JPH09277734A - Original plate for heat-sensitive stencil printing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve hole formation performance by a thermal head or the like and printing clearness, particularly, printing-resistant properties thereby to eliminate curls, by constituting a porous supporting body of at least two layers of thermoplastic resin fibers and a thin sheet and, bonding a thermoplastic resin film and a supporting body layer without interposing an adhesive. SOLUTION: A porous supporting body is constituted of at least two supporting body layers of thermoplastic resin fibers and a thin sheet. In the supporting body layer of thermoplastic resin fibers, a binder or a fixing agent, etc., is not used, but the fibers mutually melt at interlacing point and form a net-like body. Particularly, a thin film is formed at a part of the melting part. Therefore, the fibers of the supporting body are not shrunken or untwined by an organic solvent or water, etc., included in a printing ink, thus maintaining superior shape stability and a uniform shape of holes on a film face. Moreover, no warping is brought about even after a plurality of sheets are printed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat-sensitive stencil sheet. More specifically, the present invention relates to a curl-free heat-sensitive stencil printing base paper which is excellent in printing durability and is a heat-sensitive stencil printing base paper which is perforated by a thermal head or a laser beam.

[0002]

2. Description of the Related Art As a base paper conventionally used for heat-sensitive stencil printing, a thermoplastic resin film such as an acrylonitrile film, a polyester film or a vinylidene chloride film is used, and a porous support having ink permeability is used with an adhesive or the like. It is known that they are pasted together. As the porous support, a thin paper made of natural fibers such as Manila hemp (for example, JP-B-55-47997) or a thin paper made by mixing natural fibers and synthetic fibers (for example, JP-A-59-
33196, JP-A-60-217197).
Etc. are known. However, since the thin paper mainly composed of natural fibers is thick and flat, the smoothness of the film surface is deteriorated due to the unevenness of the fibers, the adhesion with the thermal head is deteriorated, and the film after platemaking is There is a problem in terms of printing sharpness, such as unperforated portions or fibers perforating the perforated portion of the film, which hinders ink transmission and causes white spot defects. Further, the thin paper which is mainly composed of natural fibers has a drawback that it tends to absorb moisture and is liable to curl due to a dimensional change due to moisture absorption.

In order to improve these drawbacks, a base paper using a synthetic fiber such as polypropylene or polyester having a thin fiber diameter and a uniform cross-sectional shape as a support (for example, JP-B-63-5).
9394, JP-A-2-107488, JP-A-7-186565), and a thermoplastic resin stretched film and an ink-permeable porous support are bonded via a chemical fiber having a fineness of 1 denier or less. A heat-sensitive stencil printing base paper (JP-A-5-221175) and the like have been proposed. However, although the one using a synthetic fiber having a small fiber diameter as a support has improved printing clarity, it has a drawback that wrinkles are likely to occur on the base paper because the stiffness (rigidity) of the base paper is insufficient. was there. In addition, JP-A-5-2211
No. 75, which is adhered via a chemical fiber having a fineness of 1 denier or less, a fixing agent solution in which the chemical fiber is dispersed is applied to a support or a film surface by a coating device and then a solvent is used. The chemical fibers are fixed to the surface of the support or film by heating and scattering, and then the support and the film are bonded with an adhesive. There was a problem in printing durability since the film and the support were easily peeled off by the solvent.

[0004]

DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned drawbacks and provides a curl-free heat-sensitive stencil printing base paper which is excellent in perforation plate-making property by a thermal head or the like and printing sharpness, and particularly excellent in printing durability. The purpose is to do.

[0005]

In order to achieve the above object, the present inventors have found that the defects of conventional base papers can be improved by specifying the support structure of the base paper for heat-sensitive stencil, and completed the present invention. It is a thing.

That is, the present invention provides a base paper for heat-sensitive stencil printing comprising a thermoplastic resin film and a porous support, the porous support comprising a support layer (A) made of thermoplastic resin fibers and a thin paper. A heat-sensitive stencil printing base paper comprising at least two layers of a body layer (B) and a thermoplastic resin film and a support layer (A) which are adhered to each other without an adhesive. .

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION In the base paper of the present invention, the porous support comprises at least two layers of A / B, the support layer (A) is composed of a thermoplastic resin fiber, and the support layer (B) is It is made of thin paper.

The support layer (A) of the present invention is composed of thermoplastic resin fibers and does not use a binder, a fixing agent or the like,
Preferably, the fibers form a mesh-like body fused to each other at the entanglement points. Particularly preferably, a thin film is formed on a part of the fused portion. That is, the fibers of the support are directly fused to each other to form a reticulated body, so that the support fibers are not stretched or unraveled by the organic solvent or water contained in the printing ink and are excellent in morphological stability. Therefore, the perforated shape of the film surface can be maintained uniform, and even if a large number of sheets are printed, the printed matter is not distorted and printing durability is excellent.

The thermoplastic resin fibers of the support layer (A) of the present invention are composed of irregularly arranged fibers. When the support is observed in a plane, it means that the fibers are irregularly arranged.
A state in which fibers are two-dimensionally dispersed. The fibers used are preferably long fibers, more preferably continuous fibers, rather than short fibers. By constructing the support layer (A) with long fibers, the entanglement of the fibers is sufficient, so that the mesh body can be formed only by thermal bonding, and the support strength can be made stable. Printing durability is improved. The long fiber in the present invention means a fiber having a fiber length of at least 30 mm or more.

The cross-sectional shape of the fiber is not particularly limited,
A circular or elliptical shape is particularly preferable from the viewpoint of smoothness of the film surface.

As the support layer (A) of the present invention, a non-woven fabric is more preferably used from the viewpoint of controlling the fiber diameter and the basis weight.

The non-woven fabric can be produced by a direct melt spinning method such as a flash spinning method, a melt blow spinning method and a spun bond spinning method. For example, in the melt blow spinning method, when discharging the molten polymer from the spinneret,
Hot air is blown from the periphery of the die, the polymer discharged by the hot air is made finer, and then it is blown and collected on a net conveyor arranged at an appropriate position to form a web. The average diameter and basis weight of the obtained fibers are adjusted by changing the polymer discharge amount, the hot air blowing amount, the moving speed of the conveyor, and the like.

Similarly, in the spunbond method, the polymer discharged from the die is pulled by an air ejector, and the obtained filament is collided with a collision plate to open the fiber,
It is manufactured by collecting webs on a conveyor and forming a web. The fiber diameter and basis weight of the web can be adjusted by appropriately setting the polymer discharge amount, the ejector pulling speed, and the conveyor speed.

The thermoplastic resin fiber constituting the support layer (A) of the present invention preferably has an average fiber diameter of 10 μm or less, more preferably 8 μm or less, particularly preferably 6 μm or less. By setting the average diameter of the fibers to 10 μm or less, the smoothness of the film surface is remarkably improved, so that the adhesion to the thermal head is improved, and the base paper having excellent perforation plate-making properties can be obtained.

The fiber basis weight of the support layer (A) is preferably 1
It is 5 g / m ² or less, more preferably 10 g / m ² or less, and particularly preferably 8 g / m ² or less. Weight is 15
By setting the g / m ² or less, the ink permeability and the holding property are balanced, the printing sharpness is improved, and even if a large number of sheets are printed, the printed matter does not have ink bleeding or blurring and has high print quality. Can be obtained.

It is preferable that both the fiber diameter and the basis weight are small in terms of perforation property and printability, but the lower limit is 0.01 μm for the fiber diameter.
m, and the basis weight is 0.5 g / m ² .

As the thermoplastic resin fiber constituting the support layer (A) of the present invention, for example, polyester, polyamide, polyphenylene sulfide, polyacrylonitrile, polypropylene, polyethylene or a copolymer thereof is used. These thermoplastic resin fibers may be used alone or in combination of two or more. In the present invention, polyester resin fibers are particularly preferably used from the viewpoint of thermal stability during perforation.

Preferred examples of the polyester include polyethylene terephthalate, polyethylene naphthalate, polycyclohexane dimethylene terephthalate, and a copolymer of ethylene terephthalate and ethylene isophthalate. From the viewpoint of thermal dimensional stability during perforation, polyethylene terephthalate and polyethylene naphthalate are particularly preferable. If necessary, these polymers may include flame retardants, heat stabilizers, antioxidants, UV absorbers, antistatic agents, organic lubricants such as pigments, dyes, fatty acid esters and waxes, or defoaming agents such as polysiloxanes. It can be blended.

The support layer (A) of the present invention may be composed of core-sheath composite fibers. When the core-sheath structure composite fiber is used, the sheath component is preferably composed of a component having an affinity for the film. The component having an affinity with the support layer (A) refers to a component that has sufficient bonding force by means such as thermocompression bonding and does not easily peel off. Such components may be the same as the film. The melting point of the sheath component is preferably lower than that of the core component of the thermoplastic resin film and the composite fiber. For example, when a polyethylene terephthalate resin is used for the film, a copolyester having a lower melting point than the sheath component is preferably used as the sheath component, and a dicarboxylic acid such as isophthalic acid, adipic acid or dimer acid as the copolymer component, Examples thereof include low molecular weight glycols such as diethylene glycol and butanediol.

The core component of the composite fiber is not particularly limited as long as it does not melt during thermocompression bonding, and for example, polyethylene terephthalate is preferably used. The ratio of the sheath component is usually 5/95 in terms of the cross-sectional area ratio of the sheath component / core component.
A range of 50/50 is preferred.

The composite fiber can be produced by using a core-sheath composite spinning nozzle.

The crystallinity of the thermoplastic resin fiber of the support layer (A) of the present invention is preferably 10% or more, more preferably 15% or more, particularly preferably 20% or more. When the crystallinity is 10% or more, the heat resistance and strength of the support are stable and the base paper does not curl.

The support layer (B) of the present invention is a thin paper. The thin paper can be manufactured by making short fibers by a wet papermaking method. Fiber length is 3 to 30 mm
Is preferred. By setting the fiber length to 3 mm or more, a thin paper having stable strength can be obtained, and by setting the fiber length to 30 mm or less, a thin paper having good ink permeability can be obtained. The fibers used are Manila hemp, sisal hemp, etc. 10
It may be 0% natural fiber, may be used in combination with pulp such as mulberry or sanpei, and may be mixed with synthetic fiber such as vinyl fiber or polyester fiber. More preferably, a synthetic fiber mixed with 10 to 30% has stable strength.

The basis weight of the support layer (B) is preferably 2-1.
5 g / m ^2, more preferably from 5 to 10 g / m ^2.
The thickness is preferably 10 to 100 μm, more preferably 30 to 70 μm. By setting the basis weight to 2 g / m ² or more, a base paper with stable strength can be obtained,
When the amount is 15 g / m ² or less, the ink permeability is good. Further, when the thickness is 10 μm or more, a strong base paper can be obtained, and when the thickness is 100 μm or less, the ink holding property becomes good.

The total weight of the support layer (A) and the support layer (B) in the present invention is preferably 20 g / m ² or less, more preferably 15 g / m ² or less. By setting the total basis weight to 20 g / m ² or less, it is possible to obtain a base paper which has an excellent balance between ink permeability and holding property and excellent printing durability.

The weight per unit area of the support layer (A) and the support layer (B) can be set arbitrarily, but is usually 5/95 to.
The range of 95/5 is preferable, and more preferably 5/95 to
80/20, particularly preferably 5/95 to 50/50.

The fibers used for the support layers (A) and (B) in the present invention may be chemically treated with an acid, an alkali or the like on the surface of the fibers which are formed as necessary in order to impart affinity with ink. Corona treatment, low temperature plasma treatment, etc. may be performed. Further, an antistatic agent may be added to the fiber surface in order to impart antistatic property.

The thermoplastic resin film in the present invention is
For example, polyester, polyamide, polypropylene, polyethylene, polyvinyl chloride, polyvinylidene chloride or a copolymer thereof is used, and a polyester film is particularly preferably used from the viewpoint of perforation sensitivity.

The polyester used for the polyester film is preferably polyethylene terephthalate, a copolymer of ethylene terephthalate and ethylene isophthalate, a copolymer of hexamethylene terephthalate and cyclohexane dimethylene terephthalate, and the like. Particularly preferred for improving the perforation sensitivity are a copolymer of ethylene terephthalate and ethylene isophthalate, a copolymer of hexamethylene terephthalate and cyclohexane dimethylene terephthalate, and the like.

The thermoplastic resin film in the present invention is
Although it may be unstretched, normally, a uniaxially or biaxially stretched film is preferably used. These thermoplastic resin films can be manufactured by a T-die method, an inflation method or the like. For example, in the T-die method, an unstretched film can be produced by extruding a polymer onto a cast drum, and the unstretched film is supplied to heating rolls having different speeds and stretched in the longitudinal direction to form a uniaxially stretched film. A biaxially stretched film can be produced by producing the above, and if necessary, supplying it to a tenter or the like and transversely stretching. In this case, the thickness of the unstretched film can be adjusted by adjusting the slit width of the die, the discharge amount of the polymer, and the rotation speed of the cast drum, and the rotation speed of the heating roll group can be adjusted. By changing the setting width of the tenter, films having different thicknesses and stretch ratios can be produced.

The thickness of the thermoplastic resin film in the present invention is usually preferably 0.1 to 10 μm, more preferably 0.1 to 5 μm, and particularly preferably 0.1 to 2 μm.
m. By making the thickness of the film 10 μm or less, it is possible to obtain a base paper having excellent perforation properties, and by making the thickness of the film 0.1 μm or more, stable film formation and lamination with a support can be achieved. It can be carried out.

In the thermoplastic resin film of the present invention, if necessary, 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 or a wax, or An antifoaming agent such as polysiloxane can be blended.

Further, slipperiness can be imparted if necessary. The method for imparting slipperiness is not particularly limited, but examples thereof include clay, mica, titanium oxide, calcium carbonate, kaolin, talc, inorganic particles such as wet or dry silica, organic particles containing acrylic acid, styrene and the like as constituent components. And the like, a method using internal particles, a method of applying a surfactant, and the like.

The melting point of the thermoplastic resin film of the present invention is T
m1, the melting point of the thermoplastic resin fiber of the support layer (A) is Tm
When it is set to 2, Tm1 ≦ Tm2 is preferable. More preferably Tm2-Tm1 is 5 ° C or higher, and particularly preferably 1
0 ° C. or higher. By setting Tm1 ≦ Tm2, the support fibers are not thermally deformed even when the film is perforated, so that the base paper having excellent plate-making properties can be obtained. In addition,
When the support layer (A) is a core-sheath fiber, Tm2 is the melting point of the core component.

In the base paper of the present invention, it is important that the thermoplastic resin film and the support layer (A) are adhered to each other without an adhesive.

In order to bond the thermoplastic resin film and the support layer (A) without using an adhesive, it is preferable to directly heat bond the film and the support layer (A).

The method of heat bonding is not particularly limited, but a method using a heating roll is particularly preferable from the viewpoint of processability.

When the support layer (A) is a composite fiber having a core-sheath structure, it is usually carried out by a nip roll or the like which is a combination of a silicone rubber roll and a metal roll. The heat-bonding temperature and pressure are appropriately determined depending on the materials of the thermoplastic resin film and the support layer (A), but the temperature is usually a temperature not lower than the glass transition point and not higher than the melting point of the sheath component of the composite fiber. Is preferable, and the nip pressure is 0.1 to 10 k.
A range of g / cm ² is preferred.

In a preferred embodiment of the present invention, it is particularly preferable that the thermoplastic resin film and the support layer (A) are heat-bonded without using an adhesive and are co-stretched to be integrated. . Co-stretching means uniaxially or biaxially stretching in a state where an unstretched thermoplastic resin film and a support layer made of unstretched thermoplastic resin fibers are thermally bonded. For example, by heat-bonding a non-stretched thermoplastic resin film and a support layer in the form of a non-woven fabric made of non-stretched thermoplastic resin fibers, and supplying the film to a conventional biaxially stretched film forming machine, the film and the support layer A co-stretched laminate with (A) can be obtained. By using such a co-stretched laminate, the thermoplastic resin film and the support layer (A) are directly fixed to each other and integrated without using an adhesive. Further, at this time, the fibers of the support layer (A) are irregularly arranged and stretched in a state of being fused to each other at the entanglement points, so that a net-like body suitable as a porous support is formed. Therefore, the strength of the support is stable, and the structure has uniform ink permeability. In addition, since the film surface of the base paper also has extremely good smoothness,
Adhesion with the thermal head is good, and perforation sensitivity of the film is also good.

Furthermore, when the film and the support layer (A) are formed into a co-stretched laminate, the winding property and handling property are significantly better than those of the film alone. In the laminating step with (4), wrinkles do not occur or break, and a great advantage can be obtained in terms of processability.

The method of co-stretching the unstretched thermoplastic resin film and the unstretched thermoplastic resin fiber is not particularly limited, such as uniaxial stretching and biaxial stretching, but biaxial stretching is usually preferred. The biaxial stretching may be either sequential biaxial stretching or simultaneous biaxial stretching. In the case of sequential biaxial stretching, it is general to stretch in the longitudinal direction and then in the transverse direction, but the stretching may be reversed. The draw ratio is not particularly limited and is appropriately determined depending on the type of thermoplastic resin used, the perforation sensitivity required for the base paper, etc.
About twice is appropriate. Also, after biaxial stretching, longitudinal or horizontal,
Alternatively, it may be re-stretched simultaneously in the length and width directions.

Further, the co-stretched thermoplastic resin film and the support layer (A) are preferably heat-treated. The heat treatment temperature is not particularly limited and is appropriately determined depending on the type of thermoplastic resin used, but in the case of polyester resin, it is preferably 80 to 200 ° C.

The support layer (A) and the support layer (B) may be adhered by thermal adhesion, or may be adhered by using an adhesive as long as the ink permeability is not impaired. Examples of the adhesive include known hot melt type adhesives, emulsion latex type adhesives, solvent type adhesives, reaction curable type adhesives, ultraviolet ray or electron beam curable type adhesives and the like.

The Oken type smoothness of the film surface of the base paper of the present invention is preferably 2000 seconds or more, more preferably 3000 seconds or more, and particularly preferably 4000 seconds or more. By setting the smoothness to 2000 seconds or more, the adhesion between the film surface and the thermal head is improved, and the energy applied to the thermal head is effectively transmitted to the film. Plate making is possible.

On the film side of the base paper of the present invention,
It is preferable to apply a release agent to prevent sticking during punching. As the release agent, a conventionally known release agent such as silicone oil, silicone resin, fluorine resin, and surfactant can be used. Also, in the release agent,
Various additives such as antistatic agents, heat-resistant agents, antioxidants, organic particles, inorganic particles and pigments can be mixed and used together.

[0046]

[Characteristics measurement method]

(1) Average fiber diameter (μm) After sampling 10 arbitrary points of the support layer and performing an ion coating treatment, the sample was 1 times at a magnification of 2000 with an electron microscope.
0 photographs were taken, the diameter of any 20 fibers was measured per photograph, this was carried out for 10 photographs, the diameter of 200 fibers was measured in total, and the average value was calculated. .

(2) Evaluation of printability The prepared base paper was used as "Lisograph" G manufactured by Ideal Science Industry Co., Ltd.
It is supplied to R275 and the thermal head plate making method is used.
Character size 6-po to 10.5-po and ● (circle filled in black) with diameter of 1-15 mm,
Using a ruled line having a thickness of 0.5 to 2 mm as an original, an A4 size base paper was prepared. Printing was carried out using the plate-making master, and the plate-making property and printability were evaluated as follows.

<Plate-making property> The solid portion of the plate-made base paper was sampled, and the film surface was magnified 10 times with a scanning electron microscope.
Photographs were taken at 0 times, the number of perforations corresponding to 150 dots (10 in length × 15 in width) of the thermal head was counted, and the judgment was made as follows.

A sample having no number of unperforated holes was evaluated as ◯, a sample having 1 or more and less than 10 unperforated samples was evaluated as Δ, and a sample having 10 or more unperforated samples was evaluated as x.

<Printability> The black solid portion of the 100th printed sheet was measured for printing density by a Macbeth optical densitometer,
It was determined as follows.

When the density was 1.0 or more, it was ◯, and when the density was 0.
A value of 8 or more and less than 1.0 was evaluated as Δ, and a density of less than 0.8 was evaluated as x.

<Printing durability> Printing 1000 sheets,
The base paper after printing was visually confirmed and judged as follows.

The paper without any wrinkles, peeling, or tears on the base paper was evaluated as ◯, the paper with wrinkles on the base paper was rated as Δ, and the paper with peeling or tearing was evaluated as x.

(3) Curl The base paper was cut into a square of 10 cm on each side (diamonds whose vertices were in the longitudinal direction and the horizontal direction of the base paper), and the cut sample was placed on a flat surface for 24 hours in an atmosphere of 50 ° C. After standing, the height of each vertex was measured. When the maximum height was 5 mm or less, it was evaluated as ◯, when 5 to 20 mm was evaluated as Δ, and when it was 20 mm or more as ×.

[0055]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited thereto.

Example 1 Using a rectangular die having a hole diameter of 0.3 mm and 100 holes, a polyethylene terephthalate raw material ([η] = 0.63, Tm = 257 ° C.) was netted by a melt blow method at a die temperature of 290 ° C. It was spun on a conveyor to prepare an unstretched nonwoven fabric and wound into a roll.

Then, a copolymerized polyester resin raw material ([η] = 0.65, Tm = 19) comprising 80 mol% of ethylene terephthalate and 20 mol% of ethylene isophthalate.
8 ° C.) was extruded at a T die die temperature of 275 ° C. using an extruder and cast on a cooling drum to prepare an unstretched film.

The unstretched nonwoven fabric was superposed on the unstretched film, supplied to a longitudinal stretching machine composed of a plurality of heating roll groups, and thermocompression bonded at a roll temperature of 75 ° C. Then 9
After being stretched 3.5 times in the length direction between heating rolls at 0 ° C, it is fed into a tenter type transverse stretching machine and the ambient temperature is 95 ° C.
And stretched 3.7 times in the width direction, and further 12 inside the tenter.
It heat-processed at 0 degreeC, the polyester film and the support layer (A) were produced, and the co-stretched laminated body was produced, and it wound up in the shape of a roll. The thickness of the polyester film of the laminate is 1.6μ
m, the average diameter of the fibers of the support layer (A) was 4 μm, and the basis weight was 3 g / m ² . Further, when the support layer (A) was observed with a microscope (manufactured by KEYENCE CORPORATION) at a magnification of 500 times, a net-like body in which fibers were fused to each other was formed.

Next, as a support layer (B), Manila hemp 70
%, Polyester fiber 30%, areal weight 10 g / m ²
Was prepared and laminated with the support layer (A) of the laminate using a polyvinyl acetate resin as an adhesive. Finally, silicone oil was applied to the film surface to prepare a heat-sensitive stencil printing base paper.

The base paper was good in both plate making property and printability, and good in printing durability and curl.

Example 2 In Example 1, instead of the polyethylene terephthalate raw material, a copolymerized polyester resin raw material ([η] = 0.62, Tm = 235 ° C.) consisting of 90 mol% ethylene terephthalate and 10 mol% ethylene isophthalate. ) Was used in the same manner as above, except that the unstretched nonwoven fabric was prepared by the melt blow method, and wound into a roll.

Then, the unstretched film obtained in Example 1 and the unstretched non-woven fabric were overlaid and stretched in the length direction and the width direction under the same conditions as in Example 1 to stretch the polyester film and the support layer (A). ) Was produced. The film thickness of the laminate was 1.6 μm, the average diameter of the fibers of the support layer (A) was 5 μm, and the basis weight was 4 g / m ² . Further, the support layer (A) is a microscope (manufactured by KEYENCE CORPORATION).
When observed at a magnification of 500 times, a reticulated body in which the fibers were fused was formed.

Next, the thin paper used in Example 1 was used as a support layer (B), and the support layer (A) of the laminate was overlaid, and the temperature was set to 120 ° C. by a calendar roll composed of a metal roll and a hard rubber roll. , And heat-bonded at a pressure of 2 kgf / cm ² . Silicone oil was applied to the film surface to prepare a heat-sensitive stencil printing base paper.

The base paper was good in plate making property, good in printability, good in printing durability and curl.

Example 3 A polyethylene terephthalate raw material ([η] = 0.63, Tm = 257 ° C.) was spun bonded at a die temperature of 290 ° C. using a die having a hole diameter of 0.25 mm and 100 holes. It was spun at a pulling speed of 1200 m / min to prepare an unstretched nonwoven fabric and wound into a roll.

Then, in the same manner as in Example 1, under the same conditions as in Example 1, except that the unstretched film and the unstretched nonwoven fabric were overlapped and stretched 3 times in the longitudinal direction and 3.3 times in the transverse direction. A co-stretched laminate of the polyester film and the support layer (A) was produced. Then, the thin paper of Example 1 was used as a support layer (B), and a polyvinyl acetate resin was used as an adhesive to laminate with the support layer (A) of the laminate. Then, silicone oil was applied to the film surface to prepare a heat-sensitive stencil printing base paper. The base paper has a film thickness of 1.8 μm, the support layer (A) has an average fiber diameter of 8 μm, and a basis weight of 5 g / m ^2.
Met. Further, when the support layer (A) was observed with a microscope (manufactured by KEYENCE CORPORATION) at a magnification of 500 times, a net-like body in which fibers were fused to each other was formed.

The base paper had a plate making property, printability and printing durability of Δ, and a curl of ◯.

Example 4 A polyethylene terephthalate resin was used as the core component, and a copolymerized polyester resin composed of 80 mol% ethylene terephthalate and 20 mol% ethylene isophthalate was used as the sheath component. A concentric core-sheath composite fiber was produced using a composite spinning machine. (Core-sheath cross-sectional area ratio = 80: 20) was spun to prepare a non-woven fabric-like support layer (A) having a fiber diameter of 10 μm and a basis weight of 6 g / m ² . Next, a 1.8 μm-thick polyester film prepared in Example 1 and a thin paper as a support layer (B) were prepared. Next, by laminating the film / support layer (A) / support layer (B) in this order and applying a tension, a calender roll composed of a metal roll and a hard rubber roll was used.
Thermal bonding was performed at a temperature of 120 ° C. and a pressure of 2 kgf / cm ² . Finally, silicone oil was applied to the film surface to prepare a heat-sensitive stencil printing base paper. When the support layer (A) was observed with a microscope (manufactured by KEYENCE CORPORATION) at a magnification of 500 times, it was found that a reticulated body in which fibers were fused to each other was formed.

The base paper has a plate-making property ○, printability Δ, printing durability,
The curl was ○.

Comparative Example 1 The thin paper of Example 1 and a biaxially stretched polyester film having a thickness of 2 μm were bonded together with a polyvinyl acetate adhesive, and silicone oil was applied to the film surface to prepare a heat-sensitive stencil printing base paper. It was made.

The base paper had a platemaking property and printability of Δ, and printing durability and curl were both x.

Comparative Example 2 Silicone oil was applied to the film surface of a co-stretched laminate of the polyester film having a thickness of 1.6 μm prepared in Example 1 and the support layer (A) having an average fiber diameter of 4 μm and a basis weight of 3 g / m ^2. Was applied to prepare a heat-sensitive stencil printing base paper. When the support layer (A) was observed with a microscope (manufactured by KEYENCE CORPORATION) at a magnification of 500 times, it was found that a reticulated body in which fibers were fused to each other was formed.

The base paper was good in plate making property and printability, bad in printing durability, and good in curl.

Comparative Example 3 A polypropylene nonwoven fabric having an average fiber diameter of 3 μm and a basis weight of 7 g / m ² was produced by ordinary melt blow spinning, and was used as a support layer (A). The support layer (A) and a polyester film having a thickness of 2 μm were attached to each other with a polyvinyl acetate adhesive. Then, the fabric weight produced in Example 1 was 10 g / m ^2.
The thin paper of (1) was used as the support layer (B) and the support layer (A) was laminated with a polyvinyl acetate adhesive. Silicone oil was applied to the film surface to prepare a heat-sensitive stencil printing base paper. When the support layer (A) was observed with a microscope (manufactured by KEYENCE CORPORATION) at a magnification of 500 times, the fibers were entangled with each other to form a mesh, but evidence of fusion of the fibers was observed. There wasn't.

The base paper had a plate-making property and a printability of Δ, and printing durability and curl were both x.

Comparative Example 4 A spinning speed of 4500 m /
The polyethylene terephthalate resin raw material was spun out in minutes, and embossing was performed at a roll temperature of 200 ° C. to prepare a support layer (A) having a fiber diameter of 12 μm and a basis weight of 8 g / m ² . A polyester film having a thickness of 2 μm was attached to the support layer (A) with a polyvinyl acetate adhesive. Then, the thin paper having a basis weight of 10 g / m ² produced in Example 1 was used as a support layer (B) and laminated with the support layer (A) using a polyvinyl acetate adhesive. Silicone oil was applied to the film surface to prepare a heat-sensitive stencil printing base paper. When the support layer (A) was observed with a microscope (manufactured by KEYENCE CORPORATION) at a magnification of 500 times, the fibers showed a reticulated body, but only the embossed portion was fused and most of the fibers were fused. Fibers were not fused.

The base paper had a plate making property Δ, printability ×, printing durability × and curl was Δ.

Comparative Example 5 A polyethylene terephthalate fiber having a fiber diameter of 8 μm and a fiber length of 3 mm was prepared by mixing ethylene glycol diglycidyl ether and polyamidoamine in a weight ratio of 20:80 and dissolved in isopropyl alcohol. It is mixed in and coated on one side of the thin paper (support layer (B)) having a basis weight of 10 g / m ² of Example 1 with a gravure coater, and the solvent is scattered to give a fiber basis weight of 3 g / m ² and a fixing agent. A support layer (A) having a solid content of 1 g / m ² was laminated and fixed. Then, a polyester film having a thickness of 2 μm was attached to the surface of the support layer (A) with a polyvinyl acetate adhesive. Silicone oil was applied to the film surface to prepare a heat-sensitive stencil printing base paper.

The base paper was good in plate making, good in printability, good in printing durability x, and bad in curl.

[0080]

Since the base paper of the present invention is constructed as described above, it has the following effects.

(1) The film and the support are not separated from each other by the water in the printing ink or the organic solvent, and the printing durability is excellent.

(2) Since the thermoplastic resin fibers of the support layer (A) form a mesh-like body which is fused to each other without using a binder or a fixing agent, water in the printing ink, an organic solvent, etc. The fibers will not come loose due to
Excellent printing durability.

(3) Since the adhesive does not hinder the perforation of the film or the ink transmission, it is possible to obtain a printed matter having high definition and excellent sharpness.

(4) Since the thermoplastic resin fibers are arranged between the film and the thin paper and no adhesive is used on the film side, the base paper does not curl even if the temperature or humidity changes.

(5) Since the thermoplastic resin fibers having a thin fiber shape and uniform are arranged on the film surface, the adhesion with the thermal head is improved, and the plate making faithful to the original can be performed.

Claims (7)

[Claims] 1. A heat-sensitive stencil printing base paper comprising a thermoplastic resin film and a porous support, wherein the porous support is a support layer (A) made of thermoplastic resin fibers and a support layer (made of thin paper. A base paper for heat-sensitive stencil printing, comprising at least two layers of B), wherein the thermoplastic resin film and the support layer (A) are bonded together without an adhesive. 2. The thermoplastic resin fiber of the support layer (A) comprises:
The base paper for heat-sensitive stencil printing according to claim 1, which is formed by forming a net-like body in which fibers are fused together. 3. The thermoplastic resin fiber of the support layer (A) is
The heat-sensitive stencil printing base paper according to claim 1 or 2, which is a fiber having an average fiber diameter of 10 µm or less. 4. The base paper for heat-sensitive stencil printing according to claim 1, wherein the thermoplastic resin fibers of the support layer (A) are mainly polyester resin fibers. 5. The melting point (Tm1) of the thermoplastic resin film.
And the melting point (Tm2) of the thermoplastic resin fiber is Tm1 ≦ Tm
2. The heat-sensitive stencil printing base paper according to claim 1, which is 2. 6. A thermoplastic resin film having a thickness of 0.1 to 10.
It is 10 micrometers, The base paper for heat-sensitive stencil printing in any one of Claims 1-5 characterized by the above-mentioned. 7. The heat-sensitive stencil printing base paper according to claim 1, wherein the thermoplastic resin film is mainly a polyester resin film.