JPS6226216Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a heat-sensitive recording release label that can obtain a recorded image using a heat-sensitive recording method.More specifically, during long-term storage, the recorded image disappears due to the organic resin film on the heat-sensitive coloring layer. This invention relates to a peelable label for heat-sensitive recording that will not be damaged.

Conventionally, record peeling labels have been widely used as product labels to display the capacity, price, quality, etc. of products, address labels attached to mailed items, and office labels used for organizing documents. It is being Conventionally, the main methods for recording on these labels have been the stamping method and type ribbon method, but these methods have drawbacks such as noise, the need to replenish ink, and the need to replace the ribbon. Therefore, there has been a strong desire for recording by a heat-sensitive recording method that does not require this.
However, when trying to apply the heat-sensitive recording method to recording on a peelable label, although it has the above-mentioned advantages, it also has drawbacks, and this has greatly hindered the application of the heat-sensitive recording method to release labels. That is, in many cases, a peelable label is wrapped with an article in a packaging film or protective film such as polyvinyl chloride film or polypropylene film, or is brought into contact with the article. The recorded images above would disappear over time, impairing the preservation of the recorded images.

The present invention is intended to solve the above-mentioned conventional drawbacks and to enable application of heat-sensitive recording type peelable labels. More specifically, the object of the present invention is to provide a peelable label for heat-sensitive recording that can record recorded images that can withstand long-term storage without being corroded by organic resin films and the like.

As a result of repeated research in view of the purpose of the present invention, we have found that the disappearance of recorded images by the organic resin film mentioned above is mainly caused by the plasticizer present in the organic resin film penetrating into the heat-sensitive coloring layer of the release label and being heated. It was discovered that this phenomenon occurs to decompose the colored dye once formed, and a barrier layer made of a water-soluble polymer material that does not allow the plasticizer to pass through is provided on the layer to prevent the plasticizer from penetrating into the heat-sensitive coloring layer. They discovered that this can be prevented by doing this, and came up with the present invention.

That is, in the present invention, a release paper is attached to the back side of the support via a pressure-sensitive adhesive layer, and a heat-sensitive coloring material containing a colorless or light-colored leuco dye and an acidic substance as coloring components is attached to the surface of the support. This is a peelable label for heat-sensitive recording in which a layer and a barrier layer made of a water-soluble polymer material are sequentially formed.

To further explain the present invention, the water-soluble polymer substances include polyvinyl alcohol, carboxymethylcellulose, methylcellulose, ethylcellulose, hydroxymethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, polyacrylamide, starch, gelatin, casein, polyvinylpyrrolidone, etc. For example, these are formed into an aqueous solution, applied onto a heat-sensitive coloring layer, and dried to form a barrier layer. The thickness of the barrier layer is preferably about 1μ to 10μ; if it is less than 1μ, it will be difficult to form a layer with a uniform thickness, and if it is more than 10μ, the heat conduction to the thermosensitive coloring layer will not be quick enough, and recording will be difficult. of heat energy is required.

Furthermore, when a polymeric substance soluble in organic solvents such as polystyrene resin is used in the barrier layer, the storage stability of recorded images can be improved somewhat compared to conventional methods, but it still does not come in contact with the organic resin film all day and night. If left unattended, the recorded images will disappear and become unreadable. Only by using a water-soluble polymeric substance for the barrier layer as in the present invention can the recorded image be kept clear semi-permanently without disappearing, and the object of the present invention can be achieved.

In addition, a head running improver used in conventional heat-sensitive coloring layers is added to the barrier layer of the present invention to an extent that does not inhibit the function of the water-soluble polymeric substance to improve the running properties of the thermal head. Or a coloring agent may be added to facilitate classification.

Furthermore, the heat-sensitive coloring layer is conventionally formed on a support made of paper, synthetic resin sheet, metallized paper, etc., but the leuco dye, acidic substance, and binder constituting the layer are conventionally known ones. is used, an example of which is shown below.

1 Leuco dye Crystal violet lactone, 3-indolino-3-p-dimethylaminophenyl-6
-dimethylaminophthalide, 3-diethylamino-7-chlorofluorane, 3-diethylamino-7-cyclohexylaminofluorane, 3
-diethylamino-5-methyl-7-t-butylfluorane, 3-diethylamino-6-methyl-7-anilinofluorane, 3-diethylamino-6-methyl-7-p-butylanilinofluorane 2 Acidic substance 2,2-bis(4'-oxyphenyl)propane (also known as bisphenol A), 4-phenylphenol, 4-hydroxyacetophenone,
2,2'-dihydroxydiphenyl, 2,2'-methylenebis(4-chlorophenol), 2,
2'-methylenebis(4-methyl-6-t-butylphenol), 4,4'isopropylidenediphenol, 4,4'-isopropylidenebis(2
-chlorophenol), 4,4'-isopropylidene bis(2-methylphenol), 4,4'-
Ethylene bis(2-methylphenol), 4,
4'-thiobis(6-t-butyl-3-methylphenol).

3 Binder Water-soluble or water-based emulsion such as polyvinyl alcohol, methoxycellulose, hydroxyethylcellulose, carboxymethylcellulose, polyvinylpyrrolidone, polyacrylamide, polyacrylic acid, starch, gelatin, polystyrene, vinyl chloride-vinyl acetate copolymer, polybutyl methacrylate, etc. .

Furthermore, additives known in the field of heat-sensitive recording materials may also be added to the heat-sensitive coloring layer.

The release paper provided on the back side of the support and the pressure-sensitive adhesive layer that adheres it to the support can be any of those used in conventional release labels. A release layer made of silicone resin or the like and a pressure-sensitive adhesive layer can be formed by using SBR latex.

The structure of the heat-sensitive recording release label of the present invention formed using the above-mentioned materials is as shown in FIG. That is, in FIG. 1, 1 is a support, and on the back side there is a release paper 3 formed by providing a release layer 4 on a mount 5.
is attached via a pressure-sensitive adhesive layer 2. On the surface of the support 1, the above-mentioned colorless or light-colored leuco dye,
A thermosensitive coloring layer 6 containing an acidic substance, a binder, and further additives is formed, and then a barrier layer 7 containing the water-soluble polymeric substance and, if desired, a head run improving agent, is formed on the thermosensitive coloring layer 6. . Reference numeral 9 in the figure collectively indicates the peeled portions.

FIG. 2 is a perspective view of an embodiment of the release label for heat-sensitive recording of the present invention, which is wound into a roll with a core tube 8 as the core. The peelable portion 9 is separated into appropriate sizes and attached.

The present invention will be further explained in detail with reference to manufacturing examples.

Production Example Dispersions A and B were prepared by pulverizing the following components for 24 hours using a ball mill, and dispersions A and B were further mixed to prepare a thermosensitive coloring layer forming liquid.

[Dispersion liquid A]

Crystal Violet Lactone 1.5 parts by weight Polyvinyl alcohol (20% aqueous solution)
5.0 〃 Water 43.5 〃 [Dispersion B] Bisphenol A 6.0 parts by weight Calcium carbonate 3.0 〃 Stearic acid amide 1.0 〃 Polyvinyl alcohol (20% aqueous solution)
10.0 〃 Water 30.0 〃 This heat-sensitive coloring layer forming liquid was applied to the surface of the support 1 made of high-quality paper with a basis weight of 50 g/m ² to a dry adhesion amount of 5 g/m 2 .
m ² and dried to form a thermosensitive coloring layer 6. On top of the thermosensitive coloring layer 6, a 5% aqueous solution of polyvinyl alcohol was further coated and dried to form a barrier layer 7 with a thickness of about 2 μm. Next, a pressure-sensitive adhesive layer 2 made of SBR latex is coated on a release paper 3 on which a release layer 4 made of silicone resin is provided on a mount 5, and this is pasted on the back surface of the support 1. A removable record label was created.

Comparative Example 1 A comparative heat-sensitive recording release label was prepared in the same manner as in Production Example except that the barrier layer 7 was not formed.

Each label created as described above was heated and printed using a thermal gradient tester (manufactured by Toyo Seiki Co., Ltd.), and then covered with a polyvinyl chloride film to measure the decrease in printing density. In the case of Comparative Example 1, the density of 1.15 immediately after printing was maintained even after 24 hours, whereas in the case of Comparative Example 1, the density of 1.15 immediately after printing decreased to 0.34 after 24 hours, making it unreadable. .

Comparative Example 2 A thermosensitive color forming layer was formed in the same manner using the heat sensitive color forming liquid of the production example, and a 5% benzene solution of polystyrene (molecular weight approximately 20,000) was further coated on the heat sensitive color forming layer 6, and immediately Dry, approximately 2μ barrier layer 7
was formed. Next, in the same manner as in the production example, a release paper and a pressure-sensitive adhesive layer were provided to prepare a release label for heat-sensitive recording.

The label created as described above was heated and printed using a thermal gradient tester, and then covered with a polyvinyl chloride film to measure the decrease in print density.The density immediately after printing was 1.13, but after 24 hours it decreased to 0.48. However, it was impractical.

As is clear from the above comparative tests, the barrier layer made of a water-soluble polymer material in the present invention has excellent plasticizer resistance without impairing the heat-sensitive recording properties of the heat-sensitive recording material.

Furthermore, in the case of the present invention, in addition to polyvinyl alcohol, methylcellulose, carboxymethylcellulose, ethylcellulose, hydroxymethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, polyacrylamide, starch, and polyvinylpyrrolidone are used as the water-soluble polymeric substance of the barrier layer 7. A similar effect was obtained.

As described above, the heat-sensitive recording peel label of the present invention has excellent storage stability, and the recorded image does not disappear even when organic resin films are stacked on top of each other. has made it possible to apply heat-sensitive recording methods, which were considered difficult.
This product succeeded in increasing the efficiency of printing work for peelable labels.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing the layer structure of the heat-sensitive recording release label of the present invention, and FIG. 2 is an embodiment of the heat-sensitive recording release label of the present invention. DESCRIPTION OF SYMBOLS 1... Support, 2... Pressure sensitive adhesive layer, 3... Release paper, 4... Release layer, 5... Mounting paper, 6... Thermosensitive coloring layer, 7... Barrier layer, 8... Core tube, 9...Peeling part.

Claims (1)

[Scope of utility model registration request] A release paper is attached to the back side of the support via a pressure-sensitive adhesive layer, and a heat-sensitive coloring layer containing a colorless or light-colored leuco dye and an acidic substance as coloring components, and a water-soluble highly water-soluble layer are attached to the surface of the support. A peelable label for heat-sensitive recording, characterized in that barrier layers made of molecular substances are sequentially formed.