JPH0239822Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a heat-sensitive recording material such as heat-sensitive recording paper.

Conventional thermal recording paper uses water-soluble materials, so the material with the coloring function is not weather resistant to moisture, etc., and also develops color when heated, so it is necessary to coat the material with the coloring function at the time of manufacture. Since it is dried without much heating after drying, it takes a long time to dry, and in order to ensure weather resistance and water resistance, it is better to use solvent-based materials.
It has the property of degrading the coloring agent itself and cannot be used. Therefore, it has poor chemical resistance and solvent resistance,
Not suitable for use or storage in locations where chemical or solvent resistance is required. For this reason, existing recording paper is currently used only for purposes such as office records that are stored indoors with little environmental change.

Therefore, when such thermosensitive color recording paper is used, for example, as a label, due to the above-mentioned drawbacks, there are severe restrictions on its use, and this is a major obstacle to its practical application.

The present invention has been developed in view of the above circumstances, and has been developed to eliminate these drawbacks and to enable heat-sensitive recording materials to be used in harsh environments such as labels, etc. An object of the present invention is to provide a heat-sensitive coloring material in which the heat-sensitive coloring agent is formed so as not to be contaminated with water or moisture, reducing the chances of chemicals etc. coming into contact with the heat-sensitive coloring layer, and preventing deterioration of the heat-sensitive coloring layer. It is.

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

Reference numeral 1 denotes a support made of paper, synthetic paper, synthetic resin sheet, film, metal foil, etc., or a composite sheet made by laminating them.

2 is a thermosensitive coloring layer formed on the surface of the support 1.

The heat-sensitive coloring layer 2 has a core material consisting of a dye 3 that is colorless or light-colored at room temperature, such as solid particles such as leuco, lactone, or lactam, and a heat-sensitive element 4 made of an acidic substance that causes the dye to develop color. The material is encapsulated with a film-forming substance such as a heat-softening resin, microcapsulated, and dispersed and isolated in a binder, which is then coated on the surface of the support 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 support 1, and when heated, the thermosensitive coloring layer 2 is dissolved.
The fine irregularities and voids on the surface of the porous layer may disappear and become transparent, and the color of the support 1 may be developed.

5 is a protective layer formed by curing an electron beam curing material laminated on the surface of the thermosensitive coloring layer 2 by electron beam irradiation. Electron beam curable materials include electron beam curable polyester resins, prepolymers with ethylenically unsaturated bonds such as acrylates and methacrylates, and reactive diluents, and are suitable for gravure printing, offset printing, screen printing, etc. The protective layer 5 is formed by coating the electron beam curable material by a printing method. The electron beam curable material coated on the surface of the thermosensitive coloring layer 2 may be cured using a commercially available low energy electron accelerator. The amount of electron beam irradiation at this time may be an absorbed dose sufficient to harden the electron beam curable material.

The present invention is configured as described above, and since a protective layer formed by curing an electron beam curing material by electron beam irradiation is provided on the surface of the heat-sensitive recording layer, the heat-sensitive recording layer is protected by the protective layer. If you use electron beam curable resin, it is chemically stable, does not affect the coloring agent, and has excellent water resistance and weather resistance.
In addition, it is possible to obtain a heat-sensitive recording material with excellent chemical and solvent resistance, and it can be used in places where the environment changes drastically or where there is moisture or humidity.
Its range of use will be extremely wide. In addition, since the electron beam curable material is cured by electron beam irradiation, it does not take time to dry during manufacturing, unlike when water-soluble materials are used, and drying after application is done using electron beams instead of heat. Because of the irradiation, there is no concern that the coloring agent will develop color during drying, and it is also excellent in workability because it hardens extremely instantaneously.

[Brief explanation of the drawing]

FIG. 1 is a sectional view schematically showing a heat-sensitive recording material according to an embodiment of the present invention. 1...Support, 2...Thermosensitive coloring layer, 5...Protective layer.

Claims (1)

[Claims for Utility Model Registration] A support, a microcapsule formed by encapsulating a film-forming substance around a dye, and a film-forming substance encapsulated around a heat-sensitive element for coloring the dye. a heat-sensitive coloring layer formed by applying a heat-sensitive coloring agent having a micro-encapsulated material on the surface of the support; A heat-sensitive recording material comprising a protective layer formed.