JPH08324149A - Thermal stencil printing base sheet - Google Patents

Abstract

PURPOSE: To obtain a thermal stencil printing base sheet having excellent sensitivity and plate wear resistance by sticking a film formed of specific polymer to nonwoven fabric without intermediary of a bonding agent and specifying the mean fiber size of the fiber for forming the nonwoven fabric. CONSTITUTION: The thermal stencil printing base sheet is perforated to be engraved by flashing light emitting, pulse-like emitting of a laser beam or bringing a thermal head into contact, and formed by sticking the film formed of polymer of ethylene-2, 6-naphthalate of main repetition unit to nonwoven fabric without intermediary of a bonding agent. The mean fiber size of the fiber forming the nonwoven fabric is set to a range of 1 to 15μm. The tensile elastic modulus of the base sheet in its lengthwise direction is preferably 0.20kg/cm or more.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a heat-sensitive stencil printing base paper. More specifically, it relates to a heat-sensitive stencil printing base paper excellent in sensitivity and printing durability, which is punched by flash irradiation, infrared irradiation, pulsed irradiation such as laser beam, or contact with a thermal head.

[0002]

2. Description of the Related Art As a base paper for heat-sensitive stencil printing (hereinafter sometimes referred to simply as "base paper"), a thermoplastic resin film such as a vinylidene chloride film, a polyethylene terephthalate film, a natural fiber, a chemical fiber or a synthetic fiber is used. There is known a structure in which a porous support made of thin paper, non-woven fabric, gauze or the like obtained by mixing these is bonded with an adhesive (for example, Japanese Examined Patent Publication No. 4-6815).
JP-A-51-2513, JP-A-57-1
No. 82495).

However, these conventional base papers have the following drawbacks. That is, (1) since the film and the porous support are bonded together by using an adhesive, the adhesive impedes the transmission of ink, resulting in poor image clarity. (2) Regarding the adhesive itself used, for example, an acrylic resin or vinyl acetate resin adhesive is easily softened, swelled or dissolved by the printing ink, and thus has poor ink resistance and uses a thermosetting adhesive. In this case, since the uncured material is likely to remain, the thermal head is likely to be fused during plate making. (3) Furthermore, when an adhesive is used, an adhesive step is indispensable in the process of manufacturing the base paper, and since a solvent is used when the adhesive is applied, a solvent recovery facility is required, resulting in high cost. (4) In addition, since it is necessary to handle a thin film in the bonding step, problems such as film breakage and wrinkles are likely to occur, resulting in a decrease in yield.

In order to improve these drawbacks, it has been proposed to use as little adhesive as possible (for example, JP-A-58-147396 and JP-A-4).
However, the above-mentioned drawbacks could not be completely eliminated.

Further, as a method using no adhesive, in Japanese Patent Application Laid-Open No. 4-212891, a fiber layer is formed in which a synthetic fiber is sprinkled and thermocompressed on one surface of a thermoplastic resin film. Is proposed. However, since this method is a method in which synthetic fibers having a length of 50 mm or less are scattered by wind force or static electricity, the dispersion of the fibers becomes non-uniform, so that the ink permeability becomes uneven and the printed matter becomes shaded. . Further, in this method, since the adhesiveness between the resin film and the fiber layer is not always sufficient, there is a problem that wrinkles may occur during the transport of the film, or the insufficiently adhered fibers may become foreign matter. In order to improve the adhesiveness, it has been proposed to mix binder fibers into the fiber layer or to apply a small amount of an adhesive to the film surface, but if binder fibers or adhesives are used, the permeability of the ink is impaired, As a result, there is a drawback that the image clarity is reduced.

Further, in JP-A-2-107488, for the purpose of improving image sharpness and printing durability, a heat-sensitive stencil sheet having a thermoplastic film and a non-woven fabric mainly made of synthetic fibers composed of continuous filaments. However, in terms of the balance between ink permeability and printing durability,
It was still insufficient.

Against this background, as a completely new base paper which does not use an adhesive, there has previously been proposed one in which a polyester film and a porous support made of polyester fiber are directly fixed to each other (JP-A-6-305273). Issue). However, it has been found that there is a problem that the base paper is stretched or torn when a large amount is printed because the strength of the base paper is insufficient.

[0008]

SUMMARY OF THE INVENTION It is an object of the present invention to solve various problems of the prior art and to provide a heat sensitive stencil sheet having excellent sensitivity and printing durability.

[0009]

In order to achieve the above object, a heat-sensitive stencil printing base paper according to the present invention comprises a film composed of a polymer whose main repeating unit is ethylene-2,6-naphthalate. A non-woven fabric composed of a polymer whose main repeating unit is ethylene-2,6-naphthalate is adhered without an adhesive, and the fibers constituting the non-woven fabric have an average fiber diameter of 1 to 1.
It is characterized by being 5 μm.

In the present invention, the polymer whose main repeating unit constituting the film is ethylene-2,6-naphthalate means that at least 70 mol% of the repeating units are ethylene-2,6-naphthalate units. It is preferably 80 mol% or more, more preferably 85 mol% or more. When the ethylene-2,6-naphthalate unit is less than 70 mol% of the repeating unit, printing durability is deteriorated, which is not preferable. If it is 30 mol% or less, it may be modified with the following copolymer components. More specifically, a component having a divalent ester-forming functional group such as a dibasic acid or a diol can be used as the copolymerization component,
Aromatic dicarboxylic acids other than 2,6-naphthalenedicarboxylic acid, aliphatic dicarboxylic acids or alicyclic dicarboxylic acids, and diols other than ethylene glycol. More specifically, examples of the aromatic dicarboxylic acid include terephthalic acid, isophthalic acid, phthalic acid, 1,4-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 4,
4'-diphenyldicarboxylic acid, 4,4'-diphenyletherdicarboxylic acid, 4,4'-diphenylsulfonedicarboxylic acid, dicarboxylic acid having a metal sulfonate such as 5-sodium sulfoisophthalic acid, and succinic acid as an aliphatic dicarboxylic acid. , Adipic acid, suberic acid, sebacic acid, dodecanedioic acid, eicosandioic acid, dimer acid and the like can be used. As the alicyclic dicarboxylic acid, 1,4-cyclohexanedicarboxylic acid or the like can be used. These acid components may be used alone or in combination of two or more, and further,
A part of oxyacid such as hydroxybenzoic acid may be copolymerized. Examples of diols include 1,2-propanediol, 1,3-propanediol, neopentyl glycol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, and 1,6. -Hexanediol, 1,2-cyclohexanedimethanol,
1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, diethylene glycol, triethylene glycol, polyalkylene glycol, 2,
2'-bis (4'-β-hydroxyethoxyphenyl)
Propane or the like can be used. Of course, a plurality of aromatic dibasic acids or a plurality of diols may be copolymerized.

In the present invention, the polymer in which the main repeating unit constituting the nonwoven fabric is ethylene-2,6-naphthalate means that at least 80 mol% of the repeating units are ethylene-2,6-naphthalate units. Preferably 8
It is 5 mol% or more, more preferably 90 mol% or more. When the ethylene-2,6-naphthalate unit is less than 80 mol% of the repeating unit, the printing durability is poor, which is not preferable. If it is 20 mol% or less, it may be modified by another copolymerization component. As a specific example of the copolymerization component, the same one as the copolymerization component of the film of the present invention can be used.

The polymer having ethylene-2,6-naphthalate as the main repeating unit constituting the film and the nonwoven fabric in the present invention uses a compound having an acid component such as a dibasic acid and an ester-forming functional group such as a diol component. Can be manufactured by the following method. For example,
After directly esterifying the acid component with the diol component,
A method in which the product of this reaction is heated under reduced pressure to polycondense while removing the excess diol component, or a dialkyl ester is used as the acid component, and after transesterification reaction between this and the diol component In the same manner as above, there is a method of producing by polycondensation. At this time, if necessary, a conventionally known alkali metal, alkaline earth metal, manganese, cobalt, zinc, antimony, germanium, titanium compound or the like can be used as a reaction catalyst. Further, a phosphorus compound can be used as the heat stabilizer.

The polymer having ethylene-2,6-naphthalate as the main repeating unit constituting the film and the nonwoven fabric in the present invention may optionally contain a flame retardant, an antioxidant, an ultraviolet absorber, an antistatic agent, a pigment, An antifoaming agent such as a dye or polysiloxane may be added.

Further, a slipperiness imparting method can be adopted. For example, a method of blending inorganic particles such as clay, mica, titanium oxide, calcium carbonate, kaolin, talc, wet or dry silica, alumina, zirconia, etc., organic particles having acrylic acid, styrene, etc. as constituent components, polyester polymerization reaction There are a method of so-called internal particles, a method of applying a surface active agent, etc., in which a catalyst and the like added at times is deposited.

The non-woven fabric constituting the base paper in the present invention is
It is preferably produced by stretching an unstretched nonwoven fabric obtained by a direct melt spinning method such as a conventionally known melt blow method or spun bond method, using a polymer whose main repeating unit is ethylene-2,6-naphthalate. can do. The intrinsic viscosity of the polyester used is usually preferably 0.3 or more, more preferably 0.4 or more, and particularly preferably 0.5 or more.

In the melt-blowing method, the unstretched nonwoven fabric is blown with hot air from the periphery of the die when the molten polymer is ejected from the die, and the extruded polymer is made finer by the hot air and then placed at an appropriate position. It is manufactured by spraying and collecting on a net conveyor to form a web. Since the web is sucked together with the hot air by the suction device provided on the net conveyor, the individual fibers are collected before being completely solidified. That is, the fibers of the web are collected while being fused to each other. By appropriately setting the collection distance between the die and the net conveyor, the fusion degree of the fibers can be adjusted. The basis weight of the web and the fiber diameter of the single yarn can be arbitrarily set by appropriately adjusting the polymer discharge amount, the hot air temperature, the hot air flow rate, the conveyor moving speed, and the like. The fibers spun by the melt blow method are finely pulverized by the pressure of hot air and solidified in a non-oriented or low-oriented state. The thickness of the fibers is not uniform, and the web is formed in a state in which the thick fibers and the thin fibers are appropriately dispersed. Further, the polymer discharged from the die is rapidly cooled from the molten state to the room temperature atmosphere, so that the polymer is solidified in a low crystalline state close to an amorphous state.

Similarly, in the spunbond method, the unstretched nonwoven fabric is obtained by pulling the polymer discharged from the die with an air ejector, colliding the obtained filament with a collision plate to open the fiber, and collecting it in a conveyor shape. Manufactured by forming a web. The basis weight of the web can be arbitrarily set by appropriately setting the polymer discharge amount and the conveyor speed. In addition, the molecular orientation of the filament can be arbitrarily adjusted by appropriately adjusting the pressure and flow rate of the ejector.
A web having a low degree of molecular orientation can be obtained by reducing the spinning speed by reducing the pressure and the flow rate. Further, by adjusting the cooling rate of the discharged polymer, a web with low crystallinity can be obtained. When produced by the spunbond method, the unstretched polyester nonwoven fabric used in the present invention is preferably spun at a spinning speed of 2500 m / min or less, more preferably 2000 m / min or less, particularly preferably 1500 m / min or less. Spinning speed is 2500m
When it is at most / minute, co-stretching with the film can be favorably carried out.

Among the above, a more preferable unstretched nonwoven fabric is a nonwoven fabric obtained by a melt blow method.

The crystallinity of the unstretched nonwoven fabric used in the present invention is usually preferably 20% or less, more preferably 15%.
It is particularly preferably 10% or less. Crystallinity is 2
When the content is 0% or less, the fusion between the fibers is good, and a good mesh body is easily formed during stretching. Also, the fusion with the film is good.

The unstretched nonwoven fabric used in the present invention is most preferably unstretched, but even if stretched, it is preferably a low stretch ratio and a low degree of orientation. Birefringence (Δ
n) is preferably 0.03 or less, more preferably 0.0
It is 2 or less, particularly preferably 0.01 or less. When the birefringence is 0.03 or less, co-stretching with the film can be favorably performed.

The film of the present invention is preferably obtained by biaxially stretching an unstretched film, and is produced by the following method using a polymer whose main repeating unit is ethylene-2,6-naphthalate. be able to. For example, a fully dried polymer may be added at 270-35.
An unstretched film can be produced by melting at 0 ° C. and extruding it on a cast drum by the T-die extrusion method. By adjusting the slit width of the die, the discharge amount of the polymer, and the rotation speed of the cast drum, an unstretched film having a desired thickness can be produced. The intrinsic viscosity of the polymer used in the film is preferably 0.40 or more, more preferably 0.50 or more, and particularly preferably 0.55 or more. When the intrinsic viscosity is 0.40 or more, the film-forming stability is high, and in particular, thin products can be easily cast.

The film and the non-woven fabric in the present invention are adhered to each other without an adhesive. The adhesion is achieved by performing the above-mentioned unstretched nonwoven fabric by extrusion casting and an unstretched film obtained before the longitudinal stretching step. The adhesion temperature is usually preferably between 80 and 170 ° C, more preferably between 100 and 150 ° C.

In the present invention, it is particularly preferable that the unstretched film and the unstretched nonwoven fabric are heat-bonded and then co-stretched. By co-stretching in a heat-bonded state, the film and the non-woven fabric can be suitably stretched without being peeled together. At this time, the fibers of the non-woven fabric are fused to each other at the entanglement points and the contact points to form a mesh body having bonding points. Further, among these bonding points, at some bonding points, a thin film extending between the fibers is formed. That is, by forming the porous support of the present invention as described above, the strength of the support is stabilized, and a porous body having a uniform open pore shape can be formed. It is possible to obtain a base paper having a balanced holding property. Further, by co-stretching the both together, the strength of the polyester non-woven fabric increases and acts as a reinforcing body, so that the film is not broken and the film forming stability is extremely excellent.

The method of co-stretching is not particularly limited, but biaxial stretching is preferred, and either sequential biaxial stretching or simultaneous biaxial stretching may be used. In the case of the sequential biaxial stretching method, it is general to stretch in the longitudinal direction and then in the transverse direction, but the stretching may be reversed. Stretching temperature is 100-180
° C is preferred and 110-150 ° C is more preferred. The stretching ratio is not particularly limited and may be appropriately determined depending on the kind of the polymer for polyester film to be used, the sensitivity required for the base paper, etc., but is usually preferably 2 to 10 times in each of the length and width, more preferably 3 to 10 times is appropriate. Further, after biaxial stretching, it may be re-stretched longitudinally or laterally or longitudinally and laterally.

After that, the base paper of the present invention after biaxial stretching may be heat treated. The heat treatment temperature is not particularly limited and may be appropriately determined, but usually 80 to 260 ° C., and the time is preferably 0.5 to 60 seconds.

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 120 ° C.
Aging for 5 minutes to 1 week is also possible. When such aging is adopted, curling and wrinkling are less likely to occur during storage of the base paper or in the printing machine, which is particularly preferable.

The area fraction of the open pores obtained by directly observing the support surface of the base paper of the present invention by the bright field transmission method of an optical microscope is preferably 5 to 80%, more preferably 10 to 50%.
Particularly preferably, it is 10 to 30%. If the area fraction of the openings is 5% or more, the ink permeability is high, and if it is 80% or less, the ink retention is good. Further, when the apertures observed by the bright field transmission method of an optical microscope are regarded as circles, the average value of the equivalent circle diameter is preferably 5 to 100 μm.
m, more preferably 10 to 60 μm, particularly preferably 1
It is 0 to 30 μm. If the average diameter is 5 μm or more, the ink permeability is high, and if the average diameter is 100 μm or less, the ink holding property is good.

The average fiber diameter of the nonwoven fabric of the present invention is 1 to 15 μm.
m, preferably 2 to 12 μm, more preferably 3
10 to 10 μm. If the average fiber diameter is less than 1 μm, wrinkles are easily formed in the base paper, unperforated at the time of perforation, or ink permeation is impeded at the time of printing, which is not preferable. Further, if it exceeds 15 μm, the flatness of the base paper is deteriorated and the perforations become uneven, which is not preferable.

The basis weight of the non-woven fabric constituting the base paper of the present invention is
It is preferably 1 to 30 g / m ² , and more preferably 2
˜20 g / m ² , particularly preferably 3 to 16 g / m ² . The nonwoven fabric of the present invention is preferably stretch-oriented, and the birefringence (Δn) of each fiber is preferably 0.1 or more, more preferably 0.12 or more, and particularly preferably 0.1.
It is 14 or more.

The crystallinity of the nonwoven fabric of the present invention is preferably 15% or more, more preferably 20% or more, and particularly preferably 25% or more.

The film constituting the base paper of the present invention is preferably a biaxially stretched film, and the thickness is appropriately determined depending on the sensitivity required for the base paper, but usually 0.1 to 5
μm, preferably 0.1 to 2 μm, and more preferably 0.1 to 1.7 μm.

The film constituting the base paper of the present invention preferably has a crystal melting energy (ΔHu) of 3 to 13 cal / g, more preferably 5 to 12 cal / g.

The melting point (Tm ₁ ) of the film constituting the base paper of the present invention and the melting point (Tm ₂ ) of the non-woven fabric are preferably Tm ₁ ≤Tm ₂ .

The peel strength between the film and the nonwoven fabric constituting the base paper of the present invention is preferably 3 g / cm or more, more preferably 5 g / cm or more, particularly preferably 10 g / cm.
That is all.

Further, the tensile elastic modulus in the longitudinal direction of the base paper of the present invention is preferably 0.20 kg / cm or more, more preferably 0.25 kg / cm or more, particularly preferably 0.3.
It is 0 kg / cm or more.

In the present invention, in order to prevent fusion with a thermal head or the like, it is preferable to provide a release layer on the surface of the film opposite to the nonwoven fabric. As the method, after heat-bonding the unstretched film and the unstretched nonwoven fabric, before or after the biaxial co-stretching, or in the process in the middle, on the other surface of the film, to apply a release agent Is.

As the release agent used in the base paper of the present invention, one made of silicone oil, silicone resin, fluorine resin, surfactant or the like can be used.

In the base paper of the present invention, various additives may be used together with the release agent within the range not impairing the effects of the present invention. For example, antistatic agents, heat-resistant agents, antioxidants, organic particles, inorganic particles, pigments and the like can be used.

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

The thickness of the release agent layer is preferably 0.005 μm.
m or more and 0.4 μm or less, more preferably 0.01 μm or more and 0.4 μm or less. The thickness of the release agent layer is 0.4 μm
If it is below, the running property at the time of perforation is good and the contamination of the head is small.

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

The release agent may be applied at any stage before or after stretching the film. In order to bring out the effect of the present invention more remarkably, it is particularly preferable to apply before stretching. 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 coated surface may be subjected to corona discharge treatment in air or other various atmospheres before coating with the release agent.

[0043]

EXAMPLES Next, a method of measuring characteristics and an evaluation method of the present invention will be described. (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.
It is determined from the area of the film when it is melted using a mold. 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). Same DSC
In (indium) was measured under the condition of
Is calculated to be 6.8 cal / g by the following formula. 6.8 × a / b = ΔHu (cal / g)

(3) Average fiber diameter Magnification 2000 at 10 arbitrary points of the sample with an electron microscope
Double 10 photographs were taken, the diameter of any 15 fibers was measured per photograph, and this was carried out for 10 photographs, and expressed as an average of the diameter of 150 fibers in total.

(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] It was measured at 25 ° C. using o-chlorophenol as a solvent.

(6) Crystallinity (%) A sample was placed in a density gradient tube made of a mixed solution of n-heptane and carbon tetrachloride, and the value was read after 10 hours or more to obtain the density. Crystallinity 0% density 1.325g / c
m ³ , density of 100% crystallinity of 1.407 g / cm ³
As, the crystallinity of the sample was calculated.

(7) Birefringence (Δn) Using a polarization microscope, a sodium lamp was used as a light source, and the sample was immersed in α-promnaphthalene, and the retardation was calculated from the Berek convensor method.

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

(9) Average value (μm) of equivalent circular diameters of the apertures of the support The surface of the support of the base paper was directly observed by the bright-field transmission method of an optical microscope, and an image analysis device compatible with Hi-Vision manufactured by Pierce Co., Ltd. Using a monitor with a monitor magnification of 240 times, black and white reversal processing,
The equivalent circular diameter of the aperture was measured and the average value was calculated. The measurement was performed at 10 arbitrary measurement points, and the average value was shown.

(10) Peel strength (g / cm) A cellophane tape was attached to the film surface to reinforce, and the peel strength between the film and the porous support was measured according to JIS-K-6854.
The 180-degree peel test method according to

(11) Tensile Modulus The base paper was cut in the longitudinal direction with a single-edged razor to obtain a width of 2c.
10 samples of m and 15 cm in length were collected. The sample was placed in a Tensilon tensile tester (manufactured by Toyo Sokki) with a test length of 5
Grip at m, pull at a test speed of 5 mm / min, and record the load-elongation relationship on a recorder. The elastic modulus was calculated from the initial linear portion of load-elongation and expressed as the average of 10 samples. In particular, the tensile modulus was expressed by the load per unit width, that is, kg / cm.

(12) Evaluation of printability The prepared base paper was supplied to a printing machine lithograph (SR7200) manufactured by Riso Kagaku Kogyo Co., Ltd., and black solid (10) on A4 size with a side of 10 mm was applied by a thermal head type plate making method. A master was created by making a grid on the entire surface. Using this master, the Macbeth density of printed matter and printing durability during large-scale printing (1000 sheets) were evaluated. The judgment of printing durability is ◎ if there is no tear or elongation on the master, ○ if there is no tear but elongation of 1% or less, ○, if there is no tear but elongation exceeds 1% △ When the film was torn, peeled off between the film and the support, or had a large elongation, it was rated as x.

Example 1 [Production of porous support] Pore diameter 0.35 mm, number of pores 100
Using a rectangular spinneret, a polyethylene-2,6-naphthalate raw material (intrinsic viscosity: 0.5, Tm: 265 ° C.) was spun by a melt-blowing method at a spinneret temperature of 305 ° C. and a discharge rate of 30 g / min. The fibers were collected on a conveyor at a collection distance of 13 cm and wound up to produce an unstretched nonwoven fabric having a fiber basis weight of 160 g / m ² . The average fiber diameter of the non-woven fabric is 8.9 μm,
The crystallinity was 2% and the birefringence (Δn) was 0.005.

[Manufacturing of base paper] Next, the average particle diameter is 1.5.
Polyethylene containing 0.4% by weight of silica of μm
2,6-naphthalate (intrinsic viscosity: 0.6, Tm: 26
5 ° C) is pre-crystallized at 150 ° C, dried under reduced pressure at 180 ° C for 3 hours in a rotary dryer, and extruded at a T-die spinneret temperature of 295 ° C using an extruder having a screw diameter of 40 mm, and having a diameter of 300 mm. 11μ thickness cast on a cooling drum
m unstretched film was prepared.

On the unstretched film, the above unstretched non-woven fabric was placed, supplied to a heating roll and thermocompression bonded at a roll temperature of 120 ° C. The laminated sheet thus obtained was stretched 4.0 times in the length direction by a heating roll at 140 ° C., then fed into a tenter type transverse stretching machine, stretched 4.0 times in the width direction at 135 ° C., and further in a tenter. At 150 ° C. for 10 seconds to prepare a heat-sensitive stencil sheet. On the film side of the base paper, silicone oil (Toray
An aqueous emulsion of SH-200 manufactured by Dow Corning Silicone Co., Ltd. was applied with a gravure coater to a dry weight of 0.1 g / m ² . The fiber basis weight of the obtained base paper was 10 g / m ² , and the average fiber diameter was 4.5 μm. The thickness of the film alone was 0.7 μm.
When the base paper was observed with an optical microscope, the support had a reticulated body in which fibers were fused to each other.

[Evaluation Results] As summarized in Table 1, when the printability of the base paper finally obtained was evaluated, the base paper was excellent in printing durability and good.

Comparative Example 1 Polyethylene-2,6-naphthalate containing 0.4% by weight of silica having an average particle diameter of 1.5 μm (intrinsic viscosity: 0.
6, Tm: 265 ° C.) at 150 ° C., and then dried under reduced pressure at 180 ° C. for 3 hours in a rotary dryer, and a T-die die temperature of 29 using a screw diameter 40 mm extruder.
It was extruded at 5 ° C. and cast on a cooling drum having a diameter of 300 mm to obtain an unstretched film having a thickness of 11 μm.

The obtained unstretched film was stretched 4.0 times in the length direction with a heating roll at 140 ° C., then fed into a tenter type transverse stretching machine, and stretched 4.0 times in the width direction at 135 ° C. Further, the film was heat-treated in a tenter at 150 ° C. for 10 seconds to obtain a film for heat-sensitive stencil having a thickness of 0.7 μm. Silicone oil (SH-made by Toray Dow Corning Silicone Co., Ltd.)
The aqueous emulsion of 200) was applied by a gravure coater at a weight of 0.1 g / m ² after drying. The obtained film and a thin paper having a basis weight of 10 g / m ² containing Manila hemp as a main component were laminated using a vinyl acetate resin to obtain a base paper. The obtained base paper had insufficient printing durability.

Comparative Example 2 [Production of porous support] Pore diameter 0.35 mm, number of pores 100
Polyethylene terephthalate raw material (intrinsic viscosity: 0.5, Tm: 257 ° C.) was spun by a melt-blowing method at a spinneret temperature of 280 ° C. and a discharge rate of 30 g / min using individual rectangular spinnerets with a collection distance of 15 cm. The fibers were collected on a conveyor and wound up to prepare an unstretched nonwoven fabric having a fiber areal weight of 160 g / m ² . The nonwoven fabric had an average fiber diameter of 8.9 μm, a crystallinity of 2% and a birefringence (Δn) of 0.005.

[Production of base paper] Next, the average particle diameter is 1.5.
20 parts by weight of polyethylene terephthalate containing 2% by weight of silica having a particle size of 80 μm and 80 parts by weight of a copolymer of ethylene terephthalate and ethylene isophthalate (copolymerization of isophthalic acid 17.5 mol%) (isophthalic acid 14 after mixing)
Mol% copolymerization), dried under reduced pressure at 170 ° C. for 3 hours in a rotary dryer, extruded at a T-die mouthpiece temperature of 280 ° C. using an extruder with a screw diameter of 40 mm, and cast on a cooling drum with a diameter of 300 mm to be thick. An unstretched film having a size of 11 μm was prepared.

On the unstretched film, the above-mentioned unstretched non-woven fabric was placed, supplied to a heating roll and thermocompression bonded at a roll temperature of 80 ° C. The laminated sheet thus obtained was stretched 4.0 times in the length direction with a heating roll at 90 ° C., then fed to a tenter type transverse stretching machine, stretched 4.0 times in the width direction at 95 ° C., and further in a tenter. At 120 ° C. for 10 seconds to prepare a heat-sensitive stencil sheet. An aqueous emulsion of silicone oil (SH-200 manufactured by Toray Dow Corning Silicone Co., Ltd.) was used at the inlet of the tenter on the film surface of the base paper with a gravure coater to give a weight of 0.1 g / m ² after drying. Applied. The fiber basis weight of the obtained base paper was 10 g / m ² , and the average fiber diameter was 4.5 μm. The thickness of the film alone was 0.7 μm. When the base paper was observed with an optical microscope, the support had a reticulated body in which fibers were fused to each other.

[Evaluation Results] As summarized in Table 1, when the printability of the base paper finally obtained was evaluated, the base paper was inferior in printing durability.

Example 2 Copolymerized polyethylene-2,6-naphthalate containing 5 mol% of ethylene isophthalate units containing 0.4% by weight of silica having an average particle size of 1.5 μm was used in a twin-screw extruder. The mixture was melt-kneaded, extruded and cut to obtain a copolymer polyester resin raw material (Tm = 250 ° C.). Using the obtained raw material, it was dried under reduced pressure at 170 ° C. for 3 hours in a rotary dryer, extruded at a T-die base temperature of 290 ° C. using an extruder having a screw diameter of 40 mm, and cast on a cooling drum having a diameter of 300 mm. An unstretched film having a thickness of 11 μm was prepared.

On the unstretched film, the unstretched nonwoven fabric of Example 1 was overlaid and fed to a heating roll to obtain a roll temperature of 110.
Thermocompression bonding was performed at ° C. The laminated sheet thus obtained is
The film was stretched 4.0 times in the length direction with a heating roll at ℃, and then fed into a tenter type transverse stretching machine, where it was stretched at 135 ° C. in the width direction at 4.
It was stretched 0 times and further heat-treated in a tenter at 150 ° C. for 10 seconds to prepare a heat-sensitive stencil sheet. Silicone oil (SH-20 manufactured by Toray Dow Corning Silicone Co., Ltd.) is provided on the film surface of the base paper at the inlet of the tenter.
The aqueous emulsion of 0) was applied with a gravure coater to a dry weight of 0.1 g / m ² . The fiber basis weight of the obtained base paper was 10 g / m ² , and the average fiber diameter was 4.5 μm. The thickness of the film alone was 0.7 μm.

[Evaluation Results] As shown in Table 1, when the printability of the base paper finally obtained was evaluated, the base paper had high printing durability and was good.

Example 3 [Production of porous support] Pore diameter 0.25 mm, pore number 100
A polyethylene-2,6-naphthalate raw material ([η] = 0.6) was used at a discharge rate of 1000 g / min using 0 rectangular die.
(0, Tm = 265 ° C.) was spun at a melting temperature of 305 ° C. and dispersed and collected on a conveyor by an air ejector at a spinning speed of 1500 m / min to prepare a low orientation unstretched nonwoven fabric having a fiber basis weight of 160 g / m ² . . The average fiber diameter of the non-woven fiber is 1
8 μm, crystallinity 5%, birefringence (Δn) 0.009
Met.

[Manufacturing of base paper] Next, the average particle size is 1.5.
Polyethylene containing 0.4% by weight of silica of μm
2,6-naphthalate (intrinsic viscosity: 0.6, Tm: 26
5 ° C) is pre-crystallized at 150 ° C, dried under reduced pressure at 180 ° C for 3 hours in a rotary dryer, and extruded at a T-die spinneret temperature of 295 ° C using an extruder having a screw diameter of 40 mm, and having a diameter of 300 mm. 11μ thickness cast on a cooling drum
m unstretched film was prepared.

The unstretched nonwoven fabric was placed on the unstretched film, supplied to a heating roll and thermocompression bonded at a roll temperature of 120 ° C. The laminated sheet thus obtained was stretched 4.0 times in the length direction by a heating roll at 140 ° C., then fed into a tenter type transverse stretching machine, stretched 4.0 times in the width direction at 135 ° C., and further in a tenter. At 150 ° C. for 10 seconds to prepare a heat-sensitive stencil sheet. On the film side of the base paper, silicone oil (Toray
An aqueous emulsion of SH-200 manufactured by Dow Corning Silicone Co., Ltd. was applied with a gravure coater to a dry weight of 0.1 g / m ² . The fiber basis weight of the obtained base paper was 10 g / m ² , and the average fiber diameter was 9.0 μm. The thickness of the film alone was 0.7 μm.
When the base paper was observed with an optical microscope, the support had a reticulated body in which fibers were fused to each other.

[Evaluation Results] As summarized in Table 1, when the printability of the base paper finally obtained was evaluated, the base paper had high printing durability and was good.

Example 4 and Comparative Example 3 A base paper was prepared in the same manner as in Example 1 except that the discharge amount was changed and the average fiber diameter of the non-woven fabric was changed as shown in Table 1 in the production of the non-woven fabric.

[Evaluation Results] As summarized in Table 1, the base paper of the present invention has good printing durability, whereas when the average fiber diameter is outside the range of the present invention, the sensitivity is lowered, Printing durability is poor.

Examples 5 to 7 Base papers were prepared in the same manner as in Example 1 except that the film thickness was changed. As shown in Table 1, when the printability of the base paper finally obtained was evaluated, the base paper had good printing durability.

[0075]

[Table 1]

[0076]

The present invention has the above-mentioned structure,
Since it is possible to form a support having a uniform aperture form, it is possible to form a base paper with stable strength, and the printed matter obtained by stencil printing using this base paper has high image quality and print sharpness. And has excellent printing durability.

Claims (2)

[Claims] 1. The main repeating unit is ethylene-2,6.
A film composed of a polymer which is a naphthalate and a non-woven fabric composed of a polymer whose main repeating unit is an ethylene-2,6-naphthalate are bonded together without an adhesive, and which constitutes a non-woven fabric. A base paper for heat-sensitive stencil printing, characterized in that the average fiber diameter of the fibers is 1 to 15 μm. 2. The tensile elastic modulus in the longitudinal direction is 0.2 kg / c.
The heat-sensitive stencil printing base paper according to claim 1, which has a length of m or more.