JPS599909Y2 - Peelable label for thermal recording - Google Patents

Description

[Detailed description of the invention] The present invention relates to a release label that can be recorded using a heat-sensitive recording method, that is, a release label for heat-sensitive recording. Regarding a peelable label for heat-sensitive recording.

Conventionally, peelable labels have been widely used as product labels for indicating the capacity, price, quality, etc. of products, address display labels attached to mailed items, and the like.

Some of these peelable labels are displayed and recorded using a printer, and the printing methods such as the stamping method and the type ribbon method have been put into practical use.

However, these recording methods have drawbacks such as noise and the need to replenish ink and replace the ribbon, so there has been a strong desire to adopt a thermal recording method that does not require such things.

However, when trying to apply the thermal recording method to recording on peelable labels, although it has the above-mentioned advantages, it also has major drawbacks.

In other words, as a heat-sensitive recording material, it is practical to use a color-forming system consisting of a colorless or light-colored leuco dye and an acidic substance that causes the color to develop when heated, since the recorded image is clear and there is little shelf life blurring. Most advantageously, when applied to a product label, a peelable label using this type of heat-sensitive recording material can be wrapped over the label with a vinyl chloride film, polypropylene film, etc., or the product wrapped with these films can be This is because when a peelable label is attached to the top of the product and the products are stored or displayed one on top of the other, the thermally recorded image disappears to the point of being unreadable after only half a day.

This phenomenon of recorded images disappearing when stacked with organic resin films or sheets often occurs in the case of address labels for mailed items, and for this reason, thermal methods are not recommended as a recording method for release paper. This has prevented recruitment.

The inventor of the present invention has carefully studied the above-mentioned phenomenon and found that it is caused by a plasticizer present on the surface of the resin film or exuded from inside the film.

That is, although a plasticizer is added to form a film from these organic resins, the plasticizer decomposes the color-forming dye once formed by heating and erases the color.

Therefore, the present inventors proposed that a barrier layer made of a water-soluble polymer substance be provided on the thermosensitive coloring layer to prevent the plasticizer contained in the resin film from coming into direct contact with the thermosensitive layer.

However, when applied to product labels, for example, condensed water tends to accumulate under the conditions of use, and when products are stacked,
This has the disadvantage that products adhere to each other through the labels, causing damage to the products or packaging.

Therefore, in the present invention, a release paper is pasted on the back side of the support via a pressure-sensitive adhesive layer, and the surface of the support is heat-sensitive coloring containing a colorless or light-colored leuco dye and an acidic substance as coloring ingredients. A barrier layer is sequentially provided from a water-soluble polymeric material and a water-resistant agent that reacts with the polymeric material itself such as a condensation or crosslinking reaction to make the water-soluble polymeric material water-resistant. It is an object of the present invention to provide a peelable label for heat-sensitive recording.

Examples of water-soluble polymer substances forming the barrier layer include:
Polyvinylene realconole, canoleboxymethylcellulose, methylcellulose, ethylcellulose, hydroxymethylcellulose, hydroxyethylcellulose,
Hydroxyprobyl cellulose, polyacrylamide,
Examples include teppan, gelatin, casein, and polyvinylpyrrolidone.

In addition, formaldehyde, glyoxal, chromium, etc. are examples of water-resistant agents that react with these substances such as condensation or cross-linking reactions to make the water-soluble polymer substances water-resistant.
Examples include melamine, melamine-formaldehyde resin, polyamide resin, polyamide epichlorohydrin resin, and the like.

These waterproofing agents have a 20 to 10
Preferably, it is added at a rate of 0%.

The thickness of the barrier layer is preferably about 1μ to 10μ,
If it is less than 1 μm, it is difficult to form a layer with a uniform thickness, and if it is more than 10 μm, heat conduction to the thermosensitive coloring layer is not quick enough, and a large amount of thermal energy is required for recording.

In addition, 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 into contact with the organic resin film all day and night. If left unattended, the recorded images will disappear and become unreadable.

By using a water-soluble polymer material for the barrier layer as in the present invention, recorded images can be maintained semi-permanently without disappearing.
It can be maintained clearly, and the purpose of the present invention can be achieved.

By adding a waterproofing agent, its function can be exhibited even more stably.

In addition, the running performance of the thermal head is improved by adding a head running improving agent used in conventional heat-sensitive coloring layers to the barrier layer of the present invention to the extent that it does not inhibit the function of the water-soluble polymer substance. Or a coloring agent may be added to facilitate classification.

In addition, the heat-sensitive coloring layer can be made of paper, synthetic resin sheet, or
The layer is formed on a support made of metal-deposited paper or the like, and conventionally known leuco dyes, acidic substances, and binders are used to form the layer, and examples thereof are shown below.

1 leuco dye crystal violet lactone, 3-indolino 3
-I) monodimethylaminophenyl-6 dimethylaminophthalide, 3-diethylamino-7-chlorofluoran,
3-diethylamino-7-cyclohexylaminofluorane, 3-diethylamino-5-methyl-7-t-butylfluorane, 3-diethylamino-6-methyl 7-anilinofluorane, 3-diethylamino-6-methyl-7-
1) Monobutylanilinofluorane.

2 Acidic substances 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'-ethylenebis(2-methylphenol), 4,4'-thiobis(6-t-butyl-3-methylphenol).

3 Binders Water-soluble materials such as polyvinyl alcohol, methoxycellulose, hydroxyethynoresenolose, canoleboxymethylcellulose, polyvinylpyrrolidone, polyacrylamide, polyacrylic acid, starch, gelatin, polystyrene, vinyl chloride-vinyl acetate copolymer, polybutyl methacrylate, etc. liquid or aqueous emulsion.

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 such as a silicone resin or 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 shown in FIG.

That is, in FIG. 1, reference numeral 1 denotes a support, on the back of which a release paper 3 consisting of a mount 5 and a release layer 4 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, a water resistant agent, and, if desired, a head running improver, is formed on the thermosensitive coloring layer 6. is in great shape.

Reference numeral 9 in the figure collectively indicates the peeled portions.

FIG. 2 is a perspective view of an embodiment of the heat-sensitive recording release label 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 1 and Comparative Example 1 Dispersions A and B were prepared by pulverizing the following bokmin for 24 hours using a ball mill, and dispersions A and B were further mixed to prepare a heat-sensitive coloring layered liquid.

Dispersion A Crystal violet lactone 1.5 parts by weight Polyvinyl alcohol (20% aqueous solution) 5.0 parts by weight Water 43.5 parts by weight Dispersion B Bisphenol A 6.0 parts by weight Calcium carbonate 3.0 parts by weight Stearamide 1 .0 parts by weight Polyvinyl alcohol (20% aqueous solution) 10.0 parts by weight Water 30.0 parts by weight? 50 g/m' of heat-sensitive coloring layered solution was applied to one side of high-quality paper to a solid adhesion of 5 g/m, and dried.
A sheet of thermal paper was produced.

A 5% aqueous solution of polyvinyl alcohol was placed on one of the heat-sensitive coloring layers, and 25 parts by weight of a 20% aqueous solution of polyvinyl alcohol and 3.2 parts by weight of a 30% aqueous solution of methylolmelamine resin were placed on the other heat-sensitive coloring layer. A mixed solution of 100% and 100% was applied and dried to form a barrier layer of about 5 μm.

Next, the surfaces of the supports of the two types of thermal paper prepared above were laminated onto a release paper coated with an SBR latex pressure-sensitive adhesive layer on a silicone resin release layer, and the release paper for comparison and the present invention was prepared. A label was created.

Color development was recorded on the thermosensitive coloring layer of each release label by heating printing using a thermal gradient tester (manufactured by Toyo Seiki Co., Ltd.).

When a vinyl chloride film was layered on the surface of each of these peel-off labels and the decrease in color density was examined, the initial image density of 1.15 was maintained in each case even after one week, and no decrease in density was observed. .

Next, water droplets were placed on the barrier layers of both release labels, and art paper was closely stacked thereon and left in a dry atmosphere for one day and night.

In contrast to the comparative heat-sensitive recording release label that had a barrier layer made only of polyvinyl alcohol, the art paper stuck to it, whereas the heat-sensitive recording label of the present invention had a barrier layer made of polyvinyl alcohol and a melamine resin as a water-resistant agent. The release label did not stick to the art paper.

Production Example 2 Dispersions D and E were prepared by pulverizing and dispersing the following substances using a ball mill for 24 hours.

A mixture of these dispersions D and E is applied onto a high-quality paper, and after drying, aqueous solution F is applied on the coated layer to a dry thickness of about 5 ml.
It was applied to a thickness of μ and allowed to dry.

Dispersion D 3-dimethyl-6-methyl-7-anilinofluorane
1.5 parts by weight Polyvinyl alcohol (20% aqueous solution) 5.0 parts by weight Water 43.5 parts by weight Dispersion E Bisphenol A 6.0 parts by weight Stearamide 1.0 parts by weight Polyvinyl alcohol (20% aqueous solution) 10. 0 parts by weight Water 33.0 parts by weight Aqueous solution F Starch oxide (20% aqueous solution) 25.0 parts by weight Glyoxal (40% aqueous solution) 11.4 parts by weight Ammonium chloride 1.1 parts by weight Water 62.5 parts by weight This thermal record A release label for heat-sensitive recording of the present invention was prepared by pasting a release paper coated with an SBR latex pressure-sensitive adhesive layer on a silicone resin release layer on the back side of the paper.

This label has the same image preservation properties as the one according to Production Example 1.
It had excellent water resistance.

Comparative Example 2 A peelable label for heat-sensitive recording was produced in the same manner as in Production Example 2, except that the aqueous solution F in Production Example 2 was replaced with the following organic solvent solution H, and the same test as in Production Example 1 was conducted.

Organic solvent solution H Polyvinyl alcohol (10% aqueous solution) 50 parts by weight Paraffin wax emulsion (25% aqueous solution) 25
Part by weight Water: 25 parts by weight The image density before the test was 1.16, but when a vinyl chloride film was placed on top of the colored image and left for one week (25°C), the image density became 0.42. , the plasticizer resistance was poor.

Comparative Example 3 A peelable label for heat-sensitive recording was produced in the same manner as in Production Example 2, except that the aqueous dispersion I described below was used instead of the aqueous solution F in Production Example 2, and the same test as in Production Example 1 was carried out.

Aqueous dispersion ■ Vinyl chloride vinyl acetate copolymer [50% solids] 10 parts by weight water 9
0 parts by weight The image density before the test was 1.33, while the image density after the test was 0646, indicating poor plasticizer resistance.

In addition, there were some problems in water resistance as well, similar to the case of Comparative Example 1.

Comparative Example 4 In place of the aqueous dispersion ■ in Comparative Example 3, the following coating liquid J was used.
The same procedure as Comparative Example 3 was carried out except that .

The image density before the test was 1.16, whereas the image density after the test was 0.42, indicating poor plasticizer resistance.

There was also a problem with water resistance.

Furthermore, in the case of the present invention, in addition to polyvinyl alcohol, methinoresenolose, canoleboxymethinoresenolose, ethyl cellulose, hydroxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, polyvinyl alcohol, etc. Similar effects were obtained using acrylamide, starch, and polyvinylpyrrolidone, respectively.

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. This method made it possible to apply the heat-sensitive recording method, which had been considered difficult, and was successful 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. 1...Support, 2...Pressure sensitive adhesive layer, 3
...Release paper, 4...Release layer, 5...
...Mount, 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 pasted on the back side of the support via a pressure-sensitive adhesive layer,
The surface of the support (this is a heat-sensitive coloring layer containing a colorless or light-colored leuco dye and an acidic substance as a coloring component, and a reaction such as a condensation or crosslinking reaction between a water-soluble polymeric substance and the polymeric substance itself) 1. A heat-sensitive recording peeling label, characterized in that a barrier layer comprising a water-resistant agent and a water-resistant agent that makes the water-soluble polymer substance water-resistant is sequentially provided.