JPH10324074A - Thermosensitive stencil printing base paper - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a base paper from developing wrinkles at its installation to a place cylinder by a method wherein the maximum bending torque in either longitudinal or lateral direction measured with a pure bending tester of the base paper is set to be larger than a specified value. SOLUTION: An undrawn non-woven fabric is made of polyethylene terephthalate stock. An undrawn film is produced by extruding copolymer polyester resin stock from an extruder. The undrawn non-woven fabric, on which the undrawn film is put, is fed to a longitudinal extruder so as to paste the undrawn non-woven fabric to the undrawn film in order to orient and cool the undrawn film pasted with the undrawn non-woven fabric between orientation rolls and then feed and stretch them in a tenter type lateral stretcher in order to heat-treat them in a heat-treating zone for taking up in a roll. By applying a wax-based releasant of the film surface, a thermosensitive stencil printing base paper is produced so that the paper has the maximum bending torque in either longitudinal or lateral direction measured with a pure bending tester of 0.5 Ncm/cm or higher. As a result, the base paper can be prevented from developing wirinkles at its installation to a plate cylinder.

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 perforated by a thermal head or the like, and more particularly to a heat-sensitive stencil sheet which is free from wrinkles at the time of printing. .

[0002]

2. Description of the Related Art Conventionally, as heat-sensitive stencil base paper,
Polyester film, vinylidene chloride film, etc. thermoplastic resin film, natural fiber, synthetic fiber or synthetic fiber or a thin paper, nonwoven fabric, gauze, etc. made by mixing these are bonded with an adhesive. Structures are known (see, for example,
2513, JP-A-57-182495, etc.).

In recent years, heat-sensitive stencil printing machines have been improved to meet the demands for high-definition printing and high-speed plate making, such as increasing the density of thermal elements of a thermal head and reducing plate making energy. Highly sensitive base paper is required.

In order to improve the sensitivity, a film having a specified thickness (Japanese Patent Publication No. 3-65280) and a film having specified thermal characteristics of a biaxially stretched polyester film (Japanese Patent Application Laid-Open No. 62-282988). Japanese Patent Application Laid-Open No. Sho 62-149496), a film having a specified heat shrink characteristic (Japanese Patent Application Laid-Open No. 62-282983, Japanese Patent Application Laid-Open No. 63-160895), and the like. Although heat-sensitive stencil printing papers using these films have improved sensitivity, there is a problem that the paper is greatly curled during transportation or plate-making, although the base paper is greatly curled.

Japanese Patent Application Laid-Open No. Hei 6-305273 discloses that a base paper is obtained by co-drawing an undrawn polyester film and an undrawn polyester fiber. The base paper does not require the use of an adhesive and has high sensitivity, but it has been found that wrinkles are liable to occur during printing.

Further, a nonwoven fabric having a specified basis weight, thickness and flexural rigidity (Japanese Patent Laid-Open No. 3-76894) has been proposed in order to prevent wrinkles and wrinkles during lamination of a film and a nonwoven fabric. The base paper used as the support was still insufficient for preventing wrinkles during plate-making.

[0007]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a base paper which is free from wrinkles at the time of plate formation, which is insufficient with conventional base paper.

[0008]

Means for Solving the Problems In view of the above problems, the present inventors have conducted intensive studies and as a result, found that the above problems can be solved by setting the maximum bending torque of the base paper in a specific range. Was.

That is, the present invention relates to a heat-sensitive stencil printing paper comprising a thermoplastic resin film and a porous support having ink-permeability. A heat-sensitive stencil sheet having a maximum bending torque of 0.5 Ncm / cm or more.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, when a base paper is measured with a KES type pure bending tester at a clamping interval of 1 cm, the maximum bending torque of the base paper in either the vertical direction or the horizontal direction is 0.5 Ncm / cm or more. It is important. Preferably at least 1.0 Ncm / cm, more preferably 1.5 Ncm / cm
Ncm / cm or more. If the maximum bending torque in either the vertical or horizontal direction is less than 0.5 Ncm / cm, wrinkles are likely to occur at the time of printing, which is not preferable. on the other hand,
The upper limit of the maximum bending torque is about 4 Ncm / c as long as the perforation sensitivity of the film and the ink permeability of the support are not impaired.
m.

The maximum bending torque referred to in the present invention is KES
Type pure bending tester (Kato-Tech Corporation KES-FB2)
Using a sample length 20 cm, clamp width 1 cm, in a range of curvature -2.5cm ^-1 ~ + 2.5cm ^-1, performs pure bending test of constant velocity curvature deformation rate 0.5 cm ^-1 / s , Means the maximum value of the bending moment in the obtained bending moment-curvature diagram.

The term "vertical direction of the base paper" used in the present invention refers to
The longitudinal direction (running direction) of the base paper wound in a roll shape is referred to, and the horizontal direction is the width direction of the base paper.

[0013] KES formula bending rigidity B value of the base paper of the present invention is preferably a 0.1~2Ncm ² / cm, more preferably 0.2~2Ncm ² / cm, particularly preferably 0.4～2Ncm ² / Cm. KES type bending rigidity B
When the value is 0.1 to ² Ncm ² / cm, the traveling in the printing press is good.

When the thermoplastic resin film of the present invention is a polyester film, its thickness is preferably 0.5 to 5 μm, more preferably 0.5 to 3 μm, and particularly preferably 0.5 to 2.5 μm. When the thickness is 5 μm or less, the piercing property does not decrease, and when the thickness is 0.1 μm or more, the film forming stability is good.

When the thermoplastic resin film of the present invention is a polyester film, its orientation parameter is 3-10.
It is more preferably 3.5 to 8, particularly preferably 4 to 7. If the orientation parameter is 3 to 10,
The film can be sufficiently shrunk by the heat perforation of the thermal head, and a base paper having high perforation sensitivity can be obtained.

The orientation parameter in the present invention was determined by laser Raman spectroscopy. The film is embedded in PMMA resin and wet polished to form a cross section perpendicular to the length or width direction of the film, for example, Jobin Yvo.
n / “Ramanor” U-1000 manufactured by Atago Bussan Co., Ltd.
I (light source: GLG3300 Ar ⁺ laser 514.5 nm, manufactured by NEC Corporation, microscope: Olympus Optical Co., Ltd.)
Using a BH-2 type objective lens × 100) and irradiating a laser beam perpendicularly to the cross section to obtain a Raman spectrum of the laser beam polarized in the plane direction of the film and the laser beam polarized in the thickness direction of the film. 1615cm ^-1
When the peak intensities of the bands are I and _ND , respectively,
The ratio I / _IND was used as a film orientation parameter.

When the thermoplastic resin film of the present invention is a polyester film, its melting point is preferably 230 ° C. or lower, more preferably 220 ° C. or lower. When two or more peaks of the melting point are measured by a differential scanning calorimeter, at least one peak temperature is 230 ° C.
It is preferred that: When the melting point is 230 ° C. or less, the heat perforation property of the film becomes good.

The melting point of the thermoplastic resin film of the present invention is preferably lower than that of the porous support, more preferably the difference is 5 ° C. or more, particularly preferably 10 ° C. or more. When the melting point of the film is lower than the melting point of the support, the support is preferably not thermally deformed by the heat of the thermal head during plate making.

When the thermoplastic resin film of the present invention is a polyester film, its crystal melting energy (ΔHu) is preferably 10 to 50 J / g, more preferably 15 to 40 J / g. ΔHu is 10 to 50 J /
With g, the perforated shape of the film becomes uniform and stable.

The basis weight of the porous support of the present invention is preferably ² to ²⁰ g / m ² , more preferably 2 to 16 g / m 2.
g / m ^2, particularly preferably 3~14g / m ^2. If the basis weight is ² to 20 g / m ² , the balance between the ink retention and the ink permeability will be excellent.

When the porous support of the present invention is made of polyester fiber, the fiber diameter is preferably 1 to 20.
μm, more preferably 2 to 15 μm, particularly preferably 3 μm
１２12 μm. When the fiber diameter is 1 μm or more, sufficient strength as a support is obtained, and when the fiber diameter is 20 μm or less, the flatness of the film is good.

When the porous support of the present invention is a polyester fiber, its crystallinity is preferably at least 10%, more preferably at least 15%, particularly preferably at least 20%.
That is all. When the crystallinity is 10% or more, sufficient heat resistance as a support can be obtained.

The base paper of the present invention has a total base paper thickness of preferably 30 to 120 μm, more preferably 30 to 1 μm.
00 μm, particularly preferably 30 to 80 μm. When the thickness of the entire base paper is 30 μm or more, the ink is not faded even when a large number of sheets are printed, and when the thickness is 120 μm or less, no set-off occurs.

The thermoplastic resin film in the present invention is not particularly limited as long as it has a heat-perforating property. Examples thereof include polyester, polyamide, polypropylene, polyethylene, polyvinyl chloride, polyvinylidene chloride films and copolymer films thereof. Is preferred. A polyester film is more preferable in terms of perforation sensitivity.

In the present invention, the polyester used for the polyester film has an aromatic dicarboxylic acid, an aliphatic dicarboxylic acid or an alicyclic dicarboxylic acid and a diol as main components. Here, as the aromatic dicarboxylic acid component, for example, terephthalic acid, isophthalic acid, phthalic acid, 1,4-naphthalenedicarboxylic acid, 1,1,
5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 4,4'-diphenyldicarboxylic acid, 4,
4′-diphenyl ether dicarboxylic acid, 4,4′-diphenyl sulfone dicarboxylic acid and the like can be used,
Among them, terephthalic acid, isophthalic acid, 2,6
-Naphthalenedicarboxylic acid or the like can be used. Examples of the aliphatic dicarboxylic acid component include succinic acid, adipic acid, suberic acid, sebacic acid, dodecanedioic acid,
Eicosandioic acid, dimer acid and the like can be used. As the alicyclic dicarboxylic acid component, for example, 1,
4-cyclohexanedicarboxylic acid or the like can be used. One of these acid components may be used alone, or two or more thereof may be used in combination. Further, an oxyacid such as hydroxybenzoic acid may be partially copolymerized. Examples of the diol component include ethylene glycol, 1,2-propanediol, 1,3-propanediol, neopentyl glycol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,2-cyclohexanedimethanol,
1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, diethylene glycol, triethylene glycol, polyalkylene glycol, 2,2
-Bis (4-hydroxyethoxyphenyl) propane or the like can be used. Among them, ethylene glycol,
1,4-butanediol, 1,6-hexanediol,
1,4-Cyclohexanedimethanol is preferably used. These diol components may be used alone,
Two or more kinds may be used in combination.

The polyester used in the polyester film of the present invention is preferably polyethylene terephthalate, a copolymer of ethylene terephthalate and ethylene isophthalate, polyethylene-2,6-naphthalate, polybutylene terephthalate, polyhexamethylene terephthalate, polyhexamethylene. -2,6-naphthalate, copolymer of butylene terephthalate and ethylene terephthalate, copolymer of butylene terephthalate and hexamethylene terephthalate, copolymer of hexamethylene terephthalate and 1,4-cyclohexane dimethylene terephthalate, ethylene terephthalate And a blend of ethylene-2,6-naphthalate and a blend thereof. Particularly preferred for improving the perforation sensitivity, a copolymer of ethylene terephthalate and ethylene isophthalate, polyhexamethylene terephthalate, hexamethylene terephthalate and 1,4-cyclohexane dimethylene terephthalate,
A copolymer of ethylene terephthalate and ethylene-2,6-naphthalate can be used.

The polyester film of the present invention may optionally contain a flame retardant, an antioxidant, an ultraviolet absorber, a pigment, a dye, an antifoaming agent such as polysiloxane, and the like. Further, the following lubricity 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, organic particles containing acrylic acid, styrene, etc., a polyester polymerization reaction There is a method using so-called internal particles in which a catalyst or the like to be added sometimes is precipitated.

The ink-permeable porous support of the present invention refers to a nonwoven fabric which allows the passage of printing ink and does not substantially undergo thermal deformation under heating conditions under which a film is perforated.
Woven fabric or other porous bodies can be used. The porous support is preferably a nonwoven fabric, and a polyester nonwoven fabric made of polyester fibers is particularly preferred.

In the present invention, the polyester constituting the non-woven fabric is mainly composed of an aromatic dicarboxylic acid, an aliphatic dicarboxylic acid or an alicyclic dicarboxylic acid and a diol, as in the case of the thermoplastic resin film. Preferably, polyethylene terephthalate, polyethylene-2,6-naphthalate, poly-1,4-cyclohexane dimethylene terephthalate, a copolymer of ethylene terephthalate and ethylene isophthalate, and the like can be used. Particularly preferred is polyethylene terephthalate, polyethylene-
2,6-naphthalate.

The polyester fiber preferably used in the present invention may contain, if necessary, an organic lubricant such as a flame retardant, a heat stabilizer, an antioxidant, an ultraviolet absorber, an antistatic agent, a pigment, a dye, a fatty acid ester, or a wax, or a polyester. An antifoaming agent such as siloxane can be blended. Further, the surface of the fiber may be subjected to a chemical treatment such as an acid or an alkali, a corona treatment, a low-temperature plasma treatment or the like, if necessary, in order to impart affinity with the ink.

Next, a method for producing a heat-sensitive stencil sheet of the present invention will be described.

The polyester preferably used in the present invention can be produced by the following method. For example, a method in which an acid component is directly esterified with a diol component, and then the product of this reaction is heated under reduced pressure to remove the excess diol component and polycondensate to produce a dialkyl acid. There is a method of using an ester, performing a transesterification reaction between the ester and a diol component, and then performing polycondensation in the same manner as described above. At this time, if necessary, a metal compound can be used as a reaction catalyst, and a phosphorus compound or the like can be used as a heat stabilizer.

The polyester film preferably used as the thermoplastic resin film of the present invention can be produced by biaxially stretching an unstretched film extruded onto a cooling drum with a T-die.

The heat-sensitive stencil sheet of the present invention can be produced by bonding a thermoplastic resin film and a porous support with an adhesive under conditions that do not hinder the perforation characteristics of the film. When an adhesive is used, the adhesive is dissolved in a solvent and laminated, or an adhesive such as a hot melt type, an emulsion latex type, or a UV curable type is applied and bonded. The amount of the adhesive used is 0.1 to 5 g / m
² is preferred. The adhesive may be applied to the film surface, the porous support surface, or both.

The heat-sensitive stencil printing paper of the present invention can be produced by a method of thermally bonding a thermoplastic resin film and a porous support without using an adhesive. In the case of thermal bonding, a method using a heating roll is preferable. Thermal bonding conditions can be appropriately selected depending on the type and thickness of the thermoplastic resin film to be used.

The method for adhering the thermoplastic resin film and the porous support without using an adhesive is not particularly limited. However, the unstretched polyester film and the porous support made of unstretched polyester fiber are bonded by heat. It is preferably achieved by co-stretching both at the same time.

In order to thermally bond the unstretched polyester film and the support made of unstretched polyester fiber,
It is preferable that the unstretched polyester film and the support made of unstretched polyester fiber are pressed while heating in a stacked state, and the method is not particularly limited.
Heat bonding with a heating roll is particularly preferred. The heat bonding temperature is preferably around the glass transition point (Tg) of the polyester film, and particularly preferably in the range of Tg-10 ° C to Tg + 30 ° C. The pressure at the time of thermal bonding is 0.1 to 10 as a roll linear pressure.
It is preferable to carry out in the range of 0 N / cm.

The method of co-stretching the heat-bonded unstretched polyester film and unstretched polyester fiber is not particularly limited, and may be either uniaxial stretching or biaxial stretching. More preferred. The biaxial stretching may be either a sequential biaxial stretching method or a simultaneous biaxial stretching method, but the sequential biaxial stretching is particularly preferred. In the case of sequential biaxial stretching, it is general that transverse stretching is generally performed by a tenter after longitudinal stretching by a group of heating rolls, but may be reversed. As the material of the heating roll, metal, "Teflon", ceramic, silicon rubber and the like are preferably used. The material of the nip roll is particularly preferably silicon rubber. The nip pressure during stretching is 0.1 to 10 as a roll linear pressure.
It is preferable to carry out in the range of 0 N / cm. Stretching temperature is 50
C. to 150.degree. C., more preferably 60.degree.
It is preferable to carry out in the range of 130 ° C. Further, in order to uniformly perform heating during stretching, only the polyester fiber of the support may be preheated alone and then supplied to the stretching roll. Further, in order to uniformly stretch the polyester film and the polyester fiber of the support, the heat-bonded film and the support may be heated by an infrared heater or the like immediately before stretching.

The stretching ratio is not particularly limited, but it is usually preferably 2 to 8 times each in the vertical and horizontal directions, more preferably 3 to 8 times.
Double is appropriate. After biaxial stretching, the film may be stretched longitudinally or horizontally, or vertically and horizontally again.

The unstretched polyester film can be produced, for example, by extruding a polymer onto a cooling 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. At this time, a so-called electrostatic application casting method in which static electricity is applied to the polymer to increase the adhesion to the drum may be used.

The intrinsic viscosity of the polyester used for the film is preferably 0.5 or more, more preferably 0.6 or more, and further preferably 0.65 or more. When the intrinsic viscosity is 0.5 or more, the film-forming stability is good, and particularly, casting of a thin film becomes easy.

The porous support made of the unstretched polyester fiber can be manufactured into a nonwoven fabric by a direct melt spinning method such as a melt blow method or a spun bond method.

For example, in the melt blow spinning method, when a molten polymer is discharged from a die, hot air is blown from the periphery of the die, the discharged polymer is made finer, and then the net conveyor is arranged at an appropriate position. It is collected by spraying on the top and manufactured as a non-woven web. Since the web is sucked together with the hot air by the suction device provided on the net conveyor, the fibers are collected before the fibers are completely solidified. That is, the fibers 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 between the fibers can be adjusted. Also, by appropriately adjusting the amount of discharged polymer, the temperature of hot air, the flow rate of hot air, the conveyor speed, and the like, the thickness and basis weight of the fibers can be adjusted. The melt-blow spun fiber is made finer by the pressure of hot air and solidified in a non-oriented or extremely low-oriented so-called undrawn state. The polymer discharged from the die is rapidly cooled from a molten state to an atmosphere at room temperature, so that it solidifies in a low-crystalline state close to amorphous.

Similarly, in the spun bond method, the polymer discharged from the die is pulled by an air ejector, and the obtained filaments are caused to collide with a collision plate to spread the fibers.
It is manufactured by collecting it on a conveyor. The weight of the nonwoven fabric can be arbitrarily set by appropriately setting the polymer discharge amount and the conveyor speed. By appropriately adjusting the pressure and flow rate of the ejector, the thickness of the fiber and the molecular orientation can be adjusted. By reducing the spinning speed by reducing the pressure and the flow rate, a nonwoven fabric having a low degree of molecular orientation and close to an undrawn state can be obtained. Further, by adjusting the cooling rate of the discharged polymer, a non-woven fabric having low crystallinity can be obtained.

In the case of production by the spunbond method, the unstretched polyester nonwoven fabric used for obtaining the base paper of the present invention is preferably spun at a spinning speed of 1500 m / min or less, more preferably 1000 m / min or less, particularly preferably 1000 m / min or less. Preferably it is 800 m / min or less.

The crystallinity of the unstretched polyester nonwoven fabric preferably used in the present invention is preferably 20% or less, more preferably 10% or less, and particularly preferably 5% or less.

The unstretched polyester nonwoven fabric preferably used in the present invention is most preferably unstretched. However, even if it is stretched, it preferably has a low magnification and a low degree of orientation, and is referred to as birefringence (Δn). , 0.03 or less, more preferably 0.02 or less, particularly preferably 0.01 or less. Here, birefringence refers to the use of a sodium lamp as a light source and
-It is a value calculated by obtaining retardation by the Berk convention method under immersion in promnaphthalene.

The intrinsic viscosity of the polymer used for the polyester nonwoven fabric is preferably 0.35 or more, more preferably 0.4 or more, and particularly preferably 0.45 or more. If the intrinsic viscosity is 0.35 or more, a fiber having sufficient strength can be obtained.

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 depending on the type of the polymer for a film to be used, but is preferably from 80 to 200 ° C, more preferably from 80 to 170 ° C, further more preferably from 90 to 150 ° C, and the time is from 0.1 to 150 ° C. About 5 to 60 seconds is appropriate.

Further, the base paper obtained by the heat treatment may be once cooled to about room temperature and then aged at a relatively low temperature of 40 to 90 ° C. for about 5 minutes to 1 week.
The use of such aging is particularly preferable because curling during storage of the base paper or in the printing press can be suppressed.

The method for setting the maximum bending torque of the base paper within the range of the present invention is not particularly limited. In particular, when the porous support is a polyester nonwoven fabric and is bonded to a polyester film without an adhesive, This can be achieved by appropriately adjusting not only the fiber diameter and the basis weight of the unstretched nonwoven fabric to be used, but also the state of adhesion between the fibers, the magnification of co-stretching, the stretching temperature, the heat treatment temperature, and the like. In general, the stronger the adhesion between fibers, the greater the co-drawing ratio,
Further, the higher the stretching temperature, the larger the maximum bending torque tends to be. As a method of strengthening the adhesion between fibers,
In the spinning stage of the undrawn nonwoven fabric, it can be achieved by adjusting the temperature of the hot air or the atmosphere to increase the temperature of the fiber collecting surface, or by adjusting the suction pressure of the suction. It is also effective to heat and press the unstretched nonwoven fabric once collected by a calender roll or the like, and then to co-stretch the unstretched film. further,
The co-stretched film and the support may be calendered. A part of the support may be impregnated with a resin such as urethane.

The base paper of the present invention is used to prevent fusing at the time of perforation on one side of the film to be in contact with the thermal head.
Silicone oil, silicone resin, fluorine resin,
It is preferable to provide a thin layer comprising a surfactant, an antistatic agent, a heat-resistant agent, an antioxidant, organic particles, inorganic particles, a pigment, a dispersing agent, a preservative, an antifoaming agent, and the like. The thickness of the thin layer for preventing fusion is preferably 0.005 μm or more and 0.4 μm or less,
More preferably, it is 0.01 μm or more and 0.4 μm or less.

When a thin layer for preventing fusion is provided on the base paper of the present invention, it is preferable to apply the coating solution in the form of a coating solution dissolved, emulsified or suspended in water, and then remove the water by drying or the like. . The coating may be performed at any stage before or after the stretching of the film.

In order to make the effect of the present invention more remarkable, it is necessary to apply the film before the transverse stretching in the case of sequential biaxial stretching in which the film is stretched horizontally after the longitudinal stretching, and before the stretching in the case of simultaneous biaxial stretching. Is particularly preferred. The application method is not particularly limited, but a roll coater, a gravure coater, a reverse coater,
It is preferable to apply by using a bar coater or the like.

Before providing the thin layer for preventing fusion, if necessary, an activation treatment such as a corona discharge treatment may be applied to the coated surface in air or other various atmospheres.

[0056]

[Method of measuring characteristics]

(1) Maximum bending torque (Ncm / cm) KES type pure bending tester (KES-
Using FB2), a sample having a length of 20 cm is gripped with a clamp width of 1 cm, and the curvature K is from −2.5 cm ⁻¹ to +2.5 c.
A pure bending test with constant velocity curvature was performed in the range of m ^-1 at a deformation rate of 0.5 cm ^-1 / s, and the obtained bending moment (unit:
Ncm / cm) and the curvature (unit: cm ⁻¹ ), the maximum value of the bending moment was determined as the maximum bending torque. The measurement was performed in the vertical and horizontal directions of the base paper.
The measurement was performed at each of five points, and the average value was obtained.

(2) Melting point (° C.) Differential scanning calorimeter RDC220 manufactured by Seiko Instruments Inc.
Using a mold, a 5 mg sample was collected, and the temperature was
It was determined from the peak temperature of the endothermic curve when the temperature was raised at a rate of ° C./min.

(3) Film Thickness A section of the base paper was cut out, and the section was observed by a scanning electron microscope at a magnification of 1,000 to 10,000 times.

(4) Overall thickness of base paper A dial thickness gauge (“PEACOC” manufactured by Ozaki Seisakusho Co., Ltd.)
K ″ H type).

(5) Crystal melting energy (ΔHu) Differential scanning calorimeter RDC220 manufactured by Seiko Denshi Kogyo KK
It is determined from the area 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. I under the same DSC conditions
n (indium) was measured, and this area (b) was determined to be 28.5.
It is calculated by the following equation as J / g.

28.5 × a / b = ΔHu (J / g)

(6) Weight of Support (g / m ² ) A piece of base paper (20 cm × 20 cm) was taken and its weight was measured. The weight of the film was reduced and converted to the weight per m ² . The weight of the film was determined by multiplying the film thickness by the density.

(7) Evaluation of wrinkles The prepared base paper was supplied to a printing machine “Risograph” GR275 manufactured by Riso Kagaku Kogyo Co., Ltd., and a plate making / printing test was performed 100 times using all B4 size solid originals. The base paper of the plate cylinder was visually observed and judged as follows.

原: no wrinkles were formed on the base paper:: one or two times wrinkles were generated. ○: 3 to 5 times of wrinkles were generated. ◎, △, and Δ are for practical use.

[0065]

The present invention will be described in more detail with reference to the following examples.

Example 1 Polyethylene terephthalate raw material ([η] = 0.50,
Tm = 255 ° C.), pore diameter 0.3 mm, number of holes 100
The polymer discharge amount was 35 g / min, melt temperature was 290 ° C., hot air temperature was 295 ° C., hot air flow rate was 400 Nm ³ / h, collection surface temperature was 90 ° C., fiber diameter was 8.3 μm, and the basis weight was 120 g / min. An unstretched nonwoven fabric of m ² was produced.

Then, a copolymerized polyester resin raw material ([η] = 0.70, Tm = 21) composed of 85 mol% of ethylene terephthalate and 15 mol% of ethylene isophthalate was used.
7 ° C.) using an extruder having a screw diameter of 90 mm,
It was extruded at a die temperature of 270 ° C. and cast on a cooling drum having a diameter of 500 mm to produce an unstretched film having a thickness of 20 μm.

The unstretched nonwoven fabric is superimposed on the unstretched film, supplied to a longitudinal stretching machine, passed through a group of preheating rolls, and bonded to the unstretched film. It was stretched 5 times and cooled to room temperature. At this time, the temperature of the film surface was measured between the stretching rolls using a non-contact thermometer, and the temperatures of the preheating roll and the stretching roll were adjusted so that the film surface temperature became 95 ° C. The nip linear pressure of the stretching roll was 5 N / cm.

Then, it is sent to a tenter type horizontal stretching machine,
The film was stretched 3.8 times in the width direction at a preheating temperature of 90 ° C. and a stretching temperature of 95 ° C., heat-treated at a temperature of 150 ° C. in a heat treatment zone in a tenter, and wound into a roll.

Next, a wax-based release agent was applied to the film surface to prepare a heat-sensitive stencil sheet. The thickness of the obtained base paper is 90 μm, the fiber diameter of the support is 4.3 μm, and the basis weight is 1
0.5 g / m ² , and the thickness of the film was 1.5 μm.

The maximum bending torque of the base paper by the KES type pure bending tester was vertical / horizontal = 0.56 / 0.52 Ncm /
cm.

Example 2 In Example 1, the fiber diameter was changed by changing the hot air flow rate.
A heat-sensitive stencil sheet was prepared in the same manner as in Example 1, except that an unstretched nonwoven fabric having a thickness of 5 μm and a basis weight of 120 g / m ² was prepared. The thickness of the obtained base paper was 100 μm, the fiber diameter of the support was 5.5 μm, the basis weight was 10.5 g / m ² , and the thickness of the film was 1.5 μm.

The maximum bending torque of the base paper by the KES type pure bending tester was vertical / horizontal = 0.87 / 0.80 Ncm /
cm.

Comparative Example 1 In Example 1, the hot air flow rate was changed, and the fiber diameter was 4.5.
A heat-sensitive stencil sheet was prepared in the same manner as in Example 1, except that an unstretched nonwoven fabric having a thickness of 120 μm and a mass of 120 g / m ² was prepared. The thickness of the obtained base paper was 80 μm, the fiber diameter of the support was 2.1 μm, the basis weight was 10.5 g / m ² , and the thickness of the film was 1.5 μm.

The maximum bending torque of the base paper by the KES type pure bending tester was vertical / horizontal = 0.45 / 0.42 Ncm /
cm.

Example 3 A heat sensitive stencil sheet was prepared in the same manner as in Example 1 except that the conveyor speed was changed to produce an unstretched nonwoven fabric having a fiber diameter of 8.3 μm and a basis weight of 140 g / m ^2. Was prepared. The thickness of the obtained base paper was 110 μm, the fiber diameter of the support was 4.3 μm, the basis weight was 12.5 g / m ² , and the thickness of the film was 1.5 μm.

The maximum bending torque of the base paper by a KES type pure bending tester was vertical / horizontal = 1.05 / 1.12 Ncm /
cm.

Comparative Example 2 A heat-sensitive stencil sheet was prepared in the same manner as in Example 1 except that the conveyor speed was changed to produce an unstretched nonwoven fabric having a fiber diameter of 8.3 μm and a basis weight of 80 g / m ^2. Was prepared. The thickness of the obtained base paper was 60 μm, the fiber diameter of the support was 4.3 μm, the basis weight was 6.2 g / m ² , and the thickness of the film was 1.5 μm.

The maximum bending torque of the base paper by the KES type pure bending tester was vertical / horizontal = 0.39 / 0.35 Ncm /
cm.

Example 4 In Example 1, the temperature of the collecting surface was changed to 100 ° C.
A heat-sensitive stencil sheet was prepared in the same manner as in Example 1 except that an unstretched nonwoven fabric having a fiber diameter of 8.3 μm and a basis weight of 120 g / m ² was prepared. The thickness of the obtained base paper was 80 μm, the fiber diameter of the support was 4.3 μm, the basis weight was 10.5 g / m ² , and the thickness of the film was 1.5 μm.

The maximum bending torque of the base paper by the KES type pure bending tester was vertical / horizontal = 1.28 / 1.30 Ncm /
cm.

Example 5 In Example 1, the temperature of the collecting surface was changed to 120 ° C.
A heat-sensitive stencil sheet was prepared in the same manner as in Example 1 except that an unstretched nonwoven fabric having a fiber diameter of 8.3 μm and a basis weight of 120 g / m ² was prepared. The thickness of the obtained base paper was 70 μm, the fiber diameter of the support was 4.3 μm, the basis weight was 10.5 g / m ² , and the thickness of the film was 1.5 μm.

The maximum bending torque of the base paper by the KES type pure bending tester was vertical / horizontal = 0.92 / 0.88 Ncm /
cm.

Comparative Example 3 An unstretched nonwoven fabric having a fiber diameter of 8.3 μm and a basis weight of 120 g / m ² was prepared in the same manner as in Example 1 except that the collecting surface temperature was changed to 80 ° C. To produce a heat sensitive stencil sheet. The thickness of the obtained base paper was 125 μm, the fiber diameter of the support was 4.3 μm, the basis weight was 10.5 g / m ² , and the thickness of the film was 1.5 μm.

The maximum bending torque of the base paper by the KES type pure bending tester was vertical / horizontal = 0.40 / 0.38 Ncm /
cm.

Example 6 In Example 4, an unstretched non-woven fabric having a basis weight of 140 g / m ² was prepared, and the unstretched non-woven fabric was calendered using a calender roll composed of a metal roll and a silicone rubber roll. At 70 ° C. and a roll linear pressure of 5 N / cm to carry out calendering. A heat-sensitive stencil sheet was prepared in the same manner as in Example 1 using this nonwoven fabric. The thickness of the obtained base paper is 60 μm, the fiber diameter of the support is 4.3 μm,
The basis weight is 12.5 g / m ² , and the thickness of the film is 1.5 μm
Met.

The maximum bending torque of the base paper by the KES type pure bending tester was vertical / horizontal = 1.61 / 1.58 Ncm /.
cm.

Example 7 A heat-sensitive stencil sheet was prepared in the same manner as in Example 5, except that the calendering temperature was 80 ° C. and the roll linear pressure was 10 N / cm. The thickness of the obtained base paper is 50
μm, the fiber diameter of the support is 4.3 μm, and the basis weight is 12.5 g.
/ M ² film thickness was 1.5 μm.

The maximum bending torque of the base paper by the KES type pure bending tester was vertical / horizontal = 2.25 / 2.14 Ncm /
cm.

Comparative Example 4 A heat-sensitive stencil sheet was prepared in the same manner as in Example 5, except that the calendering temperature was 100 ° C. and the roll linear pressure was 10 N / cm. The thickness of the obtained base paper is 28 μm, the fiber diameter of the support is 4.3 μm, and the basis weight is 12.
5 g / m ² , and the thickness of the film was 1.5 μm.

The maximum bending torque of the base paper by the KES type pure bending tester was vertical / horizontal = 0.48 / 0.46 Ncm /
cm.

Example 8 The same procedure as in Example 1 was repeated, except that the obtained base paper was
% Urethane resin aqueous solution (Dainippon Ink Chemical Industry Co., Ltd.)
“HYDRAN” HW-350) is sprayed,
It was dried at room temperature for 10 hours. The thickness of the obtained base paper is 85
μm, the weight was 11.0 g / m ² , and the thickness of the film was 1.5 μm.

The maximum bending torque of the base paper by the KES type pure bending tester was vertical / horizontal = 1.58 / 1.52 Ncm /
cm.

[0094]

[Table 1] As can be seen from the results in Table 1, the heat-sensitive stencil base paper of the present invention in which the maximum bending torque in either the vertical or horizontal direction of the base paper is 0.5 Ncm / cm or more does not cause plate wrinkles and has a low printing quality. Excellent.

[0095]

The heat-sensitive stencil sheet of the present invention has a maximum bending torque of 0.5 Ncm / cm or more, so that wrinkles are generated when the prepressed stencil sheet is placed on the plate cylinder. Nothing. Therefore, a printed matter having high printing quality can be obtained by printing on the base paper of the present invention.

Claims (10)

[Claims] 1. A heat sensitive stencil printing paper comprising a thermoplastic resin film and an ink-permeable porous support, wherein the base paper has a maximum bending torque in either the vertical or horizontal direction by a KES type pure bending tester. But 0.5Ncm
/ Cm or more. 2. The base paper for heat-sensitive stencil printing according to claim 1, wherein the thermoplastic resin film and the porous support are joined without interposing an adhesive. 3. The base paper for heat-sensitive stencil printing according to claim 1, wherein the thermoplastic resin film is a polyester film. 4. A polyester film having a thickness of 0.1 to 0.1.
The base paper for heat-sensitive stencil printing according to any one of claims 1 to 3, wherein the base paper has a thickness of 5.0 µm. 5. The melting point of the polyester film is 230 ° C.
The heat-sensitive stencil sheet according to any one of claims 1 to 4, wherein: 6. The heat-sensitive stencil sheet according to claim 1, wherein the polyester film has a crystal melting energy of 10 to 50 J / g. 7. The base paper for heat-sensitive stencil printing according to claim 1, wherein the porous support comprises polyester fibers. 8. The porous support has a basis weight of ² to 20 g / m ^2.
The heat-sensitive stencil printing paper according to any one of claims 1 to 7, wherein 9. The polyester fiber having a diameter of 0.5 to 20.
The heat-sensitive stencil sheet according to any one of claims 1 to 8, wherein the stencil sheet has a thickness of μm. 10. The heat-sensitive stencil printing paper according to claim 1, wherein the thickness of the entire base paper is 30 to 120 μm.