JPH0116116Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a heat-sensitive coloring label.

Conventional heat-sensitive color-forming labels use water-soluble materials that have a color-forming function, so they do not have weather resistance against moisture, etc. Moreover, they develop color when heated, so they do not have a color-forming function at the time of manufacture. After applying the material, it is dried without much heating, which takes time to dry and also reduces weather resistance.
In order to ensure water resistance, etc., a solvent-based material may be used as a material having a color-forming function, but in that case, the solvent has the property of degrading the color-forming agent itself and cannot be used. Therefore, it has poor chemical resistance and solvent resistance, and is not suitable for use in places where chemical or solvent resistance is required, and is not suitable as a label to be used under harsh conditions, and its uses are limited. This has become a major obstacle to practical application.

The present invention was developed in view of the above circumstances, and eliminates the various drawbacks of conventional labels.Drying of the heat-sensitive coloring material is easy during production, increasing label production efficiency, and making it easy to use in frozen cases, etc. It can also be used as a label to be used under such harsh conditions, and it does not inadvertently develop color after or before coloring, and does not prevent the heat-sensitive coloring material from getting wet or damp even during use. It is an object of the present invention to provide a heat-sensitive color-forming label that prevents deterioration of the heat-sensitive color-forming material by reducing the chances of chemicals etc. coming into contact with the heat-sensitive color-forming material.

Hereinafter, the present invention will be specifically explained based on the drawings.

Reference numeral 1 denotes a label base material made of paper, synthetic paper, synthetic resin sheet, film, metal foil, etc., or a composite sheet made by laminating these materials.

2 is a thermosensitive coloring layer that develops color when heated.
The heat-sensitive coloring layer 2 includes a dye 3 which is colorless or light-colored at room temperature, such as solid particles such as leuco, lactone, and lactam.
A heat-sensitive element 4 made of an acidic substance or the like that causes the dye 3 to develop color is used as a core material, and the core material is encapsulated with a film-forming material 5 such as a heat-softening resin to form microcapsules, and the core material is encapsulated in a binder. The labels are dispersed and isolated and applied to the surface of the label base material 1. When heat is applied, the wall material surrounding the microencapsulated core material is dissolved, and the dye 3 and the heat-sensitive element 4 come into contact to cause a chemical reaction, resulting in color development.

However, as the thermosensitive coloring layer 2, an opaque porous layer is laminated on the surface of the label base material 1, and when heated, the thermosensitive coloring layer 2 dissolves and fine particles on the surface of the porous layer are formed. The label base material 1 may be of such a type that the unevenness and voids disappear, the label base material 1 becomes transparent, and the color of the label base material 1 is developed. The heat-sensitive coloring layer 2 is formed by melting the wall material made of the film-forming material 5 and causing a chemical reaction when the dye 3 and the heat-sensitive element 4 come into contact, and by melting the opaque porous layer. If the temperature at which the minute irregularities and voids on the surface of the porous layer disappear and the layer becomes transparent is set to a different temperature condition, the porous layer will be exposed to the area where the dye 3 and the heat-sensitive element 4 come into contact and cause a chemical reaction at a predetermined temperature. The thermosensitive color forming layer 2, which has the color of the label base material 1, for example, is distinguished from the part where fine irregularities and voids on the surface of the color layer disappear and become transparent.
By using a color that is different from the color of the label, it is possible to create a label that shows a different type of color.

6 is a protective layer formed by curing an ultraviolet curable material laminated on the surface of the thermosensitive coloring layer 2 by irradiating ultraviolet rays. UV-curable materials include polyester resins, acrylates, etc.
It consists of a prepolymer such as methacrylates, a photoinitiator, a reactive diluent, etc., and is printed using printing methods such as gravure printing, offset printing, and screen printing.
A protective layer is formed by coating the UV curable material. The ultraviolet curable material coated on the surface of the thermosensitive coloring layer 2 is cured by irradiating it with ultraviolet rays using a commercially available ultraviolet curing device.

7 is an adhesive layer formed on the back surface of the label base material 1, and is coated with a pressure-sensitive adhesive or the like.

8 is a release sheet to which the label base material 1 is temporarily attached in order to protect the adhesive layer 7 and support a plurality of label base materials 1 in succession.

Note that this label does not have a predetermined label shape as shown in FIG. 2, but a band-shaped label base material 1 is initially laminated on a release sheet 8, and a punching die A having a predetermined blade is used to cut the label base material 1. It may be formed by punching out the release sheet 8 to the extent that it reaches the surface but does not damage it, and then peeling off unnecessary parts from the release sheet 8.

Then, as shown in FIG. 3, for example, this label is rolled up into a roll and mounted on a label printing and pasting machine, and a thermal head B is brought into contact with the surface of the label to color the thermosensitive coloring layer 2. It is a good idea to print characters, barcode symbols, etc. and use them.

The present invention is constructed as described above, and a protective layer made of an ultraviolet curable material cured by ultraviolet irradiation is provided on the surface of the thermosensitive coloring layer, so that the thermosensitive coloring layer is protected by the protective layer, and the protective layer If UV-curable resin is used as a UV-curable resin, it will be chemically stable and will not affect the coloring agent, making it water resistant and
It is possible to obtain labels with excellent weather resistance, chemical resistance, and solvent resistance, which can improve productivity. It can be used as a label that is exposed to harsh conditions, and its range of use is extremely wide as barcode labels and the like.

In addition, since the UV-curable material is cured by UV irradiation, it does not require time to dry during manufacturing, unlike when using water-soluble materials, and drying after application is done using UV rays instead of heat. Because of this, there is no need to worry about the coloring agent developing color during drying, and it also has excellent workability because it hardens extremely instantaneously.

[Brief explanation of the drawing]

Fig. 1 is a sectional view schematically showing a label that is an embodiment of the present invention, Fig. 2 is a sectional view showing an example of its manufacturing method, and Fig. 3 is an explanatory diagram showing its usage. be. 1...Label base material, 2...Thermosensitive coloring layer, 6...
Protective layer, 7... Adhesive layer, 8... Release sheet.

Claims (1)

[Claims for Utility Model Registration] A label base material, and a heat-sensitive element as a core material on the surface of the label base material, and a film-forming material encapsulated around the core material to form microcapsules. A label comprising: a heat-sensitive coloring layer coated with a heat-sensitive coloring agent; and a protective layer formed by curing an ultraviolet curable material on the surface of the heat-sensitive coloring layer by irradiating ultraviolet rays.