JP2571851B2 - Thermal transfer material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial application field) The present invention relates to a color heat-sensitive transfer material having a layer containing a near-infrared absorber that selectively absorbs specific near-infrared rays.
The present invention relates to a heat-sensitive transfer material which is easy to visually recognize and has a beautiful appearance and gives a high-quality bar code or the like.

(Prior art) Conventionally, barcodes are assigned to products in order to streamline product management in factory automation, POS, and distribution, but most of the color materials other than black are in the detection wavelength range of the barcode reader. Does not have sufficient absorption to limit the range of color choices. For this reason, it is not possible to arbitrarily add a color tone barcode in accordance with the product image, which impairs the beauty of the product. Also, it is very difficult even for humans to easily identify products easily.

JP-A-64-30788 proposes a method of adding a near-infrared absorbing agent other than carbon black to a hot-melt ink layer. However, there is a disadvantage that the effect of the above is not sufficiently exhibited. In addition, the transfer surface obtained by thermal transfer recording using only a base film having a hot-melt ink layer provided thereon is peeled off at the interface between the smooth base film and the hot-melt ink. High smoothness and glossy surface. However, a glossy surface is generally difficult to read depending on the angle, and a matte printing surface is desired.

(Problems to be Solved by the Invention) The present inventors have conducted intensive studies on a method of producing a barcode other than black, and as a result, have found that the thermal transfer material for color barcodes has excellent aesthetics and light resistance and facilitates visual identification. Is provided.

[Configuration of the invention]

(Means for Solving the Problems) That is, the present invention provides a substrate comprising a layer which causes cohesive failure during thermal transfer, a heat-meltable ink layer containing a near infrared absorbing agent other than carbon black, and a coloring agent other than carbon black. The present invention relates to a heat-sensitive transfer material for color barcodes, which is provided with a heat-meltable colored ink layer in order.

Since the heat-sensitive transfer material of the present invention can use any color material for the heat-meltable colored ink layer, it is easy to visually identify when recording with a thermal head using the heat-sensitive transfer material of the present invention. At the same time, it is possible to obtain a beautiful and high-quality color barcode recorded matter that matches the image of the product. The barcode recorded material can be read by a normal barcode reader that absorbs and detects near-infrared rays, and is effective for collation of manufacturing lot numbers and product numbers assigned to various products for product management.

The coloring materials that can be used for the hot-melt colored ink layer are red,
Green, blue, yellow, red, indigo dyes / pigments, pastel / white / pearl pigments, fluorescent dyes, gold / silver metal powders, etc., are not particularly limited.

The near-infrared ray of the present invention generally refers to an electromagnetic wave in the range of 690 to 2500 nm, but in the present invention, it is preferable to use near-infrared rays having a main wavelength of 690 to 1000 nm.

Known near-infrared absorbers according to the present invention
It absorbs electromagnetic waves in the range of 690 to 1000 nm, and includes, for example, compounds of the chemical structural formulas shown in Table 1, dithiol metal complex salts, anthraquinones, mercaptonnaphthol metal complex salts, naphthoquinones, cyanine dyes, and the like.

However, it is preferable to use one or two or more kinds of near-infrared absorbing agents because near-infrared absorbing agents having different wavelengths are used depending on the application.

When a recording material made of a thermal transfer material containing a near-infrared absorbing agent is exposed to sunlight, it deteriorates due to the effect of ultraviolet rays, and a sufficient effect cannot be obtained. In order to prevent these, a layer containing an ultraviolet absorber can be provided between a layer causing cohesive failure during thermal transfer and a layer containing a near-infrared absorber. The ultraviolet absorber of the present invention has a function of absorbing harmful ultraviolet light of 290 to 400 nm, and examples thereof include the compounds shown in Table 2.

The layer that causes cohesive failure during thermal transfer causes cohesive failure when transferring and peeling the hot-melt ink layer, and the unevenness of the destruction surface gives a matte effect to the barcode recorded material, making it easy to read with a barcode reader. I do. The layer that causes cohesive failure usually does not contain a coloring agent. Examples of the compound contained in the cohesive failure layer include a higher fatty acid amide or a derivative thereof. The cohesive failure layer is disclosed in the specification of Japanese Patent Application No. 62-60215.

In order to provide the near-infrared absorbing layer, hot-melt colored ink layer, ultraviolet absorbing layer and cohesive failure layer of the present invention on a substrate, a hot melt coating method or more preferably a coating method in which the above compound is dispersed in a medium is used. There is a method of solvent-coating the liquid. Coating amount: 0.1μm to 3μm
Is appropriate. If it is less than 0.1 μm, the effect of each layer is reduced, and if it is more than 3 μm, the total coating thickness becomes large, and when the transfer material is wound into a roll, the winding becomes thick and the energy sensitivity decreases.

A conventionally known base film can be used for the support of the present invention. For example, there are polyester films (polyethylene terephthalate, polyethylene naphthalate, etc.), polyamide films (nylon, etc.), polyolefin films (polypropylene, etc.), cellulose films (triacetate, etc.), polycarbonate films and the like. The polyester film is most preferable because of its excellent heat resistance, mechanical strength, tensile strength, tensile stability and the like. The thinner this substrate is, the better the thermal conductivity is, but the thickness is most preferably 3 to 50 μm from the viewpoint of strength and ease of coating the ink layer. Further, a back coat layer made of a heat-resistant resin may be provided on the surface of the substrate opposite to the heat-meltable ink layer.

In the hot-melt ink layer of the present invention, a conventionally known composition component can be used as it is. Examples thereof include those colored with the above-mentioned dyes and pigments using wax and thermoplastic resin as binders. Examples of waxes include candelilla wax, carnauba wax, rice wax, vegetable waxes such as wood wax and jojoba oil, animal waxes such as beeswax, lanolin, and spermaceti, petroleum waxes such as montan wax and petrolatum, and synthetic waxes. Synthetic hydrocarbons such as fusher tropic wax and polyethylene wax, modified waxes such as montan wax derivatives, hydrogenated waxes such as hardened castor oil and hardened castor oil derivatives, lauric acid, palmitic acid, myristic acid, stearic acid, 12-hydroxystearin Examples of fatty acids such as acids, waxes such as fatty acid amides, fatty acid anilides and imido wax, and resins include:
Acrylic, styrene, rosin, vinyl, acetal, and rubber are preferred.

If necessary, a small amount of additives such as a plasticizer, a dispersant, an activator, an antistatic agent, and a stabilizer can be added to the hot-melt ink.

Hereinafter, the present invention will be described in detail with reference to examples. All parts in the examples represent "parts by weight".

Example 1 A coating liquid having the following composition was dispersed and mixed at room temperature using an attritor to obtain an ink for forming a cohesive failure layer. The obtained ink was applied on a 6 μm polyethylene terephthalate film by a gravure coating method to a coating thickness of 1 μm.

Lithium stearate (melting point: 216 ° C) 1 part Carnauba wax 19 parts Evaflex 420 1 part Toluene 79 parts Then, a coating liquid having the following composition is sufficiently dispersed at room temperature with an attritor to obtain an ultraviolet absorbing ink. The resulting ink was applied on the cohesive failure layer to a coating thickness of 1 μm by a gravure coating method.

Ethylene-vinyl acetate copolymer 1 part Carnauba wax 19 parts UV absorber ("TINUVIN 90" manufactured by Nippon Ciba Geigy Co., Ltd.)
0 ") 0.5 parts Toluene 50 parts Methyl isobutyl ketone 29.5 parts Further, a coating liquid having the following composition was sufficiently dispersed at room temperature with an attritor to obtain a near-infrared absorbing ink, and the obtained ink was placed on the ultraviolet absorbing layer. Coating thickness 1.6 by gravure coating method
μm.

Ethylene-vinyl acetate copolymer (Evaflex manufactured by Mitsui Polychemicals Co., Ltd.) 1 part Carnauba wax (Noda Wax Co., Ltd.) 19 parts Near infrared absorber (ICI "SC101756") 0.2 parts Toluene 50 parts 29.5 parts of methyl isobutyl ketone 60% glass beads with an average particle size of 0.5 mm
The following composition pre-mixed in a filled 5 liter sand mill was charged at a rate of 2 liters / minute by a gear pump, and the sand mill was rotated at a speed of 10 m / s to perform kneading.
Repeat the process to obtain a hot-melt ink, and apply the obtained ink on the near-infrared absorbing layer by a gravure coating method to a thickness of 5 μm.
To obtain a heat-sensitive transfer material.

Rice wax (“LP-200” manufactured by Noda Wax Co., Ltd.) 20 parts Aqueous acrylic resin (“Riocryl AP-2” manufactured by Toyo Ink Mfg. Co., Ltd., solid content 27%) 8 parts Water 40 parts Ethanol 29 parts CI Direct Red 2 ("Nippon Kayaku Co., Ltd."
4B ”) 3 copies When the barcode was printed with a barcode label printer using the obtained thermal transfer material, a matte barcode print was obtained, which could be read by a barcode reader with a reading wavelength of 780 nm. there were.

Comparative Example 1 The hot-melt ink layer of Example 1 was applied to a 6 μm polyethylene terephthalate film with a coating thickness of 5 μm by a gravure coating method. When evaluated in the same manner as in Example 1, no reading was performed, and the reflectance at 780 nm was 97%.

Comparative Example 2 The hot-melt ink layer of Example 3 was coated with
It was applied to a coating thickness of 5 μm on a polyethylene terephthalate film of μm. When evaluated by the same method as in Example 1, it could not be read by a barcode reader having a reading wavelength of 780 nm, and the reflectance at 780 nm was 98%.

(Function and Effect of the Invention) A major feature of the present invention is that any color material can be used for the hot-melt colored ink layer, and thus a color barcode of any color other than black can be obtained. When the thermal transfer material of the present invention is used, it is possible to facilitate visual identification and obtain a beautiful and high-quality color barcode recorded matter that matches the image of the product.

Another major feature of the present invention is that it has a layer that causes cohesive failure at the time of thermal transfer, has a matting effect, and is capable of obtaining a barcode record which is easy to read by a barcode reader. .

Further, another feature of the present invention is that by providing a layer containing an ultraviolet absorber between the layer that causes cohesive failure at the time of thermal transfer and the near infrared absorption layer, deterioration of the near infrared absorber by ultraviolet light can be suppressed. On the point.

Claims (4)

(57) [Claims] A layer which causes cohesive failure during thermal transfer on a substrate;
A heat-sensitive transfer material for color barcodes, comprising a heat-meltable ink layer containing a near-infrared absorbing agent other than carbon black and a heat-meltable colored ink layer containing a colorant other than carbon black. 2. The heat-sensitive transfer material for color barcodes according to claim 1, wherein said near-infrared absorbing agent has an absorption maximum wavelength at 690 to 1000 nm. 3. A layer containing an ultraviolet absorber is provided between a layer which causes cohesive failure during thermal transfer and a heat-meltable ink layer containing a near infrared absorber. Thermal transfer material for color barcodes. 4. The heat-sensitive transfer material for color barcodes according to claim 1, wherein a heat-resistant protective layer is formed on the surface of the base material opposite to the heat-meltable ink layer.