JP2002103829A - Thermal transfer film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermal transfer film capable of freshly printing without void on a printed product by a releasing process in cooling of a material to be transferred having a 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, a cold 180 deg.-peeling force F1 between the intermediate layer and the coloring layer is in a range of 1.5 to 20.0 g/50 mm. A hot 180 deg.-peeling force F2 between the intermediate layer and the coloring layer is in a range of 0 to 5.0 g/50 mm, and the relationship between the force F1 and the force F2 satisfies 0.1 g/50 mm<=(F1-F2)<=20.0 g/50 mm.

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 having a heat-meltable colored layer provided on a base film via an intermediate layer, and more particularly, to the occurrence of white spots on printed matter due to a cold peeling process. The present invention relates to a one-time thermal transfer film capable of producing clear prints (not assumed to be printed many times).

[0002]

2. Description of the Related Art Conventionally, as a thermal transfer recording medium used in a thermal transfer printer, a facsimile, and the like, a thermal transfer film having a heat-fusible colored 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 colorant such as a pigment or a dye is mixed with a binder on a base film, and if necessary, a hot-melt ink containing a low-melting agent and an additive such as a plasticizer is applied to apply a hot-melt color. It is provided with a layer. There is also a thermal transfer film provided with an intermediate layer adjusted between the base film and the heat-meltable colored layer so as to be melted by the energy for printing.

[0004] A predetermined position is heated and pressurized by a thermal head from the back side of the base film to melt the hot-melt coloring layer of the hot-melt coloring layer at a portion corresponding to the printing portion, and the heat-meltable coloring layer is applied to the transfer target. This is to transfer and print.

[0005]

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 order to solve such a problem, a method of using a heat transfer film having a thicker heat-meltable colored layer has been adopted. However, when the thickness of the heat-meltable colored layer is increased, the cohesive force of the heat-meltable colored layer is reduced, and the ink easily falls off and blocking is likely to occur.

[0007] It has also been practiced to form a thin heat-meltable colored layer using a hot-melt ink containing various resins to prevent the ink from falling off. However, in this case, the energy required for printing is increased, or a thermal peeling process (peeling the transferred body and the thermal transfer film when the intermediate layer of the thermal transfer film is in a molten and highly fluid liquid state) is performed. Requires a special printing method.

By the way, substances having a so-called supercooling property in which the freezing point is lower than the melting point by 10 ° C. or more are known from various documents. A technique relating to a thermal transfer film in which a heat-meltable coloring layer is provided on a base film via an intermediate layer using various substances having supercooling properties is known. For example, JP-A-61-235189,
JP-A-61-286195, JP-A-62-9991, JP-A-62-82084, JP-A-63-302090, and JP-A-3-246094. On the other hand, it is known from various documents that a polycaprolactone resin has supercooling properties. A technique relating to a thermal transfer film in which a heat-meltable colored layer containing the polycaprolactone-based resin is provided on a base film is known. For example, JP-A-59-230795, JP-A-60-1221
94, JP-A-60-122195, JP-A-61-185
492, JP-A-62-259089, JP-A-5-3207
3 and the like.

Further, a technique relating to a thermal transfer film in which a heat-fusible colored layer is provided on a base film via an intermediate layer using the polycaprolactone resin is known. For example, JP-A-60-165291 discloses that a polycaprolactone-based resin is used for an intermediate layer for the purpose of printing many times, and JP-A-7-232483 discloses that a high-speed printing and smooth operation in a high-temperature atmosphere are performed. For the purpose of enabling printing,
It is disclosed that a polycaprolactone having a molecular weight of 10,000 or less is used for a primer layer.

However, in the case of a thermal transfer film using an intermediate layer according to these techniques, when printing is performed on an object to be transferred having a low surface smoothness, characters and fine lines are also lost due to the occurrence of white spots, resulting in a printed matter. The problem of a faint appearance was not eliminated. Further, there is a problem that it is difficult to perform good printing and image formation by the cold peeling process.

The present invention solves and solves the above-mentioned drawbacks and problems, and a thermal transfer film capable of clear printing without causing white spots on a printed material by a cold peeling process on an object having low surface smoothness. The purpose is to provide.

[0012]

In order to achieve such an object, the present inventors have made various studies focusing on the peeling force between the intermediate layer and the heat-meltable colored layer of the thermal transfer film after printing. As a result of the superposition, the present invention related to the thermal transfer film was achieved.

That is, the heat transfer film of the present invention is a heat transfer film having a heat fusible colored layer provided on a substrate film via an intermediate layer which is not thermally transferred. Peeling force at cold F1 is 1.5
２20.0 g / 50 mm, and the 180 ° hot peel force F2 between the intermediate layer and the hot-melt colored layer is 0 to 20.0 g / 50 mm.
5.0 g / 50 mm;
0.1 g / 50 mm ≦ (F1−F2) ≦ 20.0 g / ° between the cold peeling force F1 and the 180 ° hot peeling force F2.
The configuration was such that a relationship of 50 mm was established.

In a preferred embodiment of the thermal transfer film of the present invention, a value of 0.5 g / 50 mm ≦ (F1-F) is satisfied between the 180 ° cold peeling force F1 and the 180 ° hot peeling force F2.
2) The configuration was such that the relationship of ≦ 5.0 g / 50 mm was established.

In a preferred embodiment of the thermal transfer film of the present invention, the intermediate layer contains at least a heat-fusible substance and a binder resin, and the melting peak temperature (J
The melt viscosity of the heat-fusible substance in a temperature range 15 to 25 ° C. higher than the melting peak temperature specified in ISK7121-1987 {viscosity measured by a cone-plate rotary viscometer (cone low-speed method) specified in JIS Z8803-1991}. Within the range of 100 to 1000 mPa · s, and the melting peak temperature (JIS K7121-19) of the heat-fusible substance.
87 is within the range of 50 to 110 ° C., and the crystallization peak temperature (JI
Crystallization peak temperature defined in SK7121-1987)
Is in the range of 0 to 100 ° C., the crystallization peak temperature is at least 10 ° C. lower than the melting peak temperature, and the softening temperature of the binder resin (JIS K22)
Softening temperature measured by the ring and ball method specified in 07-1980)
Is in the range of 130 to 400 ° C.

In a preferred embodiment of the thermal transfer film of the present invention, the melt viscosity of the hot-melt colored layer at 100 ° C. {viscosity measured by a cone-plate rotary 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.

Further, in a preferred embodiment of the thermal transfer film of the present invention, the melting peak temperature (JI
Melting peak temperature specified in SK7121-1987)
And a difference between the melting peak temperature of the heat-fusible substance contained in the intermediate layer (the melting peak temperature defined in JIS K7121-1987) is 10 ° C. or less.

In the present invention as described above, even when the intermediate layer and the hot-melt colored layer are separated from the intermediate layer and the hot-melt colored layer at a portion where the printing energy is applied, the separation force is within a predetermined range even when the intermediate layer is cooled to about room temperature between printing and peeling. Since the heat-meltable colored layer at the portion where the printing energy is applied is transferred to the transfer-receiving member without causing a dropout.

[0019]

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. And
180 ° cold peel force F between the intermediate layer 3 and the hot-melt colored layer 4
1 is 1.5 to 20.0 g / 50 mm, preferably 2.5
１12.0 g / 50 mm, and the 180 ° hot peel force F2 between the intermediate layer 3 and the hot-melt colored layer 4 is 0-5.
0 g / 50 mm, preferably in the range of 0 to 2.5 g / 50 mm. Furthermore, the 180 ° cold peeling forces F1 and 18
0.1 g / 50 mm ≦ (F
1-F2) ≦ 20.0 g / 50 mm, preferably 0.5
g / 50 mm ≦ (F1-F2) ≦ 5.0 g / 50 mm.

180 ° between the intermediate layer 3 and the hot-melt colored layer 4
When the cold peeling force F1 is less than 1.5 g / 50 mm, a so-called print entanglement in which the heat-fusible colored layer is excessively transferred to a portion where printing is not performed occurs, and a clear image can be obtained. Can not. On the other hand, the 180 ° cold peeling force F1 is 2
When the composition exceeds 0.0 g / 50 mm, the coating liquid for forming the hot-melt coloring layer 4 has a high melt viscosity containing a large amount of resin components, and the hot-melt coloring layer 4 is coated with hot melt. The coating aptitude at the time of applying and forming by the method is lowered, and it is difficult to apply in a good surface state.

The intermediate layer 3 and the hot-melt colored layer 4
When the 80 ° hot peel force F2 exceeds 5.0 g / 50 mm, white spots occur and a clear image cannot be obtained. The smaller the value of the 180 ° hot peel force F2, the better, and 0 g / 50 mm is the most preferable.

If (F1−F2) is less than 0 g / 50 mm, entanglement of printing or white spots may occur.
A clear image cannot be obtained. On the other hand, (F1-F
When 2) is configured to exceed 20.0 g / 50 mm, the coating liquid for forming the heat-meltable colored layer 4 becomes a resin having a high melt viscosity with a large amount of resin components. The coating aptitude at the time of applying and forming by the hot melt coating method is reduced, and it becomes difficult to apply the composition in a good surface condition.

In the present invention, the "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.

Here, the 180 ° cold peeling force F1 between the intermediate layer and the hot-melt colored layer in the present invention, and 180 °
A method for measuring the hot peel force F2 will be described. First, as shown in FIG. 2, an object to be transferred 11 (UX-P10A4 manufactured by Sharp Corporation) having a Beck surface smoothness of 140 to 200 seconds is overlaid on the heat-meltable transfer layer 4 of the heat transfer film 1. Alignment and print evaluation machine (UX-F1 manufactured by Sharp Corporation)
CL), a solid image is formed by heating the thermal head, and the thermal transfer film 1 and the transfer-receiving body 11 are left for 1 day in an environment of 30 ° C. while being adhered to each other. Next, a width of 50 mm and a length of 100 to 100 mm are set within the solid image forming region of the bonded body of the thermal transfer film 1 and the transfer body 11.
A test piece 21 having a size of 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 to which a clip 33 is attached, and a slide holder 34. In clip 33,
One end of a 60 mm × 120 mm, 100 μm thick polyethylene terephthalate (PET) film 37 (Lumilar T-60 manufactured by Toray Industries, Inc.) is fixed. Test piece 2
Reference numeral 1 denotes an object to be transferred so that its longitudinal direction is parallel to the sliding direction of the slide holder (the direction of arrow A in FIG. 3).
One side is fixed to the slide holder 34 with a double-sided tape. Then, as shown in the figure, the thermal transfer film 1 is peeled off from one end of the test piece 21 (actually, since the heat-meltable colored layer 4 has been transferred to the transferred body 11, the base film 2 and the intermediate layer 3 are peeled off). Then, 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. 18 of the intermediate layer and the hot-melt colored layer
0 ° cold peel force F1 and 180 ° hot peel force F2
In the measurement of, both values are measured in one test piece 21 in order to minimize a measurement error between samples.

Measurement Method of 180 ° Cold Peeling Force F1 Next, a ribbon heater heated to about 45 ° C.
The test piece 21 was placed on the test piece 21 through the PET film 37 of μm, and was heated to 40 ° C.
When the temperature of 1 became 35 ° C., 1
Measure the 80 ° peel force. The measurement distance is about 20mm,
Slide holder 34 is about 40 mm in the direction of arrow A in FIG.
Move and stop. In the measurement, the average value of the peeling force was calculated from the obtained waveform (using the function of a recording device (analyzing recorder TYPE AR1100 manufactured by Shinto Kagaku Co., Ltd.)), and the tensile resistance of only the peeled film was calculated from the value. The value obtained by subtracting the force is measured 5 times. The average of the three points excluding the maximum and minimum values is the 180 ° cold peel force F
Let it be 1. In addition, the temperature of the test piece 21 is measured with a K thermocouple (ST-50-500, a portable temperature sensor manufactured by Rika Kogyo Co., Ltd.).

(Measurement conditions) Measurement environment temperature: 20 to 25 ° C. Load converter: 100 gf (980 mN) Filter: PASS Range: 10% FS, 25% 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: 4% • Trigger buffer memory of recording device: 8000 • Chart speed of recording device: 1.0 ms

Measuring Method of 180 ° Hot Peeling Force F2 Further, using a test piece 21 for which the 180 ° cold peeling force F1 was measured, approximately 130
100μm PET ribbon heater heated to 100 ℃
After the test piece 21 was heated to 80 ° C. after being placed via the film 37 and the temperature of the test piece 21 reached 35 ° C., the slide holder 34 was measured under the same measurement conditions as described above.
Is moved further 40 mm from the position where it was stopped at the time of measuring the 180 ° cold peel force F1, and the 180 ° peel force is measured. The value obtained by the same method as described above is defined as the 180 ° hot peel force F2. In addition, the same value as the value used in the above-described measurement of the 180 ° cold peeling force F1 is used as the tensile resistance of only the peeled film.

In the present invention, the peeling force between the intermediate layer and the hot-melt colored layer at the portion where the printing energy is applied is determined as the 180 ° cold peeling force F1 and the 180 ° hot peeling force F2 as described above. Therefore, even when cooled to about room temperature between printing and peeling, the heat-meltable colored layer at the portion where the printing energy is applied is transferred to the transfer-receiving member without causing any omission. You.

Next, components of the thermal transfer film of the present invention will be described. (Substrate film) As the substrate film used in the thermal transfer film of the present invention, the same substrate film as that 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.

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 substrate film in which these are combined may be used.

The thickness of the substrate film can be appropriately changed depending on the material so that the strength and the thermal conductivity become appropriate. The thickness is preferably, for example,
2.5 to 10 μm.

(Intermediate Layer) The intermediate layer constituting the thermal transfer film of the present invention contains at least a heat-fusible substance and a binder resin.

The heat-fusible substance contained in the intermediate layer has a melt viscosity of the heat-fusible substance in a temperature range 15 to 25 ° C. higher than its melting peak temperature (the melting peak temperature specified in JIS K7121-1987) ｛JIS Z8803. −
The viscosity に よ る determined by a cone-plate rotary viscometer (cone low-speed method) defined in 1991 is in the range of 100 to 1000 mPa · s, preferably 100 to 500 mPa · s, and the melting peak temperature of the fusible substance (JIS K7121- 19
87 is in the range of 50 to 110 ° C., preferably 60 to 90 ° C., and the crystallization peak temperature of the heat-fusible substance (the crystallization peak temperature defined in JIS K7121-1987) is 0 to 100. ° C, preferably 20
It is possible to use a substance (subcooling substance) having a temperature in the range of -60 ° C and whose crystallization peak temperature is lower than the melting peak temperature by 10 ° C or more, preferably 30 ° C or more. .

When a plurality of melting peak temperatures measured according to JIS K7121-1987 are observed, the highest peak is defined as the melting peak temperature in the present invention. Similarly, when a plurality of crystallization peak temperatures are observed, the lowest temperature peak is defined as the crystallization peak temperature in the present invention.

The melt viscosity of the heat-fusible substance in a temperature range 15 to 25 ° C. higher than the melting peak temperature is 100 mPa.
-When it is less than s, when forming a hot-melt coloring layer on a base film provided with an intermediate layer by a hot-melt coating method, the hot-melting coloring layer is stably overcoated with good surface quality. It becomes difficult to do. Also, 1000 mPa · s
If the heat transfer temperature exceeds 180 ° C, the fluidity of the heat-fusible substance in a molten state due to the application of printing energy as a liquid is insufficient at the time of peeling the transferred body and the thermal transfer film, Causing an increase in the peeling force F2,
As a result, it is difficult to transfer the hot-melt colored layer to the transfer-receiving member without causing a dropout, which is not preferable.

Further, the melting peak temperature of the heat-fusible substance is 5
If the temperature is lower than 0 ° C., a problem that “entanglement phenomenon” is likely to occur due to preheating of the thermal head occurs. Further, when the crystallization peak temperature of the heat-fusible substance is less than 0 ° C., when the coating liquid for forming the intermediate layer is applied to the base film, the heat is not applied even after the intermediate layer is heated and dried. Because the heat-fusible substance remains in an excessively molten state due to the heat transfer, the intermediate layer may adhere to the substrate film surface (the side opposite to the intermediate layer forming surface side) of the thermal transfer film wound after application, and Even after the fusible colored layer is applied by the hot melt coating method, the state in which the fusible substance remains molten continues excessively, so that there is a problem that the wound thermal transfer film causes blocking. On the other hand, the crystallization peak temperature of the heat-meltable substance is 100 ° C.
When the temperature exceeds 180 ° C., when peeling is performed after printing, under a normal printing environment, the heat-fusible material of the low-viscosity intermediate layer that has melted after printing is crystallized and solidified. , And as a result, white spots occur on the printed matter, making it difficult to form a clear print, which is not preferable. When the temperature difference at which the crystallization peak temperature is lower than the above-mentioned melting peak temperature is less than 10 ° C., the supercooling property of the heat-fusible substance is weakened, and the low-viscosity heat-fusible substance melted after printing is heated. And solidify. Alternatively, the low-viscosity heat-meltable substance melted after printing heating causes an increase in viscosity with a decrease in temperature, causing an increase in the 180 ° hot peel force F2. Printing cannot be formed, 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, dodecanedioic acid and dimer acid, and aromatic dibasic acids such as terephthalic acid, isophthalic acid, orthophthalic acid, naphthalenedicarboxylic acid and 5-sodium sulfoisophthalic acid, tetrahydrophthalic anhydride, hexahydroacid 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. Examples thereof include polyester resins, and a plurality of heat-fusible substances can be used in combination.

The binder resin contained in the intermediate layer has a softening temperature (softening temperature measured by a ring and ball method specified in JIS K2207-1980) of 130 to 400 ° C., preferably 130 to 250 ° C. Things can be used. As such a binder resin,
For example, 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, ionomer resins, styrene resins And the like.

The binder resin used has a softening temperature of 13
If the temperature is less than 0 ° C., it is difficult to appropriately separate the binder resin and the heat-meltable substance in a process of applying and then drying the coating liquid for forming the intermediate layer on the base film,
Since the effect exerted by the super-cooled state of the heat-fusible substance cannot be substantially obtained, an increase in the 180 ° hot peel force F2 is caused, and as a result, the hot-melt colored layer escapes from the transfer-receiving member. It is difficult to transfer without occurrence. Further, since a binder resin having a softening temperature exceeding 400 ° C. is an expensive material in most cases, there is a problem that the production cost of the thermal transfer film becomes excessive.

The thermal transfer film of the present invention may contain carbon black in the intermediate layer. This allows reading the printed content from the printed thermal transfer film (reading the printed content on the transfer film from a copy obtained by copying the shell of the thermally fusible colored layer of the transferred thermal transfer film using a copying machine or the like). ) Becomes difficult, and a function for preventing confidential leakage can be provided. 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.

In order to form the intermediate layer, the above-mentioned materials and a dispersant such as a higher aliphatic alcohol, a phosphoric acid ester and its metal salt, an organic carboxylic acid and its derivative, a low melting point wax and various surfactants are used. 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 such as a gravure coater, a roll coater, a wire bar, etc. It may be applied and dried by means.

The coating amount of the intermediate layer was 0.1% by dry solids.
About 1.0 g / m ² is preferable. 0.1g /
Below the m ^2, no generation of white spots, difficult to clear printed matter can be obtained and on the other hand, when the coating amount exceeds 1.0 g / m ^2, an intermediate layer is too thick, the printing during transfer It is not preferable because the sensitivity is lowered.

(Hot-melting colored layer)
Melt viscosity at 00 ° C. JIS Z8803-199
The viscosity に よ る measured by a cone-plate type rotary viscometer (cone low speed method) defined in 1 is 100 to 300 mPa · s, preferably 1
It is desirable to be in the range of 20 to 250 mPa · s. The melt viscosity at 100 ° C. of the hot-melt colored layer is 10
When the viscosity is less than 0 mPa · s, no further effect of preventing slipping of rough paper is obtained, and the melt viscosity is 300 mPa · s.
If it exceeds 300, the coating aptitude at the time of applying and forming the hot-melt coloring layer by the hot melt coating method may be reduced, and it may be difficult to apply in a good surface state.

In the present invention, the melt viscosity at 100 ° C. of the hot-melt colored layer can be measured as follows.
That is, a facsimile manufactured by Sharp Corporation (UX-F1)
CL), using a 75 μm thick polyethylene terephthalate (PET) film and a thermal transfer film as a measured object, in a copy mode (document type: text, print density: normal) using black color drawing paper as a document. Perform printing.
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 PET film to which the heat-meltable coloring layer obtained as described above is transferred is placed on a hot plate heated to 120 ° C. to melt the heat-meltable coloring layer, and is heated with a spatula or the like. , And cooled to obtain a sample for measurement. Using this sample, J
The melt viscosity at 100 ° C. is measured based on a viscosity measurement method using a cone-plate rotational viscometer (cone low speed method) specified in IS Z8803-1991.

The melting peak temperature of the heat-meltable colored layer (the melting peak temperature specified in JIS K7121-1987) and the melting peak temperature of the above-mentioned heat-meltable substance contained in the intermediate layer (specified in JIS K7121-1987). (Melting peak temperature) is set to be 10 ° C. or less to obtain a printed matter with less omission from rough paper, and the heat-meltable colored layer is fused to the surface of the transfer-receiving body. It is possible to reduce a phenomenon (entanglement phenomenon) of adhering in a thin film shape without performing. For example, when the melting peak temperature of the intermediate layer is 60 ° C., the above effect can be obtained by setting the melting peak temperature of the hot-melt colored layer to 50 ° C. or more and 70 ° C. or less. The effect is more remarkable as the temperature difference is smaller than 10 ° C., and the most preferable printing result is obtained when the temperature difference is 0 ° C. On the other hand, the temperature difference is 10 ° C
If it exceeds, the effect of preventing the entanglement phenomenon cannot be sufficiently obtained.

In the present invention, the melting peak temperature of the hot-melt colored layer can be measured as follows. That is,
Using a facsimile (UX-F1CL) manufactured by Sharp Corporation, using a thermal transfer film as a measurement object on a PET film having a thickness of 75 μm, a copy mode (document type: text, print density: normal) Printing is performed using color paper as an original. 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 PET film to which the hot-melt coloring layer obtained as described above is transferred,
The hot-melt colored layer is melted by being placed on a hot plate heated to 120 ° C., and the hot-melt colored layer is scraped with a spatula or the like, and then cooled to obtain a sample for measurement. Using this sample, the melting peak temperature (the highest peak temperature when there are a plurality of melting peaks) specified in JIS K7121-1987 is measured.

[0048] Such a heat-meltable colored layer comprises a conventionally known coloring agent and a binder.
It can be formed by adding various additives such as vegetable oils, higher fatty acids such as stearic acid, plasticizers, antioxidants and fillers.

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.

The resin component used as a binder includes, 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 coloring agent 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 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 hot-melt colored layer is formed by adding the above colorant component and binder component and, if necessary, mineral oil, vegetable oil, higher fatty acids such as stearic acid,
Add various additives such as plasticizer, antioxidant, filler,
The coating liquid for forming a colored layer prepared by blending a solvent component such as water and an organic solvent is applied by a conventionally known method such as hot melt coating, hot lacquer coating, gravure coating, gravure reverse coating, and roll coating. Also, there is a method of forming using an aqueous or non-aqueous emulsion coating liquid.

The thickness of the hot-melt colored layer should be determined so that the required print density and thermal sensitivity can be balanced.
Preferably, it is in the range of 0.5 to 6.5 g / m ² ,
A range of 5 to 5.5 g / m ² is particularly preferred.

(Surface Layer) In the present invention, a surface layer can be further formed on the above-mentioned hot-melt coloring layer. This surface layer forms part of the hot-melt colored layer,
Forming the surface on the side in contact with the transferred object to seal the printed portion of the transferred object during transfer, improve the storage stability of the thermal transfer film, prevent background contamination, and use the heat-fusible colored layer of the transferred object Has the effect of improving the adhesion to

To form such a surface layer, one kind of substance similar to the wax used in the above-mentioned hot-melt coloring layer is used.
Alternatively, a plurality of combinations can be used as the main component. The surface layer containing the wax as a main component is formed by applying and drying a wax melt, and further applying and drying an aqueous dispersion containing the wax particles, and a conventionally known coating method can be used.

The thickness of the surface layer should be set so as to balance the necessary thermal sensitivity with the filling effect, and is preferably in the range of 0.1 to 1.0 g / m ³ , and in the range of 0.2 to 1.0 g / m ^3. 0.4
A range of g / m ³ is particularly preferred.

(Heat-resistant lubricating layer) A heat-resistant lubricating layer can be provided on the other surface of the base film in order to prevent sticking of the thermal head and improve the slipperiness. 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.

Examples of the binder resin used for the heat-resistant lubricating layer include 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.

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.

[0062]

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 9, 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.

[0064]

[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) Plaxel 220 (manufactured by Daicel Chemical Industries, Ltd.) (2) Hot-melt substance A (3) Hot-melt substance B (4) Hot-melt substance C (5) Plaxel 230 (Daicel Chemical Industries, Ltd.) (6) Praxel 240 (manufactured by Daicel Chemical Industries, Ltd.) (7) Byron 200 (manufactured by Toyobo Co., Ltd.) (8) Byron 600 (manufactured by Toyobo Co., Ltd.) carbon black: average particle size 40 nm ( Mitsubishi Chemical Corporation
Made)

Next, a hot-melt colored layer coating solution having the following composition was heated to 100 ° C. on each intermediate layer, and the thickness was dried to 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 9). However, on the other side of the base film, a heat-resistant lubricating layer coating solution having the following composition was applied by a roll coater, dried, and dried at 0.1 μm.
A heat-resistant lubricating layer having a thickness of m is provided in advance.

(Hot-melting colored layer coating liquid) 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 solution)-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 3 Thermal transfer films (Comparative Samples 1 to 3) were prepared in the same manner as Samples 1 to 9 except that the coating solution for the intermediate layer was changed to the composition shown in Table 1 above. . Regarding the thermal transfer films (Samples 1 to 9 and Comparative Samples 1 to 3) obtained as described above, the 180 ° cold peeling force F1, 180 ° between the intermediate layer and the hot-melt colored layer according to the above-described measurement method. The hot peel force F2 and the difference between F1 and F2 were measured. The thermal transfer films (Samples 1 to 9 and Comparative Samples 1 to 3) were evaluated for print quality (the occurrence of white spots and the occurrence of print entanglement) by the following evaluation methods.

<Print Quality> A facsimile (Telecopier 7033) manufactured by Fuji Xerox Co., Ltd. was used, and the above-mentioned thermal transfer films were applied to printer paper (# 4024, Beck smoothness 32 seconds) manufactured by Xerox Co., Ltd.
Printing was performed in copy mode (document type: text, print density: normal). 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.

(Evaluation of occurrence of white spots)
When the above-mentioned original was copied with each of the thermal transfer films (Samples 1 to 9 and Comparative Samples 1 to 3), printing was performed with the minimum applied voltage that allows visual distinction between capital letters E and B.
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.

(Evaluation of occurrence of print entanglement) After printing with an applied voltage 1.5 V higher than the voltage at the time of the evaluation of the occurrence of white spots, the printing result of uppercase alphabets was visually observed, and the following criteria were used. The evaluation was performed according to the following. A: Almost no crushing of characters due to the occurrence of entanglement was observed, and a very good printed matter was obtained. ○: Slight crushing of characters due to the occurrence of entanglement was observed,
Good printed matter was obtained. X: Character crushing due to the occurrence of entanglement was remarkably observed, and a printed matter having an appearance in which characters and fine lines were significantly crushed was obtained.

(Results) The measurement results and the evaluation results are shown in Table 2 below.

[0074]

[Table 2]

As shown in Table 2, it was confirmed that the thermal transfer film of the present invention (samples 1 to 9) had a print quality of a practical level in the cold peeling process. On the other hand, in the comparative thermal transfer films (Comparative Samples 1 to 3), either the occurrence of white spots or the occurrence of print entanglement was observed, which was not practical.

[0076]

As described in detail above, according to the present invention,
Since the peeling force between the intermediate layer and the heat-meltable colored layer at the portion where the printing energy is applied is set within a predetermined range even when cooled to about room temperature between printing and peeling, the printing energy The heat-meltable colored layer at the portion where the is applied is transferred to the transfer-receiving body without any detachment, and a thermal transfer film capable of performing good printing with less occurrence of white spots even in the cold peeling process is obtained. be able to.

[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 is a perspective view for explaining a test piece used for measuring a 180 ° cold peel force F1 and a 180 ° hot peel force F2 between the intermediate layer and the hot-melt colored layer.

FIG. 3 is a schematic perspective view for explaining a measuring apparatus used for measuring a 180 ° cold peeling force F1 and a 180 ° hot peeling force F2 between an intermediate layer and a hot-melt colored layer.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Thermal transfer film 2 ... Base film 3 ... Intermediate layer 4 ... Hot-melt coloring layer 31 ... 180 degree peeling force measuring device

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Kenichi Asou 1-1-1, Ichigaya-Kagacho, Shinjuku-ku, Tokyo Inside Dai Nippon Printing Co., Ltd. (72) Inventor Masanori Torii 1-1-1, Ichigaya-cho, Shinjuku-ku, Tokyo No. 1 Dai Nippon Printing Co., Ltd. F-term (reference) 2H111 AA14 BA03 BA04 BA07 BA12 BA53 BA63 BA70 BA71

Claims (5)

[Claims] 1. A thermal transfer film having a heat-fusible colored layer provided on a substrate film via an intermediate layer that is not thermally transferred, wherein the 180 ° cold peeling force F1 between the intermediate layer and the heat-fusible colored layer is 1 0.5 to 20.0 g / 50 mm, the 180 ° hot peel force F2 between the intermediate layer and the hot-melt colored layer is within a range of 0 to 5.0 g / 50 mm, and 180 ° cold peel force F1 and 180 °
0.1 g / 50 mm ≦ (F1-
F2) A thermal transfer film, wherein a relationship of ≦ 20.0 g / 50 mm is satisfied. 2. The 180 ° cold peeling force F1 and the 18 °
0.5 g / 50 mm ≦ (F (0 °))
The thermal transfer film according to claim 1, wherein a relationship of 1-F2) ≤ 5.0 g / 50 mm is satisfied. 3. The temperature range in which the intermediate layer contains at least a heat-fusible substance and a binder resin and is higher than the melting peak temperature of the heat-fusible substance by 15 to 25 ° C. (the melting peak temperature specified in JIS K7121-1987). The melt viscosity of the heat-fusible material in {concentration by a cone-plate rotary viscometer (cone low speed method) defined in JIS Z8803-1991} is in the range of 100 to 1000 mPa · s,
The melting peak temperature of the heat-fusible substance (JIS K712)
1-187) (melting peak temperature)
° C, the crystallization peak temperature of the heat-fusible substance (crystallization peak temperature defined in JIS K7121-1987) is in the range of 0 to 100 ° C, and the crystallization peak temperature is the melting point. 10 ° C. or lower than the peak temperature, and further, the softening temperature of the binder resin (JIS
3. The thermal transfer film according to claim 1, wherein a softening temperature measured by a ring and ball method defined in K2207-1980) is in a range of 130 to 400 ° C. 4. 4. 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 any one of claims 1 to 3, wherein the thermal transfer film is within a range of 0 to 300 mPa · s. 5. The melting peak temperature of the heat-meltable colored layer (the melting peak temperature defined in JIS K7121-1987) and the melting peak temperature of the heat-meltable substance contained in the intermediate layer (defined in JIS K7121-1987). The thermal transfer film according to any one of claims 1 to 4, wherein a difference from the melting peak temperature is 10 ° C or less.