JP3329144B2 - Base paper for heat-sensitive stencil printing - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat-sensitive stencil sheet. More specifically, the present invention relates to a heat-sensitive stencil sheet having excellent sensitivity and printing durability, which is formed by perforating plate making by pulse irradiation such as flash irradiation, infrared irradiation, or laser beam, or by contact with a thermal head.

[0002]

2. Description of the Related Art As heat-sensitive stencil base paper (hereinafter sometimes simply referred to as base paper), natural fibers, chemical fibers or synthetic fibers or thermoplastic fibers such as vinylidene chloride-based films and polyethylene terephthalate-based films can be used. There is known a structure in which a porous support composed of thin paper, nonwoven fabric, gauze, or the like obtained by mixing them is bonded with an adhesive (for example, Japanese Patent Publication No. 41-6815).
JP, JP-A-51-2513, JP-A-57-1
No. 82495).

However, these conventional base papers have the following disadvantages. That is, (1) Since the film and the porous support are adhered to each other using an adhesive, the transmission of the ink is hindered by the adhesive, resulting in poor image clarity. (2) Regarding the adhesive used itself, for example, acrylic resin and vinyl acetate resin adhesive are easy to soften, swell and dissolve with printing ink, so they have poor ink resistance and use thermosetting adhesive. In this case, the uncured material is apt to remain, so that the thermal head is likely to be fused during plate making. (3) Further, when an adhesive is used, a bonding step is indispensable in a base paper manufacturing process, and a solvent is used at the time of applying the adhesive, so that a solvent recovery facility is required, resulting in an increase in cost. (4) Further, it is necessary to handle a thin film in the bonding step, so that troubles such as tearing of the film and wrinkles are liable to occur, and the yield is reduced.

In order to improve these drawbacks, proposals have been made to minimize the amount of adhesive used (for example, Japanese Patent Application Laid-Open No. 58-147396, Japanese Patent Application Laid-Open No.
However, the above-mentioned disadvantages could not be completely eliminated.

[0005] As a method without using an adhesive, Japanese Patent Application Laid-Open No. Hei 4-212891 is characterized in that a synthetic fiber is sprinkled on one side of a thermoplastic resin film and a fiber layer formed by thermocompression bonding is formed. Has been proposed. However, since this method is a method in which synthetic fibers having a length of 50 mm or less are sprayed by wind or static electricity, the dispersion of the fibers becomes non-uniform, thus causing unevenness in ink permeability and shading in printed matter. . 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 are generated at the time of transporting the film or fibers with insufficient adhesion become foreign matters. In order to improve the adhesiveness, it has been proposed to mix a binder fiber into the fiber layer or to apply a small amount of an adhesive to the film surface.However, if the binder fiber or the adhesive is used, ink permeability is impaired, As a result, there is a disadvantage that the image clarity is reduced.

Further, Japanese Patent Application Laid-Open No. 2-107488 discloses a heat-sensitive stencil sheet having a thermoplastic film and a non-woven fabric mainly composed of continuous filaments for the purpose of improving image clarity and printing durability. However, in terms of the balance between ink permeability and printing durability,
It was still inadequate.

[0007] From such a background, a completely novel base paper which does not use an adhesive and has a polyester film and a porous support made of polyester fiber directly adhered thereto has been proposed (JP-A-6-305273). No.). However, it has been found that there is a problem that the base paper is stretched or torn when mass printing is performed due to insufficient strength of the base paper.

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to solve the 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-mentioned object, a heat-sensitive stencil sheet according to the present invention comprises a film comprising a polymer whose main repeating unit is ethylene-2,6-naphthalate; A nonwoven fabric composed of a polymer whose main repeating unit is ethylene-2,6-naphthalate is adhered without an adhesive, and the average fiber diameter of the fibers constituting the nonwoven fabric is 1 to 1
The thickness is 5 μm.

In the present invention, the polymer in which the main repeating unit constituting the film is ethylene-2,6-naphthalate is such that at least 70 mol% of the repeating units are ethylene-2,6-naphthalate units. It is preferably at least 80 mol%, more preferably at least 85 mol%. If the content of the ethylene-2,6-naphthalate unit is less than 70 mol% of the repeating unit, the printing durability is poor, so that it 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 copolymer 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, as the aromatic dicarboxylic acid, for example, terephthalic acid, isophthalic acid, phthalic acid, 1,4-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid,
Examples of the dicarboxylic acid having a metal sulfonate such as 4'-diphenyldicarboxylic acid, 4,4'-diphenylether dicarboxylic acid, 4,4'-diphenylsulfondicarboxylic acid, and 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.
An oxyacid such as hydroxybenzoic acid may be partially copolymerized. Examples of the 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 is such that at least 80 mol% of the repeating units are ethylene-2,6-naphthalate units. Preferably 8
It is at least 5 mol%, more preferably at least 90 mol%. When the amount of the ethylene-2,6-naphthalate unit is less than 80% by mole of the repeating unit, the printing durability is poor, which is not preferable. If it is 20 mol% or less, it may be modified with another copolymer component. As specific examples of the copolymer component, those similar to the copolymer component of the film of the present invention can be used.

The polymer in which the main repeating unit constituting the film and the nonwoven fabric of the present invention is ethylene-2,6-naphthalate is 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 produced by heating under reduced pressure to conduct polycondensation while removing the excess diol component, or a dialkyl ester is used as an acid component, and a transesterification reaction is performed between the dialkyl ester and the diol component. And a method of producing by polycondensation in the same manner as described above. In this case, 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 a heat stabilizer.

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

Furthermore, a method for imparting lubricity may be employed. For example, a method of blending inorganic particles such as clay, mica, titanium oxide, calcium carbonate, kaolin, talc, wet or dry silica, alumina, zirconia, organic particles containing acrylic acid, styrene, etc., a polyester polymerization reaction There are a method using so-called internal particles for precipitating a catalyst and the like to be added sometimes, and a method using a surfactant.

In the present invention, the nonwoven fabric constituting the base paper is
It is preferably manufactured by using a polymer whose main repeating unit is ethylene-2,6-naphthalate to stretch an unstretched nonwoven fabric obtained by a conventional direct melt spinning method such as a melt blow method or a spun bond method. 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 blow method, when the molten polymer is discharged from the die, hot air is blown from the peripheral portion of the die, the polymer discharged by the hot air is made finer, 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 they are completely solidified. That is, the fibers of the web are collected in a state where they are fused to each other. By appropriately setting the collection distance between the base and the net conveyor, the degree of fusion of the fibers can be adjusted. Also, by appropriately adjusting the amount of polymer discharged, the temperature of hot air, the flow rate of hot air, the moving speed of the conveyor, and the like, the basis weight of the web and the diameter of the single yarn fiber can be set as desired. The fibers spun by the melt blow method are fined 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 where the thick fibers and the fine fibers are appropriately dispersed. Further, the polymer discharged from the die is rapidly cooled from a molten state to an atmosphere at room temperature, so that the polymer is solidified in a near-amorphous, low-crystal state.

Similarly, in the spunbonding method, the unstretched nonwoven fabric is drawn by an air ejector on a polymer discharged from a die, and the obtained filaments collide with a collision plate to spread the fibers and are collected in a conveyor shape. It is manufactured by forming a web. The web weight can be arbitrarily set by appropriately setting the polymer discharge amount and the conveyor speed. In addition, by appropriately adjusting the pressure and the flow rate of the ejector, the molecular orientation state of the filament can be arbitrarily adjusted.
By reducing the spinning speed by reducing the pressure and the flow rate, a web having a low degree of molecular orientation can be obtained. Further, by adjusting the cooling rate of the discharged polymer, a web having low crystallinity can be obtained. When manufactured by the spun bond method, the undrawn 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, and particularly preferably 1500 m / min or less. Spinning speed 2500m
/ Min or less, co-stretching with the film can be performed favorably.

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%.
Or less, particularly preferably 10% or less. Crystallinity 2
When the content is 0% or less, fusion between the fibers is good, and a good network is easily formed at the time of stretching. Also, the fusion with the film is good.

The unstretched nonwoven fabric used in the present invention is most preferably unstretched. However, even if it is stretched, it is preferably one having a low magnification and a low degree of orientation. Usually, birefringence (Δ
n) is preferably 0.03 or less, more preferably 0.03 or less.
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 in which the main repeating unit is ethylene-2,6-naphthalate. be able to. For example, a fully dried polymer may be 270-35.
An unstretched film can be produced by melting at 0 ° C. and extruding onto a cast drum by a T-die extrusion method. An unstretched film having a desired thickness can be produced by adjusting the slit width of the die, the discharge amount of the polymer, and the rotation speed of the cast drum. The intrinsic viscosity of the polymer used for 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 particularly, a thin material can be easily cast.

In the present invention, the film and the nonwoven fabric are adhered without using an adhesive. Adhesion is achieved by performing the above-mentioned unstretched nonwoven fabric with an unstretched film obtained by extrusion-casting at a stage before the longitudinal stretching step. The bonding temperature is usually preferably between 80 and 170C, more preferably between 100 and 150C.

In the present invention, it is particularly preferable that the unstretched film and the unstretched nonwoven fabric are co-stretched after heat bonding. By co-stretching in the state of heat bonding, the film and the nonwoven fabric can be stretched favorably without peeling off integrally. At this time, the fibers of the nonwoven fabric are fused to each other at the entanglement points and the contact points to form a net having adhesion points. Further, at some of these bonding points, a thin film that extends 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 opening form can be formed. It can be used as a base paper having a good balance of retention. Further, by co-stretching both, the strength of the polyester non-woven fabric is increased and the non-woven fabric functions as a reinforcing member, 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 any of a sequential biaxial stretching method and a simultaneous biaxial stretching method may be used. In the case of the sequential biaxial stretching method, stretching is generally performed in the order of the longitudinal direction and the transverse direction, but may be performed in the opposite direction. Stretching temperature is 100-180
C is preferable, and 110 to 150 C is more preferable. The stretching ratio is not particularly limited, and is appropriately determined depending on the type of the polymer for the polyester film to be used, the sensitivity required for the base paper, and the like. Usually, the length and width are preferably 2 to 10 times, more preferably 3 to 10 times. Ten times is appropriate. After biaxial stretching, the film may be stretched longitudinally or horizontally, or vertically and horizontally.

Thereafter, the base paper of the present invention after biaxial stretching may be subjected to a heat treatment. The heat treatment temperature is not particularly limited and is determined as appropriate, but is usually from 80 to 260 ° C. and the time is preferably from about 0.5 to 60 seconds.

After the base paper obtained by the heat treatment is once cooled to about room temperature, it is further cooled at a relatively low temperature of 40 to 120 ° C.
It can be aged for 5 minutes to 1 week. When such aging is employed, curling and wrinkles are less likely to occur during storage of the base paper or in the printing press, and it is particularly preferable.

The area fraction of the apertures obtained by directly observing the support surface of the base paper of the present invention by a bright-field transmission method using an optical microscope is preferably 5 to 80%, more preferably 10 to 50%.
Particularly preferably, it is 10 to 30%. When the area fraction of the opening is 5% or more, the ink permeability is high, and when the area fraction is 80% or less, the ink retention is good. Further, when the opening portion observed by the bright field transmission method of the optical microscope is regarded as a circle, the average value of the equivalent circular diameter is preferably 5 to 100 μm.
m, more preferably 10 to 60 μm, particularly preferably 1 to 60 μm.
0 to 30 μm. When the average diameter is 5 μm or more, the ink permeability is high, and when the average diameter is 100 μm or less, the ink retention 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 to 12 μm.
〜１０10 μm. If the average fiber diameter is less than 1 μm, the base paper is likely to be wrinkled, which is unpunched at the time of perforation, or impairs the transmission of ink at the time of printing. On the other hand, when the thickness exceeds 15 μm, the flatness of the base paper is reduced, and the perforations are uneven, which is not preferable.

The basis weight of the nonwoven fabric constituting the base paper of the present invention is as follows:
Preferably it is 1 to 30 g / m ² , more preferably ² g / m 2.
-20 g / m ² , particularly preferably 3-16 g / m ² . The nonwoven fabric of the present invention is preferably stretched and 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 or more.
14 or more.

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

The film constituting the base paper of the present invention is preferably a biaxially stretched film, and the thickness is appropriately determined according to the sensitivity required for the base paper, but is 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 nonwoven fabric are preferably such that Tm ₁ ≦ Tm ₂ .

The peel strength between the film constituting the base paper of the present invention and the nonwoven fabric 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 modulus of the base paper of the present invention in the longitudinal direction is preferably 0.20 kg / cm or more, more preferably 0.25 kg / cm or more, and particularly preferably 0.3 kg / cm or more.
0 kg / cm or more.

In the present invention, a release layer is preferably provided on the surface of the film opposite to the nonwoven fabric in order to prevent fusion with a thermal head or the like. As a method, a method in which the unstretched film and the unstretched nonwoven fabric are thermally bonded, and a releasing agent is applied to the other surface of the film before or after biaxial co-stretching or in the middle of the process. It is.

As the release agent used for the base paper of the present invention, those composed of silicone oil, silicone resin, fluorine resin, surfactant and the like can be used.

The base paper of the present invention may contain various additives together with the release agent within a range not to impair the effects of the present invention. For example, an antistatic agent, a heat-resistant agent, an antioxidant, organic particles, inorganic particles, a pigment, and the like can be used.

Various additives such as a dispersing aid, a surfactant, a preservative and an antifoaming agent 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 to 0.4 μm, more preferably 0.01 μm to 0.4 μm. The thickness of the release agent layer is 0.4 μm
If it is below, the running property at the time of drilling is good and the contamination of the head is small.

In the present invention, when a release agent layer is applied, 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. In order to more remarkably exhibit the effects of the present invention, it is particularly preferable to apply the composition before stretching. The application method is not particularly limited, but application is preferably performed using a roll coater, a gravure coater, a reverse coater, a bar coater, or the like. Before the release agent is applied, the surface to be applied may be subjected to a corona discharge treatment in air or other various atmospheres, if necessary.

[0043]

Next, a method for measuring and evaluating characteristics according to the present invention will be described. (1) Melting point (Tm, ° C) Differential scanning calorimeter RDC220 manufactured by Seiko Electronics Industry Co., Ltd.
Using a mold, a sample of 5 mg was collected, and the rate of temperature rise from room temperature was 20
It was determined from the peak temperature of the endothermic curve when the temperature was raised at a rate of ° C./min.

(2) Crystal melting energy (ΔHu) Differential scanning calorimeter RDC220 manufactured by Seiko Instruments Inc.
It is determined from the area of the film at the time of melting using a mold. This area is shifted from the baseline to the absorption side by increasing the temperature, and is the area until the temperature returns to the baseline position when the temperature is further increased.The area from the melting start temperature position to the end position is connected by a straight line. (A) is obtained. Same DSC
In (indium) was measured under the following conditions, and the area (b)
Is calculated as 6.8 cal / g by the following equation. 6.8 × a / b = ΔHu (cal / g)

(3) Average Fiber Diameter Any 10 points of the sample were observed under an electron microscope at a magnification of 2000.
Ten photographs were taken at 1: 1 magnification, and the diameter of any fifteen fibers was measured for each photograph. The diameter was measured for ten photographs, and the average of the fiber diameter of a total of 150 fibers was expressed.

(4) Fiber weight (g / m ² ) A test piece of 20 cm × 20 cm was taken and its weight was measured and converted to the weight per m ² .

(5) Intrinsic viscosity [η] Measured at 25 ° C. using o-chlorophenol as a solvent.

(6) Crystallinity (%) A sample was put into a density gradient tube composed of a mixed solution of n-heptane and carbon tetrachloride, and the density was determined by reading the value after 10 hours or more. 1.325 g / c density at 0% crystallinity
m ³ , a density of 100% crystallinity is 1.407 g / cm ³
The crystallinity of the sample was calculated.

(7) Birefringence (Δn) Using a polarizing 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 Berk conven- sator method.

(8) Area Fraction (%) of Perforated Portion of Support The surface of the support of the base paper was directly observed by a bright-field transmission method using an optical microscope, and the image was analyzed using a Pierce Hi-Vision compatible image analyzer. The area fraction of the opening was determined at a monitor magnification of 240 times. The area fraction was determined for 10 arbitrary measurement points and represented by the average value.

(9) Average value (μm) of the equivalent circular diameter of the opening of the supporter The surface of the supporter of the base paper was directly observed by a bright-field transmission method using an optical microscope, and an image analyzer for Hi-Vision manufactured by Pierce Co., Ltd. , Using the monitor magnification of 240 times, black and white reversal processing,
The equivalent circular diameter of the opening was measured, and the average value was determined. Measurement was performed at 10 arbitrary measurement points, and the average value was shown.

(10) Peel strength (g / cm) A cellophane tape was applied to the film surface for reinforcement, and the peel strength between the film and the porous support was measured according to JIS-K-6854.
It was measured by a 180-degree peeling 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 2c.
m, 10 samples of 15 cm length were collected. The sample was tested on a Tensilon tensile tester (manufactured by Toyo Sokki) with a test length of 5c
m, and pulled at a test speed of 5 mm / min, and the load-elongation relationship is recorded on a recorder. The elastic modulus was determined from the initial linear portion of the load-elongation and expressed as an average of 10 samples. In particular, the tensile modulus was represented by a load per unit width, that is, kg / cm.

(12) Evaluation of printability The base paper produced was supplied to a printing machine lithograph (SR7200) manufactured by Riso Kagaku Kogyo KK, and black solid (を) with a side of 10 mm was printed on an A4 size paper by a thermal head plate making method. A master was created by making a plate over the entire surface. The master was used to evaluate the Macbeth density of the printed matter and the printing durability during mass printing (1000 sheets). The printing durability was judged as ◎ when the master had no tear or elongation, ○ when there was no tear but elongation of 1% or less, and △ when there was no tear but elongation exceeded 1%. When the film was torn, peeled between the film and the support, or had a large elongation, it was evaluated as x.

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

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

The unstretched nonwoven fabric was placed on the unstretched film, supplied to a heating roll, and thermocompressed 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 sent to a tenter type horizontal stretching machine, stretched 4.0 times in the width direction at 135 ° C., and further expanded in the tenter. At 150 ° C. for 10 seconds to produce a heat-sensitive stencil sheet. At the entrance of the tenter, a silicone oil (Toray
An aqueous emulsion of Dow Corning Silicone Co., Ltd. (SH-200) was applied using a gravure coater at a weight of 0.1 g / m ² after drying. The 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 was found to have a network formed by fusion of fibers.

[Evaluation Results] As summarized in Table 1, when the printability was evaluated using the finally obtained base paper, 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: 0.1%).
6, Tm: 265 ° C.) was pre-crystallized at 150 ° C., and then dried under reduced pressure at 180 ° C. for 3 hours using a rotary drier, and the T die die temperature was 29 using an extruder having a screw diameter of 40 mm.
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 by a heating roll at 140 ° C., then sent to a tenter type transverse stretching machine, and stretched 4.0 times in the width direction at 135 ° C. Then, the film was heat-treated in a tenter at 150 ° C. for 10 seconds to obtain a heat-sensitive stencil film having a thickness of 0.7 μm. One side of the film has a silicone oil (SH- made by Dow Corning Toray Silicone Co., Ltd.) at the entrance of the tenter.
The aqueous emulsion of (200) was applied using a gravure coater to a weight after drying of 0.1 g / m ² . The obtained film and thin paper having a basis weight of 10 g / m ² containing Manila hemp as a main component were bonded together using a vinyl acetate resin to obtain a base paper. The obtained base paper had insufficient printing durability.

Comparative Example 2 [Production of a porous support] A pore diameter of 0.35 mm and a number of holes of 100
Using a rectangular spinneret, a polyethylene terephthalate raw material (intrinsic viscosity: 0.5, Tm: 257 ° C.) is spun by a melt blow method at a die temperature of 280 ° C. and a discharge rate of 30 g / min. The fibers were collected and wound on a conveyor to produce an unstretched nonwoven fabric having a fiber weight of 160 g / m ² . The average fiber diameter of the nonwoven fabric was 8.9 μm, the crystallinity was 2%, and the birefringence (Δn) was 0.005.

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

The unstretched nonwoven fabric was placed on the unstretched film, supplied to a heating roll, and thermocompressed at a roll temperature of 80 ° C. The laminated sheet thus obtained was stretched 4.0 times in the length direction by a heating roll at 90 ° C., then sent to a tenter type horizontal stretching machine, stretched 4.0 times in the width direction at 95 ° C., and further stretched in the tenter. At 120 ° C. for 10 seconds to produce a heat-sensitive stencil sheet. On the film surface of the base paper, an aqueous emulsion of silicone oil (SH-200 manufactured by Dow Corning Toray Silicone Co., Ltd.) was weighed at 0.1 g / m ² after drying using a gravure coater at the entrance of the tenter. Applied. The 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 was found to have a network formed by fusion of fibers.

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

Example 2 Copolymer polyethylene-2,6-naphthalate containing 5% by mole 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 copolymerized polyester resin raw material (Tm = 250 ° C.). The obtained raw material was dried under reduced pressure at 170 ° C. for 3 hours using a rotary dryer, extruded at a T-die die 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.

The unstretched nonwoven fabric of Example 1 was overlaid on the unstretched film, and supplied to a heating roll.
Thermocompression bonding was performed at ℃. The laminated sheet thus obtained was put into 135
After stretching 4.0 times in the length direction with a heating roll at a temperature of 135 ° C., it was sent to a tenter-type transverse stretching machine, and then stretched at 135 ° C. in the width direction.
It was stretched 0-fold and heat-treated in a tenter at 150 ° C. for 10 seconds to prepare a heat-sensitive stencil sheet. Silicone oil (SH-20 manufactured by Dow Corning Toray Silicone Co., Ltd.) is provided at the entrance of the tenter on the film surface of the base paper.
The aqueous emulsion of 0) was applied using a gravure coater at a weight after drying of 0.1 g / m ² . The 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 summarized in Table 1, when the printability was evaluated using the finally obtained base paper, the base paper had high printing durability and was good.

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

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

The unstretched nonwoven fabric was placed on the unstretched film, supplied to a heating roll, and thermocompressed 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 sent to a tenter type horizontal stretching machine, stretched 4.0 times in the width direction at 135 ° C., and further expanded in the tenter. At 150 ° C. for 10 seconds to produce a heat-sensitive stencil sheet. At the entrance of the tenter, a silicone oil (Toray
An aqueous emulsion of Dow Corning Silicone Co., Ltd. (SH-200) was applied using a gravure coater at a weight of 0.1 g / m ² after drying. The 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 was found to have a network formed by fusion of fibers.

[Evaluation Results] As summarized in Table 1, when the printability was evaluated using the finally obtained base paper, 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 in the production of the nonwoven fabric, the discharge rate was changed and the average fiber diameter of the nonwoven fabric was changed as shown in Table 1.

[Evaluation Results] As summarized in Table 1, the base paper of the present invention has good printing durability, whereas if the average fiber diameter is out of the range of the present invention, the sensitivity may decrease, Poor printing durability.

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

[0075]

[Table 1]

[0076]

According to the present invention, the above-mentioned structure is provided.
Since a support having a uniform aperture form can be formed, a base paper having a stable strength can be obtained, and a printed matter obtained by stencil printing using the base paper has high image quality and print sharpness. And excellent printing durability.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-6-305273 (JP, A) JP-A-2-107488 (JP, A) JP-A-62-116194 (JP, A) JP-A-1- 168494 (JP, A) JP-A-4-100914 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B41N 1/24 102

Claims (2)

(57) [Claims] The main repeating unit is ethylene-2,6.
A film composed of a polymer that is naphthalate and a nonwoven fabric composed of a polymer whose main repeating unit is ethylene-2,6-naphthalate are bonded to each other without using an adhesive, and constitute a nonwoven fabric. A heat-sensitive stencil sheet having an average fiber diameter of 1 to 15 μm. 2. The tensile modulus in the longitudinal direction is 0.2 kg / c.
2. The heat-sensitive stencil sheet according to claim 1, which is at least m.