JPH08332786A - Thermal stencil printing base sheet - Google Patents

Abstract

PURPOSE: To obtain an engraving master having high resolution faithful for an original by setting the applied energy of a thermal head and the rate of hole area of a thermoplastic resin film surface to be perforated to specific ranges. CONSTITUTION: A thermoplastic resin film and an ink permeable porous support are laminated together to form a thermal stencil printing base sheet perforated and engraved by a thermal head. In this case, the applied energy of the head is set to a range of 10 to 50μJ/dot, and the rate of hole area of the perforated thermoplastic resin film surface is set to a range of 10 to 60%. As the example of the film, polyester or polyamide are known, and from the point of perforating properties, the polyester film is suitable. The embodiments of the porous support, are nonwoven fabric or woven fabric made of natural fiber or synthetic fiber. The porous support made of the synthetic fiber can be manufactured by a method such as a known melt blowing method.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a heat-sensitive stencil printing base paper. More specifically, it relates to a halogen lamp, a xenon lamp, a flash bulb or the like for flash or infrared irradiation, or a pulsed irradiation of a laser beam or the like, and further relates to a heat sensitive stencil printing base paper which is perforated by a thermal head, etc. The present invention relates to a high-sensitivity heat-sensitive stencil printing base paper which is excellent in perforation plate-making properties due to the like.

[0002]

2. Description of the Related Art Thermal stencil printing has been known as a simple printing method replacing conventional copying machines. In heat-sensitive stencil printing, an ink-permeable porous support laminated with a heat-sensitive perforable thermoplastic resin film is used as the base paper, and the image of the document read by the sensor is sent as a digital signal to the thermal head, The thermoplastic resin film is heated and melted by the heat generated by the heating element to perform perforation plate making, and the printing ink is leached into the perforated portion from the side of the porous support to print on printing paper.

Conventionally, as base paper for heat-sensitive stencil printing, acrylonitrile film, polyester film,
Thermoplastic resin film such as vinylidene chloride film has a structure in which a porous support made of natural fiber, chemical fiber or synthetic fiber or thin paper, non-woven fabric, gauze or the like made of these is bonded with an adhesive. Known (for example, JP-A-51-2512, JP-A-51-2513, and JP-A-57-182495).

In recent years, heat-sensitive stencil printing has been required to have high-definition and high-quality printability similar to offset printing.
It is required to shorten the plate making time. Therefore, a fully automatic thermal stencil printing machine has been developed in which the thermal elements of the thermal head are highly densified to increase the resolution and the applied energy is reduced to reduce the plate making speed. However, the conventional heat-sensitive stencil printing base paper has a limit to satisfy these requirements.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a heat sensitive stencil printing base paper having high sensitivity and high resolution which cannot be realized by the conventional heat sensitive stencil printing base paper.

[0006]

As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that the defect of the conventional base paper can be improved by having a specific opening property, and the present invention has been completed. It was done.

That is, according to the present invention, a thermoplastic resin film and an ink-permeable porous support are bonded together,
In a heat-sensitive stencil printing base paper that is perforated by a thermal head, the applied energy of the thermal head is 1
The heat-sensitive stencil printing base paper is characterized in that the open area ratio of the surface of the punched thermoplastic resin film is in the range of 10 to 60% in the range of 0 to 50 μJ / dot.

The thermoplastic resin film in the present invention is
For example, polyester, polyamide, polypropylene, polyethylene, polyvinyl chloride, polyvinylidene chloride resin film, or a conventionally known thermoplastic resin film such as a copolymer resin thereof can be used, but a polyester film is particularly preferable from the viewpoint of piercing property. Used.

Polyester used in the polyester film is preferably polyethylene terephthalate, a copolymer of ethylene terephthalate and ethylene isophthalate, a copolymer of hexamethylene terephthalate and cyclohexane dimethylene terephthalate, or the like. Particularly preferably, a copolymer of ethylene terephthalate and ethylene isophthalate, a copolymer of hexamethylene terephthalate and cyclohexane dimethylene terephthalate, or the like can be used to improve the perforation sensitivity.

In the thermoplastic resin film of the present invention, if necessary, an organic lubricant such as a flame retardant, a heat stabilizer, an antioxidant, an ultraviolet absorber, an antistatic agent, a pigment, a dye, a fatty acid ester, or a wax, or An antifoaming agent such as polysiloxane can be blended. Further, slipperiness can be imparted, if necessary. The method for imparting slipperiness is not particularly limited, but examples thereof include clay, mica, titanium oxide, calcium carbonate, kaolin, talc, inorganic particles such as wet or dry silica, organic particles containing acrylic acid, styrene and the like as constituent components. And the like, a method of so-called internal particles for depositing a catalyst or the like added during the polyester polymerization reaction, a method of applying a surfactant, and the like.

The porous support in the present invention is not particularly limited as long as it can pass the printing ink and does not cause thermal deformation when the film is perforated by heating. Examples thereof include non-woven fabrics, woven fabrics, tissue papers, screen gauze and the like, which are made of natural fibers, recycled fibers, synthetic fibers or the like or a mixture thereof. In the present invention, a non-woven fabric containing synthetic fibers as a main component is preferably used from the viewpoint of uniform ink transmission. As the synthetic fiber, for example, polyester, polyamide, polyphenylene sulfide, polyacrylonitrile, polypropylene, polyethylene or a copolymer thereof is used. These synthetic fibers may be used alone, or may be used in combination of two or more kinds, and may contain natural fibers and regenerated fibers, but mainly polyester fibers from the viewpoint of support strength. Those used are particularly preferable. As the polyester used for the polyester fiber, polyethylene terephthalate, polyethylene naphthalate, polycyclohexanedimethylene terephthalate, a copolymer of ethylene terephthalate and ethylene isophthalate, and the like can be preferably used. From the viewpoint of thermal dimensional stability, polyethylene terephthalate, polyethylene naphthalate and the like can be particularly preferably used.

The synthetic fiber of the present invention may optionally contain an organic lubricant such as a flame retardant, a heat stabilizer, an antioxidant, an ultraviolet absorber, an antistatic agent, a pigment, a dye, a fatty acid ester, a wax, or a polysiloxane. The defoaming agent, etc. can be added.

The polyesters preferably used for the film and the support fiber of the present invention are polyesters containing an aromatic dicarboxylic acid, an aliphatic dicarboxylic acid or an alicyclic dicarboxylic acid and a diol as main constituents. 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, etc. are used. Of these, terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid and the like can be preferably used. As the aliphatic dicarboxylic acid component, for example, adipic acid, suberic acid, sebacic acid, dodecanedioic acid, or the like can be used, and among them, adipic acid or the like can be preferably used. 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'-β-
Hydroxyethoxyphenyl) propane and the like can be used. Among them, ethylene glycol is preferably used. Only one of these diol components may be used,
You may use 2 or more types together.

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 polycondense while removing the excess diol component, or a dialkyl as the acid component There is a method in which an ester is used, an ester exchange reaction is carried out between the ester and a diol component, and then polycondensation is carried out in the same manner as described above. At this time, if necessary, a conventionally known alkali metal, alkaline earth metal, manganese, cobalt, zinc, antimony, germanium, titanium compound or the like can be used as a reaction catalyst.

The thermoplastic resin film in the present invention is preferably a stretched oriented film, and the orientation degree (Δn) is preferably 0.05 or more, more preferably 0.08 or more, and particularly preferably 0.10. When the orientation degree is 0.05 or more, the hole expansion at the time of drilling becomes good.

The thermoplastic resin film in the present invention is
The crystallinity is preferably 35% or less, more preferably 30.
% Or less, particularly preferably 25% or less. If the crystallinity is 35% or less, the perforated shape will be good.

The thickness (t) of the thermoplastic resin film in the present invention is usually 0.1 to 10 μm, preferably 0.1 to 5.0 μm, more preferably 0.1 to 3.0 μm.
m, particularly preferably 0.1 to 2 μm. Thickness is 10
If it is less than μm, the perforation sensitivity does not decrease, and
If it is 1 μm or more, the film will not be broken during transportation.

The thermoplastic resin film in the present invention is
The crystal melting energy (ΔHu) is preferably 3 to 11 cal / g, more preferably 5 to 10 cal / g.
Is. When ΔHu is 3 cal / g or more, the perforation sensitivity of the film is good, and ΔHu is 11 cal / g.
When it is at most g, the perforated shape of the film will be stable.

The thermoplastic resin film in the present invention is
The product (ΔHu × t) of the film thickness (t) and the crystal melting energy (ΔHu) is preferably 50 cal · μm / g.
Or less, more preferably 40 cal · μm / g or less, particularly preferably 30 cal · μm / g or less. ΔHu ×
If t is 50 cal · μm / g or less, the perforation sensitivity is good.

The melting point (Tm ₁ ) of the thermoplastic resin film in the present invention is usually 260 ° C. or lower, preferably 250 ° C. or lower, more preferably 240 ° C. or lower, particularly preferably 230 ° C. or lower. Melting point of film is 260 ℃
If it is below, the perforation sensitivity will not be lowered even in the low applied energy region of the thermal head.

The thermoplastic resin film in the present invention is
The heat shrinkage percentage is preferably 10% or more at 120 ° C., more preferably 20% or more, and particularly preferably 30% or more. When the heat shrinkage is 10% or more, the expansion of the holes after the film is punched is good.

The thermoplastic resin film in the present invention is
Heat shrinkage stress is preferably 300 g / mm ² at 100 ° C
Or more, more preferably 350 g / mm ² or more, particularly preferably 400 g / mm ² or more. Heat shrinkage stress is 3
If it is 00 g / mm ² or more, the hole shape after melt perforation becomes uniform.

The fiber basis weight of the porous support in the present invention is usually 1 to 20 g / m ² , preferably 2 to 16
g / m ² , more preferably ² to 14 g / m ² . When the basis weight is 20 g / m ² or less, the ink holding property is good, and the printed image does not fade even if the printing speed is increased. When the basis weight is 1 g / m ² or more, the ink permeability is good, a clear image can be obtained, and a base paper excellent in transportability can be obtained.

The average diameter of the fibers constituting the porous support of the present invention is usually 0.5 to 30 μm, preferably 1 to 20.
μm, more preferably 1 to 10 μm, particularly preferably 1
~ 5 μm. When the average diameter is 30 μm or less, sufficient strength as a support can be obtained, and thus the transportability is excellent.
Further, when the average diameter is 0.5 μm or more, a support having a uniform fiber distribution can be obtained, so that a base paper having a uniform ink permeability can be obtained.

The fibers constituting the porous support of the present invention may all have the same diameter, or fibers having different fiber diameters may be mixed. Further, a multi-layer structure in which fibers having different fiber diameters are laminated stepwise may be used. In the case of a multilayer structure, at least the layer facing the film should be 10μ
It is more preferable to use fibers of m or less and the remaining layers of fibers of 10 μm or more in terms of the balance between image clarity and support strength. In the case of a multi-layer structure, the fiber unit weight of the layer facing the film is more preferably 1 to 5 g / m ² .

The fibers constituting the porous support of the present invention are particularly preferably stretch-oriented. Degree of fiber orientation (Δ
n) is usually 0.1 or more, preferably 0.12 or more, more preferably 0.14 or more. When the degree of orientation is 0.1 or more, the fiber strength is high and sufficient support strength is obtained, so that a master having excellent transportability can be obtained.

The crystallinity of the fibers constituting the porous support of the present invention is usually preferably 20% or more, more preferably 25% or more, particularly preferably 30% or more.
When the crystallinity is 20% or more, sufficient heat resistance as a support can be obtained.

The fibers constituting the porous support of the present invention are
In order to impart affinity with ink, the surface of the fiber may be chemically treated with acid, alkali, etc. or corona treated, if necessary.
You may perform low temperature plasma processing etc.

The Oken type smoothness on the film side of the base paper of the present invention is preferably 1,000 seconds or more, more preferably 200.
It is 0 second or more, more preferably 3000 seconds or more, and particularly preferably 4000 seconds or more. Oken type smoothness is 1000
If the time is at least 2 seconds, the adhesion with the thermal head will be good, and therefore no perforation failure will occur.

The peel strength between the thermoplastic resin film constituting the base paper of the present invention and the porous support is preferably 1 g / cm.
Or more, more preferably 5 g / cm or more, and particularly preferably 10 g / cm or more. When the peel strength is 1 g / cm or more, wrinkles and tears are less likely to occur during the transport of the film, and the running stability is excellent.

The melting point (Tm ₁ ) of the thermoplastic resin film constituting the base paper of the present invention and the melting point (Tm ₂ ) of the fibers constituting the porous support are preferably Tm ₁ ≦ Tm ₂ , and more preferably Has a temperature difference of 5 ° C. or higher, particularly preferably 10 ° C. or higher. When Tm ₁ ≦ Tm ₂ , the support is not thermally deformed when the film is perforated.

The base paper of the present invention can be perforated with an applied energy of a thermal head of 10 to 50 μJ / dot, preferably 10 to 40 μJ / dot, more preferably 10
Perforation plate making is possible at ˜30 μJ / dot. Further, in the base paper of the present invention, the open area ratio of the film surface is in the range of 10 to 60% in the applied energy range of the thermal head. It is preferably 10 to 50%. Open area ratio is 10
If it is less than%, the ink transmission becomes insufficient and the printing may be faint. On the other hand, when the open area ratio exceeds 60%, the independent perforating property is deteriorated and the ink is excessively flowed out, so that the printing is bleeding or the show-through is likely to occur.

Any method can be adopted to bring the base paper of the present invention into the above range. In particular, an unstretched polyester film and a porous support made of unstretched synthetic fiber are heat-bonded and co-stretched. This is most preferably achieved.

The porous support made of synthetic fiber preferably used in the present invention can be produced by a direct melt spinning method such as a conventionally known melt blow method or spun bond method. The intrinsic viscosity of the polymer used is usually preferably 0.4 or more, more preferably 0.45 or more.

For example, in the melt blow spinning method, when the molten polymer is discharged from the spinneret, hot air is blown from the periphery of the spinneret, the polymer discharged by the hot air is made finer, and then the net conveyor is placed at an appropriate position. It is manufactured by spraying it onto the surface to form a web. Since the web is sucked together with the hot air by the suction device provided on the net conveyor, it is collected before the fibers are completely solidified. That is, the fibers of the web are collected while being fused to each other. By appropriately setting the collection distance between the die and the net conveyor, the fusion degree of the fibers can be adjusted. Further, the fiber diameter of the web can be arbitrarily set by appropriately setting the polymer discharge amount, the hot air temperature, and the hot air flow rate, and the fiber basis weight of the web can be arbitrarily set by appropriately adjusting the conveyor speed. The fibers melt-spun are finely pulverized by hot air pressure but not stretched and solidified in a so-called non-oriented state.

Similarly, in the spunbond method, the polymer discharged from the die is pulled by an air ejector, and the obtained filament is collided with a collision plate to open the fiber,
It is manufactured by collecting it on a conveyor to form a web. By appropriately setting the pressure and flow rate of the ejector, the degree of fiber orientation can be adjusted, and by reducing the pressure and flow rate to reduce the spinning speed, a fiber web having a low degree of orientation can be obtained. Further, by adjusting the cooling rate of the discharged polymer, fiber webs having different crystallinity can be obtained.

For example, the crystallinity of the unstretched fibers preferably used in the present invention is usually preferably 20% or less, more preferably 15% or less in order to facilitate the adhesion to the film.
It is particularly preferably 10% or less. Further, the degree of orientation of the unstretched fiber is usually preferably Δn = from the viewpoint of co-stretchability.
0.03 or less (ΔM: birefringence), more preferably 0.0
It is 2 or less, particularly preferably 0.01 or less.

As the polyester film preferably used in the present invention, an unstretched film can be produced by using the above polyester and extruding a polymer on a cast drum by, for example, 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 polyester is
Usually, it is preferably 0.5 or more, more preferably 0.6 or more. When the intrinsic viscosity is 0.5 or more, the film-forming stability is good, and it is particularly easy to cast a thin product.

The polyester film preferably used in the present invention and the porous support made of synthetic fiber are preferably fused to each other. For fusion, it is generally preferable to perform thermocompression bonding under pressure while heating the polyester film and the porous support. The method of thermocompression bonding is not particularly limited, but thermocompression bonding with a heating roll is particularly preferable from the viewpoint of processability. In this case, the heating roll is preferably a combination of a metal roll and a rubber roll such as silicone. In the case of polyester film, the temperature during thermocompression bonding is the glass transition point (Tg) and the cold crystallization temperature (T
between cc) is preferred. The pressure is preferably a roll linear pressure in the range of 0.1 to 10 kg / cm.

In the present invention, it is preferable that the unstretched polyester film and the unstretched porous support are co-stretched in a state of being thermocompression bonded. By co-stretching in the thermocompression bonded state, the film and the support are suitably stretched without peeling.

At this time, the fibers of the support form a net-like body which is fused to each other at a part of the contact points between the fibers. Further, at some of the fusion points, a thin film extending between the fibers is formed. That is,
By forming the porous support in this way,
The strength of the support is stable. Furthermore, by co-stretching the both together, the fibers of the support function 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 and may be either uniaxial stretching or biaxial stretching, but in the present invention, in terms of the degree of orientation of the film and the uniform dispersibility of the support fibers. Biaxial stretching is more preferred. The biaxial stretching may be either a sequential biaxial stretching method or a simultaneous biaxial stretching method, but in the present invention, the sequential biaxial stretching is preferred. In the case of the sequential biaxial stretching, it is general that after the longitudinal stretching by the heating roll group, the transverse stretching is generally performed by the tenter, but it may be reversed. As the heating roll, a metal roll, a ceramic roll, a silicone rubber roll, or the like is used, but stretching is preferably performed between the ceramic rolls, between the ceramic and the rubber rolls, or between the rubber rolls. Also,
The nip pressure during stretching is preferably linear pressure in the range of 0.1 to 10 kg / cm. In the case of polyester resin, the stretching temperature is glass transition temperature (Tg) and cold crystallization temperature (Tc).
It is preferably between c). Further, in order to uniformly heat the film during stretching, only the support fibers may be preheated before being supplied. The stretching ratio is not particularly limited, but in the case of a polyester film, it is usually preferable that the length and the width are 2 to 2 respectively.
It is 8 times, more preferably 3 to 8 times. Further, after biaxial stretching, it may be re-stretched longitudinally or laterally or longitudinally and laterally.

After that, the base paper of the present invention after biaxial stretching may be heat-treated. The heat treatment temperature is not particularly limited and is appropriately determined depending on the type of polymer used, but in the case of a polyester film, it is usually preferably between the glass transition temperature (Tg) and the melting point (Tm) of the polymer,
A suitable treatment time is usually 0.5 to 60 seconds.

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.
When such aging is adopted, curling and wrinkling are less likely to occur during storage of the base paper or in the printing machine, which is particularly preferable.

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

In the present invention, the film having a thin fusion point means a so-called "duck's foot watering" shape, or "frog's foot watering" shape, or a "fold" shape, usually two or more. Formed across the fibers.

In the base paper of the present invention, it is preferable to apply a release agent to the film surface in order to prevent fusion with a thermal head or the like. As a release agent, silicone oil,
It is possible to use a silicone resin, a fluorine resin, a surfactant, a wax release agent, or the like. Various additives may be used in combination with these release agents within a range that does not impair the effects of the present invention. For example, antistatic agents, heat-resistant agents, antioxidants, organic particles, inorganic particles, pigments and the like can be used.

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

The release agent may be applied at any stage before or after stretching the film. The coating method is not particularly limited, but it is preferable to use a roll coater, a gravure coater, a reverse coater, a bar coater or the like. If necessary, the coated surface may be subjected to corona discharge treatment in air or other various atmospheres before coating with the release agent.

[Characteristic Measuring Method] (1) Applied Energy (μJ / dot) The applied energy Q (μJ / dot) is the applied voltage of the thermal head is V (v), the resistance is R (Ω), and the applied time is T
(Μsec) and calculated by the following equation. Q = V ² · T / R (μJ / dot)

(2) Open area ratio (%) The prepared base paper was supplied to a printing machine lithograph (GR275) manufactured by Riso Kagaku Kogyo Co., Ltd.
A black solid (■) in a grid pattern was used as a document, and the applied energy of the thermal head was changed between 5 and 70 μJ / dot for plate making. The applied energy was changed by changing the applied voltage of the thermal head. The film side of the plate-making master is made by Topcon Corporation, scanning electron microscope D
A photograph was taken at 100 times magnification in S130. Then
Using a Hi-Vision image analyzer manufactured by Pierce Co., Ltd.
The total opening area S (μm ² ) of the punched portion corresponding to the number of 150 elements of the thermal head was measured, and the element pitch of the thermal head was P ₁ (μm) and the running pitch was P ₂ (μm), The open area ratio was calculated by. Open area ratio = S × 100 / (P ₁ · P ₂ × 150)

(3) Evaluation of printability [Gradation] Using the above printing machine, a solid pattern of 24 gradations by a combination of various symbols and a matrix is printed as an original with an applied energy of 30 μJ / dot, and printed.
Gradation was evaluated according to the following criteria. ◎: 19 to 24 gradations can be discriminated ○: 13 to 18 gradations can be discriminated △: 7 to 12 gradations can be discriminated ×: 6 gradations or less can be discriminated

[Resolution] Similarly, a black solid (■) with a side of 10 mm and a fine line of 5 lines / mm were printed as an original, and the fine line of the printed matter was visually judged as follows. ◎: Fine lines without any breaks ○: Slight breaks △: Clear breaks ×: Marked breaks

[Image Quality] The optical density of the solid black portion of the printed matter was measured by a Macbeth densitometer.

(4) Melting point (Tm, ° C) Differential scanning calorimeter RDC22 manufactured by Seiko Instruments Inc.
Using 0 type, sample 5 mg was collected and the temperature rising rate from room temperature was 2
It was determined from the peak temperature of the endothermic curve when the temperature was raised at 0 ° C / min.

(5) Crystal melting energy (ΔHu, ca
1 / g) Differential scanning calorimeter RDC22 manufactured by Seiko Instruments Inc.
It is determined from the area of the film when it is melted using the 0 type. This area is the area from the baseline to the absorption side by increasing the temperature, and the area until returning to the position of the baseline when the temperature is further increased. Find (a). Same DS
In (indium) was measured under the condition of C, and the area (b) was determined to be 6.8 cal / g by the following formula. 6.8 × a / b = ΔHu (cal / g)

(6) Intrinsic viscosity [η] After the sample was dried at 105 ° C. for 20 minutes, 6.8 ± 0.00
5 g was weighed and 160 ° C x 1 in o-chlorophenol
It was dissolved by stirring for 5 minutes. After cooling, the viscosity at 25 ° C. was measured with a Yamatrabotic AVM-10S type automatic viscosity meter.

(7) Crystallinity (%) A sample was placed in a density gradient tube made of a mixed solution of n-heptane and carbon tetrachloride, and the value was read after 10 hours or more to determine the density. In the case of polyester resin, the crystallinity of the sample was calculated with the density of 0% crystallinity of 1.335 g / cm ³ and the density of 100% crystallinity of 1.455 g / cm ³ .

(8) Heat shrinkage rate (%) A 15 cm square sample was marked with 10 cm square and placed in a hot-air circulating thermostat set to a predetermined temperature.
The dimensions were measured after standing at 20 ° C. for 10 minutes, and the dimensional change was divided by the original dimensions and expressed as a percentage.

(9) Heat shrinkage stress (g / mm ² ) A sample having a width of 2 cm and a length of 10 cm is taken and fixed to a chuck with a load cell at a chuck distance of 5 cm. Then, heating is performed from room temperature to a predetermined temperature by circulating hot air. The change in sample length due to heating and the change in load due to shrinkage were recorded on a recorder, and the load was divided by the cross-sectional area of the sample before heating to obtain the shrinkage stress.

(10) Fiber diameter (μm) An arbitrary portion of the sample was photographed with an electron microscope at a magnification of 2000 times, and the diameter of any 5 fibers was measured per photograph, and a total of 150 fibers were measured. The fiber diameter was measured and the average value was calculated.

(11) Fiber areal weight (g / m ² ) A sample is cut into 20 cm × 20 cm and the weight is m.
Converted to the weight per ² .

(12) 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.
The 180-degree peel test method according to

[0064]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited thereto. Example 1 Using a rectangular spinneret having a hole diameter of 0.3 mm and 900 holes, the spinneret temperature was 290 ° C., the hot air temperature was 295 ° C., and the hot air flow rate was 4.
At 00 Nm ³ / h, polyethylene terephthalate resin raw material ([η] = 0.5, Tm = 256 ° C.) was spun by the melt-blowing method, and the fiber was collected and wound on a conveyor at a collection distance of 18 cm. An unstretched nonwoven fabric having a basis weight of 100 g / m ² was prepared.

Then, polyethylene terephthalate 85
Copolyester resin raw material ([η] = 0.65, T
m = 226 ° C.) and a substantially amorphous copolyester (KODAR DETG manufactured by Eastman Kodak Co., Ltd.
6763, 1,4-cyclohexadimethanol (33 mol%) at a weight ratio of 80:20 and a screw diameter of 4
An unstretched film was produced by extruding at a T-die die temperature of 270 ° C. using a 0 mm extruder and casting on a cooling drum having a diameter of 300 mm.

The above-mentioned non-woven fabric is superposed on the unstretched film and supplied to a heating roll to obtain a roll temperature of 75 ° C. and a linear pressure of 1 k.
After heat-bonding at g / cm and then stretching at 90 ° C. between heating rolls (rubber rolls) at a nip pressure of 0.5 kg / cm in the length direction (MD direction) by a factor of 3.6, the mixture is sent to a tenter type stretching machine. The film was stretched 4.3 times in the width direction (TD direction) at 95 ° C. and further heat-treated at 120 ° C. in a tenter to prepare a heat-sensitive stencil sheet. On the film surface of the base paper, a silicone release agent (SH-200, manufactured by Toray Dow Corning Silicone Co., Ltd.) was used, and the weight after drying was 0.06 g / m 2.
^{2 were} applied. The fiber basis weight of the obtained base paper is 8.2 g / m.
² , average fiber diameter 3.3μm, film thickness 0.6
μm.

Example 2 In Example 1, 76 mol% of polyethylene terephthalate,
Copolyester resin raw material consisting of 24 mol% of polyethylene isophthalate ([η] = 0.66, Tm = 19
6 ° C.) was extruded at a T-die spinneret temperature of 270 ° C. using an extruder having a screw diameter of 40 mm and cast on a cooling drum having a diameter of 300 mm to prepare an unstretched film.

On the unstretched film, the non-woven fabric of Example 1 was overlaid, supplied to a heating roll and thermally bonded at a roll temperature of 75 ° C. and a linear pressure of 0.5 kg / cm, and then heated at 90 ° C. (rubber roll). In between, after stretching 3.5 times in the length direction at a nip pressure of 1 kg / cm, it is fed into a tenter type stretching machine, stretched 4.0 times in the width direction at 95 ° C, and further heat treated at 100 ° C in a tenter. To prepare a heat-sensitive stencil sheet. On the film side of the base paper, a silicone release agent (SH-200, manufactured by Toray Dow Corning Silicone Co., Ltd.)
Was applied at a weight after drying of 0.06 g / m ² . The fiber basis weight of the obtained base paper was 9.8 g / m ² , the average fiber diameter was 4.0 μm, and the film thickness was 0.8 μm.

Example 3 A polyethylene terephthalate resin raw material ([η] = 0.65, using a die having a hole diameter of 0.30 mm and 120 holes)
(Tm = 261 ° C.) was spun at a melting temperature of 290 ° C. and dispersed and collected on a conveyor by an air ejector at a spinning speed of 850 m / min to prepare a nonwoven fabric having a fiber basis weight of 100 g / m ² .

Then, polyethylene terephthalate 55
Wt% and 45 wt% polybutylene terephthalate blended polyester resin raw material ([η] = 0.63, T
m = 220 ° C., 251 ° C.) was 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 produce an unstretched film.

The non-woven fabric was laid on the unstretched film and fed to a heating roll to obtain a roll temperature of 80 ° C. and a linear pressure of 2 k.
A laminated sheet was produced by thermocompression bonding at g / cm. The laminated sheet was stretched 3.3 times in the length direction at a nip pressure of 3 kg / cm between heating rolls (rubber rolls) at 95 ° C., and then fed into a tenter type stretching machine, and 4.0 times in the width direction at 95 ° C. It was stretched. Further, heat treatment was carried out at 100 ° C. inside the tenter to prepare a heat sensitive stencil sheet. On the film surface of the base paper, a silicone release agent (SH-200, manufactured by Toray Dow Corning Silicone Co., Ltd.) was used, and the weight after drying was 0.06 g / m 2.
^{2 were} applied. The fiber basis weight of the obtained base paper is 11.0 g /
m ² , the average fiber diameter is 4.8 μm, and the film thickness is 1.
It was 2 μm.

Example 4 In Example 3, a polyhexamethylene terephthalate resin raw material ([η] = 0.66, Tm = 145 ° C.) was extruded at a T-die die temperature of 200 ° C. using an extruder having a screw diameter of 40 mm. An unstretched film was produced by casting on a cooling drum having a diameter of 300 mm.

The non-woven fabric of Example 3 was superposed on the unstretched film, supplied to a heating roll and thermally bonded at a roll temperature of 60 ° C. and a linear pressure of 0.3 kg / cm, and then heated at 70 ° C. (rubber roll). In between, after stretching 3.3 times in the length direction at a nip pressure of 0.5 kg / cm, it is fed into a tenter type stretching machine and stretched 4.0 times in the width direction at 80 ° C, and further at 100 ° C in the tenter. It heat-processed and the raw paper for heat sensitive stencil was produced. On the film side of the base paper, a silicone release agent (SH-200, manufactured by Toray Dow Corning Silicone Co., Ltd.)
Was applied at a weight after drying of 0.06 g / m ² . The fiber basis weight of the obtained base paper was 9.0 g / m ² , the average fiber diameter was 5.4 μm, and the film thickness was 1.0 μm.

Comparative Example 1 In Example 1, the average fiber diameter was 2.7 μm and the basis weight was 18 g / m ^2.
The non-woven fabric of Then, a polyethylene terephthalate resin raw material ([η] = 0.65, Tm = 261 ° C.) was 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 was produced.

The unstretched film was stretched 3.0 times in the length direction, then fed to a tenter type stretching machine, stretched 3.8 times in the width direction at 95 ° C., and further heat treated at 160 ° C. in a tenter. A biaxially stretched film having a thickness of 2.2 μm was produced. The non-woven fabric and the film were overlaid, heat-bonded with a laminator at 80 ° C., and a silicone release agent was applied to the film surface to prepare a heat-sensitive stencil sheet.

Comparative Example 2 In Example 3, the spinning speed was 4000 m / min and the average fiber diameter was 1
A porous support made of a non-woven fabric of 0 μm and a basis weight of 15 g / m ² was prepared. Next, the copolymerized polyester resin film consisting of 85 mol% polyethylene terephthalate and 15 mol% polyethylene isophthalate collected in Example 1 was stretched 3 × 3 times in the length and width with a stretcher to obtain 160 ° C. ×
Heat treatment was performed for 10 seconds to prepare a biaxially stretched film having a thickness of 2.5 μm. The porous support and the polyester film were bonded together using a vinyl acetate resin adhesive. Next, a silicone release agent was applied to the film surface to prepare a heat sensitive stencil sheet.

Table 1 shows the constitutions of the base papers of the above Examples and Comparative Examples. The evaluation results are shown in Table 2 (open area ratio), Table 3
(Printability).

[0078]

[Table 1]

[0079]

[Table 2]

[0080]

[Table 3]

As can be seen from Tables 1, 2 and 3, the base paper according to the present invention has a plate making energy of 1 using a thermal head.
In the range of 0 to 50 μJ / dot, the open area ratio of the base paper film surface is 10 to 60%. The product printed using the base paper of the present invention has excellent gradation and high resolution. Further, since the base paper of the present invention can be used for plate making with low energy, the plate making time can be shortened.

[0082]

The present invention has the above-mentioned structure,
In plate making such as a thermal head, it is possible to make a plate with low applied energy so that it has high sensitivity, and since the aperture area ratio of the film is specified, a high resolution plate making master faithful to the original can be obtained. . Therefore, the printed matter obtained by stencil printing using this base paper has high definition and high image quality, and is excellent in printing sharpness. Further, since the base paper of the present invention can be used for plate making with low energy, the plate making time can be shortened.

Claims (3)

[Claims] 1. A heat-sensitive stencil printing base paper which is obtained by laminating a thermoplastic resin film and an ink-permeable porous support, and is perforated by a thermal head. The applied energy of the thermal head is 10 to 50 μJ / A heat-sensitive stencil printing base paper, characterized in that the open area ratio of the surface of the thermoplastic resin film to be punched is in the range of 10 to 60% in the range of dots. 2. The heat-sensitive stencil printing base paper according to claim 1, wherein the thermoplastic resin film is made of a resin mainly composed of polyester. 3. The heat-sensitive stencil printing base paper according to claim 1, wherein the porous support is mainly composed of polyester fiber.