JPH09262959A - Thermosensitively perforative film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermosensitively pereforative film which is highly sensitive to perforation, excellent in dimensional stability over time free from the generation of creases during storage and is capable of forming a high quality print image on a printed matter without a peculiar vein of Japanese paper, if the film alone is used as a thermosensitive stencil. SOLUTION: This thermosensitively perforative film is a 5-15μm thick biaxially stretched film consisting of a thermoplastic resin composition of 80-98wt.% polyester resin and 2-20wt.% vinyl alcohol. In this case, the polyester resin is a mixture of a substantially amorphous polyester, a polyester with a melting point of 150-200 deg.C and a crystal fusion energy of 5-9cal/g, and a polyester with a melting point of 210-265 deg.C and a melt flow rate of 30-100g/10min.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat-sensitive perforating film which is used as an original plate for heat-sensitive stencil printing by performing digital plate making with a thermal head, for example.

[0002]

2. Description of the Related Art In recent years, much research has been conducted to use a thermoplastic resin film alone as a base paper for heat-sensitive stencil printing (hereinafter simply referred to as base paper). The purpose of these studies is to overcome the drawbacks of the base paper currently on the market, that is, the base paper in which an ultrathin thermoplastic resin film having a thickness of 2 μm or less and a porous support such as Japanese paper are laminated with an adhesive agent. As a measure against deterioration of image quality such as Japanese paper grain or white spots of printed matter caused by the adhered support hindering film perforation during plate making and the solid adhesive agent obstructing ink permeation during printing is there.

The most important issue in the development of a film-type base paper is to satisfy both the perforation sensitivity and the temporal stability of the heat-sensitive perforation film. A problem in the development of the film-only base paper is that it is necessary to increase the film thickness to impart rigidity such as mechanical strength and waist strength so that tearing or jamming does not occur during transportation in the printing machine. The thicker the film, the greater the thermal energy required for perforation and the less likely it is to perforate. On the other hand, it is generally known that a resin having a low glass transition point and a low melting point is used as a film base material in order to enhance the perforation sensitivity of a heat-sensitive perforated film having a large thickness. The film was deteriorated with time, for example, the orientation structure, which is a driving force for perforation, was relaxed during storage, the perforation sensitivity was lowered, and wrinkles due to shrinkage of the film were remarkable. Therefore, in order to increase the perforation sensitivity of the base paper, it is essential to increase the heat sensitivity of the film, but since this increase in heat sensitivity causes deterioration of the film over time, the perforation sensitivity and stability over time of contradictory properties are It was difficult to be compatible.

On the other hand, for example, Japanese Patent Application No. 6-21457.
No. 5 is composed of a composition comprising a substantially amorphous thermoplastic polyester resin and a crystalline thermoplastic polyester resin having a melting point of 150 to 200 ° C.
A heat-sensitive pierceable film having an oriented structure in which the maximum value of the heat shrinkage stress at 40 ° C. and the value of the stress retention rate are within a specific range is described. In this publication, since the thermal head contact portion of the film is heated with a wide temperature distribution from the resin melting temperature in the central portion to a relatively low temperature in the peripheral portion during perforation, in order to enhance the perforation sensitivity, perforation at the beginning of perforation is required. It is described that it is possible only when it has an oriented structure in which a heat shrinkage force for expanding a nucleus to a desired pore size is developed in a wide temperature range.

[0005]

However, the heat-sensitive perforable film described in the above-mentioned Japanese Patent Application No. 6-214575 focuses on preventing orientation relaxation during storage,
Although the reduction in perforation sensitivity was so small that it did not pose a problem, the dimensional stability over time was still insufficient, and wrinkles were generated due to the shrinkage of the film, which was a problem in practical use.

[0006] Further, the heat-sensitive stencil printing base paper products are usually distributed in a state in which a length of about 200 plates is wound in a roll shape, and they are transported from the manufacturer to the user or stored by the manufacturer or the user. In some cases, the ambient temperature may be raised to about 55 ° C. under severe conditions. Therefore, in a film-type base paper that is not laminated with a support, shrinkage is likely to occur during storage, and in a film that has a size shrinkage of 2% or more, wrinkles occur in the roll-shaped product, and the flatness of the base paper is impaired during plate making. There are problems such as poor contact with the thermal head, making it difficult to perforate, and transferring a wrinkle pattern to a printed matter.

Therefore, an object of the present invention is to prevent the occurrence of tears or jams during transportation in a printing machine when a heat-sensitive perforated film alone is used as a base paper for heat-sensitive stencil printing.
A heat-sensitive perforating film that has excellent perforation sensitivity, excellent dimensional stability over time, does not cause wrinkles during product storage, and that allows printed matter to have high quality printed images with no grain or white spots. To provide.

[0008]

Means for Solving the Problems The inventors of the present invention have conducted extensive studies to achieve the above object, and as a result, by mixing and using a vinyl alcohol polymer and a specific polyester,
The inventors have found that the dimensional stability with time and the shrinkability are improved, and arrived at the present invention. That is, the present invention is a biaxially stretched film having a thickness of 5 to 15 μm, which is composed of a thermoplastic resin composition composed of 80 to 98% by weight of a polyester resin and 2 to 20% by weight of a vinyl alcohol polymer,
The polyester resin is a substantially amorphous polyester (A), the melting point is 150 to 200 ° C., the crystalline melting energy is 5 to 9 cal / g, and the melting point is 210 to 265 ° C. Melt flow rate is 3
It is a heat-sensitive perforating film which is a mixture of polyester (C) of 0 to 100 g / 10 min.

Hereinafter, the present invention will be described in detail. The heat-sensitive perforable film of the present invention is different from the prior art in that it has a specific thermoplastic resin composition, that is, a substantially amorphous polyester (A), a low crystalline polyester (B), a melting point and a melt flow. A thermoplastic resin composition composed of a polyester resin, which is a mixture of polyester (C) having high properties, and a vinyl alcohol polymer is used as a base resin. The importance of such a difference is to provide a heat-sensitive perforating film which has high thermal sensitivity and has little dimensional shrinkage over time, thereby making it possible to improve the perforation sensitivity and the temporal stability of a film-type base paper, which has been difficult in the past. It is to enable both.

FIG. 1 is an experimental view showing the dimensional stability with time and the perforation sensitivity of the heat-sensitive perforable film of the present invention. That is, the elapsed time (hours) is plotted on the lower horizontal axis, the dimensional shrinkage ratio (%) is plotted on the left vertical axis, the film thickness (μm) is plotted on the upper horizontal axis, and the print density (OD value) is plotted on the right vertical axis. There is. The dimensional stability with time is indicated by circles (○ and ●) in FIG. 1 from the relationship between the elapsed time (lower horizontal axis) and the dimensional shrinkage ratio (left vertical axis). It can be read from the relationship between the film thickness (upper horizontal axis) and the print density (right vertical axis) indicated by ☆ and ★). However, the white marks (○ and ☆) in FIG. 1 indicate the case of the heat-sensitive perforating film of the present invention (corresponding to the experiment No. 1 described later), and the black marks (● and ★) indicate the conventional heat-sensitive perforating property. The case of a film is shown respectively. The dimensional shrinkage was measured in a state where the film could freely shrink in an atmosphere of 55 ° C.

The dimensional stability of the heat-sensitive perforable film over time is
As described above, the film-type base paper has a problem that wrinkles are generated in the roll-shaped product when the size shrinks by 2% or more in the atmosphere of 55 ° C. Therefore, the dimensional shrinkage ratio is preferably less than 2% so that wrinkles do not occur even in a 55 ° C. atmosphere that may be exposed during product storage. On the other hand, the perforation sensitivity is preferably such that the black solid print density (OD value) is 0.8 or more, and if it is lower than this, a considerable amount of white spots will be seen on a black solid print, and when printed, it will be blurred and difficult to read. .

Considering the result of FIG. 1 from the above viewpoint,
The heat-sensitive perforable film of the prior art has a dimensional shrinkage ratio of more than 2% after 6 hours in a 55 ° C. atmosphere, and thereafter, the dimensional shrinkage ratio increases with the elapse of time, reaching 4.5% after 24 hours. . Therefore, in the heat-sensitive perforable film of the prior art,
When used as a single film type base paper, dimensional shrinkage is remarkable and many wrinkles are generated, which is not practical.

On the other hand, the heat-sensitive perforable film of the present invention has a dimensional shrinkage of 0.8 after 6 hours in an atmosphere of 55 ° C.
It can be seen that it is saturated at%, and the dimensional stability over time is greatly improved. On the other hand, both the heat-sensitive perforated film of the present invention and the heat-sensitive perforated film of the prior art have a film thickness of 12 μm.
Even so, the print density exceeded OD = 1.0, and clear solid black prints were obtained. Even with a thickness of 15 μm, slight white spots were observed in the solid black prints, and both have sufficiently high perforation sensitivity. I understand. That is, the heat-sensitive perforable film of the present invention has significantly improved dimensional stability with time while maintaining the same perforation sensitivity as the heat-sensitive perforated film of the prior art, and has both perforation sensitivity and time-dependent dimensional stability. I understand.

The technical significance of using the above-mentioned specific thermoplastic resin composition as the base resin of the heat-sensitive perforable film in the present invention will be described below. The present inventor has found that the high crystalline resin having a high melting point can suppress the rapid orientation relaxation of the film in order to improve the dimensional stability with time, which has a high perforation sensitivity and cannot be solved in the above-mentioned Japanese Patent Application No. 6-214575. noticed. That is, a heat-sensitive perforable film is generally recognized that when a highly crystalline resin having a high melting point is used as a film base resin, thermal sensitivity is lowered and perforation sensitivity is also lowered. It has been found that the perforation sensitivity can be increased only when it exhibits the property. This, the process of perforating the film can be roughly divided into a "hole nucleation process" in which the film begins to be heated and starts to perforate, and a "hole expansion process" in which the perforation nuclei expand to a desired pore diameter by thermal contraction, This is because even if the high-melting-point highly crystalline resin has a fluidity at the time of melting within a specific range, perforation nuclei are easily formed.

Next, each of the resins constituting the above specific thermoplastic resin composition will be individually described. The role of the polyester (A) is to develop a heat shrinkage force at a relatively low temperature in the peripheral portion of the film contacting the thermal head. Therefore, it is important that the polyester (A) is substantially amorphous in order to make the thermal response of the film sharp. As used herein, “substantially amorphous” means DSC.
It means that no crystal melting peak is observed in the curve (rate of temperature rise / fall of 10 ° C./min, conforming to JIS K7121).
Further, the polyester (A) has a composition ratio of 50 to 80 in the polyester resin forming the heat-sensitive perforation film.
It is preferable to use in the range of wt%, and if carefully selected, it is 5
The range of 5 to 70% by weight is more preferable. The composition ratio is 5
When it is less than 0% by weight, the thermal response of the film becomes insensitive and the perforation sensitivity is lowered, and when it is more than 80% by weight, a sharp orientation relaxation occurs and the heat shrinkage force at a relatively high temperature near the contact center of the thermal head. Cannot be expressed.

The role of the polyester (B) is to suppress rapid orientation relaxation of the film and to develop a heat shrinkage force at a relatively high temperature near the contact center of the thermal head.
And to uniformly mix the polyester (A) and the polyester (C). Therefore, it is essential that the polyester (B) has crystallinity in order to maintain the oriented structure of the film, but it has a role as a compatibilizing agent for the amorphous polyester (A) and the high melting point polyester (C). Therefore, it is important that the melting point and crystal melting energy are low. The resin preferably has a melting point of 150 to 200 ° C. and a crystal melting energy of 5 to 9 cal / g, and when selected carefully, the melting point is 160 to 195 ° C.
And it is more preferable that the crystal melting energy is in the range of 6 to 8 cal / g. When the melting point of the resin is lower than 150 ° C. or when the crystal melting energy is lower than 5 cal / g, the orientation structure of the film cannot be maintained and the perforation sensitivity is lowered during storage, or the orientation is sharply relaxed during perforation. The heat shrinkage is insufficient and it becomes impossible to perforate.

On the other hand, when the melting point of the resin is higher than 200 ° C. or the crystal melting energy is higher than 9 cal / g, the thermal response of the film becomes insensitive and the perforation sensitivity is lowered. Further, the polyester (B) has a composition ratio of 10 to 10 in the polyester resin constituting the heat-sensitive perforable film.
It is preferably used in the range of 45% by weight, more preferably in the range of 15 to 35% by weight when carefully selected. When the composition ratio is less than 10% by weight, a rapid orientation relaxation occurs, or the polyester (A) and the polyester (C) cannot be uniformly mixed, and when it exceeds 45% by weight, the thermal response of the film becomes insensitive. The perforation sensitivity decreases.

The role of the polyester (C) is to maintain the orientation structure during storage and suppress the dimensional shrinkage of the film,
And to facilitate formation of perforation nuclei at the resin melting temperature at the center of the film contacting the thermal head. Therefore, it is important that the polyester (C) has a high melting point and high fluidity in the molten state. The resin has a melting point of 210 to 265 ° C. and a melt flow rate of 30 to
It is preferably in the range of 100 g / 10 minutes, more preferably a melting point of 220 to 255 ° C. and a melt flow rate of 50 to 90 g / 10 minutes when carefully selected. When the melting point of the resin is lower than 210 ° C., the oriented structure of the film cannot be retained and dimensional shrinkage occurs during storage,
If it is higher than 265 ° C, the thermal response of the film becomes insensitive and the perforation sensitivity is lowered.

On the other hand, the melt flow rate of the resin is 3
When it is lower than 0 g / 10 minutes, melt flowability is low and it becomes difficult to form perforation nuclei, and when it is higher than 100 g / 10 minutes, the thermoplastic resin composition cannot be uniformly mixed. Further, the polyester (C) is preferably used in a composition ratio of 5 to 40% by weight in the polyester resin constituting the heat-sensitive perforable film, and more preferably 15 to 35% by weight when selected carefully. When the composition ratio is less than 5% by weight, dimensional shrinkage occurs during storage, and when it is more than 40% by weight, the thermal response of the film becomes insensitive and the perforation sensitivity decreases.

Next, the role of the vinyl alcohol polymer among the resins constituting the above-mentioned specific thermoplastic resin composition will be described. The vinyl alcohol-based polymer here is, for example, an olefin-vinyl alcohol copolymer or a partially saponified product of polyvinyl acetate, which will be described in detail later. The use of a resin composition composed of 80 to 98% by weight of a polyester resin and 2 to 20% by weight of a vinyl alcohol polymer as a base resin for a heat-sensitive perforable film has already been disclosed in JP-A-5-185763. It is known.
According to the publication, the effect of using a vinyl alcohol-based polymer is that in a conventional base paper for laminating a support,
It is stated that by mixing a resin having good solvent resistance with a solvent such as toluene or ethyl acetate, softening of the film is prevented and unevenness of the support is not transferred.

However, the inventor of the present invention has found some novel effects which have not been obtained in the past when a vinyl alcohol polymer is used as a constituent resin of a film substrate. That is,
It was newly found that there is an effect of increasing the dimensional stability with time in a film-type base paper on which a support is not laminated. This is because the vinyl alcohol polymer has high crystallinity and can maintain the oriented structure of the film. Furthermore, it was newly found that the combination with a polyester resin has the effect of roughening the film surface. This is because the vinyl alcohol-based polymer has a suitable affinity for the polyester-based resin and thus is dispersed in a granular form with a particle size of about 1 to 5 μm, and the film surface is roughened.

Usually, a film used as a base paper has a surface roughened by adding inert inorganic fine particles in order to improve workability in a winding step during film production or to impart slipperiness with a thermal head during plate making. It was a face. In this case, in order to uniformly disperse the inert inorganic fine particles in the film base resin, it was necessary to perform a compounding process in which the particles were preliminarily melt-mixed before the film production process. However, in a thermoplastic resin composition comprising a polyester resin and a vinyl alcohol polymer, it is not necessary to add inert inorganic fine particles, and therefore, it is not necessary to perform compounding,
It has become possible to reduce film manufacturing costs.

In order to exhibit the above effects, the vinyl alcohol polymer is preferably used in a composition ratio of 2 to 20% by weight in the thermoplastic resin composition constituting the heat-sensitive piercing film, and is selected carefully. Then, the range of 2 to 15% by weight is more preferable. When the composition ratio is less than 2% by weight, the effect of retaining the oriented structure of the film becomes small, and when it is more than 20% by weight, uniform grain dispersion cannot be obtained, or the crystallinity becomes too high and the perforation sensitivity is increased. descend. In addition, the vinyl alcohol polymer preferably has a crystal melting energy in the range of 10 to 20 cal / g in order to maintain the film orientation structure to the extent that the perforation sensitivity is not deteriorated, and has a suitable affinity with the polyester resin. It is preferable that the proportion of vinyl alcohol units in the molecular structure is in the range of 50 to 90 mol% in order to provide the polymer with a melt flow rate of 0.5 to 0.5 in order to obtain an appropriate dispersed particle diameter in melt kneading during film production. It is preferably in the range of 15 g / 10 minutes.

The thermoplastic resin composition used in the present invention is composed of a polyester resin and a vinyl alcohol polymer, and the preferred monomer component of the polyester resin and the preferred repeating unit of the vinyl alcohol polymer are as follows. Are shown respectively. The monomer component of the polyester resin includes an acid component such as an aromatic dicarboxylic acid component such as a terephthalic acid component and an isophthalic acid component, an aliphatic dicarboxylic acid component such as an adipic acid component, and a 1,4-cyclohexanedicarboxylic acid component. 1 or 2 or more can be selected from the alicyclic dicarboxylic acid components, etc., and the alcohol component is an ethylene glycol derivative component such as an ethylene glycol component or a diethylene glycol component, or an alkylenediol component such as a 1,4-butanediol component. 1 or 2 from alicyclic diol components such as 1,4-cyclohexanedimethanol components
You can choose more than one. The term "monomer component" as used herein refers to the acid component and alcohol component of the repeating unit in the molecular structure of the polyester resin. Further, when one monomer component is selected for both the acid component and the alcohol component, the polyester resin is a homopolymer, and when two or more monomer components are selected for the acid component or the alcohol component, It shows that the polyester resin is a copolymer.

More preferably, as the polyester (A), the acid component is a terephthalic acid component, and the alcohol component is an ethylene glycol component of 60 to 80 mol% and 1,4-
Cyclohexanedimethanol component is 20-40 mol%
As a polyester (B), a terephthalic acid component is 50 to 85 mol%, an isophthalic acid component is 15 to 50 mol%, and an alcohol component is a 1,4-butanediol component. A resin is selected, and as the polyester (C), the acid component is a terephthalic acid component, the alcohol component is an ethylene glycol component,
Or a homopolymer composed of 1,4-butanediol component,
Alternatively, the acid component of the homopolymer is an isophthalic acid component of 10 m
A copolymer resin modified by not more than ol% will be selected.

On the other hand, the repeating unit of the vinyl alcohol-based polymer is, as described above, the proportion of the vinyl alcohol unit in the molecular structure is 50 to 90 mol% in order to exert the effects of dimensional stability of the film over time and surface roughening. It is preferably in the range of. As other repeating units in the molecular structure, olefin units such as ethylene units and propylene units, and other repeating units derived from monomers copolymerizable with vinyl acetate are selected. The vinyl alcohol unit is obtained by saponifying a vinyl acetate unit in the polymer molecular structure, and may include a non-saponified vinyl acetate unit. More preferably, an ethylene-vinyl alcohol copolymer or a partially saponified product of polyvinyl acetate will be selected.

The thermoplastic resin composition used in the heat-sensitive perforable film of the present invention is a composition obtained by melt-mixing these polyester resins and vinyl alcohol polymers. As a method of melt mixing, it may be preliminarily melt-mixed with a single-screw or twin-screw extruder, a Banbury mixer, a mixing roll, or the like, or may be premixed in a pellet state or a powder state with a blender or the like to produce a film. At this time, they may be melt-mixed in an extruder. However, it is desirable that the compounding process of preliminary melt mixing is not performed because it increases the manufacturing cost of the film.

When the heat-sensitive perforated film of the present invention is used as a base paper for perforation plate making with electromagnetic waves such as laser light, infrared rays and LED light, it is possible to disperse an electromagnetic wave absorbing substance which absorbs electromagnetic waves and generates heat. desirable. Examples of the electromagnetic wave absorbing substance include carbon, graphite, metal oxides, light absorbing metals, organic dyes, electromagnetic wave absorbing polymers and the like. Among these, carbon, graphite, black or dark pigments and metal oxides are more desirable because they have little wavelength dependence. On the other hand, phthalocyanine dyes, azo dyes, quinone dyes, and other substances that exhibit large absorption in a specific wavelength region can also be used effectively in some cases. These electromagnetic wave absorbing substances may be used alone or as a mixture of two or more kinds, and a substance having an absorption region corresponding to the wavelength of the electromagnetic wave used for perforation plate making is selected.

The heat-sensitive perforable film of the present invention can be produced by biaxially stretching the above-mentioned specific thermoplastic resin composition as a base resin. The manufacturing method of the film is
Sequential biaxial stretching method or simultaneous biaxial stretching method (tubular method, tenter method) or the like is performed. The stretching condition at that time is to stretch the film at a low temperature as much as possible in order to increase the heat shrinkage force of the film. Is desirable. Specifically, the heat shrinkage force of the film is such that the maximum value of the heat shrinkage stress at 70 ° C. is 50.
As shown in the range of 0 to 1000 g / mm ² ,
The stretching temperature is (Tg + 25) to (Tg + 45) ° C., and the stretching ratio is biaxial stretching in the area ratio of 15 to 35 times. In addition, Tg here represents the glass transition temperature (DSC method, JIS K7121 conformity) of a film base resin. More preferably, in order to carry out continuous stretching in a stable state, the heat-sensitive perforable film is stretched in multiple layers by providing a stretch-reinforcing layer that supports the stretching, rather than stretching it in a single layer. In this case, the layer structure is M / S, M / S, where M is the heat-sensitive perforation film layer and S is the stretch reinforcing layer.
S / M, S / M / S, M / S / M / S / M, S / M / S
/ M / S is preferable, and a layer structure of M / S / M is more preferable.

In the above-mentioned multi-layer stretching method, the stretching reinforcement layer has a Vicat softening point (VSP; ASTM D-1525).
Compliant, load 1 kg, heating rate 2 ° C / min) is mainly a thermoplastic resin having a temperature of 110 ° C or less, and a release agent (polyoxyethylene alkyl ether) for keeping good releasability from an adjacent heat-sensitive perforable film layer. And glycerin fatty acid ester or the like surfactant, dimethyl silicone oil, amino-modified or ether-modified modified silicone oil, fatty acid amide, etc.) are preferably contained.

The multilayer film produced by the above method can be further improved in stability over time by heat treatment or aging treatment. As the method of heat treatment, there are a method of pressing with a heating roll (embossing may be performed at the same time), a method of restraining or relaxing the film in a constant temperature oven, and any method may be used.
The heat treatment temperature is preferably in the range of (Tg-10) ° C to the stretching temperature, and the relaxation rate is 1 to 10 in both longitudinal and transverse directions.
It is desirable to carry out in the range of%. On the other hand, the aging method is 1 to 1 in a warm air thermostat set at 40 to 60 ° C.
It is desirable to store for 4 days.

The obtained multilayer film is directly subjected to secondary processing (eg, coating, surface treatment, laminating, etc.)
Or a single layer of the heat-sensitive perforated film that has been peeled off and used for secondary processing. The heat-sensitive perforable film of the present invention preferably has a thickness in the range of 5 to 15 μm, and more preferably 6 to 12 μm when carefully selected. When the thickness is less than 5 μm, the mechanical strength of the film is weak, which causes inconveniences such as tearing or jamming during conveyance in the printing machine, and wrinkles on the plate. On the other hand, when the thickness exceeds 15 μm, the perforation sensitivity is remarkably reduced.

When the heat-sensitive perforating film of the present invention is used as a base paper and perforated by a flash flash or a thermal head, the film surface in contact with the print original or the thermal head is fused with the print original or the thermal head. Surfactants (glycerin fatty acid ester, polyoxyethylene alkyl ether, alkylalkylolamine, etc.), fatty acid amide, fluororesin, silicone oil (desirably alkyl modified, amino modified, alcohol modified, etc.) to prevent sticking phenomenon It is desirable to form the layers in a thin layer. The method is not particularly limited, but may be coating, or by kneading and transferring the above substance into the resin for stretch-strengthening layer in the above-mentioned film manufacturing method.

The method of perforating a base paper using the heat-sensitive perforating film of the present invention is as follows: flash irradiation with a xenon flash lamp or the like, heating with a thermal head or the like, laser light (preferably semiconductor laser, YAG laser, etc.). Electromagnetic waves are radiated by an array that radiates infrared rays or LED light, and especially when a thermal head or laser light is used for digital perforation plate making, the printed matter becomes clearer.

[0035]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail with reference to Examples. Further, the resin used in the present invention, the method for measuring the physical properties of the film, the evaluation method / evaluation scale, the component ratio of the thermoplastic resin composition used, and the film extrusion molding apparatus / method are shown below. [Measurement Method of Physical Properties] (1) Film Thickness The film thickness t (μm) is the width W (cm) of the film,
The film was cut into a length L (cm), and the weight m (g) and the density ρ (g / cm ³ ) of the film sample were measured and calculated by the following formula. The density was measured at 23 ° C. by a density gradient tube method according to JIS K7112.

T = (m / (W · L · ρ)) × 10 ⁴ (2) DSC (differential scanning calorimeter) measurement melting point Tm (° C.), crystal melting energy ΔHm (cal /
g) and the glass transition temperature Tg (° C.) were measured by DSC (differential scanning calorimeter) according to JIS K7121. The measuring device is DSC-7 manufactured by PERKIN-ELMER.
Using (sample amount of 5 mg, calorific value calculated using indium as a standard substance), the temperature was held at 0 ° C. for 5 minutes, and then the temperature was raised to 300 ° C. at a heating rate of 10 ° C./minute for measurement. However,
The resin sample has a temperature of about 30 from the end temperature of the crystal melting peak.
After holding at ℃ high temperature for 10 minutes, temperature decrease rate 1 to 0 ℃
The sample was cooled at 0 ° C./minute and then used for measurement.

(3) Melt flow rate Melt flow rate MFR (g / 10 minutes) is defined by JIS
It measured based on K7210. The measurement conditions were as follows: the test load was 2160 g, and the test temperature was 10 ° C. higher than the melting point in DSC measurement (Tm + 10) ° C. (4) Heat shrinkage stress Width 20 mm in each of the longitudinal direction and the lateral direction of the film,
A film sample cut into a length of 100 mm was set on a pair of chucks equipped with a strain gauge on one chuck so that the chuck distance was 50 mm and the initial load was 2 g. It is immersed in a silicone oil thermostat heated to a predetermined temperature, and the generated contraction force is measured by a storage recorder (Memory Hicoder 88 manufactured by Hioki Electric Co., Ltd.).
15).

The maximum value of the heat shrinkage stress is determined by the obtained time-
The maximum value within 10 seconds after dipping was divided by the film cross-sectional area (thickness × width) from the graph of shrinkage force, and the value was obtained and shown as the average value in the machine direction and the transverse direction of the film. Here, if the graph of time-contraction force shows the maximum of the contraction force within 10 seconds after the immersion, the maximum value is obtained, and if it does not show the maximum until 10 seconds after the immersion and continues to increase, the immersion time is 10 seconds later. The value of was taken as the maximum value of the contraction force and used in the calculation. The time axis of the storage recorder was set in the range of 20 msec / DIV to 2 sec / DIV so that the maximum value of the contraction force appears in the range of 1 to 5 DIV after immersion.

[Evaluation Method / Evaluation Scale] (1) Dimensional stability over time A film sample cut into a square with a side of 100 mm was left in a warm air thermostat set at 55 ° C. in a freely shrinkable state. The amount of shrinkage of the sample after 24 hours was measured and divided by the original size to obtain a percentage. The obtained value of dimensional shrinkage was used as an index of dimensional stability over time. The dimensional shrinkage ratio is shown as an average value in the machine direction and the transverse direction of the film.

<Evaluation Scale> Dimensional shrinkage (%) Judgment Remarks Less than 1% ◎ Small dimensional shrinkage and no wrinkles 1% or more and less than 2% ○ Slight dimensional shrinkage but almost no wrinkles 2% or more 4 Less than% △ Dimensional shrinkage is large and wrinkles are considerably generated 4% or more × Dimensional shrinkage is considerably large and wrinkles are significantly generated (2) Perforation sensitivity A sample film with a predetermined thickness and a polyester fiber having a wire diameter of 40 μm with a woven density of 270 mesh are used. Woven thickness 64μ
M woven cloth is bonded to only four sides (the bonding is not on the entire surface but the film and mesh woven cloth are overlapped at the plate making part), and is not in contact with the mesh cloth of the film Amino-modified silicone oil (KF864 manufactured by Shin-Etsu Chemical Co., Ltd.) was coated on the surface at 10 mg / mm ² to prepare a heat-sensitive stencil printing base paper. As a plate-making device, a printing device TH-PDM manufactured by Okura Electric Co., Ltd., and a line-type thermal head TPH293R9 manufactured by Toshiba (heating element density 16 dot /
mm) is used, and the plate-making pattern is all solid,
The base paper was perforated for plate making with a plate making energy of 80 μJ / dot.

Only the plate-making portion of the base paper is cut off and the mesh-like woven cloth is peeled off to prepare a plate-made film, which is a commercially available master RC.
Only the four sides were attached to the hollowed-out portion of M56W and fixed to obtain an original plate. This original plate is a lithograph RC manufactured by Ideal Science Co.
It was mounted on a printing drum No. 335, and only printing operation was performed under normal printing conditions to print 30 sheets. The print density (OD value) of the 25th print was measured with a handy type reflection densitometer DM-800 manufactured by Dainippon Screen Mfg. Co., Ltd. The obtained print density value was used as an index of perforation sensitivity.

<Evaluation Scale> Print Density (OD Value) Judgment Remark 1.00 or more ◎ Black solid of printed matter is clear 0.85 or more and less than 1.00 ○ Black solid of printed matter has almost no white spot 0.70 or more Less than 0.85 △ Black solid of printed matter has many white spots <0.70 × Black solid of printed matter is remarkable (3) Orientation retention value Heat shrinkage stress immersion at 140 ° C Value after 5 seconds (α) The maximum value of the heat shrinkage stress (β) at 140 ° C. and 140 ° C. was measured according to the method for measuring the heat shrinkage stress, and the ratio (α / β) between them was determined. The value of the obtained stress retention rate was used as an index of orientation retention.

<Evaluation scale> Stress retention rate Judgment Remark 0.20 or more ◎ No effect on perforation sensitivity 0.15 or more and less than 0.20 ○ Almost no effect on perforation sensitivity 0.10 or more and less than 0.15 △ There is an influence on perforation sensitivity less than 0.10 × remarkably large influence on perforation sensitivity (4) Extrusion uniformity According to the film manufacturing method of the example described later, an extruding apparatus is used to produce a raw material before stretching. Obtained. The surface condition of the obtained raw fabric, the presence or absence of flow unevenness and thickness unevenness, etc. were observed and evaluated, and used as an index of extrusion uniformity. The base resin of the heat-sensitive perforable film was premixed in a pellet state by a blender and then melt-mixed in an extruder of an extrusion molding device.

<Evaluation Scale> Observation Evaluation Judgment Remarks The surface is smooth and has no thickness unevenness. ◎ Stable stretching is possible. The surface is smooth and there is almost no thickness unevenness. ○ Stretching is possible. Flow is uneven and the surface is rough. △ Stable Cannot be stretched. Flow unevenness is severe and the surface is extremely rough. X Stretching is not possible. (5) Transport and plateability Amino-modified silicone oil on one side (KF manufactured by Shin-Etsu Chemical Co., Ltd.
864) 10 mg / mm ² coated roll-shaped sample film with a width of 320 mm is used as a lithograph R manufactured by Ideal Science Co.
The C335 base paper storage unit was set so that the surface coated with silicone oil was in contact with the line type thermal head of the plate making unit. Facsimile test chart No. A plate-making operation was performed in a photo mode under normal plate-making conditions using 1WP as a document. Occurrence of film breakage in this case,
The occurrence of jams and the like in the transport path, the occurrence of wrinkles at the time of plate deposition, the possibility of plate ejection, etc. were observed and evaluated, and used as an index of transport plateability.

<Evaluation Scale> Observation Evaluation Judgment: No problem at all ◎ Wrinkles are slightly generated at the time of printing, but there is no problem in printing ○ Wrinkles are included at the time of printing, which affects the printed product △ Cuts, jams, etc. Inability to plate on x [Component ratio of thermoplastic resin composition used] In the examples and comparative examples of the present invention, the thermoplastic resin composition used as the base material of the heat-sensitive perforation film has a plurality of constituent resins. Was pre-mixed in the form of pellets using a blender and then melt-mixed in an extruder at the time of film production.

First, Table 1 shows the contents of the polyester resin which is a constituent resin of the thermoplastic resin composition used in Examples and Comparative Examples of the present invention. Table 1 shows the monomer components of polyester (A), polyester (B) and polyester (C), their component ratios, and the physical property values of these resins. Here, TPA is a terephthalic acid component, I
PA is an isophthalic acid component, NDA is a 2,6-naphthalenedicarboxylic acid component, EG is an ethylene glycol component, B
D is a 1,4-butanediol component, HMD is a 1,6-hexamethylenediol component, CDM is a 1,4-cyclohexanedimethanol component, Tg (° C) is a glass transition temperature, Tm (° C) is a melting point, and ΔHm ( cal / g) is a crystal melting energy, and MFR (g / 10) is an abbreviation for melt flow rate.

[0047]

[Table 1]

[Film Extrusion Equipment / Method] Next,
An outline of an extrusion molding apparatus and an extrusion molding method at the time of manufacturing a film for melt-mixing premixed constituent resins will be shown. Caliber 40m
m, L / D = 38 extruder (I), caliber 32 mm, L /
A circular die for co-extruding the molten resin in a three-layer state is provided at the tips of the three extruders of the extruder (II) and the extruder (III) in which D = 40, from the extruder (II) to the outermost layer, the extruder ( A device was used in which the molten resin was connected so as to flow from I) to the intermediate layer and from the extruder (III) to the innermost layer. The resin composition (S) for stretch-strengthening layer was premixed in the extruder (I), and the base resin (M) for heat-sensitive perforable film premixed had a water content of 50.
Extruder (II) after sufficiently drying to below ppm
And an extruder (III), and coextruded into a three-layer state of M / S / M, cooled with water, and folded to obtain a take-up raw material.

Here, the above-mentioned resin composition (S) for stretch-reinforcing layer was equipped with an injection pump capable of injecting a liquid substance into the mixing portion under pressure, and a strand die having three extrusion openings with a diameter of 5 mm was attached to the tip. Caliber 45mm, L / D =
Using the extruder of No. 44, the three kinds of resins shown in Table 2 were pre-mixed in a pellet state by using a blender and then fed to the extruder to obtain the additive obtained by mixing the two kinds of oily substances shown in Table 2. What was melt-mixed while injecting and extrusion-granulated from a strand die was used.

In Table 2, MI (g / 10 minutes)
Is the MFR at a measurement temperature of 190 ° C. and a load of 2160 g.

[0051]

[Table 2]

[0052]

Example 1 and Comparative Example 1 This experiment is an experiment focusing on the values of the melting point and the crystal melting energy of the polyester (B). Therefore, as the resin constituting the thermoplastic resin composition, the same resin was used as the resin other than the polyester (B), and the composition ratio thereof was constant. Further, at the time of producing the film, the stretching condition is that the stretched film has a maximum value of heat shrinkage stress at 70 ° C. of 580 to 630 g / mm.
We are trying to keep it within the range of ² , heat treatment conditions and aging treatment conditions are constant, and the thickness of the heat-sensitive perforation film is 8 μm.
And

The base resin (M) for heat-sensitive perforating film contains 60% by weight of A1 resin as polyester (A),
95% by weight of a polyester resin comprising 20% by weight of a B1 resin as a polyester (B) and 20% by weight of a C1 resin as a polyester (C), and a vinyl alcohol polymer having a vinyl alcohol unit ratio of 5 in the molecular structure.
6mol%, crystal melting energy 12.5cal /
g, 5% by weight of ethylene-vinyl alcohol copolymer having a melt flow rate of 3.5 g / 10 min was used to obtain an M / S / M three-layer stock according to the above-mentioned extrusion molding method. . The original fabric is heated again by the heating furnace of the stretching machine,
The film was biaxially stretched 5.0 times in the longitudinal direction and 5.5 times in the lateral direction at an ambient temperature of 87 ° C., then cooled with cold air, folded, and taken up. The folded film was wound using a heating roll as it was while heat-treating at a heat treatment temperature of 50 ° C., a relaxation rate of 2% (average value in the machine direction and the transverse direction), and a heat treatment time of 5 seconds. The rolled film roll is 4
The sample was stored in a warm air constant temperature bath set at 5 ° C. for 5 days for aging treatment. Thereafter, the film in a three-layer state was peeled into each layer to obtain a heat-sensitive perforated film having a thickness of 8 μm. The obtained film was subjected to Experiment No. Let it be 1.

Then, B2 resin was used as the polyester (B), and the stretching atmosphere temperature was changed to 85 ° C. except that the above experiment No. The same experiment as in No. 1 was repeated, and the obtained film was tested as Experiment No. 1. Let it be 2. The above Experiment No. was used except that B3 resin was used as the polyester (B) and the drawing atmosphere temperature was changed to 90 ° C. The same experiment as in No. 1 was repeated, and the obtained film was tested as Experiment No. 1. 3 is assumed. In the above Experiment No. except that B4 resin was used as the polyester (B) and the stretching atmosphere temperature was changed to 83 ° C. The same experiment as in No. 1 was repeated, and the obtained film was tested as Experiment No. 1. 4 is assumed. The above experiment N except that B5 resin was used as the polyester (B) and the stretching atmosphere temperature was changed to 91 ° C.
o. The same experiment as in No. 1 was repeated, and the obtained film was tested as Experiment No. 1. 5 is assumed. B6 resin was used as the polyester (B) and the stretching atmosphere temperature was changed to 80 ° C. The same experiment as in No. 1 was repeated, and the obtained film was tested as Experiment No. 1. 6 is assumed. B7 resin was used as the polyester (B), and the stretching atmosphere temperature was changed to 96 ° C. The same experiment as in No. 1 was repeated, and the obtained film was tested as Experiment No. 1. 7 is assumed.

In this experiment no. Using the heat-sensitive perforable films 1 to 7 as sample films, the above-mentioned orientation retention and perforation sensitivity were evaluated. They are summarized in Table 3
Shown in According to the results of Table 3, the melting point of the polyester (B) is 150 to 200 ° C. and the crystal melting energy is 5 to 9
Those having a cal / g range have a high stress retention rate of heat shrinkage stress at 140 ° C. and have a high perforation sensitivity without abruptly relaxing the oriented structure of the film at the time of perforation (Experiment Nos. 1 and 2). 3, 4). On the contrary,
It is understood that the polyester (B) having a melting point of more than 200 ° C. and a crystal melting energy of more than 9 cal / g has a marked black spot in the black solid print and has a low perforation sensitivity (see Experiment No. 5). If the melting point and / or crystal melting energy of the polyester (B) is less than the above range, the stress retention rate is low, the oriented structure of the film is suddenly relaxed during perforation, and the heat shrinkage force is insufficient. It can be seen that the perforation sensitivity is low (see Experiment Nos. 6 and 7).

[0056]

[Table 3]

[0057]

Example 2 and Comparative Example 2 This experiment focuses on the melting point value of the polyester (C). Therefore,
The resin constituting the thermoplastic resin composition is the same as the resin other than the polyester (C) and the composition ratio is constant, and the melt flow rate of the polyester (C) is 85 to 90 g / 10 min. I used the one in the range.
Further, at the time of producing the film, the stretching condition is that the stretched film has a maximum value of heat shrinkage at 70 ° C. of 580 to 630.
Yes strive to be in the range of g / mm ^2, heat treatment conditions and aging treatment conditions constant, the thickness of the heat-sensitive perforating film was 8 [mu] m.

In addition to using the C2 resin as the polyester (C) and changing the stretching atmosphere temperature to 95.degree. The same experiment as in No. 1 was repeated, and the obtained film was tested as Experiment No. 1. 8 is assumed. C as polyester (C)
Experiment No. 3 except that the stretching atmosphere temperature was changed to 86 ° C. by using 3 resin. The same experiment as in No. 1 was repeated, and the obtained film was tested as Experiment No. 1. 9 is assumed. C4 resin is used as polyester (C), and the drawing atmosphere temperature is 10
Other than changing to 0 ° C., the above experiment No. The same experiment as in No. 1 was repeated, and the obtained film was tested as Experiment No. 1. It is assumed to be 10. C5 resin was used as the polyester (C), and the stretching atmosphere temperature was changed to 85 ° C.
o. The same experiment as in No. 1 was repeated, and the obtained film was tested as Experiment No. 1. 11

This experiment No. 1, Experiment No. Using the heat-sensitive perforable films of Nos. 8 to 11 as sample films, the above-described dimensional stability with time and perforation sensitivity were evaluated.
They are collectively shown in Table 4. According to the results of Table 4, when the melting point of the polyester (C) is in the range of 210 to 265 ° C., the printing density is at a practical level (OD value of 0.
It shows that the perforation sensitivity is high and the dimensional stability with time is excellent (see Experiment Nos. 1, 8 and 9). On the other hand, the melting point of polyester (C) is 26
It is found that those having a melting point of more than 5 ° C have low perforation sensitivity (see Experiment No. 10), and those having a melting point of polyester (C) less than 210 ° C have considerably large dimensional shrinkage and poor dimensional stability with time (Experiment No. 10). 11).

[0060]

[Table 4]

[0061]

Example 3 and Comparative Example 3 This experiment is an experiment focusing on the value of the melt flow rate (MFR) of the polyester (C). Therefore, the resin constituting the thermoplastic resin composition is the same as the resin other than the polyester (C), and the composition ratio is kept constant.
Has a melting point of 225 ° C. At the time of manufacturing the film, the stretching conditions are such that the stretched film has a maximum value of heat shrinkage at 70 ° C. within a range of 580 to 630 g / mm ² , and the heat treatment condition and the aging treatment condition are constant, and the heat-sensitive piercing property is high. The thickness of the film was 8 μm.

In addition to using the C7 resin as the polyester (C) and changing the stretching atmosphere temperature to 88 ° C., the above experiment No. The same experiment as in No. 1 was repeated, and the obtained film was tested as Experiment No. 1. It is assumed to be 12. In addition to using the C8 resin as the polyester (C) and changing the stretching atmosphere temperature to 88 ° C., the above experiment No. Repeat the same experiment as 1.
The obtained film was subjected to Experiment No. It is assumed to be 13. Using the C6 resin as the polyester (C), the above experiment No. When extrusion molding was performed in the same manner as in No. 1, the raw fabric had severe flow unevenness, and stretching was impossible. This experiment is referred to as Experiment No. 14
And C9 resin is used as polyester (C),
Other than changing the drawing atmosphere temperature to 90 ° C., the above experiment No. The same experiment as in No. 1 was repeated, and the obtained film was tested as Experiment No. 1. Set to 15.

This experiment No. 1, Experiment No. 12-15
The above-mentioned extrusion uniformity was evaluated by using the original fabric as a sample. In addition, the heat-sensitive perforation film obtained in these experiments was used as a sample film to evaluate the perforation sensitivity described above. They are collectively shown in Table 5.
In addition, experiment No. In No. 14, since a heat-sensitive perforation film was not obtained, the perforation sensitivity was not evaluated and the judgment was "-". According to the results shown in Table 5, when the melt flow rate of the polyester (C) is in the range of 30 to 100 g / 10 min, the printing density is at a practical level (OD value 0.85).
The above shows that the perforation sensitivity is high (Experiment No.
1, 12, 13). On the other hand, when the melt flow rate of the polyester (C) exceeds 100 g / 10 min, the flow unevenness of the raw fabric is so severe that uniform melt mixing cannot be performed (see Experiment No. 14), and the melt of the polyester (C) is It can be seen that when the flow rate is less than 30 g / 10 minutes, the black solid printed matter has a marked white spot and the perforation sensitivity is low (see Experiment No. 15).

[0064]

[Table 5]

[0065]

Example 4 and Comparative Example 4 This experiment is an experiment focusing on the composition ratio of polyester (A), polyester (B) and polyester (C). Therefore, the resin constituting the thermoplastic resin composition has the same composition ratio as that of the polyester resin and vinyl alcohol polymer except that the composition ratio of these polyester resins is changed. At the time of producing the film, the stretching conditions are such that the maximum value of the heat shrinkage stress of the stretched film at 70 ° C. is in the range of 580 to 630 g / mm ² , and the heat treatment conditions and the aging treatment conditions are constant, and the heat-sensitive perforation is performed. The thickness of the flexible film was 8 μm.

Table 6 shows the contents of the thermoplastic resin compositions used in Example 4 and Comparative Example 4. Composition number 1 in Table 6
Is the above experiment No. 1 shows the thermoplastic resin composition used in Example 1. The composition No. 2 was used as the thermoplastic resin composition and the stretching atmosphere temperature was changed to 91.degree. The same experiment as in No. 1 was repeated, and the obtained film was tested as Experiment No. 1. It is assumed to be 16. The above experiment No. 1 was used except that the composition number 3 was used as the thermoplastic resin composition. The same experiment as in No. 1 was repeated, and the obtained film was tested as Experiment No. 1. 17
And The composition No. 4 was used as the thermoplastic resin composition and the stretching atmosphere temperature was changed to 86 ° C. The same experiment as in No. 1 was repeated, and the obtained film was tested as Experiment No. 1. It is assumed to be 18. The above Experiment No. was used except that Composition No. 5 was used as the thermoplastic resin composition and the drawing atmosphere temperature was changed to 99 ° C. Repeat the same experiment as 1.
The obtained film was subjected to Experiment No. 19 is assumed. The composition No. 6 was used as the thermoplastic resin composition and the stretching atmosphere temperature was changed to 86.degree. The same experiment as in No. 1 was repeated, and the obtained film was tested as Experiment No. 1. 20. The composition of Experiment No. 7 was used, except that Composition No. 7 was used as the thermoplastic resin composition and the stretching atmosphere temperature was changed to 83 ° C. The same experiment as in No. 1 was repeated, and the obtained film was tested as Experiment No. 1. 21. The composition No. 8 was used as the thermoplastic resin composition and the stretching atmosphere temperature was changed to 98 ° C. Repeat the same experiment as 1.
The obtained film was subjected to Experiment No. 22. The composition No. 9 was used as the thermoplastic resin composition and the stretching atmosphere temperature was changed to 89.degree. The same experiment as in No. 1 was repeated, and the obtained film was tested as Experiment No. 1. 23. The above experiment No. was used except that composition No. 10 was used as the thermoplastic resin composition and the stretching atmosphere temperature was changed to 85 ° C. The same experiment as in No. 1 was repeated, and the obtained film was tested as Experiment No. 1. 24. Using the composition No. 11 as the thermoplastic resin composition, the above experiment No. When extrusion molding was performed in the same manner as in No. 1, the raw fabric had severe flow unevenness, and stretching was impossible. This experiment is referred to as Experiment No. 25.

This experiment No. 1, Experiment No. 16-25
The above-mentioned extrusion uniformity was evaluated by using the original fabric as a sample. Further, the heat-sensitive perforated film obtained in these experiments was used as a sample film, and the above-mentioned orientation retention, dimensional stability with time and perforation sensitivity were evaluated. The results are shown in Table 7. In addition, experiment No. 25
Since a heat-sensitive perforation film was not obtained in the above, the degree of orientation retention, dimensional stability over time, and perforation sensitivity were not evaluated and the judgment was "-". According to the results of Table 7, the polyester-based resin constituting the thermoplastic resin composition of the substrate for heat-sensitive perforable film contains 50 to 80% by weight of polyester (A), 10 to 45% by weight of polyester (B), and polyester. The mixture of (C) in the range of 5 to 40% by weight shows a practical print level (OD value of 0.85 or more), high perforation sensitivity, and excellent dimensional stability over time. It turns out (Experiment No. 1, 16, 17, 18, 19,
20, 21). On the other hand, polyester (A)
In the case where the composition ratio of the polyester resin exceeds 80% by weight or less than 50% by weight, the black solid print has white spots and the perforation sensitivity is low (see Experiment Nos. 22 and 24). ). Also, polyester (C)
If the composition ratio of the polyester resin is less than 5% by weight of the polyester resin, the dimensional shrinkage is considerably large and the dimensional stability with time is poor (see Experiment No. 23), and the composition ratio of the polyester (B) is 10% of the polyester resin. It can be seen that if the content is less than 10% by weight, the flow ununiformity of the raw fabric is so severe that uniform melting and mixing cannot be achieved (see Experiment No. 25).

[0068]

[Table 6]

[0069]

[Table 7]

[0070]

Example 5 and Comparative Example 5 This experiment focuses on the composition ratio of the vinyl alcohol polymer. Therefore, the resin constituting the thermoplastic resin composition is the type of polyester resin, polyester (A), polyester (B) and polyester of the polyester resins, except that the composition ratio of the vinyl alcohol polymer is changed. The composition ratio of (C) and the type of vinyl alcohol-based polymer were the same. At the time of producing the film, the stretching conditions are such that the maximum value of the heat shrinkage stress of the stretched film at 70 ° C. is in the range of 580 to 630 g / mm ² , and the heat treatment conditions and the aging treatment conditions are constant, and the heat-sensitive perforation is performed. The thickness of the flexible film was 8 μm.

The above experiment No. 1 was used except that a thermoplastic resin composition composed of 2% by weight of a vinyl alcohol polymer and 98% by weight of a polyester resin was used and the stretching atmosphere temperature was changed to 86 ° C. The same experiment as in No. 1 was repeated, and the obtained film was tested as Experiment No. 1. 26. The above experiment No. was used except that a thermoplastic resin composition composed of 15% by weight of a vinyl alcohol polymer and 85% by weight of a polyester resin was used, and the stretching atmosphere temperature was changed to 89 ° C. The same experiment as in No. 1 was repeated, and the obtained film was tested as Experiment No. 1. 27
And The above experiment No. 1 was repeated except that a thermoplastic resin composition composed of 20% by weight of a vinyl alcohol polymer and 80% by weight of a polyester resin was used and the stretching atmosphere temperature was changed to 90 ° C. The same experiment as in No. 1 was repeated, and the obtained film was tested as Experiment No. 1. 28. In the above experiment No. 1 except that a thermoplastic resin composition composed of 1% by weight of a vinyl alcohol polymer and 99% by weight of a polyester resin was used, and the stretching atmosphere temperature was changed to 86 ° C. The same experiment as in No. 1 was repeated, and the obtained film was tested as Experiment No. 1. 29. The experiment No. was the same as the experiment No. 1 except that a thermoplastic resin composition composed of 23% by weight of a vinyl alcohol polymer and 77% by weight of a polyester resin was used and the drawing atmosphere temperature was changed to 90 ° C. The same experiment as in No. 1 was repeated, and the obtained film was tested as Experiment No. 1. Set to 30.

This experiment No. 1, Experiment No. 26-30
Using the heat-sensitive perforable film as a sample, the above-described dimensional stability with time and perforation sensitivity were evaluated. They are collectively shown in Table 8. According to the results shown in Table 8, when the composition ratio of the vinyl alcohol polymer is in the range of 2 to 20% by weight, the printing density shows a practical level (OD value of 0.85 or more) and the perforation sensitivity is high. It is found that it is high and has excellent dimensional stability over time (Experiment No. 1, 26,
27, 28). On the other hand, when the composition ratio of the vinyl alcohol polymer is less than 2% by weight, the dimensional shrinkage is large and the dimensional stability with time is poor (see Experiment No. 29), and the composition ratio of the vinyl alcohol polymer is 20%. It can be seen that black solid prints with more than 10% by weight have a lot of voids and low perforation sensitivity (see Experiment No. 30). Experiment N
o. In Experiment No. 29, wrinkles were generated in the winding step during the film production due to the poor slipperiness of the heat-sensitive perforable film. In No. 30, since the heat-sensitive perforated film slipped too much, the film meandered in the winding step during the film production and the end faces were not aligned.

[0073]

[Table 8]

[0074]

Example 6 and Comparative Example 6 This experiment is an experiment focusing on the film thickness of the heat-sensitive perforation film. Therefore, the resin constituting the thermoplastic resin composition has the same composition ratio. At the time of film production, the stretching conditions were such that the maximum value of the heat shrinkage stress of the stretched film at 70 ° C. was in the range of 580 to 630 g / mm ² , and the heat treatment conditions and the aging conditions were constant.

The above experiment No. was changed except that the film thickness was changed to 6.0 μm. The film obtained by repeating the same experiment as that of Experiment 1 was used as Experiment No. 1. 31. Stretching atmosphere temperature is 8
Other than changing the film thickness to 12.0 μm at 8 ° C., the above experiment No. The film obtained by repeating the same experiment as that of Experiment 1 was used as Experiment No. 1. 32. Film thickness is 5.0μ
m except that the above experiment No. was changed. The film obtained by repeating the same experiment as that of Experiment 1 was used as Experiment No. 1. 33. Other than changing the stretching atmosphere temperature to 89 ° C. and the film thickness to 15.0 μm, the above Experiment No. The film obtained by repeating the same experiment as that of Experiment 1 was used as Experiment No. 1. 34. Other than changing the stretching atmosphere temperature to 86 ° C. and the film thickness to 4.5 μm, the above experiment No. The film obtained by repeating the same experiment as that of Experiment 1 was used as Experiment No. 1. 35. Other than changing the stretching atmosphere temperature to 89 ° C. and the film thickness to 16.0 μm, the above Experiment No. The film obtained by repeating the same experiment as that of Experiment 1 was used as Experiment No. 1. 36.

This experiment No. 1, Experiment No. 31-36
Using the heat-sensitive perforable film as a sample film, the above-described perforation sensitivity and transport plateability were evaluated. They are collectively shown in Table 9. The results shown in Table 9 show that the film having a film thickness of 5 to 15 μm does not cause film breakage or jam in the printing machine and has a high perforation sensitivity (Experiment No. 1, 31, 32, 33, 34). reference).
On the other hand, if the film thickness is less than 5 μm, jamming or the like occurs and printing cannot be performed (Experiment N
o. 35), a film having a film thickness of more than 15 μm has many white spots on the black solid printed matter, and the perforation sensitivity decreases (see Experiment No. 36).

[0077]

[Table 9]

[0078]

[Reference Example] This experiment was conducted to examine that the change in dimensional shrinkage of a heat-sensitive perforated film over time and the change in perforation sensitivity depending on the film thickness differ depending on the thermoplastic resin composition used as the substrate. Is an experiment. Therefore,
When producing the film, the stretching condition is 7 for the stretched film.
The maximum value of heat shrinkage stress at 0 ° C is 580 to 630 g.
We tried to keep it within the range of / mm ² , and kept the heat treatment conditions and aging conditions constant.

Composition No. 1 was used as the thermoplastic resin composition, the drawing atmosphere temperature was 86 to 89 ° C., and the film thickness was 5, 6, 7, 8, 9, 10, 12, 15 μm. The above experiment No. The same experiment as 1 was repeated to obtain the heat-sensitive perforable film of the present invention. The thermoplastic resin composition comprises 99% by weight of a polyester resin and 1% by weight of a vinyl alcohol polymer, the polyester resin is 55% by weight of A1 resin and 45% by weight of B1 resin, and the vinyl alcohol resin is ethylene- Other than using a mixture that is a vinyl alcohol copolymer (vinyl alcohol unit ratio 56 mol%), the stretching atmosphere temperature is 81 to 85 ° C., and the film thickness is 5, 6, 8, 10, 12, 15, 16 μm. Is the above experiment No. The same experiment as in 1 was repeated to obtain a conventional heat-sensitive perforable film.

Of these heat-sensitive perforable films, those having a film thickness of 8 μm were used as sample films, and the elapsed time was 3, 6, 12, 2 according to the above-mentioned evaluation of dimensional stability with time.
The dimensional shrinkage ratio was measured after 4, 36 and 48 hours. Also,
The print density of the black solid printed matter was measured according to the evaluation of the perforation sensitivity described above using the heat-sensitive perforation film having each film thickness as a sample film. The results are summarized in FIG.

In FIG. 1, the lower horizontal axis represents elapsed time (hours) and the left vertical axis represents dimensional shrinkage (%), and the circles (○ and ●) indicate how the dimensional shrinkage increases with time. ). On the other hand, the film thickness (μm) is plotted on the upper horizontal axis and the print density (OD value) is scaled on the right vertical axis. Stars (☆ and ★) indicate how the print density decreases as the film becomes thicker. . However, the white marks (∘ and ∘) in FIG. 1 indicate the case of the heat-sensitive perforated film of the present invention, and the black marks (● and ★) indicate the case of the conventional heat-sensitive perforated film.

According to the results shown in FIG. 1, the heat-sensitive perforated film of the prior art has a dimensional shrinkage ratio of more than 2% after 6 hours in an atmosphere of 55 ° C., and thereafter, the dimensional shrinkage ratio increases with time. It reached 4.5% after hours. Therefore, in the heat-sensitive perforable film of the prior art, when it is used as a single film type base paper, the dimensional shrinkage is remarkable and many wrinkles occur, which is not practical. On the other hand, it can be seen that the heat-sensitive perforable film of the present invention saturates at a dimensional shrinkage rate of 0.8% after 6 hours in an atmosphere of 55 ° C., and the dimensional stability with time is significantly improved. On the other hand, the heat-sensitive perforable film of the present invention,
With the heat-sensitive perforating film of the prior art, even if the film thickness is 12 μm, the printing density exceeds OD = 1.0, and clear black solid printing is obtained. Even with a thickness of 15 μm, some white spots are seen in black solid printing. It can be seen that both are sufficiently high in perforation sensitivity. That is, the heat-sensitive perforable film of the present invention has significantly improved dimensional stability with time while maintaining the same perforation sensitivity as the heat-sensitive perforated film of the prior art, and has both perforation sensitivity and time-dependent dimensional stability. I understand.

Although not shown in FIG. 1, the thermoplastic resin composition is composed of 95% by weight of a polyester resin and 5% by weight of a vinyl alcohol polymer, the polyester resin being an A1 resin and a vinyl alcohol. The above experiment No. 1 was used except that a mixture in which the resin was an ethylene-vinyl alcohol copolymer (vinyl alcohol unit ratio 56 mol%), the stretching atmosphere temperature was 100 ° C., and the film thickness was 8 μm. The heat-sensitive perforation film of the prior art obtained by repeating the same experiment as in 1 was evaluated as perforation sensitivity as a sample film, and the printing density of the black solid print was OD value 0.51. Was significantly lower.

[0084]

EFFECTS OF THE INVENTION According to the present invention, when a heat-sensitive perforated film alone is used as a base paper for heat-sensitive stencil printing, there is no occurrence of tears or jams during transportation in a printing machine, excellent perforation sensitivity, and dimensional stability over time. It is possible to provide a heat-sensitive perforating film which does not cause wrinkles or the like during storage of the product and can obtain a high-quality printed image without printed lines or white spots on printed matter.

[Brief description of drawings]

FIG. 1 is an experimental diagram showing changes in dimensional shrinkage over time and changes in perforation sensitivity depending on film thickness for each of the heat-sensitive perforable films of the present invention and the prior art.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location B29K 67:00

Claims (3)

[Claims] 1. A biaxially stretched film having a thickness of 5 to 15 μm, which is composed of a thermoplastic resin composition composed of 80 to 98% by weight of a polyester resin and 2 to 20% by weight of a vinyl alcohol polymer. Polyester resin is substantially amorphous polyester (A), melting point 150-200
A mixture of polyester (B) having a crystal melting energy of 5 to 9 cal / g and a melting point of 210 to 265 ° C. and a melt flow rate of 30 to 100 g / 10 min. Characteristic heat-sensitive perforating film. 2. The polyester resin comprises 50 to 80% by weight of polyester (A) and 10 of polyester (B).
~ 45% by weight, and 5-40% of the polyester (C)
The heat-sensitive pierceable film according to claim 1, wherein the heat-sensitive pierceable film is a mixture by weight. 3. The vinyl alcohol polymer, wherein the proportion of vinyl alcohol units in the molecular structure is 50 to 90 mol%,
The heat-sensitive perforable film according to claim 1 or 2, wherein the crystal melting energy is 10 to 20 cal / g and the melt flow rate is 0.5 to 15 g / 10 minutes.