JPH04347693A - Thermal transfer recording medium - Google Patents

Abstract

PURPOSE:To provide a thermal transfer recording medium which can perform dull-finished printing is clear in printing quality of, especially, a ladder bar code (a bar code to be printed at 90 deg. to an advance direction of the thermal transfer recording medium) while proper printing quality is being maintained, and is free from occurrence of ink peeling even at low temperature. CONSTITUTION:For a thermal transfer recording medium wherein a mat layer 12 having a pigment and resin as main components, a peeling layer 13, and an ink layer 14 are formed on a base material, (1) shear strength by combining the peeling layer 13 and the ink layer 14 is made 30-70gf/cm at 5 deg.C and adhesive strength to the mat layer 3 is made 1.5-5.0gf/cm or (2) a portion or all of the pigment of the mat layer 12 is made to be silica powder which is surface treated with silicone resin of 0.1-2.0mum particle size.

Description

[Detailed description of the invention]

0001

[Field of Industrial Application] The present invention relates to a thermal transfer recording medium particularly for barcode printers, and more specifically, the ink layer does not peel off when not in use at low temperatures, has excellent storage stability, and has a rudder pattern. Thermal transfer recording media that can clearly print barcodes (barcodes printed at 90 degrees to the direction of travel of the thermal transfer recording medium) and make the barcodes matte so that they can be read accurately by scanners. Regarding.

0002

[Prior Art] Barcode images printed using thermal transfer recording media have a glossy ink and cannot be read accurately with a barcode scanner, so the surface is roughened, so-called matte. It is proposed that. Specific thermal transfer recording media include (1) one in which a heat-melt ink layer consisting of a colorant and a binder is provided on a support, and (2) the base material has a rough surface and an ink layer is formed on it. (3) A roughened matte layer is provided on a base material, and an ink layer is provided thereon. (4) An ink layer is attached to a support via a release layer mainly composed of wax. It is known that the

However, in the thermal transfer recording medium of the type (1), the ink layer itself must contain a large amount of pigment such as carbon black in order to obtain an appropriate print density, and the transfer surface after printing is free of pigment. The disadvantage is that the receiving paper itself becomes exposed and becomes dirty when rubbed with cardboard or a finger, or traced with a pen scanner, making it impossible to read the barcode. A sufficient effect cannot be obtained with the thermal transfer recording medium of the type (2). The surface of the thermal transfer recording medium of type (3) is generally roughened by mixing silica into the matte layer, but if silica is mixed in to the extent that the surface of the transferred ink becomes sufficiently matte, the matte layer and the substrate become rough. Since the adhesion of the ink deteriorates, there is a problem that the matte layer is transferred together with the ink. Furthermore, the above (4
) type of thermal transfer recording medium has a peeling layer.
Pigments, etc. are not exposed on the transfer surface after printing, and it shows a better effect than the one described in (3) above in terms of abrasion resistance, but because the wax, which is the main component of the release layer, is soft, sufficient effects cannot be obtained. In addition, there are other problems such as gloss on the printed surface, making it difficult to read the barcode.

In addition, as pointed out earlier, the binder of the ink layer (3) and the binder of the release layer (4) are mainly composed of wax with low plasticity; Therefore, the adhesion with resins often used as matte layers, such as unsaturated polyester resins and epoxy resins, is extremely low, resulting in inconveniences such as the ink layer and release layer peeling off from the support due to external mechanical force. . This phenomenon is particularly noticeable at low temperatures (5° C.).

Furthermore, in the thermal transfer recording medium of type (4), as mentioned above, the release layer is mainly composed of wax with low plasticity, so the combined shear strength of the release layer and the ink layer is low. As a result, when a ladder barcode is printed using a barcode printer or the like, a drop-off phenomenon (a phenomenon in which areas not energized by the thermal head are also transferred) results in unclear printing. Therefore, there is a drawback that laser scanners cannot read barcodes.

[0006]

[Problems to be Solved by the Invention] The present invention is a thermal transfer method that can perform matte printing, maintains the original printing quality, has clear printing quality especially for ladder barcodes, and does not peel off ink even at low temperatures. It provides a recording medium.

[0007]

[Means for Solving the Problems] One aspect of the present invention is to provide a matte layer containing pigment and resin as the main components on a support, provide a release layer containing wax as the main component on top of the matte layer, and further provide a release layer containing wax as the main component. In a thermal transfer recording medium provided with an ink layer containing a colorant, wax, and resin as main components, the shear strength of the matte layer and ink layer combined is 30 to 70 gf/at 5°C.
cm, and the adhesive strength to the mat layer is 1.cm at 5°C.
It is characterized by being 5 to 5.0 gf/cm.

Another aspect of the present invention is to provide a matte layer containing pigment and resin as the main components on a support, provide a release layer containing wax as the main component, and further apply a colorant, In a thermal transfer recording medium provided with an ink layer containing wax and resin as main components, part or all of the pigment in the release layer is surface-treated with a silicone resin having a particle size of 0.1 to 2.0 μm. Silica particles It is characterized by being

[0009] The invention will now be explained in more detail with reference to the accompanying drawings. FIG. 1 is a sectional view of a thermal transfer recording medium 1 according to the present invention. In this drawing, 11 is a film-like support, 12 is a matte layer, 13 is a release layer, 14
15 represents an ink layer (heat-melting ink layer), and 15 represents a heat-resistant protective layer.

Examples of the support 11 include films of relatively heat-resistant plastics such as polyester, polycarbonate, triacetyl cellulose, nylon, and polyimide, as well as glassine paper, condenser paper, metal foil, etc. The diameter is about 2 to 15 μm, preferably 3 to 1
It is in the range of 0 μm. The surface of the support 11 in contact with the thermal head (the surface opposite to the ink layer 14) may be coated with silicone resin, fluororesin, polyimide resin, epoxy resin, or phenol resin, if necessary. By providing a heat-resistant protective layer 15 made of , melamine resin, nitrocellulose, etc., the heat resistance of the support 11 can be improved, or a support material that could not be used conventionally can be used.

[0011] As the pigment, which is a material for making the matte layer 12 surface, conventionally known pigments such as carbon black, silica, alumina, calcium carbonate, iron oxide, magnesium oxide, and talc can be used, and in particular, silicone Silica particles (particle size 0.1-2 μm) surface-treated with
Specially surface-treated particles such as those may also be used. The silicone used for surface treatment of the above silica particles is as follows:
Examples include silicone KF-96 and silicone KF99 (manufactured by Shin-Etsu Chemical Co., Ltd.). In addition, as a method for surface treating silica particles with silicone, for example,
Surface treatment can be achieved by soaking silica in a % carbon tetrachloride solution, air drying, and then baking at 300° C. for about 5 minutes.

The binder for bonding the pigment to the base plastic film to form the matte layer 12 may be a vinyl chloride-vinyl acetate copolymer, a thermoplastic resin such as ethyl cellulose, an unsaturated polyester resin, or an epoxy resin. Thermosetting resins such as, etc. can be used. The mixing ratio (weight ratio) of these pigments (including silica particles surface-treated with silicone) and binder is 1:10 to 5:1, but preferably 1:10 to 5:1.
:2 to 4:1.

The thickness of the mat layer 12 is suitably 0.2 to 3 μm, preferably 0.5 to 1.5 μm. If it is thinner than 0.2 μm, the matting effect will be lost, and if it exceeds 3 μm, there will be a problem of decreased thermal sensitivity.

Furthermore, it is desirable that the adhesive strength of the matte layer 12 to the support 11 at 5° C. be greater than that of the release layer 13 and the ink layer 14 combined. This corresponds to the support 11 of the mat layer 12 at 5°C.
This is because if the adhesive strength to the ink layer is lower than the combined strength of the peeling layer 13 and the ink layer 14, when printing is performed, the matte layer 12 may be transferred, resulting in a problem that the printing does not become matte.

[0015] The peeling layer 13 is mainly formed at a temperature of 40 to 100°C.
Paraffin wax with a melting point of Oil, lanolin, wood wax, sorbitan stearate, sorbitan palmitate, stearyl alcohol, polyamide wax, oleylamide, stearylamide, hydroxystearic acid, margaric acid, lauric acid, myristic acid, palmitic acid, stearic acid, fromenic acid, behenin It is composed of waxy substances such as acids, synthetic ester waxes, and synthetic alloy waxes, but these may also contain elastomers such as rubber, polyvinyl butyral, vinyl chloride-vinyl acetate copolymer resins, nitrocellulose, Epoxy resin, ethylene-vinyl acetate copolymer resin, ethylene-α-olefin copolymer resin, α-olefin-maleic anhydride copolymer resin, ethylene-methacrylic acid copolymer resin, ethyl cellulose, rosin derivative, petroleum resin, styrene resin An appropriate amount of at least one resin such as and/or oils (mineral oil, vegetable oil, etc.) may be mixed.

The thickness of the release layer 13 is 0.5 to 10 μm,
Preferably it is 1 to 3 μm. If it is thinner than 0.5μm,
The function of the release layer 13 is degraded, and the transferability to paper with relatively low smoothness is degraded. On the other hand, if it exceeds 10 μm, the adhesive strength decreases and the ink layer peels off at low temperatures (5 to 10° C.). Furthermore, as the thickness of the release layer 13 increases, the shear strength increases, which may lead to poor transfer.

In one thermal transfer recording medium of the present invention, the combined shear strength of the release layer 13 and the ink layer 14 is 5.
The adhesive strength to the mat layer 3 must be 30 to 70 gf/cm at a temperature of 1.5 to 5.0 gf/cm.

When the combined shear strength of the release layer 13 and the ink layer 14 is 30 gf/cm or less at 5° C. and the adhesive strength to the matte layer 12 is 1.5 gf/cm or less,
Not only does the ink layer 14 peel off at low temperatures (5 degrees Celsius), but even at normal temperatures (20 to 25 degrees Celsius), when ladder barcodes are printed with a barcode printer, the ink layer 14 also peels off, making it difficult to read with a laser scanner. There is a possibility that it will not be possible. On the other hand, the ink layer 14 is attached to the release layer 13.
The combined shear strength is 70 gf/cm or more at 5°C, and the adhesive strength to the mat layer 12 is 5.0 gf/cm.
cm or more, the adhesive force becomes greater than the adhesive force to the transfer paper, and as a result, phenomena such as poor transfer often occur.

[0019] Preferably, an elastomer such as rubber can be used as a material for achieving such desirable conditions. Examples of elastomers such as rubber include synthetic rubbers such as butadiene rubber, styrene-butadiene rubber, nitrile rubber, nitrile-butadiene rubber, high styrene rubber, isoprene rubber, acrylic rubber, epichlorohydrin rubber, butyl rubber, and ethylene-propylene rubber. and natural rubber.

[0020] The ink layer 14 is a conventionally known heat-melting layer, and contains colorants, waxes, and resins as main components.

The coloring agent is appropriately selected from conventionally known dyes and pigments.

Examples of waxes include paraffin wax, microcrystalline wax, oxidized paraffin wax, candelilla wax, carnauba wax, montan wax, ceresin wax, polyethylene wax, oxidized polyethylene wax, castor wax, hardened tallow oil, and lanolin. , wood wax, sorbitan stearate, sorbitan palmitate, stearyl alcohol, polyamide wax, oleylamide, stearylamide, hydroxystearic acid, synthetic ester wax, synthetic alloy wax and the like.

Examples of resins include polyamide-based, polyester-based, polyurethane-based, vinyl chloride-based, cellulose-based, petroleum-based, styrene-based, butyral-based, and phenol-based resins, as well as ethylene-vinyl acetate copolymers and ethylene. - Examples include acrylic resins.

The ratio of each material constituting the ink layer 14 is colorant/wax/resin=5 to 50/3.
0-90/5-50 is appropriate.

In addition to these, known plasticizers and oils such as fatty acid esters, glycol esters, phosphoric acid esters, and epoxidized linseed oil may be added to the ink layer 14 in small amounts (30% or less). do not have.

The ink layer 14 can be formed by applying a hot melt or dissolving or dispersing the ink in a solvent and drying it. Thickness is 1-10μm, preferably 1.5-3μm
It is μm. When the thickness of the ink layer 14 is thinner than 1 μm,
Printing may be missing due to insufficient density or paper with relatively low smoothness.
On the other hand, if the thickness exceeds 10 μm, the adhesive strength decreases, causing the ink layer 14 to peel off at low temperatures, and as the thickness of the ink layer 14 increases, the shear strength increases, which may lead to poor transfer. .

In another thermal transfer recording medium of the present invention, all or part of the pigment contained in the matte layer is made of silica particles whose surface is treated with a silicone resin having a particle size of 0.1 to 2.0 μm. That is. As a method for surface-treating these silica particles with silicone, for example,
% carbon tetrachloride solution, air-dried, and then baked at 300° C. for about 5 minutes.

By using such a material as a component of the matte layer, the gloss of the printed image is further reduced, and the reading of the barmade is more accurate.

[Example] Next, Examples and Comparative Examples will be shown. Parts here are by weight.

Example 1 Polyethylene terephthalate (PE) with a thickness of about 4.5 μm
T) On the film, mix and disperse the following component A using a Dyno Mill and apply a coating solution containing silicone surface-treated silica with an average particle size of about 1.5 μm using a wire bar so that the thickness after drying is about 1.0 μm. A matte layer was formed by drying. (Component A) Silicone surface treated silica

3 parts (Mizukasil P-832: processed by Mizusawa Chemical Co., Ltd.) Polyester resin

7 parts Methyl ethyl ketone

45 parts toluene

45 copies

003
0 A coating liquid of component B below was applied onto the above matte layer using a wire bar to a dry thickness of about 1.5 μm, and dried to form a release layer. (Ingredient B) Carnauba wax

Part 73 Candelilla wax

15 parts Polybutadiene rubber (manufactured by Japan Synthetic Rubber Co., Ltd.: JSR BR 3
1) 12 parts toluene

900 copies

[0031] Furthermore, a coating liquid consisting of component C below was applied using a wire bar to a dry thickness of about 2 μm, and dried to form an ink layer, thereby producing a thermal transfer recording medium. . (Component C) Carnauba wax water dispersion (solid content 30%)
183 parts Candelilla wax aqueous dispersion (solid content 30%)
67 parts Ethylene-vinyl acetate copolymer aqueous dispersion (solid content 30%)
33 parts carbon black water dispersion (solid content 20%)
75 parts surfactant (Rheodol
TW-S120)
Part 1 Water


61 parts methanol

80 copies

[0032]
Example 2 A thermal transfer recording medium was produced in exactly the same manner as in Example 1 except that the B component was replaced with the D component below. (Ingredient D) Carnauba wax

70 parts paraffin wax (manufactured by Nihon Seiro Co., Ltd.: HNP-16)
19 parts Polybutadiene rubber (manufactured by Japan Synthetic Rubber Co., Ltd.:
JSR BR31) 8 parts Styrene-butadiene rubber (manufactured by Japan Synthetic Rubber Co., Ltd.: JSR
1712) 3 parts Toluene

900
Department

Example 3 A thermal transfer recording medium was produced in exactly the same manner as in Example 1 except that the component B was replaced with the component E below. (E ingredient) Carnauba wax

70 parts Montan wax (manufactured by Hoechst: Hoechst-Wax KP) 17 parts
Polybutadiene rubber (manufactured by Nippon Zeon Co., Ltd.: Nipol)
BR1220) 5 parts Acrylonitrile-
butadiene rubber
5 parts (manufactured by Japan Synthetic Rubber Co., Ltd.: JSR N234L) Polystyrene resin (manufactured by Esso Standard Oil Co., Ltd.: D125)
Part 3 Toluene

900 copies

[
Comparative Example 1 A thermal transfer recording medium was produced in exactly the same manner as in Example 1 except that the B component was replaced with the F component below. (F ingredient) Carnauba wax

Part 75 Cadilla wax

15 parts ethylene-vinyl acetate copolymer
10 parts (EVA manufactured by DuPont Mitsui Polychemicals)
FLEX 210) Toluene

900
Department

Comparative Example 2 A thermal transfer recording medium was produced in exactly the same manner as in Example 1 except that the B component was replaced with the G component below. (G ingredient) Carnauba wax

Part 55 Candelilla wax

20 parts polybutadiene wax (manufactured by Japan Synthetic Rubber Co., Ltd.: JSR BR
31) 15 parts Styrene-butadiene rubber (manufactured by Japan Synthetic Rubber Co., Ltd.: JSR 1712) 10 parts
toluene

900 copies

Regarding these five types of thermal transfer recording media, a thermal transfer printer for barcodes (manufactured by TEC Co., Ltd.: TECB-6) was applied to surface-treated mirror coated paper (manufactured by Kanzaki Paper Co., Ltd.) with a Beck smoothness of approximately 4000 seconds.
5), printing was performed under the conditions of 5° C. and 30% RH, applying standard energy (15.2 mj/mm 2 ). The results are shown in Table 1.

[0037]

[Table 1] (The adhesion force of the mat layer to the support is 100gf/c
m)

(Note 1) Method for measuring adhesive force of shear force: Figure 2
Ni Tensilon (Tensile/compression testing machine: Minebea: TC
M-200CR) to measure the combined shear force and adhesive force of the release layer and ink layer. 2 in the diagram is adhesive tape (manufactured by Ichiban Co., Ltd.: Cellotape 18mm x 35mm)
The adhesive surface faces the thermal transfer recording medium 1. Measurement conditions were a peeling angle of 180° and a peeling speed of 50 mm.
/min, the width of the test piece was 10 mm, and the measurement was performed at an environmental temperature of 5°C. Here, "shear strength" refers to the force applied when peeling begins, with only the release layer and ink layer remaining on the adhesive tape side, and "adhesive strength" refers to the force applied during peeling. It means. In addition, in the figure, 3 is a reinforcing plate made of stainless steel, and 4 is a fixture. (Note 2) Transferability: Evaluation was made based on whether the barcode part was clearly printed. ○: The barcode part is clearly printed and transferred. ×: The barcode portion is printed unclearly, and some barcodes are not partially transferred. (Note 3) Reading rate of barcode part: Laser check the barcode part with LC-2811 (S
ymbol Technologies. Inc. The number of times the laser was scanned 100 times and the number of readings was expressed as a percentage. That is,
100% reading rate is achieved by scanning the laser 100 times.
This indicates that the barcode has been successfully read 0 times, indicating that the barcode is clear.

Example 4 A thermal transfer recording medium was prepared in exactly the same manner as in Example 1, except that the above component A was replaced with the following component D. (Component D) Silicone surface treated silica

5 parts (Silton AK: processed by Mizusawa Chemical Co., Ltd.)
Average particle size: approx. 0.8 μm) Vinyl chloride-vinyl acetate copolymer
5 parts Methyl ethyl ketone

90 copies of this thermal transfer recording medium was prepared under the same test conditions as in Example 1 (with the exception of 20 copies).
When printing was carried out under the conditions of 60% RH and 60% RH, results comparable to those of the thermal transfer recording medium of Example 1 were obtained. Moreover, the glossiness of this product was measured to be 10.0%.

[0040]

According to the first thermal transfer recording medium of the present invention, the combined shear strength of the release layer and ink layer is 30 to 70 gf/cm at 5°C, and the adhesive strength to the matte layer is 1.
．． 5 to 5.0 gf/cm, and by combining the matte layer so that its adhesive strength to the support is greater than that of the release layer and ink layer combined, the ink layer will not peel off in a low-temperature environment. Clear ladder barcodes can be printed, the abrasion resistance of the transfer surface after printing is improved, and matte printing is possible. According to the second thermal transfer recording medium of the present invention, the abrasion resistance of the transfer surface after printing is improved, and the gloss of the printed image is significantly reduced, making it possible to read barcodes accurately.

[Brief explanation of drawings]

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

Figure 2: Tensile and
This is an outline of the compression tester.

[Explanation of symbols]

1 Thermal transfer recording medium 11 Film-like support 12 Matte layer 13 Peeling layer 14 Ink layer 15 Heat-resistant protective layer

Claims (4)

[Claims] Claim 1: A matte layer containing a pigment and a resin as the main components is provided on a support, a release layer containing a wax as the main components is provided on top of the matte layer, and further a coloring agent, a wax and a resin are provided as the main components on top of the matte layer. In a thermal transfer recording medium provided with an ink layer, the combined shear strength of the release layer and ink layer is 30 to 70 gf/cm at 5°C, and the adhesive strength to the matte layer is 1.5 at 5°C. A thermal transfer recording medium characterized in that it has a particle diameter of 5.0 gf/cm. 2. The thermal transfer recording medium according to claim 1, wherein the adhesive strength of the matte layer to the support is greater than the adhesive strength to the matte layer including the release layer and the ink layer. [Claim 3] The thickness of the mat layer is 0.2 to 3 μm.
The thermal transfer recording medium according to claim 1. 4. A matte layer containing pigment and resin as main components is provided on a support, a release layer containing wax as main components is provided on top of the matte layer, and further a coloring agent, wax and resin are provided as main components on top of this. In a thermal transfer recording medium provided with an ink layer, some or all of the pigments in the matte layer have a particle size of 0.1 to 2.
．． A thermal transfer recording medium characterized in that it is made of silica powder whose surface is treated with a 0 μm silicone resin.