JPH058568A - Film for thermal stencil paper - Google Patents

Abstract

PURPOSE:To provide a film for thermal stencil paper imparting sharpness and high gradation properties in both of character printing and solid printing, generating no printing irregularity and excellent in sticking preventing properties, easy adhesiveness and antistatic properties. CONSTITUTION:As a base film for thermal stencil paper, a biaxially stretched film wherein a crystal m.p. Tm is 220 deg.C or lower, glass transition temp. Tg is 0 deg.C or higher and crystal melting half breadth W1/2 is 14 deg.C or less is used.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat-sensitive stencil printing base paper film which is perforated by receiving heat from a xenon flash lamp or a thermal head.

[0002]

2. Description of the Related Art As a heat-sensitive stencil printing base paper, a film in which a heat-sensitive stencil printing base paper film and a porous support are bonded together with an adhesive is usually used. Vinylidene copolymer films, polypropylene films and polyethylene terephthalate copolymer films have been used, and thin paper, Tetoron gauze, etc. have been used as the porous support (for example, JP-A-53-49519).

However, these have the following drawbacks. 1) When solid printing is performed, uneven printing is likely to occur. 2) Since the thickness unevenness is large and the flatness is poor, the suitability for lamination with the porous support is poor, and uneven printing is likely to occur. 3) Light and shade appear on the printed part, and a clear image cannot be obtained. 4) In addition, unevenness in the thickness of characters partially occurs. 5) No thin black characters appear, resulting in poor gradation. 6) The adhesive used for adhesion to the porous support causes a difference in sensitivity and resolution.

In general, when a plastic film is used as a film for heat-sensitive stencil printing paper, a stick phenomenon appears in which the film partially adheres to the thermal head due to the heat applied from the thermal head. If this phenomenon occurs, not only the film will not run smoothly, but also the thermal head will be significantly contaminated and the sharpness at the time of punching will be impaired. In addition, there is a problem that adhesion with a document occurs when punching with a flash lamp.

Further, since the biaxially stretched polyester film is an insulator, it is significantly charged by static electricity, which may cause wrinkles or the like in post-processing or dust or the like to cause perforation failure. Since the surface of the axially stretched polyester film is highly oriented, it has a defect that the adhesiveness of the adhesive is poor. Further, since the film is thin, it has a drawback that the stretching stability is poor.

[0006]

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to solve the above-mentioned drawbacks, and clear both character printing and solid printing with high gradation and no printing unevenness, and stickiness prevention, easy adhesion and A stable film for heat-sensitive stencil printing base paper having excellent antistatic properties is provided.

[0007]

In order to solve the above-mentioned drawbacks, the present inventors have the following constitution, that is, the crystal melting point Tm is 20.
A film for heat-sensitive stencil printing paper, characterized by using a biaxially stretched film having a glass transition temperature Tg of 0 ° C or lower, a crystal melting half-value width W _1/2 thereof of 14 ° C or lower. Is.

The film for heat-sensitive stencil printing base paper of the present invention comprises
Biaxially stretched film made of a specific thermoplastic resin (hereinafter,
It is referred to as a heat-sensitive film) and a release layer or an antistatic layer laminated on it.

In the present invention, the heat-sensitive film is to form a portion in which characters and other parts of the base paper to be printed are perforated when exposed to flash light or contacted with a thermal head (that is, due to heat).

In the present invention, the heat-sensitive film is required to be biaxially stretched, and uniaxially stretched or unstretched film causes unevenness of perforations, and a missing portion occurs even after printing. In addition,
The degree of biaxial stretching is not particularly limited, but the plane orientation coefficient is 0.
Those of 90 to 0.98 are preferred for the present invention.

The crystalline melting point Tm of the heat-sensitive film of the present invention is 2
20 ° C or lower, preferably 190 ° C, more preferably 1
Must be below 70 ° C. This is because when Tm exceeds 220 ° C., the printing sensitivity decreases. Further, the half width W _1/2 of the crystal melting peak is 14 ° C. or less, preferably 1
It should be below 0 ° C, more preferably below 8 ° C. The half-value width W _1/2 represents the sharpness of the crystal melting peak, and is represented by the temperature range in which the crystal is melting, which corresponds to 1/2 of the peak height, and the W _1/2 is large. It means that there is a wide temperature range from the start to the end of melting, but this is not synonymous with the temperature deviated from the baseline of the thermograph obtained by scanning calorimeter (DSC), but it is the same. I often do it. When this W _1/2 becomes smaller than 14 ° C., the difference between the melted portion and the non-melted portion becomes clear, and the so-called resolution is improved. Further, the crystal size becomes uniform, the thermal conductivity of the film also increases, the sensitivity to heat is improved, and the resolution is improved. If W _1/2 exceeds 14 ° C., the resolution, especially in color printing, becomes low, making clear and accurate printing impossible. Here, typical polymers Tm, Tg, W
_{Although 1/2} is shown as a guide, it is clear that this value changes by operations such as stretching and heat treatment.

[0012]

[Table 1]

The glass transition temperature Tg of the heat sensitive film is 0 ° C.
Or more, preferably 20 ° C or more, more preferably 30 ° C
That is all. This is because if the Tg is less than 0 ° C., the handleability of the film deteriorates, and the film quality changes over time.

In the present invention, the heat sensitive film preferably has a melting energy ΔHu of 3 to 12 cal / g, more preferably 5 to 10 cal / g. If the melting energy is less than 3 cal / g, it causes sticking with the base paper (original) and clear character printing is not possible. In addition, ΔH
By setting u to 5 cal / g or more, clear character printing becomes possible. On the other hand, when ΔHu exceeds 12 cal / g,
It becomes a character in which a missing portion is generated, resulting in poor expression of solid printing, sensitivity, and shading. In addition, ΔHu is 10 cal /
When it is less than or equal to g, the perforation time can be shortened and the productivity and quality are improved.

From the above, polyhexamethylene terephthalate is a particularly preferable resin for the film of the present invention. Further, in the present invention, when the characteristics of the heat-sensitive film, that is, the center line average roughness, the maximum roughness and the number of protrusions are within the ranges described below, the effects of the present invention are more remarkably exhibited, which is preferable.

In the present invention, the center line average roughness (Ra) of the heat-sensitive film is preferably 0.05 to 0.3 μm, more preferably 0.09 to 0.25 μm. Center line average roughness is 0.05μ
If it is less than m, winding and handling will be quite difficult and creases will be formed, resulting in a decrease in productivity. On the other hand, when Ra exceeds 0.3 μm, the surface becomes rough and opaque, resulting in a significant decrease in sensitivity.

In the present invention, the heat-sensitive film has a maximum roughness (Rt) of preferably 0.5 to 4.0 μm, more preferably
0.8 to 3.5 μm. If the maximum roughness is less than 0.5 μm,
Slippery property deteriorates, air bleeding is poor, vertical wrinkles are included, and winding property is poor. On the other hand, when it exceeds 4.0 μm, not only the sensitivity is lowered but also the film is broken and the productivity is lowered.

In the present invention, the heat-sensitive film is 1 μmφ
The number of protrusions above is preferably 2,000 to 10,000 / mm ² .
More preferably, it is 2,500 to 8,000 pieces / mm ² . 2,000
If the number is less than 1 / mm ² , slipperiness and windability will deteriorate, and 10,000
When the number of particles / mm ² is exceeded, the transparency is lowered and the sensitivity and the resolution are lowered.

The number of protrusions of 8 μmφ to 20 μmφ is preferably 20 to 1,000 / mm ² , and more preferably 50.
~ 800 pieces / mm ² is good. If it is less than 20 pieces / mm ² , the slipperiness will be poor, and the film will meander during winding and the windability will be poor. On the other hand, if it exceeds 1,000 pieces / mm ² , not only the quality is deteriorated, but also the film is broken and the productivity is lowered.

Further, in the present invention, the heat-sensitive film has a heat shrinkage ratio of preferably 10% or more, more preferably 20% or more, and preferably less than 10% within the range from the melting point of the film to (melting point-50 ° C). In that case, the plate-making sensitivity becomes poor, which may cause a problem in practical use. Further, the heat shrinkage rate at 70 ° C. is more preferably less than 10%.

In the present invention, the thickness of the heat sensitive film is not particularly limited, but is preferably 0.1 to 10 μm, and 0.5.
˜5.0 μm, more preferably 0.9 to 1.8 μm. If the thickness is too thin, unclearness and unevenness in light and shade are likely to occur, and if it is too thick, a missing portion or uneven thickness tends to occur.

In the present invention, in order to control the surface morphology of the heat-sensitive film, that is, the surface roughness, the number of protrusions, and the diameter of the protrusions in the above-mentioned preferred ranges, the inert particles as the thermoplastic resin to be extruded in the production method described later. It is desirable to prepare a master polymer containing the above and blend it with the main polymer. In this case, the master polymer has a melting point of 0 to 100 ° C., preferably 20 to 80 ° C., as compared with the main component polymer.
Higher and / or higher intrinsic viscosity of 0.2 to 1.0 is preferable. Further, the main component polymer and the master polymer are preferably compatible with each other to some extent or more.

Further, it is needless to say that the specific surface morphology can be controlled to some extent by the shear stress at the time of extrusion, the basis weight of the filter, the extrusion conditions and the like.

The inert particles used in the present invention include:
Particles selected from oxides or inorganic salts of elements of Group IIA, IIIB, IVA, IVB of the element period, for example, calcium carbonate obtained as a synthetic or natural product, wet silica (silicon dioxide), dry silica (silicon dioxide) , Aluminum silicate (kaolinite), barium sulfate, calcium phosphate, talc, titanium dioxide, aluminum oxide, aluminum hydroxide, calcium silicate and the like.

The average particle diameter of the above inert particles is 0.1 to 3 μm.
It is preferably m.

Further, the master chip concentration of the inert particles is preferably 0.5 to 10% by weight, more preferably
From 1.0 to 7.0% by weight is preferable for producing a specific surface morphology.

The concentration of the inert particles in the heat-sensitive film also varies depending on the type of particles, the particle size, etc., but is preferably 0.05 to 2.0% by weight, preferably 0.1 to 1.0% by weight in order to obtain a specific surface morphology.

In the present invention, the heat-sensitive film may be added with an additive having an absorption peak in the wavelength range of flash light irradiation.

In the present invention, by providing a release layer on the heat-sensitive film, sticking-preventing property and adhesion-preventing property with the original can be imparted.

In the present invention, the release layer is mainly composed of a mixture of petroleum wax (A), vegetable wax (B) and oily substance (C) which is dissolved, emulsified or suspended in water. is there. Here, the main component means that the weight ratio of the mixture of (A), (B) and (C) is 50% or more, preferably 60% or more.

Examples of petroleum waxes include paraffin wax, microcrystalline wax, and oxidized wax. Among them, oxidized wax is particularly preferable.

Examples of vegetable waxes include candela wax, carnaupa wax, wood wax, oliqury wax, sugar cane wax and the like. In the present invention, a composition comprising the following compounds is particularly preferable.

That is, {rosin or disproportionated rosin, or hydrogenated rosin / α / β-substituted ethylene (α-substituent: carboxyl, β-substituent: hydrogen, methyl or carboxyl) additive} ・ alkyl or alkenyl (each carbon It is particularly preferable to use an ester addition product of a poly (repeating unit: 1 to 6) alcohol of the formulas 1 to 8).

The mixing ratio of petroleum wax and vegetable wax is 10/90 to 90/10% by weight, preferably 20.
/ 80 to 80/20% by weight, more preferably 30/70
It is preferably set to 70/30. 1 vegetable wax
The amount of 0% by weight or more is suitable for obtaining a uniform coating film with good uniform dispersibility when emulsified or suspended in water. Further, when the amount of the petroleum wax is 10 parts by weight or more, the coating film has good slipperiness and good running property at high speed perforation.

In the present invention, a mixture of the petroleum wax (A) and the vegetable wax (B) to which an oily substance (C) is further added is used. Here, the oily substance is a liquid at room temperature or It is a paste-like oil, and examples thereof include vegetable oils, fats and oils, mineral oils, synthetic lubricating oils, and the like. Vegetable oils include linseed oil, kaya oil, saffron oil, soybean oil, cinnamon oil, sesame oil, corn oil, rapeseed oil, tuna oil, cottonseed oil, olive oil, southern oil, camellia oil, castor oil, peanut oil, balm oil, coconut oil. Etc. Fats and oils include beef tallow, pork oil, sheep oil, cacao oil and the like, and mineral oils include machine oil, insulating oil, turbine oil, motor oil, gear oil, cutting oil, liquid paraffin and the like. As the synthetic lubricating oil, those satisfying the requirements described in the Chemical Dictionary (Kyoritsu Publishing Co., Ltd.) can be arbitrarily used. For example, olefin polymerized oil, diester oil, polyalkylene glycol oil, diester oil, polyalkylene glycol oil. , Silicone oil and the like.
Among these, mineral oil and synthetic lubricating oil are preferable. Also, a mixed system of these may be used.

The oily substance (C) should be added in an amount of 1 to 100 parts by weight, preferably 3 to 50 parts by weight, based on 100 parts by weight of the mixture of the petroleum wax (A) and the vegetable wax (B). . If the amount of the oily substance is less than 1 part by weight, the runnability in the high applied energy region is deteriorated. On the other hand, when the amount exceeds 100 parts by weight, the running property in the low applied energy region is deteriorated.

When any one of the vegetable wax, the petroleum wax and the oily substance is used alone, there arises a problem that a uniform coating film cannot be obtained, running property is deteriorated and sticking occurs.

Various additives may be used in combination in the above composition within a range that does not impair the effects of the present invention. Examples thereof include antistatic agents, heat-resistant agents, antioxidants, organic particles, inorganic particles and pigments.

Further, various additives such as dispersion aids, surfactants, preservatives and antifoaming agents may be added to the coating composition for the purpose of improving dispersibility in water.

The center line average roughness (R
a) is 0.03 to 0.4 μm, preferably 0.05 to 0.2 μm, and the release layer has a thickness of 0.005 μm or more Ra.
Hereafter, it is preferably 0.01 μm or more and Ra or less. If the center line average roughness of the release layer is less than 0.03 μm or if the thickness is less than 0.005 μm, sticking tends to occur. Further, when the thickness of the release layer exceeds Ra, the runnability at the time of punching and head contamination are remarkable. Ra is
When it exceeds 0.4 μm, clear perforation and printability cannot be obtained although the stick property is good.

Furthermore, the coefficient of static friction between the surface coated with the release layer and the soda glass at 25 ° C. and 65 Rh (μs
₁ ) is 0.3 or less and the value at 100 ° C (μs
₂ ) and (μs ₁ ) ratio (μs ₂ ) / (μs ₁ ) is 1.0
The following cases are preferable because the sticking prevention property and the head contamination prevention property are particularly excellent.

In the present invention, when the release layer is applied, the coating liquid is preferably a coating liquid dissolved, emulsified or suspended in water from the viewpoint of explosion proof and environmental pollution.

The release layer may be applied to a biaxially stretched film after completion of crystal orientation or may be applied to a film before completion of crystal orientation and then stretched. In order to bring out the effect of the present invention more remarkably. Is particularly preferably the latter method.
The method of applying is not particularly limited, roll coater,
Gravure coater, reverse coater, kiss coater,
It is preferable to apply using a bar coater or the like.

Before coating, the coating surface may be subjected to corona discharge treatment in air or other various atmospheres, if necessary.

In the present invention, the heat-sensitive film is provided with a polymer layer having a sulfonic acid group, whereby the adhesiveness to the porous support can be enhanced and the sensitivity and resolution deterioration due to the adhesive at the time of adhesion can be improved. In addition, antistatic properties can also be imparted. Coating thickness is 0.001-5
μm, preferably 0.01 to 0.4 μm.

In the present invention, in order to impart an oriented sulfonic acid group to the surface layer of a biaxially stretched film made of a thermoplastic resin which is a heat-sensitive film, a composition in which a polymer having a sulfonic acid group is used alone or mixed with another compound Can be achieved by coating a film made of a thermoplastic resin (hereinafter referred to as a thermoplastic resin film) with and stretching the film under specific conditions.

The polymer having a sulfonic acid group means --S
A typical polymer having a sulfonic acid having an O ₃ X group or a salt thereof,

[0048]

[Chemical 1]

In the form of acrylic acid, acrylic ester,
Copolymerized with methacrylic acid, methacrylic acid ester or styrene,

[0050]

[Chemical 2]

A polymer consisting solely of

[0052]

[Chemical 3]

Examples thereof include polymers obtained by using as a part or all of the dicarboxylic acid of various polyesters.

However, among them, the vinyl polymer form is preferable from the viewpoint of water resistance and alkali resistance, and further, sulfonated polystyrene and / or its salt is preferable.

However, X here is H ⁺ , Na ⁺ , L
selected from cationic ions such as i ⁺ , NH ₄ ⁺ , and K ⁺ , and in the case of the present invention, particularly NH ₄ ⁺ , H ⁺ ,
Li ⁺ is particularly preferred.

Further, the introduction rate of the sulfonic acid group monomer in the polymer is preferably 40 to 100 mol% in order to orient and obtain easy adhesion having water resistance and alkali resistance. The weight average molecular weight of the polymer having a sulfonic acid group monomer is 10 to 5,000,000, preferably 2000 to 100.
It is about 10,000.

The resin containing a sulfonic acid group as a monomer can be coated alone on the surface layer of a thermoplastic resin film, but in the case of the present invention, it is particularly used by mixing with another resin. Is preferred. When coated on a thermoplastic resin film, a water-soluble or water-dispersible polymer such as polyester resin, acrylic resin, polyamide resin, urethane resin, vinyl resin, butadiene resin, epoxy resin, silicone resin A resin or a mixture thereof can be used regardless of whether it is thermoplastic or thermosetting.

It is preferable to use polyurethane, polyester, or acrylic resin as the water-soluble or water-dispersible resin from the viewpoint of adhesiveness and transparency. In particular, the use of the above-mentioned sulfonated polystyrene as a sulfonic acid group and a salt thereof mixed with a polyester-based polymer has excellent antistatic properties, transparency, easy adhesion, piercing properties, and cracks in the coating film. It is preferable because a heat-sensitive stencil printing base paper that does not occur can be obtained.

Specific examples of suitable polyurethanes include polyurethanes having carboxylate groups, sulfonate groups,
Having at least one type of sulfuric acid half-ester base,
Among them, ammonium salts can be mentioned.

Specific examples of suitable polyesters include 5-sulfosodium isophthalic acid in an amount of 0.5 to 20.
Mol% copolymerized polyester, polyethylene glycol or ethylene oxide propylene oxide 1 to 30
The thing copolymerized by mol% can be mentioned. Above all,
At least one of terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid, diphenyldicarboxylic acid and adipic acid is used as the acid component, and ethylene glycol or hexane glycol, 1-4-butanediol, diethylene glycol, neopentyl glycol, tetramethylene is used as the alcohol component. It is particularly preferable to use a polyester having at least one of glycol and polyethylene glycol and having an aqueous solution or aqueous dispersion having a viscosity of 1 to 6 cps when diluted by 5% by weight, since the adhesiveness and antistatic property are excellent.

The next suitable acrylic resin is
Examples of the main component include alkyl acrylate or alkyl methacrylate.
It is a water-soluble or water-dispersible resin containing 70 to 0.1 mol% of a vinyl monomer component capable of being copolymerized with 99.9 mol% and having a functional group and having a functional group of 70 to 0.1 mol% and having a number average molecular weight of 200,000. ˜1 million, preferably 300 to 800,000 resins are preferred.

Among them, a copolymer of methyl methacrylate and ethyl acrylate in a ratio of 35/65 to 65/35 (molar ratio) is used as a trunk polymer, and --COOH and --CH ₂ OH are used.
Water-dispersible acrylics in which 1 to 5% by weight of each of the vinyl monomers having the above are introduced are particularly preferable.

The standard of the weight mixing ratio of the polymer (B) having a sulfonic acid or its salt to all other polymers (A) is often in the range of 5 to 95% in the present invention. If it is less than 5% by weight, the effect of improving the adhesiveness and the antistatic property are insufficient, which is not preferable.
On the other hand, if it is more than 95% by weight, the toughness of the coating film becomes poor, which is not preferable. Particularly, when it is 10% by weight to 30% by weight, the balance between alkali resistance, adhesiveness, coating film toughness and antistatic property is good, which is preferable.

To improve the adhesiveness (blocking property), heat resistance, solvent resistance, and mechanical strength of the coating film, a methylol- or alkylol-based urea-based, melamine-based, acrylamide-based, or polyamide-based crosslinking agent is used. A reactive compound such as a resin, an epoxy compound, an aziridine compound, a blocked polyisocyanate, or a vinyl compound may be contained in the coating layer.

In the coating layer in the present invention, if necessary, a defoaming agent, a coating crosslinker, a thickener, an organic lubricant,
Inorganic particles, antioxidants, ultraviolet absorbers, foaming agents, dyes, pigments and the like may be contained.

If necessary, inorganic particles may be added to the coating layer. Typical examples of the inorganic particles are preferably 1 μm or less in average particle size, more preferably 0.5 μm or less in average, and particularly preferably 0.2 μm or less. Specific examples include those having a particle size of not more than μm, such as kaolin, silica, silica sol, calcium carbonate, titanium oxide, barium salt, alumina, molybdenum sulfide, carbon black, and zirconium, but are not limited thereto.

Next, the method for producing the film for heat-sensitive stencil printing base paper of the present invention will be explained, but the invention is not limited to such an example.

First, a heat sensitive film is formed. As a thermoplastic resin, polyhexamethylene terephthalate (P
HT) and inert particles are fed to the extruder to obtain 180-2
It is melted at 20 ° C., extruded from a T-die, adhered to a cooling roll and solidified to obtain a cast film. 50 to 50
Stretching is carried out in the longitudinal direction with a group of rolls heated to 100 ° C. One side of the uniaxially stretched film obtained as described above is subjected to corona discharge treatment, and a petroleum wax diluted to a predetermined concentration on this treated surface, a water-dispersed coating liquid containing a vegetable wax and an oily substance as a main component. Apply. Further, after a coating layer containing a predetermined sulfonic acid group is provided on the surface opposite to the release layer, it is dehydrated in a sufficient preheating step and stretched in the lateral direction while being humidified by pressure steam of 80 to 140 ° C.

The stretching conditions at this time vary depending on the type of raw material used and the amount of copolymerization, but since sticking with the device may occur and the transparency of the film may deteriorate, a method such as making the device non-adhesive may work. Preferably.

The biaxially stretched film thus obtained was heat-set at 100 to 200 ° C. in a tenter in order to impart flatness and dimensional stability to the film, then uniformly cooled and cooled to room temperature. A film for heat-sensitive stencil printing base paper can be obtained by winding.

Further, the film of the present invention may be peeled and separated from a laminated film with another thermoplastic polymer (B) having excellent peelability to obtain a biaxially stretched thermoplastic film. By doing so, a thin film can be stably formed. The polymer (B) is any polymer selected from polyolefin, polyphenylene sulfide, fluorine-based polymer and the like.

The layer (B) has a peel force of 10 g / cm or less, preferably 0.1 to 2 when peeled from the film (A) layer of the present invention.
The effect of the present invention is remarkable when it is in the range of g / cm, 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 maintain the peeling force within the above range, 0.001 to 1% by weight, preferably 0.0
It is recommended to contain 05 to 0.5 wt% of non-particulate lubricant.

A non-particulate lubricant is a liquid having a melting point or a softening temperature of 200 ° C. even if it is liquid at room temperature or solid at room temperature.
Any of the following substances may be used as long as it imparts film lubricity, and the specific substances are as follows.

When two or more kinds of these substances are contained in the film, the total amount thereof should be within the above content range.

Specific examples of non-particulate lubricants include (1) aliphatic hydrocarbon liquid paraffin, microcrystalline wax, natural paraffin, synthetic paraffin, polyethylene wax,
Polypropylene wax etc.

(2) Higher fatty acid or metal salt thereof Stearic acid, calcium stearate, hydroxystearic acid, hydrogenated oil, sodium montanate, etc.

(3) Aliphatic amide stearic acid amide, oleic acid amide, erucic acid amide, ricinoleic acid amide, behenamide, methylenebisstearamide and the like.

(4) Fatty acid ester n-butyl stearate, methyl hydroxystearate, myricyl serotinate, polyhydric alcohol fatty acid ester, ester wax and the like.

(5) Fatty acid ketone Ketone wax etc.

(6) Fatty acid alcohol Lauryl alcohol, stearyl alcohol, myristyl alcohol, cetyl alcohol, etc.

(7) Partial ester of fatty acid and polyhydric alcohol Glycerin fatty acid ester, hydroxystearic acid triglyceride, sorbitan fatty acid ester and the like.

(8) Nonionic surfactant Polyoxyethylene alkyl ether, polyoxyethylene phenyl ether, polyoxyethylene alkylamide, polyoxyethylene fatty acid ester and the like.

(9) Silicone oil Linear methyl silicone oil, methylphenyl silicone oil, modified silicone oil and the like.

(10) Fluorine-based surfactant Fluoroalkylcarboxylic acid, perfluoroalkylcarboxylic acid, monoperfluoroalkylethyl phosphate, perfluoroalkyl sulfonate, etc.

Inorganic fine particles having an average particle size of 0.001 to 1 μm, for example, dry silica, wet silica, zeolite, calcium carbonate, calcium phosphate, kaolin, kaolinite, clay, talc, and oxidation are used in combination with the above non-particulate lubricant. Titanium, alumina, zirconia, aluminum hydroxide, etc. are added to the (A) layer and / or (B) layer in 0.01
In most cases, if the content is 0.5% by weight, the effect of the non-particulate lubricant can be synergistically enhanced.

[0086]

The following excellent effects can be obtained by the film for heat-sensitive stencil printing base paper of the present invention.

(1) It is possible to perform clear plate making and printing for both characters and solid printing. (2) With letter and solid printing, it is possible to perform plate making and printing without unevenness in thickness and unevenness in density. (3) The sensitivity and resolution are significantly improved.

In terms of productivity, the following effects can be obtained.

(4) The stretchability is excellent, and stable long-term film formation is possible. (5) A film having excellent slipperiness and winding property, capable of preventing wrinkles and astray winding, and having good flatness and thickness uniformity can be obtained.

Further, by laminating a release layer and a polymer layer having an oriented sulfonic acid group, (6) it is excellent in antistatic property, transparency and easy adhesion, and also excellent in antistick property.

[0091]

[Characteristic measuring method and evaluation method] (1) Melting energy [ΔHu (cal / g)] Determined from the area of the heat-sensitive film at the time of crystal melting using a DSC-2 type manufactured by PERKIN ELMER. The sample is 5 mg, and the heating rate is 10 ° C./min. This area is the area from the baseline to the absorption side by increasing the temperature, and the area until returning to the position of the baseline when the temperature is further increased, connecting the crystal melting start temperature position to the end position with a straight line, Determine the area (a). It is the value obtained by converting the area (a) into melting energy (cal) and dividing it by the sample weight (g).

(2) Crystal melting point [Tm (° C.)], glass transition temperature [Tg (° C.)] The temperature at which the peak of the crystal melting peak appearing during the measurement of ΔHu is Tm, and the temperature at which the baseline changes is T
g.

(3) Crystal melting half width [W _1/2 (° C.)] It is determined in the melting temperature range corresponding to 1/2 of the height of the crystal melting peak in the above ΔHu measurement.

(4) Center Line Average Roughness (Ra) Measured using a stylus type surface roughness meter according to JIS B0601. The cutoff is 0.25 mm and the measurement length is 4 mm.

(5) Maximum roughness (Rt) According to JIS B0601, it is measured using a stylus type surface roughness meter. It represents the distance between the largest peak and the deepest valley when measuring with a measurement length of 4 mm.

(6) Protrusion Diameter and Number of Protrusions A1 was vapor-deposited on the sample film at a heat of about 1000 Å to obtain an observation sample. This sample was magnified using a microscope (reflection method) and an image analyzing computer (manufactured by Cambridge Instrument Co., Ltd.), and the size of the projection (projection) was determined by an image with a contrast on the projection (magnification: 358 times). The diameter is represented by the diameter (equivalent circle diameter) when the area occupied by the protrusions is converted into a circle.

(7) Average particle size Inorganic particles are measured as ethanol slurry by using a stretching sedimentation type flow rate distribution measuring device CAPA-500 (manufactured by Horiba Ltd.).

(8) Evaluation of character printability JIS 1st level characters are used as a base paper (original) having a character size of 1.0 mm square, and the heat-sensitive stencil printing base paper of the present invention is "lithographic".
The 007D plate-making and printing machine (made by Riso Kagaku Kogyo Co., Ltd.) were used to make a plate, and the printed matter was evaluated as follows. Presence or absence of characters Characters that are clearly unusable in terms of presence or absence of uneven thickness of characters are marked with X, those that have no problems at all are marked with ○, and there are missing or uneven thickness but can be used Is indicated by a triangle.

(9) Evaluation of solid printability: (circle filled in black) 0.5, 1.
Using the base paper of 0, 3.0, 10.0 and 30.0 mmφ, the same plate-making and printing as in (8) is evaluated as follows. Correspondence with the base paper size of solid printing In the evaluation of the unevenness of light and shade of solid printing, those that are obviously unusable are marked with an X,
Those with no problem are shown with a circle, and those with a problem but usable are shown with a triangle.

(10) Evaluation of sensitivity Five types of pencil hardness of 5H, 4H, 3H, 2H, and H were prepared, and an original was prepared by writing characters with a pressing pressure of 50 g.
This manuscript is used to evaluate whether the character can be read. When written with 5H, the sensitivity becomes the thinnest, and the sensitivity becomes highest, and as H becomes higher, the black becomes darker and the sensitivity deteriorates.

(11) Stick Resistance The hot stick level when the heat sensitive film layer of the present invention was used as the thermal head side and pierced and run using Lithograph 007D manufactured by Ideal Science Industry Co., Ltd. was judged according to the following criteria. And, ◯ or more is considered good. ⊚: No sticking at all, normal perforation is possible, and running performance is extremely good. ◯: Normal perforation can be performed without any problem in running property, but some sticking occurs at the solid perforated portion. B: The vehicle runs, but normal perforation cannot be performed. ×: No running.

[0102]

EXAMPLES The present invention will now be described in more detail based on examples.

Example 1 Polyhexamethylene terephthalate (PHT) having an intrinsic viscosity of 1.0 was added with 2% by weight of silica having an average particle size of 0.4 μm so that the silica concentration was 0.25% by weight during melt extrusion. Blended into PHT. This is supplied to an extruder, melt-extruded from a T-die at 210 ° C., adhered to a rotating cooling roll (temperature 30 ° C.) by electrostatic force and cast, and this film is heated to 60 ° C. and longitudinally 2. It was stretched 8 times to obtain a uniaxially stretched film.

One side of this film was subjected to corona discharge treatment in an air atmosphere, and the treated surface was coated with a water-dispersed coating composition having the following composition by a gravure coating method.

[Coating composition] (a) Oxide wax 60 parts by weight (b) Vegetable wax 40 parts by weight {hydrogenated rosin / αβ-substituted ethylene (α-substituent: carboxyl, β-substituent: methyl) adduct} ・ alkyl (C6) poly (repeating unit: 5) ester compound of alcohol (c) turbine oil 5 parts by weight (d) polyethylene glycol oil 5 parts by weight (a) + (b) + (c) + (d) To make an aqueous dispersion, 1 part by weight each of nonionic surfactant, phosphoric acid ester, ammonium oleate, and 2-amino-2-methylpropanol was added, and the mixture was vigorously stirred in water, and further ultrasonically dispersed. An aqueous dispersion having a solid content ratio of 1.0% by weight was prepared.

The coated uniaxially stretched film was fed into a stenter heated with hot air at 80 ° C., stretched 2.8 times in the width direction, and then heat-treated at 140 ° C. in the stenter to give a base film thickness of 1.0 μm. , Coating layer thickness 0.04
A biaxially stretched film of μm was obtained. The center line average roughness Ra of the coating layer surface is 0.08 μm, and the maximum roughness Rt is 0.8 μm, 1 μm.
The number of protrusions of φ or more was 4800 / mm ² . Tm of the biaxially stretched film is 161 ° C., Tg is 45 ° C., W _1/2 is 6 ° C.,
ΔHu was 10 cal / g. The film thus obtained was laminated with Tetoron gauze, subjected to plate making and a printing machine, and its characteristics were evaluated. The results are shown in Table 2.

Comparative Example 1 A polyethylene terephthalate / isophthalate (80/20 mol%) copolyester having an intrinsic viscosity of 0.6 was used as a raw material. As the additive, silica was added in the same amount as in Example 1.
The content was 25% by weight. Extrusion temperature is 25 compared with Example 1.
0 ° C., longitudinal stretching temperature 85 ° C., widthwise stretching temperature 9
Example 1 except 0 ° C. and the heat treatment temperature changed to 200 ° C.
A film having a thickness of 1.0 μm was obtained in the same manner as in. Tm of this film is 205 ° C, Tg is 70 ° C, W _1/2 is 18
C, ΔHu is 5 cal / g, Ra is 0.08 μm, Rt
Was 0.75 μm, and the number of protrusions with a diameter of 1 μm or more was 4600 / mm ² .

[0108]

[Table 2]

Claims (7)

[Claims] 1. A biaxially stretched film having a crystal melting point Tm of 220 ° C. or lower, a glass transition temperature Tg of 0 ° C. or higher, and a crystal melting half-value width W _1/2 of 14 ° C. or lower is used. Characteristic film for heat-sensitive stencil printing base paper. 2. The melting energy ΔH of a biaxially stretched film
The film for heat-sensitive stencil printing base paper according to claim 1, wherein u is 3 to 12 cal / g. 3. The center line average roughness (Ra) of the surface of the biaxially stretched film is 0.05 to 0.3 μm, and the maximum roughness (Rt) is 0.5.
~ 4.0 μm and the number of protrusions with a diameter of 1 μm or more is 2,0
The film for base paper for heat-sensitive stencil printing according to claim 1 or 2, wherein the number is from 00 to 10,000 pieces / mm ² . 4. One side of the biaxially stretched film is dissolved in water,
A laminated film having a release layer containing, as a main component, a mixture of an emulsifying or suspending petroleum wax (A), a vegetable wax (B) and an oily substance (C), {(A) +
The weight ratio of (B)} / (C) is 100/1 to 1/1, and the center line average roughness Ra of the surface provided with the release layer is 0.03 to 0.1.
4. The film for heat-sensitive stencil printing base paper according to claim 1, wherein the release layer has a thickness of 4 μm and a thickness of 0.005 μm or more and Ra or less. 5. The film for heat-sensitive stencil printing paper according to claim 4, wherein the biaxially stretched film has a polymer layer having a sulfonic acid group oriented in at least the surface layer on the surface opposite to the release layer. 6. The biaxially stretched film is a biaxially stretched film obtained by peeling and separating from a laminated film with another thermoplastic polymer having excellent peelability. A film for heat-sensitive stencil printing base paper according to any one of the above. 7. The heat-sensitive stencil printing base paper film according to claim 1, wherein the biaxially stretched film is polyhexamethylene terephthalate and a copolymer thereof.