JP2606849B2 - Thermal transfer recording medium - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a multi-layered thermal transfer recording medium. More specifically, the present invention relates to a thermal transfer recording medium suitable for applications requiring abrasion resistance, such as bar codes or labels transferred by a label printer or the like.

[Prior art and its problems] Barcodes are widely used as identification symbols or price display symbols for articles. Conventionally, this barcode has been formed by printing. However, recently,
Using a label printer dedicated to bar code transfer, etc., form a desired bar code on a predetermined label by thermal transfer,
The label to which the barcode has been transferred is often attached to a product and used. In this case, a special thermal transfer recording medium such as a thermal transfer recording medium for a bar code is not used, but a normal thermal transfer recording medium is used.

However, a bar code formed by a normal thermal transfer recording medium is formed in a state in which each bar is formed in a state in which a coloring material is uniformly dispersed in a binder component such as a heat-fusible substance and a thermo-softening resin. Has the property of being softer than those formed by printing. For this reason, the bar code usually formed by the thermal transfer recording medium is attached to the outside of the product packaging and comes into contact with other articles, so that the coloring material protrudes from the printed portion, and the bar code is not formed. May contaminate parts (occurrence of soiling). Furthermore, when reading barcodes,
In some cases, scanning is performed while the sensor is in contact with the barcode, and the repetition of this reading operation may cause the color material to protrude from the bar portion and cause background contamination.

Bar codes require that the width of each bar be accurate to the order of microns. Therefore, in a barcode formed using a normal thermal transfer recording medium, there has been a problem that a reading error frequently occurs due to a color material protruding. That is, according to the study of the present inventor, when an article with a barcode formed by transfer using a normal thermal transfer recording medium is handled under normal conditions and then the barcode is read, the error occurrence rate is reduced. It turns out that it can reach as much as 30%.

[Object of the Invention] An object of the present invention is to provide a thermal transfer recording medium having good scratch resistance.

In particular, an object of the present invention is to provide a thermal transfer recording medium excellent in abrasion resistance suitable for a label printer for forming a bar code or the like.

[Means for Achieving the Object] The configuration of the present invention for achieving the object includes a support, a first heat-softening layer containing a heat-fusible substance laminated on the support, and A heat-sensitive transfer recording medium having at least two layers of a second heat-softening layer containing a coloring material laminated on one heat-softening layer and a heat-softening layer, wherein the first heat-softening layer has a thickness of 25%.
A thermal transfer recording medium characterized in that the penetration at 1 ° C. is 1 or more and 3 or less, and that the second heat-softening layer contains substantially all of the coloring material.

-Support-The support used in the thermal transfer recording medium of the present invention preferably has heat resistance, high dimensional stability and high surface smoothness.

As a material for forming the support, for example, papers such as plain paper, condenser paper, laminated paper and coated paper,
Examples thereof include resin films such as polyethylene, polyethylene terephthalate, polystyrene, polypropylene, and polyimide, composites of paper and resin films, and metal sheets such as aluminum foil, and any of these can be suitably used.

The thickness of the support is usually 60 μm or less for obtaining good thermal conductivity. In the present invention, in particular, 1.5
Those having a diameter within a range of from 15 to 15 μm are preferred. Surface treatment such as corona discharge treatment, glow discharge treatment, other electric shock treatment, flame treatment, ultraviolet irradiation treatment, oxidation treatment and saponification treatment on the surface of the support to enhance the adhesion to the heat softening layer Or the like, or may be subjected to a subbing process.

The support may have a backing layer on one surface.

—Thermal Softening Layer— The thermal transfer recording medium of the present invention has a thermal softening layer on the above support. The heat-softening layer is composed of at least two layers, a first heat-softening layer laminated on the support and a second heat-softening layer laminated on the first heat-softening layer.

FIG. 1 shows a sectional view of an example of the thermal transfer recording medium of the present invention.

In FIG. 1, reference numeral 10 denotes a support. A first thermosoftening layer 11 is laminated on the support 10, and a second softening layer 12 is laminated on the first thermosoftening layer 11.

In FIG. 1, the first heat-softening layer 11 is
Although directly laminated on the support, the first heat-softening layer 11 may be laminated on the support 10 via a release layer or an undercoat layer (not shown).

In FIG. 1, the second softening layer 12 is directly laminated on the first heat softening layer 11, but the second softening layer 12 is formed via an adhesive layer (not shown). The heat-softening layer 11 may be laminated.

Further, the first thermosoftening layer and the second thermosoftening layer may be composed of, for example, two or more thermosoftening layers having different compositions.

(First heat-softening layer) The first heat-softening layer is a layer containing a heat-fusible substance and is a layer containing substantially no coloring material. The content of the heat-fusible substance in this layer is usually at least 50% by weight of the total weight of this layer. If the amount is less than 50% by weight, the releasability of this layer at the time of transfer may decrease, and the transfer performance may decrease. In particular, in the present invention, the content is preferably 70% by weight or more, more preferably 85% by weight or more. By doing so, the scratch resistance is improved. It should be noted that the fact that the color material is not substantially contained is determined based on a bar code reading device or the like in this layer, and a color material having a density that can be read by this device is actively used. It means that it is not added. Therefore, addition to such an extent that the discriminating power is not affected and mixing of a coloring material in a manufacturing process are not excluded.

The penetration at 25 ° C. of the first heat-softening layer is 1 or more and 3
It is as follows. Here, the penetration is a value measured by a method specified in ASTM-D-14-1. In the present invention, the penetration is measured by the above method.

If the penetration of the first heat-softening layer is higher than 3, the function of the first heat-softening layer after transfer as a protective layer is reduced, so that sufficient abrasion resistance is imparted to the transfer body. Can not. In particular, in the present invention, the penetration of this layer is 1.0 to 2.5
Within this range, very good abrasion resistance is exhibited. For example, printed barcodes do not stain the ground due to contact, and read errors hardly occur. When the penetration is lower than 1.0, the scratch resistance of this layer itself is good, but a remarkable imbalance occurs in the balance of rigidity with the second heat-softening layer, and the transfer portion is different from other articles and the like. Contact may cause delamination between the first and second thermosoftening layers.

There are various methods for controlling the penetration of the first heat-softening layer as described above, and a high-melting material (hard wax or hard-melting It is advantageous to use a method using an active substance). The hard thermofusible substance that can be effectively used in the first thermosoftening layer usually has a penetration of 4 or less.

Examples of the hard heat-fusible substance that can be used in the present invention include carnauba wax, synthetic ester wax and hard petroleum wax, which may be used alone or in such a manner that the penetration is as described above. They can be used in combination. Specific examples include carnauba wax, montan wax, sasol wax (produced by Kato Yoko Co., Ltd.), synthetic ester wax (produced by Hoechst,
Basf), polyethylene wax (Sanyo Chemical Co., Ltd.)
Manufactured by Mitsui Petrochemical Co., Ltd., manufactured by Bareco Co., Ltd.) and oxidized wax (manufactured by Nippon Seiro Co., Ltd.). These can be used alone or in combination of two or more.

In the present invention, the penetration can also be adjusted by using another heat-fusible substance (soft heat-fusible substance, soft wax) together with the above-mentioned hard heat-fusible substance. However, in this case, the content of the hard heat-meltable substance in the heat-meltable substance is
Preferably, the content is 50% by weight or more.

Specific examples of the soft heat-fusible substance that can be used here include vegetable waxes such as wood wax, ouriculi wax and Espal wax, animal waxes such as beeswax, insect wax, shellac wax and spermaceti, paraffin wax and Soft petroleum waxes such as microcrystalline wax, waxes such as mineral waxes such as ozokerite and ceresin, palmitins, higher fatty acids such as stearic acid, margaric acid and behenic acid, palmityl alcohol, stearyl alcohol, behenyl alcohol, marganyl alcohol, Higher alcohols such as myricyl alcohol and eicosanol; amides such as acetamide, propionamide, palmitic amide, stearic amide and amide wax; and stearylamine, behenylamido And higher amines such as palmitylamine. These may be used alone or in combination.

Further, the first thermosoftening layer may include a thermoplastic resin in addition to the above-mentioned heat-fusible substance.

Examples of the thermoplastic resin that can be used in the present invention, ethylene copolymer, polyamide resin, polyester resin, polyurethane resin, polyolefin resin, acrylic resin, vinyl chloride resin, cellulose resin, Resins such as rosin resin, ionomer resin and petroleum resin, elastomers such as diene copolymer, natural rubber, styrene butadiene rubber, isoprene rubber and chloroprene rubber, ester gum, rosin maleic resin, rosin phenol resin and hydrogenated Rosin derivatives such as rosin, and softening points of phenolic resins, terpene resins, cyclopentadiene resins, aromatic hydrocarbon resins, etc.
And the like.

Hereinafter, preferred thermoplastic resins that can be used in the first thermosoftening layer will be described.

As the acrylic resin, for example, a monobasic carboxylic acid such as (meth) acrylic acid or an ester thereof,
An acrylic resin obtained by polymerizing at least one compound copolymerizable therewith with a known method such as emulsion polymerization can be used.

Examples of the carboxylic acid or its ester used at this time include (meth) acrylic acid, (meth) acrylic acid methyl ester, (meth) acrylic acid ethyl ester,
Isopropyl (meth) acrylate, butyl (meth) acrylate, isobutyl (meth) acrylate, amyl (meth) acrylate, hexyl (meth) acrylate, octyl (meth) acrylate, (meta) ) Acrylic acid-2-ethylhexyl ester, (meth) acrylic acid decyl ester,
Dodecyl (meth) acrylate, hydroxyethyl (meth) acrylate and hydroxyethyl (meth) acrylate can be mentioned. Examples of the above copolymerizable compound include vinyl acetate, vinyl chloride, vinylidene chloride, maleic anhydride, fumaric anhydride, styrene, 2-methylstyrene, chlorostyrene, acrylonitrile, vinyltoluene, N-methylol ( Examples thereof include (meth) acrylamide, N-butoxymethyl (meth) acrylamide, vinylpyridine, and N-vinylpyrrolidone, and these can be used alone or in combination of two or more.

Examples of the diene-based copolymer include a copolymer of a diene-based monomer such as butadiene, isoprene, isobutylene, and chloroprene with the above-described copolymerizable compound. Specific examples of this copolymer include butadiene-styrene copolymer, butadiene-styrene-vinylpyridine copolymer, and butadiene-
Examples thereof include acrylonitrile copolymer, chloroprene-styrene copolymer and chloroprene-acrylonitrile copolymer.

As the ethylene-based copolymer, for example, ethylene-
Vinyl acetate copolymer, ethylene-ethyl acrylate copolymer, ethylene-methyl methacrylate copolymer, ethylene-isobutyl acrylate copolymer, ethylene-acrylic acid copolymer, ethylene-vinyl alcohol copolymer,
Examples include an ethylene-vinyl chloride copolymer and an ethylene-acrylate metal salt copolymer.

In the present invention, an acrylic resin and / or an ethylene copolymer is particularly preferable as the thermoplastic resin that forms the first thermosoftening layer together with the above-mentioned heat-fusible substance.

When using a thermoplastic resin, the content of the thermoplastic resin in the first thermosoftening layer is usually 50% of the total weight of this layer.
% By weight. It is preferably at most 30% by weight, particularly preferably at most 15% by weight.

(Second heat-softening layer) The second heat-softening layer is a layer containing substantially all of the coloring material. That is, in the thermal transfer recording medium of the present invention, substantially all of the coloring material is contained in this layer, and the coloring material is substantially contained in other layers, for example, the first heat-softening layer. Not. In the second thermosoftening layer, the coloring material usually exists in a state of being dispersed in the thermofusible substance and the thermoplastic resin.

This second heat-softening layer is a layer having a function of fixing a coloring material on a transfer-receiving medium such as a bar code label, and transfers a hot melt or the like containing the coloring material during thermal transfer. The ink is permeated into the fibers of the medium to form a print with less occurrence of voids and the like, and after the transfer, the coloring material is fixed to the medium to be transferred. In other words, at the time of transfer, the properties of the heat-fusible material melted to transport the color material into the medium to be transferred dominantly act, and after the transfer, the thermoplastic resin is dominant to fix the color material. Acts in a way.

In consideration of such an effect, the content of the thermoplastic resin with respect to the total weight of the layer is preferably set to 5% by weight or more. It is particularly preferred to be within the range of 10 to 50% by weight. The content of the heat-fusible substance is usually 30 to
It is in the range of 80% by weight.

Further, the content of the coloring material is usually in the range of 5 to 30% by weight.

As the thermoplastic resin in this layer, those used in the first thermosoftening layer can be used.

Further, as the heat-fusible substance, the above-mentioned substances used in the first heat-softening layer can be used. In this case, both a hard heat-meltable substance and a soft heat-meltable substance can be used. However, considering the properties of this layer,
It is desirable that the penetration of this layer be higher than that of the first heat-softening layer (the penetration should be higher than 3),
Therefore, usually, the content of the soft thermofusible material is set higher than the content in the first thermosoftening layer.

As the coloring material, commonly used pigments such as inorganic pigments and organic pigments and dyes can be used.

Examples of inorganic pigments include titanium dioxide, carbon black, zinc oxide, Prussian blue, cadmium sulfide and iron oxide, and chromates of lead, zinc, barium and calcium. Examples of organic pigments include azo-based, thioindigo-based, anthraquinone-based, anthranthrone-based, and triphenedioxazine-based pigments, vat dye pigments, phthalocyanine pigments, metal (eg, copper) phthalocyanine and its derivatives, and quinacridone pigments.

Examples of organic dyes include acid dyes, direct dyes, disperse dyes, oil-soluble dyes, and metal-containing oil-soluble dyes.

-Preparation method of each layer-The thermal transfer recording medium of the present invention is prepared by dissolving or dispersing a substance forming the first heat-softening layer and the second heat-softening layer in an organic solvent to prepare a coating solution. A method in which the coating liquid for the first heat-softening layer and the coating liquid for the second heat-softening layer are coated on the support in this order can also be adopted. However, in the present invention, at least the second heat-softening layer is preferably formed by employing an aqueous coating method.

 First, a first thermosoftening layer is formed on a support.

The first heat-softening layer is formed by dissolving or dispersing the constituents of this layer in an organic solvent and applying a coating solution prepared (solvent coating method). A method of applying the melt (hot-melt coating method) and a method of preparing an aqueous coating liquid prepared by dispersing the constituents of this layer in water and applying the coating liquid (aqueous coating method) And the like, and can be formed by coating using a normal coating apparatus.

The first thermosoftening layer is a dry thickness, usually 0.5 to 8.0 μm
(Preferably, 1 to 4 μm). If the thickness is less than 0.5 μm, the abrasion resistance may be insufficient, and if the thickness is more than 8.0 μm, the sensitivity may decrease.

The second heat-softening layer is preferably formed by using an aqueous coating method. That is, by applying the second heat-softening layer to the aqueous coating, the coloring material contained in the first heat-softening layer does not migrate into the second heat-softening layer at the production stage, The conductive layer and the second thermosoftening layer become discontinuous, and the compartments of both layers become clear.

When the second heat-softening layer is formed by using the aqueous coating method, the aqueous emulsion used is prepared by dispersing the components forming this layer in water to prepare aqueous emulsions of the respective components, and then mixing them. It can be prepared using a method such as a method in which at least a part of the forming components are previously mixed in the absence of water, and water is added thereto.

The aqueous emulsion preferably contains a fluorine-based surfactant. The fluorinated surfactant may be blended when preparing the above mixture or may be blended into the obtained aqueous emulsion. This fluorine-based surfactant can effectively prevent the blocking phenomenon of the second heat-softening layer, and the affinity of the aqueous emulsion for the surface of the first heat-softening layer because the surface tension of the aqueous emulsion is favorably reduced. The so-called “repelling” at the time of application can be effectively prevented. As the fluorinated surfactant, a usual one can be used.

The content of the fluorine-containing surfactant in this layer is preferably in the range of 0.05 to 3% by weight, and more preferably in the range of 0.1 to 2% by weight, based on the total solid content of the heat-softening layer. It is particularly preferred that

In preparing the aqueous emulsion, a surfactant may be further added to promote uniform mixing of the thermofusible substance and the thermoplastic resin.

In this case, the surfactant is preferably used in a blending ratio of 20% by weight or less based on the total weight of the heat-fusible substance and the thermoplastic resin.

Here, as the surfactant, a nonionic surfactant,
Any of an anionic surfactant, a cationic surfactant, and an amphoteric surfactant can be used.

The amount of water used in the preparation of the aqueous emulsion may be within the range used for the preparation of a general aqueous emulsion. In particular, in the present invention, the content of the active ingredient in the aqueous emulsion is 5 to 50% by weight. % Water should be added.

The aqueous emulsion may further contain a thickener such as sodium polyacrylate, a substance (eg, colloidal silica) that improves the properties of the second thermosoftening layer.

The method of applying the aqueous emulsion is not particularly limited, and a known method such as a method using a wire bar or the like can be employed.

The second thermosoftening layer is usually set so that the dry thickness of the second thermosoftening layer is in the range of 0.6 to 5.0 μm. In particular, it is preferable to apply the coating so that the dry thickness is in the range of 1.0 to 4.0 μm.

In particular, in the present invention, it is preferable that the thickness of the second thermosoftening layer is smaller than the thickness of the first thermosoftening layer. That is, after the transfer, the first heat-softening layer comes out to the surface, and acts as a layer for protecting the surface of a transfer material such as a barcode that has been revealed by the coloring material contained in the second heat-softening layer. ,
By increasing the thickness of the first heat-softening layer, the scratch resistance of the transferred product is improved.

The thermal transfer recording medium of the present invention can be cut into a long shape, for example, according to the transfer width of a bar code or the like, and can be used as a thermal transfer ribbon, or of course, in a sheet form. .

-Method of Use- The thermal transfer recording medium of the present invention can be suitably used for barcode transfer or label printing using a label printer or the like.

FIG. 2 shows an example of a cross section of a barcode recorded using the thermal transfer recording medium of the present invention.

In FIG. 2, 23 is a transfer medium. The barcode 24 is transferred onto the transfer medium. The bar code 24 formed by the heat-sensitive transfer recording medium of the present invention includes a second heat-softening layer 22 containing a color material on a transfer-receiving medium, and a color material on the second heat-softening layer 22 substantially. The first heat-softening layer 21 does not include the first heat-softening layer 21.

It is usually near the surface of the first heat-softening layer 21 that a transfer body such as a barcode is scratched by contact with another article or the like. The bar code formed using the thermal transfer recording medium of the present invention has a low penetration near the surface of the first heat-softening layer 21 and has good scratch resistance. Further, since the color material is not included in this portion, even if the first heat-softening layer moves to, for example, a portion 25 of the medium to which the image is not transferred, due to contact or the like, background contamination does not occur in this portion. Therefore, occurrence of a reading error can be effectively prevented.

[Effects of the Invention] In the thermal transfer recording medium of the present invention, since the penetration of the first heat-softening layer which appears on the surface when transferred is low, this portion is hardly damaged by contact or the like.

Further, substantially all of the coloring material is contained in the second heat-softening layer which does not appear on the surface when transferred, and the first softening layer on the surface contains substantially no coloring material. Even when the portion is contacted, only the surface portion of the first heat-softening layer that does not contain the coloring material is subjected to abrasion, and the background material due to the overflow of the coloring material does not occur.

Therefore, it is possible to perform transfer with very good abrasion resistance, such as using the thermal transfer recording medium of the present invention and transferring a barcode with less occurrence of reading errors.

[Examples] In the examples and comparative examples shown below, the designation "parts" indicates "parts by weight".

Example 1 The following first heat-softening layer coating composition (I) was coated on a 3.5 μm polyethylene terephthalate film with a dry film thickness of 3.0.
Hot melt coating was performed to a thickness of μm to form a first heat-softening layer of the thermal transfer recording medium of the present invention. The penetration of the formed first heat-softening layer was 2.0.

First heat-softening layer coating composition (I) Carnauba wax [melting point 70 ° C] ... 40 parts Ethylene-vinyl acetate copolymer ... 10 parts Polyethylene wax [melting point 100 ° C] ... 25 parts Paraffin wax [melting point 70] ° C] ... 25 parts Next, an aqueous emulsion was prepared by dispersing in water to the coating composition for the second thermosoftening layer coating composition shown below, and the dried film thickness was adjusted to 2.0 µm using a wire bar. Then, an aqueous coating was applied on the first heat-softening layer to form a second heat-softening layer, thereby producing a thermal transfer recording medium of the present invention.

Second heat-softening layer coating composition (weight in terms of solid content) Carbon black aqueous dispersion: 40 parts Paraffin aqueous emulsion: 10 parts Acrylic resin emulsion: 25 parts Carnauba wax emulsion: 25 parts (Comparative Example 1) In Example 1, the first heat-softening layer coating composition (I)
Was used in the same manner except that the first heat-softening layer coating composition (I-1C) described below was used to produce a thermal transfer recording medium. The penetration of the formed first heat-softening layer was 6.0.

First heat-softening layer coating composition (I-1C) Ethylene-vinyl acetate copolymer 10 parts Paraffin wax [melting point 70 ° C] 90 parts (Comparative Example 2) In Example 1, first heat softening Coating composition (I)
Was used in the same manner except that a first heat-softening layer coating composition (I-2C) described below was used to produce a thermal transfer recording medium. The penetration of the formed first heat-softening layer was 7.4.

First thermal softening layer coating composition (I-2C) Microcrystal wax 50 parts Paraffin wax [melting point 70 ° C] 50 parts (Example 2) In Example 1, the first thermal softening layer coating composition Thing (I)
Instead of using the first heat-softening layer coating composition (II) described below, the coating thickness of the first heat-softening layer is 1.
A thermal transfer recording medium of the present invention was produced in the same manner except that the thickness was changed to 5 μm. The penetration of the formed first heat-softening layer is 1.8
Met.

First thermal softening layer coating composition (II) Carnauba wax [melting point 70 ° C] ... 70 parts Paraffin wax [melting point 70 ° C] ... 20 parts Ethylene-vinyl acetate copolymer ... 10 parts (Example 3) In Example 1, the first heat-softening layer coating composition (I)
Was used in the same manner except that the first heat-softening layer coating composition (III) described below was used to produce a thermal transfer recording medium of the present invention. The penetration of the formed first heat-softening layer is
It was 2.5.

First heat-softening layer coating composition (III) Carnauba wax [melting point 70 ° C] ... 60 parts Paraffin wax [melting point 70 ° C] ... 30 parts Ethylene-vinyl acetate copolymer ... 10 parts (Comparative Example 3) In Example 3, the first heat-softening layer coating composition (II
A heat-sensitive transfer recording medium was produced in the same manner except that the first heat-softening layer coating composition (III-C) described below was used instead of I). The penetration of the formed first heat-softening layer is
Was 3.5.

First thermal softening layer coating composition (III-C) Carnauba wax [melting point 70 ° C] 30 parts Paraffin wax [melting point 70 ° C] 60 parts Ethylene-vinyl acetate copolymer 10 parts (Examples) 4) In Example 1, the first heat-softening layer coating composition (I)
Instead of using the first heat-softening layer coating composition (IV) described below, the coating thickness of the first heat-softening layer is 2.
A thermal transfer recording medium of the present invention was produced in the same manner except that the thickness was changed to 5 μm. The penetration of the formed first heat-softening layer is 1.8
Met.

First thermal softening layer coating composition (IV) Carnauba wax [melting point 70 ° C] 70 parts Paraffin wax [melting point 70 ° C] 20 parts Ethylene-vinyl acetate copolymer 10 parts (Comparative Example 4) In Example 1, the first heat-softening layer coating composition (I)
Instead of using the first heat-softening layer coating composition (IV-C) described below, the thermal transfer was performed in the same manner except that the coating thickness of the first heat-softening layer was changed to 2.5 μm in dry thickness. A recording medium was manufactured. The penetration of the formed first heat-softening layer was 3.5.

First thermal softening layer coating composition (IV-C) Carnauba wax [melting point 70 ° C]… 40 parts Paraffin wax [melting point 70 ° C] 53 parts Ethylene acrylate copolymer 3 parts (Example 5) 1, the first heat-softening layer coating composition (I)
Was used in the same manner except that the first heat-softening layer coating composition (V) described below was used to produce a thermal transfer recording medium of the present invention. The penetration of the formed first heat-softening layer is 2.
It was five.

First thermal softening layer coating composition (V) Polyethylene wax ... 50 parts Synthetic ester wax ... 30 parts Selemin wax ... 20 parts [Evaluation] Thermal transfer recording media obtained in the above Examples and Comparative Examples Was attached to a label printer, and a bar code was transferred.

After the transferred barcode portion was abraded 50 times with a 50 g weighted glass pen, the degree of background contamination of the portion where the barcode was not transferred was measured with a microdensitometer.

 The results are shown in Table 1.

 The meanings of the symbols in Table 1 are as follows.

Symbol Background dirt…: The measured value of the microdensitometer is almost 0.

…: The measured value of the icrodensitometer is within a range of more than 0 and less than 0.3.

×: The measured value of the microdensitometer is 0.3 or more.

[Brief description of the drawings]

FIG. 1 is a sectional view of an example of the thermal transfer recording medium of the present invention. FIG. 2 is a cross-sectional view showing a cross section of a barcode formed using the thermal transfer recording medium of the present invention. 10 ... Support 11,21 ... First heat-softening layer 12,22 ... Second heat-softening layer 23 ... Transfer medium 24 ... Bar code 25 ... Parts not transferred

Claims (5)

(57) [Claims] 1. A first heat-softening layer containing a heat-fusible substance laminated on a support, and a second heat-softening layer containing a coloring material laminated on the first heat-softening layer. A heat-sensitive transfer recording medium having at least two thermosoftening layers of a heat-sensitive layer,
Thermal transfer recording wherein the penetration degree of the first thermosoftening layer at 25 ° C. is 1 or more and 3 or less, and substantially the entire amount of a coloring material is contained on the second thermosoftening layer. Medium. 2. The thermal transfer recording medium according to claim 1, wherein the thickness of the first thermosoftening layer is larger than the thickness of the second thermosoftening layer. 3. The heat-sensitive transfer recording medium according to claim 1, wherein the first heat-softening layer and the second heat-softening layer are substantially discontinuous layers. 4. The first thermosoftening layer comprises a soft thermofusible substance and a hard thermofusible substance, and the content of the hard thermofusible substance in the layer is based on the total weight of the layer. 2. The thermal transfer recording medium according to claim 1, wherein the content is 50% by weight or more. 5. A thermal transfer recording medium according to claim 1, wherein said thermal transfer recording medium is a thermal transfer recording medium for a label printer.
Item 6. The thermal transfer recording medium according to any one of the above items.