent Laid-Open No. 10-236011

  This invention is made | formed in view of this present condition, and makes it a subject to solve the said various problems in the past and to achieve the following objectives. That is, the present invention is a water-based coating material that does not cause poor conveyance due to static electricity in the printing press and poor winding around the printing drum, has sufficient stiffness, has little deterioration in antistatic performance, and is water-based. It is an object of the present invention to provide a thermal stencil printing master excellent in environmental properties and a method for producing the thermal stencil printing master.

As a result of intensive studies by the present inventors in order to solve the above-described problems, a conductive material having a dry adhesion amount of 0.01 to 2.0 g / m ² including an ionic polymer having a Tg of 10 ° C. or higher. By using the material as an antistatic agent, it has sufficient stiffness without causing poor transport due to static electricity in the printing press and poor winding around the print drum, and it is a water-based material. It was found that it is possible to reduce this.

The present invention is based on the above findings of the present inventors, and means for solving the above problems are as follows. That is,
<1> A thermoplastic resin film, and a porous support including at least one of a porous resin film and a porous fiber film on at least one surface of the thermoplastic resin film. The support comprises at least a conductive material having a dry adhesion amount of 0.01 to 2.0 g / m ² and containing an ionic polymer having a Tg of 10 ° C. or higher. Master. In the master for heat-sensitive stencil printing according to <1>, by providing a porous support containing a conductive material containing at least an ionic polymer of a thermoplastic resin film, there is no problem due to static electricity that occurs during transportation. It is also possible to maintain transportability. In addition, by setting the amount of the conductive material adhered in the range of 0.01 to 2.0 g / m ² , it has a sufficient antistatic function to eliminate static electricity that occurs during transportation, and is also necessary during transportation. It is also possible to give a strong stiffness. Furthermore, since the ionic polymer glass transition temperature (Tg) is 10 ° C. or higher, blocking is prevented and normal plate making and conveyance are possible.

<2> The outermost surface layer of the porous support is a porous resin film, and the porous resin film contains an ionic polymer having a Tg of 10 ° C. or higher, and the dry adhesion amount is 0.01 to 2.0 g. The master for heat-sensitive stencil printing according to <1>, which contains a conductive material of / m ² .
<3> The porous support has a porous resin membrane on the porous fiber membrane, and the porous resin membrane contains an ionic polymer having a Tg of 10 ° C. or higher, and the dry adhesion amount is 0.00. The heat-sensitive stencil printing master according to any one of <1> to <2>, which contains a conductive material of 01 to 2.0 g / m ² .
<4> The outermost surface layer of the porous support is a porous fiber membrane, and the porous fiber membrane contains an ionic polymer having a Tg of 10 ° C. or higher, and the dry adhesion amount is 0.01 to 2.0 g. The master for heat-sensitive stencil printing according to <1>, which contains a conductive material that is / m ² .
<5> The porous support has a porous fiber membrane on the porous resin membrane, and the porous fiber membrane contains an ionic polymer having a Tg of 10 ° C. or higher, and the dry adhesion amount is 0.00. The heat-sensitive stencil printing master according to any one of <1> and <4>, which contains a conductive material having an amount of 01 to 2.0 g / m ² .
<6> The heat-sensitive stencil printing master according to any one of <1> to <5>, wherein the ionic polymer is an anionic polymer.
<7> The heat-sensitive stencil printing master according to <6>, wherein the anionic polymer contains an alkali metal salt.

<8> The heat-sensitive stencil printing master according to any one of <1> to <7>, wherein the conductive material includes a surfactant. In the heat-sensitive stencil master described in <8>, since the conductive material contains a low molecular surfactant, the wettability between the conductive material and the porous support is improved, and the film continuity is maintained. Thus, the antistatic function can be improved.
<9> The thermosensitive stencil printing master according to <8>, wherein the low molecular surfactant is a nonionic surfactant.
<10> The heat-sensitive stencil printing master according to any one of <8> to <9>, wherein the HLB value is 9 or more.
<11> The heat-sensitive stencil printing master according to any one of <8> to <10>, wherein the static contact angle with respect to the polyethylene terephthalate film is 5 to 70 °. In the thermosensitive stencil printing master described in <11>, since the static contact angle is 5 to 70 °, the wettability to the substrate to be applied is improved, the film continuity is maintained, and the antistatic function Can be improved.

<12> The heat-sensitive stencil according to any one of <1> to <11>, wherein the surface resistance value on the porous support side of the heat-sensitive stencil printing master is 1.0 × 10 ^{5 to} 1.0 × 10 ¹³ Ω. Master for printing. In the heat-sensitive stencil printing master described in <12>, the surface resistance value on the porous support side is 1.0 × 10 ^{5 to} 1.0 × 10 ¹³ Ω, so that static electricity generated during plate making and transporting Therefore, it is possible to maintain the transportability without any trouble due to static electricity.
<13> The master for thermal stencil printing according to any one of <1> to <12>, wherein the conductive material is attached to the porous support.

<14> The heat-sensitive stencil printing master according to any one of <1> to <13>, wherein the porous fiber membrane contains a synthetic fiber. In the heat-sensitive stencil printing master described in <14>, since the porous support is composed of synthetic fibers, the stiffness does not depend on the environment such as humidity and can have sufficient strength. It is.
<15> The heat-sensitive stencil printing master according to any one of <1> to <14>, wherein the porous fiber membrane contains a composite fiber of a synthetic fiber and a natural fiber. In the heat-sensitive stencil printing master described in <15>, the porous support has a composite structure of synthetic fibers and natural fibers, so that the cost can be reduced while maintaining strength such as stiffness.

  <16> The thermal stencil printing master according to any one of <1> to <15>, wherein the bending stiffness in the thermal stencil printing master is 20 to 110 mN in the MD direction. In the heat-sensitive stencil printing master described in <16>, since the bending stiffness is 20 to 110 mN in the MD direction, there is no problem that occurs during transportation, and it is also possible to prevent problems such as plate-wrinkling. It is.

<17> A porous support forming step of forming a porous support including at least one of a porous resin film and a porous fiber film on at least one surface of the thermoplastic resin film; And a conductive material coating step of coating a surface with a conductive material coating solution containing at least an ionic polymer. A method for producing a heat-sensitive stencil printing master. In the method for producing a heat-sensitive stencil master described in <17>, a high-quality heat-sensitive stencil master can be produced efficiently by a porous support forming step and a conductive material applying step. it can.
<18> The method for producing a heat-sensitive stencil printing master according to <17>, wherein the conductive material coating solution is aqueous and has no flash point. In the method for producing a thermosensitive stencil master described in <18>, since the conductive material coating liquid is water-based, it is possible to reduce the burden on the environment.
<19> The method for producing a heat-sensitive stencil printing master according to any one of <17> to <18>, wherein the coating liquid for conductive material has a viscosity at 25 ° C. of 2 to 80 mPa · s. In the method for producing a heat-sensitive stencil printing master described in <19>, the porous support is entrained at the time of coating by setting the viscosity at 25 ° C. of the coating liquid for conductive material to 2 to 80 mPa · s. It is possible to eliminate problems such as.
<20> The method for producing a heat-sensitive stencil printing master according to any one of <17> to <19>, wherein the pH of the coating liquid for a conductive material is 4 to 9. In the method for producing a heat-sensitive stencil printing master described in <20>, by setting the pH in the conductive material coating solution to 2 to 9, the problem of corrosion of the coating equipment can be solved, and further charging It is possible to minimize the deterioration of performance.

  According to the present invention, the conventional problems can be solved, and there is no occurrence of poor conveyance due to static electricity in the printing press and poor winding around the printing drum, and there is sufficient stiffness and little deterioration in antistatic performance. Since it is an aqueous coating material, it can provide a thermal stencil printing master that is excellent in environmental properties and a method for producing the thermal stencil printing master.

(Master for thermal stencil printing)
The master for heat-sensitive stencil printing of the present invention has a thermoplastic resin film and a porous support containing at least one of a porous resin film and a porous fiber film on at least one surface of the thermoplastic resin film. In addition, other layers are provided as necessary.

Here, in the heat-sensitive stencil printing master, for example, as shown in FIGS. 1 and 4, the outermost surface layer of the porous support 1 is a porous resin film 2, and the porous resin film 2 has a Tg of An embodiment containing a conductive material containing an ionic polymer having a temperature of 10 ° C. or higher is preferable, and the porous support 1 has a porous resin film 2 on a porous fiber film 3 as shown in FIG. An embodiment in which the porous resin film 2 contains a conductive material containing an ionic polymer and having a dry adhesion amount of 0.01 to 2.0 g / m ² is particularly preferable.
In the heat-sensitive stencil printing master, for example, as shown in FIGS. 2 and 3, the outermost surface layer of the porous support 1 is a porous fiber film 3, and the porous fiber film 3 has a Tg of 10 An embodiment containing a conductive material containing an ionic polymer having a temperature of not lower than ° C. and having a dry adhesion amount of 0.01 to 2.0 g / m ² is preferable, and the porous support 1 is porous as shown in FIG. A mode in which the porous fiber film 3 is provided on the conductive resin film 2 and the porous fiber film 3 contains a conductive material containing an ionic polymer is particularly preferable.

<Thermoplastic resin film>
The thermoplastic resin film is not particularly limited in material, thickness, size, shape, etc., and can be appropriately selected according to the purpose from known ones commonly used in heat-sensitive stencil printing masters. As the material, a thermoplastic resin is suitable, and examples thereof include polyester resin, polyamide resin, polyethylene resin, polypropylene resin, polyvinyl chloride resin, polyvinylidene chloride resin, vinyl chloride-vinylidene chloride copolymer, and the like. .
Examples of the polyester resin include a polyethylene terephthalate resin, a copolymer of ethylene terephthalate and ethylene isophthalate, a copolymer of hexamethylene terephthalate and cyclohexanedimethylene terephthalate, etc. From the viewpoint of increasing, a copolymer of ethylene terephthalate and ethylene isophthalate, and a copolymer of hexamethylene terephthalate and cyclohexanedimethylene terephthalate are particularly preferable.

  If necessary, the thermoplastic resin film includes a flame retardant, a heat stabilizer, an antioxidant, an ultraviolet absorber, an antistatic agent, a lubricant such as a pigment, a dye, a fatty acid ester, and a wax, and an antifoaming agent such as polysiloxane. An agent or the like can be blended. Furthermore, for the purpose of imparting easy slipperiness, for example, inorganic particles such as clay, mica, titanium oxide, calcium carbonate, kaolin, talc, wet silica, dry silica; organic particles containing acrylic acid, styrene and the like as constituent components Or a method of applying a surfactant.

As the thermoplastic resin film, a biaxially stretched resin film is preferable. Examples of the biaxially stretched resin film include a biaxially stretched polyester resin film, a biaxially stretched polyethylene resin film, and a biaxially stretched polypropylene resin film. Is mentioned.
The thickness of the thermoplastic resin film is preferably 0.1 to 5.0 μm, and more preferably 0.1 to 3.0 μm. When the thickness is less than 0.1 μm, the film formation stability may be deteriorated due to being too thin, and the printing durability may be lowered. When the thickness is more than 5.0 μm, the piercing property may be lowered.

<Porous support>
The porous support includes at least one of a porous resin film and a porous fiber film, and further includes other layers as necessary.

-Porous resin membrane-
As long as the porous resin film has a structure having a large number of voids inside and on the surface, the shape of the void, the average pore diameter, the porosity, etc. are not particularly limited and are appropriately selected according to the purpose. The shape of the gap is preferably a continuous structure in the thickness direction. For example, the voids are connected in an irregular rod shape, spherical shape, or branch shape (short structural units such as Japanese paper are intertwined. A thing having a complicated three-dimensional structure (not a combination of simple shapes formed by printing or the like), a structure resembling a so-called yarn string, a honeycomb-like structure, a honeycomb-like structure, or the like is preferable.
The average pore diameter of the voids is preferably 2 to 50 μm, more preferably 5 to 30 μm. When the average pore diameter is less than 2 μm, the ink permeability is poor, and therefore, if 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. In addition, the void ratio in the porous resin film is often lowered, and perforation by the thermal head is likely to be hindered. On the other hand, if the average pore diameter exceeds 50 μm, the effect of suppressing the ink by the porous resin film is lowered, and the ink between the printing drum and the film is excessively pushed out during printing, causing problems such as back stains and blurring. There is. In particular, when the average pore diameter of the voids in the porous resin film is 20 μm or less, the thicker the porous resin film layer, the more difficult it is for the printing ink to pass, so the thickness of this layer controls the amount of ink transferred to the printing paper. can do. If the thickness of the porous resin film is not uniform, uneven printing may occur. Therefore, it is desirable that the thickness is uniform.

2-100 micrometers is preferable and, as for the thickness of the said porous resin film, 5-50 micrometers is more preferable. When the thickness is less than 5 μm, the porous resin film hardly remains behind the perforated part after perforation by the thermal head, and the back stain of the printed matter easily occurs without controlling the ink transfer amount. Further, the effect of suppressing the ink transfer amount of the porous resin film is larger as the film is thicker, and the amount of ink transferred onto the paper during printing can be adjusted by the thickness of the porous resin film.
Density of the porous resin film is preferably usually 0.01 to 1 g / cm ^3, more preferably 0.1~0.7g / cm ^3. When the density is less than 0.01 g / cm ³ , the strength of the film is insufficient, and the film itself may be easily broken.
The adhesion amount of the porous resin film is preferably 0.1~35g / ^{m 2,} more preferably 0.5~25g / ^{m 2,} more preferably 1~11g / ^{m 2.} The increase in the adhesion amount hinders the passage of ink and deteriorates the image quality. If the amount is less than 0.1 g / m, it becomes difficult to control the amount of ink transfer. If the amount exceeds 35 g / m ² , the passage of the ink is obstructed. It may make the image worse.

  As a first method for forming a porous resin film having the above-described structure, for example, as disclosed in JP-A-10-24667, a good solvent and a poor solvent for the resin forming the porous resin film are used. The resin and a fluid containing a good solvent and a poor solvent for the resin are applied in a semi-precipitated state on a thermoplastic resin film and dried to form. The fluid containing this resin, its good solvent, and poor solvent has a three-dimensional network-like structure in which the good solvent evaporates first, the poor solvent increases relatively, the resin precipitates due to resin concentration, etc. Form a structure. In this first formation method, a porous resin film having a string-like structure is generally formed, and productivity can be increased by selecting a solvent that evaporates quickly, such as ether or acetone.

  The resin material constituting the porous resin film is not particularly limited and may be appropriately selected depending on the intended purpose. For example, polyvinyl acetate resin, polyvinyl butyral resin, vinyl chloride-vinyl acetate copolymer, vinyl chloride- Vinyl resins such as vinylidene chloride copolymers, vinyl chloride-acrylonitrile copolymers, styrene-acrylonitrile copolymers; polyamide resins such as polybutylene resins and nylons; polyphenylene oxide resins, (meth) acrylate resins, polycarbonate resins; acetylcellulose, acetylbutyl Examples thereof include cellulose derivatives such as cellulose and acetylpropylcellulose. These may be used individually by 1 type and may use 2 or more types together. Among these, a thermoplastic resin is preferably used in order to form a porous resin film having excellent ink permeability, which is an object of the present invention.

  The porous resin film may further contain, for example, a filler, an antistatic agent, a stick preventing agent, a surfactant, an antiseptic, an antifoaming agent, etc., as long as the purpose and effect of the present invention are not impaired. Can be added.

The filler is added to adjust the formation, strength, pore size, stiffness, etc. of the porous resin film. Here, the filler is a concept including pigments, powders, and fibrous substances, and among these, needle-like, plate-like, or fibrous fillers are particularly preferable.
Examples of the filler include mineral needle fillers such as magnesium silicate, sepiolite, potassium titanate, wollastonite, zonolite and gypsum fiber; artificial minerals such as non-oxide needle whiskers and double oxide whiskers Examples thereof include plate-like fillers such as mica, glass flake, and talc; natural or synthetic fibrous fillers such as carbon fiber, polyester fiber, glass fiber, vinylon fiber, nylon fiber, and acrylic fiber.
Examples of the pigment include organic polymer particles made of polyvinyl acetate resin, polyvinyl chloride resin, polymethyl acrylate resin, and the like; inorganic pigments such as carbon black, zinc oxide, titanium dioxide, calcium carbonate, and silica. These may be used individually by 1 type and may use 2 or more types together.
The amount of the filler added is preferably 5 to 200 parts by mass with respect to 100 parts by mass of the resin. When the added amount of the filler is less than 5 parts by mass, curling may easily occur, and when it exceeds 200 parts by mass, the strength of the porous resin film may be reduced.

  The second method for forming the porous resin film is used when the good solvent and the poor solvent of the resin constituting the porous resin film do not mix with each other. For example, it is disclosed in JP-A-11-23885. In this method, a fluid mainly composed of a W / O type (water-in-oil) emulsion is applied onto a thermoplastic resin film and dried to form a porous resin film. The porous resin film formed from this W / O type emulsion generally has a honeycomb-like structure and a honeycomb-like three-dimensional network structure. The porous resin film formed by the second forming method is formed by applying a fluid mainly composed of a W / O emulsion on a thermoplastic resin film and drying it. After the portion is dried, it becomes pores through which ink passes, and a resin in the solvent (which may contain additives such as fillers and emulsifiers) becomes a structure.

  There is no restriction | limiting in particular as said resin, According to the objective, it can select suitably, For example, acrylic resin, ester resin, urethane type resin, acetal type resin, olefin type resin, vinylidene chloride type resin, epoxy type Examples thereof include resins, amide resins, styrene resins, vinyl resins, cellulose derivatives, modified products thereof, and copolymers thereof, among which vinyl butyral resins and urethane resins are particularly preferable.

  For the formation of the W / O emulsion, a surfactant having a relatively strong lipophilic HLB of 2.5 to 6 is effective, but when a surfactant having an HLB of 8 to 20 is used in the aqueous phase, too. A more stable and uniform W / O emulsion can be obtained. The use of a polymeric surfactant is also one method for obtaining a more stable and uniform emulsion. In addition, addition of a thickener such as polyvinyl alcohol or polyacrylic acid to the aqueous system is effective for stabilizing the emulsion.

  In order to adjust the formation, strength, pore size, stiffness and the like of the porous resin film, an additive such as a filler can be further added to the porous resin film as necessary. Of these, needle-like, plate-like, or fibrous fillers are particularly preferred. In addition, as a filler, it can select suitably from the thing similar to the said 1st formation method.

The adhesion amount after drying of the porous resin film in the first and second forming methods is preferably 0.3 to 30 g / m ² . If it is less than 0.3 g / m ^{2, the} amount of ink adhesion may not be controlled, and the prints may be transferred. If the porous thin paper is not bonded to the opposite side of the porous resin film as the ink-sensitive support with an adhesive or the like, the master itself becomes weak and difficult to handle. The amount is more preferably 20 g / m ² or more. On the other hand, when the adhesion amount exceeds 30 g / m ² , the passage of ink is inhibited and the image becomes worse.

-Porous fiber membrane-
The porous fiber membrane is not particularly limited as to the material, size, structure, etc., and can be appropriately selected according to the purpose. Examples of the material include mineral fibers such as glass, sepiolite, and various metals. Animal fibers such as wool and silk; natural fibers such as cotton, manila hemp, mulberry, mitsumata and pulp; regenerated fibers such as sufu and rayon; synthetic fibers such as polyester, polyvinyl alcohol and acrylic; semisynthetic fibers such as carbon fibers; Examples include thin paper such as inorganic fibers having a whisker structure. Among these, those containing natural fibers are suitable.

  The porous fiber membrane can be expected to prevent problems such as strength, dimensional change due to moisture absorption, and strength reduction by using synthetic fibers formed of a synthetic resin such as polyester or acrylic. There is a desirable range for the basis weight and thickness, but the present invention is not limited thereto.

  Moreover, it is preferable that the said porous fiber membrane contains the composite fiber of a synthetic fiber and a natural fiber. In this case, cost reduction by using natural fibers is a significant merit. However, since there is a concern about strength reduction by combining natural fibers, the blending ratio within a range in which the influence of strength reduction can be ignored is preferably 95 to 30% for synthetic fibers and 5 to 70% for natural fibers, More preferably, the synthetic fiber is 95-60% and the natural fiber is 5-40%.

The thickness (for example, diameter), length, and shape of the fibrous material constituting the porous fiber membrane is not particularly limited, and is appropriately selected according to the perforated diameter of the thermoplastic resin film, the thickness of the film, and the like. The diameter (thickness) of the fibrous substance is preferably 20 μm or less, and more preferably 1 to 10 μm. If the diameter is less than 1 μm, the tensile strength may be weakened, and if it exceeds 20 μm, ink passage may be hindered and a white-out image due to fibers may occur.
The length of the fibrous substance is preferably 0.1 to 10 mm, and more preferably 1 to 6 mm. If the length of the fibrous material is less than 0.1 mm, the tensile strength may be weakened, and if it exceeds 10 mm, it may be difficult to uniformly disperse.

There is no restriction | limiting in particular in the basic weight of the said porous fiber membrane, According to the objective, it can select suitably, 1-20 g / m < ² > is preferable and 3-10 g / m < ² > is more preferable. When the basis weight exceeds 20 g / m ² , the ink permeability decreases and the image sharpness may decrease. When the basis weight is less than 1 g / m ² , sufficient strength as an ink-permeable support is obtained. It may not be possible.

  The porous fiber membrane may be a commercially available product or an appropriately formed one. In addition, there is no restriction | limiting in particular as a method of forming the said porous fiber membrane, According to the objective, it can select suitably, For example, it describes in Japanese Patent Publication No.49-18728, Japanese Patent Publication No.49-8809, etc. This method can be used.

<Conductive material>
The conductive material contains at least an ionic polymer, and further contains a surfactant or the like as necessary.

-Ionic polymer-
The ionic polymer is not particularly limited as long as the glass transition temperature (Tg) is 10 ° C. or higher, and can be appropriately selected according to the purpose. From the viewpoint of maintaining transportability, an anionic polymer is preferable.
The anionic polymer is not particularly limited, and examples thereof include an anionic acrylic polymer and a styrene acrylic polymer. Specific examples of these commercially available products include NK polymer WS-500 (manufactured by Shin Nakamura Kogyo Co., Ltd.), NK polymer WS-52-U (manufactured by Shin Nakamura Kogyo Co., Ltd.), and the like.
The anionic polymer preferably contains at least one of an alkali metal salt and an ammonium salt. By including at least one of the alkali metal salt and ammonium salt, ions can easily move, and an excellent antistatic function can be exhibited even in a completely dry state.
There is no restriction | limiting in particular as said alkali metal salt, Although it can select suitably according to the objective, For example, lithium salt, sodium salt, potassium salt, rubidium salt, cesium salt, etc. are mentioned.
Examples of the ammonium salt include ammonia, methylamine, ethylamine, n-butylamine, dimethylamine, diethylamine, dibutylamine, trimethylamine, triethylamine, tri-n-butylamine, dimethylmonoethanolamine, triethanolamine, dimethylstearylamine, And salts with methyldilaurylamine.
In the case of the alkali metal salt, the influence of ions follows the ionization tendency of the alkali metal, and the magnitude of the surface resistivity is rubidium ≦ potassium <sodium <cesium <lithium.
In the case of the ammonium salt, the surface resistivity value is triethanolamine <dimethylmonoethanolamine <triethylamine = ammonia, and the more the number of hydroxyalkyl groups in the nitrogen substituent, the smaller the surface resistivity value, and antistatic Improves.
The content of the ionic polymer in the conductive material is preferably 20% by mass or more.
The glass transition temperature (Tg) of the ionic polymer needs to be 10 ° C. or higher, and is preferably 40 ° C. or higher. When the glass transition temperature is less than 10 ° C., for example, blocking occurs when the heat-sensitive stencil master is rolled.
The method for analyzing that the ionic polymer is contained in the heat-sensitive stencil master is not particularly limited and may be appropriately selected depending on the intended purpose. For example, in a heat-sensitive stencil master Whether or not an ionic polymer is contained can be determined by measuring the surface resistance value of the conductive material application surface. Usually, an organic substance is an insulator, whereas an ionic polymer has conductivity. Therefore, since the surface resistance value varies depending on whether or not an ionic polymer is contained, it can be determined by measuring this.
As the analysis method, elemental analysis of the conductive material-coated surface is also effective from the viewpoint that the ionic polymer has conductivity. That is, an elemental analysis of the same surface is performed on a heat-sensitive stencil printing master that is not coated with a conductive material and a heat-sensitive stencil printing master that is coated with a conductive material. The presence or absence of a functional polymer can be determined. As the elemental analysis, it is also effective to detect an element contained only in the ionic polymer by conducting an elemental analysis of the ionic polymer and an elemental analysis of the conductive material excluding only the ionic polymer.

The ionic polymer may be further crosslinked to improve water resistance.
There is no restriction | limiting in particular as a crosslinking agent used for the said bridge | crosslinking, Although it can select suitably according to the objective, A water-soluble melamine resin is the most preferable from the point of reaction rate, a crosslinking density, and compatibility.
Suitable examples of the water-soluble melamine resin include N-methylol melamine, methoxymethyl melamine, and partially alkyl-modified butylated melamine. Among these, from the viewpoint of water solubility, N- Methylolated melamine is preferred.
The content of the crosslinking agent in the crosslinked ionic polymer is preferably 5 to 60% by mass, and more preferably 5 to 20% by mass.
Further, the crosslinking agent may be crosslinked in combination with a commonly used acid catalyst.
The acid catalyst is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include primary ammonium phosphate, ammonium chloride, and p-toluenesulfonic acid.
The content of the acid catalyst in the crosslinked ionic polymer is preferably 1 to 3% by mass.
A polymerization initiator can also be used.
The polymerization initiator is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include persulfates such as potassium persulfate, ammonium persulfate and sodium persulfate, hydrogen peroxide, benzoyl peroxide. And peroxides such as lauroyl peroxide, and azo compounds such as azoisobutyronitrile and azoisovaleronitrile.
The number average molecular weight of the ionic polymer crosslinked by the crosslinking agent or the like is preferably several million or more.
The polymerization method with the ionic polymer such as the crosslinking agent is not particularly limited and can be appropriately selected from known methods according to the purpose. For example, solution polymerization, emulsion polymerization, suspension polymerization, bulk Among these, solution polymerization and emulsion polymerization are preferable from the viewpoints of reactivity and stability.

-Surfactant-
The surfactant is not particularly limited and may be appropriately selected depending on the intended purpose. However, a low molecular surfactant having a molecular weight of 2000 or less is preferable, and examples thereof include nonionic surfactants and anionic surfactants. Suitable examples include agents and amphoteric surfactants. Among these, those that adjust the surface tension of an aqueous solution containing an ionic polymer to a desired value to promote wetting to a synthetic resin molded article are preferable. For example, when applied to a polyester film, the surface tension Is preferably 40 dyn / cm or less.
In addition, the surfactant has an index (HLB value) representing hydrophilicity and lipophilicity of preferably 9 or more, more preferably 10 or more, and most preferably 13 or more. If the HLB value is less than 9, the conductive material may gel after the addition of the low molecular weight activator.
Preferred specific examples of the surfactant satisfying the preferred value of HLB include, for example, polyoxyalkylene alkyl ether, polyoxyethylene alkyl phenyl ether, polyoxyethylene fatty acid ester, sorbitan fatty acid ester, glycerin fatty acid ester, fatty acid metal soap, Preferable examples include alkyl sulfonates and betaine surfactants.
Further, from the viewpoint of reducing the surface resistance value on the porous support side described later and improving the transportability, the nonionic surfactant, the anionic surfactant, the amphoteric surfactant, etc. Then, a nonionic surfactant is preferable.

  In addition, for the ionic polymer, for example, an ultraviolet absorber, a pigment, an organic filler, an inorganic filler, a lubricant, an antiblocking agent, and the like can be appropriately selected and used as long as the object of the present invention is not impaired. . Furthermore, for example, cationic polymers and nonionic polymers can be appropriately selected and used.

  The heat-sensitive stencil printing master of the present invention has a static contact angle of 5 to 5 in a 23 ° C.-50% RH (relative humidity, the same shall apply hereinafter) environment by adding the surfactant. The angle is preferably 70 °. If the static contact angle is less than 5 °, wetting is promoted too much and the surfactant may become excessive, and if it exceeds 70 °, wetting may not be promoted sufficiently.

There is no restriction | limiting in particular as the method of making the said electroconductive material contain in a porous support body, Although it can select suitably according to the objective, It is preferable to make it adhere to this porous support body.
The content (attachment amount) in a film (for example, a porous fiber film or a porous resin film) containing the conductive material to be attached needs to be 0.01 to 2.0 g / m ² , More preferably, it is 0.05-0.5 g / m < ² >. If the content is less than 0.01 g / m ^2, not completely neutralizing the static electricity generated at the time of conveyance, further becomes a conveyance failure due to insufficient stiffness is obtained, and when it exceeds 2.0 g / m ^2, The ink passage is hindered, resulting in an unclear image.
The method for measuring the dry adhesion amount is not particularly limited and can be appropriately selected depending on the purpose. For example, the total weight before coating the conductive material is measured, and the conductive material is used. When the total weight after coating is measured, the wet adhesion amount (g / m ² ) is obtained by dividing the difference between the total weight after coating and the total weight before coating by the total coating area. Then, a method of calculating the dry adhesion amount by multiplying the wet adhesion amount by the solid content of the coating solution (hereinafter simply referred to as “liquid reduction method”) can be mentioned.

There is no restriction | limiting in particular as said other layer, According to the objective, it can select suitably, For example, a heat-fusion prevention layer, an adhesive layer, etc. are mentioned.
The thermal fusion prevention layer is provided to prevent fusion at the time of perforation on one surface of the thermoplastic stencil master in contact with the thermal head of the thermosensitive stencil printing master.
The anti-fusing layer is composed of silicone oil, silicone resin, fluorine resin, surfactant, antistatic agent, heat-resistant agent, antioxidant, organic particle, inorganic particle, pigment, dispersion aid, preservative, antiseptic. It is desirable to provide a thin layer made of foaming agent or the like.
The thickness of the heat fusion preventing layer is preferably 0.005 to 0.4 μm, and more preferably 0.01 to 0.4 μm.
The method for forming the heat fusion prevention layer is not particularly limited, but it is preferable to apply a solution diluted with water, a solvent or the like using a roll coater, a gravure coater, a reverse coater, a bar coater or the like, and then dry.

The said adhesive layer is provided in order to adhere | attach a thermoplastic resin film and a porous support body as needed.
Although it does not specifically limit as an adhesive agent used for adhesion | attachment, For example, a vinyl acetate resin, an acrylic resin, a urethane resin, a polyester-type resin, an ultraviolet-ray / electron beam curable adhesive agent etc. are mentioned.

The surface resistance value on the porous support side (contact surface side with the roll) in the heat-sensitive stencil printing master is preferably 1.0 × 10 ^{5 to} 1.0 × 10 ¹³ Ω in a 23 ° C.-50% RH environment. 1.0 × 10 ^{5 to} 1.0 × 10 ¹⁰ Ω is more preferable. When the surface resistance value exceeds 1.0 × 10 ¹³ Ω, conveyance failure may occur due to charging during conveyance in a printing machine, particularly in a low-temperature and low-humidity environment, and is less than 1.0 × 10 ^5. Even if the surface resistance value is decreased to a lower value by increasing the amount of the antistatic agent, the transportability on the printing press is hardly affected.

The bending stiffness (MD direction) in the heat-sensitive stencil printing master is a parameter that mainly means transportability and reduction in plate wrinkle, for example, using L & W STIFFNESS TESTER (manufactured by AB Lorentzen, 16-D), It can be measured by setting the bending angle = 30 ° and the bending length = 10 mm.
If the bending stiffness is low, poor conveyance is likely to occur, and further, plate wrinkles that occur when the master is applied to the drum after plate making are likely to occur. If it has a certain degree of bending rigidity, the above-mentioned problems do not occur, and normal conveyance and winding around the drum are performed. The range of bending stiffness having the above characteristics is preferably 20 to 110 mN, and more preferably 30 to 70 mN.

(Method for manufacturing a master for thermal stencil printing)
The manufacturing method of the master for heat-sensitive stencil printing of the present invention includes a porous support forming step and a porous fiber film forming step, and includes a conductive material coating step and, if necessary, other steps. Become.

-Porous support forming process-
The porous support forming step is a step of forming a porous support including at least one of a porous resin film and a porous fiber film on at least one surface of the thermoplastic resin film.
The porous resin film is formed by applying a porous resin film coating solution containing at least a resin on the thermoplastic resin film and drying it to form a porous resin film.
The porous resin film coating solution contains at least a resin and further contains other components as required, and is preferably a water-in-oil type.
As the method for forming the porous resin film, as described above, the first formation method (see Japanese Patent Laid-Open No. 10-24667), the second formation method (see Japanese Patent Laid-Open No. 11-23858), or the like. Is mentioned.

  The method for forming the porous fiber membrane is not particularly limited and may be appropriately selected depending on the purpose. As described above, it may be a paper-making paper obtained by wet-making short fibers, a nonwoven fabric or a woven fabric. It may be a screen basket or the like, and papermaking paper is preferably used from the viewpoint of productivity and cost.

-Conductive material application process-
The conductive material coating step is a step of coating a conductive material coating solution containing at least an ionic polymer on the surface of the porous support.
The conductive material coating solution is preferably water-based and has no flash point.
In recent years, there has been an increase in environmental protection, and it is desired that a thermal stencil printing master also reduce the environmental burden. In the present invention, in order to prevent air pollution and the like, it is possible to reduce the environmental burden by performing application with an aqueous composite material.

The viscosity of the conductive material coating solution is preferably 2 to 80 mPa · s, more preferably 5 to 40 mPa · s at 25 ° C. When the viscosity is less than 2 mPa · s, the required adhesion amount may not be sufficiently coated, and when it exceeds 80 mPa · s, the porous support may be pulled by the coating solution and the coating may not be continued. is there.
The pH of the conductive material coating solution is preferably 4-9.
As for the composite material containing the said electroconductive material, it is well-known that a stock solution is a strong acid. However, in consideration of the coating equipment, there is no problem with strong acid in equipment that has been subjected to rust prevention treatment, but it is desirable to use neutrality in other cases. In consideration of the above-mentioned corrosion aspect of the equipment, the pH of the coating solution is preferably 4 to 9, and more preferably 6 to 7.

  There is no restriction | limiting in particular as said other process, According to the objective, it can select suitably, For example, a stick prevention layer formation process etc. are mentioned.

  The method for laminating the porous fiber membrane and the film having the porous resin membrane is not particularly limited and can be appropriately selected depending on the purpose. For example, on one surface of the thermoplastic resin film It is preferable to apply a porous resin film coating liquid, and at least the outermost surface layer of the porous resin film is dried and formed into a film, and then bonded to the porous fiber film to which the adhesive is applied. If the porous fiber film is laminated before the porous resin film is formed, the formation of the porous resin film is hindered and a desired porous resin film cannot be obtained. Moreover, since there exists a possibility that the adhesive agent may block | close the hole of a porous resin film, it is more preferable to apply | coat to a porous fiber film.

The adhesive used when laminating (laminating) the porous fiber film and the film having the porous resin film has a high viscosity that does not block the pores of the porous resin film from the ink-permeable side. The viscosity until the adhesive is completely cured is preferably 100 mPa · s or more, more preferably 300 mPa · s or more at 25 ° C.
In this case, if a solvent-type adhesive is used as the adhesive, the porous resin film is eroded and the pores are blocked. Therefore, there is no solvent at least when the porous resin film and the porous fiber film are laminated. From this point, a solventless adhesive and an aqueous / emulsion adhesive are preferably used.

The method for applying the adhesive is not particularly limited and may be appropriately selected depending on the purpose. For example, (1) a coating solution diluted with an organic solvent such as ethyl acetate is applied to the porous fiber membrane. And a method of bonding with a porous resin film after drying, (2) a method of applying without solvent, and the like. The method is preferred.
The method for applying the adhesive is not particularly limited and may be appropriately selected depending on the purpose. For example, blade coating method, reverse roll coating method, gravure coating method, knife coating method, spray coating method, offset gravure Preferred examples include a coating method, a kiss coating method, a bar coating method, and the like.

  As the adhesive, a polyurethane-based adhesive is particularly preferable in order to obtain a predetermined adhesive strength and satisfy the above conditions. As the polyurethane-based adhesive, a solventless polyurethane adhesive capable of obtaining desired adhesive strength with a low adhesion amount is suitable. In the case of an aqueous / emulsion type polyurethane adhesive, a solventless polyurethane adhesive is preferably used from the viewpoint of expansion and contraction of the porous fiber film during application and deterioration of curling.

  The solventless polyurethane adhesive is not particularly limited and may be appropriately selected depending on the intended purpose. (1) One-component moisture-curable urethane prepolymer obtained by reaction of a polyol component and an isocyanate component, ( 2) A two-component curable adhesive that is divided into a polyol component and an isocyanate component.

  The polyol component is not particularly limited as long as it has a hydroxyl group at both ends and is a liquid, and can be appropriately selected according to the purpose. Examples thereof include polyether polyols and polyester polyols having hydroxyl groups at both ends. Can be mentioned.

  Examples of the isocyanate component include hexamethylene diisocyanate (HMDI), 2,4-diisocyanate-1-methylcyclohexane, 2,6-diisocyanate-1-methylcyclohexane, diisocyanate cyclobutane, tetramethylene diisocyanate, o-, m- and p-xylylene diisocyanate (XDI), dicyclohexylmethane diisocyanate, dimethyldicyclohexylmethane diisocyanate, hexahydrometaxylidene diisocyanate (HXDI), lysine diisocyanate alkyl ester (the alkyl part of the alkyl ester has 1 to 6 carbon atoms) Are preferred) aliphatic or cycloaliphatic diisocyanates; toluylene-2,4-diisocyanate (TD1), toluylene-2 6-diisocyanate, diphenylmethane-4,4′-diisocyanate (MDI), 3-methyldiphenylmethane-4,4′-diisocyanate, m- and p-phenylene diisocyanate, chlorophenylene-2,4-diisocyanate, naphthalene-1,5 -Aromatic diisocyanates such as diisocyanate, diphenyl-4,4'-diisocyanate, 3,3'-dimethyldiphenyl-4,4'-diisocyanate, 1,3,5-triisopropylbenzene-2,4-diisocyanate, diphenyl ether diisocyanate Etc. These may be used individually by 1 type and may use 2 or more types together.

  When a solventless polyurethane adhesive is applied to the porous fiber membrane, if the viscosity is too high, the fibers will drop and application failure will occur. Therefore, it is preferable to apply by lowering the viscosity by heating the roll. The viscosity of the solventless polyurethane adhesive is preferably 3000 cp or less, more preferably 300 to 1500 cp at 25 ° C. If the viscosity is less than 3000 cp, the opening may be blocked after being bonded to the porous resin film and ink permeability may be hindered, and the fiber layer is likely to fall off.

  When the solventless adhesive is used, curing is preferably performed for the purpose of promoting the reaction of the heat-sensitive stencil master wound in a roll. The curing temperature is preferably 50 ° C. or lower, more preferably 40 ° C. or lower. When the curing temperature exceeds 50 ° C., shrinkage of the thermoplastic resin film may occur and a curling problem may occur. The curing time is not particularly limited as long as the desired adhesive force can be obtained, and can be appropriately selected according to the purpose.

Unlike the conventional heat-sensitive stencil printing master (laminated product of thermoplastic resin film and porous fiber film), the adhesive adhesion amount does not need to consider the influence of perforation inhibition, so the desired adhesive strength is There is no particular limitation as long as it is a range that does not block the pores of the porous resin membrane and the porous fiber membrane, and can be appropriately selected according to the purpose, preferably 0.05 to 5.0 g / m ² , 0.1-3.0 g / m < ² > is more preferable.

  The heat-sensitive stencil master produced by the method for producing a heat-sensitive stencil master of the present invention does not lose the characteristics of excellent image quality and little set-off without losing the punching ability by the thermal head, There is no generation of jam or wrinkles on the drum due to static electricity in the printing press, and it is a high-quality one that can solve conventional problems.

  Examples of the present invention will be described below, but the present invention is not limited to these examples.

[Experiment 1]
(Example 1)
−Preparation of heat-sensitive stencil printing master−
First, the laminated body of the thermoplastic resin film and the porous resin film was produced as follows. Dissolve or disperse a porous resin film coating solution having the following composition, and slowly add 25.0 parts by weight of water containing 1% by mass of hydroxyethyl cellulose (HEC) to this to prepare a cloudy emulsion coating solution. did.
<Prescription of porous resin film coating solution>
Acetal resin (Sekisui Chemical Co., Ltd., KS-1) 2.5 parts by mass Talc 0.8 parts by mass Surfactant (Nikko Chemical Co., SO15U) 0 .1 part by mass-Surfactant (manufactured by Shin-Etsu Chemical Co., Ltd., KF6012) ... 0.1 part by mass -Surfactant (Johnson, J711) ... 0.2 parts by mass・ 43.0 parts by mass

Next, the obtained emulsion coating solution is applied to a biaxially stretched polyester film (thickness 2.0 μm, heat shrinkage rate at 100 ° C. × 3 minutes / horizontal = 11% / 12%) by a die coating method. It applied so that the adhesion amount after drying might be 3.0 g / m < ² >, it was made to dry and the laminated body of a thermoplastic resin film and a porous resin film was produced.
The thickness of the obtained porous resin film was 16 μm, and the average pore diameter of the porous resin film measured by the following method was 18.6 μm.
-Measurement of average pore diameter of porous resin membrane-
The average pore size of the porous resin film was measured after taking 10 photos with an electron microscope (100 times magnification) at any 10 locations on the porous resin film and taking the image information into a personal computer with a scanner. Then, it was binarized with image analysis software (freeware: Scion Image), and the aperture diameter was measured in terms of a circle from the area of the aperture. 1000 holes were randomly extracted from one photograph, and the average value of 10 sheets was determined as the average hole diameter.

<Preparation of porous fiber membrane>
First, 40% by mass of unstretched polyester fiber having a fineness of 0.2 decitex and a fiber length of 3 mm (manufactured by Teijin Co., Ltd., Tepyrus TK08PN), and a polyester binder fiber having a fineness of 1.5 decitex and a fiber length of 5 mm (sheath component: low melting point PET) , Heat melting temperature 110 ° C., core component: PET / Unitika Co., Ltd., Melty 4080) 60% by mass was mixed, and a porous fiber membrane was produced by a circular net paper machine.
The obtained porous fiber membrane had a basis weight of 7.5 g / m ² and a thickness of 28 μm.

Next, for the obtained porous fiber membrane, the conductive material A coating solution (solid content = 10.0% by mass) having the following composition was described in [0049] for antistatic and reinforcement of the porous support. It was applied and dried so that the dry adhesion amount (hereinafter simply referred to as “dry adhesion amount”) measured by the liquid loss method was 0.3 g / m ² . The conductive material A coating liquid is aqueous and has no flash point.
-Composition of conductive material A coating liquid-
-Styrene acrylic copolymer (WS-52-U, an anionic polymer manufactured by Shin-Nakamura Chemical Co., Ltd.) ... 100 parts by mass The pH of this conductive material A coating solution at 25 ° C is 6.1, The Tg of the anionic polymer was 68 ° C.

The laminate of the thermoplastic resin film and the porous resin film and the porous fiber film are laminated by applying a gravure coating with a urethane adhesive as a solvent and drying at 30 ° C. A laminate was obtained.
Next, a 1% by weight aqueous solution of water-soluble silicone oil (FZ2101, manufactured by Nihon Unicar Co., Ltd.) was applied to the surface of the thermoplastic resin film opposite to the porous resin film by a wire bar coating method and dried. Thus, a heat-sensitive stencil master as shown in FIG. 3 was produced. The obtained heat-sensitive stencil printing master was confirmed to contain an ionic polymer by the following method.

<< Method for confirming ionic polymer >>
In a heat-sensitive stencil printing master coated with the conductive material A coating liquid and a heat-sensitive stencil printing master coated with the conductive material A coating liquid, a porous X-ray analyzer (3270, manufactured by Rigaku Corporation) The detection amount of the main component element in the ionic polymer on the surface of the conductive fiber membrane was compared. In addition, when the main component elements in the ionic polymer were detected in advance, they were sulfur (S), sodium (Na), and bromine (Br).
As a result, in the heat-sensitive stencil printing master without applying the conductive material A coating liquid, S was 1000 cps, Na was 100 cps, and Br was 80 cps, whereas the heat-sensitive stencil coated with the conductive material A coating liquid. In the printing master, it was found that S was 5000 cps, Na was 800 cps, and Br was 900 cps, and the counts (cps) of S, Na, and Br were clearly increased.
Also in the following examples, as described above, the count numbers of S, Na, and Br in the heat-sensitive stencil printing master coated with the conductive material coating liquid are not coated with the conductive material coating liquid. It was confirmed that the ionic polymer was contained by observing an increase compared to the master for heat-sensitive stencil printing.

<Evaluation>
The obtained heat-sensitive stencil printing master was stored in a 50 ° C. environment for 1 week and then allowed to stand in a 23 ° C.-65% RH environment for 24 hours. When the master for heat-sensitive stencil printing was subjected to plate-making and printing continuously 50 times using a printing machine (Saterio 400, manufactured by Ricoh Co., Ltd.), problems such as winding due to static electricity were not recognized.
Further, the obtained heat-sensitive stencil printing master was subjected to humidity control for 12 hours in an environment of 23 ° C.-50% RH, and the surface resistance value of the porous fiber membrane surface using a surface resistance meter (manufactured by Agilent Technologies, 4339B). Was measured to be 4.5 × 10 ⁸ Ω.
Further, for the obtained thermal stencil printing master, when using L & W STIFFNESS TESTER (AB Lorentzen, 16-D), the bending angle was set to 30 °, the bending length was set to 10 mm, and the bending strength was measured. It was 45 mN in the MD direction.

(Comparative Example 1)
−Preparation of heat-sensitive stencil printing master−
In Example 1, instead of the conductive material A coating solution, a conductive material B coating solution (solid content = 9% by mass) having the following composition was applied so that the dry adhesion amount was 0.29 g / m ² . A heat-sensitive stencil printing master of Comparative Example 1 was produced in the same manner as Example 1 except that it was dried.
-Composition of conductive material B coating solution-
-Urethane polymer ... 7 parts by mass-Cationic surfactant (Elegan 264A; manufactured by NOF Corporation) ... 2 parts by mass-Water ... 91 parts by mass At 25 ° C of this conductive material B coating solution The pH of the polymer was 5.6, and the Tg of the urethane polymer was 210 ° C.

<Evaluation>
The obtained heat-sensitive stencil printing master was stored in a 50 ° C. environment for 1 week and then allowed to stand in a 23 ° C.-65% RH environment for 24 hours. When the master for heat-sensitive stencil printing was subjected to plate making and printing continuously using a printing machine (Saterio 400, manufactured by Ricoh Co., Ltd.) 50 times, winding due to static electricity occurred, resulting in poor conveyance.
Further, the obtained heat-sensitive stencil printing master was subjected to humidity control for 12 hours in an environment of 23 ° C.-50% RH, and the surface resistance value of the porous fiber membrane surface using a surface resistance meter (manufactured by Agilent Technologies, 4339B). Was 2.5 × 10 ¹³ Ω.
Further, for the obtained thermal stencil printing master, when using L & W STIFFNESS TESTER (AB Lorentzen, 16-D), the bending angle was set to 30 °, the bending length was set to 10 mm, and the bending strength was measured. It was 46 mN in the MD direction.

(Comparative Example 2)
−Preparation of heat-sensitive stencil printing master−
In Comparative Example 1, a coating liquid obtained by removing the cationic surfactant from the conductive material B coating liquid was applied so that the dry adhesion amount was 0.09 g / m ² and the pH at 25 ° C. was 4.1. A heat-sensitive stencil master for Comparative Example 2 was prepared in the same manner as Comparative Example 1 except that it was dried.

<Evaluation>
The obtained heat-sensitive stencil printing master was stored in a 50 ° C. environment for 1 week and then allowed to stand in a 23 ° C.-65% RH environment for 24 hours. When the master for heat-sensitive stencil printing was subjected to plate making and printing continuously using a printing machine (Saterio 400, manufactured by Ricoh Co., Ltd.) 50 times, winding due to static electricity occurred, resulting in poor conveyance.
Further, the obtained heat-sensitive stencil printing master was subjected to humidity control for 12 hours in an environment of 23 ° C.-50% RH, and the surface resistance value of the porous fiber membrane surface using a surface resistance meter (manufactured by Agilent Technologies, 4339B) Was 4.0 × 10 ¹³ Ω.
Further, for the obtained thermal stencil printing master, when using L & W STIFFNESS TESTER (AB Lorentzen, 16-D), the bending angle was set to 30 °, the bending length was set to 10 mm, and the bending strength was measured. It was 18 mN in the MD direction.

(Example 2)
−Preparation of heat-sensitive stencil printing master−
In Example 1, the porous fiber membrane was not provided, and the conductive material C coating liquid (solid content = 4.3 mass%) having the following composition was applied to the surface of the porous resin membrane with a dry adhesion amount of 0.15 g / m ² . A heat-sensitive stencil printing master of Example 2 as shown in FIG. 1 was produced in the same manner as in Example 1 except that it was coated and dried. The conductive material C coating solution is aqueous and has no flash point.
-Composition of conductive material C coating solution-
-Styrene acrylic copolymer (WS-52-U, manufactured by Shin-Nakamura Chemical Co., Ltd.) 43 parts by mass-Water ... 57 parts by mass of this conductive material C coating solution at 25 ° C The pH was 6.5 and the Tg of the anionic polymer was 68 ° C.

<Evaluation>
The obtained heat-sensitive stencil printing master was stored in a 50 ° C. environment for 1 week and then allowed to stand in a 23 ° C.-65% RH environment for 24 hours. When the master for heat-sensitive stencil printing was subjected to plate-making and printing continuously 50 times using a printing machine (Saterio 400, manufactured by Ricoh Co., Ltd.), problems such as winding due to static electricity were not recognized.
Further, the obtained heat-sensitive stencil printing master was subjected to humidity control for 12 hours in an environment of 23 ° C.-50% RH, and the surface resistance value of the surface of the porous resin film using a surface resistance meter (manufactured by Agilent Technologies, 4339B). Was 7.5 × 10 ⁹ Ω.
Further, for the obtained thermal stencil printing master, when using L & W STIFFNESS TESTER (AB Lorentzen, 16-D), the bending angle was set to 30 °, the bending length was set to 10 mm, and the bending strength was measured. It was 30 mN in the MD direction.

(Comparative Example 3)
-Production of heat-sensitive stencil master-
In Example 2, instead of the conductive material C coating solution, a conductive material D coating solution (solid content = 4% by mass) having the following composition was applied so that the dry adhesion amount was 0.15 g / m ² , A heat-sensitive stencil printing master of Comparative Example 3 was produced in the same manner as Example 2 except that it was dried.
-Composition of conductive material D coating solution-
-Urethane polymer: 4 parts by mass-Cationic surfactant (Elegan 264A; manufactured by NOF Corporation): 1 part by mass-Water: 95 parts by mass At 25 ° C of the conductive material D coating solution The pH of the polymer was 6.0, and the Tg of the urethane polymer was 210 ° C.

<Evaluation>
The obtained heat-sensitive stencil printing master was stored in a 50 ° C. environment for 1 week and then allowed to stand in a 23 ° C.-65% RH environment for 24 hours. When the master for heat-sensitive stencil printing was subjected to plate making and printing continuously using a printing machine (Saterio 400, manufactured by Ricoh Co., Ltd.) 50 times, winding due to static electricity occurred, resulting in poor conveyance.
Further, the obtained heat-sensitive stencil printing master was subjected to humidity control for 12 hours in an environment of 23 ° C.-50% RH, and the surface resistance value of the surface of the porous resin film using a surface resistance meter (manufactured by Agilent Technologies, 4339B). Was measured to be 7.0 × 10 ¹³ Ω.
Further, for the obtained thermal stencil printing master, when using L & W STIFFNESS TESTER (AB Lorentzen, 16-D), the bending angle was set to 30 °, the bending length was set to 10 mm, and the bending strength was measured. It was 32 mN in the MD direction.

(Example 3)
−Preparation of heat-sensitive stencil printing master−
In Example 1, a thermoplastic resin film and a porous fiber film were laminated, a porous resin film coating solution was applied onto the porous fiber film, and dried to form a porous resin film. The conductive material E coating liquid (solid content = 2.9 mass%) having the following composition was applied to the surface of the porous resin film so that the dry adhesion amount was 0.1 g / m ² and dried. A master for heat-sensitive stencil printing of Example 3 as shown in FIG. The conductive material E coating solution is aqueous and has no flash point.
-Composition of conductive material E coating solution-
-Styrene acrylic copolymer (WS-52-U, manufactured by Shin-Nakamura Chemical Co., Ltd.) ... 29 parts by mass-Water: 71 parts by mass This conductive material E coating solution at 25 ° C The pH was 6.8 and the Tg of the anionic polymer was 68 ° C.

<Evaluation>
The obtained heat-sensitive stencil printing master was stored in a 50 ° C. environment for 1 week and then allowed to stand in a 23 ° C.-65% RH environment for 24 hours. When the master for heat-sensitive stencil printing was subjected to plate-making and printing continuously 50 times using a printing machine (Saterio 400, manufactured by Ricoh Co., Ltd.), problems such as winding due to static electricity were not recognized.
Further, the obtained heat-sensitive stencil printing master was subjected to humidity control for 12 hours in an environment of 23 ° C.-50% RH, and the surface resistance value of the surface of the porous resin film using a surface resistance meter (manufactured by Agilent Technologies, 4339B). Was measured to be 8.0 × 10 ¹⁰ Ω.
Further, for the obtained thermal stencil printing master, when using L & W STIFFNESS TESTER (AB Lorentzen, 16-D), the bending angle was set to 30 °, the bending length was set to 10 mm, and the bending strength was measured. It was 40 mN in the MD direction.

(Comparative Example 4)
−Preparation of heat-sensitive stencil printing master−
In Example 3, instead of the conductive material E coating solution, a conductive material F coating solution (solid content = 3.75% by mass) having the following composition was applied so that the dry adhesion amount was 0.11 g / m ^2. Then, a heat-sensitive stencil master for Comparative Example 4 was produced in the same manner as in Example 3 except that it was dried.
-Composition of conductive material F coating solution-
-Urethane polymer ... 3 parts by mass-Cationic surfactant (Elegan 264A; manufactured by NOF Corporation) ... 0.75 parts by mass-Water ... 96.25 parts by mass This conductive material F coating solution The pH at 25 ° C. was 6.3, and the Tg of the urethane polymer was 210 ° C.

<Evaluation>
The obtained heat-sensitive stencil printing master was stored in a 50 ° C. environment for 1 week and then allowed to stand in a 23 ° C.-65% RH environment for 24 hours. When the master for heat-sensitive stencil printing was subjected to plate making and printing continuously using a printing machine (Saterio 400, manufactured by Ricoh Co., Ltd.) 50 times, winding due to static electricity occurred, resulting in poor conveyance.
Further, the obtained heat-sensitive stencil printing master was subjected to humidity control for 12 hours in an environment of 23 ° C.-50% RH, and the surface resistance value of the surface of the porous resin film using a surface resistance meter (manufactured by Agilent Technologies, 4339B). Was measured to be 9.0 × 10 ¹³ Ω.
Further, for the obtained thermal stencil printing master, when using L & W STIFFNESS TESTER (AB Lorentzen, 16-D), the bending angle was set to 30 °, the bending length was set to 10 mm, and the bending strength was measured. It was 41 mN in the MD direction.

Example 4
−Preparation of heat-sensitive stencil printing master−
In Example 1, the thermoplastic resin film and the porous fiber film were laminated without providing the porous resin film, and the conductive material G coating solution (solid content = 3) having the following composition was laminated on the surface of the porous fiber film. 2 mass%) was applied so that the dry adhesion amount was 0.1 g / m ² and dried to produce a heat-sensitive stencil printing master of Example 4 as shown in FIG. The conductive material G coating solution is aqueous and has no flash point.
-Composition of conductive material G coating solution-
-Styrene acrylic copolymer (WS-52-U, manufactured by Shin-Nakamura Chemical Co., Ltd.) ... 32 parts by mass-Water ... 68 parts by mass This conductive material G coating solution at 25 ° C The pH was 6.5 and the Tg of the anionic polymer was 68 ° C.

<Evaluation>
The obtained heat-sensitive stencil printing master was stored in a 50 ° C. environment for 1 week and then allowed to stand in a 23 ° C.-65% RH environment for 24 hours. When the master for heat-sensitive stencil printing was subjected to plate-making and printing continuously 50 times using a printing machine (Saterio 400, manufactured by Ricoh Co., Ltd.), problems such as winding due to static electricity were not recognized.
Further, the obtained heat-sensitive stencil printing master was subjected to humidity control for 12 hours in an environment of 23 ° C.-50% RH, and the surface resistance value of the porous fiber membrane surface using a surface resistance meter (manufactured by Agilent Technologies, 4339B). Was measured to be 8.0 × 10 ¹⁰ Ω.
Further, for the obtained thermal stencil printing master, when using L & W STIFFNESS TESTER (AB Lorentzen, 16-D), the bending angle was set to 30 °, the bending length was set to 10 mm, and the bending strength was measured. It was 40 mN in the MD direction.

(Comparative Example 5)
−Preparation of heat-sensitive stencil printing master−
In Example 4, instead of the conductive material G coating solution, a conductive material H coating solution (solid content = 3.75% by mass) having the following composition was applied so that the dry adhesion amount was 0.11 g / m ^2. Then, a heat-sensitive stencil master for Comparative Example 5 was produced in the same manner as in Example 4 except that it was dried.
-Composition of conductive material H coating solution-
-Urethane polymer ... 3 parts by mass-Cationic surfactant (Elegan 264A; manufactured by NOF Corporation) ... 0.75 parts by mass-Water ... 96.25 parts by mass This conductive material H coating solution The pH at 25 ° C. was 6.3, and the Tg of the urethane polymer was 210 ° C.

<Evaluation>
The obtained heat-sensitive stencil printing master was stored in a 50 ° C. environment for 1 week and then allowed to stand in a 23 ° C.-65% RH environment for 24 hours. When the master for heat-sensitive stencil printing was subjected to plate making and printing continuously using a printing machine (Saterio 400, manufactured by Ricoh Co., Ltd.) 50 times, winding due to static electricity occurred, resulting in poor conveyance.
Further, the obtained heat-sensitive stencil printing master was subjected to humidity control for 12 hours in an environment of 23 ° C.-50% RH, and the surface resistance value of the porous fiber membrane surface using a surface resistance meter (manufactured by Agilent Technologies, 4339B). Was measured to be 9.0 × 10 ¹³ Ω.
Further, for the obtained thermal stencil printing master, when using L & W STIFFNESS TESTER (AB Lorentzen, 16-D), the bending angle was set to 30 °, the bending length was set to 10 mm, and the bending strength was measured. It was 41 mN in the MD direction.

(Example 5)
−Preparation of heat-sensitive stencil printing master−
In Example 1, instead of the conductive material A coating solution, a conductive material I coating solution (solid content = 8% by mass) having the following composition was applied to a dry adhesion amount of 0.25 g / m ² and dried. A heat-sensitive stencil printing master of Example 5 was produced in the same manner as Example 1 except for the above. The conductive material I coating liquid is aqueous and has no flash point.
-Composition of conductive material I coating solution-
-Styrene acrylic copolymer (WS-52-U, an anionic polymer manufactured by Shin-Nakamura Chemical Co., Ltd.) ... 80 parts by mass-Water ... 20 parts by mass This conductive material I coating solution at 25 ° C The pH was 5.9 and the Tg of the anionic polymer was 68 ° C.

<Evaluation 1>
The obtained heat-sensitive stencil printing master was stored in a 50 ° C. environment for 1 week and then allowed to stand in a 23 ° C.-65% RH environment for 24 hours. When the master for heat-sensitive stencil printing was subjected to plate-making and printing continuously 50 times using a printing machine (Saterio 400, manufactured by Ricoh Co., Ltd.), problems such as winding due to static electricity were not recognized.
Further, the obtained heat-sensitive stencil printing master was subjected to humidity control for 12 hours in an environment of 23 ° C.-50% RH, and the surface resistance value of the porous fiber membrane surface using a surface resistance meter (manufactured by Agilent Technologies, 4339B). Was measured to be 9.0 × 10 ⁸ Ω.
Further, for the obtained thermal stencil printing master, when using L & W STIFFNESS TESTER (AB Lorentzen, 16-D), the bending angle was set to 30 °, the bending length was set to 10 mm, and the bending strength was measured. It was 43 mN in the MD direction.

<Evaluation 2>
In the anionic polymer used in Example 5, the anionic polymer was applied onto a PET film (thickness = 16 μm) using a smooth bar and dried. When elemental analysis (fluorescence X-ray analysis) of the sample surface was performed, a large amount of Na was detected. From this, it was found that the anionic polymer contains an alkali metal salt.

<Evaluation 3>
A small amount of a surfactant having various HLB values was added to the conductive material I coating liquid used in Example 5, and the liquid state was observed. As a result, when the HLB value was 8.5, gelation occurred after addition, and the coating solution could not be used. When the HLB value was 9.5, gelation did not occur after the addition, and the coating solution was not affected. Gelation did not occur after addition even at HLB value = 13.3. The results are shown in Table 1.

<Evaluation 4>
25 wt% of polyoxyalkylene alkyl ether (actinol B-7W, Matsumoto Yushi Seiyaku Co., Ltd., HLB value = 12.1) as a nonionic surfactant was added to the conductive material I coating solution used in Example 6. When the static contact angle with respect to the polyethylene terephthalate film was measured by a liquid suitability method, it was about 5 °. Further, when 0.04 mass% of the polyoxyalkylene alkyl ether was added, the static contact angle was about 65 °. Furthermore, when the polyoxyalkylene alkyl ether was not added, the static contact angle was about 80 °. For comparison, the static contact angle of pure water was 115 °. The results are shown in Table 2.

(Comparative Example 6)
In Example 5, instead of the conductive material I coating solution, a conductive material J coating solution (solid content = 7.7% by mass) having the following composition was applied so that the dry adhesion amount was 0.25 g / m ^2. Then, a heat-sensitive stencil printing master of Comparative Example 6 was produced in the same manner as in Example 5 except that it was dried.
-Composition of conductive material J coating solution-
-Urethane polymer ... 6 parts by mass-Cationic surfactant (Elegan 264A; manufactured by NOF Corporation) ... 1.7 parts by mass-Water ... 92.3 parts by mass This conductive material J coating solution The pH at 25 ° C. was 6.2, and the Tg of the urethane polymer was 210 ° C.

<Evaluation>
The obtained heat-sensitive stencil printing master was stored in a 50 ° C. environment for 1 week and then allowed to stand in a 23 ° C.-65% RH environment for 24 hours. When the master for heat-sensitive stencil printing was subjected to plate making and printing continuously using a printing machine (Saterio 400, manufactured by Ricoh Co., Ltd.) 50 times, winding due to static electricity occurred, resulting in poor conveyance.
Further, the obtained heat-sensitive stencil printing master was subjected to humidity control for 12 hours in an environment of 23 ° C.-50% RH, and the surface resistance value of the porous fiber membrane surface using a surface resistance meter (manufactured by Agilent Technologies, 4339B). Was measured to be 9.0 × 10 ¹³ Ω.
Further, for the obtained thermal stencil printing master, when using L & W STIFFNESS TESTER (AB Lorentzen, 16-D), the bending angle was set to 30 °, the bending length was set to 10 mm, and the bending strength was measured. It was 41 mN in the MD direction.

(Example 6)
−Preparation of heat-sensitive stencil printing master−
In Example 1, instead of the conductive material A coating solution, a conductive material K coating solution (solid content = 8.05 mass%) having the following composition was applied so that the dry adhesion amount was 0.25 g / m ^2. A heat-sensitive stencil master for Example 6 was prepared in the same manner as in Example 1 except that it was dried. The conductive material K coating solution is aqueous and has no flash point.
-Composition of conductive material K coating solution-
・ Styrene acrylic copolymer (WS-52-U, anionic polymer manufactured by Shin-Nakamura Chemical Co., Ltd.) 80 mass parts ・ Polyoxyalkylene alkyl ether (actinol B-7W, manufactured by Matsumoto Yushi Seiyaku Co., Ltd.) = About 12.1) 0.05 mass parts Water 199.55 mass parts The pH of the conductive material K coating solution at 25 ° C is 6.3, and the Tg of the anionic polymer is It was 68 ° C.

<Evaluation>
The obtained heat-sensitive stencil printing master was stored in a 50 ° C. environment for 1 week and then allowed to stand in a 23 ° C.-65% RH environment for 24 hours. When the master for thermosensitive stencil printing was subjected to plate making and printing continuously 50 times using a printing machine (Saterio 400, manufactured by Ricoh Co., Ltd.), no problems due to static electricity were observed.
Further, the obtained heat-sensitive stencil printing master was subjected to humidity control for 12 hours in an environment of 23 ° C.-50% RH, and the surface resistance value of the porous fiber membrane surface using a surface resistance meter (manufactured by Agilent Technologies, 4339B). Was 9.5 × 10 ⁷ Ω.
Further, for the obtained thermal stencil printing master, when using L & W STIFFNESS TESTER (AB Lorentzen, 16-D), the bending angle was set to 30 °, the bending length was set to 10 mm, and the bending strength was measured. It was 43 mN in the MD direction.

(Example 7)
−Preparation of heat-sensitive stencil printing master−
In Example 1, instead of the conductive material A coating solution, a conductive material L coating solution (solid content = 6.5% by mass) having the following composition was applied so that the dry adhesion amount was 0.3 g / m ^2. A heat-sensitive stencil master for Example 7 was prepared in the same manner as Example 1 except that it was dried. The conductive material L coating solution is water-based and has no flash point.
-Composition of conductive material L coating liquid-
-Styrene acrylic copolymer (WS-52-U, anionic polymer manufactured by Shin-Nakamura Chemical Co., Ltd.) ... 65 parts by mass-Polyoxyalkylene alkyl ether (actinol B-7W, manufactured by Matsumoto Yushi Seiyaku Co., Ltd.) = About 12.1) ... 0.01 parts by mass-Water ... 34.99 parts by mass The pH of the conductive material L coating solution at 25 ° C is 6.6, and the Tg of the anionic polymer is It was 68 ° C.

<Evaluation>
The obtained heat-sensitive stencil printing master was stored in a 50 ° C. environment for 1 week and then allowed to stand in a 23 ° C.-65% RH environment for 24 hours. When the master for thermosensitive stencil printing was subjected to plate making and printing continuously 50 times using a printing machine (Saterio 400, manufactured by Ricoh Co., Ltd.), no problems due to static electricity were observed.
Further, the obtained heat-sensitive stencil printing master was subjected to humidity control for 12 hours in an environment of 23 ° C.-50% RH, and the surface resistance value of the porous fiber membrane surface using a surface resistance meter (manufactured by Agilent Technologies, 4339B). Was measured to be 7.0 × 10 ⁷ Ω.
Further, for the obtained thermal stencil printing master, when using L & W STIFFNESS TESTER (AB Lorentzen, 16-D), the bending angle was set to 30 °, the bending length was set to 10 mm, and the bending strength was measured. It was 50 mN in the MD direction.

(Comparative Example 7)
Example 7 is the same as Example 7 except that the conductive material L coating solution was applied so that the dry adhesion amount was 0.005 g / m ² and the pH at 25 ° C. was 6.9 and dried. Similarly, a heat-sensitive stencil printing master of Comparative Example 7 was produced.

<Evaluation>
The obtained heat-sensitive stencil printing master was stored in a 50 ° C. environment for 1 week and then allowed to stand in a 23 ° C.-65% RH environment for 24 hours. When the master for heat-sensitive stencil printing was subjected to plate making and printing continuously using a printing machine (Saterio 400, manufactured by Ricoh Co., Ltd.) 50 times, winding due to static electricity occurred, resulting in poor conveyance.
Further, the obtained heat-sensitive stencil printing master was subjected to humidity control for 12 hours in an environment of 23 ° C.-50% RH, and the surface resistance value of the porous fiber membrane surface using a surface resistance meter (manufactured by Agilent Technologies, 4339B). Was measured to be 8.0 × 10 ¹³ Ω.
Further, for the obtained thermal stencil printing master, when using L & W STIFFNESS TESTER (AB Lorentzen, 16-D), the bending angle was set to 30 °, the bending length was set to 10 mm, and the bending strength was measured. It was 15 mN in the MD direction.

( Reference Example 8)
In Example 1, instead of the conductive material A coating solution, a conductive material α coating solution (solid content = 10% by mass) having the following composition was applied so that the dry adhesion amount was 0.3 g / m ² and dried. A heat-sensitive stencil printing master of Reference Example 8 was produced in the same manner as in Example 1 except that the above was performed. The conductive material α coating liquid is water-based and has no flash point.
-Composition of conductive material α coating solution-
-Acrylic cationic polymer (IN-197, manufactured by Takamatsu Yushi Seiyaku Co., Ltd.) ... 40 parts by mass-Water ... 60 parts by mass The pH of this conductive material L coating solution at 25 ° C is 5.9. The Tg of the anionic polymer was 59 ° C.

<Evaluation>
The obtained heat-sensitive stencil printing master was stored in a 50 ° C. environment for 1 week and then allowed to stand in a 23 ° C.-65% RH environment for 24 hours. When the master for heat-sensitive stencil printing was subjected to plate-making and printing continuously 50 times using a printing machine (Saterio 400, manufactured by Ricoh Co., Ltd.), problems such as winding due to static electricity were not recognized.
Further, the obtained heat-sensitive stencil printing master was subjected to humidity control for 12 hours in an environment of 23 ° C.-50% RH, and the surface resistance value of the porous fiber membrane surface using a surface resistance meter (manufactured by Agilent Technologies, 4339B). Was 5.3 × 10 ¹⁰ Ω.
Further, for the obtained thermal stencil printing master, when using L & W STIFFNESS TESTER (AB Lorentzen, 16-D), the bending angle was set to 30 °, the bending length was set to 10 mm, and the bending strength was measured. It was 47 mN in the MD direction.
For convenience, Table 3 summarizes the results of Examples 1-8 and Comparative Examples 1-7.

[Experiment 2]
Example 9
In Example 1, instead of the conductive material A coating solution, a conductive material M coating solution (solid content = 8.5% by mass) having the following composition was applied so that the dry adhesion amount was 0.25 g / m ^2. Then, a heat-sensitive stencil master for Example 9 was prepared in the same manner as Example 1 except that it was dried. The conductive material M coating solution is aqueous and has no flash point.
-Composition of conductive material M coating solution-
-Styrene acrylic copolymer (anionic polymer)-80 parts by mass-Polyoxyalkylene alkyl ether (actinol B-7W, manufactured by Matsumoto Yushi Seiyaku Co., Ltd. HLB value = approximately 12.1)-0.5 mass Part-Water ... 19.5 parts by mass The pH of the conductive material M coating solution at 25 ° C was 6.8, and the Tg of the anionic polymer was 55 ° C.

<Evaluation 1>
The obtained heat-sensitive stencil printing master was stored in a 50 ° C. environment for 1 week, and the heat-sensitive stencil printing master was subjected to plate-making and printing continuously 50 times using a printing machine (Saterio 400, manufactured by Ricoh Co., Ltd.). However, no malfunction due to static electricity was observed.
Moreover, when printing with a solid image using a master printing machine (Saterio 400, manufactured by Ricoh Co., Ltd.) for the thermal stencil printing, a good image was obtained. The results are shown in Table 4.

<Evaluation 2>
The obtained heat-sensitive stencil printing master was stored in a 50 ° C. environment for 1 week and then allowed to stand in a 23 ° C.-65% RH environment for 24 hours. When the master for heat-sensitive stencil printing was subjected to plate making using a printing machine (Satelio 400, manufactured by Ricoh Co., Ltd.) and printing continuously 50 times, occurrence of blocking was not observed, and normal conveyance and plate making were possible. . The results are shown in Table 5.

(Comparative Example 8)
In Example 1, instead of the conductive material A coating solution, a conductive material N coating solution (solid content = 10% by mass) having the following composition was applied so that the dry adhesion amount was 2.5 g / m ² , A heat-sensitive stencil printing master of Comparative Example 8 was produced in the same manner as Example 1 except that it was dried.
-Composition of conductive material N coating solution-
-Styrene acrylic copolymer (WS-52-U, anionic polymer manufactured by Shin-Nakamura Chemical Co., Ltd.) ... 500 parts by mass-Polyoxyalkylene alkyl ether (actinol B-7W, manufactured by Matsumoto Yushi Seiyaku Co., Ltd.) = About 12.1) ... 3.13 parts by mass The pH of the conductive material N coating solution at 25 ° C was 6.6, and the Tg of the anionic polymer was 68 ° C.

<Evaluation>
The obtained heat-sensitive stencil printing master was stored in a 50 ° C. environment for 1 week, and the heat-sensitive stencil printing master was subjected to plate-making and printing continuously 50 times using a printing machine (Saterio 400, manufactured by Ricoh Co., Ltd.). However, no malfunction due to static electricity was observed.
However, when printing with a solid image using a master printing machine (Saterio 400, manufactured by Ricoh Co., Ltd.) for the thermal stencil printing, white spots occurred frequently and a good image was not obtained. The results are shown in Table 4.

(Comparative Example 9)
In Example 1, instead of the conductive material A coating solution, a conductive material O coating solution (solid content = 1.61 mass%) having the following composition was applied so that the dry adhesion amount was 0.005 g / m ^2. Then, a heat-sensitive stencil master for Comparative Example 9 was produced in the same manner as in Example 1 except that it was dried.
-Composition of conductive material O coating liquid-
-Styrene acrylic copolymer (WS-52-U, manufactured by Shin-Nakamura Chemical Co., Ltd.) 1.6 parts by mass-Polyoxyalkylene alkyl ether (actinol B-7W, manufactured by Matsumoto Yushi Seiyaku Co., Ltd.) HLB value = about 12.1)... 0.01 part by mass Water ... 98.39 parts by mass The pH of the conductive material O coating liquid at 25 ° C. is 6.2, and the anionic polymer Tg was 68 ° C.

<Evaluation>
The obtained heat-sensitive stencil printing master was stored in a 50 ° C. environment for 1 week, and the heat-sensitive stencil printing master was subjected to plate-making and printing continuously 50 times using a printing machine (Saterio 400, manufactured by Ricoh Co., Ltd.). However, winding due to static electricity occurred, resulting in poor conveyance.
However, when printing with a solid image was performed using a master printing machine (Saterio 400, manufactured by Ricoh Co., Ltd.) for the thermal stencil printing, a good image was obtained. The results are shown in Table 4.

(Comparative Example 10)
In Example 1, instead of the conductive material A coating solution, a conductive material P coating solution (solid content = 8.5% by mass) having the following composition was applied so that the dry adhesion amount was 0.25 g / m ^2. Then, a heat-sensitive stencil master for Comparative Example 10 was produced in the same manner as in Example 1 except that it was dried.
-Composition of conductive material P coating liquid-
-Styrene acrylic copolymer (anionic polymer)-80 parts by mass-Polyoxyalkylene alkyl ether (Actinol B-7W, manufactured by Matsumoto Yushi Seiyaku Co., Ltd. HLB value = approximately 12.1)-0.5 mass Part-Water ... 19.5 parts by mass The Tg of the anionic polymer of this conductive material P coating solution was 3 ° C.

<Evaluation>
The obtained heat-sensitive stencil printing master was stored in a 50 ° C. environment for 1 week and then allowed to stand in a 23 ° C.-65% RH environment for 24 hours. When the master for heat-sensitive stencil printing was subjected to plate making using a printing machine (Saterio 400, manufactured by Ricoh Co., Ltd.) and printing continuously 50 times, conveyance failure occurred due to blocking, and normal plate making was not completed. confirmed. The results are shown in Table 5.

(Example 10)
−Preparation of heat-sensitive stencil printing master−
In Example 1, a heat-sensitive stencil printing master of Example 10 was produced in the same manner as in Example 1 except that the porous fiber membrane was changed as follows.
-Production of porous fiber membrane-
50% by mass of unstretched polyester fiber having a fineness of 0.2 decitex and a fiber length of 3 mm (manufactured by Teijin Co., Ltd., Tepyrus TK08PN), a polyester binder fiber having a fineness of 1.5 decitex and a fiber length of 5 mm (sheath component: low melting point PET, heat A melting point of 110 ° C. and a core component: PET / Unitika Co., Ltd., Melty 4080) were mixed in an amount of 50% by mass, and a porous fiber membrane was produced by a circular net paper machine.
The obtained porous fiber membrane had a basis weight of 7.5 g / m ² and a thickness of 30 μm.

<Evaluation>
The obtained heat-sensitive stencil printing master was stored in a 50 ° C. environment for 1 week and then allowed to stand in a 23 ° C.-65% RH environment for 24 hours. When the master for thermosensitive stencil printing was subjected to plate making and printing continuously 50 times using a printing machine (Saterio 400, manufactured by Ricoh Co., Ltd.), no problems due to static electricity were observed.
Moreover, when printing with a solid image using a master printing machine (Saterio 400, manufactured by Ricoh Co., Ltd.) for the thermal stencil printing, a good image was obtained.

(Example 11)
−Preparation of heat-sensitive stencil printing master−
In Example 1, a heat-sensitive stencil printing master of Example 11 was produced in the same manner as Example 1 except that the porous fiber membrane was changed as follows.
-Production of porous fiber membrane-
35% by mass of unstretched polyester fiber having a fineness of 0.2 decitex and a fiber length of 3 mm (manufactured by Teijin Co., Ltd., Tepyrus TK08PN), a polyester binder fiber having a fineness of 1.5 decitex and a fiber length of 5 mm (sheath component: low melting point PET, heat Melting temperature 110 ° C., core component: PET / Unitika Co., Ltd., Melty 4080) 15% by mass, and 50% by mass of Manila hemp were further mixed, and a porous fiber membrane was obtained with a circular net paper machine. The obtained porous fiber membrane had a basis weight of 8.5 g / m ² and a thickness of 33 μm.

<Evaluation>
The obtained heat-sensitive stencil printing master was stored in a 50 ° C. environment for 1 week and then allowed to stand in a 23 ° C.-65% RH environment for 24 hours. When the master for thermosensitive stencil printing was subjected to plate making and printing continuously 50 times using a printing machine (Saterio 400, manufactured by Ricoh Co., Ltd.), no problems due to static electricity were observed.
Moreover, when printing with a solid image using a master printing machine (Saterio 400, manufactured by Ricoh Co., Ltd.) for the thermal stencil printing, a good image was obtained.

(Example 12)
−Preparation of heat-sensitive stencil printing master−
In Example 1, the heat-sensitive stencil printing of Example 12 was carried out in the same manner as in Example 1 except that the conductive material A coating solution was applied so that the dry adhesion amount was 0.15 g / m ² and dried. A master was prepared.

<Evaluation>
The obtained heat-sensitive stencil printing master was stored in a 50 ° C. environment for 1 week and then allowed to stand in a 23 ° C.-65% RH environment for 24 hours. When the master for thermosensitive stencil printing was subjected to plate making and printing continuously 50 times using a printing machine (Saterio 400, manufactured by Ricoh Co., Ltd.), no problems due to static electricity were observed.
Further, for the obtained thermal stencil printing master, when using L & W STIFFNESS TESTER (AB Lorentzen, 16-D), the bending angle was set to 30 °, the bending length was set to 10 mm, and the bending strength was measured. It was 38 mN in the MD direction. The results are shown in Table 6.

(Comparative Example 11)
In Example 1, the heat-sensitive stencil printing of Comparative Example 11 was performed in the same manner as in Example 1 except that the conductive material A coating solution was applied so that the dry adhesion amount was 2.5 g / m ² and dried. A master was prepared.

<Evaluation>
The obtained heat-sensitive stencil printing master was stored in a 50 ° C. environment for 1 week and then allowed to stand in a 23 ° C.-65% RH environment for 24 hours. When the plate making and printing of the heat-sensitive stencil printing master were repeated 50 times continuously using a printing machine (Saterio 400, manufactured by Ricoh Co., Ltd.), the paper was too strong to cause a conveyance failure.
Further, for the obtained thermal stencil printing master, when using L & W STIFFNESS TESTER (AB Lorentzen, 16-D), the bending angle was set to 30 °, the bending length was set to 10 mm, and the bending strength was measured. It was 120 mN in the MD direction. The results are shown in Table 6.

(Comparative Example 12)
In Example 1, the heat-sensitive stencil printing of Comparative Example 12 was conducted in the same manner as in Example 1 except that the conductive material A coating solution was applied so that the dry adhesion amount was 0.005 g / m ² and dried. A master was prepared.

<Evaluation>
The obtained heat-sensitive stencil printing master was stored in a 50 ° C. environment for 1 week and then allowed to stand in a 23 ° C.-65% RH environment for 24 hours. When the plate for printing and printing of the heat-sensitive stencil printing master using a printing machine (Saterio 400, manufactured by Ricoh Co., Ltd.) was repeated 50 times continuously, the stiffness was too weak, resulting in poor conveyance.
Further, for the obtained thermal stencil printing master, when using L & W STIFFNESS TESTER (AB Lorentzen, 16-D), the bending angle was set to 30 °, the bending length was set to 10 mm, and the bending strength was measured. It was 18 mN in the MD direction. The results are shown in Table 6.

[Experiment 3]
When the liquid viscosity at 25 ° C. of the conductive material A coating liquid of Example 1 was 30 mPa · s, no particular problem occurred during coating on the porous support.
When the liquid viscosity at 25 ° C. of the conductive material A coating solution was 85 mPa · s, the porous support was pulled by the coating solution, and it was impossible to continue coating.
When the liquid viscosity at 25 ° C. of the conductive material was 1.3 mPa · s, the liquid viscosity was too low, and it was sometimes impossible to perform coating satisfying the required adhesion amount.
The results are shown in Table 7.

  The heat-sensitive stencil printing master of the present invention does not cause poor conveyance due to static electricity in the printing press and winding failure around the printing drum, has sufficient stiffness, has little deterioration in antistatic performance, and is water-based. Since it is a material, it has excellent environmental properties and is suitably used for stencil printing.

FIG. 1 is a schematic cross-sectional view showing an example of the master for thermal stencil printing of the present invention. FIG. 2 is a schematic cross-sectional view showing an example of the heat-sensitive stencil master of the present invention. FIG. 3 is a schematic cross-sectional view showing an example of the master for thermal stencil printing of the present invention. FIG. 4 is a schematic cross-sectional view showing an example of the heat-sensitive stencil master of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Thermoplastic resin film 2 Porous resin film 3 Porous fiber film 10 Porous support body

Claims (19)

A thermoplastic resin film, and a porous support including at least one of a porous resin film and a porous fiber film on at least one surface of the thermoplastic resin film, the porous support being And a conductive material having a dry adhesion amount of 0.01 to 2.0 g / m ² including at least a styrene acrylic copolymer as an anionic polymer having a Tg of 10 ° C. or higher. Master for thermal stencil printing. The outermost surface layer of the porous support is a porous resin film, and the porous resin film contains a styrene acrylic copolymer as an anionic polymer having a Tg of 10 ° C. or higher, and a dry adhesion amount is 0.01. The master for heat-sensitive stencil printing according to claim 1, comprising a conductive material of ˜2.0 g / m ² . The porous support has a porous resin membrane on a porous fiber membrane, and the porous resin membrane contains a styrene-acrylic copolymer as an anionic polymer having a Tg of 10 ° C. or higher. The master for heat-sensitive stencil printing according to any one of claims 1 to ² , comprising a conductive material having an amount of 0.01 to 2.0 g / m2. The outermost surface layer of the porous support is a porous fiber membrane, and the porous fiber membrane contains a styrene acrylic copolymer as an anionic polymer having a Tg of 10 ° C. or higher, and a dry adhesion amount is 0.01. The master for heat-sensitive stencil printing according to claim 1, comprising a conductive material of ˜2.0 g / m ² . The porous support has a porous fiber membrane on a porous resin membrane, and the porous fiber membrane contains a styrene acrylic copolymer as an anionic polymer having a Tg of 10 ° C. or higher. amount 0.01 to 2.0 g / ^{m 2} and is containing a conductive material according to claim 1 and 4 of any heat-sensitive stencil master according. The master for heat-sensitive stencil printing according to any one of claims 1 to 5, wherein the styrene acrylic copolymer as the anionic polymer contains an alkali metal salt. The master for heat-sensitive stencil printing according to any one of claims 1 to 6, wherein the conductive material contains a surfactant. The master for heat-sensitive stencil printing according to claim 7, wherein the surfactant is a nonionic surfactant. The heat-sensitive stencil master according to claim 8, wherein the nonionic surfactant is a polyoxyalkylene alkyl ether. The master for heat-sensitive stencil printing according to any one of claims 7 to 9, wherein the surfactant has an HLB value of 9 or more. The surface resistance value on the porous support side of the heat-sensitive stencil printing master is 1.0 × 10 ⁵ ~ 8.0 × 10 ¹⁰ The master for heat-sensitive stencil printing according to any one of claims 1 to 10, which is Ω. The master for thermal stencil printing according to any one of claims 1 to 11, wherein a conductive material is attached to a porous support. The master for heat-sensitive stencil printing according to any one of claims 1 to 12, wherein the porous fiber membrane contains a synthetic fiber. The heat-sensitive stencil printing master according to any one of claims 1 to 13, wherein the porous fiber membrane contains a composite fiber of a synthetic fiber and a natural fiber. The thermal stencil printing master according to any one of claims 1 to 14, wherein the bending stiffness in the thermal stencil printing master is 20 to 110 mN in the MD direction. A porous support forming step of forming a porous support comprising at least one of a porous resin film and a porous fiber film on at least one surface of the thermoplastic resin film, and on the surface of the porous support, A method for producing a master for heat-sensitive stencil printing, comprising: a conductive material coating step of coating a conductive material coating solution containing at least a styrene acrylic copolymer as an anionic polymer. The method for producing a master for heat-sensitive stencil printing according to claim 16, wherein the coating liquid for conductive material is water-based and has no flash point. The method for producing a master for heat-sensitive stencil printing according to any one of claims 16 to 17, wherein the pH of the coating liquid for conductive material is 4 to 9. The method for producing a master for heat-sensitive stencil printing according to any one of claims 16 to 18, wherein the coating liquid for conductive material has a static contact angle with respect to the polyethylene terephthalate film of 5 to 70 °.

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