JPH07237368A - Heat-sensitive stencil printing paper - Google Patents

Abstract

PURPOSE:To obtain paper which improves perforating sensitivity of a film, can satisfy further heat-resistant stability of a substrate and is superior in printability. CONSTITUTION:Heat sensitive stencil printing paper is composed by a method wherein a porous substrate comprising a thermoplastic resin fiber is laminated to a thermoplastic resin film and when crystal melting energy and a thickness of the thermoplastic resin film are set respectively to DELTAHul (cal/g) and t (mum) and crystal melting energy and a mean fiber diameter are set respectively to DELTAHu2 (cal/g) and d (mum), DELTAHu1Xt<DELTAHu2Xd is given.

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 which is perforated by a halogen lamp, a xenon lamp, a flash bulb or the like for flash or infrared irradiation, pulsed irradiation of a laser beam, or a thermal head. is there.

[0002]

2. Description of the Related Art As a base paper for heat-sensitive stencil printing conventionally used for heat-sensitive stencil printing, thermoplastic resin films such as acrylonitrile film, polyester film, vinylidene chloride film, and thin paper made of natural fiber or synthetic fiber, There is known a structure in which a non-woven fabric, a porous support made of a screen gauze or the like is bonded with an adhesive (for example, JP-A-51-2512,
JP-A-51-2513, JP-A-57-18249
5, JP-A-58-147396, JP-A-5-
9-1159898, etc.).

However, these conventional heat-sensitive stencil printing base papers are not always satisfactory in terms of the sharpness of the printed image.

The heat-sensitive stencil printing referred to in the present invention means that a master is prepared by melting and punching the film of the heat-sensitive stencil printing base paper with the above-mentioned thermal head or the like corresponding to the characters and figures of the printed original. Supply printing ink from the support side and let it permeate through the perforated part of the film,
Printing is performed on a printing paper in contact with the film surface of the master.

There are various possible reasons why the image clarity of a printed matter using a conventional heat-sensitive stencil printing paper is not sufficient, one of which is due to the fibers constituting the support. For example, thin paper made of natural fibers, which has been used most often in the past, has thick and uneven fibers, resulting in uneven ink permeability, faint printing, and film perforation. There were drawbacks such as white spots in solid printing due to the fibers present in the part.

In order to improve these drawbacks, a heat-sensitive stencil sheet made of a paper or non-woven fabric mainly made of synthetic fibers such as polyester fibers and polypropylene fibers is used for the purpose of making the thickness of the fibers of the support thin or uniform. A base paper for printing has been proposed (JP-A-59-2896, JP-A-59-1).
6793, JP-A-2-67197, etc.).

However, papermaking papers and non-woven fabrics mainly composed of these synthetic fibers have improved image sharpness as compared with thin papers made of natural fibers, but are heated by the thermal head when the film of the base paper is perforated. However, the fibers of the support are thermally deformed to cause wrinkles on the base paper, and the printed image is distorted.

[0008] Another cause that the printed image of the conventional heat-sensitive stencil printing paper is not sufficiently sharp is due to the perforation sensitivity of the film constituting the paper. That is, if the perforation sensitivity of the film is low, the perforations corresponding to the characters and figures of the printed document become incomplete, and unpunched portions may occur in some cases. When the perforation of the film is incomplete, the ink transmission is naturally incomplete, and as a result, the characters and figures of the printed matter are missing.

[0009]

DISCLOSURE OF THE INVENTION The present invention solves the above problems, has a good perforation sensitivity, and is a heat-sensitive stencil excellent in image clarity in which the support is not thermally deformed by the temperature during perforation. It is intended to provide a printing base paper.

[0010]

In order to achieve the above object, the inventors of the present invention have earnestly studied the perforation mechanism of heat-sensitive stencil printing base paper (hereinafter referred to as "base paper"), and as a result, the thermal characteristics of the film and the support have been improved. The present invention has been completed by finding that the drawbacks of the conventional base paper can be improved by the specification. That is, the present invention is a heat-sensitive stencil printing base paper comprising a thermoplastic resin film and a porous support made of a thermoplastic resin fiber laminated on the thermoplastic resin film, wherein the crystal melting energy of the thermoplastic resin film is ΔHu1 (cal /
g), the thickness is t (μm), the crystal melting energy of the thermoplastic resin fiber is ΔHu 2 (cal / g), and the average fiber diameter is d (μm), ΔHu 1 × t <ΔHu 2 × d
The present invention relates to a heat-sensitive stencil printing base paper.

The thermoplastic resin film in the present invention is
For example, conventionally known materials such as polyester, polyamide, polypropylene, polyethylene, polyvinyl chloride, polyvinylidene chloride or copolymers thereof are used, and polyester film is particularly preferably used from the viewpoint of perforation sensitivity.

The polyester used in 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
Usually, it is preferably stretched, and can be produced by a conventionally known T-die method, inflation method, or the like. For example, in the T-die method, a polymer is extruded onto a cast drum to produce an unstretched film, which is then longitudinally stretched by a heating roll group and, if necessary, is supplied to a tenter or the like to be transversely stretched. You can The thickness of the unstretched film can be adjusted by adjusting the slit width of the die, the discharge amount of the polymer, the number of rotations of the cast drum, and the rotation speed of the heating roll group and the tenter can be adjusted. By changing the set width, it is possible to stretch at a desired stretch ratio.

When producing a polyester film, the intrinsic viscosity of the polymer is usually preferably 0.6 or more, more preferably 0.65 or more. When the intrinsic viscosity is 0.6 or more, the film-forming stability is high, and in particular, thin products can be easily cast.

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, a wax or a polysulfate. An antifoaming agent such as siloxane 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 thickness (t) of the thermoplastic resin film in the present invention is usually preferably 0.1 to 10 μm,
More preferably 0.1 to 5 μm, particularly preferably 0.1.
Is about 3 μm. If the thickness is 10 μm or less, the perforation property is good, and if it is 0.1 μm or more, the film-forming stability is good.

The thermoplastic resin film in the present invention is
Crystal melting energy (ΔHu1) is preferably 3 to 11
cal / g, more preferably 5-10 cal / g. When ΔHu1 is 3 cal / g or more, the perforated shape of the film is stable and a good printed image can be obtained. When .DELTA.Hu1 is 11 cal / g or less, the perforation sensitivity is good.

The thermoplastic resin film in the present invention is
Usually, the product (ΔHu1 × t) of the crystal melting energy (ΔHu1) and the film thickness (t) is preferably 25 cal.
μm / g or less, more preferably 20 cal · μm
/ G or less, particularly preferably 15 cal · μm / g or less. When ΔHu1 × t is 25 cal · μm / g or less, the perforation sensitivity is good, a missing portion does not occur in the printed image, and the expression of shade in solid printing is excellent.

As the thermoplastic resin fibers in the present invention, conventionally known ones such as polyester, polyamide, polyphenylene sulfide, polyacrylonitrile, polypropylene, polyethylene or copolymers thereof can be used. From the viewpoint, polyester is particularly preferably used. Preferable examples of the polyester include polyethylene terephthalate, polyethylene naphthalate, polycyclohexane dimethylene terephthalate, and a copolymer of ethylene terephthalate and ethylene terephthalate. From the viewpoint of thermal dimensional stability during perforation, polyethylene terephthalate and polyethylene naphthalate are particularly preferable. These polymers may include flame retardants, heat stabilizers, antioxidants, ultraviolet absorbers, antistatic agents, pigments, if necessary.
Organic lubricants such as dyes, fatty acid esters and waxes, defoaming agents such as polysiloxanes and the like can be added.

The form of the porous support made of thermoplastic resin fibers in the present invention is not particularly limited,
Any material can be used as long as it has strength as a support, ink retention and permeability. For example, it may be a papermaking paper made from short fibers, a non-woven fabric or a woven fabric, or a screen gauze or the like. Above all, a non-woven fabric is more preferably used in terms of ink permeability and holding property.

The non-woven fabric can be produced by a conventionally known direct melt spinning method such as a flash spinning method, a melt blow spinning method, and a spun bond spinning method. When the polymer used is polyester, its intrinsic viscosity is usually preferably 0.
It is 4 or more, more preferably 0.5 or more, and particularly preferably 0.6 or more. For example, in the melt blow spinning method,
When the molten polymer is discharged from the die, hot air is blown from the periphery of the die, the polymer discharged by the hot air is made finer, and then the polymer is blown and collected on a net conveyor arranged at an appropriate position to collect the web. Formed and manufactured. By adjusting the polymer discharge amount, the hot air temperature, the hot air flow rate, the conveyor moving speed, etc., the basis weight of the web and the single yarn fineness can be arbitrarily set.

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 on a conveyor to form a web. By appropriately setting the polymer discharge amount and the conveyor speed, it is possible to arbitrarily set the fineness and the weight of the web.

In the porous support of the present invention, the surface of the fiber constituting the ink is optionally subjected to chemical treatment with acid, alkali or the like, corona treatment, low temperature plasma treatment or the like in order to impart affinity with the ink. Good.

The diameter (d) of the thermoplastic resin fibers constituting the porous support of the present invention is usually preferably 0.5 to 60.
μm, more preferably 0.5 to 30 μm, and particularly preferably 1 to 20 μm. When the diameter is 0.5 μm or more, the strength as a support is sufficient, and when the diameter is 60 μm or less, the thickness and the basis weight of the support are uniform, and the ink transmission is uniform.

The fiber diameter referred to in the present invention is an equivalent circular diameter, and the fiber cross section is not necessarily circular, and may be elliptical, flat, or polygonal. Fibers having different cross-sectional shapes may be mixed. Further, all the fibers may have the same diameter, or fibers having different diameters may be mixed. When fibers of different diameters are mixed, the fiber diameter refers to their average diameter. Further, in the present invention, a multi-layer structure in which fibers having different diameters are laminated stepwise may be used. In the case of a multi-layer structure, it is more preferable in terms of a balance between image clarity and support strength that at least the layer facing the film is composed of fibers having a small diameter and the remaining layers are composed of fibers having a large diameter.

The crystal melting energy (ΔHu2) of the thermoplastic resin fiber constituting the porous support of the present invention is usually 5c.
Al / g or more is preferable, more preferably 7 cal / g
The above is particularly preferable, and it is 9 cal / g or more. When the crystal melting energy is 5 cal / g or more, the heat resistance of the support is good.

In the porous support of the present invention, the product (ΔHu2 × d) of the crystal melting energy (ΔHu2) of the thermoplastic resin fiber and the average fiber diameter (d) is usually preferably 5 ca.
l · μm / g or more, more preferably 10 cal · μm /
g or more.

The thermoplastic resin fibers forming the porous support of the present invention are preferably stretched and oriented. Generally, the birefringence (Δn) is preferably 0.1 or more, more preferably 0.12 or more, and particularly preferably 0.14 or more. When the birefringence is 0.1 or more, the fiber strength is high and sufficient support strength can be obtained.

The crystallinity of the fibers constituting the porous support of the present invention is usually preferably 20% or more, more preferably 30% or more, particularly preferably 35% or more.
When the crystallinity is 20%, sufficient heat resistance as a support can be obtained.

The fiber basis weight of the porous support in the present invention is usually preferably 1 to 20 g / m ² , more preferably 1 to 16 g / m ² , and particularly preferably 1 to 14 g / m ² .
m ² . When the basis weight is 20 g / m ² or less, the ink permeability is good and the image clarity is excellent. When the basis weight is 1 g / m ² or more, sufficient strength as a support can be obtained.

The porous support in the present invention is preferably formed by forming a mesh-like body having fusion points where fibers are fused to each other at their entanglement points or contact points. Particularly preferably, a thin film extending between two or more fibers is formed at a part of the fusion points in the mesh. That is, since the fibers of the support form a mesh-like body having a fusion point formed by forming a thin film, the strength of the support is stabilized and a uniform open pore shape can be formed. In addition, it is possible to obtain a base paper which is excellent in transportability and has a good balance between retention of printing ink and permeability.

In the present invention, the fusion-bonding thin film means a so-called "duck's foot watering" shape, "frog's foot watering" shape, or "fold" shape, and usually two or more. It is formed straddling between fibers, and the thickness thereof is smaller than the average diameter of the fibers. The size of the thin film is not particularly limited, but is usually 1 μm ² or more, preferably 5 μm ² or more in area.

In the present invention, it is not necessary to form such a "duck's foot watering" -like or "frog foot watering" -like or "fold" -like thin film at all fusion points, and the support is On the average surface, the number of fusion points formed by forming the above-mentioned thin film is usually preferably 1 or more, more preferably 10 or more, and particularly preferably 50 or more per 1 mm ² . When the number of fusion points formed by forming a thin film is 1 or more per 1 mm ² , the strength of the support becomes stable, the shape of the openings in the support becomes uniform, and the ink holding property becomes good. Show-through is less likely to occur.

The area fraction of the openings formed by the reticulate body, which is obtained by directly observing the surface of the porous support of the present invention by a bright field transmission method using an optical microscope, is usually preferably 5 to 80%, and more preferably. 5 to 50%, particularly preferably 5 to 30%.
If the open area fraction is 5% or more, the ink permeability is high, and if it is 80% or less, the ink holding property is good.
Further, when the apertures formed by the reticulate body observed by the bright field transmission method of an optical microscope are regarded as circles, the average equivalent circular diameter is preferably 5 to 100 μm, more preferably 5
-60 μm, particularly preferably 5-30 μm. If the average diameter is 5 μm or more, the ink permeability is good and 10
If it is 0 μm or less, the ink holding property is good.

In the base paper of the present invention, the product of the crystal melting energy (ΔHu1) and the thickness (t) of the thermoplastic resin film is (ΔHu1 × t), and the crystal melting energy (ΔHu2) of the thermoplastic resin fiber is set. When the product of the average fiber diameter (d) and (ΔHu2 × d) is given, it is usually preferable that ΔHu
1 × t <ΔHu2 × d. More preferably, ΔHu
The difference between 1 × t and ΔHu2 × d is 2 cal · μm / g or more, particularly preferably 4 cal · μm / g or more. That is, by making the heat capacity of the porous support larger than that of the thermoplastic resin film, the fibers of the support can be kept in a thermally stable state even when the film is melt-punched by a thermal head or the like. Therefore, the fibers do not melt or deform. That is, since the fibers of the porous support can reliably hold the perforated shape of the film, the printed matter using the base paper does not have characters or images crushed or distorted, and clear characters or images can be obtained. You can get it.

The melting point (Tm1) of the thermoplastic resin film constituting the base paper of the present invention and the melting point (Tm2) of the thermoplastic resin fibers forming the porous support are preferably Tm1≤
Tm2, more preferably the temperature difference is 5 ° C or more,
It is particularly preferably 20 ° C. or higher. When Tm1≤Tm2, the perforability of the film is good and the heat resistance of the support is sufficient.

The peel strength between the thermoplastic resin film constituting the base paper of the present invention and the porous support is preferably 1 g / 2.
It is 5 mm or more, more preferably 5 g / 25 mm or more, and particularly preferably 10 g / 25 mm or more. Peel strength is 1
When it is g / 25 mm or more, wrinkles do not occur when the base paper is supplied and conveyed to the printing machine.

The base paper in the present invention is made by laminating and integrating the above-mentioned thermoplastic resin film and a porous support made of thermoplastic resin fibers. The lamination may be performed by using an adhesive under conditions that do not reduce the perforation sensitivity of the film, or the film and the support fiber may be directly fixed to each other without using the adhesive.

For direct fixing, it is usually preferable to carry out thermocompression bonding in which the thermoplastic resin film and the support fiber are directly bonded while heating. The method of thermocompression bonding is not particularly limited, but thermocompression bonding with a heating roll or a double belt press is particularly preferable from the viewpoint of processability. The thermocompression bonding temperature is usually preferably between the glass transition temperature (Tg) and the melting point (Tm) of the thermoplastic resin film,
It is more preferably between Tg and the cold crystallization temperature (Tcc), and particularly preferably in the range of Tg + 10 ° C to Tg + 50 ° C.

As a preferred embodiment of the present invention, it is particularly preferable that a non-stretched thermoplastic resin film is laminated with a porous support made of the same non-stretched thermoplastic resin fiber, thermocompression bonded and co-stretched. . By co-stretching in the state of thermocompression bonding, the film and the support can be suitably stretched without being separated, and by co-stretching the two together, the thermoplastic resin fiber is reinforced. Therefore, even if the thickness of the film is thin, the film is not torn, the film-forming stability is extremely excellent, and as a result, the base paper with low manufacturing cost can be obtained. At this time, the fibers of the support are fused to each other at the entanglement points and the contact points to form a mesh body having the fusion points. Further, at some of these fusion points, a thin film extending between two or more fibers is formed.

The method of co-stretching is not particularly limited, and either uniaxial stretching or biaxial stretching may be used. Biaxial stretching is more preferable in terms of the orientation of the film and the uniform dispersibility of the support fibers. 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 stretching temperature depends on the glass transition temperature (Tg) and the cold crystallization temperature (Tc) of the thermoplastic resin film.
It is preferably between c). The stretching ratio is not particularly limited and may be appropriately determined depending on the type of thermoplastic polymer used, the sensitivity required for the base paper, and the like, but is usually preferably 2 to 8 times in each of the length and width, more preferably 3 to 8 times is appropriate. Further, after biaxial stretching, it may be re-stretched longitudinally or laterally or longitudinally and laterally.

Further, the base paper of the present invention after biaxial stretching may be heat treated. By heat treatment, the perforation sensitivity of the film can be improved, and heat resistance can be imparted to the support. The heat treatment conditions are not particularly limited and are appropriately determined depending on the type of the thermoplastic polymer used. In the case of polyester resin, the heat treatment temperature is usually 100 to 240 ° C., and the time is preferably 0.5 to 60 seconds. Is.

The base paper obtained by the heat treatment is once cooled to about room temperature and then at a relatively low temperature of 40 to 90 ° C. for 5 minutes.
It can be aged for about a week to a minute. When such aging is adopted, curling and wrinkles do not occur during storage of the base paper or in the printing machine, which is particularly preferable.

A release agent is preferably applied to the film surface of the base paper of the present invention to prevent sticking during perforation. As the release agent, conventionally known release agents such as silicone oil, silicone-based resin, fluorine-based resin, and surfactant can be used, but the following release agents are particularly preferable.

That is, a releasing agent containing a mixture of a petroleum wax (A), a vegetable wax (B) and an oily substance (C) which is soluble, emulsified or suspended in water as a main component is particularly preferable. Here, the main component means that the weight ratio of the mixture of (A), (B) and (C) is 50% or more, preferably 60% or more.

Examples of petroleum waxes include paraffin wax, microcrystalline wax, and oxidized wax. Of these, the use of oxidized wax is particularly preferable.

Examples of the vegetable waxes include candela wax, carnaupa wax, wood wax, oliqury wax, sugar cane wax and the like. In the present invention, a composition comprising the following compounds is particularly preferable.

That is, {rosin or disproportionated rosin,
Or hydrogenated rosin / α / β-substituted ethylene (α-substituent: carboxyl, β-substituent: hydrogen, methyl or carboxyl) additive} / alkyl or alkenyl (each having 1 carbon atom)
~ 8) It is particularly preferred to use ester additives of poly (repeating units: 1-6) alcohol.

The mixing ratio of the petroleum wax and the vegetable wax is 10/90 to 90/10% by weight, preferably 20.
/ 80 to 80/20% by weight, more preferably 30/7
It is preferably from 0 to 70/30% by weight. The reason why the vegetable wax is 10% by weight or more is that it has good uniform dispersibility when emulsified or suspended in water and is suitable for obtaining a uniform coating film. Further, when the amount of the petroleum wax is 10% by weight or more, the coating film has good slipperiness and good running property at high speed perforation.

Further, in the present invention, a mixture obtained by further adding an oily substance to the above petroleum wax (A) and vegetable wax (B) is used. Here, the oily substance is a liquid or paste at room temperature. Oil, vegetable oil,
Examples thereof include fats and oils, mineral oils, synthetic lubricating oils and the like. As vegetable oil, linseed oil, kaya oil, saffron oil, soybean oil,
Examples include cinnamon oil, sesame oil, corn oil, rapeseed oil, bran oil, cottonseed oil, olive oil, southern oil, camellia oil, castor oil, peanut oil, balm oil, and coconut oil. Fats and oils include beef tallow, pork oil, sheep oil, cacao oil and the like, and mineral oils include machine oil, insulating oil, turbine oil, motor oil, gear oil, cutting oil, liquid paraffin and the like.
As the synthetic lubricating oil, those satisfying the requirements described in Encyclopedia of Chemistry (Kyoritsu Publishing Co., Ltd.) can be arbitrarily used, and examples thereof include olefin polymerized oil, diester oil, polyalkylene glycol oil, and silicone oil. it can. Among these, mineral oil and synthetic lubricating oil are preferable. Also,
A mixed system of these may be used.

It is necessary to add 1 to 100 parts by weight, preferably 3 to 50 parts by weight of the oily substance (C) to 100 parts by weight of the mixture of the petroleum wax (A) and the vegetable wax (B). . When the amount of the oily substance is 1 part by weight or more, the running property in the high applied energy region is good.
Further, when the amount is 100 parts by weight or less, the running property in the low applied energy region is good.

When a mixture of vegetable wax, petroleum wax or oily substance is used, a uniform coating film can be easily obtained, as compared with the case where any one of them is used alone.
Good running performance and less sticking.

Various additives can be used in combination in the above composition within a range that does not impair the effects of the present invention. Examples thereof include antistatic agents, heat-resistant agents, antioxidants, organic particles, inorganic particles and pigments.

Further, various additives such as dispersion aids, surfactants, preservatives and antifoaming agents may be added to the coating composition for the purpose of improving dispersibility in water.

The thickness of the release agent layer is 0.005 μm or more and 0.1.
It is 4 μm or less, preferably 0.01 μm or more and 0.4 μm or less. When the thickness of the release agent layer is 0.4 μm or less, the running property at the time of punching is good and the contamination of the head is small.

When the release agent layer is applied in the present invention, the coating liquid is preferably a coating liquid dissolved, emulsified or suspended in water from the viewpoint of explosion proof property and environmental pollution.

The release agent may be applied at any stage before or after the film is stretched, or at any stage after the longitudinal stretching and before the lateral stretching. However, the application before the lateral stretching is particularly preferable in view of the process. The coating method is not particularly limited, but it is preferable to use a roll coater, a gravure coater, a reverse coater, a bar coater or the like.

If necessary, the coating surface may be subjected to corona discharge treatment in air or other various atmospheres before coating with the release agent.

[0059]

[Characteristics measurement method]

(1) Melting point (Tm, ° C) Differential scanning calorimeter RDC220 manufactured by Seiko Instruments Inc.
Using the mold, collect 5 mg of sample and raise the temperature from room temperature to 20
It was determined from the peak temperature of the endothermic curve when the temperature was raised at ° C / min.

(2) Crystal melting energy (ΔHu) Differential scanning calorimeter RDC220 manufactured by Seiko Denshi Kogyo Co., Ltd.
Using the mold, it is determined from the area of the film or fiber when it is melted. This area is the area from the baseline to the absorption side by increasing the temperature, and the area until returning to the position of the baseline when the temperature is further increased. Find (a).
In (indium) is measured under the same DSC conditions, and the area (b) is set to 6.8 cal / g, and is calculated by the following equation.

ΔHu = 6.8 × a / b (cal / g) {circle around (3)} Fiber diameter (μm) Magnification 2000 at arbitrary 10 points of sample with electron microscope
Take 10 times the number of photographs, measure the diameter of any 15 fibers per photograph, do this for 10 photographs, measure the diameter of 150 fibers in total, and use the average value. expressed.

(4) Fiber areal weight (g / m ² ) A 20 cm × 20 cm test piece was taken, and its weight was measured and converted into weight per m ² .

(5) Intrinsic viscosity [η] The sample was dried at 105 ° C for 20 minutes and then dissolved in o-chlorophenol by stirring at 160 ° C for 15 minutes. After cooling, the viscosity at 25 ° C. was measured with a Yamatrabotic AVM-10S type automatic viscosity meter.

(6) Crystallinity (%) The sample was placed in a density gradient tube composed of a mixed solution of n-heptane and carbon tetrachloride, and the value was read after 10 hours or more to determine the density. The density of crystallinity 0% is 1.335 g / c
m ³ , density of 100% crystallinity 1.455 g / cm ³
As, the crystallinity of the sample was calculated.

(7) Birefringence (Δn) Retardation was calculated by a Berek compensator method using a sodium lamp as a light source and immersing the sample in α-promnaphthalene under a polarizing microscope.

(8) Formation of a thin film of fiber fusion points A sample was made by Topcon Scanning Electron Microscope DS130
Was observed at a magnification of 100 to 300 times.

(9) Area Fraction (%) of Openings of Support Material The support surface of the base paper was directly observed by the bright-field transmission method of an optical microscope, and an image analysis device for Hi-Vision made by Pierce Co., Ltd. was used. Then, the area ratio of the aperture was determined at a monitor magnification of 240 times. The open area fraction was calculated at 10 arbitrary measurement points, and the average value was calculated.

(10) Average value (μm) of equivalent circular diameters of the apertures of the support. The support surface of the base paper was directly observed by the bright-field transmission method of an optical microscope, and a Hi-vision compatible image analyzer manufactured by Pierce Co., Ltd. Was used to perform black-and-white reversal processing at a monitor magnification of 240 times to obtain the equivalent circular diameter of the opening portion, and the arithmetic mean was calculated. The average value of 10 measurement points was calculated.

(11) Peel strength (g / 25 mm) The peel strength was measured by the 180-degree peel test method according to JIS-K-6854.

(12) Evaluation of perforation sensitivity of film and thermal stability of support Using a Toshiba word processor "Lupo" (JW05V), a print density (perforation energy) was obtained by a thermal head type plate making system.
Was changed to 6 grades, and a mark with a diameter of 2.5 mm was punched on the base paper, and the punched portion was observed with a phase contrast microscope at a magnification of 200 times, and evaluated as follows.

Film perforation sensitivity In the perforated portion of the film, 90% or more corresponding to the number of dots of the thermal head was perforated ⊚, and 80% or more and less than 90% of the number of dots perforated was ◯, dot The number 70% or more and less than 80% of the number of holes was perforated, and the less than 70% of the number of dots was perforated.

Thermal Stability of Support In the above-mentioned perforated portion of the film, the support fibers which were stable without being thermally deformed were ⊚, and those in which some of the fibers were thermally deformed but the perforated shape was retained. ◯: A fiber having a large thermal deformation and a distorted perforation shape was evaluated as Δ, and a part of the fiber melted and the perforation shape collapsed was evaluated as x.

(13) Evaluation of printability Using a Toshiba word processor "Lupo" (JW05V), the printing density (perforation energy) was changed to 6 levels by the thermal head type plate making method, and the JIS first level characters were used. Characters having a size of 2 mm square, 5 mm square, ● (circle filled in black) having a diameter of 2 to 10 mm, and ruled lines having different thicknesses were prepared as originals. What was printed using a plate-making original was evaluated by visual judgment as follows.

Clarity of characters ◎ for clear characters, ○ for slightly unclear characters,
Characters that were unclear but legible were marked as Δ, and characters that were unclear and barely legible were marked as x.

Unevenness of Ruled Line Thickness ⊚ when the ruled line thickness is uniform, ○ when the ruled line thickness is slightly uneven, and Δ when the ruled line thickness is clearly uneven.
Marks with scratches or cuts on the ruled lines were marked as x.

Density of solid black portion The density (OD value) of the solid black portion was measured with a Macbeth densitometer,
OD value is 1.2 or more ⊚, OD value is 1 or more and less than 1.2, ◯, OD value is 0.8 or more and less than 1, Δ,
Those with an OD value of less than 0.8 were marked with x.

[0077]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited thereto.

Example 1 Using a rectangular die having a hole diameter of 0.25 mm and 1000 holes, a polyethylene naphthalate raw material ([η] = 0.63, Tm = 272 ° C.) was spun at a die temperature of 300 ° C. It was dispersed and collected on a conveyor by an ejector at a spinning speed of 2000 m / min to prepare an unstretched nonwoven fabric having a fiber basis weight of 100 g / m ² . The non-woven fabric has a crystallinity of 8% and a birefringence (Δ
n) was 0.006.

Then, polyethylene terephthalate 86
Copolyester resin raw material ([η] = 0.7, Tm
= 228 ° C.) using an extruder with a screw diameter of 40 mm,
The T-die base was extruded at a temperature of 280 ° C. and cast on a cooling drum having a diameter of 300 mm to prepare an unstretched film.

On the unstretched film, the above unstretched nonwoven fabric was superposed, supplied to a heating roll and thermocompression bonded at a roll temperature of 90 ° C. to prepare a laminated sheet.

The laminated sheet was placed between heating rolls at 95 ° C.,
After being stretched 4 times in the length direction, it was fed into a tenter type stretching machine, stretched 5 times in the width direction at 95 ° C., and further heat-treated at 160 ° C. for 5 seconds inside the tenter to prepare a heat-sensitive stencil sheet. A wax-based release agent was applied to the film surface of the base paper at the entrance of the tenter with a gravure coater at a weight of 0.1 g / m ² after drying.

The fiber basis weight of the obtained base paper was 6 g / m ² ,
Average fiber diameter is 5μm, crystal melting energy is 11.5c
The al / g and the birefringence (Δn) were 0.17. Also,
The film thickness is 2 μm, and the crystal melting energy is 7.7.
It was cal / g.

When the base paper was observed with an optical microscope, it was found that the fibers of the support were fused to each other to form a net-like body, and a thin film was formed at a portion of the fusion point across the fibers.

Example 2 A heat-sensitive stencil sheet was prepared under the same conditions as in Example 1 except that the spinning speed was changed, the longitudinal draw ratio was 3 times, and the transverse draw ratio was 4 times.

The basis weight of the base paper was 10 g / m ² , the average fiber diameter was 4 μm, and the crystal melting energy was 11.5 cal.
/ G, the birefringence (Δn) was 0.16. The film thickness is 3 μm and the crystal melting energy is 7.7 ca.
It was 1 / g.

When the base paper was observed with an optical microscope, it was found that the fibers of the support were fused to each other to form a net-like body, and a thin film was formed at a portion of the fusion point across the fibers.

Example 3 Using a rectangular die having a hole diameter of 0.25 mm and 1000 holes, a polyethylene terephthalate raw material ([η] = 0.65, Tm = 257 ° C.) was spun at a die temperature of 290 ° C., and an air ejector was used. At the spinning speed of 2000 m / min, the unstretched nonwoven fabric having a fiber basis weight of 100 g / m ² was dispersed and collected on a conveyer. The nonwoven fabric had a crystallinity of 8% and a birefringence (Δn) of 0.009.

Then, polyethylene terephthalate 82
Copolyester resin raw material consisting of 18 mol% of polyethylene isophthalate ([η] = 0.68, T
m = 212 ° C) is extruded at a T-die die temperature of 280 ° C using an extruder with a screw diameter of 40 mm, and the diameter is 300 mm.
An unstretched film was produced by casting on a cooling drum of

On the unstretched film, the above-mentioned unstretched nonwoven fabric was laid, supplied to a heating roll and thermocompression bonded at a roll temperature of 90 ° C. to prepare a laminated sheet.

The laminated sheet was stretched 4 times in the length direction with a heating roll at 95 ° C. and then fed into a tenter type stretching machine,
It was stretched 5 times in the width direction at 95 ° C. Further, it was heat-treated at 160 ° C. for 5 seconds inside the tenter to prepare a heat-sensitive stencil sheet. In addition, at the inlet of the tenter, a wax-based release agent was applied to the film surface by a gravure coater with a dry weight of 0.1 g / m ² .

The fiber basis weight of the obtained base paper was 8 g / m ² ,
Average fiber diameter is 5 μm, crystal melting energy is 9 cal /
g, and birefringence (Δn) was 0.165. The film thickness is 2 μm and the crystal melting energy is 6.8 ca.
It was 1 / g.

When the base paper was observed with an optical microscope, it was found that the fibers of the support body were fused to each other to form a net-like body, and a thin film was formed at a portion of the fusion point across the fibers.

Example 4 A heat-sensitive stencil sheet was prepared under the same conditions as in Example 3 except that the spinning speed was changed, the longitudinal draw ratio was 3 times, and the transverse draw ratio was 4 times.

The basis weight of the base paper was 12 g / m ² , the average fiber diameter was 4 μm, the crystal fusion energy was 9 cal / g,
The birefringence (Δn) was 0.155. The film thickness is 3 μm, and the crystal melting energy is 6.8 cal /
It was g.

When the base paper was observed with an optical microscope, it was found that the fibers of the support were fused to each other to form a mesh-like body, and a thin film was formed at a portion of the fusion point across the fibers.

Example 5 Using a rectangular die having a hole diameter of 0.35 mm and 100 holes,
A polyethylene terephthalate raw material ([η] = 0.6, Tm = 254 ° C.) was spun by a melt-blowing method at a die temperature of 280 ° C., fibers were dispersed and collected on a conveyor, and a basis weight was 10
An unstretched nonwoven fabric of 0 g / m ² was prepared. The non-woven fabric had a crystallinity of 7% and a birefringence (Δn) of 0.008.

Then, polyethylene terephthalate 82
Copolyester resin raw material consisting of 18 mol% of polyethylene isophthalate ([η] = 0.68, T
m = 212 ° C) is extruded at a T-die die temperature of 280 ° C using an extruder with a screw diameter of 40 mm, and the diameter is 300 mm.
An unstretched film was produced by casting on a cooling drum of

The above unstretched nonwoven fabric was laid on the unstretched film, supplied to a heating roll, and thermocompression bonded at a roll temperature of 80 ° C. to prepare a laminated sheet.

The laminated sheet was placed between heating rolls at 90 ° C.,
After being stretched 4 times in the length direction, it was fed into a tenter type stretching machine, stretched 5 times in the width direction at 95 ° C., and further heat-treated at 160 ° C. for 5 seconds inside the tenter to prepare a heat-sensitive stencil sheet. A wax-based release agent was applied to the film surface of the base paper at the entrance of the tenter with a gravure coater at a weight of 0.1 g / m ² after drying.

The fiber basis weight of the obtained base paper was 6 g / m ² ,
Average fiber diameter is 3μm, crystal melting energy is 11.2c
The al / g and the birefringence (Δn) were 0.145. The film thickness was 3.5 μm, and the crystal fusion energy was 6.8 cal / g.

When the base paper was observed with an optical microscope, it was found that the fibers of the support were fused to each other to form a net-like body, and a thin film was formed at a portion of the fusion point across the fibers.

Example 6 A polyethylene terephthalate raw material ([η] = 0.65, Tm = 257 ° C.) was spun at a die temperature of 290 ° C. using a rectangular die having a hole diameter of 0.25 mm and 1000 holes, and an air ejector was used. At the spinning speed of 2000 m / min, the unstretched nonwoven fabric having a fiber basis weight of 100 g / m ² was dispersed and collected on a conveyer. The nonwoven fabric had a crystallinity of 8% and a birefringence (Δn) of 0.009.

Then, polyethylene terephthalate 75
Copolyester resin raw material ([η] = 0.72, T
m = 195 ° C.) is extruded at a T-die mouthpiece temperature of 280 ° C. using an extruder having a screw diameter of 40 mm, and the diameter is 300 mm.
An unstretched film was produced by casting on a cooling drum of

On the unstretched film, the above-mentioned unstretched nonwoven fabric was laid, supplied to a heating roll and thermocompression bonded at a roll temperature of 90 ° C. to prepare a laminated sheet.

The laminated sheet was stretched 4 times in the length direction with a heating roll at 95 ° C. and then fed into a tenter type stretching machine,
It was stretched 5 times in the width direction at 95 ° C. Further, it was heat-treated at 160 ° C. for 5 seconds inside the tenter to prepare a heat-sensitive stencil sheet. In addition, at the inlet of the tenter, a wax-based release agent was applied to the film surface by a gravure coater with a dry weight of 0.1 g / m ² .

The fiber basis weight of the obtained base paper was 7 g / m ² ,
Average fiber diameter is 5 μm, crystal melting energy is 9 cal /
g, the birefringence (Δn) was 0.15. The film thickness is 2 μm and the crystal melting energy is 5.9 cal.
/ G.

When the base paper was observed with an optical microscope, it was found that the fibers of the support were fused to each other to form a net-like body, and a thin film was formed at a portion of the fusion point across the fibers.

Example 7 A heat-sensitive stencil sheet was prepared under the same conditions as in Example 6 except that the spinning speed was changed, the longitudinal draw ratio was 3 times and the horizontal draw ratio was 4 times.

The basis weight of the base paper was 12 g / m ² , the average fiber diameter was 4 μm, the crystal melting energy was 9 cal / g,
The birefringence (Δn) was 0.14. The film thickness is 3 μm and the crystal melting energy is 5.9 cal / g.
Met.

When the base paper was observed with an optical microscope, it was found that the fibers of the support were fused to each other to form a net-like body, and a thin film was formed at a portion of the fusion point across the fibers.

Example 8 Using a rectangular die having a hole diameter of 0.35 mm and 100 holes,
Polyethylene terephthalate raw material ([η] = 0.6, Tm = 254) at a die temperature of 280 ° C. and a discharge rate of 50 g / min.
° C.) was spun and by a melt blow method, to prepare an unstretched nonwoven fabric having a basis weight of 100 g / m ² dispersed collecting the fibers on a conveyor. The nonwoven fabric had a crystallinity of 5% and a birefringence (Δn) of 0.005.

Then, polyethylene terephthalate 75
Copolyester resin raw material ([η] = 0.72, T
m = 195 ° C.) is extruded at a T-die mouthpiece temperature of 280 ° C. using an extruder having a screw diameter of 40 mm, and the diameter is 300 mm.
An unstretched film was produced by casting on a cooling drum of

On the unstretched film, the above-mentioned unstretched nonwoven fabric was superposed, supplied to a heating roll and thermocompression-bonded at a roll temperature of 80 ° C. to prepare a laminated sheet.

The laminated sheet was placed between heating rolls at 90 ° C.,
After stretching 4 times in the length direction, it was fed into a tenter type stretching machine, stretched 5 times in the width direction at 95 ° C., and further heat-treated in the tenter at 160 ° C. for 5 seconds to prepare a heat-sensitive stencil sheet. A wax-based release agent was applied to the film surface of the base paper at the entrance of the tenter with a gravure coater at a weight of 0.1 g / m ² after drying.

The fiber basis weight of the obtained base paper was 6.5 g / m.
² , the average fiber diameter is 3 μm, and the crystal melting energy is 11.
It was 2 cal / g and the birefringence (Δn) was 0.16. The film thickness was 3.5 μm, and the crystal fusion energy was 5.9 cal / g.

When the base paper was observed with an optical microscope, it was found that the fibers of the support were fused to each other to form a net-like body, and a thin film was formed at a portion of the fusion point across the fibers.

Comparative Example 1 A rectangular die having a hole diameter of 0.35 mm and 100 holes was used.
A polyethylene naphthalate raw material ([η] = 0.5, Tm = 270 ° C.) was spun by a melt-blowing method at a spinneret temperature of 300 ° C., fibers were dispersed and collected on a conveyor, and a basis weight was 10
An unstretched nonwoven fabric of 0 g / m2 was prepared. The non-woven fabric had a crystallinity of 6% and a birefringence (Δn) of 0.005.

Then, polyethylene terephthalate 86
Copolyester resin raw material ([η] = 0.7, Tm
= 228 ° C.) using an extruder with a screw diameter of 40 mm,
The T-die base was extruded at a temperature of 280 ° C. and cast on a cooling drum having a diameter of 300 mm to prepare an unstretched film.

The unstretched nonwoven fabric was placed on the unstretched film, supplied to a heating roll, and thermocompression bonded at a roll temperature of 95 ° C. to prepare a laminated sheet.

The laminated sheet was placed between heating rolls at 95 ° C.,
After stretching 4 times in the length direction, it was fed into a tenter type stretching machine, stretched 5 times in the width direction at 95 ° C., and further heat-treated in the tenter at 160 ° C. for 5 seconds to prepare a heat-sensitive stencil sheet. A wax-based release agent was applied to the film surface of the base paper at the entrance of the tenter with a gravure coater at a weight of 0.1 g / m ² after drying.

The fiber basis weight of the obtained base paper was 6.5 g / m.
² , average fiber diameter is 2.4μm, crystal melting energy is 1
It was 1 cal / g. The film thickness is 3.5.
μm, and the crystal melting energy was 7.7 cal / g.

Comparative Example 2 A heat-sensitive stencil sheet was prepared under the same conditions as in Comparative Example 1, except that the spinning conditions in Comparative Example 1 were changed so that the longitudinal draw ratio was 3 times and the transverse draw ratio was 4.

The basis weight of the base paper was 13 g / m ² , the average fiber diameter was 2 μm, and the crystal melting energy was 11 cal / g.
Met. The film thickness was 4 μm, and the crystal fusion energy was 7.7 cal / g.

Comparative Example 3 A heat sensitive stencil sheet was prepared under the same conditions as in Comparative Example 5, except that the spinning conditions were changed to 3 times in the longitudinal stretching ratio and 4 times in the transverse stretching ratio in Example 5.

The fiber basis weight of the base paper is 12.5 g / m ² ,
Average fiber diameter is 2μm, crystal melting energy is 11.2c
It was al / g. The thickness of the film was 4 μm and the crystal melting energy was 6.8 cal / g.

Comparative Example 4 In Example 8, the spinning conditions were changed, and the longitudinal draw ratio was set to 3 times and the transverse draw ratio was set to 4 times to prepare a heat sensitive stencil sheet.

The fiber basis weight of the base paper is 14.5 g / m ² ,
Average fiber diameter is 2μm, crystal melting energy is 11.2c
It was al / g. The thickness of the film is 4.5μ
m, and the crystal melting energy was 5.9 cal / g.

Example 9 In Example 3, at a spinning speed of 5000 m / min, a fiber areal weight of 15 g
A nonwoven fabric of / m ² was prepared. The average fiber diameter of the non-woven fabric is 2
The crystal fusion energy was 0 μm, the crystal melting energy was 9 cal / g, and the birefringence (Δn) was 0.17.

Similarly, in Example 3, a film having a thickness of 2 μm was produced. The crystal melting energy of the film is 6.8.
It was cal / g.

Next, the non-woven fabric and the film were bonded together using a vinyl acetate resin adhesive. The amount of adhesive applied was 1 g / m ² . Further, a wax-based releasing agent was applied to the film surface after adhesion with a weight after drying of 0.1 g / m ² to obtain a heat-sensitive stencil sheet.

Example 10 In Example 3, with a spinning speed of 1000 m / min, the basis weight 1
A non-woven fabric of 50 g / m ² was prepared. The non-woven fabric had a crystallinity of 6% and a birefringence (Δn) of 0.008.

Then, using the same raw material as used in Example 3, the polymer discharge rate was reduced to prepare an unstretched film. The non-woven fabric was laminated on the unstretched film, and a base paper was prepared under the same conditions as in Example 3 with a longitudinal stretching ratio of 3 times and a lateral stretching ratio of 4 times.

The basis weight of the base paper was 11 g / m ² , the average fiber diameter was 10 μm, and the crystal melting energy was 9 cal /
g, and birefringence (Δn) was 0.13. The film thickness is 2 μm and the crystal melting energy is 6.8 cal.
/ G.

Example 11 Using a rectangular die having a hole diameter of 0.35 mm and 100 holes,
A polyethylene terephthalate raw material ([η] = 0.51, Tm = 252 ° C.) was spun by a melt-blowing method at a die temperature of 280 ° C., fibers were dispersed and collected on a conveyor, and a basis weight was 1
An unstretched nonwoven fabric of 00 g / m ² was prepared. The nonwoven fabric had a crystallinity of 5% and a birefringence (Δn) of 0.005.

Then, polyethylene terephthalate 84
Copolyester resin raw material ([η] = 0.66, T
m = 210 ° C.) is extruded at a T-die mouthpiece temperature of 275 ° C. using an extruder with a screw diameter of 40 mm, and the diameter is 300 mm.
An unstretched film was produced by casting on a cooling drum of

On the unstretched film, the above-mentioned unstretched nonwoven fabric was laid, supplied to a heating roll and thermocompression bonded at a roll temperature of 85 ° C. to prepare a laminated sheet.

The laminated sheet was placed between heating rolls at 87 ° C.
After stretching 3.5 times in the length direction, it was fed into a tenter type stretching machine, stretched 4 times in the width direction at 93 ° C., and further heat-treated inside the tenter at 150 ° C. for 10 seconds to prepare a heat-sensitive stencil sheet. . At the inlet of the tenter, a wax-based release agent was applied to the film surface of the base paper at a weight after drying of 0.05 g / m ² using a gravure coater.

The fiber basis weight of the obtained base paper was 7.2 g / m.
² , the average fiber diameter is 5 μm, and the crystal melting energy is 11.
It was 0 cal / g and the birefringence (Δn) was 0.12. The film thickness was 1.5 μm, and the crystal fusion energy was 7.0 cal / g.

When the base paper was observed with an optical microscope, it was found that the fibers of the support were fused to each other to form a net-like body, and a thin film was formed at a portion of the fusion point across the fibers.

Example 12 In Example 11, the stretching ratio in the length direction was 3.7 times,
The stretching ratio in the width direction was 4.2 times, and the other conditions were in Example 11.
A heat-sensitive stencil sheet was prepared under the same conditions as described above.

The fiber basis weight of the obtained base paper was 6.4 g / m.
² , the average fiber diameter is 4 μm, and the crystal melting energy is 11.
It was 0 cal / g and the birefringence (Δn) was 0.13. The film thickness was 1.0 μm, and the crystal fusion energy was 7.0 cal / g.

When the base paper was observed with an optical microscope, it was found that the fibers of the support were fused to each other to form a net-like body, and a thin film was formed at a part of the fusion point across the fibers.

Example 13 Similarly to Example 11, the stretching ratio in the length direction was set to 4
10 times, the stretching ratio in the width direction was set to 4.5, and the other conditions were the same as in Example 11 to produce a heat-sensitive stencil sheet.

The fiber basis weight of the obtained base paper was 5.6 g / m.
² , the average fiber diameter is 3 μm, and the crystal melting energy is 11.
It was 0 cal / g and the birefringence (Δn) was 0.14. The film thickness was 0.5 μm, and the crystal fusion energy was 7.0 cal / g.

When the base paper was observed with an optical microscope, it was found that the fibers of the support were fused to each other to form a net-like body, and a thin film was formed at a portion of the fusion point across the fibers.

Example 14 Using a rectangular die having a hole diameter of 0.2 mm and 200 holes, a polyethylene terephthalate raw material ([η] = 0.48, Tm = 253 ° C.) was spun by a melt blow method at a die temperature of 280 ° C. Take out, disperse and collect fibers on the conveyor, and have a basis weight 1.
An unstretched nonwoven fabric of 60 g / m ² was prepared. The nonwoven fabric had a crystallinity of 5% and a birefringence (Δn) of 0.006.

Then, polyethylene terephthalate 80
Copolyester resin raw material ([η] = 0.68, T
m = 205 ° C.) is extruded at a T-die mouthpiece temperature of 275 ° C. using an extruder with a screw diameter of 40 mm, and the diameter is 300 mm.
An unstretched film was produced by casting on a cooling drum of

The unstretched nonwoven fabric was placed on the unstretched film, supplied to a heating roll and thermocompression bonded at a roll temperature of 80 ° C. to prepare a laminated sheet.

The laminated sheet was placed between heating rolls at 85 ° C.,
After stretching 3.5 times in the length direction, it was fed into a tenter type stretching machine, stretched 4 times in the width direction at 90 ° C., and further heat-treated at 170 ° C. for 10 seconds inside the tenter to prepare a heat-sensitive stencil sheet. . A wax-based release agent was applied to the film surface of the base paper at the entrance of the tenter with a gravure coater in a weight after drying of 0.08 g / m ² .

The fiber basis weight of the obtained base paper was 11.4 g /
m ² , average fiber diameter is 2 μm, crystal melting energy is 1
It was 0.8 cal / g and the birefringence (Δn) was 0.13. The film thickness was 1.5 μm, and the crystal fusion energy was 6.4 cal / g.

When the base paper was observed with an optical microscope, it was found that the fibers of the support were fused to each other to form a net-like body, and a thin film was formed at a portion of the fusion point across the fibers.

Example 15 In Example 14, the stretching ratio in the length direction was 3.7 times,
The stretching ratio in the width direction was 4.2 times, and the other conditions were in Example 14.
A heat-sensitive stencil sheet was prepared under the same conditions as described above.

The fiber basis weight of the obtained base paper was 10.3 g /
m ² , average fiber diameter 1 μm, crystal melting energy 1
It was 0.8 cal / g and the birefringence (Δn) was 0.14. The film thickness was 1.0 μm, and the crystal fusion energy was 6.4 cal / g.

When the base paper was observed with an optical microscope, it was found that the fibers of the support were fused to each other to form a mesh-like body, and a thin film was formed at a part of the fusion point across the fibers.

Example 16 Similarly to Example 14, the stretching ratio in the length direction was set to 4
10 times, the stretching ratio in the width direction was set to 4.5, and the other conditions were the same as in Example 14 to produce a heat-sensitive stencil sheet.

The fiber basis weight of the obtained base paper was 8.9 g / m.
² , average fiber diameter is 0.5μm, crystal melting energy is 1
It was 0.8 cal / g and the birefringence (Δn) was 0.15. The film thickness was 0.5 μm, and the crystal fusion energy was 6.4 cal / g.

When the base paper was observed with an optical microscope, it was found that the fibers of the support were fused to each other to form a net-like body, and a thin film was formed at a portion of the fusion point across the fibers.

Example 17 The nonwoven fabric prepared in Example 14 was biaxially stretched 4 × 4 times with a film stretcher at a preheating temperature of 90 ° C. and a preheating time of 30 seconds, and heat treated in a tunnel oven at 160 ° C. for 10 seconds. Then, a porous support was prepared. The fiber weight of the obtained support was 9.8 g / m ² , and the average fiber diameter was 1.5.
μm, the crystal melting energy was 10.8 cal / g, and the birefringence (Δn) was 0.15. When the support was observed with an optical microscope, it was found that the fibers of the support were fused to each other to form a net-like body, and a thin film was formed across the fibers at a part of the fusion point.

Then, under the same conditions as in Example 14, the thickness 1.
A 5 μm biaxially stretched film was produced. The crystal fusion energy of the film was 6.4 cal / g.

Next, the above-mentioned non-woven fabric and film were bonded together using a vinyl acetate resin adhesive. The amount of adhesive applied was 1 g / m ² . Further, a wax-based releasing agent was applied to the film surface after adhesion with a weight after drying of 0.1 g / m ² to obtain a heat-sensitive stencil sheet.

Example 18 As a porous support, a 300-mesh screen gauze made of polyester fiber having a fiber diameter of 45 μm was prepared in both length and weft. The crystal melting energy of the fiber is 12.5 ca.
The l / g and the birefringence (Δn) were 0.17.

Then, under the same conditions as in Example 14, the thickness 1.
A 5 μm biaxially stretched film was produced. The crystal fusion energy of the film was 6.4 cal / g.

Next, the non-woven fabric and the film were attached to each other using a vinyl acetate resin adhesive. The amount of adhesive applied was 1 g / m ² . Further, a wax-based releasing agent was applied to the film surface after adhesion with a weight after drying of 0.1 g / m ² to obtain a heat-sensitive stencil sheet.

[0164]

[Table 1]

[Table 2]

[Table 3]

[Table 4] As can be seen from the results of Table 1, Table 2, Table 3, and Table 4, the product (ΔHu1 × t) of the crystal melting energy ΔHu1 of the thermoplastic resin film and the film thickness t is the heat that constitutes the porous support. Crystal melting energy ΔHu of plastic resin fiber
The heat-sensitive stencil sheet of the present invention, which is smaller than the product of 2 and the fiber diameter d (ΔHu2 × d), has excellent perforation sensitivity of the film and thermal stability of the support, resulting in excellent printing performance. Has become.

[0165]

The base paper for heat-sensitive stencil printing of the present invention comprises the product of the crystal melting energy of the thermoplastic resin film and the film thickness (ΔHu1 × t) and the crystal melting of the thermoplastic resin fiber constituting the porous support. Product of energy and fiber diameter (Δ
(Hu2 xd), ΔHu1 xt <ΔHu2 xd, so that the perforation sensitivity of the film can be improved and the heat resistance stability of the support can be satisfied, resulting in excellent printing performance. The base paper can be obtained.

Claims (15)

[Claims] 1. A base paper for heat-sensitive stencil printing, comprising a thermoplastic resin film and a porous support comprising thermoplastic resin fibers laminated on the thermoplastic resin film, wherein the crystal melting energy of the thermoplastic resin film is ΔHu1 (cal / g). , Thickness t (μm)
And the crystal melting energy of the thermoplastic resin fiber is ΔH
u2 (cal / g), where ΔHu1 xt <ΔHu2 xd, where d (μm) is the average fiber diameter, a heat-sensitive stencil printing base paper. 2. The difference between ΔHu1 × t and ΔHu2 × d is 2c.
2. The heat-sensitive stencil printing base paper according to claim 1, characterized in that it is at least al.μm / g. 3. The porous support forms a reticulated body having fusion points where fibers are fused to each other, and at some of the fusion points in the reticulated body, The heat-sensitive stencil printing base paper according to claim 1 or 2, wherein a thin film extending between the fibers is formed. 4. The base paper for heat-sensitive stencil printing according to claim 1, wherein the thermoplastic resin film and the thermoplastic resin fiber are directly fixed to each other without an adhesive. . 5. The melting point (Tm1) of the thermoplastic resin film.
And the melting point of the thermoplastic resin fiber forming the porous support (T
m2) is Tm1 .ltoreq.Tm2, The heat-sensitive stencil printing base paper according to claim 1, wherein m2) is Tm1.ltoreq.Tm2. 6. The melting point (Tm1) of the thermoplastic resin film.
And the melting point of the thermoplastic resin fiber forming the porous support (T
m2) is Tm1 <Tm2, and the temperature difference is 5
The heat-sensitive stencil printing base paper according to any one of claims 1 to 4, which has a temperature of not less than ° C. 7. A thermoplastic resin film having a thickness of 0.1 to 10.
It is 10 micrometers, The heat sensitive stencil printing base paper in any one of Claims 1-6. 8. The thermoplastic resin film has a thickness of 0.1 to 10.
It is 5 micrometers, The base paper for heat-sensitive stencil printing in any one of Claims 1-6 characterized by the above-mentioned. 9. The base paper for heat-sensitive stencil printing according to claim 1, wherein the thermoplastic resin film has a crystal melting energy of 3 to 11 cal / g. 10. A thermoplastic resin fiber having an average diameter of 0.5.
〜60μm。 1 ~ claim 9 characterized in that
The heat-sensitive stencil printing base paper according to any one of 1. 11. A thermoplastic resin fiber having an average diameter of 1 to 2
It is 0 micrometer, The heat sensitive stencil printing base paper in any one of Claims 1-9 characterized by the above-mentioned. 12. The base paper for heat-sensitive stencil printing according to claim 1, wherein the thermoplastic resin fiber has a crystal melting energy of 5 cal / g. 13. The birefringence (Δn) of the thermoplastic resin fiber is 0.1 or more, and the birefringence (Δn) is 0.1 or more.
2. A base paper for heat-sensitive stencil printing according to any one of 2. 14. The thermoplastic resin film is made of a polyester resin, and the thermoplastic resin film is made of a polyester resin.
The heat-sensitive stencil printing base paper according to any one of 1. 15. The heat-sensitive stencil printing base paper according to claim 1, wherein the thermoplastic resin fiber is made of a polyester resin.