JPH09315027A - Original paper for thermal stencil printing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To lower an energy supplying to a thermal head of a printing machine and to enhance higher fineness and shortening of a plate-making time by using this original paper, which has a small sensitiveness and a dispersion of the sensitiveness. SOLUTION: In an original paper for a thermal stencil printing which is formed by adhered a polyester film with a polyester nonwoven fabric without through a bonding agent, when an intrinsic viscosity and a melting point ( deg.C) of the film are devoted as [η] 1, Tm1, and an intrinsic viscosity and a melting point ( deg.C) of the nonwoven fabric are denoted as [η] 2, Tm 2, respectively the formulae: 0.5<=[η]1<=1.5, 140 deg.C<=Tm1<=240 deg.C, 0.3<=[η]2<=0.8, 180 deg.C<=Tm2<=280 deg.C, [η]1×Tm1/Tm2>[η] 2, and Tm1<Tm2-25 are satisfied.

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 printing base paper which is perforated by a thermal head or the like, and more particularly to a heat-sensitive stencil printing base paper having a high sensitivity and a small variation in the sensitivity.

[0002]

2. Description of the Related Art Conventionally, as heat-sensitive stencil printing base paper (hereinafter simply referred to as base paper), thermoplastic resin films such as polyester films and vinylidene chloride films have been used.
There is known a structure in which a porous support made of natural fiber, chemical fiber or synthetic fiber or a thin paper, nonwoven fabric, gauze or the like obtained by mixing them is bonded with an adhesive (for example, see Japanese Patent Application Laid-Open No. SHO 51-51). No. 2513, JP-A-57
182495).

[0003] However, the conventional base paper has the drawbacks that white spots occur in solid black portions and fine characters are blurred. It is considered that the cause of these poor print clarity is that the permeation of the ink is hindered by the adhesive bonding the film and the porous support.

Various proposals have been made so far in order to improve the drawbacks caused by these adhesives. For example, JP-A-58-147396, JP-A-4-23279
In Japanese Patent Laid-Open No. 0-44, a method of reducing the amount of adhesive used as much as possible and a method of using no adhesive are disclosed in
No. 212891 discloses a base paper in which synthetic fibers are sprinkled on one surface of a thermoplastic resin film and thermocompression bonded. However, it has been found that these methods have a problem in that the adhesive strength is insufficient, or that when sufficient adhesive strength is to be obtained, sufficient perforation does not occur and the print density does not increase.

Further, 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 has a sufficient adhesive force without using an adhesive, but there is a limit to the high sensitivity corresponding to the shortening of the plate making time and the miniaturization of the thermal head, and the sensitivity varies. I knew there was a problem.

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a base paper which has a high sensitivity and has a small variation which cannot be realized by the conventional base paper.

[0007]

[Means for Solving the Problems] In view of the above problems, the present inventors have made earnest studies and as a result, as a result of specifying the intrinsic viscosity and melting point of the film and the non-woven fabric in the base paper in which the film and the fiber are bonded without interposing an adhesive. The inventors have found that the above problem can be solved by setting the range to be, and have reached the present invention. That is, the present invention provides a heat-sensitive stencil printing base paper in which a polyester film and a polyester non-woven fabric are adhered to each other substantially without an adhesive, and the intrinsic viscosity and melting point (° C.) of the film are [η] 1 and Tm 1, respectively. The heat-sensitive stencil printing paper is characterized by satisfying the following formulas (1) to (6), where [η] 2 and Tm 2 are the intrinsic viscosity and the melting point (° C.) of the nonwoven fabric, respectively.

0.5 ≦ [η] 1 ≦ 1.5 (1) 140 ° C. ≦ Tm1 ≦ 240 ° C. (2) 0.3 ≦ [η] 2 ≦ 0.8 (3) 180 ° C. ≦ Tm2 ≦ 280 ° C. (4) [η] 1 × Tm1 / Tm2> [η] 2 (5) Tm1 <Tm2-25 (6)

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The polyesters used in the polyester film and the polyester nonwoven fabric in the present invention are mainly composed of aromatic dicarboxylic acid, aliphatic dicarboxylic acid or alicyclic dicarboxylic acid and diol. . Here, examples of the aromatic dicarboxylic acid component include terephthalic acid, isophthalic acid, phthalic acid, 1,4-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 4,4′- Diphenyldicarboxylic acid, 4,4'-diphenyletherdicarboxylic acid, 4,4'-diphenylsulfonedicarboxylic acid and the like can be used, and among them, terephthalic acid, isophthalic acid and 2,6-naphthalenedicarboxylic acid are preferably used. it can. 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, and among them, adipic acid and sebacic acid can be preferably used. Further, as the alicyclic dicarboxylic acid component, for example,
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, an oxy acid 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, and 1,4-cyclohexanedimethanol are preferably used. These diol components may be used alone or in combination of two or more.

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, polyhexahexene. Methylene-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 A copolymer of terephthalate and ethylene-2,6-naphthalate can be used. Particularly preferably in order to improve 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, or the like can be used.

The polyester used in the polyester nonwoven fabric of the present invention is preferably polyethylene terephthalate, polyethylene-2,6-naphthalate,
Poly-1,4-cyclohexane dimethylene terephthalate, a copolymer of ethylene terephthalate and ethylene isophthalate, or the like can be used. From the viewpoint of thermal dimensional stability during perforation, polyethylene terephthalate, polyethylene naphthalate and the like can be used particularly preferably.

The polyester in the present invention can be manufactured 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, as a reaction catalyst, an alkali metal, an alkaline earth metal,
Manganese, cobalt, zinc, antimony, germanium, titanium compounds and the like can also be used. Further, a phosphorus compound can be used as a heat stabilizer.

The polyester 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 slipperiness imparting method can be adopted. For example, clay, mica, titanium oxide,
Calcium carbonate, kaolin, talc, inorganic particles such as wet or dry silica, alumina, zirconia, acrylic acid, a method of blending organic particles having styrene or the like as a constituent component, depositing a catalyst or the like added during the polyester polymerization reaction, There are a so-called internal particle method and a method of applying a surfactant.

The polyester non-woven fabric constituting the base paper in the present invention is obtained by stretching the non-stretched non-oriented non-woven fabric obtained by a direct melt spinning method such as a melt blow method or a spun bond method using the above polyester. It is a thing.

In the melt-blowing method, the unstretched nonwoven fabric is produced by blowing hot air from the periphery of the die when the molten polyester polymer is ejected from the die, making the polymer extruded by the hot air fine, and then arranging it at an appropriate position. It is sprayed and collected on the above-mentioned net conveyor, and a web is formed to be manufactured. 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 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. Further, by appropriately adjusting the polymer discharge amount, hot air temperature, hot air flow rate, conveyor moving speed, etc., it is possible to arbitrarily set the fiber orientation of the unstretched nonwoven fabric, the web areal weight and the single yarn fiber diameter. The fiber spun by the melt blow method is finely pulverized by the pressure of hot air and solidified in a non-oriented or low-oriented state is particularly preferably used. The fibers constituting the undrawn nonwoven fabric are preferably substantially continuous. Further, the polymer discharged from the die is rapidly cooled from a molten state to a room temperature atmosphere, so that it is almost amorphous.
It can be solidified in a low crystalline 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, by appropriately adjusting the pressure and the flow rate of the ejector, the molecular orientation state of the filament can be arbitrarily adjusted.
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 having low crystallinity can be obtained. When produced by the spunbond method, the unstretched polyester nonwoven fabric used to obtain the base paper of the present invention is preferably spun at a spinning speed of 2500 m / min or less, more preferably 2000 m / min.
Min or less, particularly preferably 1500 m / min or less.

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

The unstretched polyester non-woven fabric used in the present invention is most preferably unstretched, but it is more preferable that the unstretched polyester nonwoven fabric has a low draw ratio even when stretched and has a low degree of orientation. Usually, the birefringence (Δn) is preferably 0.03 or less, more preferably 0.02 or less, and particularly preferably 0.01 or less.

The base paper of the present invention is preferably obtained by stacking an unstretched film and the above unstretched nonwoven fabric and biaxially stretching them. The method of forming an unstretched film using polyester and the method of biaxial stretching are based on the following methods. For example, an unstretched film can be produced by extruding polyester onto a cast drum by the 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 polyester film and the polyester non-woven fabric in the present invention are adhered to each other substantially without an adhesive. Most preferably, the adhesion is performed with an unstretched polyester film obtained by extrusion-casting the unstretched polyester nonwoven fabric described above, and in a stage before the longitudinal stretching step. Usually, the heat-bonding temperature is preferably between the glass transition temperature and the melting point of the polyester film, and more preferably between the glass transition temperature and the elevated temperature crystallization temperature.

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, stretching is generally performed in the longitudinal direction and then in the transverse direction, but may be performed in the opposite direction. The stretching temperature is preferably between the glass transition temperature of the polyester film and the elevated crystallization temperature. 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 preferably 2 to 8 times in length and width, and more preferably 3 to 8 times.
8 times is appropriate. After biaxial stretching, the film may be stretched longitudinally or horizontally, or vertically and horizontally again.

After that, the biaxially stretched film and the stretched material of the nonwoven fabric may be heat-treated. The heat treatment temperature is not particularly limited and may be appropriately determined depending on the type of the film polymer and the non-woven fabric polymer to be used.
A temperature of 0 to 200 ° C., preferably 80 to 170 ° C., more preferably 90 to 150 ° C., and a time of 0.5 to 60 seconds are suitable.

The base paper obtained by heat treatment is once cooled to about room temperature and then at a relatively low temperature of 40 to 90 ° C. for 5 minutes.
It can be aged for about a week to a minute. When such aging is 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 base paper of the present invention has the following formulas when the intrinsic viscosity and melting point (° C.) of the film are [η] 1 and Tm1, and the intrinsic viscosity and melting point (° C.) of the non-woven fabric are [η] 2 and Tm2, respectively. It satisfies (1) to (6).

0.5 ≦ [η] 1 ≦ 1.5 (1) 140 ° C. ≦ Tm1 ≦ 240 ° C. (2) 0.3 ≦ [η] 2 ≦ 0.8 (3) 180 ° C. ≦ Tm2 ≦ 280 ° C. (4) [η] 1 × Tm1 / Tm2> [η] 2 (5) Tm1 <Tm2-25 (6)

When [η] 1 <0.5, the film is easily broken and causes pinholes, and when [η] 1> 1.5, the uniformity of the film is deteriorated and the variation in sensitivity is increased. Not preferable. [Η] 1 preferably satisfies the following expression (7).

0.53 ≦ [η] 1 ≦ 1 (7)

If Tm1 <140 ° C., variations in sensitivity will increase due to curls during storage, and Tm1
When it is> 240 ° C, the sensitivity is lowered, which is not preferable.
Tm1 preferably satisfies the following expression (8).

150 ° C. ≦ Tm1 ≦ 230 ° C. (8)

On the other hand, if [η] 2 <0.3, the function as a support is deteriorated, and if [η] 2> 0.8, variations in sensitivity increase, which is not preferable. [Η] 2 preferably satisfies the following expression (9).

0.35 ≦ [η] 2 ≦ 0.7 (9)

Further, if Tm2 <180 ° C., the nonwoven fabric also shrinks by the thermal head, and if Tm2> 270 ° C., variations in sensitivity become large, which is not preferable. Tm
The value of 2 preferably satisfies the following expression (10).

200 ° C. ≦ Tm2 ≦ 265 ° C. (10)

Furthermore, [η] 1 × Tm1 / Tm2 ≦
[Η] 2 is not preferable because the sensitivity varies greatly, and Tm1 ≧ Tm2-25 is not preferable because the sensitivity itself is lowered.

In the relationship between Tm1 and Tm2, the following (11) is more preferably satisfied.

Tm1 <Tm2-40 (11)

In the present invention, the orientation parameter of the film portion and the nonwoven fabric portion is preferably 3 to 10, more preferably 3.5 to 8 or more, and particularly preferably 4 to 7 for both.

The crystal melting energy ΔHu of the film constituting the base paper of the present invention is preferably 3 to 11 cal /
g, more preferably 4 to 10 cal / g, particularly preferably 5 to 9 cal / g.

The area fraction of the open pores obtained by observing the support surface of the base paper of the present invention directly by the bright field transmission method of an optical microscope is preferably 3 to 80%, more preferably 5 to 50%, and particularly preferably It is preferably 10 to 30%. Further, when the opening is regarded as a circle, the average value of the equivalent circle diameter is preferably 5
˜100 μm, more preferably 10 to 60 μm, and particularly preferably 10 to 30 μm.

The fiber basis weight of the polyester nonwoven fabric constituting the base paper of the present invention is preferably 1 to 30 g / m ^2, more preferably 2 to 20 g / m ^2, particularly preferably is 3~16g / m ² .

The average fiber diameter of the single yarn constituting the polyester nonwoven fabric of the present invention is preferably 1 to 20 μm, more preferably 2 to 15 μm, and particularly preferably 3 to 12 μm.

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

The polyester film constituting the base paper of the present invention is preferably a biaxially stretched film and has a thickness of
The thickness is appropriately determined according to the sensitivity required for the base paper, but is preferably 0.1 to 5 μm, more preferably 0.1.
-4 μm, more preferably 0.1-3 μm.

The peel strength between the polyester film constituting the base paper of the present invention and the porous support is preferably 3 g / c.
m or more, more preferably 5 g / cm or more, and particularly preferably 10 g / cm or more.

In the base paper of the present invention, in order to prevent fusion at the time of perforation on one side of the film to be brought into 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 in the base paper of the present invention, it is preferable to apply the coating solution in the state 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 more remarkably exhibit the effects of the present invention, it is particularly preferable to apply the composition 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 various other atmospheres before providing a thin layer mainly composed of modified silicone.

[0049]

[Characteristics measurement method]

(1) Orientation parameter The orientation parameter was determined by laser Raman spectroscopy. For the film part, embed the base paper in PMMA resin,
Wet polishing is performed to form a cross section perpendicular to the longitudinal or width direction of the film. For example, Jobin Yvon / “Ramanor” U-1000I manufactured by Atago Bussan Co., Ltd. (light source: GLG3300 Ar ⁺ laser manufactured by NEC Corporation) 51
4.5 nm, microscope: Olympus Optical Co., Ltd. B
H-2 type objective lens × 100) was used to irradiate laser light perpendicularly to the cross section, and the Raman spectrum of the laser light polarized in the plane direction of the film and the laser light polarized in the thickness direction of the film was 1615 cm. ^When the peak intensities of the ⁻¹ band are I and IND,
The ratio I / IND was used as the orientation parameter of the film.

In the case of a non-woven fabric, it is not necessary to form a cross section, and laser light is radiated perpendicularly to the fiber axis by using the above-mentioned device, and laser light polarized in the length direction of the fiber and diameter direction of the fiber are used. 1615cm Raman spectra of by laser light polarized in ^- when the ^first peak intensity of the bands, respectively I and IND, and the ratio I / IND and orientation parameters of the nonwoven fabric.

(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.

Since the film and the non-woven fabric are a composite in which the non-woven fabric is adhered substantially without an adhesive, most of the non-woven fabric is peeled from the composite with cellophane tape and used as a sample of the non-woven fabric, and the film is observed under a microscope or the like. The non-woven fabric fiber was completely removed to obtain a sample.

(3) Crystal melting energy (ΔHu) Differential scanning calorimeter RDC220 manufactured by Seiko Denshi Kogyo Co., Ltd.
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) is measured, and this area (b) is 6.8c
It is calculated by the following formula as al / g.

6.8 × a / b = ΔHu (cal / g)

Separation of the film and the non-woven fabric is similar to the measurement of the melting point.

(4) Fiber diameter (μm) 10 photographs were taken at 10 arbitrary positions of the base paper with an electron microscope at a magnification of 2000, and 15 photographs were taken per one photograph.
The diameter of each fiber was measured, and this was carried out for 10 photographs to measure a total of 150 fiber diameters.

(5) Fiber areal weight (g / m ² ) A piece of base paper 20 cm × 20 cm was taken and its weight was measured and converted into weight per m ² .

(6) Intrinsic viscosity [η] After drying the sample at 105 ° C. for 20 minutes, 0.1 ± 0.00
5 g is weighed and o-chlorophenol 10 × 10 ⁻⁶ m
³ were dissolved by stirring 100 ° C. × 15 minutes in. After cooling,
The viscosity at 25 ° C. was measured by an AVM-10S type automatic viscosity meter manufactured by Yamatrabotik Co., Ltd. to obtain a specific viscosity ηs.
p was calculated and calculated from the following Huggins equation.

Ηsp / c = [η] + k ′ [η] 2c (where k ′ = 0.343, c is the solution 1 × 10 ⁻⁴ m
⁽ It is the concentration expressed in g dissolved in ³ )

(7) Crystallinity (%) The 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 determine the density. A density of 0% crystallinity is 1.335 g / c
m ³ , a density of 100% crystallinity is 1.455 g / cm ³
The crystallinity of the sample was calculated.

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

(9) Area Fraction (%) of Openings of Support Material The support surface of the base paper was directly observed by the bright-field transmission method of an optical microscope, and a high-definition image analysis device 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.

(10) Average value of equivalent circular diameters (μm) of the apertures of the support The support surface of the base paper was directly observed by the bright-field transmission method of an optical microscope, and a Hi-Vision compatible image analyzer manufactured by Pierce Co., Ltd. Using a monitor with a 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.

(11) Peel Strength (g / cm) Cellophane tape was attached 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.

(12) Evaluation of printability The prepared base paper was supplied to a printing machine "Lisograph" GR275 manufactured by Riso Kagaku Kogyo Co., Ltd., and a black solid of 10 mm on a side (■) was printed on A4 size by a thermal head type plate making system. A master was created by making a grid on the entire surface. The energy supplied to the thermal head was 30 μJ per dot. Plate making was performed by the master, and the perforated portion was observed with a scanning electron microscope at 100 times magnification, and the area of the perforated portion was measured. The measurement was performed for 10 fields of view with 150 per field, and the average value and the S / N ratio shown in the following formula were determined and evaluated according to the following criteria.

S / N ratio = 10 × log (average value of perforation area / standard deviation of perforation area) ² Sensitivity: ⊚ when the average value is 1400 × 10 ⁻¹² m ² or more, and 1000 × 10 in the average value. ^-12 m ² or more 1400 x
Those with a size of less than 10 ⁻¹² m ² are ◯, and the average value is 500 × 1.
The value of ^0-12 m ² or more and less than 1000 × 10 ⁻¹² m ² was evaluated as Δ, and the average value of less than 500 × 10 ⁻¹² m ^{2 was evaluated} as x.

Variation in sensitivity: A sample having an S / N ratio of 15 or more was evaluated as ⊚, a sample having an S / N ratio of 12 or more and less than 15 was evaluated as ◯, a sample having an S / N ratio of 8 or more and less than 12 was evaluated as Δ, and a sample having an S / N ratio of less than 8 as x.

Both ∘ and ∘ are used for practical use in terms of both sensitivity and variation.

[0069]

【Example】

Example 1 (Making of unstretched polyester nonwoven fabric) Pore diameter 0.35 m
m, using a rectangular spinneret having 100 holes and a spinneret temperature of 2
A polyethylene terephthalate raw material (melting point: 257 ° C., intrinsic viscosity: 0.48) was spun at 90 ° C. at a discharge rate of 30 g / min by a melt blow method, and the fibers were collected and wound on a net conveyor at a collection distance of 15 cm. . At this time, the amount of hot air blown from around the spinneret was set to 2.6 Nm ³ / min, and the temperature of the web immediately below the spinneret was set to 87 ° C. by the suction device provided on the net conveyor. The fiber basis weight of the unstretched nonwoven fabric is 142 g /
m ² , the average fiber diameter was 8.9 μm, the crystallinity was 1%, and the birefringence (Δn) was 0.003.

(Film Forming) Next, an ethylene terephthalate-ethylene isophthalate copolymer containing 0.4% by weight of silica having an average particle diameter of 1.5 μm (isophthalic acid 25
Mol% copolymerization, melting point 192 ° C., intrinsic viscosity 0.75) was pre-crystallized at 120 ° C. in an oven, then dried under reduced pressure at 150 ° C. for 3 hours in a rotary dryer, and an extruder having a screw diameter of 40 mm was used. , T-die mouthpiece extruded at a temperature of 270 ° C, cast on a cooling drum with a diameter of 300 mm to a thickness of 13 μm
Was produced.

On the unstretched film, the above-mentioned non-woven fabric was superposed, and a roll group consisting of five rolls in which the rotation directions of adjacent rolls were opposite and a sixth roll rotating in the same direction as the fifth roll were formed. The film surface of the first roll and the non-woven fabric surface of the second roll were passed through the fifth roll in a plow shape so that the non-woven fabric surface of the sixth roll was in contact with the non-woven fabric face of the second roll. At this time, the first roll and the second roll are metal rolls whose surfaces are plated with chrome, the third to sixth rolls are rolls coated with silicone rubber, and the surface temperature of the rolls is 83 ℃,
The second roll is 83 ℃ and the third roll is 90
℃, the fourth roll is 87 ℃, the fifth roll is 9
The temperature was 3 ° C and the sixth roll was 25 ° C. Further, the peripheral speeds of the first to fifth rolls were the same, and the peripheral speed difference was provided between the fifth and sixth rolls, whereby the film was stretched 3.5 times in the longitudinal direction.

Then, using a metering bar on the obtained laminated sheet, an aqueous dispersion of silene oil (concentration 2
%) Was applied to give a coating thickness of 9 μm.

Further, it was sent to a tenter type horizontal stretching machine,
Heated to 95 ° C with hot air and stretched 4.0 times in the width direction,
Heat treatment was performed at 120 ° C. for 10 seconds to prepare a heat-sensitive stencil sheet. The obtained base paper has an intrinsic viscosity of 0.7 in the film part.
2. The nonwoven fabric portion was 0.48. The basis weight of the nonwoven fabric was 10 g / m ² , the average fiber diameter was 5 μm, the thickness of the film alone was 0.9 μm, and the melting point was 192 ° C. Furthermore, the amount of amino-modified silicone oil applied is 0.04 g / m ^2.
Met.

(Evaluation Results) As summarized in Table 1, Table 2 and Table 3, evaluation was performed using the base paper finally obtained, and the base paper was found to have good sensitivity and variations in sensitivity. .

Examples 2 and 3 and Comparative Examples 1 and 2 Base papers were obtained in the same manner as in Example 1 except that the intrinsic viscosity of the raw materials of the film portion and the non-woven fabric portion was changed to Tables 1 and 2. The properties of the obtained base paper are also shown in Table 3. While the base paper of the present invention has good sensitivity and variation in sensitivity, when it is out of the range of the present invention, the sensitivity or the variation in sensitivity becomes worse. I understand.

Example 4 (Fabrication of unstretched polyester non-woven fabric) Pore size 0.35 m
m, using a rectangular spinneret having 100 holes and a spinneret temperature of 2
A polyethylene terephthalate raw material (melting point 257 ° C., intrinsic viscosity 0.55) was spun by a melt blow method at 90 ° C. and a discharge rate of 30 g / min, and fibers were collected and wound on a net conveyor at a collection distance of 15 cm. . At this time, the amount of hot air blown from around the die was set to 2.8 Nm ³ / min, and the temperature of the web immediately below the die was set to 87 ° C. by the suction device provided on the net conveyor. The fiber basis weight of the unstretched nonwoven fabric is 120 g /
m ² , the average fiber diameter was 9.5 μm, the crystallinity was 2%, and the birefringence (Δn) was 0.004.

(Film Forming) Next, an ethylene terephthalate-ethylene isophthalate copolymer (isophthalic acid 14%) containing 0.4% by weight of silica having an average particle size of 1.5 μm was prepared.
Mol% copolymerization, melting point 225 ° C., intrinsic viscosity 0.61) is pre-dried at 120 ° C. in an oven and then 175 in a rotary dryer.
At 275 ° C. using a 40 mm screw diameter extruder.
An unstretched film having a thickness of 13 μm was formed by casting on a cooling drum having a thickness of 13 mm.

The non-woven fabric was laminated on the unstretched film, and a roll group consisting of five rolls in which the rotation directions of adjacent rolls were opposite to each other and a sixth roll rotating in the same direction as the fifth roll were formed. The film surface of the first roll and the non-woven fabric surface of the second roll were passed through the fifth roll in a plow shape so that the non-woven fabric surface of the sixth roll was in contact with the non-woven fabric face of the second roll. At this time, the first roll and the second roll are metal rolls whose surfaces are plated with chrome, the third to sixth rolls are rolls coated with silicone rubber, and the surface temperature of the rolls is 83 ℃,
The second roll is 83 ℃, the third roll is 92
℃, the fourth roll is 89 ℃, the fifth roll is 9
The temperature was 6 ° C and the sixth roll was 25 ° C. Further, the peripheral speeds of the first to fifth rolls were the same, and the peripheral speed difference was provided between the fifth and sixth rolls, whereby the film was stretched 3.5 times in the longitudinal direction.

Then, using a metering bar on the obtained laminated sheet, an aqueous dispersion of silicone oil (concentration 2
%) Was applied to give a coating thickness of 9 μm.

Further, it was sent to a tenter type horizontal stretching machine,
Heated to 97 ° C with hot air, stretched 4.0 times in the width direction,
Heat treatment was performed at 120 ° C. for 10 seconds to prepare a heat-sensitive stencil sheet. The obtained base paper has an intrinsic viscosity of 0.6 in the film part.
1, the non-woven fabric portion was 0.53. The weight of the non-woven fabric was 9 g / m ² , the average fiber diameter was 5 μm, and the thickness of the film alone was 0.9 μm. Further, the amount of silicone oil applied was 0.04 g / m ² .

(Evaluation Results) As summarized in Table 1, Table 2 and Table 3, the evaluation was carried out using the finally obtained base paper. As a result, the base paper showed good sensitivity and variation in sensitivity. .

Examples 5 and 6 and Comparative Examples 3 and 4 Base papers were obtained in the same manner as in Example 1 except that the intrinsic viscosities of the raw materials of the film part and the non-woven fabric part were changed to Tables 1 and 2. The properties of the obtained base paper are also shown in Table 3. While the base paper of the present invention has good sensitivity and variation in sensitivity, when it is out of the range of the present invention, the sensitivity or the variation in sensitivity becomes worse. I understand.

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[Table 1]

[Table 2]

[Table 3]

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According to the present invention, the above-mentioned structure is provided.
The following effects are obtained. That is, since the sensitivity and the variation in sensitivity are small, the energy supplied to the thermal head of the printing machine can be reduced by using this base paper, and high definition,
This will reduce the plate making time.

Claims (1)

[Claims] 1. In a heat-sensitive stencil printing base paper in which a polyester film and a polyester non-woven fabric are adhered to each other substantially without an adhesive, the intrinsic viscosity and melting point (° C.) of the film are [η] 1 and Tm 1, respectively. A base paper for heat-sensitive stencil printing characterized by satisfying the following formulas (1) to (6), where [η] 2 and Tm 2 are the intrinsic viscosity and the melting point (° C.) of the nonwoven fabric, respectively. 0.5 ≦ [η] 1 ≦ 1.5 (1) 140 ° C. ≦ Tm1 ≦ 240 ° C. (2) 0.3 ≦ [η] 2 ≦ 0.8 (3) 180 ° C. ≦ Tm2 ≦ 280 ° C. (4) [Η] 1 × Tm1 / Tm2> [η] 2 (5) Tm1 <Tm2-25 (6)