JP2013111805A - Master for thermal stencil printing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a master for a thermal stencil printing which corresponds to a printer having a fine thermal head, has a high resolution, is superior in durability, and is at low cost.SOLUTION: The master for the thermal stencil printing includes: at least a thermoplastic resin film layer; an adhesive layer; and a porous fiber membrane layer. The master for the thermal stencil printing is characterized in that the adhesive layer includes a water-based polyisocyanate prepared by dispersing a polyisocyanate into water as a main component, and the porous fiber membrane layer is such a porous fiber membrane as only comprising a synthetic fiber.

Description

  The present invention relates to a heat-sensitive stencil printing master that is pierced and engraved with a thermal head or the like by flash irradiation or infrared irradiation using a halogen lamp, a xenon lamp, a flash bulb, or a laser beam.

Conventionally, as a master for heat-sensitive stencil printing, a porous support made of a thermoplastic resin film such as a polyester film or a vinylidene chloride film, a synthetic fiber, or a thin paper, a non-woven fabric, a wrinkle, etc. mixed with these is used. Those having a structure bonded with an adhesive are known (for example, Japanese Patent Application Laid-Open No. 51-2513 of Patent Document 1 and Japanese Patent Application Laid-Open No. 57-182495 of Patent Document 2).
In recent years, thermal heads have been made finer, and the size of one dot has been reduced, so that a support made of only synthetic fibers having a small fiber diameter has been used.

Several proposals have been made as adhesives for laminating a support and a thermoplastic resin film in the production of a heat-sensitive stencil master (Japanese Patent Publication No. 5-27556, Patent Document 4). Japanese Patent Publication No. 7-88499, Japanese Patent Publication No. 5-34155, Japanese Patent Publication No. 5-34156, Japanese Patent Publication No. 5-47707, Japanese Patent Publication No. 4-47707, and the like.
However, when applying an adhesive in these inventions, it is necessary to dissolve the adhesive in an organic solvent, or to apply by lowering the viscosity of the adhesive by heating, and not only the equipment becomes expensive when an organic solvent is used. There are problems that the synthetic fiber is eroded and the strength is lowered, and the residual solvent has an adverse effect such as curling and delamination.
In addition, in the hot melt method in which the viscosity of the adhesive is reduced by heating and applied, it is necessary to apply the adhesive to the support side in order to avoid shrinkage of the thermoplastic resin film due to heat. When using a support having a weak inter-fiber binding force, such as a support, there is a problem in that the fibers are peeled off by the adhesive application roller and the productivity is poor. Moreover, when the temperature is too high, there is a problem that the synthetic fiber is dissolved.
As a master for heat-sensitive stencil printing that solves these problems, the one disclosed in Japanese Patent No. 4549557 (P45495557) of Patent Document 8 can be cited. That is, in a heat-sensitive stencil printing master in which a thermoplastic resin film and a porous support composed only of synthetic fibers (herein referred to as a porous fiber film) are bonded, a urethane resin is dispersed in water. A master for heat-sensitive stencil printing, which is bonded using an adhesive mainly composed of a water-based urethane resin.
Certainly, the above-mentioned problem does not occur in this master, but the delamination (peeling) due to the low adhesive strength between the thermoplastic resin film and the porous fiber membrane is a result of further ongoing studies by the present inventors. As a result, it has been recognized as a new problem (see Comparative Example 1 described later).

  SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned disadvantages of the prior art and to provide a thermal stencil printing master that is high in image quality, excellent in durability, and low in cost, corresponding to a printing press having a fine thermal head. It is what.

  In order to achieve the above object, the present inventors have conducted extensive research focusing on water-based adhesives in order to bond a porous fiber film made of only synthetic fibers and a thermoplastic resin film without any problems. The above-mentioned problems can be solved by applying and bonding water-based polyisocyanate obtained by dispersing polyisocyanate in water, focusing on the adhesion site area between the fiber of the porous fiber membrane and the thermoplastic resin film surface. And the present invention has been completed.

The present invention includes the following means as characteristic means for solving the above problems.
(1) “A thermosensitive stencil master having at least a thermoplastic resin film layer, an adhesive layer, and a porous fiber membrane layer, wherein the adhesive layer is mainly composed of an aqueous polyisocyanate obtained by dispersing polyisocyanate in water. A heat-sensitive stencil printing master characterized in that the porous fiber membrane layer is a porous fiber membrane made only of synthetic fibers.
(2) “A thermosensitive stencil printing master having at least a thermoplastic resin film layer, a porous resin film layer, an adhesive layer, and a porous fiber film layer, wherein the porous resin film layer is formed on the thermoplastic resin film. The porous resin film layer forming fluid contains a resin, a good solvent and a poor solvent for the resin, and the adhesive layer is a polyisocyanate. A heat-sensitive stencil printing master characterized in that a water-based polyisocyanate obtained by dispersing water in water is used as a main component, and the porous fiber membrane layer is a porous fiber membrane made only of synthetic fibers. .
(3) “The master for heat-sensitive stencil printing according to (1) or (2) above, wherein a porous fiber film is laminated and bonded after drying the adhesive”.
(4) “The master for heat-sensitive stencil printing according to any one of (1) to (3) above, wherein the polyisocyanate is a self-emulsifying polyisocyanate”.
(5) "attached amount after drying of the ^adhesive, the above mode (1) to which is a range of ^{0.2g / m 2 ~1.0g / m 2} (4) to any one of Items The master for thermal stencil printing described.
(6) “The master for heat-sensitive stencil printing according to any one of (1) to (5) above, wherein the adhesive strength between layers is 2 N / m or more”.
(7) The above-mentioned items (1) to (3), wherein the Oken-type smoothness of the thermoplastic resin film on the side opposite to the surface on which the porous fiber film or the porous resin film is laminated is 5000 seconds or more. The heat-sensitive stencil printing master according to any one of items 6).
(8) “The master for heat-sensitive stencil printing according to any one of (1) to (7) above, wherein an adhesive is applied to the porous fiber membrane”.

As will be well understood from the following detailed and specific description, according to the present invention, on a thermosensitive stencil printing master or a thermoplastic resin film in which a thermoplastic resin film and a porous fiber film made of synthetic fiber are bonded. In the heat-sensitive stencil printing master in which the porous resin film formed on and the porous fiber film made of synthetic fiber are bonded, the main component is an aqueous polyisocyanate obtained by dispersing polyisocyanate in water as an adhesive. The excellent effect of being able to provide a master for thermal stencil printing with high image quality and excellent durability, even for a printing press having a fine thermal head, by bonding with one. Is demonstrated.
More specifically, since the adhesive is cured by a chemical reaction of polyisocyanate, sufficient adhesive strength is obtained between the thermoplastic resin film and the porous fiber film, and there is no problem of delamination (peeling). The master for printing is realized, and the porous resin film layer and the porous fiber film layer are laminated through the adhesive layer. A master for printing is realized. In addition, when the porous fiber membrane is laminated and bonded after the adhesive is dried, the polyisocyanate remains even in the dried state, so that high adhesive strength is obtained, and the adhesive is made of a porous support (porous In addition to being able to obtain high adhesive strength with a small amount of adhesive, a characteristic heat-sensitive stencil printing master with less image blanking during printing has been realized. Because the polyisocyanate is a self-emulsifying type polyisocyanate, it is difficult for the polyisocyanate to agglomerate when the adhesive is applied, so that no adhesive lump is formed, and a master for thermal stencil printing with less white spots during printing is obtained. In addition, if the adhesive amount is too small, the adhesive strength is insufficient and delamination is likely to occur. If the adhesive amount is too large, white spots are likely to occur during printing. Where, resulting deposition amount after drying of the adhesive, by a range of ^{0.1g / m 2 ~1.0g / m 2} , delamination hardly occurs, the image white spots with less thermal stencil master An extremely excellent effect is exhibited.
Furthermore, if the adhesion strength between layers is 2 N / m or more, a heat-sensitive stencil printing master without delamination can be obtained.
Here, the interlayer is between the thermoplastic resin film and the porous fiber film, between the thermoplastic resin film and the porous resin film, or between the porous resin film and the porous fiber film. When the adhesion strength between these layers is less than 2 N / m, delamination (delamination between layers) is likely to occur, which not only causes wrinkles but also causes problems such as elongation, peeling and tearing of the master during printing. is there. The upper limit of the adhesive strength is not particularly limited as long as ink passage is not inhibited, and can be appropriately selected according to the purpose.
And, the master whose Wangken-type smoothness of the thermoplastic resin film opposite to the surface on which the porous fiber film or porous resin film is laminated is 5000 seconds or more is excellent in thermal perforation by the thermal head and poor perforation. Less image white spots at the time of printing, and furthermore, the adhesive is applied to the porous fiber membrane, so that the area of the adhesive attached to the film is reduced, and the film perforation by the thermal head is inhibited. Since it hardly occurs, an extremely excellent effect is obtained in that a master for thermal stencil printing with less image blanking at the time of printing is obtained.

It is a schematic cross section which shows an example of the master for thermal stencil printing of this invention.

-Adhesive-
Hereinafter, the present invention will be described specifically and in detail.
Here, FIG. 1 is a schematic cross-sectional view showing an example of the master for thermal stencil printing of the present invention.
On the thermoplastic resin film (1), a porous support (4) having a porous resin film (2) and a porous fiber film (3) in this order is laminated to form a laminate (5). This is an example.
The adhesive used in producing the heat-sensitive stencil printing master of the present invention (hereinafter sometimes simply referred to as “master”) is mainly composed of an aqueous polyisocyanate obtained by dispersing polyisocyanate in water. is there.
The water-based polyisocyanate of the present invention is a polyisocyanate dispersed in water (so-called O / W emulsion). From the particle size, 0.001 μm or less is an aqueous solution, and 0.001 to 0.1 μm is a colloid. If the dispersion is 0.1 μm or more, it can be classified into three types of emulsions, but the state is not particularly limited.

  Examples of the polyisocyanate used in the present invention 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), and lysine diisocyanate alkyl esters (the alkyl ester has 1 to 6 alkyl moieties) An aliphatic or alicyclic diisocyanate such as 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-diisocyanate, diphenyl-4,4′-diisocyanate, 3,3′-dimethyldiphenyl-4,4′-diisocyanate, 1,3,5-triisopropylbenzene-2,4- Aromatic diisocyanates such as diisocyanates and diphenyl ether diisocyanates: and mixtures thereof are used.

The method for producing the water-based polyisocyanate includes a case where it is dispersed in water using an emulsifier and a case where this is not used, but it may be arbitrarily selected and is not particularly limited.
When an emulsifier is used, an aqueous urethane resin can be obtained by stirring the polyisocyanate and the aqueous emulsifier solution at high speed.
As the emulsifier, a strong hydrophilic anionic surfactant, nonionic surfactant, or the like is used, and a surface activity with an HLB value (Hydrophilic-Lyophilic Balance) of 11-20 indicating the balance between the hydrophilic group and the lipophilic group is used. When an agent is used, a stable emulsion can be obtained.
Examples of methods that do not use an emulsifier include a method in which a polyisocyanate having an average molecular weight of 8000 or less is dispersed in water as it is, or a method in which self-emulsification is performed.
Methods for self-emulsification include reacting a diisocyanate compound with polyisocyanate in a solvent to introduce an anionic hydrophilic group into the polymer chain, then adding water and distilling off the solvent, and a method through a sulfonation reaction However, it is not particularly limited.

The preferable viscosity range of the adhesive coating solution in the present invention is 200 cp to 2000 cp.
If the viscosity is lower than 200 cp, most of the applied adhesive penetrates into the porous support material or unnecessarily spreads over the entire surface of the thermoplastic resin film to be bonded, and the desired adhesive strength cannot be obtained. Sometimes. If the viscosity is higher than 2000 cp, the fiber of the porous fiber membrane may be pulled out during coating, or wrinkles may be generated in the thermoplastic resin film.
The method for applying the adhesive in the present invention is not particularly limited, but it is preferable to apply the diluted solution using a roll coater, gravure coater, reverse coater, bar coater or the like and dry it.
The aqueous isocyanate resin is preferably diluted with water alone, but a small amount of alcohol may be added to increase the drying efficiency. In any case, it is possible to avoid the fact that much of the applied adhesive does not stay in the bonding site area of the porous support material and is unnecessarily spread over the entire surface of the thermoplastic resin film to be bonded. Preferably, this can be adjusted by the kind and amount of the diluent, the coating solution viscosity, the coating means, the degree of drying, the coating amount described later, and the like.
Further, the surface on which the adhesive layer is formed may be a thermoplastic resin film surface, a porous support surface, or may be applied to both sides, but it is more preferable to apply an adhesive to the porous support surface. .

Coating amount after drying of the adhesive in the present invention in the range of 0.2g ^{/ m 2} ~1.0g ^/ m 2 is preferred. When the coating amount after drying is less than 0.2 g / m ² , the adhesiveness is lowered, and when it exceeds 1.0 g / m ² , perforation inhibition occurs.

-Crosslinking agent-
Moreover, a crosslinking agent can be added to the adhesive aqueous dispersion, and an antistatic agent or the like can be added as necessary.
As the crosslinking agent (a material containing at least two active hydrogen groups), a material suitable for the water-based urethane resin to be used, such as a blocked isocyanate, an epoxy-based resin, or a melamine-based resin can be selected.
Examples of the antistatic agent include cationic, anionic, nonionic, amphoteric surfactants, carbon, conductive materials, and the like, but are not particularly limited as long as they do not affect the dispersion state of the aqueous polyisocyanate. Not.

In the thermosensitive stencil printing master of the present invention, the Oken type smoothness of the thermoplastic resin film on the side opposite to the surface on which a porous support such as a porous resin film or a porous fiber film is laminated is 5000 seconds or more. preferable.
If the Oken type smoothness is less than 5000 seconds, the adhesion with the thermal head is lowered, and perforation defects are likely to occur.

  Next, as the thermoplastic resin film in the master of the present invention, conventionally known ones such as a thermoplastic resin film obtained from polyester, polyamide, polypropylene, polyethylene, polyvinyl chloride, polyvinylidene chloride or a copolymer thereof are used. However, a polyester film is particularly preferably used from the viewpoint of perforation sensitivity.

Preferred examples of the polyester used in the polyester film include polyethylene terephthalate, a copolymer of ethylene terephthalate and ethylene isophthalate, and a copolymer of hexamethylene terephthalate and cyclohexanedimethylene terephthalate.
In order to improve the perforation sensitivity, a copolymer of ethylene terephthalate and ethylene isophthalate, a copolymer of hexamethylene terephthalate and cyclohexane dimethylene terephthalate, and the like are particularly preferable.

-Thermoplastic resin film-
If necessary, the thermoplastic resin film in the master of the present invention includes an organic lubricant such as a flame retardant, a heat stabilizer, an antioxidant, an ultraviolet absorber, an antistatic agent, a pigment, a dye, a fatty acid ester, a wax, or a poly An antifoaming agent such as siloxane can be blended.
Furthermore, easy slipperiness can be imparted if necessary.
The slipperiness imparting method is not particularly limited. For example, clay, mica, titanium oxide, calcium carbonate, kaolin, talc, wet or dry silica and other inorganic particles, acrylic acids, styrene, etc. There are a method of blending molecular particles, a method using internal particles, a method of applying a surfactant, and the like.

The thickness of the thermoplastic resin film in the master of the present invention is usually preferably 0.5 μm to 5.0 μm, and more preferably 1.0 μm to 3.0 μm.
When the thickness exceeds 5.0 μm, the piercing property may be deteriorated. When the thickness is less than 0.5 μm, the film forming stability may be deteriorated or the printing durability may be deteriorated.

-Porous fiber membrane-
As the synthetic fiber in the master of the present invention, conventionally known fibers such as synthetic fibers obtained from polyester, polyamide, polyphenylene sulfide, polyacrylonitrile, polypropylene, polyethylene, or a copolymer thereof are used.
Moreover, you may use the binder fiber etc. which have a core-sheath structure.
These synthetic fibers may be used alone or in combination of two or more.
In the present invention, polyester fibers are particularly preferably used from the viewpoint of thermal stability during perforation, and at least 60 wt% or more is more preferably polyester fibers.

  Preferred examples of the polyester used for the polyester fiber include polyethylene terephthalate, polyethylene naphthalate, polycyclohexanedimethylene terephthalate, and a copolymer of ethylene terephthalate and ethylene isophthalate.

  These synthetic fiber raw materials may contain flame retardants, heat stabilizers, antioxidants, UV absorbers, antistatic agents, pigments, dyes, fatty acid esters, organic lubricants such as waxes, or polysiloxanes as necessary. A foaming agent can be blended.

The basis weight of the porous support in the present invention is usually preferably ^{3g / m 2 ~20g / m 2} , more preferably from ^{5g / m 2 ~15g / m 2} .
If the basis weight exceeds 20 g / m ² , the ink permeability decreases and the image sharpness decreases.
On the other hand, if the basis weight is less than 3 g / m ² , sufficient strength as a support may not be obtained.

  The porous support made of synthetic fibers in the master of the present invention may be a paper-making paper made of short fibers, a non-woven fabric or a woven fabric, a screen wrinkle, etc. Is more preferably used.

-Porous resin membrane-
The porous resin film in the present invention has a structure having a large number of voids inside and on the surface of the film, and the voids have a continuous structure in the thickness direction in the porous film from the viewpoint of ink permeability. Is desirable.

The structure of the porous resin film is connected in an irregular rod shape, spherical shape, or branch shape (short structural units such as Japanese paper are not intertwined, and a combination of simple shapes formed by printing etc. Suitable examples include those having a complicated three-dimensional structure, a structure resembling a so-called yarn string, a honeycomb-like structure, a honeycomb-like structure, and the like.
In the present invention, the average pore diameter of the porous resin film is generally 2 μm to 50 μm, preferably 5 μm to 30 μm. When the average pore diameter is less than 2 μm, ink permeability is poor. For this reason, if low-viscosity ink is used in order to obtain a sufficient amount of ink passing, a phenomenon occurs in which printing ink oozes out from the side portion of the printing drum or the back end of the wound master during printing or printing. 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, when the average pore diameter exceeds 50 μm, the ink suppression effect by the porous resin film is reduced, and the ink between the printing drum and the film is excessively pushed out during printing, causing problems such as back stains and blurring. To do. That is, if the average pore size is too small or too large, good print quality cannot be obtained. 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 layer is not uniform, uneven printing may occur. Therefore, it is desirable that the thickness is uniform.

The viscosity of the coating liquid for forming a porous film is preferably 50 cp to 2000 cp. If the viscosity is lower than 50 cp, flow tends to occur during film conveyance during mechanical coating, and normal porous resin film formation may be hindered. On the other hand, if it exceeds 2000 cp, the film tends to wrinkle due to resin shrinkage during drying, and the porosity of the porous resin film tends to be low, and the resulting film often has poor ink permeability. The adhesion amount of the coating solution before drying is preferably 100 g / m ² or less. If it exceeds 100 g / m ² , the liquid tends to flow in the drying process after coating, and normal porous resin film formation may be prevented. There is no particular problem if the coating amount before drying of the coating solution is 100 g / m ² or less, but it is preferably 10 g / m ² or more in order to form a porous resin film capable of controlling ink permeability.

The thickness of the porous resin film of the present invention is 2 μm to 100 μm, desirably 5 μm to 50 μm. When the thickness is less than 5 μm, the porous resin film hardly remains behind the perforated portion 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. The density of the porous resin film is usually ^{0.03g / m 3 ~0.8g / m 3} , preferably is ^{0.06g / m 3 ~0.4g / m 3} . When the density is less than 0.03 g / m ³ , the strength of the film is insufficient, and the film itself is easily broken. If it exceeds 0.8 g / m ³ , the ink permeability during printing will deteriorate.

Next, the formation method of the porous resin film of the master for heat-sensitive stencil printing of this invention is demonstrated.
For example, as disclosed in JP-A-10-24667, the first porous resin film formation method is a good solvent for a resin for forming a porous resin film (refers to a solvent capable of dissolving the resin). And a poor solvent (which means a solvent that does not substantially dissolve the resin and has an evaporation rate slower than the evaporation rate of the good solvent), and the good solvent and poor solvent for the resin. The fluid containing is 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 structure in which the good solvent evaporates first, the poor solvent increases relatively, the resin precipitates due to resin concentration, etc. Form a structure.
When one good solvent and one poor solvent are used, the boiling point of the good solvent must be relatively lower than the boiling point of the poor solvent. The selection of the good solvent and the poor solvent is arbitrary, but in general, a porous resin film having desired characteristics is easily formed when the difference in boiling points is 15 ° C. to 40 ° C. When the difference in boiling points is less than 10 ° C., the difference in evaporation time between the two solvents is small, and the formed film is unlikely to have a porous structure. When the boiling point of the poor solvent is too high, drying takes time and the productivity is poor. Therefore, the boiling point of the poor solvent is desirably 150 ° C. or lower.

The resin concentration in the coating solution is 5% to 30% although it varies depending on the material used. If it is less than 5%, the opening diameter tends to be too large, or uneven thickness of the porous resin film tends to occur. Conversely, if it exceeds 30%, it is difficult to form a porous resin film, or even if it is formed, the pore diameter becomes small and it is difficult to obtain desired characteristics. The size of the average pore diameter of the porous resin film is affected by the poor solvent in the atmosphere. Generally, the higher the ratio to the good solvent, the larger the amount of condensation and the larger the average pore diameter. Since the addition ratio of the poor solvent varies depending on the resin and the solvent, it is necessary to determine appropriately by experiment. Generally, the pore diameter of the porous resin film increases as the amount of the poor solvent added increases. If the amount of the poor solvent added is too large, the resin will precipitate and the coating solution will become unstable.
In this first forming 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 used for forming the porous resin film is not particularly limited and can be appropriately selected from known materials according to the purpose. For example, polyvinyl acetate resin, polyvinyl butyral resin, vinyl chloride- Vinyl resins such as vinyl acetate copolymer, vinyl chloride-vinylidene chloride copolymer, vinyl chloride-acrylonitrile copolymer, styrene-acrylonitrile copolymer; polyamide resins such as polybutylene resin and nylon; polyphenylene oxide resin, (meth) acrylic ester resin, polycarbonate Resins; Cellulose derivatives such as acetylcellulose, acetylbutylcellulose, acetylpropylcellulose, and the like. 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.
The filler is not particularly limited and can be appropriately selected from known ones according to the purpose. For example, minerals such as magnesium silicate, sepiolite, potassium titanate, wollastonite, zonolite, gypsum fiber, etc. Needle-like fillers; artificial mineral-type needle-like fillers such as non-oxide-type needle-like whiskers and double oxide-type whiskers; plate-like fillers such as mica, glass flakes, and talc; carbon fibers, polyester fibers, glass fibers, vinylon fibers, Examples thereof include natural or synthetic fibrous fillers such as nylon fibers and acrylic fibers.
There is no restriction | limiting in particular as said pigment, According to the objective, it can select suitably according to the objective, For example, the organic polymer particle which consists of polyvinyl acetate resin, polyvinyl chloride resin, polymethyl acrylate resin, etc .; Examples thereof include 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 forming the porous resin film do not mix with each other, and disclosed in, for example, JP-A-11-23585. 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 the ink passes, and a resin in the solvent (which may contain additives such as fillers and emulsifiers) becomes a structure.

  The resin is not particularly limited and may be appropriately selected from known ones according to the purpose. Examples thereof include acrylic resins, ester resins, urethane resins, acetal resins, olefin resins, and vinylidene chloride. Resin, epoxy resin, amide resin, styrene resin, vinyl resin, cellulose derivative, modified products thereof, or copolymers thereof. Among these, vinyl acetal resins, 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. Among these, needle-like, plate-like, or fibrous fillers are particularly preferable. In addition, as a filler, it can select suitably from the thing similar to the said 1st formation method.
In the second forming method, since the obtained porous resin film shape does not depend on the solubility of the resin, it is hardly affected by temperature and humidity, and the formed porous resin film shape has high reproducibility. Since the degree of freedom of formulation is high and the range in which the porous resin film can be formed is wide, it is easy to adjust the viscosity of the coating liquid by the ratio of the oil phase / water phase, the resin concentration, the resin molecular weight, and the like. In general, if the solid content concentration of the coating liquid for forming a porous resin film is the same, the viscosity of the coating liquid for forming a porous resin film becomes higher than that of the first forming method.

As the dried adhesion amount of the porous resin film in the first and second forming method, preferably 0.3 to 20 g / ^{m 2,} 0.5 to 10 g / ^{m 2} is more preferable. The accumulation amount is less than 0.3 g / m ^2, may setoff of printed matter is degraded without the amount of ink deposited is controlled, to inhibit the passage of the ink exceeds 20 g / m ² Image May get worse.

  As a method of applying the coating liquid for forming a porous resin film of the present invention to the thermoplastic resin film, conventionally used methods such as blades, transfer rolls, wire bars, reverse rolls, gravure, and dies can be used. There is no particular limitation.

  In heat-sensitive stencil printing masters in which porous fiber membranes are laminated on porous resin membranes, the ink is uniformly dispersed by the porous resin membranes, so that the print image quality is excellent and the stiffness and strength are enhanced by the porous fiber membranes. Is improved, and transportability and printing durability are also excellent.

  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, and more preferably 40 ° C. or lower. When the temperature of the curing exceeds 50 ° C., the thermoplastic resin film may shrink 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.

  The heat-sensitive stencil printing master of the present invention has a silicone oil, a silicone resin, a fluorine resin, a surfactant, an antistatic agent, a heat resistance to prevent fusion at the time of perforation on one side of the film to be in contact with the thermal head. It is desirable to provide a thin layer comprising an agent, an antioxidant, organic particles, inorganic particles, a pigment, a dispersion aid, an antiseptic, an antifoaming agent, and the like. The thickness of the thin layer for preventing fusion is preferably 0.005 μm to 0.4 μm, more preferably 0.01 μm to 0.2 μm.

  The method for providing a thin layer for preventing fusion in the heat-sensitive stencil master of the present invention is not particularly limited, but a solution diluted with water, a solvent, or the like is applied using a roll coater, gravure coater, reverse coater, bar coater or the like. It is preferable to dry.

In the present invention, the following method was adopted for measuring the characteristics of the master for thermal stencil printing.
[Characteristic measurement methods and evaluation criteria]
-Image quality-
The prepared master was supplied to Ricoh's Satellite A650 (thermal head resolution 600 dpi), and an original having a black solid of 50 mm × 50 mm was prepared by a thermal head type plate making method, and 100 sheets were printed at a standard speed. .
By visual judgment of the printed matter, a black solid portion with no white spots was evaluated as “A”, an inconspicuous one was evaluated as “◯”, a white portion with white spots but practically no problem was evaluated as “B”, and a white portion with white spots conspicuous was evaluated as “X”.

-Printing durability-
The prepared master is supplied to Ricoh's Satellite A650, and a thermal head type plate making method is used to make a plate with 6 points of characters and a black solid of 50 mm × 50 mm, printing 5000 sheets at a standard speed. It was.
A film having no film peeling (delamination) or master wrinkle was evaluated as “◯”, a film having these but having no problem in actual use was evaluated as “B”, and a film having film peeling or master wrinkle enough to affect the printed image was evaluated as “X”.

-Smoothness-
The Oken type smoothness is measured using a Oken type smoothness tester (Kumaya Riki Kogyo Co., Ltd., KY-55 type), and the sample is conditioned at 20 ° C. and 65% atmosphere for 24 hours. The measured values were averaged to obtain a measured value.

-Adhesive strength-
After cutting out the master for heat-sensitive stencil printing to a width of 38 mm, one end of the thermoplastic resin film and the porous fiber membrane are peeled off, the thermoplastic resin film side is fixed to a digital force gauge, and a 500 g weight is attached to the porous fiber membrane side. Connection. The force gauge peak value when the weight was dropped was read and converted into a meter width. Even when there is a porous resin film between the thermoplastic resin film and the porous fiber film as in the heat-sensitive stencil printing master of claim 2, no distinction is made by the presence of the porous resin film, and the thermoplastic resin film and Measurement was performed by peeling the porous fiber membrane side.

EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited to these examples. All parts shown below are based on weight.

[Example 1]
<Creation of laminate of thermoplastic resin film and porous resin film>
Polyvinyl acetal resin (Sekisui Chemical Co., Ltd. ESREC KS-1 weight average molecular weight: 27,000) 0.4 part polyvinyl acetal resin (Sekisui Chemical Co., Ltd. ESREC KS-3 weight average molecular weight: 108,000) 0. 6 parts talc (average particle size D50 SALD method: 4.4 um SK method: 3.8 um Nihon Talc Co., Ltd. Microace L-1) 1.0 part sorbitan fatty acid ester (sorbitan sesquioleate HLB: 3.7 Nikko Chemicals Co., Ltd.) Company SO-15) 0.1 part modified silicone oil (polyether modified silicone, Shin-Etsu Chemical Co., Ltd. KF6012) 0.1 part acrylic polymer O / W emulsion (weight average molecular weight: 100,000 to 200,000 average particle diameter: 0.09um Johnson Polymer Co., Ltd. Joncryl-711) 0. Dissolved or parts of ethyl acetate 27.6, was dispersed, with stirring it to obtain a porous resin film forming coating liquid was clouded by the slow addition of a 1% aqueous solution of 30 parts of HEC. The obtained coating solution is applied and dried with a die coater on a thermoplastic resin film (biaxially stretched polyester film having a thickness of 1.8 μm) in an atmosphere of 20 ° C. and 50% RH to form a porous resin film. It was wound up into a shape. The porous resin film adhesion amount on the film after drying is 1.6 g / m ² .

<Creation of porous fiber membrane>
By wet papermaking, polyester fiber (60 parts by weight) having a core-sheath structure with a fineness of 1.0 d and stretched polyester fiber (40 parts by weight) having a fineness of 0.3 d are heat-treated at a temperature of 120 ° C., and a basis weight of 7.0 g A porous fiber membrane having a thickness of 30.0 μm / m ² was obtained.
Sheath Polyethylene terephthalate Thermal melting temperature: 110 ° C
Core Polyethylene terephthalate Thermal melting temperature: 260 ° C

<Creation of master for thermal stencil printing>
A 50 wt% aqueous dispersion of dihydric alcohol-modified hexamethylene diisocyanate (self-emulsifying polyisocyanate average molecular weight 1000) is applied to the porous fiber membrane prepared above so that the coating amount after drying is 0.19 g / m ^2. The film was spin-coated with a roll coater and overlapped with the porous resin film side of the laminate of the thermoplastic resin film and the porous resin film prepared above to obtain a laminate. Next, a 5% toluene solution of silicone oil (SF8422 manufactured by Shin-Etsu Chemical Co., Ltd.) is applied to the side opposite to the surface of the thermoplastic resin film on which the porous resin film is laminated. The composition was cured at 30 ° C. for 3 days to obtain the heat-sensitive stencil printing master of the present invention. Incidentally, the adhesion amount of SF8422 after drying is 0.03 g / ^{m 2.}

[Example 2]
Adhesive Except for applying a 50 wt% aqueous dispersion of dihydric alcohol-modified hexamethylene diisocyanate (self-emulsifying type polyisocyanate average molecular weight 1000) to the porous fiber membrane so that the coating amount after drying is 0.40 g / m ^2. Obtained a heat-sensitive stencil printing master in the same manner as in Example 1.

[Example 3]
The coating amount after drying a 50 wt% aqueous dispersion of an adhesive divalent alcohol-modified hexamethylene diisocyanate (self-emulsifying type polyisocyanate average molecular weight 1000) on the porous fiber membrane of Example 1 is 0.40 g / m ^2. The film was roll-coated with a roll coater and superposed on a thermoplastic resin film (biaxially stretched polyester film having a thickness of 1.8 μm) to obtain a laminate. Next, a 5% toluene solution of silicone oil (SF8422 manufactured by Shin-Etsu Chemical Co., Ltd.) is applied to the side opposite to the side on which the porous fiber membrane of the thermoplastic resin film is laminated, wound up after gravure coating, The composition was cured at 30 ° C. for 3 days to obtain the heat-sensitive stencil printing master of the present invention. Incidentally, the adhesion amount of SF8422 after drying is 0.03 g / ^{m 2.}

[Example 4]
Adhesive, except that 50 wt% aqueous dispersion of dihydric alcohol-modified hexamethylene diisocyanate (self-emulsifying type polyisocyanate average molecular weight 1000) was applied to a porous fiber membrane so that the coating amount after drying was 1.02 g / m ^2. Obtained a heat-sensitive stencil printing master in the same manner as in Example 3.

[Example 5]
Adhesive After applying a 50 wt% aqueous dispersion of dihydric alcohol-modified hexamethylene diisocyanate (self-emulsifying type polyisocyanate average molecular weight 1000) to a porous fiber membrane so that the coating amount after drying is 0.40 g / m ^2. A master for thermal stencil printing was obtained in the same manner as in Example 3 except that this was dried and then superposed on the thermoplastic resin film.

[Example 6]
Adhesive to thermoplastic resin film (biaxially stretched polyester film with a thickness of 1.8 μm) 20 wt% aqueous dispersion of dihydric alcohol-modified hexamethylene diisocyanate (self-emulsifying type polyisocyanate average molecular weight 1000) The laminate was applied with a gravure coater so as to be 0.40 g / m ² and overlapped with the porous fiber membrane of Example 1. Next, a 5% toluene solution of silicone oil (SF8422 manufactured by Shin-Etsu Chemical Co., Ltd.) is applied to the side opposite to the side on which the porous fiber membrane of the thermoplastic resin film is laminated, wound up after gravure coating, The composition was cured at 30 ° C. for 3 days to obtain the heat-sensitive stencil printing master of the present invention. Incidentally, the adhesion amount of SF8422 after drying is 0.03 g / ^{m 2.}

[Comparative Example 1]
The porous fiber membrane of Example 1 was spin-coated with a roll coater so that the coating amount after drying a 40 wt% aqueous dispersion of the adhesive Adekabon titer HUX401 (manufactured by Asahi Denka Co., Ltd.) was 2.0 g / m ^2. And laminated with a thermoplastic resin film (biaxially stretched polyester film having a thickness of 1.8 μm) to obtain a laminate. Next, a 5% toluene solution of silicone oil (SF8422 manufactured by Shin-Etsu Chemical Co., Ltd.) is applied to the side opposite to the side on which the porous fiber membrane of the thermoplastic resin film is laminated, wound up after gravure coating, A master for thermal stencil printing was obtained. Incidentally, the adhesion amount of SF8422 after drying is 0.03 g / ^{m 2.}

[Example 7]
<Creation of laminate of thermoplastic resin film and porous resin film>
Polyvinyl butyral resin (Sekisui Chemical Co., Ltd. ESREC BHS Weight average molecular weight: 66,000) 1.5 parts talc (Nihon Talc Co., Ltd. Microace L-1) 0.5 parts sorbitan fatty acid ester (Nikko Chemicals Corporation SO- 15) 0.1 part modified silicone oil (Shin-Etsu Chemical Co., Ltd. KF6012) 0.1 part acrylic polymer O / W type emulsion (Johnson Polymer Co., Ltd. Joncryl-711) 0.2 parts or more in ethyl acetate 22.6 After dissolution and dispersion, 25 parts of a 1% aqueous solution of HEC was slowly added while stirring this to obtain a white turbid coating solution for forming a porous resin film. The obtained coating solution is applied and dried with a die coater on a thermoplastic resin film (biaxially stretched polyester film having a thickness of 1.8 μm) in an atmosphere of 20 ° C. and 50% RH to form a porous resin film. It was wound up into a shape. The porous resin film adhesion amount on the film after drying is 1.6 g / m ² .

<Creation of water-based polyisocyanate adhesive>
Toluylene-2,4-diisocyanate (average molecular weight 1000) 50 parts Surfactant TI-10 (Polyoxyethylene (20) sorbitan monoisostearate, HLB 15.0, Nippon Surfactant Industries) 1 part Water 49 parts An aqueous polyisocyanate adhesive was obtained.

<Creation of master for thermal stencil printing>
The adhesive was roll-coated with a roll coater so that the coating amount after drying was 0.4 g / m ^{2 on} the porous fiber membrane of Example 1, and the thermoplastic resin film prepared above and porous A laminated body was obtained by superposing the laminated body of the resin film on the porous resin film side. Next, a 5% toluene solution of silicone oil (SF8422 manufactured by Shin-Etsu Chemical Co., Ltd.) is applied to the side opposite to the surface of the thermoplastic resin film on which the porous resin film is laminated. The composition was cured at 30 ° C. for 3 days to obtain the heat-sensitive stencil printing master of the present invention. Incidentally, the adhesion amount of SF8422 after drying is 0.03 g / ^{m 2.}

[Example 8]
<Creation of laminate of thermoplastic resin film and porous resin film>
ABS resin (Electrochemical Industry GR3000 Vicat softening point (5 kg load): 95 ° C. Heat distortion temperature (18.6 kgf / cm ² ): 85 ° C.) 2.5 parts talc (Nippon Talc Co., Ltd. Microace L-1) 0. After 5 parts or more were dissolved and dispersed in 15 parts of acetone, 10 parts of IPA was slowly added while stirring this to obtain a cloudy coating solution for forming a porous resin film. The obtained coating solution is applied and dried with a die coater on a thermoplastic resin film (biaxially stretched polyester film having a thickness of 1.8 μm) in an atmosphere of 20 ° C. and 50% RH to form a porous resin film. It was wound up into a shape.
The porous resin film adhesion amount on the film after drying is 2.0 g / m ² .

<Creation of water-based polyisocyanate adhesive>
Diphenylmethane-4,4-diisocyanate (average molecular weight 1000) 50 parts Surfactant TI-10 (Polyoxyethylene (20) sorbitan monoisostearate, HLB 15.0, manufactured by Nippon Surfactant Kogyo Co., Ltd.) 1 part Water 49 parts or more The mixture was stirred and mixed to obtain an aqueous polyisocyanate adhesive.

<Creation of master for thermal stencil printing>
The adhesive is roll-coated with a roll coater so that the coating amount after drying on the porous fiber membrane of claim 1 is 0.4 g / m ^2, and the thermoplastic resin film and the porous material prepared above are porous. A laminated body was obtained by superposing the laminated body of the resin film on the porous resin film side. Next, a 5% toluene solution of silicone oil (SF8422 manufactured by Shin-Etsu Chemical Co., Ltd.) is applied to the side opposite to the surface of the thermoplastic resin film on which the porous resin film is laminated. The composition was cured at 30 ° C. for 3 days to obtain the heat-sensitive stencil printing master of the present invention. Incidentally, the adhesion amount of SF8422 after drying is 0.03 g / ^{m 2.}

The prepared heat-sensitive stencil printing master was evaluated by the method described above.
The results are shown in Table 1.

From this result, the following salient matters can be understood.
Example 1 Since the adhesive amount is small, the adhesive strength is low, and the heat-sensitive stencil master is slightly wrinkled during the printing durability test, but there is no problem in practical use. Since the porous fiber membrane is provided between the thermoplastic resin film and the porous fiber membrane, the image quality is good.
Example 2 By adjusting the adhesive adhesion amount, in addition to the high image quality of Example 1, excellent printing durability is obtained.
Example 3 A master for thermal stencil printing in which a thermoplastic resin film and a porous fiber film are laminated.
Example 4 Due to the large amount of adhesive, white spots are slightly seen in the image, but there is no problem in actual use.
Example 5 By laminating the thermoplastic resin film and the porous fiber film after drying the adhesive, the adhesive does not spread on the film, and the perforation inhibition by the adhesive is less than in Example 3. Image quality has been improved.
Example 6 A master for heat-sensitive stencil printing in which an adhesive was applied to a thermoplastic resin film. Although there is no problem in actual use, since the adhesive is applied to the entire film, the image quality is inferior compared with Example 3.
Comparative Example 1 Since the adhesive strength of the adhesive was low, the master was peeled off during the printing durability test even when the adhesive was applied so much that white spots appeared on the image, and the image was disturbed.
Example 7 An example in which a water-based polyisocyanate adhesive was prepared using a surfactant.
There are no problems as with self-emulsifying polyisocyanates.
Example 8 An example in which a water-based polyisocyanate adhesive was prepared using a surfactant.
There are no problems as with self-emulsifying polyisocyanates.

DESCRIPTION OF SYMBOLS 1 Thermoplastic resin film 2 Porous resin film 3 Porous fiber film 4 Porous support body 5 Laminated body

Japanese Patent Laid-Open No. 51-2513 JP-A-57-182495 Japanese Patent Publication No. 5-27556 Japanese Patent Publication No. 7-88499 Japanese Patent Publication No. 5-34155 Japanese Patent Publication No. 5-34156 JP-A-4-47707 Japanese Patent No. 4549557

Claims (8)

  A heat-sensitive stencil printing master having at least a thermoplastic resin film layer, an adhesive layer, and a porous fiber membrane layer, wherein the adhesive layer is mainly composed of an aqueous polyisocyanate obtained by dispersing polyisocyanate in water. And the porous fiber membrane layer is a porous fiber membrane made only of synthetic fibers.   A thermosensitive stencil printing master having at least a thermoplastic resin film layer, a porous resin film layer, an adhesive layer, and a porous fiber film layer, wherein the porous resin film layer is porous on the thermoplastic resin film. The resin film layer forming fluid is laminated, and the porous resin film layer forming fluid contains a resin and a good solvent and a poor solvent of the resin, and the adhesive layer disperses the polyisocyanate in water. A heat-sensitive stencil printing master characterized in that a water-based polyisocyanate is used as a main component, and the porous fiber membrane layer is a porous fiber membrane made only of synthetic fibers.   The heat-sensitive stencil master according to claim 1 or 2, wherein a porous fiber film is laminated and adhered after drying the adhesive.   The heat-sensitive stencil printing master according to any one of claims 1 to 3, wherein the polyisocyanate is a self-emulsifying polyisocyanate. Deposition amount after drying of the adhesive, 0.2 g / m 2 to 1.0 g ^/, characterized in that m is in the range of ² claims 1 to 4 of the heat-sensitive stencil master according to any one.   The heat-sensitive stencil printing master according to any one of claims 1 to 5, wherein the adhesive strength between the layers is 2 N / m or more.   7. The Oken type smoothness of the thermoplastic resin film on the side opposite to the surface on which the porous fiber film or the porous resin film is laminated is 5000 seconds or more, according to claim 1. Master for thermal stencil printing   The heat-sensitive stencil printing master according to any one of claims 1 to 7, wherein an adhesive is applied to the porous fiber membrane.

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