JPH06183115A - Thermal transfer sheet and manufacture thereof - Google Patents

Abstract

PURPOSE:To improve film cutting property and abrasion resistance by a method wherein a heat melting ink layer is formed by dispersing wax grain having a predetermined grain diameter and colorant in binder resin on one face of a base film, in a bar code printing mark sheet. CONSTITUTION:A rear face coat layer 3 is formed on one face of a base film 1 such as a stretching polyethylene phthalate film having a thickness of about 4.5mum and a heat melting ink layer 2 is formed on other face. The heat melting ink layer 2 is formed in such a manner that the base film 1 is coated with a nonaqueous liquid of acrylic ester resin containing wax grain having a grain diameter of 0.1-10mum and a colorant dispersed therein, and dried at a temperature below a melting point. For the wax grain, animal and plant waxes are used. By using the wax grain, irregularity is formed on the surface of the ink layer 2, so that film cutting property will be improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal fusion transfer sheet, and more particularly to a thermal transfer sheet for bar code printing and a manufacturing method thereof.

[0002]

2. Description of the Related Art Conventionally, a thermal transfer sheet used for printing an output print of a computer, a word processor or the like by a thermal transfer system is generally one in which a heat-fusible ink layer is provided on one surface of a base film. As the base material film, a plastic film represented by a capacitor paper having a thickness of about 10 to 30 μm, a paraffin paper, and a stretched polyester film having a thickness of about 3 to 20 μm is used. The heat-fusible ink layer dissolves pigments such as carbon black and colorants such as dyes in plant wax, petroleum wax, etc.,
It is provided by applying dispersed ink. As for the printing, like bar codes, the bar width, spacing, and printing accuracy at the image edge are required. Further, in order to ensure reliable reading by a bar code reader, the printed matter is particularly durable and scratch resistant. Need sex.

[0003]

However, the conventional thermal transfer sheet in which the heat-meltable ink layer is a single-wax type has the above-mentioned accuracy required for bar code printing,
In order to satisfy the scratch resistance, a thermal transfer sheet has been reported in which a base film is provided with a heat-meltable ink layer consisting of a scratch-resistant first layer having a low color density and a second layer having a high color density in order. ing. (Japanese Utility Model Laid-Open No. 57-199472) A barcode printed using this thermal transfer sheet has a first layer having excellent scratch resistance and a second layer having a density on the surface after transfer.
Since it is composed of layers, the above-mentioned required characteristics are satisfied, but the sharpness of the edge of the image is slightly lacking, and above all, since the heat-meltable ink layer is formed by two coatings, the size of the processing machine is large. However, there is a problem in production technology that the cost is increased due to increase in cost, manufacturing time, and material loss.

The present invention is to provide a thermal transfer sheet which has the problems of the prior art, that is, good film breakage that increases the sharpness of the image end portion of the heat-meltable ink layer, and high scratch resistance of printed matter. To aim.

[0005]

In order to achieve the above object, the present invention provides a substrate film and one surface of the substrate film having an organic compound having a melting point of 50 to 130 ° C., for example,
Acrylic resin, wax particles in a non-aqueous solution containing at least one of styrene acrylic resin, a hot-melt ink formed by dispersing a colorant is applied to the base film,
The heat-meltable ink layer is formed by drying at a temperature below the melting point of the wax particles.

[0006]

[Function] The hot-melt ink formed on the base film is composed of wax particles, a colorant and an acrylic ester resin,
Composed of a vehicle containing at least one of styrene-acrylic resin, the heat fusible ink layer dried at a melting temperature of the wax or less, because the wax is held in a particulate form, the ink film cutting property is good, The sharpness of the edges of the image is increased and the printed matter has high scratch resistance.

Referring to the drawings, the thermal transfer sheet shown in FIG. 1 has a base film 1 and a base film 1.
It has a heat-fusible ink layer 2 on one side and a back layer 3 on the other side. The thermal head of the thermal transfer printer is in contact with the back layer surface, and thermal energy is applied to a predetermined portion of the hot-melt ink via the base film to melt-transfer the hot-melt ink layer to the transfer target.

The base film used in the present invention is not particularly limited as long as it is the same as the conventionally used material. Specific examples include polyester films, polypropylene films, cellophane, polycarbonate, cellulose triacetate, polyvinyl chloride, polyamide, polyimide, and other plastic films, as well as capacitor paper, paraffin paper and other cellulose products, and composite films thereof. . The thickness of the stretched polyethylene terephthalate film and the condenser paper is preferably about 2 to 25 μm.

The back layer is not particularly limited as long as it is the same as the conventionally used material. Its purpose is to improve the slippage of the thermal head and prevent sticking, and has slippage during heating, that is, heat-resistant slippage. It is common to have a heat-resistant resin and a substance acting as a heat release agent or a lubricant as basic constituent components, which makes it possible to use a plastic film relatively weak against heat as a base film. Becomes

The hot-melt ink comprises a colorant, a vehicle in which a binder resin is dissolved in an organic solvent, wax particles which are difficult to dissolve in the organic solvent, and if necessary, additives such as a surfactant and an anti-adhesive agent. Is added.

The colorant can be appropriately selected from known organic or inorganic pigments or dyes, and has a sufficient concentration such as carbon black or phthalocyanine blue, and light,
Those that do not discolor or fade due to heat or the like are preferable.

The binder resin is a polar solvent such as alcohol, ester or ketone, which has a melting temperature of 50 to 130 ° C. which is the same as or higher than the wax particles used in combination or 20 to 30 ° C. higher than that. Or a resin soluble in a solvent containing a small amount of a hydrocarbon solvent. Compatibility with wax film from linear polyester resin, polyacrylic ester resin, styrene acrylate resin, polyamide resin, polyacrylamide resin, polybutyral resin, polyvinyl chloride / vinyl acetate copolymer resin However, the acrylic ester resin and the styrene acrylic resin are preferable. The acrylic ester resin and the styrene acrylic resin are added in order to impart sufficient scratch resistance to the hot melt ink layer, and are contained in the range of 5 to 30% in the solid content of the hot melt ink. Must be present.

The wax particles may be animal or vegetable waxes or petroleum waxes, and carnauba wax, paraffin wax, microcrystalline wax, rice wax, polyethylene wax, polypropylene wax are used, and especially the melting point is 60 to 90. C. Wax particles are preferred. The wax particles used in the present invention preferably have a maximum particle size of 30 μm or less, and particularly preferably wax particles having a particle size of 0.1 to 10 μm are used. By including these particles in the heat-meltable ink, irregularities due to the shape of these particles are formed on the surface of the heat-meltable ink layer, and the ink film breakage becomes good and sharp image edge formation is possible. Becomes In a thermal transfer sheet coated with a heat-meltable ink containing wax particles containing coarse particles having a particle size of 30 μm or more, the sharpness of the printed bar code edge may be lost, resulting in a reading error with a bar code reader. is there.

The wax particles in the present invention were measured by a photon correlation method by a dynamic light scattering method using a helium-neon laser. Alternatively, the particle size can be obtained by applying a wax dispersion solution on a transparent plastic film and observing the surface with an optical microscope or an electron microscope. And
The wax particles are contained in the hot-melt ink layer in an amount of 50 to 90.
It is preferably contained in the range of% by weight.

In the hot-melt ink of the present invention, a binder resin and a colorant are dispersed and dissolved in a non-aqueous solvent dispersion medium, and then wax particles are added and dispersed. The temperature of this step is preferably as low as possible so as not to swell the wax with a non-aqueous solvent, and in the present invention, this operation could be carried out at a temperature of 30 ° C. or lower without any problem.

The heat-fusible ink thus formed is dried on the surface of the substrate film opposite to the back coat layer to form a dry film.
Wire bar coating was performed so as to have a thickness of 4 μm, and the thermal transfer sheet of the present invention was formed by drying with hot air whose temperature was set so that the temperature of the substrate film did not exceed the melting point of the wax.

[0017]

EXAMPLES The present invention will be described with reference to examples. (Example 1) As a base film, a film having a thickness of 4.5 μm was spread.
Expanded polyethylene terephthalate film 1 (Toray Industries, Inc.)
Coating for the back coat layer on one side
The liquid was applied and dried to form the back coat layer 3. Next formulation
The non-back surface of the above-mentioned base film was prepared by preparing the heat-meltable ink of A.
Wire bar coating on coating layer to 2 in solid content_{g / m}2 of
Coat to the coating amount, dry at 55 ℃, heat melting
The ink layer 2 was formed to form the thermal transfer sheet of the present invention.・ Hot-melt ink composition A Carnauba wax CR-8 (maximum particle size 5 μm) Koyo Chemical Co., Ltd. 15 parts Acrylic resin BR-101 Mitsubishi Rayon Co., Ltd. 2 parts Carbon black Fuji SP black 8556 3 parts Methyl ethyl ketone 80 parts The melting point of carnauba wax CR-8 was 83 ° C.
It

(Example 2) Thickness as a base film
4.5 μm stretched polyethylene terephthalate film
Back coat layer on one side of 1 (Lumirror made by Toray Industries, Inc.)
Coating liquid for coating is applied and dried to form back layer coat 3.
did. Next, a hot-melt ink of Formulation B was prepared, and
Apply a wire bar coat to the non-back coat layer of the film.
2 in shape_{g / m}2 So that the coating amount becomes
Dry to form a heat-meltable ink layer 2, which is the same as Example 1
A thermal transfer sheet of the present invention having different particle diameters of the fibers was constructed.・ Hot-melt ink composition B Carnauba wax CR-4K (maximum particle size_Tenμm) Koyo Chemical Co., Ltd. 15 parts Acrylic resin BR-101 Mitsubishi Rayon Co., Ltd. 2 parts Carbon black Fuji SP black 8556 3 parts Methyl ethyl ketone 80 parts

[0019]

Comparative Example (Comparative Example 1) A substrate film having a thickness of 4.5 μm was spread.
Expanded polyethylene terephthalate film 1 (Toray Industries, Inc.)
Coating for the back coat layer on one side
The liquid was applied and dried to form the back coat layer 3. Next formulation
Non-rear surface of the above base film prepared by preparing a heat-meltable ink of C
2 by wire bar coating on solid layer_{g / m}2 Application amount of
So that it will be coated and dried at 55 ℃,
A layer 2 is formed, which is different from the example 1 in that the particle diameter of the wax is changed.
A bright thermal transfer sheet was constructed.・ Hot-melt ink composition C Carnauba wax CR-4K (maximum particle size₃₀μm) Koyo Chemical Co., Ltd. 15 parts Acrylic resin BR-101 Mitsubishi Rayon Co., Ltd. 2 parts Carbon black Fuji SP black 8556 3 parts Methyl ethyl ketone 80 parts

(Comparative Example 2) Thickness as base film
4.5 μm stretched polyethylene terephthalate film
Back coat layer on one side of 1 (Lumirror made by Toray Industries, Inc.)
The coating liquid was applied and dried to form the back layer 3.
Next, the hot-melt ink of Formula D containing no binder resin.
Prepare a wire on the non-backside coating layer of the above base film
2 by solid content by bar coating_{g / m}2 So that the application amount of
Apply and dry at 55 ℃ to form heat-meltable ink layer 2.
A comparative thermal transfer sheet was constructed.・ Hot-melt ink D Carnauba wax CR-4K (maximum particle size_Tenμm) Koyo Chemical Co., Ltd. 15 parts Carbon black Fuji SP black 8556 3 parts Methyl ethyl ketone 80 parts

Next, each thermal transfer sheet was manufactured by Autonics
Bar code printer BC8MK_IIWith the following printing conditions
The standard pattern of the bar code is printed and its print quality and
Table 1 shows the evaluation results of scratch resistance. (Printing conditions) -Applied energy: 0.2968 mJ /_dot ・ Printing speed: 67.2 mm /_sec. (Printing evaluation standard) Scan the bar code with AUTOSCAN manufactured by RIS. ○: Complete reading △: Partial reading  ×: Unreadable  (Scratch resistance test) Tester: HEIDON-14 manufactured by HEIDON Load: 300 g Moving speed: 600 mm / min. (Scratch resistance evaluation standard) ○: The ground portion is not dirty △: The ground portion is dirty ×: The bar code is scraped off

[0021]

[Table 1]

[0022]

As described above, the present invention provides a base film and a heat resistant slipping layer as a back coat layer on one surface of the base film, and the binder resin of the present invention is provided on the opposite side of the base film. Wax particles having a particle size of 10 μm,
Since it is composed of a heat-meltable ink layer in which a colorant is dispersed, the film breakability (printing quality) is good, and the printed matter has high scratch resistance.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a thermal transfer sheet.

[Explanation of symbols]

 1 Base Film 2 Heat Melt Ink Layer 3 Back Coat Layer

Claims (3)

[Claims] 1. A base film and a hot-melt ink layer in which a binder resin is dispersed on one surface of the base film, wax particles having a particle size of 0.1 to 10 μm, and a colorant. A thermal transfer sheet characterized by being configured. 2. The thermal transfer sheet according to claim 1, wherein the binder is an acrylic ester resin or a styrene acrylic resin. 3. A hot melt ink formed by dispersing wax particles and a colorant in a non-aqueous solution of a binder is applied to a base film and dried at a temperature not higher than the melting point of the wax particles to obtain the hot melt property. The method for producing a thermal transfer sheet according to claim 1, wherein an ink layer is formed.