JP2002011970A - Base film for heat sensitive transfer ribbon - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a film difficult to be broken in a step of forming a film or processing the film and having excellent productivity and to provide a film having excellent printing stability in the case of using for a heat sensitive transfer ribbon. SOLUTION: In a base film for the heat sensitive transfer ribbon, a biaxially stretched film made of polyester is chacaterized in that the specification for the number of flies having a mean diameter exceeding 90 μm of 5 pieces/m2 or less, and an intrinsic viscosity is 0.40 to 0.90 dl/g.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a base film for a heat-sensitive transfer ribbon, and more particularly to a base film for a heat-sensitive transfer ribbon which can reduce the frequency of film breakage in a film forming process or a film processing process, has excellent productivity, and has a high productivity. The present invention relates to a base film for a thermal transfer ribbon having excellent printing stability, and particularly to a film suitable for a thermal transfer ribbon.

[0002]

2. Description of the Related Art Thermal transfer recording systems include a heat-melt transfer recording system and a sublimation transfer recording system. In each case, a higher printing speed has been demanded in recent years. To increase the printing speed, it is necessary to reduce the thickness of the base film in order to efficiently transfer heat from the thermal head during printing.

Conventionally, as a polyester film used in a ribbon for a thermal transfer printer, a polyester film having a specified surface roughness (Japanese Patent Application Laid-Open No. 62-299389) or a material having a specified material and a Young's modulus in a longitudinal direction (Japanese Patent Application Laid-Open No. 62-299389). 62-11
1719), which specifies the change in temperature in the transverse direction of a biaxially oriented polyester film (Japanese Unexamined Patent Publication No.
No. 41297) is known.

However, it has been found that simply reducing the thickness of these films by a conventional film forming method causes the following problems. That is, in the film forming process and the processing process, there is a problem that the film is frequently broken due to the foreign matter inside the film as a starting point. Further, when a large amount of large foreign matter is present, there is a problem that clear printing cannot be performed when printing is performed using the thermal transfer ribbon made of the film.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems of the prior art and to provide a film which is hardly broken in a film forming process or a film processing process and which is excellent in productivity. Another object of the present invention is to provide a film having excellent printing stability when used for a thermal transfer ribbon.

[0006]

The present invention is directed to a biaxially oriented film made of polyester, wherein the number of fly specs having an average diameter of more than 90 μm is 5 /.
m ² or less, and a base film for thermal transfer ribbon, wherein the intrinsic viscosity is less than 0.40 dl / g or more 0.90 dl / g. The polyester is preferably polyethylene-2,6-naphthalate or polyethylene terephthalate.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail. Polyester The polyester constituting the film of the present invention is a saturated polyester obtained by polycondensing a dicarboxylic acid component and a diol component. Representative examples of the saturated polyester include polyethylene terephthalate and polyethylene-2,6-naphthalate. Such a polyester may be a homopolymer or a copolymer. In the case of a copolymer, a main dicarboxylic acid component,
The proportion of the copolymerization component other than the diol component is preferably not more than 20 mol% based on the total dicarboxylic acid or the total dicarboxylic acid, since the inherent properties of the polyester are not remarkably lost. Examples of the copolymer component other than the main dicarboxylic acid component and the diol component include the following having two ester-forming functional groups.

For example, oxalic acid, adipic acid, phthalic acid, sebacic acid, dodecanedicarboxylic acid, succinic acid, isophthalic acid, 5-sodium sulfoisophthalic acid, terephthalic acid, 2-potassium sulfoterephthalic acid, 2,7-
Naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, 4,4 ′
Diphenyldicarboxylic acid, phenylindanedicarboxylic acid, diphenyletherdicarboxylic acid and lower alkyl esters thereof; oxycarboxylic acids such as p-oxyethoxybenzoic acid and lower alkyl esters thereof; propylene glycol, 1,2-propanediol, 3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,2-cyclohexanedimethanol, 1,3-
Cyclohexanedimethanol, 1,4-cyclohexanedimethanol, p-xylylene glycol, ethylene oxide adduct of bisphenol A, bisphenol S
Of ethylene oxide, triethylene glycol, polyethylene oxide glycol, polytetramethylene oxide glycol, neopentyl glycol and the like.

Further, the polyester of the present invention may be one in which a terminal hydroxyl group and / or a carboxyl group is partially or entirely blocked with a monofunctional compound such as benzoic acid or methoxypolyalkylene glycol.
Alternatively, it may be modified with an extremely small amount of an ester-forming compound having three or more functions such as glycerin and pentaerythritol within a range where a substantially linear polymer can be obtained. Furthermore, a composition in which different kinds of polyesters are blended may be used.

Fly Specs In the film of the present invention, the number of fly specs having an average diameter exceeding 90 μm is 5 / m ² or less, preferably 3 / m ² or less.
Pcs / m ² or less, more preferably 0 pcs / m ² . Here, the fly specification is a phenomenon in which coarse particles and foreign substances contained in additives (lubricants, etc.) contained in a polymer are generated as nuclei. It is composed. If the fly specification is large or the frequency of occurrence is high, the range of thin polymer film is widened, so there is a sudden fluctuation in temperature and tension during film formation, slitting, and processing as a ribbon. In this case, the film is broken due to stress concentration, and the productivity is reduced. Even if the film is not broken, if there is a fly spec outside the above range, the printing of the corresponding portion becomes unclear during printing.

In order to keep the number of fly specs in the above-mentioned range, it is preferable to use a non-woven fabric type filter having an average opening of 10 to 40 μm, preferably 15 to 35 μm, made of a stainless steel fine wire having a wire diameter of 15 μm or less, as a filter at the time of film formation. preferable. If the opening of the filter exceeds 40 μm, there is no effect of reducing coarse particles in the molten polymer, while if the opening is less than 10 μm, the filter is liable to be clogged, and it is difficult to commercialize the filter industrially. There are other filters using mesh structure or sintered metal, etc.,
There are problems such as a shorter life and a slightly lower filtration efficiency as compared with a non-woven filter. Further, in order to more effectively bring the number of large-sized fly specs into the above-mentioned range, it is preferable to add the lubricant itself to the polymer after previously filtering the lubricant with a filter having a predetermined opening.

Additives In the film of the present invention, additives such as stabilizers, dyes,
An ultraviolet absorber, a flame retardant and the like can be contained for the purpose so that the fly specification and the intrinsic viscosity do not deviate from the range specified in the present invention. Further, in order to provide the film with preferable slipperiness, it is preferable to contain a small amount of inert particles. Such inert particles include, for example, spherical silica, porous silica, calcium carbonate, silica alumina, alumina, titanium dioxide, kaolin clay,
Examples include inorganic particles such as barium sulfate and zeolite, or organic particles such as silicon resin particles and crosslinked polystyrene particles. The inorganic particles are preferably synthetic products rather than natural products for reasons such as uniform particle size, and inorganic particles of any crystal form, hardness, specific gravity, and color can be used. The average particle diameter of the inert fine particles is preferably in the range of 0.05 to 5.0 μm,
More preferably, the thickness is 0.1 to 3.0 μm. The content of inert fine particles is preferably from 0.001 to 1.0% by weight, more preferably from 0.1 to 0.5% by weight. The inert particles to be added to the film may be a single component selected from those exemplified above, or a multi-component containing two or more components.

Inherent Viscosity According to the study of the present inventors, as a measure to keep the number of fly specs in the above-mentioned range, at the time of film formation, a molten polymer is mixed with a stainless steel fine wire having a wire diameter of 15 μm or less with an average opening of 10 to 10 μm. It has been found that filtration is carried out with a nonwoven fabric type filter of 40 μm, preferably 15 to 35 μm. But,
When the molten polymer is filtered with such a fine opening filter, if the viscosity of the molten polymer is high, a large pressure is required to filter at a constant flow rate, and as a result, the flow rate can be increased to a certain value or more. There was a problem that it became difficult and the productivity could not be increased. Therefore, in order to improve productivity in a production facility having the above-mentioned filtration step, it is necessary to lower the viscosity of the molten polymer, that is, to lower the intrinsic viscosity of the film. However, if the viscosity of the molten polymer is too low, that is, if the intrinsic viscosity of the film is too low, the film becomes brittle, resulting in film breakage, and consequently reducing the productivity of the film. .

The inventors of the present invention have studied to solve such contradictory problems. As a result, by setting the intrinsic viscosity of the film to a specific range, the flow rate of the molten polymer is not reduced, and the film is not broken. As a result, they found that productivity was improved.

That is, the film of the present invention has an intrinsic viscosity of 0.40 dl / g or more and 0.90 dl / g or less. Preferably 0.45 dl / g or more and 0.70 dl / g or less,
More preferably, it is 0.50 dl / g or more and 0.60 dl / g or less. If the intrinsic viscosity is less than 0.40 dl / g, the film becomes brittle, and it is not preferable because the film easily breaks during film formation or breaks during the ribbon processing step. The intrinsic viscosity of the film is 0.9
If it exceeds 0 dl / g, it is necessary to increase the intrinsic viscosity of the polymer considerably, and it is not preferable because it takes a long time for polymerization in a usual synthesis technique, and it also requires difficulty in filtering a molten resin with a filter.

Film Thickness The thickness of the film used in the present invention is preferably 0.5 to 10 μm. When the thickness exceeds 10 μm, it takes a long time for heat conduction, which is not suitable for high-speed printing. Conversely, the thickness is 0.5μ
If it is less than m, the mechanical strength is low and the workability is poor. Further, the strength required as a ribbon is inferior and is not preferred.

Easy Adhesion Layer By providing a thermal transfer ink layer on one or both sides of the film of the present invention, a thermal transfer ribbon can be manufactured. Between the film and the thermal transfer ink layer, a coating layer made of at least one water-soluble or water-dispersible resin selected from the group of urethane, polyester, acrylic, and polyester modified with a vinyl resin may be provided. it can. This coating layer is preferably provided in order to enhance the adhesiveness between the heat-sensitive transfer ink layer composed of the dye and the resin binder and the polyester film. In addition, as the inorganic fine particles in the coating layer, silica, silica sol, alumina, alumina sol, zirconium sol, kaolin, talc, calcium carbonate, calcium phosphate, titanium oxide,
Barium sulfate, carbon black, molybdenum sulfide, antimony oxide sol, and the like, as organic fine particles, may contain crosslinked polystyrene, crosslinked polyethylene, polyamide, polyester, polyacrylate, epoxy resin, silicone resin, fluororesin, and the like. . Further, if necessary, an antifoaming agent, a coating improver, a thickener, an antistatic agent, an organic lubricant, an antioxidant, a foaming agent, a dye, a pigment and the like may be contained. This coating liquid is preferably applied to one or both surfaces of the film before the crystal orientation is completed in the film production process. Coating may be performed separately from the film manufacturing process, but in this case, dust and dirt are likely to be involved, and that portion becomes a defect at the time of printing, and a clean atmosphere is desirable. From these points, coating during the manufacturing process is preferable.
At that time, the solid content concentration of the coating solution is usually 0.1 to 30% by weight, more preferably 1 to 10% by weight. The coating amount is preferably 0.5 to 50 g per 1 m ^{2 of the} running film. A known method can be applied as a coating method. For example, roll coating, gravure coating, roll brushing, spray coating, air knife, impregnation,
The curtain coating method or the like may be applied alone or in combination.

Method for Producing Film The film of the present invention is obtained by melting a polyester obtained by a usual method at (Tm) ° C. to (Tm + 70) ° C. (Tm indicates a melting point), a nonwoven fabric, a sintered metal, a network structure, Filter using a filter consisting of stainless steel fine wire. Immediately thereafter, the unstretched film that has been closely contacted and cooled and solidified on the casting drum cooled from the die slit is biaxially stretched and thermally fixed. Further, it can be produced more advantageously by performing a relaxation or tension treatment during heat setting. For example, the unstretched film is set to Tg to (Tg + 6
0) biaxially stretching at a temperature of 2.0 ° C. (Tg indicates a glass transition temperature) at a magnification of 2.0 to 6.0 times in the machine direction and the transverse direction;
g + 60) .degree. C. to (Tg + 120) .degree.
Heat set for 00 seconds. In the heat setting, it is desirable that the zone is divided into two or more, preferably four or more, because the temperature can be controlled for each zone. Stretching can be performed by a commonly used method, for example, a method using an IR heater, a method using a roll, or a method using a tenter, and may be simultaneously stretched in the vertical and horizontal directions, or may be sequentially performed in the vertical and horizontal directions. You may. In the case of further performing the relaxation treatment, the relaxation treatment is performed until the film is wound around the roll after the heat fixing. The relaxation treatment method is to reduce the tenter width in the middle of the heat fixing zone and reduce the relaxation by 0 to 3% in the film width direction. A method of performing the treatment, a method of separating both ends of the film, and reducing the take-off speed with respect to the supply speed of the film under a temperature condition not lower than the melting temperature of the film and not higher than the melting temperature. A method of heating, a method of transporting the film on the heating transport roll and a method of reducing the speed of the transport roll after the heating transport roll, and a method of transporting the film over a nozzle that blows out hot air after heat fixing, while taking up the supply speed more than the supply speed. A method of reducing the speed, or after winding the film with a film forming machine, transport the film onto a heated transport roll and reduce the speed of the transport roll. There are methods or the roll speed after the heating zone while conveying the heated zone by the heating oven or IR heaters decelerates from the roll speed before the heating zone,
Either method may be used, and the relaxation process is performed with the deceleration rate of the take-up speed relative to the supply-side speed being 0.1 to 3%. Further, it is preferable that the processing is performed in the heat fixing zone where the temperature is the highest, in order to form the dimensionally stable structure.
If necessary, a cooling zone can be provided to cool the film to a temperature around Tg ± 40 ° C. Thereby, it becomes a flat film with little unevenness of thickness, which is preferable. Further, depending on the purpose, an easy-contact layer, an anti-fusing layer and the like can be provided after unstretched or longitudinally stretched. These layers may be provided after being wound once as a biaxial film.

Thermal Transfer Ink Layer In the present invention, the thermal transfer ink layer is not particularly limited, and a known one can be used. That is, a binder component, a coloring component, and the like are used as main components, and a softener, a plasticizer, a dispersant, and the like are added in appropriate amounts as needed. Specific examples of the main component, as a binder component, carnauba wax, known waxes such as paraffin wax and celluloses, polyvinyl alcohols, polyvinyl alcohol partially acetalized product,
Polyamides, various high-melting polymer materials and the like are used,
As the colorant, carbon black is mainly used, and other various dyes or organic or inorganic pigments are used. In addition, the thermal transfer ink layer may include a sublimable dye. Various disperse dyes and basic dyes can be used as the sublimable dye. As a method of providing the heat-sensitive transfer ink layer on the surface of the easy-adhesion layer of the base material layer, a known method, for example, hot melt coating, gravure with a solvent added, reverse, a solution coating method such as a slit die method or the like is used. be able to.

In order to prevent sticking of the thermal head portion, a surface of the film of the present invention on which the thermal transfer ink layer is not provided is preferably a polyol, for example, a polyalcohol and a polyisocyanate compound and a phosphate polyester compound. Is formed. Examples of such a polyalcohol include a polyvinyl butyral resin having a hydroxyl group, a polyester resin, a polyether resin, a polybutadiene resin, an acrylic polyol, a nitrocellulose resin, a cellulose acetate resin, a cellulose acetate resin,
It is preferably used from urethane and epoxy prepolymers. Further, the provision of the anti-fusing layer may be performed after unstretching or longitudinal stretching, or after once winding as a biaxial film. This is preferable because the thermal history applied to the base from the thermal head after processing into the transfer ribbon can be reduced.

[0021]

The present invention will be further described with reference to the following examples. The characteristics in the examples were measured by the following methods.

(1) Fly Spec The film surface is subjected to polarized light transmission illumination using a universal projector with a 50
After observing and marking the fly specs existing in the measurement area of 1 m ² and further observing each fly spec with an optical microscope, the average diameter including the voids generated in the nuclei of the fly spec and its periphery ( (Maximum diameter + minimum diameter) / 2) was calculated, and the number exceeding 90 μm was counted.

(2) Intrinsic viscosity Measured at 25 ° C. using o-chlorophenol as a solvent.

(3) Film-forming properties The film-forming properties at the time of film formation were evaluated according to the following criteria. ：: Very stable film formation without breakage. (Break frequency: once or less per day) △: Break sometimes occurs and film formation is unstable. (Breaking frequency: 2 to 5 times a day) ×: Breaking occurs frequently, and substantially stable film formation is impossible. (Breaking frequency 6 times or more per day)

(4) Printability A thermal transfer ribbon is manufactured from the formed film, and a printer Hitachi VY-200 (Hitachi, Ltd.) is attached to an image receiving sheet VY-200 (a standard paper product name, manufactured by Hitachi, Ltd.). The product was printed so that the optical density became maximum. The printability of the produced thermal transfer ribbon was evaluated according to the following criteria. ：: clear printing ×: uneven printing density, unclear

Example 1 Dimethyl terephthalate 100
To a mixture of 60 parts by weight of ethylene glycol, 0.024 part of manganese acetate tetrahydrate was added.
The transesterification reaction was performed while gradually raising the temperature to 40 ° C. On the way, when the reaction temperature reached 170 ° C., 0.019 parts of antimony trioxide was added, and 0.3% by weight of spherical silica fine particles were further added. Subsequently, a transesterification reaction was carried out, and after the transesterification reaction was completed, trimethyl phosphate was dissolved in ethylene glycol at 135 ° C. for 5 hours at 0.11 to 0.11.
A solution heat-treated under a pressure of 0.16 MPa (0.018 parts in terms of trimethyl phosphate) was added. Thereafter, the reaction product was transferred to a polymerization reactor, and the temperature was raised to 290 ° C.
The polycondensation reaction is carried out under a high vacuum
A polyester having an intrinsic viscosity of 0.62 as measured with an o-chlorophenol solution at ℃ was obtained. The polymer was filtered through a nonwoven fabric filter having an opening of 25 μm, melted and extruded into a sheet by a T-die, and placed on a water-cooled casting drum.
It was adhered at a speed of 7.5 m / min and solidified by cooling to obtain an unstretched sheet. This unstretched film is stretched by a high-speed roll in the machine direction (machine direction) at 150 m / min by roll stretching.
The film was stretched 4.5 times at 105 ° C. On the side of the longitudinally stretched film where the ink layer is not applied, a coating of the following composition 1 is applied as a fusion preventing layer with a gravure coater so that the coating thickness after drying is 0.5 μm. Was coated with a gravure coater on the side to be coated with a coating composition of the following composition 2 as an easy-adhesion layer so that the coating film thickness after drying was 0.1 μm.
Thereafter, the film is successively biaxially stretched 3.8 times in the transverse direction (width direction) at 110 ° C., and heat-fixed at 210, 220, 180, and 90 ° C. for 2 seconds in the first, second, and third heat fixing and cooling zones, respectively. After cooling, a 2% tension treatment was performed in the width direction in the second heat setting zone to obtain a biaxially oriented film having a thickness of 4.0 μm.

Coating composition 1 Acrylic acid ester 14.0% by weight Amino-modified silicone 5.9% by weight Isocyanate 0.1% by weight Water 80.0% by weight

Composition 2 (acrylic + polyester +
Epoxy) The composition of the coating material 2 is as follows. The acrylic resin is composed of 65% by mole of methyl methacrylate / 28% by mole of ethyl acrylate / 2% by mole of 2-hydroxyethyl methacrylate / 5% by mole of N-methylolacrylamide. The solid content is 42% by weight, and the polyester resin is an acid component. 35 mole% terephthalic acid / mole isophthalic acid 1
It is composed of 3 mol% / 5 mol sodium 5-sodium sulfoisophthalic acid, 45 mol% of ethylene glycol as a glycol component / 5 mol% of diethylene glycol, a solid content of 42 wt%, and N, N,
N ', N',-tetraglycidyl-m-xylylenediamine is 6% by weight on a solid basis, and lauryl polyoxyethylene as a wetting agent is 10% by weight on a solid basis.

Fly specs and intrinsic viscosities of the obtained biaxially oriented polyester film were determined. Next, a coating liquid for an ink layer having the following composition was applied to the surface opposite to the anti-fusing layer using a gravure coater so that the thickness of the coating film became 1.0 μm, thereby producing a thermal transfer ribbon. Table 1 shows the properties of the film and the thermal transfer ribbon. Composition of coating liquid for thermal transfer ink layer Magenta dye (MSRedG) 3.5% by weight Polyvinyl acetoacetal resin 3.5% by weight Methyl ethyl ketone 46.5% by weight Toluene 46.5% by weight

Example 2 To a mixture of 100 parts by weight of dimethyl 2,6-naphthalenedicarboxylate and 60 parts by weight of ethylene glycol, 0.03 part of manganese acetate tetrahydrate was added, and the mixture was gradually heated from 150 ° C. to 240 ° C. The transesterification reaction was performed while raising the temperature. On the way, when the reaction temperature reached 170 ° C., 0.024 parts of antimony trioxide was added, and 0.3% by weight of spherical silica fine particles were further added.
When the temperature reached 0 ° C., 0.042 parts of tetrabutylphosphonium 3,5-dicarboxybenzenesulfonate (2 m
mol%). Subsequently, a transesterification reaction is performed, and after the transesterification reaction is completed, trimethyl phosphate 0.0
23 parts were added. Thereafter, the reaction product was transferred to a polymerization reactor, the temperature was raised to 290 ° C., and a polycondensation reaction was performed under a high vacuum of 30 Pa or less, and the intrinsic viscosity measured with an o-chlorophenol solution at 25 ° C. was 0.61 dl. / G of polyethylene-2,6-naphthalate. This polymer is filtered through a nonwoven fabric filter having a mesh size of 25 μm, and is drawn in a longitudinal direction (machine axis direction) by a high-speed roll to 150 m by roll stretching.
/ Minute, stretched 4.5 times at 140 ° C., and sequentially biaxially stretched 3.8 times at 145 ° C. in the transverse direction (width direction) to 220, 240, and 240 in the first, second, and third heat fixing and cooling zones, respectively. 18
A film was formed in the same manner as in Example 1 except that the film was heat-fixed and cooled at 0 and 90 ° C. for 2 seconds, and a heat-sensitive transfer ribbon was prepared and evaluated. Table 1 shows the evaluation results.

Comparative Example 1 A film and a heat-sensitive transfer ribbon were prepared and evaluated in the same manner as in Example 1 except that the polymer was filtered with a nonwoven fabric filter having a mesh size of 50 μm. Table 1 shows the evaluation results.

Comparative Example 2 A film and a heat-sensitive transfer ribbon were prepared and evaluated in the same manner as in Example 2 except that the polymer was filtered with a nonwoven fabric filter having a mesh size of 50 μm. Table 1 shows the evaluation results.

Comparative Example 3 A film was formed in the same manner as in Example 1 except that polymer filtration was performed with a nonwoven fabric filter having a mesh size of 100 μm. However, there were many cuts during film formation, and a thermal transfer ribbon could not be produced. Table 1 shows other evaluation results.

Comparative Example 4 A film was formed in the same manner as in Example 2 except that polymer filtration was performed using a sintered metal filter having a mesh size of 100 μm. However, a large number of cuts occurred during the film formation, and a thermal transfer ribbon could not be produced. . Table 1 shows other evaluation results.

Comparative Example 5 The intrinsic viscosity of the polymer was 0.3
A film was formed in the same manner as in Example 1 except that the film thickness was changed to 8 dl / g. However, there were many cuts during the film formation, and a thermal transfer ribbon could not be manufactured. Table 1 shows other evaluation results.

Comparative Example 6 The intrinsic viscosity of the polymer was 0.3
A film was formed in the same manner as in Example 2 except that the film thickness was changed to 9 dl / g. However, there were many cuts during the film formation, and a thermal transfer ribbon could not be manufactured. Table 1 shows other evaluation results.

[0037]

[Table 1]

[0038]

According to the present invention, it is possible to obtain a film which is hardly broken in a film forming process or a film processing process and has excellent productivity. Further, when the film is used for a thermal transfer ribbon, the printing stability is improved. An excellent film can be obtained.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) B29L 7:00 B41M 5/26 B C08L 67:00 101A F term (Reference) 2H111 AA01 AA26 AA27 BB02 BB06 BB08 4F071 AA43 AA44 AA46 AA88 AH16 BB06 BB07 BC01 BC13 BC14 4F210 AA24 AA26 AG01 QA02 QA03 QC05 QC06 QD08 QG01 QG11 QG18

Claims (3)

[Claims] 1. A biaxially oriented film made of polyester, wherein the number of fly specs having an average diameter exceeding 90 μm is 5 / m ² or less, and the intrinsic viscosity is 0.40 dl / g or more. A base film for a thermal transfer ribbon, wherein the base film has a content of 0.90 dl / g or less. 2. Polyester is polyethylene-2,6.
The base film for a thermal transfer ribbon according to claim 1, wherein the base film is naphthalate. 3. The base film for a thermal transfer ribbon according to claim 1, wherein the polyester is polyethylene terephthalate.