JPH0761160A - Thermal punchable film and perforated stencil making method - Google Patents

Abstract

PURPOSE:To simplify and reduce a cost of a stencil by forming a thermal punchable film of a biaxially oriented film made of thermoplastic resin and having a specific thickness and setting a maximum value of heating shrinkage stress, heating shrinkage factor, an elongation load and a centerline mean roughness. CONSTITUTION:A thermal punchable film is formed of a biaxially oriented film formed of thermoplastic resin and having a thickness of 4-12mum. A maximum value of a heating shrinkage stress at 45-150 deg.C is set to 300-1500g/mm<2>, a heating shrinkage factor at 150 deg.C is set at least to 30%, a 2% elongation load is set at least to 100g/cm width, and a centerline mean roughness (Ra) is set to 0.02-0.40mum. On the other hand, the film is held between a line type thermal head for generating heat to 200-500 deg.C and a platen roll for 0.01-0.5msec, and independent pores are continuously formed. In this case, a platen roll having recesses and protrusions arranged regularly is used or an endless belt having recesses and protrusions arranged regularly is held at the roll side.

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 effective in reducing the running cost of printing, and a perforating plate-making method for the film.

[0002]

2. Description of the Related Art A conventional base paper for printing is a polyester film or polypropylene film having a thickness of about 2 μm.
A laminate of a thermoplastic resin film such as vinyl chloride film or vinyl chloride-vinylidene chloride film (hereinafter referred to as heat sensitive film) and a porous support such as Japanese paper or gauze (hereinafter referred to as support) Was used.

In order to improve the thermal response of the heat-sensitive film, a low crystalline resin made of a copolymer is used, and a thin film is used. Therefore, the film is not stiff, and as a countermeasure against this, the film is laminated with a support so as to have transportability in a printing machine and printing durability during printing.

[0004]

DISCLOSURE OF THE INVENTION The present invention is capable of plate-making independently by applying a film to a fully automatic plate-making / printing machine without using a support, and in a transport system, particularly in plate-receiving / plate-discharging. An object of the present invention is to provide a heat-sensitive perforated film that solves the problem, and to provide a perforated plate-making method capable of excellent plate making without film shrinkage even in the case of film making, especially in the case of photographic originals.

[0005]

The present invention is a biaxially stretched film made of a thermoplastic resin and having a thickness of 4 to 12 μm, and the maximum value of the heat shrinkage stress at 45 to 150 ° C. is 3.
0 to 1500 g / mm ² , heat shrinkage at 150 ° C. of at least 30%, 2% elongation load of at least 10
0 g / cm width, center line average roughness (Ra) is 0.02
It is a heat-sensitive perforable film having a thickness of 0.40 μm.

Another aspect of the present invention is to use a heat-sensitive perforating film in an amount of 200 to 50 for 0.01 to 0.5 msec.
A punching method for forming continuous independent holes by sandwiching between a line type thermal head that generates heat at 0 ° C and a platen roll, using a platen roll having regularly arranged irregularities, or a heat-sensitive punching property. 2. The method for perforating a film according to claim 1, wherein an endless belt having regular irregularities is sandwiched on the platen roll side of the film.

Since the film of the present invention is perforated plate-making without using a support, the film thickness is thicker than the conventional heat-sensitive perforating film. On the other hand, by making the film thicker, the film characteristics that could not be considered in the past are perforation characteristics,
Became important. The thickness of the film of the present invention is 4 to 12 μm.
m, preferably 5 to 10 μm. If the thickness is less than 4 μm, problems such as tearing in a plate making / printing machine and winding on a roll are likely to occur. When the film thickness becomes thicker than this,
The resin melted at the time of perforation solidifies and bulges around the holes, but this tends to become an ink reservoir and the density tends to be uniform regardless of the number of printed sheets. In addition, there was a tendency to prevent the phenomenon that the ink spreads between the printing paper and the film due to the capillary phenomenon and the printed matter bleeds. When it is thicker than 12 μm, it is quite difficult to perforate with a thermal head (hereinafter referred to as TH) even with a film having a heat shrinkage property described later. For example, a polyester film is placed on a plate making machine, and TH is exothermicly heated to 300 ° C. in 0.3 msec (this condition is assumed to be a normal plate making condition of a commercially available plate making machine) to make the film TH. When the temperature of the surface not in contact (called the back surface temperature) is measured, it is about 295 ° C. when the film thickness is 2 μm and about 240 ° C. when the film thickness is 5 μm.
At 2 μm, it drops to about 160 ° C. In order to perforate plate making under these conditions, at least a melting point or a similar temperature (perforating temperature) of a film having a thickness of 12 μm must be 160 ° C. or lower (the melting point must be further lowered to obtain a practical level). However, if the thermal conductivity is improved with carbon, metal powder or the like, the back surface temperature is improved, but it is considerably difficult to raise the temperature by about 50 ° C. at a practical level. Also, if the TH surface temperature is raised, the back surface temperature rises, but considering the life of TH, the limit is 300 ° C plus 100 ° C (here, even if the TH surface temperature is raised by 100 ° C,
The film backside temperature rises only about 50 ° C). In order to perforate at a low temperature as described above, thermal responsiveness at a low temperature is required, which is not preferable because of the problem of dimensional stability.

The film of the present invention is biaxially stretched,
The maximum value of heat shrinkage stress at 45 to 150 ° C is 300.
˜1500 g / mm ² and a heat shrinkage at 150 ° C. of at least 30%. Since the film thickness is thicker than the conventional film, a better thermal response is required. The temperature at which the maximum value of heat shrinkage stress appears is given as a measure of thermal response. The lower the expression temperature, the better the thermal response.
Practically, when the temperature is lower than 45 ° C., dimensional stability and shrinkage during plate making occur. When it is higher than 150 ° C., the thermal response is low, and the perforation sensitivity is remarkably low in a film having a thickness of 4 μm or more. Preferably 50-
The temperature is 130 ° C, more preferably 60 to 120 ° C.

In the film of the present invention, 45 to 150
Maximum value of heat shrinkage stress at 300 ℃ is 1500-1500g
/ Mm ² is necessary, and preferably 350 to
1200 g / mm ² , more preferably 400-1000
It is g / mm ² . More preferably, it has a maximum value of two or more peaks in the temperature dependence of the heat shrinkage stress.
However, even in this case, the maximum value is in the temperature range of 60 to 120 ° C. Maximum heat shrinkage stress is 300g /
If the thickness is less than mm ² , even if the film responds to heat, a thick film having a thickness of 4 to 12 μm does not effectively expand the holes because the force for expanding the holes is small. On the other hand, if it exceeds 1500 g / mm ² , the mechanical strength of the film decreases.

Further, the heat shrinkage percentage at 150 ° C. is at least 30%, preferably 35 to 90%, more preferably 40 to 80%. If it is less than 30%, the pores cannot be effectively expanded even if the heat shrinkage stress is large. When plate-making a heat-sensitive perforated film without using a support, a 2% elongation load of the film is important in order to reduce image distortion and troubles in the transport system. The film of the present invention has a value of at least 10
The width is 0 g / cm width, preferably 200 g / cm width or more, and more preferably 300 g / cm width or more.

The center line average roughness (R
a) is 0.02-0.40 μm, preferably 0.02-
It is 0.20 μm. If Ra is less than 0.02, troubles such as clogging in the conveying system and winding around a roll may occur, and problems such as close contact with TH during plate making may occur. R
As a increases, an air layer becomes thicker between TH and the film, and it becomes difficult for the heat of TH to be effectively transferred to the film. In particular, for a film having a thickness of 4 μm or more, the perforation energy must be used effectively as much as possible. According to the results of research conducted by the present inventors, when the air layer is 1 μm, a difference of about 10 ° C. occurs between the temperature of the TH surface and the temperature of the film surface. In the case of the line type TH, the surface temperature variation between each heat generation pair is approximately 5 ° C. or less, and therefore, Ra needs to be 0.40 or less in consideration of this.

Even when Ra is in the above range, if the large protrusions are present and the maximum roughness (Rmax) is large, unperforated portions are likely to occur around the large protrusions, so Rmax is preferably small. Rmax is preferably 3 μm or less, more preferably 2 μm or less. In order to obtain the above-mentioned roughness, inorganic particles, organic particles and the like may be added during the polymerization of the resin or during the film production process, but the latter is preferable. Also, a method of blending incompatible resins having different viscosities can be mentioned.

As the thermoplastic resin constituting the heat-sensitive perforable film of the present invention, polyester resin, polyamide resin, vinyl chloride resin, polycarbonate resin,
Examples include polyolefin resins and vinyl chloride resins. Polyester resin is preferable. As the acid component of the polyester resin, for example, terephthalic acid and its isomers (isophthalic acid, phthalic acid), their derivatives,
One or more selected from aliphatic dicarboxylic acids such as naphthalenedicarboic acid or a derivative thereof, adipic acid and succinic acid, and a derivative thereof; as an alcohol component, for example, ethylene glycol, a derivative thereof (diethylene glycol, triethylene glycol) , Polyethylene glycol, etc.), alkylene glycols (trimethylene glycol, tetramethylene glycol, hexamethylene glycol, neopentyl glycol, etc.), saturated aliphatic cyclic glycols (cyclohexanediol, cyclohexanedimethanol, cyclohexanealkyldiols, etc.), It is a polyester obtained by copolymerizing one or more diols having an aromatic ring such as a bisphenol nucleus. A preferred combination is terephthalic acid (40 mol% or less of isophthalic acid, phthalic acid,
Adipic acid or the like may be copolymerized. ). Further, as the alcohol component, ethylene glycol, diethylene glycol, butanediol, cyclohexanedimethanol, neopentyl glycol, bisphenol A, etc. are freely polymerized, and a mixture of components is prepared by polymerization.

In particular, it is preferable to use a copolymerized and substantially amorphous resin because the perforation sensitivity is high. For example, when the terephthalate component of polyethylene terephthalate (PET) is replaced with isophthalate (IPA component), I
The PA component is preferably about 20 to 80 mol%. Further, when the terephthalate component of polybutylene terephthalate (PBT) is replaced with isophthalate (IPA component), the IPA component is preferably about 20 to 80 mol%. In terms of perforation sensitivity, PBT modified with isophthalate is preferable because it is higher than PET modified with isophthalate.

Further, in the case of copolymerization, it is preferable to lower the crystallization rate to substantially amorphize rather than lower the melting point. As described later, when the melting point is lowered, the glass transition point (T
Since g) also decreases, there is a problem in dimensional stability. For example,
When PET is modified with 1,4-cyclohexanedimethanol, the glass transition point hardly changes, but the crystallization rate slows down to become substantially amorphous.

In addition to the above resins, other polyester resins (for example, copolymerized polyester resins having a lowered melting point as described above), polyolefins (ethylene polymers, ethylene-vinyl alcohol copolymers, propylene polymers, etc.) A thermoplastic resin such as a polyamide or a cellulosic resin may be blended at 40% by weight or less. In this case, D
What has two or more melting peaks measured by the SC method (heating rate 10 ° C./min) is preferable from the viewpoint of dimensional stability and prevention of disordered expansion of pores.

Inorganic particles such as silica, carbon, calcium carbonate, mica, talc, etc., resin, such as styrene-based or acrylic cross-linked resin particles, resin particles such as silicone resin particles, hollow particles, metal powders such as copper, zinc and titanium , And pigments, dyes, antistatic agents, surfactants and the like may be added for the purpose of reducing solvent attack, imparting slipperiness, improving perforation sensitivity, and preventing static electricity.

Examples of the method for obtaining the film of the present invention include a tubular method and a tenter method (simultaneous biaxial stretching, sequential biaxial stretching, etc.). An area magnification of (Tg) to (Tg + 45 ° C.) of the resin constituting the film, more preferably (Tg + 15 ° C.) to (Tg + 30 ° C.), preferably 4 to 50 times, more preferably 9 to 35 times. It is a method of simultaneously stretching in the biaxial direction. Further, in order to effectively impart a shrinkage component at a low temperature, it is preferable to provide a layer that supports stretching (hereinafter referred to as a reinforcing layer) and perform stretching in a multi-layer form. The layer constitution at that time is M / when the heat-sensitive perforation film layer is M and the reinforcing layer (may be a multilayer) is B.
B, M / B / M, B / M / B, M / B / M / B / M ...
・ ・ Can be indicated by. When B is selectively subjected to a crosslinking treatment, the latitude of stretching is widened, which is preferable. The film stretched by the above method is heat-treated if necessary.

The heat-sensitive film may have one layer, two layers, or three layers.
It may have a multi-layered structure of more than one layer. In that case, it is necessary that at least one surface layer is the film described in the present invention. Perforation performance may be improved by adding inorganic or organic particles to one layer and not adding the other layer, or by reducing the addition amount. In order to prevent the film surface from sticking with TH, for example, a fatty acid amide, a surfactant (monoglycerin
Ester, di-glycerin mono-ester, polyoxyethylene alkyl ether, alkyl alkylol amine, etc.), fluororesin, silicone oil (preferably alkyl-modified, amino-modified, mercapto-modified,
Modified silicone oil such as epoxy-modified or alcohol-modified) or the like, or in the above-mentioned method for producing a film, kneading the above substance into another reinforcing layer and transferring it to the surface of the film. May be formed. This layer is more preferably a layer containing amino-modified silicone oil as a constituent component and further containing an antistatic agent, a lubricant and the like. The amount of this layer is preferably 0.001-0.1 g
/ M ² , and if it is less than this amount, sticking occurs, and if it is more than this, perforation is hindered. Also, the film surface and TH
If a liquid is present between the surface and the surface, TH easily adheres to the film surface and the perforation sensitivity increases.

In order to perforate the above-mentioned heat-sensitive film, the film is subjected to 200 to 0.01-0.5 mesc.
The plate is continuously punched by being sandwiched between a line type thermal head that generates heat at ˜500 ° C. and a platen roll. 0.01
When the plate-making is used at a temperature of less than msec or more than 500 ° C., TH, particularly the current value flowing between the heating element and the electrode is too high, and the life of TH is shortened. Further, the stick phenomenon becomes remarkable between the heat-sensitive film and TH. However, there are the following problems even when the perforation plate making is performed under the above conditions.

First, when the pressing pressure of the platen roll is increased, the air layer between the film and TH is thinned and the perforation start energy of the film is lowered, but the pores become small or become unperforated. . This is because the platen roll is a rubber roll having a smooth surface and is in close contact with the heat-sensitive film to prevent perforation. Therefore, it is preferable that the platen roll and the heat-sensitive film do not adhere to each other.

On the other hand, if there are many perforated portions as in a photo original, the thermal energy during plate making is accumulated in the peripheral portion of the TH heating element, and even if no energy is applied, the thermal energy of the peripheral portion of the TH can be raised to about 50 to 100 ° C. The temperature rises. Therefore, since the heat-sensitive film in contact with TH shrinks, it is necessary to prevent shrinkage on the platen roll or to provide other shrinkage prevention means in order to prevent shrinkage.

In order to solve these problems, it is necessary to use a platen roll having regular unevenness or to punch and plate an endless belt having regular unevenness. If the irregularities are not regular, the image will be distorted. Further, if the arrangement of the irregularities is regular, even if the perforations of the film are obstructed by the convex portions, the printed matter is less affected. When the platen roll is provided with regular irregularities, the area ratio of the convex portions is preferably 1 to 40%. If it is less than 1%, the ability to hold the film is insufficient, deformation and tear of the film, defective perforation (decreased sensitivity) due to the movement of the film, etc. may occur, or the holes may expand to connect with the adjacent holes and become independent holes. Tend to be difficult to form. When the area ratio of the convex portions is larger than 40%, the tendency of hindering the perforation of the film increases, and the image quality of the printed matter tends to deteriorate. The area ratio is more preferably 1 to 35%,
More preferably, it is 1 to 30%.

The height difference between the convex portion and the concave portion is at least 15 μm
Is preferred. If it is less than 15 μm, it tends to adhere to the film due to deformation due to pressing and hinder perforation easily. The height difference is more preferably 15 to 500 μm, further preferably 25 to 400 μm. The shape of the upper end of the convex portion is not particularly limited, but in the case of an independent convex portion, a round shape, an elliptical shape, a gourd shape, a triangle, a quadrangle (square, rhombus, rectangle,
Etc.), polygons (hexagons, etc.), etc. In addition, in the case of continuous convex parts, mesh shape (when intersecting at a right angle, when intersecting at an angle, any one may be used), wavy shape, blind shape, etc. Is mentioned.

In the case of independent convex portions, the size of the upper end of each convex portion is preferably 1 × 10 ^{−4 to} 6.4 ×.
It is 10 ^-3 mm ² . If it is smaller than 1 × 10 ⁻⁴ mm ² ,
5. The ability to hold the film tends to be insufficient, and
If it is larger than 4 × 10 ⁻³ mm ^{2, the} perforability of the film tends to be impaired. In case of continuous convex part, its width is 5
To 100 μm is preferable, and more preferably 10 to 80 μm.
m. If the width is narrower than 5 μm, the ability to hold the film tends to be insufficient, and if it is wider than 100 μm, the perforability of the film tends to be impaired.

Even if the platen roll surface is not provided with irregularities, it is also effective to carry out perforation plate making while conveying an endless belt having regular irregularities from the platen roll side while superposing it on the heat-sensitive perforable film and carrying it. The regular unevenness in the case of the endless belt may be formed by forming unevenness such as the platen roll or using a porous body.

In the case of the porous body, the ratio of the area of the opening portion to the area of the heat-sensitive perforating film in contact with the plate making portion is 60 to 99%, and the opening area is 100 to 20.
The thickness of 00 μm ² / piece is preferable from the viewpoint of the perforability of the film and prevention of distortion. From the viewpoint of strength, the endless belt preferably has a thickness of 5 μm or more, more preferably 10 μm or more.

The platen roll and the endless belt are preferably made of a material having a low thermal conductivity (0.5 W / m · K or less). Examples of the manufacturing method of the roll and the endless belt include an embossing method, a photoresist (positive and negative) method, an etching method, engraving, and the like. In order to prevent image shrinkage and distortion, it is preferable to hold the film in at least two directions, preferably four directions, during perforation.

As a holding method, both ends of the heat-sensitive perforated film in the flow direction are sandwiched between belts to carry out perforation plate making, or holes for transfer are regularly formed at both ends in the flow direction of the heat-sensitive perforated film. There are a method of carrying out perforation plate making while conveying with a belt or a roll having a projection capable of being inserted into a hole, a method of providing nip rolls before and after a platen roll and carrying out perforation plate making while applying tension to the heat-sensitive perforated film.

[0030]

EXAMPLES The measuring methods used in the present invention are shown below. (1) Heat shrinkage stress (g / mm ² ) A film sample with a width of 10 mm was cut out in the longitudinal and transverse directions, set on a chuck connected to a strain gauge (distance between chucks: 50 mm), and heated to each temperature. The resulting stress was detected by immersing it in the above silicone oil. In this case, the measured value takes the maximum value (maximum value) within 10 seconds after immersion. When the maximum is not shown even after 10 seconds, the value after 10 seconds is taken. Since the maximum peak occurs in a short time when the temperature becomes high, a storage type oscillograph or a storage type recorder (for example, Hioki Denki Memory HiCorder 8815) is used to accurately record the stress value for an extremely short period of time. It shall be.

(2) Heat Shrinkage (%) A film sample was cut into 50 mm × 50 mm, and 1
It is left in a hot air circulating constant temperature bath set at 50 ° C. in a state where it can freely shrink, and after 5 minutes, it is taken out and the dimensional change rate is measured. (3) 2% elongation load (g / cm width) A film sample having a width of 10 mm was cut out in the lengthwise direction and the widthwise direction and set in a tension measuring device (between chucks: 100 mm). It was stretched at a pulling rate of 5 mm / min and the load at 2% elongation was read.

(4) Center Line Average Roughness (Ra) and Maximum Roughness (Rmax) It was measured using Surfcom 550A manufactured by Tokyo Seimitsu Co., Ltd. The measurement condition is CUTOFF = 0.25mm, TRAVERS
ING LENGTH = 2.5 mm, speed = 0.03 m
m / sec, magnification = 50,000 times, stylus tip = 5 μmR (made by Diamond). The measurement was performed 5 times, and the average value of 3 points was taken excluding the maximum value and the minimum value.

(5) Perforation sensitivity (μJ / dot) Amino-modified silicone oil (KF39 manufactured by Shin-Etsu Chemical Co., Ltd.)
3) is applied to a heat-sensitive film coated with 50 mg / m ² of 150
Overlapping mesh gauze, Okura Denki Co., Ltd. printing device T
H-PDM (Thermal head is TPH256R manufactured by Toshiba Corp.)
In (use), while changing the plate making energy (using the thermal head surface temperature as a parameter), a pattern of all dot printing (black solid) and every other dot printing (1/2 pattern) was made. The plate-made heat-sensitive film is independently wound around a printing drum of Risograph RC335 manufactured by Ideal Science Co., Ltd. to perform printing, and the print density (OD) of the printed matter (black solid portion) is determined by a hand-held reflection densitometer D manufactured by Dainippon Screen Mfg. Co., Ltd.
The perforation sensitivity was defined as the plate making energy at which OD = 1.0 as measured by M-800, and the evaluation was that the energy was 80 μJ /
Less than dot is "◎", 80μJ / dot or more, 9
Less than 5 μJ / dot is “○”, 95 μJ / dot or more,
Less than 115 μJ / dot was “Δ”, and 115 μJ / dot or more was “X”.

(6) Transportability The transportability was evaluated by winding the heat-sensitive film coated with 50 mg / m ² of the above silicone oil on a predetermined paper tube and hanging it on a lithograph RC335 for plate making and printing. In particular, by observing whether or not the printing plate can be formed, the occurrence of film breakage, the occurrence of wrinkles during printing, etc., there are no problems at all, ⊚, and those that are slightly wrinkled but do not seem to have problems. “O”, the plate can be printed, but wrinkles are likely to affect the printed matter, and “Δ” indicates that the plate cannot be printed.

(7) Image distortion (%) Fax test chart No. 1 of the Institute of Image Electronics Engineers of Japan. 1 WP
The original was used as the original to perform plate-making printing, and the sizes of the printed matter and the original were measured to determine the shrinkage rate or elongation rate (%) of the image. A value of less than 2% is "◎", 2% or more and less than 5% is "○", 5%
More than 10% less than "△", more than 10% "x"
And

The thermoplastic resin composition used in this example is shown below. Composition 1: Acid component is terephthalic acid, alcohol component is 70 mol% ethylene glycol, 30 mol% 1,4-cyclohexanedimethanol, [η] = 0.80,
A substantially amorphous thermoplastic polyester resin having a Tg of 79 ° C.

Composition 2: Polyethylene terephthalate / isophthalate copolymer ([η] = 0.70, melting point = 215) copolymerized with isophthalate in a proportion of 20 mol%.
C, Tg = 65 ° C.) Composition 3: [η] = 0.8, melting point = 255 ° C., Tg = 7
Polyethylene terephthalate at 5 ° C. Composition 4: Polybutylene terephthalate / isophthalate copolymer ([η] = 1.00, melting point = 180 ° C., Tg = 3) copolymerized with isophthalate in a proportion of 20 mol%.
0 ° C) Composition 5: Ethylene content 2.7% by weight, MI = 5.5
Ethylene-propylene copolymer having a melting point of 139 ° C. Composition 6: Ethylene content 44 mol%, MI = 3, melting point =
165 ° C ethylene-vinyl alcohol copolymer

[0038]

Example 1 and Comparative Examples 1 and 2 Composition 1 had an average diameter of 3.
Resin composition (A) containing 0.2% of 5 μm silica and 70% by weight of ethylene-vinyl acetate copolymer (ethylene content: 14% by weight, MI = 3.5) as a reinforcing layer (B),
15% by weight of ethylene-propylene copolymer, ethylene-
Using a mixed composition of 15% by weight of α / olefin copolymerized elastomer and 2% by weight of a glycerin fatty acid ester-based surfactant, coextrusion from a circular die into a three-layer state of A / B / A, and multi-stage In the hood provided in the shape of a tube, at the stretching start temperature of 105 ° C and the stretching end temperature of 95 ° C, the tube is simultaneously biaxially stretched to 4.5 times the length and 5.5 times the width, and then cooled with 20 ° C cold air. Then, it was folded, heat-treated and collected. The thickness of the film is 2 μm (Comparative Example 1),
Three types of 8 μm (Example 1) and 15 μm (Comparative Example 2) were prepared. The 2 μm film was heat-treated again. The evaluation results of each film are shown in Table 1.

In Comparative Example 1, since the film thickness is as thin as 2 μm, the perforation sensitivity is high even if the maximum value of the heat shrinkage stress (ORS) is small, but there is a problem in transportability. Comparative Example 2
15μm thick, poor perforation sensitivity, 115mJ / dot
Almost no energy was pierced.

[0040]

Example 2 and Comparative Examples 3 and 4 In Example 1, a resin composition obtained by blending 95% by weight of Composition 1 and 5% by weight of Composition 6 was used in place of the resin composition (A) ( Example 2), a composition 1 containing 2% of silica having an average diameter of 8 μm (Comparative Example 3) and a composition 1 using as it is (Comparative Example 4) were formed into films in the same manner as in Example 1 ( Thickness is 8μ
m).

The evaluation of each film is shown in Table 1. Comparative Example 3
In Comparative Example 4, since the Ra was large, the air layer between the TH and the film was thick and the perforation sensitivity was poor, and in Comparative Example 4, Ra was small and slippage in the printing machine was poor, and the plate could not be deposited.

[0042]

[Examples 3 to 5 and Comparative Examples 5 to 7] In Example 1,
When the stretching temperature was 120 ° C. (Comparative Example 5), spherical spherical silica (spherical diameter 1 μm) was added to the composition 2 instead of the resin composition (A).
m, monodisperse) of 0.3% was used (Example 3), 95% by weight of composition 3 and 5% by weight of composition 6 were used.
Composition 1 when blended (Example 4)
50% by weight of the composition 4 and 50% by weight of the composition 4 and 0.3% of a spherical silicone resin (spherical diameter 1 μm, monodisperse).
% Was used (Example 5), and 0.3% of spherical silica (sphere diameter 3 μm, monodisperse) was added to the composition 3 (Comparative Example 6). And evaluated. The evaluation results are shown in Table 1.

All of the examples were excellent in perforation sensitivity and transportability, and among them, the film shown in Example 4 was excellent. In Comparative Example 5, since the heat shrinkage stress is small, the perforation sensitivity is poor. Further, in Comparative Example 6, the heat shrinkage rate is small, and even if the heat shrinkage stress is large, the perforation sensitivity is poor. Next, a resin composition obtained by adding 0.2% of silica having an average diameter of 3.5 μm to the composition 7 was stretched at a stretching temperature of 60 ° C. by tubular stretching 3 times in length and 3 times in width to obtain a film having a thickness of 15 μm. (Comparative example 7). When the film was evaluated, an elongation load of 2% was 70 g /
Although the width was as small as cm, and the thickness was as thick as 15 μm, the transportability was poor.

[0044]

[Embodiment 6] A plate making / printing machine in which the applied voltage and the applied time (pulse width) to TH can be freely changed was manufactured (TH
Is TPH256R manufactured by Toshiba Corp.). As the platen roll, a rubber roll having 150 mesh, a line width of 30 μm and a height of 50 μm formed on the surface of the roll was used.

By mounting the film of Example 1 on this prototype,
Plate making was performed at an applied voltage of 18 V, a pulse time of 0.45 msec, and a heat generation temperature of 380 ° C. Facsimile test chart No. Image processing was performed in the photo mode using 1WP as a document. When it was wound around the printing drum, it had some wrinkles, but the printed matter was clear. here,
Wrinkles tended to be difficult to enter when the tension was increased a little when wound around the printing drum. Moreover, the distortion of the image was “◯”.

Further, when the above test was carried out using a conventional platen roll having no convex portion on the surface, perforation of the film was obstructed and the image was unclear. Further, as a mechanism for suppressing shrinkage due to heat during plate making, when the film carrying means in the plate making machine of the plate making / printing machine is a means for carrying by sandwiching the both ends of the film with belts, there is almost no distortion of the printed image. ◎ ”.

[0047]

Examples 7 to 9 and Comparative Example 8 Platemaking and printing were carried out in the same manner by using platen rolls having mesh surface convex portions shown in Table 2 formed on the surface thereof. In all of the examples, the printed matter was clear, and the image distortion was also “◯”. Comparative Example 8 Due to the small height of the convex portion, only printed matter having an inferior image was obtained by inhibiting perforation.

[0048]

[Embodiment 10] An endless belt was formed in the plate making means.
A device was provided in which a 0-mesh polyester mesh was superposed on the film in the feeding process of the heat-sensitive film, passed between the TH and the conventional platen roll, and then returned to the feeding process of the film again. The running speed of the endless belt was synchronized with the feeding speed of the heat-sensitive film.

When the film of Example 1 was applied to the above apparatus and plate making / printing was carried out, a clear printed portion was obtained and the distortion of the image was also “⊚”.

[0050]

[Examples 11 to 13 and Comparative Example 9] Plate-making / printing was carried out by replacing the polyurethane endless belt having convex portions shown in Table 3 with the endless belt of Example 10. In all of the examples, the printed matter was clear and the image distortion was also "A". Since the height of the convex portion was small in Comparative Example 9, only printed matter having an image inferior was obtained by inhibiting perforation.

[0051]

[Table 1]

[0052]

[Table 2]

[0053]

[Table 3]

[0054]

Since the film of the present invention can be applied to a plate making machine without using a porous support such as Japanese paper, the master cost can be significantly reduced, and white spots due to the fiber grain of Japanese paper do not occur. A printed matter can be obtained. Further, when the film of the present invention and the perforation plate making method of the present invention are combined, the printed image does not shrink even in an image with many perforated portions such as a photographic original, and since the holes are not connected to each other, the resolution is high and the printed matter is not clear. Is obtained.

Claims (2)

[Claims] 1. The thickness of the thermoplastic resin is 4 to 12 μm.
m biaxially stretched film having a maximum value of heat shrinkage stress at 45 to 150 ° C. of 300 to 1500 g / m.
m ² , heat shrinkage at 150 ° C. of at least 30
%, 2% elongation load is at least 100 g / cm width, and center line average roughness (Ra) is 0.02 to 0.40 μm. 2. A heat-sensitive pierceable film having a thickness of 0.01 to 0.5.
A perforation plate making method for forming continuous independent perforations by sandwiching between a line type thermal head and a platen roll which generate heat at 200 to 500 ° C. for msec. The method of perforating a film according to claim 1, wherein the endless belt having regular unevenness is sandwiched between the platen roll side of the heat-sensitive perforating film.