JP2000335136A - Heat-sensitive stencil film and heat-sensitive stencil master - Google Patents

Abstract

An object of the present invention is to provide a high-sensitivity heat-sensitive stencil film and a heat-sensitive stencil master that are not realized by the prior art and have excellent perforation at low energy. is there. The heat-sensitive stencil film of the present invention is a biaxially stretched film made of polyester, and the TMA shrinkage of the biaxially stretched film is measured (at a heating rate of 10 ° C. /
Min, and a constant load of 0.5 g). X (max) ≧ 25% 40 ° C. ≦ T (start) ≦ 80 ° C. T (max) −T (start) ≦ 50 ° C. where X (max): maximum shrinkage [%] T (start): shrinkage start temperature [° C.] T (max): Maximum shrink temperature [° C.] Further, the thermosensitive stencil master of the present invention is characterized in that such a thermosensitive stencil film and a porous support are bonded to each other. .

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a thermal head,
Alternatively, regarding a heat-sensitive stencil film and a heat-sensitive stencil master, which are perforated by a halogen lamp, a xenon lamp, a flash lamp, a laser beam, or the like,
More specifically, the present invention relates to a film and a master which are excellent in perforation sensitivity and particularly excellent in perforation at a low energy by a thermal head.

[0002]

2. Description of the Related Art Conventionally, as a heat-sensitive stencil master, for example, Japanese Patent Application Laid-Open No.
As proposed in JP-A-182495 and the like, a thermoplastic resin film such as a vinylidene chloride film, a polyester film, a polypropylene film, and the like, a natural fiber, a chemical fiber or a synthetic fiber, or a thin paper, a nonwoven fabric, a gauze, or the like obtained by mixing these fibers. There is known a structure in which a constituted porous support is bonded with an adhesive.

However, recently, high resolution is required for printed materials. For example, in the case of perforation by a thermal head, in order to obtain a high resolution, each head is made smaller and the head heating cycle is shortened, so that perforation per unit area is performed. Attempts have been made to increase the number. In such a case, it is necessary to reduce the energy supplied to the individual heads in order to obtain an appropriate size of perforations in a short time and to reduce the load on the thermal head and extend the life. Piercing with low energy,
That is, higher sensitivity of the film is desired.

However, JP-A-2-158391, JP-A-7-276839, and JP-A-10-1
For example, Japanese Patent Application Laid-Open Nos. Sho 62-282983 and Sho 63-160895, which have been proposed in, for example, Japanese Patent Application Laid-Open No. Films and the like that have been proposed in the specification of heat shrinkage properties are known, but none of these are insufficient in sensitivity.
Further higher sensitivity has been desired.

[0005]

SUMMARY OF THE INVENTION The present invention provides a high-sensitivity heat-sensitive stencil film excellent in perforation at low energy and a heat-sensitive stencil master using the film, which could not be realized by the prior art. Is to be provided.

[0006]

The present invention employs the following means in order to solve the above-mentioned problems. That is, the film for heat-sensitive stencil printing of the present invention is a biaxially stretched film made of polyester, and the TMA heat shrinkage of the biaxially stretched film is measured (at a heating rate of 10 ° C. /
Min, and a constant load of 0.5 g).

X (max) ≧ 25% 40 ° C. ≦ T (start) ≦ 80 ° C. T (max) −T (start) ≦ 50 ° C. where X (max): maximum shrinkage [%] T (start): Shrinkage onset temperature [° C] T (max): Maximum shrinkage temperature [° C] The heat-sensitive stencil master of the present invention is characterized in that the heat-sensitive stencil film and the porous support are joined together. Things.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention focuses on the functions of a heat-sensitive stencil printing film and a master, and the mechanism of perforation stencil printing. As a result, the heat shrinkage characteristics of the film are set within a specific range. The present invention has been found to be solved at once, and the present invention has been completed.

The film constituting the heat-sensitive stencil printing film and the heat-sensitive stencil printing master of the present invention is a biaxially stretched film made of polyester, and the heat shrinkage property of the biaxially stretched film is measured by a thermomechanical measuring apparatus TMA. The heat shrinkage characteristic obtained from the heat shrinkage rate curve measured under the conditions of a temperature rising rate of 10 ° C./min and a constant load of 0.5 g needs to satisfy the following equation.

X (max) ≧ 25% 40 ° C. ≦ T (start) ≦ 80 ° C. T (max) −T (start) ≦ 50 ° C. The maximum shrinkage dimensional change rate of this heat shrinkage rate curve is the maximum shrinkage rate [X ( max)], and the temperature at this time is the maximum shrinkage temperature [T (max)]. The shrinkage start temperature [T (start)] is
This is the temperature at the time of 1% shrinkage.

The heat-sensitive stencil film of the present invention must have a maximum shrinkage [X (max)] in at least one direction of at least 25%. Preferably it is 30 to 80%, more preferably 40 to 75%. More preferably, each of the ranges is in the above-described range in both the longitudinal direction and the width direction of the film. If the maximum shrinkage ratio is less than 25%, the perforation sensitivity becomes insufficient, a hole having a sufficient size is not formed, and the printed matter is blurred.

The shrinkage onset temperature [T (start)] of the film of the present invention must be 40 ° C. to 80 ° C., preferably 45 ° C. to 75 ° C., and more preferably 50 ° C. or more. 70 ° C. or less. If the shrinkage start temperature is less than 40 ° C., the dimensional stability of the product becomes poor, and the film may be deformed or wrinkled. On the other hand, if the temperature exceeds 80 ° C., the perforation becomes defective, and the printed matter may have white spots such as unperforated portions.

The difference between the maximum shrink temperature [T (max)] and the shrink start temperature [T (start)] of the film of the present invention is 50.
It must be below ° C. Preferably it is 45 ° C. or lower, more preferably 40 ° C. or lower. If the difference between the maximum shrinkage temperature and the shrinkage start temperature exceeds 50 ° C., holes of a sufficient size are not formed at the time of drilling with low energy, and the variation in the drilling diameter increases.

The heat-sensitive stencil film of the present invention needs to be a biaxially stretched film as described above. In an unstretched film, heat shrinkage is small and it melts at the time of perforation, but the hole is difficult to expand, so the perforation sensitivity becomes poor, and since the strength of the film is low, the film may be broken at the time of printing a large number of copies. .

The thickness of the film of the present invention is determined by the sensitivity required for the base paper, the perforation method used, the handleability of the film, and the like, but is preferably 0.2 to 8 μm, and more preferably 0 to 8 μm. 0.3 to 7 μm, more preferably 0.5 to 5 μm.

The heat-sensitive stencil printing film of the present invention is preferable because the effects of the present invention are more remarkably exhibited when the surface characteristics of the film, that is, the center line average roughness and the maximum roughness are within the ranges described below. .

That is, the central average roughness [Ra] of the film of the present invention is preferably in the range of 0.01 to 0.5 μm. Is more preferably 0.05 to 0.4 μm.

The maximum roughness [Rt] of the film of the present invention is:
The range is preferably 0.3 to 5 μm, and 0.5 to 4 μm from the viewpoint of film handling, productivity, and variation in perforation sensitivity.
μm is more preferred.

The crystal melting energy [ΔHu] of the film of the present invention is 20 to 60 J / g from the viewpoint that the dimensional change due to the change in temperature and humidity is small, and the handleability and low energy perforation are good. And more preferably 30 to 50 J / g.

Crystal melting temperature [Tm] of the film of the present invention
Is preferably 130 to 200 ° C., more preferably 13 to 200 ° C.
The temperature is 5 to 190C, more preferably 140 to 170C. Such a crystal melting temperature is preferably in the above-mentioned range because a melted portion serving as a starting point of perforation is easily formed and the perforation sensitivity is good, and further, the strength of the film is good. In addition, due to the composition of the film being a blend, etc., if a shoulder is present or a plurality of peaks are present, it is preferable that at least the shoulder or peak on the lowest temperature side is in the above range, and all the shoulders or More preferably, the peak satisfies the above range.

The glass transition temperature of the film of the present invention [T
g] is preferably from 50 to 85 ° C, more preferably from 55 to 85 ° C.
８０80 ° C. Such a glass transition temperature is preferably in the above range from the viewpoint of dimensional stability, perforation sensitivity and the like.

The polyester constituting the biaxially stretched polyester film of the present invention is a polymer comprising dicarboxylic acid component and glycol component, a polymer comprising hydroxycarboxylic acid component, or a copolymer thereof. As well as mixtures.

Examples of the dicarboxylic acid component constituting the polyester include terephthalic acid, isophthalic acid,
Phthalic acid, 2,6-naphthalenedicarboxylic acid, 1,4-
Naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 4,4'-diphenyldicarboxylic acid, 4,4'-
Aromatic dicarboxylic acid components such as diphenyl ether dicarboxylic acid, 4,4'-diphenyl sulfone dicarboxylic acid, and 5-sodium sulfoisophthalic acid; succinic acid, adipic acid, suberic acid, sebacic acid, dodecandioic acid;
An aliphatic dicarboxylic acid component such as dimer acid and eicosandioic acid, and an alicyclic dicarboxylic acid such as 1,4-cyclohexanedicarboxylic acid can be used.

As the glycol component, for example, ethylene glycol, 1,2-propylene glycol,
1,3-propylene glycol, 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.

The hydroxycarboxylic acid component includes, for example, glycolic acid, lactic acid, 3-hydroxybutyric acid,
4-hydroxybutyric acid, 3-hydroxyvaleric acid, 4-hydroxyvaleric acid, 6-hydroxycaproic acid and the like can be used.

Among such polyesters, among the polymers obtained by using the above-mentioned components, a polymer mainly composed of polylactic acid is more preferably used from the viewpoints of moldability, handleability, shrinkage characteristics, perforation sensitivity and the like of the film. Further, it may be a copolymer obtained using the above components, or may be a blend with a copolymer or the like. In the case of a copolymer, it may be a random copolymer or a block copolymer.

The heat-sensitive stencil master of the present invention is obtained by joining such a film and a porous support. The porous support is a porous material made of natural fibers, synthetic fibers, and the like, which can transmit the printing ink and does not substantially undergo thermal deformation under heating conditions under which the film is perforated. Non-woven fabric, woven fabric, gauze or other porous material.

The weight of the porous support is preferably from 1 to 20 g / m ² from the viewpoint of printability. More preferably ^{2 to} 16 g / m ² , still more preferably ^{2 to} 14 g / m ²
It is. The weight per unit area is preferably in the above range from the viewpoint of ink permeability, blurring of a printed image, ink retention, and image clarity.

The average diameter of the fibers constituting the porous support is preferably 0.5 to 20 μm, more preferably 1 to 15 μm, further preferably 1 to 10 μm, and particularly preferably 1 to 5 μm. The average diameter of the fibers is preferably in the above-mentioned range in view of the uniformity of ink transmission, the strength as a support, and the transportability of a master.

Further, all the fibers constituting the porous support may have the same diameter, or fibers having different fiber diameters may be mixed.

The film and master of the present invention can be produced by the following method using the above-mentioned polyester.

For example, in the case of a polymer mainly composed of polylactic acid, a raw material is mainly a lactic acid component of L-lactic acid or D-lactic acid, and a hydroxycarboxylic acid such as glycolic acid, hydroxybutyric acid, hydroxyvaleric acid or hydroxycaproic acid is used as a raw material. And directly subjecting the cyclic ester intermediate to ring-opening polymerization. For example, when produced by direct dehydration condensation, lactic acid or lactic acid and hydroxycarboxylic acids are preferably azeotropically dehydrated and condensed in the presence of an organic solvent, particularly a phenyl ether solvent, and particularly preferably a solvent distilled off by azeotropic distillation. The polymer having a high molecular weight suitable for the present invention can be obtained by performing polymerization by a method in which water is removed from the solvent and a substantially anhydrous solvent is returned to the reaction system.

Further, a cyclic ester intermediate such as lactide formed when a low molecular weight polymer is depolymerized at high temperature under reduced pressure is subjected to ring-opening polymerization under reduced pressure using a catalyst such as tin octylate to obtain a high molecular weight polymer. It is known that polymers can be obtained. The molecular weight of the polymer is preferably in the range of 10,000 to 1,000,000 from the viewpoint of moldability as a film. More preferably, it is 100,000 to 500,000. Also, if necessary, flame retardants, heat stabilizers, antioxidants, ultraviolet absorbers, antistatic agents, crystal nucleating agents, pigments, plasticizers, terminal blocking agents, organic lubricants such as fatty acid esters, waxes, or polysiloxanes And the like can be blended.

Further, lubricity can be imparted according to the purpose. The method of imparting lubricity is not particularly limited, but, for example, clay, mica, titanium oxide, calcium carbonate, calcium phosphate, kaolin, talc,
Examples include a method of blending inorganic particles such as alumina, zirconia, spinel, and wet or dry silica, organic particles having acrylic acid-based polymers, polystyrene, and the like as components, and a method of applying a surfactant. The amount of the particles to be blended is preferably 0.05 to 10 parts by weight, more preferably 0.1 to 3 parts by weight, based on 100 parts by weight of the polymer. The average diameter of the particles to be blended is 0.01 to 3
μm is preferred, and more preferably 0.1 to 2 μm. Such particles may be used in combination of plural kinds having different types and average diameters.

The film of the present invention can be obtained by biaxial stretching using the above-mentioned polymer. As the stretching method, inflation simultaneous biaxial stretching method, stenter simultaneous biaxial stretching method, is a biaxially stretched by any method of the stenter sequential biaxial stretching method, film forming stability,
From the viewpoint of thickness uniformity, a film formed by a stenter sequential biaxial stretching method is preferable.

The film of the present invention can be produced by using the above-mentioned polymer by the following method. After the polymer has been sufficiently dried, it is fed to an extruder for 15 minutes.
An unstretched film is obtained by melting at 0 to 250 ° C. and extruding onto a casting drum by a T-die extrusion method.

As a method of adhering to the casting drum, an electrostatic application method, an adhesion method utilizing surface tension of water or the like,
Any method such as an air knife method or a press roll method may be used.However, as a method for obtaining a film having good flatness and few surface defects, a contact casting method using surface tension of water or the like, or a static casting method. It is particularly preferred to use the electric charge application method. At this time, an unstretched film having a desired thickness can be produced by adjusting the slit width of the die, the discharge amount of the polymer used for the film, and the rotation speed of the casting drum. Next, a biaxially stretched film can be produced by simultaneously or sequentially biaxially stretching the unstretched film. In the case of sequential biaxial stretching, the stretching order may be such that the film is oriented in the longitudinal direction, the width direction, or vice versa. Further, in the sequential biaxial stretching, stretching in the longitudinal direction or the width direction can be performed twice or more. The stretching conditions of the film can be appropriately adjusted according to the desired heat shrinkage characteristics, orientation degree, strength, elastic modulus, etc. of the film, and can be carried out by any method.
The stretching temperature of the film is preferably lower than the glass transition temperature of the polymer used and not higher than the crystallization temperature, and more preferably the glass transition temperature of the polymer +20.
It is below ° C. Further, the preheating before stretching is preferably performed at a lower temperature equal to or lower than the stretching temperature of the film. The stretching ratio in the longitudinal direction and the width direction of the film can be set to any value in the range of 1.2 to 5.0 times that can set the stretching temperature lower, and is preferably 1.5 times or more. . Either the stretching ratio in the longitudinal direction or the stretching ratio in the width direction may be increased, and may be the same.

Further, after the film is biaxially stretched, a heat treatment may be performed for the purpose of improving and optimizing the strength, stability over time and shrinkage characteristics. This heat treatment can be performed by any method, such as in an oven or on a heated roll.
The heat treatment temperature is preferably lower than 30 ° C. and lower than the melting point, more preferably 100 ° C. or lower.
Also, the heat treatment time can be arbitrarily set,
It is preferably performed in a shorter time in the range of seconds, more preferably 30 seconds or less. The heat treatment may be performed while relaxing the film in the longitudinal direction and / or the width direction. The heat-treated film may be rapidly cooled to a glass transition temperature or lower after the heat treatment, or may be cooled stepwise.

In the film of the present invention, as a method for setting the heat shrinkage characteristic to a specific range, for example, a method of adjusting the composition, mixing ratio, mixing conditions, etc. of the raw material polymer, an extrusion temperature during film formation, a residence time, There are methods such as changing the preheating temperature, the stretching temperature, the speed, the magnification, the temperature of the heat treatment, the time, etc., and particularly using a polymer mainly composed of polylactic acid, lowering the stretching temperature, the heat treatment temperature, and shortening the heat treatment time. Adjusting the film to maintain a high orientation in the film is effective for improving the heat shrinkage property, and is preferable because the effects of the present invention are more remarkably exhibited.

The heat-sensitive stencil master of the present invention can be produced by bonding the above-mentioned film and a porous support.

The bonding between the film and the porous support may be performed by using an adhesive or the like, as long as the film does not hinder the perforation suitability of the film. The bonding method is more preferable because the transmission of the ink is not hindered by the adhesive or the like. More preferably, it is a method in which a non-woven fabric having a low orientation made of a thermoplastic resin is obtained by thermocompression bonding and co-stretching in a film manufacturing process. The unstretched film and the unstretched nonwoven fabric are stretched together in the thermocompression-bonded state, so that the nonwoven fabric serves as a reinforcing member, and has excellent curl resistance and printing durability. It is preferable because of extremely excellent film formation stability. The method of co-stretching is not particularly limited, and is preferably the same as a film stretching method such as a stenter sequential biaxial stretching method.

The film and master of the present invention are subjected to an aging treatment for the purpose of reducing deformation such as dimensional change and curl due to a change in temperature and humidity during storage in a manufacturing process or a long-term storage as long as the effects of the present invention are not impaired. May be applied. The processing conditions include a processing temperature of 30 to 80 ° C. and a processing temperature of 1 to 100.
It is preferable to apply for about an hour.

The fibers constituting the porous support may be subjected to a chemical treatment such as acid or alkali treatment, a corona treatment, a low-temperature plasma treatment or the like on the surface of the fibers, if necessary, in order to impart an affinity for the ink. Good.

In the master of the present invention, a release agent is preferably applied to the film surface in order to prevent fusion with a thermal head or the like. As the release agent, silicone oil, silicone-based resin, fluorine-based resin, surfactant, wax-based release agent and the like can be used. In these release agents, various additives can be used in combination as long as the effects of the present invention are not impaired. For example, antistatic agents, heat-resistant agents, antioxidants, organic particles, inorganic particles, pigments and the like can be mentioned. 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, gravure coater, reverse coater, bar coater or the like. Before the release agent is applied, the surface to be applied may be subjected to a corona discharge treatment in air or other various atmospheres, if necessary.

[0046]

The present invention will be described in more detail with reference to the following examples. The method for measuring the film properties in the examples is
It is as follows. (1) Film Thickness A film sample was arbitrarily selected at 10 points, cut out in a cross-sectional direction, photographed with an electron microscope at a magnification of 2000 times, and the film thickness was measured. This was performed for 10 photographs, and the average value was shown. (2) Thermal Shrinkage Characteristics of Film A film sample having a width of 4 mm and a measurement length of 10 mm was manufactured by Seiko Instruments Co., Ltd.
Using R6100, the temperature was measured at a rate of 10 ° C./min from 25 ° C. under a constant load of 0.5 g. The maximum shrinkage dimensional change rate of the obtained curve was defined as the maximum shrinkage rate, and the temperature at this time was defined as the maximum shrinkage temperature. The temperature at the time of 1% shrinkage was defined as the shrinkage start temperature. (3) Crystal melting peak temperature Differential scanning calorimeter RD manufactured by Seiko Instruments Inc.
Using a C220 model, 5 mg of a film sample was collected, and the minimum point of the endothermic curve obtained from the DSC curve measured at a rate of 20 ° C./min from room temperature in a nitrogen atmosphere was defined as the crystal melting peak temperature. When a plurality of endothermic curves were observed, the minimum point of each endothermic curve was defined as the crystal melting peak temperature. (4) Perforation characteristics The master produced was RISOGR manufactured by Riso Kagaku Kogyo Co., Ltd.
It was supplied to the APH "GR377", and a 5 mm square black solid plate was made into a grid by a thermal head plate making method (600 dpi). At this time, the energy applied to the thermal head was 17 μJ per dot. Perforation was performed in this state, and 100 perforated portions of the film were observed with a scanning microscope at a magnification of 200 times, and the area of the perforated portion of the film was measured. The average value and standard deviation of the perforated area per dot were obtained, and the perforation characteristics were evaluated by the following items. Both 感 度 and ○ are available for practical use in both sensitivity and variation.

A. Perforation sensitivity ：: The average perforation area is 450 μm ² or more.

：: average perforated area is 300 μm ² or more and 45
Less than 0 μm ² .

Δ: Average perforated area is 150 μm ² or more and 30
Less than 0 μm ² .

X: Those having an average perforated area of less than 150 μm ² .

B. Perforation variation Variation degree = 10 × log (average perforation area / standard deviation of perforation area) ² ◎: Variation degree of 15 or more ：: Variation degree of 10 or more and less than 15

Δ: The degree of variation is 5 or more and less than 10.

C: The degree of variation is less than 5. Example 1 Polylactic acid (weight average molecular weight 200,000, L-form: D-form ratio = 9)
9: 1) 0.5 parts by weight of calcium carbonate particles having an average particle size of 1.5 μm were added to 100 parts by weight, and after mixing, the mixture was supplied to a twin-screw extruder having a different rotation direction and extruded at 210 ° C. to be pelletized. The obtained pellet was treated at 100 ° C. under reduced pressure for crystallization and drying. Next, the pellets were supplied to an extruder having a screw diameter of 45 mm, and the temperature of the T die was 220 ° C.
And cast on a drum cooled to 25 ° C. with a diameter of 300 mm by electrostatic application to produce an unstretched film having a thickness of 16 μm. Next, after stretching in the longitudinal direction by 2.5 times between heating rolls at 70 ° C., it was sent to a tenter type stretching machine,
The film was stretched 3.2 times in the width direction at 75 ° C., and further heat-treated at 70 ° C. for 10 seconds in a tenter to produce a biaxially stretched film having a thickness of 2.0 μm. The crystal melting peak temperature of the film was 172 ° C. Table 1 shows the heat shrinkage characteristics of the obtained film.

Next, one side of the thus obtained film was adhered to a 10 g / m ² unit weight Japanese paper mainly composed of manila hemp using a vinyl acetate adhesive, and the other side of the film was coated with a silicone release agent. The mold was applied at 0.05 g / m ² using a bar coater to prepare a heat-sensitive stencil master. Table 1 shows the evaluation results of the heat-sensitive stencil master. Example 2 Polylactic acid (weight average molecular weight: 180,000, L-form: D-form ratio = 9)
4: 6) 0.5 parts by weight of calcium carbonate particles having an average particle size of 1.5 μm were added to 100 parts by weight, and after mixing, the mixture was supplied to a twin-screw extruder having a different rotation direction and extruded at 210 ° C. to form pellets. A biaxially stretched film having a thickness of 2.0 μm was prepared in the same manner as in Example 1 except that the pellets were crystallized and dried. The crystal melting peak temperature of the film is 16
7 ° C. Table 1 shows the heat shrinkage characteristics of this film.

Using a vinyl acetate adhesive on one side of the obtained film, a basis weight of 10 g / m ² containing Manila hemp as a main component
And then apply 0.05 g of a silicone release agent to the other side of the film using a bar coater.
/ M ² to prepare a heat-sensitive stencil master. Table 1 shows the evaluation results of the heat-sensitive stencil master. Comparative Example 1 Copolymerized polyester of ethylene terephthalate and ethylene isophthalate containing 0.5 parts by weight of calcium carbonate particles having an average particle size of 1.5 μm (copolymer molar ratio: 80/2)
0) was crystallized and dried under reduced pressure at 110 ° C. for 3 hours, then extruded at a T-die die temperature of 270 ° C. using an extruder having a screw diameter of 45 mm, and cast on a cooling drum having a diameter of 300 mm. A stretched film was produced. Next, after stretching 3.5 times in the longitudinal direction between heating rolls at 90 ° C., it is sent to a tenter type stretching machine, stretched 3.5 times in the width direction at 93 ° C., and further heat-treated at 80 ° C. in the tenter. A 2.0 μm thick film was produced. The crystal melting peak temperature of the film was 206 ° C. Table 1 shows the heat shrinkage characteristics of this film.

Using a vinyl acetate adhesive on one side of the obtained film, a basis weight of 10 g / m ² containing Manila hemp as a main component
And then apply 0.05 g of a silicone release agent to the other side of the film using a bar coater.
/ M ² to produce a heat-sensitive stencil master. Table 1 shows the evaluation results of the heat-sensitive stencil master. Comparative Example 2 Copolymerized polyester of ethylene terephthalate and ethylene naphthalate containing 0.5 parts by weight of calcium carbonate particles having an average particle size of 1.5 μm (copolymerization molar ratio 70/3)
0) was dried under reduced pressure at 80 ° C. for 3 hours, and then, using an extruder having a screw diameter of 45 mm, the T die die temperature was 270.
C. and extruded on a cooling drum having a diameter of 300 mm to produce an unstretched film. Next, after stretching 3.5 times in the longitudinal direction between the heating rolls at 105 ° C., it is sent to a tenter type stretching machine, stretched 3.5 times in the width direction at 110 ° C., and further heat-treated at 100 ° C. in the tenter. A 2.0 μm thick film was produced. The crystal melting peak temperature of this film was 192 ° C. Table 1 shows the heat shrinkage characteristics of this film.

Using a vinyl acetate-based adhesive on one side of the obtained film, a basis weight of 10 g / m ² containing Manila hemp as a main component
And then apply 0.05 g of a silicone release agent to the other side of the film using a bar coater.
/ M ² to prepare a heat-sensitive stencil master. Table 1 shows the evaluation results of the heat-sensitive stencil master. Example 3 A film having a thickness of 2.0 μm was produced in the same manner as in Example 1 except that the stretching temperature in the longitudinal direction and the stretching direction in the width direction were respectively set to 65 ° C. and 70 ° C. Table 1 shows the heat shrinkage characteristics of this film.

Using a vinyl acetate adhesive on one side of the resulting film, a basis weight of 10 g / m ² containing Manila hemp as a main component
And then apply 0.05 g of a silicone release agent to the other side of the film using a bar coater.
/ M ² to prepare a heat-sensitive stencil master. Table 1 shows the evaluation results of the heat-sensitive stencil master. Comparative Example 3 A film having a thickness of 2.0 μm was prepared in the same manner as in Example 1 except that the stretching ratio in the longitudinal direction and the width direction was set to 1.4 times and the stretching temperature was set to 85 ° C. Table 1 shows the heat shrinkage characteristics of this film.

Using a vinyl acetate adhesive on one side of the obtained film, a basis weight of 10 g / m ² containing Manila hemp as a main component
And then apply 0.05 g of a silicone release agent to the other side of the film using a bar coater.
/ M ² to prepare a heat-sensitive stencil master. Table 1 shows the evaluation results of the heat-sensitive stencil master. Example 4 90 parts by weight of the polylactic acid used in Example 1 and 10 parts by weight of a copolymer of poly-3-hydroxybutyric acid and poly3-hydroxyvaleric acid (copolymerization molar ratio 92/8) had an average particle size of 1.0 μm. After adding 0.3 parts by weight of calcium carbonate particles and mixing, the mixture was supplied to a twin-screw extruder and extruded at 210 ° C. into pellets. Using the obtained pellets, a film having a thickness of 2.0 μm was produced in the same manner as in Example 1 except that the stretching temperature in the longitudinal direction and the stretching direction in the width direction were respectively set to 60 ° C. and 65 ° C. The crystal melting peak temperature of the film was 170 ° C. Table 1 shows the heat shrinkage characteristics of this film.

Using a vinyl acetate adhesive on one side of the obtained film, a basis weight of 10 g / m ² containing Manila hemp as a main component
And then apply 0.05 g of a silicone release agent to the other side of the film using a bar coater.
/ M ² to prepare a heat-sensitive stencil master. Table 1 shows the evaluation results of the heat-sensitive stencil master. Example 5 Copolymerized polyester of ethylene terephthalate and ethylene isophthalate (copolymer molar ratio 80/20) at a die temperature of 290 ° C. and a discharge rate of 35 g / min using a rectangular spinneret having a hole diameter of 0.35 mm and 100 holes. ) Is spun by a melt blow method, and the fibers are collected on a conveyor.
Was calendered between metal rolls heated to produce an unstretched nonwoven fabric having a basis weight of 100 g / m ² .

Separately, the pellets used in Example 1 were
After drying under reduced pressure at a temperature of 3 ° C. for 3 hours, an extruder having a screw diameter of 45 mm was used and extruded at a T-die die temperature of 225 ° C., and cast on a cooling drum having a diameter of 300 mm to produce an unstretched film.

An unstretched nonwoven fabric was superimposed on the obtained unstretched film, supplied to a heating roll, and thermocompression-bonded at a roll temperature of 100 ° C. The thus obtained laminate is stretched 2.5 times in the length direction between heating rolls at 85 ° C., and then fed into a tenter-type stretching machine, stretched 3.0 times in the width direction at 87 ° C., and further in the tenter. A heat-sensitive stencil master having a thickness of 70 μm was prepared by heat treatment at 70 ° C. At the entrance of the tenter, a wax-based release agent was weighed at 0.1 g / m ² after drying using a gravure coater on the film surface of the master.
Applied. The fiber weight of the obtained master is 12 g / m.
^{2. The} average fiber diameter was 6 μm. The thickness of the film alone was 2.0 μm. Table 1 shows the heat shrinkage characteristics and the evaluation results.

[0063]

[Table 1]

As is clear from Table 1, Examples 1 to 5
Was constructed so that the heat shrinkage characteristics of the film fall within a specific range as shown in the above equation, so that an excellent film having high perforation sensitivity and small variation in perforation diameter was obtained. On the other hand, Comparative Examples 1 to 3 did not satisfy the above-mentioned formulas, so that the perforation sensitivity was insufficient and the variation in the perforation diameter was large.

[0065]

According to the present invention, the perforation at low energy is excellent, the energy supplied to the thermal head of the printing press can be reduced, the life of the thermal head can be reduced, the time required for plate making can be shortened, and the printed matter can be made finer. An excellent heat-sensitive stencil film that can be obtained can be provided.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) B29L 7:00 F term (Reference) 2H114 AB23 AB25 BA06 BA10 DA56 EA02 EA04 FA01 4F071 AA43 AA83 AB21 AE11 AF61 AH16 BB08 BC10 BC12 4F210 AA24 AG01 AG03 QA02 QA03 QC05 QC06 QD16 QG01 QG18 QW06 4J002 BC032 BG002 CF001 CF181 DE096 DE136 DE146 DE236 DH046 DJ016 DJ036 DJ046 DJ056 FA082 FD172 FD176 GQ00

Claims (6)

[Claims] 1. A biaxially stretched film made of polyester, which satisfies the following expression in a TMA heat shrinkage measurement (temperature rising rate: 10 ° C./min, 0.5 g constant load) of the biaxially stretched film. Characteristic heat-sensitive stencil film. X (max) ≧ 25% 40 ° C. ≦ T (start) ≦ 80 ° C. T (max) −T (start) ≦ 50 ° C. In the formula, X (max): maximum shrinkage [%] T (start): shrinkage start temperature [° C] T (max): Maximum shrinkage temperature [° C] 2. The heat-sensitive stencil film according to claim 1, wherein the biaxially stretched film has a crystal melting peak temperature of 130 ° C. to 200 ° C. 3. A biaxially stretched film having a thickness of 0.2 to 8
3. The heat-sensitive stencil film according to claim 1, wherein the thickness is μm. 4. 4. The heat-sensitive stencil printing film according to claim 1, wherein the biaxially stretched film is a film composed of a polyester mainly composed of polylactic acid. 5. A heat-sensitive stencil master comprising the heat-sensitive stencil film according to claim 1 and a porous support. 6. The heat-sensitive stencil printing master according to claim 5, wherein the bonding is in a form in which the bonding is performed substantially without an adhesive.