JPH0645268B2 - Method for manufacturing base paper for heat-sensitive stencil printing - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for producing a thermal stencil printing base paper. More specifically, the present invention relates to a method for producing a highly sensitive heat-sensitive stencil printing base paper which is perforated by receiving heat from a xenon flash lamp or a thermal head.

[Prior Art] As a method for producing a heat-sensitive stencil printing base paper, a method in which a heat-sensitive film and a porous support are bonded with an adhesive has been used. Thermoplastic films such as vinylidene chloride copolymer, polypropylene, and polyethylene terephthalate have been used as the heat-sensitive film, and thin paper and Tetoron gauze have been used as the porous support.

Further, as disclosed in JP-A-60-48398, there has been proposed a heat-sensitive stencil printing base paper in which a thin polyester film having a thickness of 4 μm or less is laminated on a porous support in order to increase sensitivity.

[Problems to be Solved by the Invention] However, these have the following drawbacks. When the vinylidene chloride copolymer film is used as a heat sensitive film, the printed characters are not clearly displayed. When a polypropylene or polyethylene terephthalate film is used as a heat sensitive film, clear characters are obtained, but solid printing cannot be obtained.

In the case of a thin polyester film of 4 μm or less,
Frequent tearing during film formation is not stable and yield is poor, and the film becomes thinner and slippery, and handling such as winding is difficult.

Furthermore, wrinkles are generated during the bonding work with the porous support, and stable bonding is difficult, resulting in uneven printing after plate making and printing. On the contrary, when a tension is applied to prevent wrinkles during the laminating work, the elongation of the polyester film is consumed and the base paper for heat-sensitive stencil printing curls or breaks, which makes the laminating difficult. In addition, the stencil sensitivity is poor, and no shade can be expressed.

The present invention solves the above-mentioned drawbacks and provides a method for producing a heat-sensitive stencil printing base paper which is clear in both character printing and solid printing, has no printing unevenness, is excellent in workability, and has excellent stencil sensitivity. It is a thing.

[Means for Solving Problems] In the present invention, a layer (A) mainly composed of polyester and having a melting energy (ΔHu) of 3 to 11 cal / g, and a melt index of 0.5 to 10 g / 10 min. A heat-sensitive stencil printing characterized in that a (B) layer is peeled off after a porous support is attached to the (A) layer surface of a biaxially stretched laminated film composed of a (B) layer made of a certain polyolefin. The present invention relates to a method for manufacturing base paper.

The heat-sensitive stencil printing base paper in the present invention refers to a material which is perforated by receiving heat from a xenon flash lamp, a thermal head or the like as described above.

The (A) layer in the present invention is mainly composed of polyester, and the polyester is a polyester having aromatic dicarboxylic acid as a main acid component and alkylene glycol as a main glycol component.

Specific examples of the aromatic dicarboxylic acid include terephthalic acid,
Isophthalic acid, naphthalene dicarboxylic acid, diphenoxyethane dicarboxylic acid, diphenyl dicarboxylic acid, diphenyl ether dicarboxylic acid, diphenyl sulfone dicarboxylic acid, diphenyl ketone dicarboxylic acid, anthracene dicarboxylic acid, α, β-bis (2- Chlorphenoxy)
Examples include ethane-4,4'-dicarboxylic acid. Of these, terephthalic acid and isophthalic acid are particularly desirable.

Specific examples of the alkylene glycol include ethylene glycol, trimethylene glycol, tetramethylene glycol, pentamethylene glycol, hexamethylene glycol and hexylene glycol. Of these, ethylene glycol is particularly desirable.

Examples of the component to be copolymerized include polyalkylene glycols such as diethylene glycol, propylene glycol, neopentylne glycol, polyethylene glycol, P-oxyrylene glycol, 1,4-dichlorohexanedimethanol, and 5-natritome sulforesorcin. Diol component, adibic acid, sebacic acid,
Dicarboxylic acid components such as phthalic acid, isophthalic acid, 2,6-naphthalene dicarboxylic acid and 5-sodium isophthalic acid, polyfunctional dicarboxylic acid components such as trimellitic acid and pyromellitic acid, oxycarboxylic acids such as P-oxyethoxybenzoic acid Examples include acid components.

The melting energy (ΔHu) (hereinafter simply referred to as ΔHu) of the layer (A) of the present invention is 3 to 11 cal / g, preferably 5
Must be ~ 10 cal / g.

If it is less than 3 cal / g, sticking to the base paper (original) will occur and clear character printing will not be possible. ΔHu is 5 cal /
When it is g or more, clearer character printing is possible.
Further, if ΔHu exceeds 11 cal / g, solid printing, sensitivity, and expression of density (hereinafter referred to as sensitivity) are poor, and the object of the present invention cannot be obtained. Note that Δ
When Hu is 10 cal / g or less, the perforation time can be shortened and the productivity is improved.

It should be noted that it is preferable to add a compound consisting of the following specific monocarboxylic acid or its ester to the layer (A) because the effect of the present invention is significantly improved.

That is, a compound whose main component is a higher aliphatic monocarboxylic acid having 10 to 33 carbon atoms, for example, as specific examples, capric acid, lauric acid, stearic acid, nonadecanoic acid, arachidic acid, pehenic acid, melicinic acid, lignocerine. Typical examples of the compound include acids, cerotic acid, montanic acid, hentriacontanoic acid, petroselinic acid, oleic acid, erucic acid, linoleic acid, and acid mixtures containing these. Of these, preferably, a higher aliphatic monocarboxylic acid compound having 18 to 33 carbon atoms, and more preferably 20 to 32 carbon atoms is added to improve the sensitivity of letters and solid printing and the characteristics of dark and light printing. .

Further, the higher aliphatic monocarboxylic acid ester is obtained by esterifying a part or all of the above higher aliphatic monocarboxylic acid with a monovalent or divalent alcohol having 2 to 33 carbon atoms. Is. Specific examples include montanic acid ethylene glycol ester, montanic acid ethyl ester, montanic acid ceryl, octanosyl lignocerate, melisyl lignocerate, ceryl lignocerate, myricyl serotiate, and ceryl titanate, naturally obtained montan wax. , Carnauba wax, beeswax, candelilla wax,
Nukarou and Ibotaro are also preferably used.

The main component in the present invention means one containing the compound in an amount of 50% by weight or more.

When the number of carbon atoms of the higher aliphatic monocarboxylic acid is less than 10, the bleed-out to the film surface becomes severe, the adhesiveness with the porous support is poor, and the number of carbon atoms is 33.
If it exceeds the range, the sensitivity of solid printing is deteriorated and it is difficult to express light and shade, which is not preferable.

When at least one compound consisting of a higher aliphatic monocarboxylic acid and its ester (hereinafter referred to as a specific wax) is added, the content thereof is 0.005 to 5 parts by weight with respect to 100 parts by weight of polyester. Is preferred, and 0.01 to 3 parts by weight is more preferred. When the content is less than 0.005 parts by weight, not only the content is easily fused with the original, but also the solid printing sensitivity and the gradation expression are often inferior. On the other hand, if it exceeds 5 parts by weight, bleeding out to the surface of the film becomes severe, and there is a problem that the adhesiveness to the porous support is lost.

The polyolefin in the present invention is mainly composed of an ethylene-propylene copolymer, and is one in which ethylene is copolymerized in an amount of 1.0 to 7.0 wt%. A with ethylene content of less than 1.0 wt% and more than 7.0 wt%
Co-drawability with the layer deteriorates and thickness unevenness easily occurs
Printing characteristics may be deteriorated or broken. Furthermore, it is more preferable that the ethylene-propylene copolymer is a random copolymer, from the viewpoint of co-stretchability, and a copolymer having a small thickness unevenness can be obtained.

The ethylene-propylene copolymer of the layer B in the present invention must have a melt index of 0.5 to 10 g / 10 min. If the melt index is less than 0.5 g / 10 min and exceeds 10 g / 10 min, coextrudability, Co-stretchability and uneven thickness cause problems.

The layer (B) has a peeling force of 10 g / when peeled from the layer (A).
The effect of the present invention is remarkable when it is less than or equal to cm, preferably 0.1 to 2 g / cm, and more preferably 0.2 to 0.8 g / cm. If the peeling force is too small, peeling between the film layers occurs during stretching or film transportation, uniform stretching cannot be performed, the film is stuck to a stretching roll, the film peels off during film transportation, such as wrinkles and tears. Trouble may occur. On the contrary, if the peeling force is too large, the film cannot be peeled at a high speed, and the film may be broken or pinholes may be formed. Therefore, in order to keep the peeling force within the above range, 0.001 to 1 wt%, preferably 0.005 to 0.5 wt% in the polymer, especially the (B) layer is used.
% Non-granular lubricants should be included.

The non-particulate lubricant may be a substance having a melting point or a softening temperature of 200 ° C. or lower, which is liquid at room temperature or solid at room temperature, and can impart lubricity to the film. They are the following substances. If two or more of these substances are contained in the film,
It is sufficient that the total amount of them is within the above content range.

Specific examples of non-particulate lubricants include aliphatic hydrocarbons, liquid paraffin, microcrystalline wax, natural paraffin, synthetic paraffin, polyethylene wax,
Polypropylene wax etc.

Higher fatty acid or its metal salt Stearic acid, calcium stearate, hydroxystearic acid, hydrogenated oil, sodium montanate, etc.

Fatty acid amide, stearic acid amide, oleic acid amide, erucic acid amide, ricinoleic acid amide, behenamide, methylenebisstearamide, etc.

Fatty acid ester n-butyl stearate, methyl hydroxy stearate, myricyl serotinate, polyhydric alcohol fatty acid ester, ester wax and the like.

Fatty acid ketone, ketone wax, etc.

Fatty acid alcohol Lauryl alcohol, stearyl alcohol, myristyl alcohol, cetyl alcohol, etc.

Partial ester of fatty acid and polyhydric alcohol Glycerin fatty acid ester, hydroxystearic acid triglyceride, sorbitan fatty acid ester, etc.

Nonionic surfactant Polyoxyethylene alkyl ether, polyoxyethylene phenyl ether, polyoxyethylene alkylamide, polyoxyethylene fatty acid ester, etc.

Silicone oil Linear methyl silicone oil, methylphenyl silicone oil, modified silicone oil, etc.

Fluorine-based surfactants Fluoroalkylcarboxylic acid, perfluoroalkylcarboxylic acid, monoperfluoroalkylethyl phosphate, perfluoroalkyl sulfonate, etc.

In addition, the average particle size of 0.0
Inorganic fine particles of 01 to 1 μm, for example, dry silica, wet silica, zeolite, calcium carbonate, calcium phosphate, kaolin, kaolinite, clay, talc, titanium oxide, alumina, zirconia, aluminum hydroxide, etc. are added to the (A) layer and / or 0.01 to 0.5 in the (B) layer
In many cases, the effect of the non-particulate lubricant can be synergistically enhanced if it is contained by weight%.

The heat-sensitive film of the present invention needs to be a biaxially stretched film, and uniaxial or unstretched film causes unevenness of perforation,
Even after printing, missing parts are likely to occur. The degree of biaxial stretching is not particularly limited, but the plane orientation coefficient is 0.09 to 0.98.
Are preferred for the present invention.

Although the thickness constitution of the laminated film of the present invention may be arbitrary, from the use of the present invention, the thickness of the layer (A) is preferably 0.1 to 5 μm, more preferably 0.2 to 3 μm. It is preferable in view of printing characteristics and ease of peeling the layer (A) from the layer (A) after the porous support is attached to the layer (A).

The film thickness of the layer (B) in the present invention is not particularly limited, but is preferably in the range of 0.5 to 20 μm, more preferably 1.0 to 10 μm at the time of bonding with the porous support. It is preferable from the viewpoints of wrinkles, prevention of elongation, improvement of adhesive strength with the porous support, and easy peeling of the (B) layer from the (A) layer after the porous support is bonded.

The porous support of the present invention is not particularly limited, but examples thereof include tetron gauze, Japanese paper, non-woven fabric and the like. The layer structure which is the essence of the present invention and the method for producing the heat-sensitive stencil printing base paper are such that the specific (A) layer and (B) layer described above have a structure of, for example, A / B or A / B / A, It is necessary to adhere a porous support to this (A) layer, and then peel off the (B) layer to obtain the constitution of the base paper for heat-sensitive stencil printing, that is, the layer constitution to be A / porous support and the manufacturing method. .

Only the specific (A) layer heat-sensitive film causes wrinkles during film winding, making it difficult to wind, and stretching during continuous lamination with a porous support, causing wrinkles and poor adhesion. It is difficult to continuously and stably bond the sheets because of the occurrence of curling and curling after the bonding.

[Characteristic Measuring Method and Effect Evaluation Method] Each characteristic used in the present invention is evaluated by the following methods.

(1) Crystal melting energy [ΔHu (cal / g)] is PER
It was determined from the area of the heat-sensitive film at the time of melting using a DSC-2 type manufactured by KIN ELMER.

This area is the area from the baseline to the endothermic side when the temperature rises, and the area until it returns to the position of the baseline when the temperature is further raised.A straight line connects the melting start temperature position to the end temperature position. The area (a) was calculated. In (indium) was measured under the same measurement conditions of DSC, and the area (b) was set to 6.8 cal / g, and the value was calculated by the following formula.

a / b × 6.8 = ΔHu (cal / g) (2) Heat shrinkage The film was sampled in a width of 1 cm and a length of 30 cm, and a mark was placed at a position 5 cm from one end of the film, and further from there. Mark the position at 20 cm.

A load of 3 g was applied to the tip of this film, and Tabai Co., Ltd.
After processing at 150 ° C. for 15 minutes in “Perfect Open” manufactured by the company, the length of the mark on the film was measured (length Lcm after processing) and calculated from the following formula.

Heat shrinkage rate (%) = {(20-L) / 20} × 100 (3) Plate making: Printing characteristics (A) Evaluation of character printing Character sharpness evaluation JIS 1st level characters with a character size of 20 mm As a base paper (original) of the above, a porous support made of Tetoron gauze and the heat-sensitive film of the present invention (similarly to Examples and Comparative Examples) are attached to each other, and "RISO business card pretend" plate making, printer ( A plate made by using Ideal Science Co., Ltd. and printed was evaluated as follows.

Evaluation was made with the naked eye in three grades of ○, △, and ×, ○ looks like the original paper, and × is different from the original paper and the lines have been partially cut or stuck to make it unreadable. Say In the middle, that is, there is a cut portion, but a legible one is shown by a triangle mark.

Character size 5.0 mm using the same plate making and printing machine as in the evaluation item for character thickness unevenness
The characters on the mouth were printed, and the printed state was visually evaluated.

Compared to the characters on the original paper (original), the characters that are clearly uneven in thickness and cannot be read are shown as ×, and those that have uneven thickness but are readable and usable are marked with Δ. Those having no thickness unevenness are indicated by a circle.

Character print sensitivity evaluation Pencil hardness 7H, 6H, 5H, 4H, 3H, 2H, H 7
A type was prepared, and a manuscript in which characters were written at a basting pressure of 150 g was used as a manuscript, and this manuscript was used to evaluate whether the characters were legible or not. When written in 7H, the color becomes the thinnest and the sensitivity is highest, and as H becomes higher, the black becomes darker and the sensitivity deteriorates.

(B) Evaluation of solid printing Evaluation of sharpness of solid printing ● Using (1 to 5 mmφ base paper (rounded and blackened inside), the same plate-making and printing as above was performed as follows. evaluated.

The size of the base paper was used as a reference, and the judgment was made by the unevenness (partial) of the contour. A product with an unevenness of 200 μm or more compared to the size of the base paper is considered to have poor appearance and is unclear, and is marked with an X mark.
Unevenness of less than μm was made clear and indicated by a circle.
The intermediate one is indicated by a triangle. Depending on how you use it, you can also use the one marked with a triangle.

Correspondence with the base paper size of solid printing Perform printing in the same manner as in the section above, evaluate the size in all directions (at positions of 0 and 180 °, 45 ° and 225 °, 90 ° and 270 °, 135 °) and The correspondence between size and size was evaluated. Those that differ by more than 500 μm from the base paper size (sometimes large and some small) are considered to have poor compatibility, x
It is indicated by a mark. Those having a thickness of 100 μm or less are marked with “◯” as having good compatibility. The one in the middle is indicated by a triangle, but it can be used depending on the application.

Evaluation of sensitivity of solid printing and expression of light and shade The density was measured with a "Macbeth" reflection densitometer, RD-918 (USA, manufactured by kollmorgen), and the solid print density of the original and the density after plate making and printing were compared.

First, with the above-mentioned densitometer, the concentration is 0.90, 0.50, 0.3.
A solid-printed original having a size of 15 mm was prepared so as to be 5, 0.20. Then, using this manuscript, plate making in the same manner as above,
Printed.

The printed matter was measured with the above-mentioned densitometer, and the sensitivity for each density was obtained using the following formula.

Sensitivity for each density = Density after printing for each density / Original density for each density When all the sensitivities for each density are 0.8 or more, it is indicated that the sensitivity and the lightness and shade are expressed well by ◎ marks, and 0.7 or more or more.
Less than 0.8 is marked with ○, 0.6 or more and less than 0.7 is marked with △,
Those having a value less than 0.6 are indicated by x, because the sensitivity and the expression of light and shade are poor. When all the sensitivities for each concentration are satisfied, and if any one is bad, it is ranked below that.

(c) Releasability from the original It means the peelability between the original after plate making and the heat-sensitive stencil printing base paper, and it should be able to be peeled without any resistance.
Marks and originals that are stuck but that can be peeled off without various defects in the plate making part are marked as workable, but can be used, and marked as △, and peeling creates defects in the plate making part. Items that sometimes break were marked as unusable with a cross.

(D) Number of printed sheets In order to check the durability, the number of sheets was measured until the thermosensitive film was slightly torn by a printing machine and the same characters and solid printability as the first sheet were not obtained.

(4) Curling property The heat-sensitive stencil printing base paper was evaluated in the following manner in the state where the plate making was completed by the same plate making machine as described above.

Cut the heat-sensitive stencil printing base paper after plate making into 5 x 8 cm size,
This was placed on a flat table with the surface of the heat-sensitive film facing up, and those that did not curl at all were marked as good, those that floated by 10 mm or more were marked as bad, and the intermediate one was marked with Δ.

(5) Plane Orientation Coefficient The refractive index (N _Z ) in the thickness direction of the film of the present invention and the film of the present invention are kept at a temperature 50 ° C. higher than the melting point for 5 minutes (however, they are sandwiched by a glass plate so that the surface does not become uneven), This sample was taken out, the refractive index (N _ZO ) in the thickness direction was calculated, and was calculated by the following formula.

The surface orientation coefficient = Z _Z / N _ZO refractive index was measured using an Atsube refractometer.

(6) Continuous and stable bonding with porous support Wrinkle prevention The degree of wrinkling that occurs when the porous support (Tetron gauze) and the film of the present invention or a conventional heat-sensitive film are dry laminated It appeared in. Those with no wrinkles were marked as good, and those with wrinkles, which were not wrinkled after lamination, were marked as unusable.

In the middle of this, that is, wrinkles were observed in the laminating process, but no wrinkles were observed in the heat-sensitive stencil printing base paper after lamination is indicated by a triangle mark.

Adhesiveness It means the adhesiveness between the Tetoron gauze used as a porous support and the heat-sensitive film, and a scotch tape was attached to each surface, which was peeled off and evaluated.

If the Tetron gauze is completely peeled off, the adhesive strength is insufficient ×
Marked with a mark, and if it does not peel at all, the adhesive strength is sufficient ○
It is indicated by a mark. The part that peels off partially is indicated by a triangle.

(7) Peelability from layer (A) to layer (B) Separated between sampling layers A and B with a width of 2 cm and a length of 5 cm, and attaching the films of layers A and B to the Tensilon clips respectively 200 mm Pulling at a speed of
The strength at this time showed peelability. (Peeling at 180 °) When the strength was 1.0 g / cm or less, good peelability was indicated by the mark ◯, and when 2.0 g / cm or more, the peelability was bad, and the mark was indicated by the mark X. The middle of this is indicated by a triangle.

(8) Coextrusion property The polymers of the A and B layers were coextruded, and the thickness unevenness of the A layer of the cast film was evaluated.

The width of the evaluated film was within the range of the central portion of the entire width of 50%.

If the thickness unevenness is 10% or less, it is marked as good, and
Those having a content of 15% or more were indicated by x as poor coextrudability.
The middle of this is indicated by a triangle.

(9) Co-stretchability The film thickness of the layer A after biaxial stretching was evaluated as unevenness. The evaluated film width was within the range of the central portion of the entire width of 50%.

Those having a thickness unevenness of 20% or less are indicated as ◯, and those having a thickness unevenness of 30% or more are indicated as x, indicating that they cannot be used.
The intermediate one is indicated by a triangle.

(10) Melt. Index (MI) It was carried out at 230 ° C. according to ASTM-1238, method B.

(11) The ethylene content (polymer property of layer B) can be measured by using the absorption at 731 cm ^{-1 in} the infrared absorption spectrum and the absorption at 973 cm ^-1 as a reference band.

The degree of randomness is 7 in the infrared absorption spectrum.
Represented by the ratio of the absorbance of 20 cm ^-1 and 731cm ^-1. This ratio (A720 / A731) is named a randomness index. [Example] Example 1, Comparative Examples 1 to 3 The present invention will be described based on Examples.

Comparative Example 1 is polyethylene terephthalate (hereinafter PET).
In Comparative Example 3, 0.51 part by weight of carnauba wax was added to 100 parts by weight of ethylene terephthalate isophthalate copolymer (hereinafter referred to as PET / I) copolymerized with 20 mol% of isophthalate. (Both IV = 0.6) as a feed to the extruder,
It is melt extruded from a single-layer T-die at 80 ° C, wound around a rotating cooling roll (temperature 50 ° C) and cast, and this film is heated to 80 ° C and stretched 3.0 times in the longitudinal direction, followed by hot air at 80 ° C. It is sent to the stenter heated by and is stretched 3.0 times in the width direction.
Heat treatment was performed at 50 ° C. for 5 seconds to obtain a 2.0 μm biaxially stretched film.

In Comparative Example 2 and Example 1, the B layer has an ethylene content of 5 wt.
%, M16 g / 10 min of ethylene / propylene copolymer (hereinafter sometimes referred to as EPC), and the same polymer as Comparative Examples 1 and 3 was used as the A layer in the order of two-layer T.
The film was coextruded from a die to obtain an A / B two-layer film, and the films shown in Table 1 were obtained under the same stretching and heat treatment conditions as in the above-mentioned single layer.

Each of these films (on the layer A side in the case of a two-layer film)
Was adhered with a dry laminator using a tetron gauze using an adhesive "Byron 300" for dry lamination (manufactured by Toyobo Co., Ltd.), and then the layers A and B were peeled off to obtain a heat-sensitive stencil printing base paper.

In Comparative Examples 1 and 2 and Example 1, even if the film tension is freely changed over a wide range, wrinkles do not occur and sufficient adhesive force is obtained, but in Comparative Example 3, it is continuously stable and wrinkles do not occur. Moreover, sufficient adhesive strength cannot be obtained. That is, from this result, the heat-sensitive film having excellent plate making and printing characteristics is a composite film, and after bonding and peeling, there is no wrinkle and sufficient adhesive force cannot be obtained.

Further, in the monolayer film of Comparative Example 3, film breakage occurs frequently (10 to 20 times / 8 hr) in the process of biaxial stretching, but the breakage does not occur at all by compounding.

Further, in the single-layer film, there was generated a wrinkle during winding, but by combining the films, a wrinkle was not generated at all.

Examples 2 to 4 and Comparative Examples 4 to 6 Comparative Examples 4 and 5, Examples 2, 3, 4 and Comparative Example 6 in this order, the MI of the ethylene-propylene copolymer of the B layer was 20, 1
Raw materials which were changed in order of 3, 10, 5, 0.5 and 0.1 g / 10 min were used.

The film was coextruded using a three-layer T die so that the film had a three-layer structure of A / B / A, and the same production conditions as in Example 1 were used to obtain a biaxially stretched film.

This film was laminated with Tetoron gauze in the same manner as in Example 1. The bonding at this time was performed twice because there were two layers of layer A. The evaluation results of each characteristic are shown in Table 1.

From this result, even if a layer A is used as a composite film having excellent plate-making and printing characteristics, if a layer B is used within a specific range, coextrusion property, costretchability, and porous support are obtained. It can be seen that it is not possible to obtain a product having excellent stickability to the body and plate making / printing characteristics.

Examples 5 to 9 and Comparative Examples 7 to 8 As raw materials for the A layer, ethylene terephthalate, isophthalate, and copolymer were used. Comparative Example 7, Examples 5-9
The order of isophthalate is 30mol%, 22.5mol
%, 20mol%, 17.5mol%, 15mol%, 12.5m
The copolymer was used so that the ol% would be 100% by weight, and 0.51 part by weight of carnauba wax was added (IV = 0.6). An ethylene propylene copolymer having an ethylene content of 5 wt% and an MI of 6 g / 10 min was used as a raw material for the B layer, which was supplied to an extruder, melt-extruded from a two-layer T die at 280 ° C., and wrapped around a rotating cooling roll (temperature 50 ° C.). And cast into an A / B two-layer film. This film is heated to 80 ° C. and stretched 3.0 times in the longitudinal direction,
Subsequently, it was fed into a stenter heated with hot air of 80 ° C., stretched 3.0 times in the width direction, and subsequently heat-treated in the stenter at 150 ° C. for 5 seconds to obtain a 2.0 μm biaxially stretched film.

In Comparative Example 8, polyethylene terephthalate homopolymer was used as the raw material for the layer A, and the same conditions were used except that each temperature condition was increased by 10 ° C.

The content of carnauba wax in the obtained heat-sensitive film was 0.5 part by weight based on 100 parts by weight of the copolymer.

This two-layer film was attached and peeled off in the same manner as in Example 1.
Plate making and printing tests were conducted.

Examples 10 to 15 As a raw material for the A layer, the proportion of isophthalate is 20 mol%
90% by weight of ethylene terephthalate, isophthalate, and a copolymer were blended with 10% by weight of polyethylene terephthalate homopolymer, and 100 parts by weight of this was added so that the content of carnauba wax was as shown in Table 2. Other conditions were the same as in Example 1.

Example 16 As shown in Table 2, a specific wax having a different number of carbon atoms as a main component was used, and the addition amount was 0.2.
1 part by weight was added. Other conditions were the same as in Example 1, and the film thickness was adjusted to 0.5 μm.

As described above, the two-layer film made of A / B of Examples 5 to 16 and Comparative Examples 7 and 8 was attached to Tetoron gauze in the same manner as in Example 1, the B layer was peeled off, and then the plate making and the printing test were performed. The results shown in Table 2 were obtained.

From this result, by using a biaxially stretched film made of polyester having a specific melting energy as the A layer, a clear and sensitive film having no thickness unevenness in character printing can be obtained. Clear even in solid printing,
A heat-sensitive film having good size compatibility and high sensitivity was obtained.

EFFECTS OF THE INVENTION The present invention provides an A / B or B / A / B biaxially stretched laminated film in which the A layer made of a specific polyester and the B layer made of a specific ethylene / propylene copolymer are formed on the A layer surface. The following excellent effects could be obtained by using the manufacturing method in which the B layer is peeled after the porous support is bonded. That is, (1) characters after printing and solid printing can be obtained clearly.

(2) The film formation is stable, there is no breakage, and the yield is greatly improved.

(3) The winding property is improved.

(4) Elongation, wrinkles, tears, etc. do not occur at the time of laminating with the porous support, continuous and stable laminating is possible, curling of the base paper for heat sensitive stencil printing is prevented, and plate making and printing due to wrinkles The print unevenness afterwards disappears.

(5) The stencil sensitivity is improved, and it is possible to express shades.

(6) Co-stretchability is excellent, thickness unevenness is good, and printing unevenness is eliminated.

(7) The peelability of the layers (A) and (B) is improved after bonding with the porous support, and wrinkles and the like are eliminated.

Continuation of the front page (56) Reference JP-A-61-69461 (JP, A) JP-A-53-69709 (JP, A) JP-A-51-2513 (JP, A) JP-B-48-1009 (JP , B1) Japanese Patent Publication Sho 48-1532 (JP, B1)

Claims (1)

[Claims] 1. Melting energy (ΔHu) is 3 to 11 cal / g mainly composed of polyester. After bonding the porous support to the (A) layer surface of the biaxially stretched laminated film composed of the (A) layer and the (B) layer made of a polyolefin having a melt index of 0.5 to 10 g / 10 min. And (B) layer is peeled off and removed, and a method for producing a heat-sensitive stencil sheet.