JP2002103830A - Thermal transfer film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermal transfer film capable of being freshly printed without void on a printed product for a material to be transferred having low surface smoothness. SOLUTION: The thermal transfer film comprises a heat fusible coloring layer provided on a base film via an intermediate layer not thermally transferred onto the film. In this film, the intermediate layer contains at least a heat fusible substance and a binder resin. The relationship between a peeling force f0 [g/mm] in not heated state between the intermediate layer and a standard tape, a peeling force f80-60 [g/mm] after heated to 80 deg.C and cooled in air to 60 deg.C and a peeling force f80-40 [g/mm] after heated to 80 deg.C and cooled in air to 40 deg.C satisfies 0<=f80-60/f0<=0.7, 0<=f80-40/f0<=0.8 and 5 g/mm<=f0.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal transfer film provided with a coloring layer on a base film via an intermediate layer.
More specifically, the present invention relates to a thermal transfer film capable of performing clear printing without occurrence of white spots on printed matter.

[0002]

2. Description of the Related Art Conventionally, as a thermal transfer recording medium used for a thermal transfer printer, a facsimile, or the like, a thermal transfer film having a coloring layer made of a hot-melt ink on one surface of a base film has been used.

A conventional thermal transfer film uses a base material film such as a capacitor paper or a paraffin paper having a thickness of about 10 to 20 μm, or a plastic film such as a polyester or cellophane having a thickness of about 3 to 20 μm. A coloring layer such as a pigment or a dye is mixed with a binder on a base film, and if necessary, a hot-melt ink containing an additive such as a low-melting agent and a plasticizer is applied to form a coloring layer. It is a thing. Further, there is also a thermal transfer film provided with an intermediate layer adjusted so as to be melted by energy for printing between a base film and a colored layer.

Further, a technique relating to a thermal transfer film in which a coloring layer is provided on a base film via an intermediate layer using a substance having a so-called supercooling property, whose freezing point is lower than the melting point by 10 ° C. or more, has become known. ing. For example, JP-A-61-235189, JP-A-61-286195, JP-A-62-9991, JP-A-62-82084, JP-A-63-302090, JP-A-3-246094 and the like can be mentioned.

[0005] In the thermal transfer film as described above, a predetermined portion is heated and heated by a thermal head from the back side of the base film.
Pressing is performed to melt the colored layer at a portion corresponding to the printing portion of the colored layer, and transfer the image to a transfer target to perform printing.

[0006]

However, using a conventional thermal transfer film in which an intermediate layer and a heat-meltable colored layer are provided on a substrate film, the surface smoothness having a Beck smoothness of 50 seconds or less is used. When printing on a low-transferred object, so-called rough paper, the heat-fusible ink does not transfer well to the transferred object, resulting in the loss of characters and fine lines due to the occurrence of white spots,
There is a problem that the printed matter has a faint appearance.

In a conventional thermal transfer film provided with an intermediate layer using a substance having a supercooling property, when printing is performed on an object to be transferred having a low surface smoothness, characters or fine lines due to white spots are also generated. The problem that the printed matter has a faint appearance due to loss was not solved. An object of the present invention is to improve and solve the above-mentioned drawbacks and problems, and to provide a thermal transfer film capable of performing clear printing without occurrence of white spots on printed matter, for a transfer receiving material having low surface smoothness. I do.

[0008]

In order to achieve such an object, the present inventor has proposed a separation control function of an intermediate layer to which a substance having a supercooling property is added. Only when cooled to a certain temperature range after heating, the peeling force with the colored layer is reduced (to facilitate the transfer of the colored layer), otherwise (unheated portion, when not in use,
At the time of distribution, etc.), various studies were repeated with a focus on the function of maintaining a high peeling force against the colored layer (securing the retention of the colored layer on the base film). Was.

That is, the thermal transfer film of the present invention is a thermal transfer film in which a heat-fusible colored layer is provided on a base film via an intermediate layer which is not heat-transferred, wherein the intermediate layer comprises at least a heat-fusible substance and a binder resin. And a peeling force f ₀ between the intermediate layer and the standard tape when not heated.
[G / mm], peeling force _f80-6 when heated at 80 ° C and left to cool at 60 ° C
₀ [g / mm], peeling force f when heated at 80 ° C and allowed to cool at 40 ° C
_{The relationship of} 0 ≦ f _80-60 / f ₀ ≦ 0.7 0 ≦ f _80-40 / f ₀ ≦ 0.8 5 g / mm ≦ f ₀ is established with _80-40 [g / mm]. Such a configuration was adopted.

In a preferred embodiment of the thermal transfer film of the present invention, the heat-meltable colored layer has a melt viscosity at 100 ° C. {viscosity measured by a cone-plate rotational viscometer (cone low-speed system) specified in JIS Z8803-1991}. 100 ~
The configuration was such that it was within the range of 300 mPa · s.

In the present invention as described above, since the peeling force of the intermediate layer at the portion where the printing energy is applied is set within a predetermined range, the heat-meltable colored layer at the portion where the printing energy is applied is removed. The image is transferred to the transfer-receiving member without any omission.

[0012]

Next, embodiments of the present invention will be described in detail. FIG. 1 is a schematic sectional view showing one embodiment of the thermal transfer film of the present invention. In FIG. 1, a thermal transfer film 1 is provided with a heat-meltable colored layer 4 on a base film 2 via an intermediate layer 3 that is not thermally transferred.

As the substrate film 2 used in the thermal transfer film 1 of the present invention, the same substrate film as used in the conventional thermal transfer film can be used as it is, and other substrates can be used. Done
There is no particular limitation.

[0014] Specific examples of preferred substrate films include:
For example, polyester, polypropylene, cellophane, polycarbonate, cellulose acetate, polyethylene, polyvinyl chloride, polystyrene, nylon, polyimide, polyvinylidene chloride, polyvinyl alcohol, fluororesin, chloride rubber, plastics such as ionomers, condenser paper, paraffin paper, etc. There are papers, non-woven fabric, etc.
Further, a film obtained by combining these may be used. The thickness of the base film 2 can be appropriately set according to the material so that the strength and the thermal conductivity are appropriate, and is, for example, 2.5 to 10 μm.

The intermediate layer 3 constituting the thermal transfer film 1 of the present invention contains at least a heat-fusible substance and a binder resin, and includes an intermediate layer 3 and a standard tape (Sekisui Orient Tape No. 830 manufactured by Sekisui Corporation). (For packing: 50 mm width) and peeling force f ₀ when not heated (g / m)
m], peeling force f _80-60 [g /
mm], peeling force f _80-40 [g when heating at 80 ° C and cooling at 40 ° C
/ Mm] _{between, 0 ≦ f 80-60 / f 0} ≦ 0.7 0 ≦ f 80-40 / f 0 ≦ 0.8 5g / mm ≦ f 0 the relationship is established, preferably 0 ≦ The _relationship f _80-60 / f ₀ ≦ 0.6 0 ≦ f _{80 -40} / f ₀ ≦ _0.76 g / mm ≦ f ₀ holds.

The above f_80-60/ F₀And f_80-40/ F₀Is
The smaller the value, the hot-melt coloring of the printing energy application site
It is preferable because the peeling of the layer 4 becomes light. But f_80-60
/ F ₀Exceeds 0.7, or f_80-40/ F₀But
As it exceeds 0.8 and approaches 1, the intermediate layer 3 and the hot-melt coloring
Adhesion with layer 4 is too strong and heat-fusible
Poor peeling of the color layer occurs, and print white spots are likely to occur.

Also, the peeling force f ₀ [g / mm] when not heated.
Is less than 5 [g / mm], the storage stability is reduced,
A so-called print entanglement occurs in which the heat-fusible colored layer is excessively transferred to a portion where printing is not performed, and a clear image cannot be obtained. The peeling force f ₀ when not heated is preferably as large as possible to obtain the preservability of the thermal transfer film and a clear image, and there is no particular upper limit.

Here, a peeling force f ₀ [g / mm] between the intermediate layer 3 and the standard tape when not heated, a peeling force f _80-60 [g / mm] when heated to 80 ° C. and cooled to 60 ° C., and , 80 ℃ heating 4
A method for measuring the peel force _f80-40 [g / mm] when _{left to} cool at 0 ° C. will be described.

First, a thermal transfer sheet (plain paper UX-P10A4 for facsimile manufactured by Sharp Corporation) is superimposed on the heat fusible transfer layer 4 of the thermal transfer film 1 and a printing evaluation machine (UX-F1CL manufactured by Sharp Corporation) is used. ) To form a solid image in a copy mode (resolution Fine).
FIG. 2 is a perspective view showing the thermal transfer film 1 used for the above printing. As shown in FIG. 2, the heat-fusible transfer layer 4 at the printing portion is removed, and the intermediate layer 3 (the hatched portion in the illustrated example) is exposed. As the thermal transfer paper, the above-mentioned thermal transfer paper having high surface smoothness is used in order to completely remove the heat-fusible transfer layer 4, but it is not particularly limited. It is also possible to remove the heat-fusible transfer layer 4 using an adhesive tape without heating,
If the adhesive strength between the intermediate layer 3 and the heat-fusible transfer layer 4 is high, it is difficult to completely remove the heat-fusible transfer layer 4, which adversely affects the measurement, which is not preferable.

Next, a 100-200 cm long standard tape 11 (Sekisui Corporation Sekisui Orien Tape) is placed on the exposed intermediate layer 3 from which the hot-melt coloring layer 4 has been peeled off.
No. 830 (for packing) 50 mm width). In this bonding, the thermal transfer film 1 is placed on a flat plate, and the standard tape 11 is placed on the intermediate layer 3 with a rubber roller (95 mm in width, 3 mm in diameter).
3 mm, weight 5 kg, rubber hardness 21 degrees (JIS K63
01-1975)). The following measurement is performed within 60 minutes after the pressure bonding in order to avoid the influence of the change in the adhesive force due to the aging after the pressure bonding.

Next, the thermal transfer film was cut out to match the size of the standard tape 11 and the width was 50 mm and the length was 1 mm.
A test piece 21 having a size of 00 to 200 cm is prepared.

Next, the test piece 21 is fixed to a measuring device 31 (Tribogear TYPE14DR, a surface property measuring device manufactured by Shinto Kagaku Co., Ltd.) shown in FIG. Measuring device 31
Has a load converter 32 with a clip 33 mounted thereon, and a slide holder 34 with silicon rubber mounted on the surface. The clip 33 has 60mm x 120m
m, 100 μm thick polyethylene terephthalate (P
ET) Film 37 (Lumilar T-60 manufactured by Toray Industries, Inc.)
Is fixed at one end. The test piece 21 is mounted on the silicone rubber of the slide holder 34 with the standard tape 11 side so that the longitudinal direction thereof is parallel to the slide direction of the slide holder (the direction of arrow A in FIG. 3). Then, the thermal transfer film 1 is peeled off from one end of the test piece 21 (actually, since the hot-melt coloring layer 4 has been removed, the base film 2 and the intermediate layer 3 peel off). Then, the end of the standard tape 11 is attached to the slide holder 3 with the adhesive tape 38.
4 and the peeled end of the thermal transfer film 1 is fixed to the free end of the PET film 37 using a double-sided tape.

As a heating device for heating the test piece 21 on the silicon rubber of the slide holder 34, a silicon rubber heater (50 mm × 200 mm, 0.6 W
/ Cm ² ) and temperature observation means (thermocouple: RKC Corporation AD)
HESIVE TYPE THERMO COUPLECA (K) MODEL: ST-50 _-500 ),
A heating device including a temperature control device (micro-size temperature controller (TF1-10 manufactured by Keyence Corporation)) is prepared. This heating device heats the silicon rubber heater surface while pressing it against the test piece 21 with a load of 1 kg / m ² . In addition, a thermocouple 35 (ADHESIVE TYPE THERMO COUPLE C manufactured by RKC Co., Ltd.) was provided 5 mm in the vicinity of the mounting position of the test piece 21 on the silicon rubber of the slide holder 34.
A (K) MODEL: ST-50 _-50 ) is installed, and the temperature of the test piece 21 can be measured.

[Measurement Method of Peeling Force f ₀ when Not Heated] The test piece 21 is peeled 180 ° under the following measuring conditions in a room temperature environment (25 ± 3 ° C.) to measure the peeling force f ₀ . In the measurement, an average value of the peeling force was calculated from the obtained waveform (recording device (Shinto Scientific Co., Ltd. Analyzing Recorder TYPE)
AR1100) utilizing) the function of, repeatedly this 5 times, the average of the three points excluding the maximum value and the minimum value and the peel force f _0. (Measurement conditions) Measurement environment: 22 to 28 ° C, 20 to 70% RH Load converter: 2000 gf Filter: PASS Range: 100% FS Pulling speed (speed of slide holder 34):
750 mm / min • Movement mode: single mode • Range of recording device: DC 6 V 1.5 Hz • Trigger of recording device: 10% • Trigger buffer memory of recording device: 500

[Peel force f when heated at 80 ° C. and allowed to cool at 60 ° C.]
Measuring method of _80-60 ]
C., and then, when the temperature of the test piece 21 reaches 60 ° C. by cooling, the peeling force f _80-60 is measured under the same measurement conditions as above. The setting of the temperature control device of the heating device is 110 ° C.

[Peeling force f when heated at 80 ° C. and allowed to cool at 40 ° C.]
Measuring method of _80-40 ]
Then, when the temperature of the test piece 21 becomes 40 ° C. by cooling, the peeling force f _80-40 is measured under the same measurement conditions as described above. The setting of the temperature control device of the heating device is 110 ° C.

In the above-mentioned measurement method, the standard tape was Sekisui Orien Tape No. Instead of 830 (for packing) 50 mm width, Nichiban Co., Ltd. cardboard packaging 50 mm width can also be used. In this case, in order to correct the difference in the adhesive strength of the standard tape, the peeling force f ₀ , the peeling force f _80-60 , and the peeling force f ₈₀ obtained by the above-described measurement method using a tape manufactured by Nichiban Co., Ltd. You need to multiply the value of _-40 by 1.2.

The heat-fusible substance contained in the intermediate layer 3 is a super-coolable heat-fusible substance. For example, the heat-fusible substance has a melting peak temperature (a melting peak temperature defined in JIS K7121-1987). It is in the range of 50 to 110 ° C, preferably 60 to 100 ° C, and the crystallization peak temperature of the heat-fusible substance (crystallization peak temperature defined in JIS K7121-1987) is 0 to 100 ° C, preferably 10 to 9 ° C.
It is possible to use a substance which is in the range of 0 ° C. and whose crystallization peak temperature is lower than the melting peak temperature by 10 ° C. or more, preferably 15 ° C. or more.

Here, when there are a plurality of melting peak temperatures, the highest peak temperature is the melting peak temperature, and when there are a plurality of crystallization peak temperatures, the lowest peak temperature is the crystallization peak temperature.

If the melting peak temperature of the heat-fusible substance is less than 50 ° C., the high-temperature preservability of the thermal transfer film is lowered, which is not preferable. If it exceeds 110 ° C., the peel strength of the intermediate layer is lowered, which is excessively large. The applied energy is required, and the effect of adding the heat-fusible substance cannot be substantially obtained, which is not preferable. Furthermore, if the crystallization peak temperature of the heat-fusible substance is less than 0 ° C., after the application and drying of the intermediate layer, the state in which the heat-fusible substance is melted continues excessively. There is a problem that the base film surface and the intermediate layer adhere to each other. In addition, when the crystallization peak temperature exceeds 100 ° C., when peeling after printing, under a normal printing environment, the heat-fusible substance of the low-viscosity intermediate layer that is melted after printing heating is crystallized and solidified. However, white spots occur on the printed matter and clear printing cannot be performed, which is not preferable. Further, if the temperature difference at which the crystallization peak temperature is lower than the above-mentioned melting peak temperature is less than 10 ° C., a sufficient supercooling effect cannot be obtained unless an energy that greatly exceeds the melting peak is applied, and substantially heat The effect of adding the fusible substance is not obtained, which is not preferable.

Examples of the heat-fusible substance having a supercooling property as described above include polyester resins. For example, lactone resins such as polycaprolactone, or succinic acid, adipic acid, azelaic acid, Aliphatic dibasic acids such as sebacic acid, dodecane diacid, dimer acid and aromatic dibasic acids such as terephthalic acid, isophthalic acid, orthophthalic acid, naphthalenedicarboxylic acid, 5-sodium sulfoisophthalic acid, tetrahydrophthalic anhydride, hexahydro An aliphatic dibasic acid such as phthalic anhydride and hexahydroterephthalic acid, wherein the glycol component is ethylene glycol, 1,4-butanediol, 1,5-pentadiol, 1,6-hexanediol, 1,8-octane Diol, 1,9-nonanediol, 1,10-octanediol, propylene Glycol, neopentyl glycol, cyclohexane dimethanol, tricyclodecane dimethanol, ethylene oxide and / or propylene oxide adduct of bisphenol A, polyethylene glycol, polytetramethylene glycol, polypropylene glycol-3,3-dimethylol heptane, etc. A polyester resin is exemplified.

The binder resin contained in the intermediate layer 3 may be, for example, a resin having a softening temperature (JISK2207-1980).
Softening temperature measured by the ring and ball method specified in 130)
Those having a temperature in the range of 0 ° C, preferably 140 to 300 ° C can be used. Examples of such binder resins include polyester resins, polybutadiene resins such as SBR resins, ABS resins and SBS resins, maleic resins such as styrene-maleic anhydride copolymers, olefin resins, olefin copolymers, An ionomer resin, a styrene resin, and the like can be given.

The softening temperature of the binder resin (JIS K2
When the softening temperature measured by the ring and ball method defined in 207-1980) is lower than 130 ° C., in the process of drying after applying the coating liquid for providing the intermediate layer on the base film,
It becomes difficult to properly separate the binder resin and the heat-fusible substance, and the effect exhibited by the super-cooled state of the heat-fusible substance is not substantially obtained, and the colored layer is removed from the transfer paper. In some cases, it is difficult to perform the transfer without the use.

The softening temperature (JIS K2207-1)
Softening temperature measured by ring and ball method specified in 980) is 400
Since the binder resin exceeding ℃ is often an expensive material due to having excessive heat resistance,
This causes a problem that the production cost of the thermal transfer film becomes excessive.

In the thermal transfer film 1 of the present invention, the intermediate layer 3 may contain carbon black. Thereby, the printed content is read from the thermal transfer film after printing (the thermally fusible colored layer 4 of the thermal transfer film 1 after the transfer).
It is difficult to read the content printed on the transfer film from the copy obtained by copying the shells of the
It is also possible to provide a security leak prevention function. In addition, since the carbon black prevents the heat transfer film from being charged, the workability at the time of replacing the heat transfer film is improved, and dust in the air is prevented from being attracted by dust in the air at the time of printing, thereby preventing the printed matter from falling off. A printed matter can be obtained.

The intermediate layer 3 is formed by dispersing the above-mentioned materials and a higher aliphatic alcohol, a phosphoric acid ester and its metal salt, an organic carboxylic acid and its derivative, a low-melting wax, various surfactants and the like. The coating agent is added as needed, and dissolved or dispersed in an appropriate solvent such as methyl ethyl ketone, toluene, alcohols, water, etc. to prepare a coating solution, and a conventional coating solution such as a gravure coater, a roll coater, and a wire bar is used. Coating and drying may be performed by a construction means.

The coating amount of the intermediate layer 3 is 0.
About 1 to 1.0 g / m ² is preferable. 0.1 g coating amount
/ M ² , it is difficult to obtain clear printed matters without white spots. On the other hand, when the coating amount exceeds 1.0 g / m ² , the intermediate layer is too thick, It is not preferable because the printing sensitivity is lowered.

In the present invention, "intermediate without thermal transfer"
"Layer" means that the thermal transfer film is heated by the thermal head
When transferred, the intermediate layer is substantially transferred from the base film
Means not. Specifically,
A and B values obtained by the following procedure are B / A> 0.85
The one that satisfies the relationship is defined as "no thermal transfer"
And : Thermal transfer paper on the heat-meltable transfer layer of thermal transfer film
(Plain paper UX-P10 for facsimile manufactured by Sharp Corporation)
A4) and print evaluation machine (U
X-F1CL) and a copy mode (resolution Fi)
In ne), a solid image is formed. Thermal transfer paper is heat-melted
Surface smoothness to complete removal of the transfer layer
Use the above thermal transfer paper with high
Not something. Exposure on this used thermal transfer film
Coating amount [g / m ^Two] And measure A
I do. : Exposure of used thermal transfer film
In the intermediate layer portion that was
Is performed. Thus, the thermal transfer heater heated twice in total
Coating of the exposed intermediate layer part on the film
Amount [g / m^Two] To B.

The heat-meltable coloring layer 4 constituting the thermal transfer film 1 of the present invention comprises a conventionally known coloring agent and a binder. If necessary, a mineral oil, a vegetable oil, a higher fatty acid such as stearic acid, a plasticizer, It can be formed by adding various additives such as an antioxidant and a filler.

Examples of the wax component used as the binder include microcrystalline wax, carnauba wax, and paraffin wax. Furthermore,
Various waxes such as Fischer-Tropsch wax, various low molecular weight polyethylene, wood wax, beeswax, spermaceti, Ibota wax, wool wax, shellac wax, candelilla wax, petrolactam, polyester wax, partially modified wax, fatty acid ester, fatty acid amide, etc. Is used. Among them, those having a melting point of 50 to 85 ° C are particularly preferable. If the temperature is lower than 50 ° C., a problem occurs in storage stability, and if the temperature exceeds 85 ° C., the sensitivity becomes insufficient.

As the resin component used as the binder, for example, ethylene-vinyl acetate copolymer, ethylene-acrylate copolymer, polyethylene, polystyrene, polypropylene, polybutene, petroleum resin, vinyl chloride resin, vinyl chloride-acetic acid Vinyl copolymer, polyvinyl alcohol, vinylidene chloride resin, methacrylic resin, polyamide, polycarbonate, fluororesin, polyvinyl formal, polyvinyl butyral, acetyl cellulose, nitrocellulose, polyvinyl acetate, polyisobutylene, ethyl cellulose or polyacetal, and the like. Particularly, those having a relatively low softening point conventionally used as a heat-sensitive adhesive, for example, a softening point of 50 to 80 ° C are preferable.

The colorant can be appropriately selected from known organic or inorganic pigments or dyes.
For example, it has a sufficient coloring density, discolors due to light, heat, etc.
Those that do not fade are preferred. Further, it may be a substance that develops color by heating or a substance that develops color when it comes into contact with a component applied to the surface of the transfer-receiving body. Further, the color of the colorant is not limited to cyan, magenta, yellow, and black, and various colors of colorants can be used.

Further, in order to provide the heat-meltable colored layer 4 with good heat conductivity and heat-melt transferability, a heat-conductive substance may be blended as a filler for the binder. Examples of such a filler include carbonaceous substances such as carbon black, and metals and metal compounds such as aluminum, copper, tin oxide, and molybdenum disulfide.

The heat-meltable colored layer 4 is formed by the above-described colorant component and binder component, and if necessary, mineral oil, vegetable oil, higher fatty acids such as stearic acid, plasticizer, oxidizer, etc. Various additives such as an inhibitor and a filler are added, and water, a coating solution for forming a colored layer prepared by blending a solvent component such as an organic solvent, is coated with a conventionally known hot melt coat, hot lacquer coat, or gravure coat. , Gravure reverse coating, roll coating and the like. Also, there is a method of forming using an aqueous or non-aqueous emulsion coating liquid.

The thickness of the heat-meltable colored layer 4 should be determined so as to balance the required printing density with the thermal sensitivity, and is preferably in the range of 0.5 to 6.5 g / m ² . ,
A range of 2.5 to 5.0 g / m ² is particularly preferred.

The hot-melt colored layer 4 as described above is composed of 1
Melt viscosity at 00 ° C ｛JISZ8803-1991
Is 100 to 300 mPa · s, preferably 15 by a cone-plate type rotary viscometer (cone low speed method) specified in
It is desirable to be within the range of 0 to 250 mPa · s.
The melt viscosity at 100 ° C. of the hot-melt colored layer is 100 m
When the viscosity is less than Pa · s, no further effect of preventing slippage on rough paper is obtained, and when the melt viscosity exceeds 300 mPa · s, the coating aptitude at the time of applying and forming the hot-melt coloring layer by the hot melt coating method. And coating in a favorable surface condition may be difficult.

The melt viscosity of the hot-melt colored layer at 100 ° C. can be measured as follows. That is, an appropriate amount of the thermal transfer film is cut out, placed on a hot plate having a surface temperature of 100 ° C. so that the hot-melt coloring layer is on the top, and the melted hot-melt coloring layer is scraped with a spatula or the like and collected. Sample for Using this sample, the melt viscosity at 100 ° C. is measured by the following measuring device. -Device name: Viscoelasticity measuring device Rotovisco RV20 (HA
・ Measurement head: M5 ・ Sensor system: Sensor system cone plate PK5 (opening angle 0.5 °, cone plate radius 25m)
m) or sensor system MV type (MV1). However, an appropriate cone plate and sensor system must be appropriately selected according to the viscosity region to be measured.

The thermal transfer film of the present invention prevents the thermal head from sticking to the other surface of the base film, and
In order to improve the slipperiness, a heat-resistant slippery layer can be provided. The heat-resistant lubricating layer is formed by suitably using a binder resin to which a slip agent, a surfactant, inorganic particles, organic particles, a pigment and the like are added.

The binder resin used in the heat-resistant lubricating layer includes, for example, cellulose resins such as ethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, methyl cellulose, cellulose acetate, cellulose acetate butyrate, and nitrified cotton, polyvinyl alcohol, polyvinyl acetate, and the like. Polyvinyl butyral, polyvinyl acetal,
Examples include vinyl resins such as polyvinylpyrrolidone, acrylic resin, polyacrylamide, acrylonitrile-styrene copolymer, polyester resin, polyurethane resin, silicone-modified or fluorine-modified urethane resin. Among them, it is preferable to use a cross-linking resin using one having several reactive groups, for example, a hydroxyl group, and using a polyisocyanate or the like as a cross-linking agent.

Means for forming the heat-resistant lubricating layer is to dissolve or disperse a material obtained by adding a slipping agent, a surfactant, inorganic particles, organic particles, pigments, etc. to the binder resin as described above in an appropriate solvent. A coating solution is prepared, and the coating solution is applied by a conventional coating means such as a gravure coater, a roll coater, and a wire bar, and dried.

Incidentally, the thermal transfer film of the present invention is not limited to the above embodiment of the present invention. Needless to say, the thermal transfer film of the present invention can be applied to color printing, and a multicolor thermal transfer film is also included in the scope of the present invention. Further, the transfer object used in combination with the thermal transfer film of the present invention can be any conventionally known transfer object.

[0052]

Next, the present invention will be described more specifically with reference to examples. In the following description, “parts” or “%” is based on weight unless otherwise specified.

A 4.5 μm thick polyethylene terephthalate film (manufactured by Toray Industries, Inc.) was used as a base film for Samples 1 to 20, and an intermediate layer having the composition shown in Table 1 below was coated on the base film. Coating the working liquid by gravure coating method (coating amount 0.5 g / m
² ) Then, the solvent was dried with hot air at 100 ° C., and the film was wound up. The solvent used was toluene.

[0054]

[Table 1] The types of the heat-fusible substance, the binder resin, and the carbon black used for the intermediate layer are as follows. (1) Praxel 220 (polycaprolactone diol, manufactured by Daicel Chemical Industries, Ltd., melting peak temperature: 55)
° C, crystallization peak temperature: 28 ° C) (2) Supercoolable polyester A (melting peak temperature: 70)
° C, crystallization peak temperature: 29 ° C) (3) Supercooling polyester B (melting peak temperature: 68)
° C, crystallization peak temperature: 46 ° C) (4) Supercoolable polyester C (melting peak temperature: 64)
° C, crystallization peak temperature: 16 ° C) (5) Supercoolable polyester D (melting peak temperature: 74)
° C, crystallization peak temperature: 45 ° C) (6) Byron 200 (manufactured by Toyobo Co., Ltd.) carbon black: average particle size 40 nm (manufactured by Mitsubishi Chemical Corporation)

Next, a hot-melt colored layer coating solution having the following composition was heated to 100 ° C. on each intermediate layer, and dried to a thickness of 4.0 μm by hot melt coating using a roll coat method. To form a heat-meltable colored layer, thereby producing thermal transfer films (Samples 1 to 20). However, on the other surface of the base film, a heat-resistant lubricating layer coating solution having the following composition was applied by a roll coater, dried and dried.
A heat-resistant lubricating layer having a thickness of μm is provided in advance.

(Hot-melting colored layer coating solution) 15 parts of carbon black (average particle size 40 nm, manufactured by Mitsubishi Chemical Corporation) 9 parts of ethylene-vinyl acetate copolymer (Smitate HC10, Sumitomo Chemical Co., Ltd.)・ Carnauba Wax (Kato Yoko Co., Ltd.) 38 parts ・ Paraffin wax (Nippon Seiro Co., Ltd. SP-0145) 38 parts

(Heat-resistant lubricating layer coating liquid)-Polyvinyl butyral resin 20 parts (S-LEC BX-1 manufactured by Sekisui Chemical Co., Ltd.)-Talc (Microace L-1 manufactured by Nippon ALC Co., Ltd.) 30 parts-Melamine resin Fine particles 30 parts (Nippon Shokubai Chemical Co., Ltd. Eposter S) ・ Polyisocyanate 40 parts (Takeda Pharmaceutical Co., Ltd. Takenate A-3) ・ Toluene / methyl ethyl ketone (weight ratio 1/1) 900 parts

Preparation of Comparative Samples 1 to 6 Thermal transfer films (Comparative Samples 1 to 6) were prepared in the same manner as Samples 1 to 20 except that the coating solution for the intermediate layer was changed to the composition shown in Table 1 above. .

Evaluation The thermal transfer film obtained as described above (samples 1 to 2)
0, and Comparative Samples 1 to 6) as Sekisui Corporation's Sekisui Orien Tape No. 830
(For packing) The peeling force f ₀ between the intermediate layer and the standard tape when not heated according to the above-described measuring method using a width of 50 mm.
[G / mm], peeling force f when heated at 80 ° C and cooled down at 60 ° C
_80-60 [g / mm], and was measured 80 ° C. heating 40 ° C. cooling time of peel force _{f 80- 40 [g / mm]} . And f
The value of _80-60 / _{f 0,} the value of _{f 80-40} / f _0, and exhibited a peel force _{f 0} in Table 2 below. The thermal transfer films (Samples 1 to 20 and Comparative Samples 1 to 6) were evaluated for print quality (occurrence of entanglement), print quality (occurrence of white spots), and confidential leakage prevention by the following evaluation methods. . The evaluation results are shown in Table 2 below.

<Print Quality (Generation of Entanglement)> Facsimile (Telecopier 703) manufactured by Fuji Xerox Co., Ltd.
3) Using Xerox Corporation printer paper (#
(4024, Beck smoothness: 32 seconds) and printing was performed in the copy mode using the above-mentioned thermal transfer film. In order to be able to change the printing energy of the thermal head to an arbitrary value, a facsimile that was appropriately modified so that an arbitrary voltage could be externally applied between the common electrode and the ground electrode of the thermal head mounted on the facsimile was used. . The manuscript to be copied includes an Oki Electric printer (MICROLINE 900PSII L).
T) Fuji Xerox Co., Ltd. copy paper (WR-1
00), a 6-point size uppercase and lowercase alphabet (courier typeface) printed material was used.

When printing, a thermal transfer film (sample 3
When the above-mentioned original is copied in -1 to 3-5), printing is performed with the minimum voltage that allows the distinction between capital letters E and B. Then, the printing result of the lowercase alphabet at the time of printing at the lowest voltage was visually observed, and the occurrence of character crushing due to the entanglement phenomenon was evaluated according to the following criteria.

The "entanglement phenomenon" in the present invention refers to a transfer state in which the colored layer of the thermal transfer film adheres in a thin film form without fusing to the surface of the transfer object. In addition, in the present invention, “crush” indicates a state in which a plurality of lines constituting a character are connected by the transferred colored layer. A: Almost no crushing of characters due to the occurrence of entanglement was observed, and a good printed matter was obtained. Δ: Slight crushing of characters due to the occurrence of entanglement was observed, but a printed matter in which characters could be discriminated well was obtained. C: Character crushing due to the occurrence of entanglement was considerably observed, and a printed matter in which it was difficult or impossible to determine the character was obtained.

<Print Quality (Occurrence of White Area)> Facsimile (Telecopier 70, manufactured by Fuji Xerox Co., Ltd.)
33) using Xerox Corporation printer paper (#
The printing was performed in the copy mode (document type: character, print density: normal) using the above thermal transfer films at 4024, Beck smoothness of 32 seconds. After printing, the thermal transfer film was separated from the printer paper by a cold release process performed after the temperature of the thermal transfer film was cooled to room temperature.

In order to change the printing energy of the thermal head to an arbitrary value, an arbitrary voltage can be externally applied between the common electrode and the ground electrode of the thermal head mounted on the facsimile. The manuscript to be copied includes a printer (M
8-point size uppercase alphabet (typeface is C) printed on copy paper (WR-100) manufactured by Fuji Xerox Co., Ltd. with ICROLINE 900 PSII LT
(ourier) printed matter was used.

At the time of printing, when the above-mentioned original was copied on each of the thermal transfer films (samples 1 to 20 and comparative samples 1 to 6), capital letters E and B could be visually distinguished with the minimum applied voltage that was possible. We decided to print. Then, the obtained printed matter was visually observed, and the loss of characters and fine lines due to the occurrence of white spots was evaluated according to the following criteria. ：: Defects of characters and fine lines due to the occurrence of white spots were hardly observed, and extremely good printed matter was obtained. ：: Defects in characters and fine lines due to occurrence of white spots were slightly observed, but good printed matter was obtained. X: The loss of characters and fine lines due to the occurrence of white spots was remarkably observed, and a printed matter having an appearance in which the characters and fine lines were remarkably blurred was obtained.

<Prevention of Security Leakage> The colored layer surface of the thermal transfer film after printing under the same printing conditions as in the above-described print quality evaluation was measured with a Fuji Xerox Co., Ltd. copier (Vision 675) by Fuji Xerox Co., Ltd. Copied on company-made copy paper (WR-100). The density setting for copying was "automatic". The image copied on the copy paper was visually observed, and whether or not the content printed on the thermal transfer film could be read was evaluated according to the following criteria. ：: The printed content could not be read. ：: The printed contents could hardly be understood. ×: The printed contents could be easily read.

[0067]

[Table 2]

As shown in Table 2, it was confirmed that the heat transfer film (samples 1 to 20) of the present invention had foil holding properties and printing quality at practical levels. Further, a thermal transfer film containing carbon black in the intermediate layer (samples 1 to 1)
No. 0) was confirmed to be excellent in preventing leakage of confidential information. On the other hand, comparative thermal transfer films (Comparative Samples 1 to 6)
In either case, any of foil loss and white spots was observed, and it was not practical.

[0069]

As described in detail above, according to the present invention,
Since the peeling force of the intermediate layer at the portion where the printing energy is applied is set within a predetermined range, the heat-meltable coloring layer at the portion where the printing energy is applied is transferred to the transfer-receiving member without causing a detachment. As a result, it is possible to obtain a thermal transfer film capable of performing favorable printing with less occurrence of white spots.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing one embodiment of a thermal transfer film of the present invention.

FIG. 2 shows a peeling force f ₀ between the intermediate layer and the standard tape when not heated, a peeling force f _80-60 when heating at 80 ° C. and cooling down at 60 ° C., and a peeling force f when heating at 80 ° C. and cooling down at 40 ° C. It is a perspective view for _{demonstrating} the measuring method of _80-40 .

FIG. 3 shows a peeling force f ₀ between the intermediate layer and the standard tape when not heated, a peeling force f _80-60 ° C. when heated to 60 ° C., and a peeling force f when 80 ° C. and cooled to 40 ° C. It is a schematic perspective view for explaining the measuring device used for measurement of _80-40 .

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Thermal transfer film 2 ... Base film 3 ... Intermediate layer 4 ... Hot-melt coloring layer 11 ... Standard tape 31 ... 180 degree peeling force measuring device 32 ... Load converter 33 ... Clip 34 ... Slide holder 35 ... Thermocouple 37 ... PET film 38 ... Adhesive film

Continuation of the front page (72) Inventor Mitsuru Maeda 1-1-1, Ichigaga-cho, Shinjuku-ku, Tokyo Inside Dai Nippon Printing Co., Ltd. (72) Inventor Masanori Torii 1-1-1, Ichigaga-cho, Shinjuku-ku, Tokyo F-term (reference) in Dai Nippon Printing Co., Ltd. 2H111 AA14 BA03 BA04 BA07 BA12 BA53 BA63 BA70

Claims (2)

[Claims] 1. An intermediate layer which is not thermally transferred on a base film.
A thermal transfer film provided with a heat-meltable colored layer
The intermediate layer may include at least a heat-fusible substance and a binder.
Resin, and the intermediate layer and the standard tape
Peel force f when hot ₀[G / mm], 80 ° C heating, 60 ° C cooling
Peeling force f_80-60[G / mm], 80 ° C heating, 40 ° C release
Peeling force f when cold_80-40[G / mm], 0 ≦ f_80-60/ F₀≦ 0.7 0 ≦ f_80-40/ F₀≦ 0.8 5g / mm ≦ f₀ A thermal transfer film characterized by the following relationship. 2. The heat-meltable colored layer has a melt viscosity at 100 ° C., which is determined by a cone defined in JISZ8803-1991.
Viscosity に よ る by a flat plate rotational viscometer (cone low speed method) is 10
The thermal transfer film according to claim 1, wherein the thermal transfer film is within a range of 0 to 300 mPa · s.