JP2579685B2 - Thermal transfer material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial application field) The present invention provides a light-resistant, almost light-resistant, It relates to a colorless or color thermal transfer material. More specifically, thermal transfer recording using a thermal transfer material having a layer containing a near-infrared absorbing agent, which suppresses the near-infrared absorbing effect due to ultraviolet light, has excellent light resistance and is suitable for product images or stands out. The present invention relates to a thermal transfer material which gives no 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 aesthetic appearance of the product.

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, in the case of a bar code, the light resistance is poor, and it is sufficient when exposed to sunlight. No significant absorption effect. Also,
When simply mixed with a colorant having a high hiding property, there is a disadvantage that the effect of near-infrared absorption 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) As a result of intensive studies on a method of producing a bar code other than black, the present inventors have found that a colorless or color bar code having excellent light resistance and aesthetic appearance, and which does not impair the product image. And the like.

[Configuration of the invention]

(Means for Solving the Problems) That is, the present invention relates to a base material, a layer which causes cohesive failure during thermal transfer, a hot-melt ink layer containing an ultraviolet absorbent, and
The present invention relates to a thermal transfer material for barcodes other than black, which is provided with a heat-meltable ink layer containing a near-infrared absorbing agent other than carbon black having an absorption maximum wavelength in the range of 690 to 1000 nm.

Since the heat-sensitive transfer material of the present invention has a layer containing an ultraviolet absorbent, when recorded by a thermal head using the heat-sensitive transfer material of the present invention, the heat-sensitive transfer material is excellent in light resistance and almost matches the image of the product. Colorless or colored bar code recordings other than black can be obtained. The above barcode record is
It can be read by a normal bar code reader that absorbs and detects near infrared rays, and is effective for collation of manufacturing lot numbers and product numbers given for product management of various products.

The ultraviolet absorbent of the present invention has a function of absorbing harmful ultraviolet light having a wavelength of 290 to 400 nm, and examples thereof include the compounds shown in Table 1. By providing the above-mentioned layer containing the ultraviolet absorber between the layer causing cohesive failure during thermal transfer and the layer containing the near-infrared absorber and taking measures against ultraviolet rays, deterioration of the near-infrared absorber in the recorded matter is prevented, and , A decrease in the near-infrared absorption effect due to the above. The effect may be further enhanced by using an antioxidant in the ultraviolet absorbing layer.

On the layer containing the near-infrared absorbing agent, a hot-melt colored ink layer containing an arbitrary coloring material other than carbon black can be provided for coloring. Coloring materials that can be used in the coloring layer include red, green, blue, yellow, red, indigo dyes / pigments, pastel / white / pearl pigments, fluorescent dyes, and gold / silver metal powders. There is no restriction.

In some cases, a coloring agent other than carbon black may be added to the layer containing the near-infrared absorbing agent. In this case, however, it is desirable to use a coloring material having a low concealing property in the near-infrared wavelength region. For example, when a coloring material having a high concealing property in a near infrared wavelength region such as a metal powder is used, it is better to separate layers of the near infrared absorbing agent and the coloring material.

The near-infrared absorbing agent of the present invention generally absorbs an electromagnetic wave in the range of 690 to 1000 nm. Dyes and the like can be mentioned.

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.

The layer that causes cohesive failure during thermal transfer causes cohesive failure when transferring and peeling off the hot-melt ink layer, and its uneven surface gives the matte effect to the barcode record, 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 Japanese Patent Application No. 62-60215.

In order to provide the ultraviolet-absorbing layer, near-infrared-absorbing layer, coloring layer and cohesive failure layer of the present invention on a substrate, a hot melt coating method or, more preferably, solvent coating of a coating liquid in which the above compound is dispersed in a medium. There is a way. The coating thickness of the ultraviolet absorbing layer, the near infrared absorbing layer and the cohesive failure layer is suitably 0.1 μm to 2 μm, respectively. The coating thickness of the colored layer is suitably 0.5 to 10 μm.
If the coating thickness is too thin, the effect of each layer will be reduced, and if it is too thick, the total coating thickness will be large, and when the transfer material is rolled, the winding will be thickened and the energy sensitivity will be reduced.

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, the components used in conventionally known compositions can be used as they are. Examples of such components include waxes and thermoplastic resins, which are colored with the above-described dyes and pigments 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
Fatty acids such as hydroxystearic acid, and waxes such as fatty acid amides, fatty acid anilides and imido wax;
As the resin, acrylic, styrene, rosin, vinyl, acetal, and rubber are preferable.

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 (manufactured by Mitsui Polychemicals Co., Ltd.) Toluene 79 parts Then, a coating solution having the following composition was sufficiently dispersed at room temperature with an attritor, and The obtained ultraviolet absorbing ink was applied to a thickness of 1 μm on the cohesive failure layer by a gravure coating method.

Ethylene-vinyl acetate copolymer 1 part (Mitsui Polychemical Co., Ltd. "Evaflex 577-
2)) Carnauba wax ("Carnauba wax No.1" manufactured by Noda Wax Co., Ltd.) 19 parts Benzotriazole ("TINU" manufactured by Nippon Ciba Geigy Co., Ltd.)
VIN 900 ”) 0.5 parts Antioxidant (IRGANOX 101 manufactured by Ciba-Geigy Japan, Ltd.)
0 ”) 0.1 part Toluene 50 parts Methyl isobutyl ketone 29.4 parts Further, a coating liquid having the following composition was sufficiently dispersed at room temperature using an attritor, and the obtained near-infrared absorbing ink was coated on the ultraviolet absorbing layer by a gravure coating method. Was applied to a coating thickness of 1.6 μm.

Ethylene-vinyl acetate copolymer 1 part (Mitsui Polychemical Co., Ltd. "Evaflex 577-
2)) Carnauba wax 19 parts Near infrared absorber 0.2 parts (IC-Japan "PRO-JET IR SC101756") Toluene 50 parts Methyl isobutyl ketone 29.8 parts In addition, glass beads with an average particle diameter of 0.5 mm are 60 in volume. %
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.
This was repeated twice, and the resulting hot-melt ink was applied on the near-infrared absorbing layer to a coating thickness of 5 μm by a gravure coating method to obtain a thermal transfer material.

Rice wax (“LP-200” manufactured by Noda Wax Co., Ltd.) 20
Part Water-based acrylic resin 8 parts (Toyo Ink Manufacturing Co., Ltd. “Riocryl AP-2”, solid content
27%) Water 40 parts Ethanol 29 parts CI Direct Red 2 3 parts (Nippon Kayaku Co., Ltd. "Kayaras benzoperbulin 4B") Using the obtained thermal transfer material, Beck smoothness with a bar code label printer When a barcode was printed on the recording paper for 100 seconds, a matte barcode record having excellent light resistance was obtained, and the barcode reader having a reading wavelength of 780 nm could read the barcode. After exposing the recorded matter to sunlight for three days in fine weather, a spectrophotometer (Shimadzu Corporation)
When the reflectance at 780 nm was measured using “UV-365”), the decrease in the absorptance was about 8%.

Comparative Example 1 The near-infrared absorbing ink of Example 1 was applied to a 6 μm polyethylene terephthalate film by a gravure coating method to a coating thickness of 5 μm. When evaluated by the same method as in Example 1, the image was read with a bar code reader having a reading wavelength of 780 nm. However, the light resistance was poor and the absorption rate at 780 nm was reduced by about 37%.

Comparative Example 2 The near-infrared absorbing layer and the hot-melt ink layer of Example 1 were coated on a 6 μm polyethylene terephthalate film by a gravure coating method to a thickness of 1.6 μm and 5 μm, respectively.
Was sequentially applied. When evaluated by the same method as in Example 1, the light was read by a bar code reader having a reading wavelength of 780 nm, but the light resistance was poor and the decrease in the absorptance at 780 nm was about 3%.
0% was observed.

(Functions and Effects of the Invention) A major feature of the present invention is that by providing a layer containing an ultraviolet absorbent and taking measures against ultraviolet rays, a bar code which does not deteriorate even when exposed to sunlight and has excellent light resistance can be obtained. On the point. By using the thermal transfer material of the present invention, it is possible to obtain a barcode record excellent in light resistance, which can be read by a barcode reader that absorbs and detects near infrared rays.

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 a layer containing a near-infrared absorbing agent contains a coloring agent other than carbon black, so that a bar code recording of a beautiful and high-grade color suitable for an image of a product in an arbitrary color tone. The point is that you can get things.

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-63-159087 (JP, A) JP-A-64-30788 (JP, A) JP-A-61-57392 (JP, A) JP-A-60-1985 85990 (JP, A) JP-A-64-1585 (JP, A) JP-A-63-60794 (JP, A) JP-A-59-224392 (JP, A)

Claims (3)

(57) [Claims] A layer which causes cohesive failure during thermal transfer on a substrate;
Hot melt ink layer containing UV absorber and 690-1000n
A heat-sensitive transfer material for barcodes other than black, characterized in that a heat-meltable ink layer containing a near infrared absorbing agent other than carbon black having a maximum absorption wavelength at m is sequentially provided. 2. The heat-sensitive transfer material for barcodes other than black according to claim 1, wherein the layer containing the near-infrared absorbing agent further contains a coloring agent other than carbon black. 3. The heat-sensitive transfer material for barcodes other than black according to claim 1, wherein a heat-resistant protective layer is formed on the surface of the substrate opposite to the heat-meltable ink layer.