JPH04126293A - Laminated polyester film - Google Patents

Abstract

PURPOSE:To enhance the close adhesiveness of ink, printing sharpness, reelasability and sticking resistance by providing a layer based on a wax composition to at least one surface of a polyester film and providing projections having a specific shape to the surface of said layer. CONSTITUTION:In a laminated film, a layer based on a wax composition is provided to at least one surface of a polyester film and projections wherein the ratio of longitudinal direction/lateral direction is 3 or more are provided to the surface of said layer in density of 20/100mum<2>. In this case, the wax composition consists of petroleum wax and vegetable wax dissolved, emulsified or suspended in water and an oily substance dissolved, emulsified or suspended in water may be further added to the layer based on the wax composition so that the mixing wt. ratio of wax composition/oily substance becomes 100/1-1/1. When the ratio of the longitudinal direction/lateral direction of the projections is below 3, no smooth sliding is obtained and stickiness is partially generated according to circumstances. When the density of the projections is below 20/100mum<2>, the smooth running properties in a printer are not obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a laminated polyester film, and more particularly to a base film suitable for thermal transfer materials 1, thermal stencil printing base papers, and the like.

[Prior Art] In recent years, with the development of office automation, five types of various recording methods have been developed, but among them, the thermal recording method is attracting attention because it produces less noise during printing and is easy to operate. There is.

The thermal recording method uses a thermal recording device such as a thermal printer, brings the recording paper into contact with the thermal ink layer of the thermal transfer material, and selectively heats the film using a pulse signal from a heating head on the opposite side of the ink layer. As a result, the ink heated through the film melts or sublimates and is transferred to the recording paper. As this thermal transfer material, a thin plastic film is generally used in order to increase thermal efficiency.

However, in general, when a plastic film is used as a base film for a thermal transfer material, a phenomenon occurs in which a portion of the film is fused to the thermal head due to the amount of heat applied by the thermal head.

This phenomenon is called a stick phenomenon, and when this phenomenon occurs, not only does the thermal transfer material not run smoothly, but the problem arises that the thermal head is significantly contaminated and the sharpness of the print is impaired. In order to avoid this sticking phenomenon, it has been proposed to perform various surface treatments on the surface of the plastic film that comes into contact with the thermal head.

For example, silicone, melamine, phenol, epoxy,
Those with a heat-resistant protective layer such as polyimide (Japanese Unexamined Patent Application Publication No. 55
-7467 Publication), and one with a stick prevention layer made of a highly slippery inorganic pigment and a highly heat resistant resin (
(Japanese Patent Application Laid-open No. 155794/1983). In addition, there are those with a layer made of water-soluble or water-dispersible silicone and resin (Japanese Patent Application Laid-Open No. 192628/1982), and those with a layer made of water-dispersible fluororesin and water-based polymer (Japanese Patent Laid-Open No. 1982-192628). 6
0-192630), those coated or transferred with wax and/or liquid or paste substances at room temperature (JP-A-59-148697, JP-A-60-56)
No. 583).

However, with a heat-resistant protective layer, there is insufficient slippage with the head, so the running performance of the thermal transfer ribbon is poor in low-pulse width printers or platen-driven printers, resulting in uneven printing and, in extreme cases, the ribbon may stop running. There is.

In addition, those to which inorganic pigments are added have problems such as shortening the life of the head due to friction with the thermal head, and having a roughened surface that has poor thermal conductivity and makes clear printing difficult. Products made of laminated silicone resins or fluorocarbon resins tend to transfer these resins to the surface to which ink is applied after being wound onto a roll, resulting in problems such as repellency during ink application and poor ink adhesion. Ta.

A laminated film obtained by applying wax or the like to a plastic film and drying it has an excellent lubrication effect with the thermal head, but has the disadvantage that it does not easily slide on the fixed shaft of the printer, resulting in sticking. Was.

In addition, as a base paper for heat-sensitive stencil printing, a film made by bonding a film for base paper for heat-sensitive stencil printing and a porous support with an adhesive is usually used. , polypropylene film, and polyethylene terephthalate film have been used, but in recent years, in order to increase sensitivity, films have become thinner and JP-A-62-149469 and JP-A-63-312 have been used.
Improvements have been made in publications such as Publication No. 192. Furthermore, thin paper, polyester gauze, and the like have been used as porous supports.

When these laminates are overlaid with original documents with letters, figures, etc. written on them and irradiated with an infrared flash, the parts on which the letters, figures, etc. are written melt due to heat absorption and become perforated. This perforated base paper is used as a printing base plate.

Also, recently, perforation has been performed using a thermal printer. In this method, a thermal head is brought into contact with the film side, and printing energy is applied to perforate the film using the same principle as a normal thermal transfer method. Therefore, the flash irradiation method requires releasability from the original, and the latter thermal method requires stick resistance, similar to the above thermal transfer material.

However, when a plastic film is generally used as a film for thermal stencil printing, a sticking phenomenon occurs in some parts of the film due to the heat applied from the thermal head. Similar to the thermal transfer material described above, this phenomenon causes problems such as poor running properties of the film, contamination of the thermal head, and loss of sharpness during perforation. Furthermore, there is a problem that adhesion to the original occurs when punching with a flash lamp. For this reason, a release layer and a stick-resistant layer are provided, but when used for this purpose, they must be easily melted by heat. In extreme cases, the inconvenience of not perforating occurs.

[Problems to be Solved by the Invention] The object of the present invention is to avoid the above-mentioned drawbacks, that is, to avoid stickiness and to operate from low pulse width areas such as word processors, facsimiles, and barcode printers to high pulse widths such as video printers. A laminated layer for thermal transfer materials that has good runnability over a wide range of areas, extremely little head wear and head contamination, no repelling during ink application, and excellent ink adhesion and print clarity. The object of the present invention is to provide a laminated polyester film suitable as a laminated film for heat-sensitive stencil paper, which has good release properties, stick resistance, perforation properties, and excellent printing clarity, and is free from the above-mentioned drawbacks.

[Means for Solving the Problems] The present invention provides a laminated film having a layer containing a wax composition as a main component on at least one side of a polyester film, the layer surface having a layer in the length direction/width direction. Its main feature is a laminated polyester film characterized by having protrusions with a ratio of 3 or more at 20/100 μm2 or more.

The polyester film used in the present invention is a general term for polymer films having ester bonds as the main bonding chain of the main chain, but polyethylene terephthalate and polyethylene 2,6-naphthalate are particularly preferred as base films for thermal transfer materials. , polyethylene α,β-bis(2-chlorophenoxy)ethane 4.4. - dicarboxylate, polybutylene terephthalate, etc. Among these, polyethylene terephthalate film is the most preferable, considering quality, economical efficiency, etc. comprehensively. Therefore, hereinafter, the description will be made using polyethylene terephthalate film (hereinafter, polyethylene terephthalate film is abbreviated as PET film) as a typical example of polyester film as the base film for thermal transfer materials. Here, polyethylene terephthalate is one in which 80 mol% or more, preferably 90 mol% or more, and more preferably 95 mol% or more of ethylene terephthalate is a repeating unit, but within this limited amount range, the acid component and glycol component are Part of it may be replaced with a third component as described below.

Monoacid component monoisophthalic acid, 2.6-naphthalene dicarboxylic acid, 1,
5-naphthalene dicarboxylic acid, 2.7-naphthalene dicarboxylic acid, 4. 4. - Schiftyl dicarboxylic acid, 4
．． 4. -diphenylsulfonedicarboxylic acid, 4.
4. - diphenyl ether dicarboxylic acid, p-β-hydroxyethoxybenzoic acid, adipic acid, azelaic acid, sebacic acid, hexahydroterephthalic acid, hexahydroisophthalic acid, ε-oxycaproic acid, trimellitic acid, trimesic acid, pyromellitic acid, α,β-bisphenoxyethane-4,4-dicarboxylic acid, α,β-bis(2-chlorophenoxy)ethane-4,4°dicarboxylic acid, 5-sodium sulfoisophthalic acid, etc.

- Glycol components - propylene glycol, butylene glycol, hexamethylene glycol, decamethylene glycol, neopentylene gellicol, 1,1-cyclohexane dimetatool, 1,4-sochlorohexanedimethanol, 2,2-bis(4 -β-hydroxyethoxyphenyl)propane, bis(4-β-hydroxyethoxyphenyl)sulfone,
Diethylene glycol, triethylene glycol, pentaerythritol, trimethylolpropane, polyethylene glycol, polytetramethylene glycol, etc.

In addition, known additives such as heat-resistant stabilizers, oxidation-resistant stabilizers, weather-resistant stabilizers, ultraviolet ray absorbers, organic lubricants, pigments, dyes, organic or inorganic fine particles, fillers, and electrostatic charges are added to this PET. An inhibitor, a nucleating agent, etc. may be added. In particular, by adding inorganic and/or organic fine particles, the average surface roughness of the PET film after two-wheel orientation is 0.0.
When the thickness is 3 to 0.4 μm, preferably 0.05 to 0.2 μm, the running properties of the present invention can be further improved.

The intrinsic viscosity of the above PET (measured in orthochlorophenol at 25°C) is 0.40 to 1.20 dl/g, preferably 0.50 to 0.80 dl/g.

More preferably, those in the range of 0.5 to 0.75 dl/g are suitable for the content of the present invention.

The PET film is preferably biaxially oriented in terms of mechanical strength and dimensional stability. Biaxially oriented PET film (
(hereinafter abbreviated as PET-BO) is unstretched PET.
It is made by stretching a sheet by about 2.5 to 5.0 times in both the longitudinal and width directions, so-called biaxial directions, and shows a biaxial orientation pattern in wide-angle X-ray diffraction.

The thickness of PET-BO is not particularly limited, but when the laminated polyester film of the present invention is used as a base film for a thermal transfer material, the thickness is 0.5 μm or more and 30 μm or less, preferably 1
From the viewpoint of heat transfer properties and mechanical strength, it is preferable that the thickness is from μm to 10 μm.

In addition, when a polyester resin having a glass transition point higher than that of PET is laminated on at least one side of the PET film and then stretched, the film is less likely to wrinkle due to printing energy, so it is particularly preferable because the printing clarity is excellent. This laminated layer is preferably provided on the side that contacts the thermal head.

Polyethylene 2,6 naphthalate is a typical polyester having a glass transition point higher than that of PET.

In addition, a polyester film suitable for thermal stencil printing base paper preferably has a melting energy (ΔHu) of 3.
~1 lcal/g, more preferably 5-10 cal/g
It is desirable that Controlling ΔHu within this range is preferable because it improves the releasability from the original and the perforation performance.

Also, the difference (61 m) between the melting end temperature and the melting start temperature is preferably 50 to 100°C, more preferably 60 to 90°C.
It is desirable that By keeping this within this range, uneven shading and uneven thickness of characters during printing can be prevented, and clearer printing can be achieved.

Such polyesters can be controlled by copolymerization of various acid components and glycol components described in the section on PET films, such as copolymers of isophthalic acid, adipic acid, sebacic acid, diethylene glycol, etc.
Alternatively, a blend of these copolymers with PET may be used.

Furthermore, when used for this purpose, the base film is preferably biaxially stretched; a uniaxially stretched film or a non-stretched film tends to cause uneven perforation or to cause missing parts in printed products. Note that the degree of biaxial stretching is not particularly limited, but those with a plane orientation coefficient of 0.90 to 0.98 are particularly preferred.

In addition, the center line average roughness (Ra) is preferably 0°05 to 0.
．． 3 μm, more preferably 0.09 to 0°25 μm, and the maximum roughness (Rt) is preferably 0.5 to 4.0 μm
, more preferably 0.8 to 3.5 μm. By setting it within this range, even if the film is a thin film, there will be no creases and the like, improving winding properties and preventing a decrease in sensitivity due to opacity.

Furthermore, the number of protrusions with a diameter of 1 μm or more is preferably 2000 to 1.
0000 pieces/mm2. More preferably 2500-800
It is desirable that the number be 0 pieces/m m 2 because both slipperiness and transparency can be achieved. The number of protrusions with a diameter of 8 μm to 20 μm is preferably 20 to 1000/mm2. More preferably, the number is 50 to 800 pieces/mm2.

If it is less than 20 pieces/mm2, the film tends to meander.
If the number exceeds 1,000 pieces/m2, the film tends to break easily and productivity tends to decrease.

Furthermore, when used as a film for heat-sensitive stencil printing base paper, the heat shrinkage rate is preferably 10% or more, more preferably 20% or more within the range from the melting point of the film to the melting point -20°C, and preferably less than 10%. The plate-making sensitivity may be lowered, causing practical problems. Further, the heat shrinkage rate at 150° C. is more preferably less than 15%. When the present invention is used as a film for heat-sensitive stencil printing base paper, the thickness is not particularly limited, but is preferably 0.5 to 10 μm, and preferably 0.7 to 5 μm.
More preferably, the thickness is 0 μm. If the thickness becomes too thin, it tends to be unclear and uneven shading occurs, and if it becomes too thick, it tends to cause missing parts or uneven thickness.

In the present invention, in order to maintain the surface morphology of the polyester film when used as a film for heat-sensitive stencil printing base paper, that is, the surface roughness, the number of protrusions, and the number of protrusions within the above-mentioned preferred ranges, the polyester film subjected to extrusion in the production method described below It is desirable to create a master polymer containing inert particles in the resin and blend it with the main component polymer. In this case, the master polymer has a melting point of 10 to 10% higher than that of the main component polymer.
100°C, preferably 20 to 80°C higher, and/or
Or the intrinsic viscosity is 0. 2 to 1.0 higher is preferable.

Furthermore, it goes without saying that the specific surface morphology can be controlled to some extent by the shear stress during extrusion, the basis weight of the filter, extrusion conditions, etc. The inert particles used include elements from periodic table 1IA, IIIB,
IVA, IVB (7) Particles selected from elemental oxides or inorganic salts, such as calcium carbonate, wet silica (silicon dioxide), dry silica (silicon dioxide), aluminum silicate (kaolinite), obtained synthetically or as a natural product. ), barium sulfate, calcium phosphate, talc, titanium dioxide, aluminum oxide, aluminum hydroxide,
Examples include calcium silicate. The average particle diameter of the inert particles is preferably 0.1 to 3.0 μm. The amount added varies depending on the particle type and particle size, but it is 0.05
~2.0% by weight, preferably 0.1-1.0% by weight is preferred in order to obtain a specific surface morphology. Further, it is preferable to add an additive having an absorption peak in the wavelength range of the flash irradiation, since more clear perforation can be obtained.

The present invention provides a laminated film having a layer containing a wax composition as a main component on at least one side of the polyester film, the surface having a length direction/width direction ratio of 3.
The main point is to have at least 20 elongated protrusions/100 μm2. The term "main component" as used herein means that the spray amount ratio in the laminated composition is 50% or more, preferably 60% or more. The wax-based composition includes various commercially available waxes such as petroleum wax, vegetable wax, mineral wax, animal wax, and low molecular weight polyolefins, but is not particularly limited. In the present invention, petroleum-based waxes and vegetable-based waxes are preferably used from the viewpoint of stick resistance. Petroleum-based waxes include paraffin wax, microcrystalline wax, oxidized wax, and the like, and among these, oxidized wax is particularly preferred in terms of protrusion-forming properties. Examples of vegetable waxes include candelilla wax, carnauba wax, wood wax, olicurie wax, sugar cane wax, and rosin-modified wax, but compositions comprising the following compounds are particularly preferred in the present invention. That is, (rosin or disproportionated rosin, or hydrogenated rosin, α, β substituted ethylene (
α substituent: dicarboxyl, β substituent: hydrogen or methyl or carboxyl) adduct) ・Alkyl or alkenyl (each having 1 to 8 carbon atoms) poly(repeat unit = 1 to 6)
) It is preferable to use an ester adduct of alcohol in terms of slipperiness and mold releasability, and it is more preferable to use it in a mixed system with the above-mentioned oxidized wax. That is, the present invention is characterized in that fine elongated protrusions are formed by applying the composition and then stretching it in one direction.This invention is characterized by forming fine elongated protrusions in one direction after applying the composition. Wax dissolved, emulsified, or suspended in water is particularly preferred and commercially available.

The mixing weight ratio of petroleum wax/vegetable wax is 10
/90~90/10. Preferably 20/80 to 80/2
0, more preferably 30/70 to 70/30. The reason why the vegetable wax is 10% by weight or more is to provide easy slippage and mold release properties at high temperatures, and to obtain a uniform coating film with good uniform dispersibility when emulsified or suspended in water. By being suitable. . The reason why the content of petroleum wax is 10% by weight or more is that the coated film has good slipperiness due to the formation of protrusions and has good runnability during high-speed printing.

Further, in the present invention, when a mixture is prepared by further adding an oily substance to the above-mentioned wax-based composition, printing runnability in a high pulse width region can be particularly excellent. Here, the oil-like substance is an oil that is liquid or paste-like at room temperature, and includes vegetable oil, fat, mineral oil, synthetic lubricating oil, and the like. Vegetable oils include linseed oil, kaya oil, saffron oil, soybean oil, sinakiri oil, sesame oil, corn oil, rapeseed oil, bran oil, cottonseed oil, olive oil, sasanqua oil, camellia oil, castor oil, peanut oil, balm oil, and coconut oil. etc. Fats and oils include beef tallow, pork oil, rod oil, cacao oil, etc. Mineral oils include machine oil, insulating oil,
Examples include turbine oil, motor oil, gear oil, cutting oil, and liquid paraffin. As the synthetic lubricating oil, any synthetic lubricating oil that satisfies the requirements listed in the Chemical Encyclopedia (Kyoritsu Shuppansha) can be used, such as olefin polymerized oil, diester oil, polyalkylene glycol oil, silicone oil, etc. . Among these, mineral oils and synthetic lubricating oils, which have good running properties in the high pulse width region, are preferred. Alternatively, a mixture of these may be used.

It is preferable to add the oily substance in an amount of 1 to 100 parts by weight, preferably 3 to 50 parts by weight, per 100 parts by weight of the wax composition. If the amount of oily substances is less than 1 part by weight, the running performance in the high pulse width region such as in dye sublimation printers tends to deteriorate, and if it exceeds 100 parts by weight, the running performance in the low pulse width region tends to deteriorate. There is a tendency for sex to decline. When the above range is set, stickiness does not occur in printers with a wide range of pulse widths and the running properties are good, which is particularly preferable.

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

In addition, various additives such as dispersion aids, surfactants, preservatives, antifoaming agents, etc. may be added to the paint for the purpose of improving dispersibility in water and coating properties.

The centerline average surface roughness (Rat) of the surface provided with the layer (laminated film) containing the wax-based composition as the main component is 0°03 to 0.4
μm1 is preferably 0.05 to 0.2 μm, and the thickness of the laminated film is 0.005 μm or more.Ra
It is desirable that the thickness is less than l or more than 0.01 μm and less than Ral. Sticking tends to occur when the Ral of the laminated film is less than 0.03 μm or when the thickness of the laminated film is less than 0.005 μm, and when the thickness of the laminated film exceeds Ra1, there is a tendency for stickiness to occur during printing. There is a tendency for deterioration in performance and head contamination to occur. When Ral exceeds 0°4 μm, the stickiness is good, but the sharpness of the print tends to be poor.

Furthermore, by forming the special protrusions described below on the surface of the laminated layers, the present inventors have achieved extremely excellent stick resistance, runnability, and mold release properties that were previously unobtainable, as well as improved ink coating and adhesion properties. We have discovered an excellent layer. That is, in the present invention, 20/20 elongated protrusions with a length/width ratio of 3 or more are formed on the surface of the laminated film made of the above composition.
It is characterized by having a diameter of 100 μm or more, and the formation of this protrusion allows for smooth sliding on the fixed shaft of the printer during running, reduces frictional resistance in driving the platen roll, and makes running smooth. It is something to be done. In addition, since the protrusions are formed mainly from wax-based compositions or oil-like substances, they become molten when heated by a thermal head. Unlike protrusions made from inorganic particles, there is no intervening air, which has poor thermal conductivity, so the protrusions are extremely clear. Printing can be obtained. Therefore, the protrusion-forming film does not contain substances that do not melt with the heat of the thermal head, such as inorganic particles, and is formed from a wax composition or a mixture of it and an oily substance to prevent wear of the thermal head. This is particularly preferable in that it does so. Even if the composition is the same as that of the present invention, if these protrusions are not formed, stick will occur and the running properties of the film will be significantly impaired. The shape of the protrusion is preferably an elongated protrusion, and the length/width ratio is 3 or more, preferably 4 or more, and more preferably 5 or more. If the number of protrusions is less than 3, the sliding may not be smooth and stick may occur partially. The height of the protrusion is not particularly limited, but is 0.0
05 μm to 1 μm 1 preferably 0.01 μm to 0.5 μm
It is desirable that it be m. If the protrusion height is too high, the print clarity in the low pulse width region tends to decrease. The length of the protrusion is also not particularly limited, but is usually 0. The thickness is preferably about 1 μm to 2 μm. Also, the number of elongated protrusions is 20/10
0 μm2 or more, preferably 40 pieces/100 μm2. More preferably, it is necessary that 60 pieces/100 μm 2 or more are formed. Number of elongated protrusions is 20/100μm
If it is less than 2, slipperiness at room temperature will be poor and smooth running performance in printers will not be obtained. Also, this elongated protrusion is 1
Although it may be arranged in the same direction, it is better to arrange them randomly or intersect them from the viewpoint of running performance. A laminated polyester film with such elongated protrusions has an extremely smooth surface, and has good runnability in both high-speed printing and low-speed, high-pulse printing. Value at ℃65%RH (
μs+) is 0.3 or less, and the value at 100°C (
When the ratio (μs2/μs+) to μs2) is 1.0 or less, stick prevention properties and head contamination prevention properties are particularly excellent. Such slipperiness can be changed by the laminated thickness and the number of protrusions. That is, when the laminated thickness is too thin or when it is so thick that protrusion formation is insufficient, slipperiness tends to be insufficient.

To form more preferable protrusions, the lamination thickness should be 0°01
It is desirable that the thickness is 0.1 μm. In order to obtain the above-mentioned laminated film, it cannot be obtained by applying it to a biaxially stretched polyester film after crystal orientation, but it must be applied to a polyester film before crystal orientation, and after drying or while drying, stretching and heat treatment are required. This can only be obtained by a method that completes oriented crystallization. That is, the polyester film before crystal orientation is completed is stretched 2.5 to 5.0 times in the longitudinal direction, and then the surface to be coated is subjected to corona discharge treatment, and then applied to various coating devices such as a roll coater, a gravure coater, and a reverse coater. , coated using a kiss coater, bar coater, etc., and while drying or after drying, a coating of 2.5 to 5.0 in the direction perpendicular to the longitudinal direction.
Stretching is performed twice as much, and heat treatment is performed at 140 to 240°C if necessary. A laminated film having elongated protrusions can be obtained by the above method, but in order to form elongated protrusions arranged randomly, it is necessary to stretch with some moisture remaining before stretching or with humidification, and during heat treatment. It is important to provide some widthwise relaxation.

When the present invention is used as a film for heat-sensitive stencil printing base paper, by laminating the above-mentioned coating layer on the above-mentioned base polyester film, it has excellent stick resistance during perforation by the thermal method, and when irradiated with flash light. The laminated film can be made into a laminated film with excellent releasability from originals.

In addition, in this laminated film, a polymer having a sulfonic acid group and/or its salt is contained in the laminated film, or a polymer having a sulfonic acid group and/or its salt is contained on the opposite side to the side on which the laminated film is provided. This is particularly preferable since it has the effect of increasing antistatic properties and adhesion to the porous support by the adhesive by laminating such layers. Providing antistatic properties is effective in preventing repellency during ink application, preventing electrostatic adsorption of dust during the process, and preventing damage to the thermal head due to static electricity discharge. This polymer having a sulfonic acid group and/or its salt may be mixed into the wax-based composition and applied, or it may be provided separately from the wax-based composition layer on the opposite side, but the laminated film It is preferable that the sulfonic acid group and/or its salt be localized in a part (laminated film surface) farther from the polyester film than in a part closer to the polyester film in the thickness direction. Such sulfonic acid and/or its salt and localization can be obtained by following the method described in Japanese Patent Application No. 18140/1983.

Next, as a specific example of the method for producing a laminated polyester film of the present invention, a laminated polyester film for thermal transfer material will be explained as a representative example. PET containing so-called precipitated particles and inorganic particles (for example, silica with an average particle diameter of 1 μm) precipitated in the polymerization process is dried in a conventional manner, then melt-extruded, and the extruded sheet-like melt is cooled and solidified to produce unstretched PET. make a film. This film is 80-120
℃ and longitudinally 2. It is stretched 0 to 5.0 times to form a uniaxially oriented film. One side of this film is subjected to a corona discharge treatment in an air atmosphere, and a water-dispersed coating liquid containing a wax composition diluted to a predetermined concentration as a main component is applied to this treated side. This coated film is then heated to 90~
It is stretched 3 to 5 times in the width direction while heating to 140°C, and then introduced into a heat treatment zone at 140 to 240°C for 1 to 10 minutes.
Perform heat treatment for seconds. During this heat treatment, a relaxation treatment of 3 to 12% in the width direction may be performed as necessary. The film thus obtained is slit to an appropriate width to obtain a biaxially oriented laminated polyester film for heat-sensitive transfer materials. When this film is used as a heat-sensitive transfer material, it can be obtained by applying heat-melting or heat-sublimation ink to the non-laminated side and slitting the film to a desired width.

The thus obtained biaxially stretched laminated polyester film for heat-sensitive transfer materials can be used for various heat-sensitive transfer materials such as word processors, facsimiles, computer printers, video printers, bar code printers, and other types by providing an ink layer according to the application. It is used for printing out text or images using writers, plain paper copiers, etc.

[Method for Measuring Properties and Evaluating Effects] The methods for measuring properties and evaluating effects in the present invention are as follows.

(1) Protrusion formation on the laminated surface The surface of the laminated surface is photographed with an electron microscope at a magnification of 10,000 times or more, the shape of the protrusions is determined from the photograph, and the length (long direction) and width (short direction) of the elongated protrusions are determined. demand.

The number of elongated protrusions per unit area was determined from the photograph and converted to (pieces/100 μm2).

(2) Center line average surface roughness (Ra+) J I 5-
Measured according to BO601-1976. The cutoff value was 0.25 mm.

(3) Lamination thickness The cross section of the biaxially oriented polyester film provided with the coating layer was cut out and measured using an electron microscope photograph taken at a magnification of 100,000 times.

The thickness was taken as the average of the maximum thickness and the minimum thickness within one field of view, and the average value of 30 measurement points was taken as the lamination thickness.

(4) Coefficient of Static Friction The coefficient of static friction between soda glass (center line average roughness of 0.01 μm or less) and the laminated surface was measured using a TR type friction measuring machine manufactured by Toyo Seiki Seisakusho in accordance with ASTM-D1894. In addition, the static friction coefficient at 25°C and 60% RH is assumed to be μs1, and 10
The coefficient of static friction with soda glass heated to 0° C. was defined as μs2.

(5) Hot stick property-1 (Evaluation for use in thermal transfer materials) The following heat-melting ink was applied to a biaxially oriented polyester film on the opposite side to the laminated surface to a thickness of 3 to 4 μm using the hot-melt method, and heat-sensitive transfer was performed. I created the material.

[Heat-melt ink composition: 100 parts by weight of carnauba wax, 30 parts by weight of microcrystalline wax, 15 parts by weight of vinyl acetate-ethylene copolymer, 20 parts by weight of carbon black.Evaluation was carried out using Autonics thermal transfer printer BC-8MKII. head resistance 5
The pulse width is 0 by changing the applied voltage with a 00Ω thermal head.
．． Evaluation was made at the applied voltage level at which sticking did not occur when printing was performed at 5 m5 eC. An applied voltage of 8 cm or more was considered to have good stick resistance.

In addition, cases where stick occurred even under 8V were marked as [x]. Note that plain paper was used as the transfer paper.

(6) Hot stick property-2 (evaluation as a heat-sensitive transfer material) A sublimation ink of the following composition was applied to the opposite side to the laminated surface, and after drying, it was slit to an appropriate width to make a heat-sensitive transfer material. .

[Sublimation ink composition] ・Disperse dye KST-B-1364 parts by weight (manufactured by Nihon Kapaku ■) ・Ethyl hydroxyethyl cellulose 6 parts by weight ・Methyl ethyl ketone 45 parts by weight ・Toluene 45 parts by weight This thermal transfer material was applied to a sublimation printer (Sharp Color). Video printer G
Z-PIIW) was run under normal conditions of use and judged according to the following criteria.

◎: No stickiness at all and extremely good running performance.

○: There is no problem with running performance, and normal printing is possible, but a slight sticking sound occurs in the solid printing area.

△: Readable level.

×Nistic is extremely illegible.

■ Head contamination and abrasion (evaluation as a thermal transfer material) In (5) above, the applied voltage was 8 V and the pulse width was 0.5 m5.
After printing for 3000 m under EC conditions, the thermal head was removed and the contamination and wear conditions of the head were observed using a 100x optical microscope.

If the contaminated area of the head part was less than 30%, it was marked as [○], if it was 30% or more, it was marked as [x], and if it was less than 30% but could not be removed by wiping with ethyl alcohol, it was marked as [x]. The state of occurrence of scratches on the thermal head was also observed, and those with no scratches were marked as [○], and those with scratches were marked as [x].

(8) Inkability, ink adhesion (evaluation as a thermal transfer material) A biaxially oriented polyester film provided with a laminated film is overlaid with another polyester film so as to be in contact with the laminated film surface, and 0.5 kg is applied at 70°C. A load of /cm2 was applied and left for 24 hours. Next, peel off the two films and apply the above (
The ink of 5) was applied and the degree of repellency was observed. The ink was applied by a hot melt method, and the coating thickness was 3 to 4 μm.

Those with no repelling were rated as [○], and those with even slight repelling were rated as [×]. Also, when the ink layer is peeled off with a tape having an adhesiveness of 50 g/cm2, the peeled area is 20%.
The case where it was less than 20% was rated as [0], and the case where it was 20% or more was rated as [x].

(9) Antistatic super insulation resistance meter MODEL-VE-40 (Kawaguchi Electric Industry Co., Ltd.
The surface specific resistance was measured at an applied voltage of 100 V, 20° C., and 60% RH.

[Measurement and evaluation as a film for thermal stencil printing base paper] ■ Melting energy [ΔHu (cal/g)]
It was determined from the area of the film when it was melted using a DSC-2 model manufactured by PERKIN ELMER.

This area is the area that shifts from the baseline to the absorption side as the temperature rises, and returns to the baseline position as the temperature continues to rise.If you connect the melting start temperature position to the end temperature position with a straight line, Find (a). Same D
Indium was measured under SC conditions, and this area (b) was calculated as 6
．． It is determined by the following formula as 8 cal/g.

a/bx6.8 = ΔHu (cal/g) (11) Difference between melting end temperature and melting start temperature [ΔTm (°C)] The starting temperature is the melting starting temperature (T+'C)
and the temperature that returns to the baseline position is the melting end temperature (
It is calculated from the following formula as T2℃).

T2-T,=ΔTm('C) If it is difficult to determine the position of each baseline, draw a tangent to each line and find the temperature at which it begins to depart from this line and the temperature at which it returns.

Further, when ΔHu=Ocal/g, ΔHu is assumed to be infinite.

(12 Stick resistant laminated film and polyester gauze are laminated together, the surface with the laminated film is in contact with the thermal head, and the stick level is judged using the following criteria when perforating with a thermal printer. was rated as good.

◎: No sticking at all, normal drilling was possible, and the runnability was extremely good.

○: Normal perforation is possible with no problems in runnability, but some stickiness occurs in the solid printing area.

△: Runs but cannot perform normal drilling.

×: Not running at all.

(To) Release resistance Level of peeling resistance when the original is peeled off after overlapping the original and the surface with the laminated film of the same laminated product as in (2) above and performing perforation with infrared flash irradiation. was judged according to the following criteria, and 0 or more was considered good.

◎: Can be peeled off without any resistance.

○: There is some resistance, but the accuracy of the drilling part is maintained.

Δ: Can be peeled off, but the perforated portion is deformed and cannot be used as an original plate.

×: Cannot be peeled off, or the film or original is torn.

(14) Character printability evaluation Using JIS 1st standard characters as a manuscript with a character size of 2.0 mm square, a pasted product created in the same manner as in (2) above was printed using a “RISOGRAPH” 007D plate making printing machine (Riso Kagaku Industry (
The following evaluations were performed on the printed plates.

■Whether or not characters are missing.

■Is there any unevenness in the thickness of the characters?

Items that are obviously unusable in terms of ■ and ■ are shown as [x], items that have no problems at all are marked as [○], and items that are usable despite some missing parts or uneven thickness are marked as [△].

(6) Evaluation of solid printability Using a manuscript with a diameter of 1 to 5 mm and written with a circle filled with black inside, plate making and printing were carried out in the same manner as in (14) above, and the following evaluations were made. .

■Size compatibility between printed matter and manuscript.

■Is there any unevenness in the density of the printed matter?

Items that are clearly unusable are shown in ■ and ■, and items with no problems are shown as [○.2 Items that have problems but are at a usable level are shown as [△].

(Evaluation of IQ Sensitivity We prepared 5 types of pencil hardness: 5H, 4H, 3H, 2H, H, pressed with a pressure of 150g, used paper with letters on it as a manuscript,
This manuscript will be evaluated based on whether the characters are legible or not. If you can print a manuscript written in 5H, the sensitivity will be the best,
This means that the sensitivity decreases as the temperature increases.

[Example] Next, embodiments of the present invention will be described based on Examples.

Example 1 0.15% by weight of precipitated particles (particles precipitated during the polymerization process) with a particle size of 0.5 to 1.5 μm, and 1.5 μm in particle size
PET containing 0.2% by weight of calcium carbonate particles of
After sufficiently vacuum drying the pellets (intrinsic viscosity 0.63 dl/g), they were fed to an extruder and melted at 280°C to form a 10μ
After filtering through an m-cut metal sintered filter, it was extruded into a film through a T-shaped nozzle, and the film was wound around a cooling drum with a surface temperature of 30°C to cool and solidify. In order to improve the adhesion between the film and the surface of the cooling drum during this time, a wire electrode was placed on the film side and a DC voltage of 6 KV was applied. The thus obtained unstretched PET film was heated to 95°C.
The film was heated to 3° and stretched 5 times in the longitudinal direction to obtain a −axially stretched film. One side of this film was subjected to corona discharge treatment in an air atmosphere, and a water dispersion paint with the following composition was applied to the treated side using a gravure coating method to a coating thickness of 0.04 mm after two-wheel stretching.
It was coated in a thickness of μm.

[Coating composition (a) 100 parts by weight of vegetable wax (hydrogenated rosin, αβ-substituted ethylene (α substituent: carboxyl,
β substituent: methyl) adduct)・alkyl (number of carbon atoms: 6)
Poly(repeat unit = 5) alcohol ester compound In order to make the above (a) into an aqueous dispersion, a nonionic surfactant, phosphoric acid ester (butoxyethylated product), ammonium oleate, 2-amino-2-methylpropylene 1 part by weight of each tool was added, vigorously stirred in water, and an aqueous dispersion having a total solid content of 1.0 wt% was prepared using an ultrasonic disperser.

The coated uniaxially stretched film was guided into a tenter while being held with a clip, and after drying moisture in a preheating process at 110°C, it was stretched 4.5 times in the width direction while heating to 120°C, and then stretched at 225°C. Heat treatment was performed for 5 seconds to reduce the lamination thickness to 0.
A laminated polyester film having a laminated surface roughness of 0.04 μm and a thickness of 5 μm per film was obtained. On the surface of the laminated film of this film, 48 fine elongated protrusions with a length/width ratio of 3 or more were formed/100 μm2.

Table 1 shows the results of evaluating this laminated polyester film as a thermal transfer material. This laminated polyester film did not repel during inking and had good adhesion. In addition, there was no stickiness during the printing run test.
Moreover, there was no head contamination or head wear.

Example 2 A paint with a total solid content of 1.0 wt% was prepared by adding the same amount of oxidized wax as the vegetable wax to the paint composition of Example 1. A laminated polyester film was prepared in the same manner as in Example 1 using this paint. The roughness of this laminated surface was 0.08 μm, the laminated thickness was 0.04 μm, and 75 fine elongated protrusions with a length/width ratio of 3 or more were formed on the laminated surface. Table 1 shows the results of evaluating this laminated polyester film as a thermal transfer material.

Comparative Example 1 Biaxially oriented P with a thickness of 5 μm and a center line average roughness of 0.08 μm
One side of the ET film was subjected to corona discharge treatment, and the coating solution of Example 1 was applied to the treated side using a gravure coater to a coating thickness of 0.04 μm.
A laminated polyester film was prepared by drying for minutes.

No elongated protrusions were formed on the surface of the laminated film of this film, and as a result of evaluation as a thermal transfer material, significant stickiness occurred.

Comparative Examples 2 to 3 Laminated polyester was prepared in the same manner as in Example 1, except that the coating composition in Example 1 was an aqueous solution or aqueous dispersion of polyether-modified silicone (Comparative Example 2) and fluorine-modified acrylic resin (Comparative Example 3). Got the film. As a result of evaluating this laminated polyester film as a thermal transfer material, it was found that ink repellency was significant and ink adhesion was poor.

Example 3 A laminated polyester film was obtained in the same manner as in Example 2 except that the following (c) and (d) were added to 100 parts by weight of the solid content of the coating composition.

(C) Turbine oil 5 parts by weight (d) Polyethylene glycol oil 5 parts by weight (c) and (d)
) to prepare an aqueous dispersion having a total solid content of 1% by weight in the same manner as in Example 2.

The laminated film surface of the obtained laminated polyester film has 103/100 protrusions with a length/width direction ratio of 5 or more.
When this was evaluated as a heat-sensitive transfer material, it showed extremely excellent printing runnability, especially in a high pulse width sublimation printer.

Comparative Example 4 The paint of Example 2 had an average particle size of 0. A laminated polyester film was prepared in the same manner as in Comparative Example 1 except that 5% by weight of 5 μm silica was added as a solid content. The surface of this laminated film has 63/1 particle protrusions (length/width ratio 1-2).
00 μm2 was formed. As a result of evaluating this laminated polyester film as a heat-sensitive transfer material, sticking occurred because the shape of the protrusions was different from that of the present invention even though protrusions were formed.

Example 4 A laminated polyester film was prepared in the same manner as in Example 1, except that the same coating composition as in Example 3 was used, and after coating, the coating film was dried and then stretched without moistening with steam. Similar to Example 2, elongated protrusions were formed on the surface of this laminated film, but the arrangement was random, and the protrusions were crossed or bent. This laminated polyester film had excellent slipperiness and good properties as a heat-sensitive transfer material.

Comparative Examples 5 to 6 A laminated polyester film was obtained in the same manner as in Example 1 except that the concentration of the coating material and the laminated thickness were changed. As the thickness of the laminated film increases, the protrusion formation property on the surface of the laminated film changes, and those with the number of protrusions and the form of the protrusions outside the scope of the present invention have poor slipperiness, and as a result of evaluation as a thermal transfer material, sticking occurred.

Example 5 A polyethylene terephthalate/isophthalate (85/15 mol%) copolymer with an intrinsic viscosity of 0.6 and an average particle size of 0.
Intrinsic viscosity 0.6 with 2% by weight of 1 μm silica particles added
Polyethylene terephthalate was blended so that the silica particle concentration after melt extrusion was 0.25% by weight.

After thoroughly drying this in vacuum, it was fed to an extruder and
It was melt-extruded through a T-type nozzle at 30° C. and wound around a rotating cooling roll at 30° C. to cool and solidify to obtain an unstretched film. This film was heated to 90° C. and stretched 4.0 times in the longitudinal direction to obtain a uniaxially stretched film. One side of this -axially stretched film was subjected to corona discharge treatment in an air atmosphere, and the same coating material as in Example 2 was applied to the treated side using a gravure coating method to the same thickness. The coated film was held in a clip and introduced into a tenter heated with hot air at 90°C, and after drying moisture, it was stretched 3.5 times in the width direction, and then stretched to 16
Heat treated at 0°C, base film thickness 2. A laminated polyester film having a thickness of 0 μm and a laminated film thickness of 0604 μm was obtained. On the surface of this laminated film, 82 elongated protrusions/100 μm2 with a length/width ratio of 3 or more were formed. The non-laminated side of this film and polyester gauze were bonded together with an adhesive and evaluated as a base paper for heat-sensitive stencil printing.

The results are shown in Table 2.

Example 6 A laminated polyester film was produced in the same manner as in Example 5 except that the coating composition was the same as in Example 3. As a result of evaluating this film as a thermal stencil printing base paper, it showed extremely excellent properties as shown in Table 2.

Comparative Examples 7-8 A laminated polyester film was obtained according to Example 5 except that the coating composition was the same as Comparative Examples 2-3. 1. No elongated protrusions were formed on the surface of the laminated film of this film.
As a result of evaluation as a thermal stencil printing base paper, the silicone-coated product (Comparative Example 7) had a good release effect upon flash irradiation, but sticking occurred when using the thermal method. Furthermore, when a fluorine-modified acrylic resin was used, the mold releasability, stick resistance, and printability were unsatisfactory.

Comparative Examples 9 to 10 A biaxially oriented polyester film (thickness: 2 μm) of Example 5 without a laminated film was prepared, and a laminated polyester film was obtained on one side in the same manner as in Comparative Examples 1 and 4.

As shown in Table 2, the cases in which no protrusions were formed (Comparative Example 9) and those in which the protrusion shape was not within the scope of the present invention (Comparative Example 10) were unsatisfactory as thermal stencil printing base papers.

[Effects of the Invention] The present invention is a laminated film having a layer containing a wax composition as a main component on at least one side of a polyester film, and by forming special protrusions on the surface of the laminated film, thermal transfer materials can be produced. It has the following excellent properties when used as a substrate film for printing or as a film for heat-sensitive stencil printing base paper.

■There is no stick when printing.

■Good adhesion with no repelling during inking.

■Less contamination of the thermal head and no wear.

It also has the following excellent properties when used as a film for heat-sensitive stencil printing base paper.

■Excellent releasability from originals after flash irradiation.

■Stick does not occur when drilling using the thermal method.

■Good drilling accuracy, Can print clearly.

Hei 2-173304 Hei 2-173305

Claims (6)

[Claims] (1) A laminated film having a layer containing a wax-based composition as a main component on at least one side of a polyester film, wherein the layer surface has 20/20 protrusions with a length/width ratio of 3 or more. A laminated polyester film characterized by having a thickness of 100 μm^2 or more. (2) The laminated polyester film according to claim (1), wherein the wax composition is a petroleum wax and a vegetable wax that are dissolved, emulsified, or suspended in water. (3) The layer containing the wax-based composition as a main component further contains an oil-like substance that dissolves, emulsifies, or suspends in water, and the wax-based composition/oil-like substance mixture weight ratio is 10.
The laminated polyester film according to claim 1 or 2, characterized in that the ratio is 0/1 to 1/1. (4) A layer containing a wax-based composition as a main component is applied to the surface of the polyester film before crystal orientation is completed, and then dried, stretched, and heat treated to complete the oriented crystallization. The laminated polyester film according to any one of claims (1) to (3). (5) The static friction coefficient between the surface of the layer containing the wax composition as a main component and the soda glass at 25°C and 65% Rh (μs_1) is 0.3 or less, and at 100°C
The ratio of the value (μs_2) and (μs_1) in (μs_
2)/(μs_1) is 1.0 or less, the laminated polyester film according to any one of claims (1) to (4). (6) The polyester film is a biaxially stretched film, and the melting energy of the film is 3 to 11 cal/
g, the difference between the melting end temperature and the melting start temperature is 50 to 100 °C
The laminated polyester film according to any one of claims (1) to (5).