JPH11231785A - Thermal recording label - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily produce many heat-sensitive recording labels to easily be worked and different from one another in color at a low cost by providing a colored layer on one face or a transparent polymer film and sticking the face where the colored layer of a heat-sensitive recording body in which a heat sensitive color developing layer is provided on the opposite face to the face where the peeling layer of peeling paper is provided, through an adhesive. SOLUTION: A heat-sensitive color developing layer 5 is formed on one face of a transparent polymer film 4 as a substrate, a colored layer 3 is formed on the opposite face and an adhesive layer 2 and peeling paper 1 are successively laminated on the colored layer 3. A known transparent polymer film as before can be used as the film 4 to be used for the substrate. The peeling paper 1 and the adhesive layer 2 are not limited if they are used for a conventional peeling label. As a leuco compd., a developer and a binder constituting the color developing layer 5, known materials as before are used. A more stable recording body is obtd. by providing a protective layer 6 mainly composed of a water-soluble polymer and/or a synthetic resin emulsion on the color developing layer 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal recording label on which an image can be recorded by a thermal recording method. More specifically, the present invention relates to an improvement in a thermosensitive recording label provided with an identification function by coloring.

[0002]

2. Description of the Related Art A heat-sensitive recording label in which a release paper is adhered to the back surface of a support via an adhesive layer, and a heat-sensitive coloring layer containing a heat-sensitive coloring component is formed on the surface of the support,
A color image such as character information or a bar code ゛ is formed by the thermal recording method.

[0003] In recent years, in this type of thermal recording label,
In order to meet the demands of recording a lot of character information or reducing the barcode recording area, improving dot reproducibility and obtaining high-definition printing, etc. In recent years, thermosensitive recording labels using a polymer film as a support have been used.

[0004] Further, a heat-sensitive label in which the background portion of the label is colored has come to be used because of its easy identification.
In order to satisfy these demands, the present inventors have proposed a technique disclosed in Japanese Utility Model Application Laid-Open No. 4-10.
Japanese Patent No. 7076 discloses a method in which a transparent polymer film is used as a support and a colorant is contained in a pressure-sensitive adhesive layer on the back surface so that the background portion can be colored in an arbitrary color without changing the composition of the thermosensitive coloring layer on the front surface. A heat-sensitive recording label that can print and obtain high-definition printing characteristics was proposed.

[0005] Certainly, an excellent label could be manufactured by this method, but the following problems were caused by the following examination. That is, since the release paper is pasted through the colored adhesive layer containing the coloring agent, the adhesive properties such as the adhesive strength and the peeling strength of the adhesive and the aging thereof are influenced by the coloring agent for each color. A new problem arises in that a change occurs in the change characteristics and it is difficult to design an adhesive.

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned drawbacks and to provide a heat-sensitive recording label which can produce colored labels of any color at a low cost by simple means.

[0007]

The heat-sensitive label of the present invention has a coloring layer provided on one side of a transparent polymer film and a coloring layer of a thermosensitive recording medium provided with a heat-sensitive coloring layer on the other side. It is obtained by sticking the surface and the surface provided with a release layer of release paper via an adhesive.

According to the present invention, a transparent polymer film is provided with a coloring layer on one surface, and on the other surface, a surface provided with a coloring layer of a thermosensitive recording medium provided with a thermosensitive coloring layer and a release layer of release paper. It is a heat-sensitive recording label in which the provided surface is adhered via an adhesive.

Further, the present invention is a thermosensitive recording label comprising a protective layer containing a water-soluble polymer and / or a synthetic resin emulsion as a main component on the thermosensitive coloring layer.

Further, in the present invention, a protective layer mainly composed of a water-soluble polymer and / or a synthetic resin emulsion is provided on the thermosensitive coloring layer, and a second protective layer mainly composed of an ultraviolet curable resin is further provided. Thermal label.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, each element constituting the present invention will be described in more detail. First, the support will be described. As the transparent polymer film used for the support of the present invention, conventionally known ones can be used, for example, polyethylene, polypropylene, polyethylene terephthalate, polycarbonate, polystyrene, nylon, cellulose diacetate. And cellulose triacetate. These transparent polymer films as additives for improving performance in a range that does not impair the transparency of the film, for example, an antioxidant, an antistatic agent, a slip agent,
An inorganic pigment or the like may be used.

Further, if necessary, the adhesiveness between the support and the thermosensitive coloring layer and / or the coloring layer can be enhanced by subjecting the transparent polymer film to a corona discharge treatment or applying an ionomer resin. It is necessary that the support is a synthetic resin film which is transparent enough to see through the following colored layer.

Although a colored label can be obtained even if a colored layer is provided between the thermosensitive coloring layer and the support pair, a problem arises in that the chemical used for the coloring layer affects the thermosensitive coloring layer and reduces the storage stability. However, there is a problem that it is difficult to obtain a glossy recording medium.

The release paper provided on the back surface of the support and the pressure-sensitive adhesive layer for bonding the release paper to the support can be any of those used in conventional release labels. For example, as a release paper, a release layer of silicone resin or the like provided on a backing such as paper, and the adhesive used for the adhesive layer is basically an adhesive composed of the following elastic body and a tackifier. Can be used.

(I) Elastic body: recycled rubber, SBR (styrene / butadiene rubber), polyisoprene / butyl rubber,
Bunner N (butadiene acrylonitrile rubber), polyvinyl ether (ethyl or higher), polyacrylate ester (ethyl or higher). (Ii) Tackifier: polyterpene resin, gum rosin, rosin ester and rosin derivative, oil-soluble phenol resin, coumarone indene resin, petroleum hydrocarbon resin.

In the present invention, as the coloring agent for the back surface of the transparent support, any of those used in conventional printing inks can be used. For example, gravure ink, letterpress ink, and lithographic ink can be used. The composition of the ink also includes a colorant, a vehicle, and an auxiliary agent. Generally, the colorant is a dye, a pigment, an extender, or the like, and the vehicle is a resin or a solvent. Examples of the auxiliary agent include an antistatic agent, a leveling improver added for improving the properness of the ink, and a friction improver, a slip agent, a curing agent, etc., added for improving the physical properties. Add these.

In addition to the solvent type printing method, a backside coloring process by a conventional coating method is also possible. For example, the above-mentioned colorant, vehicle, a coating solution comprising an auxiliary agent, a normal blade coater, air knife coater, bar coater,
It can also be coated with a reverse roll coater.

Further, the above-mentioned back surface coloring process can be carried out by a water-based coating liquid. A water-soluble polymer and / or a synthetic resin emulsion is used as a main component, and the above-mentioned coloring agent and auxiliary agent are mixed, stirred and applied. This coating can be performed by a blade coater, an air knife coater, a bar coater, a reverse roll coater, or the like.

As the leuco compound, the color developer and the binder constituting the thermosensitive coloring layer, conventionally known ones are used. An example is shown below. Leuco compounds are colorless or pale-colored and are substances that form a color by reacting with the organic acids described below. And phenoxazine, spiropyran, indoline and indigo derivatives. Preferred leuco compounds include, for example, crystal violet lactone, 3-diethylamino-6-methyl-7-anilinofluoran, 3- (N-ethyl-p-toluidino) -6-methyl-7-amylinofluoran, -Diethylamino-6-metiru-7
-(Ortho, para-dimethylanilino) fluoran, 3
-Piperidino-6-methyl-7-anilinofluoran,
3- (N-cyclohexyl-N-methylamino) -6
Methyl-7-anilinofluoran, 3-diethylamino-7- (ortho-chloroanilino) fluoran, 3-diethylamino-7- (meta-trifluoromethylanilino) fluoran, 3-diethylamino-6-methyl-chlorofluoran , 3-diethylamino-6-methyl-fluoran, 3- (N-isoamyl-N-ethylamino)
-6-methyl-7-anilinofluoran and 3-dibutylamino-6-methyl-7-anilinofluoran.

The acidic substance used as a color developer is a solid at room temperature, melts by heating, and comes into contact with the leuco dye compound to become a color developer, and includes various phenolic substances, fatty acids, and aromatic substances. Examples of carboxylic acids include gallic acid, salicylic acid, 1-hydroxy-2-naphthoic acid, o-hydroxybenzoic acid, m-hydroxybenzoic acid, 2-hydroxy-p-toluic acid, 3,5-xylenol, Thymol, p-tert-butylphenol,
4-hydroxyphenoxide, methyl-4-hydroxybenzoate, 4-hydroxyacetophenone, α-naphthol, β-naphthol, catechol, resorcinol,
Hydroquinone, 4-tert-octylcatechol,
4,4'-sec-butylidenephenol, 2,2'-
Dihydroxydiphenyl, 2,2′-methylenebis (4
-Methyl-6-tert-butylferol), 2,
2'-bis (4-hydroxyphenyl) propane (alias: bisphenol A), 4,4'-isopropylidenebis (2-tert-butylphenol), pyrogallol, phloroglucin, phloroglucin carboxylic acid, p-
Methylphenol, p-phenylphenol, 4,4
'-Cyclohexylidenediphenol, 4,4'-isopropylidenedicatechol, 4,4'-benzylidenediphenol, 4,4'-isopropylidenebis (2-chlorophenol), 3-phenylsalicylic acid, 3,5-
Di-tert-butylsalicylic acid 1-oxy-2-naphthoic acid, gallic acid ester, salicylic acid ester, p-
Hydroxybenzoic acid ester, 4-hydroxyphthalic acid ester, 2- (4-hydroxyphenyl) 2- (3 ′
-Hydroxyphenyl) propane, 4,4'-dihydroxy-3,3'-diisopropyldiphenyl-2,2 '
-Propane and the like.

The binder used in the heat-sensitive coloring layer is mainly composed of a water-soluble binder, in which a dye and a color developer dispersed in fine particles are fixed to each other while being separated from each other.
Examples include polyvinyl alcohol, epoxy-modified polyvinyl alcohol, methyl cellulose, carboxymethyl cellulose, hydroxyethyl cellulose, polyacrylic acid, casein, gelatin, starch, and derivatives thereof.

If necessary, other additives such as clay, calcium carbonate, synthetic silica, and the like may be added to the thermosensitive coloring layer of the present invention.
Inorganic or organic pigments such as aluminum hydroxide, talc, titanium oxide, zinc oxide, etc., antioxidants for storage stability, ultraviolet absorbers, water resistant agents for improving water resistance, phenolic resins, surfactants, conventionally Waxes used,
Metal salts of higher fatty acids and the like can be added. If necessary, a heat-fusible substance that promotes color development may be added. However, with the thermosensitive coloring layer provided on the support,
When viewed from the heat-sensitive coloring layer side, it is necessary to ensure transparency such that the coloring layer on the back surface of the support can be identified.

The coating material for forming a thermosensitive coloring layer of the present invention comprises the above-mentioned leuco compound, an organic acid or an ester thereof, and additives such as a pigment and a sensitivity adjuster, which are added as necessary, at an appropriate concentration of polyvinyl alcohol. It is adjusted by pulverizing and dispersing in an aqueous medium containing a binder such as alcohol using a ball mill, a sand grinder-pulverizer or the like. It is advantageous in terms of color development efficiency that each constituent material be as fine as possible.
It is preferable that the particle size is 3 μm or less. The heat-sensitive paint thus obtained is applied on an ionomer resin as a support and dried to obtain a heat-sensitive recording material of the present invention. The application of the above-mentioned heat-sensitive paint is performed using a normal blade coater, air knife coater,
It can be performed by a bar coater, a reverse roll coater or the like.

It is preferable to provide a protective layer containing a water-soluble polymer and / or a synthetic resin emulsion as a main component on the thermosensitive coloring layer because a more stable recording medium can be obtained.
For this protective layer, any overcoating agent used in the conventional overcoat layer can be used.
A, modified PVA, starch, casein, and a synthetic resin emulsion can be used.

Further, by providing a second protective layer mainly composed of an ultraviolet curable resin on the protective layer, it is possible to obtain an excellent label which is glossy and is not affected by mechanical pressure. ,preferable. In a state where one or two protective layers are provided, it is necessary that the colored layer on the back surface of the support is sufficiently transparent so that the colored layer can be identified when viewed from the protective layer side.

The method for obtaining the heat-sensitive label of the present invention includes:
(1) A method of obtaining a recording medium in which a coloring layer is provided on a transparent film in advance and a heat-sensitive coloring layer is provided on the opposite surface, and then attaching the recording medium to a release paper via an adhesive, (2) providing a coloring layer on the transparent film There is a method in which a thermosensitive coloring layer is formed on the opposite surface after adhering to a release paper via an adhesive, but it is determined by the tensile strength, heat resistance and the like of the film used.

[0027]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The structure of the thermal label of the present invention formed by using the above materials is as shown in FIGS. That is, in FIG. 1, 1 is a release paper, 2 is an adhesive layer, 3 is a colored layer, 4 is a support made of a transparent synthetic resin film, and 5 is a thermosensitive coloring layer. FIG. 2 shows a configuration in which 6 protective layers are added to FIG. FIG. 3 shows a configuration obtained by adding the ultraviolet-curable resin protective layer 7 to FIG.

The present invention will be described more specifically with reference to production examples. Example 1 Corona discharge treatment was applied to both surfaces of a transparent biaxially stretched PP film having a thickness of 30 μm. Next, an ink having the following composition was adjusted on one surface with a 165 mesh, Zahn cup # 3 so as to have a duration of 20 seconds, and dried with a gravure coater. Toyo Ink Multi Set (Blue) 100g Toyo Ink LPNYB Additive 3g Toyo Ink 150T-C 5g Toyo Ink LP-402 25-30g

Next, a liquid for forming a thermosensitive coloring layer was prepared by dispersing the liquids A and B having the following compositions with a paint shaker (manufactured by Toyo Seiki) for 10 hours. Liquid A: Leuco dye 3-dibutylamino-6-methyl-7-anilinofluoran 5 g Zinc stearate 5 g Polyvinyl alcohol (12% liquid) 40 g Water 50 g Liquid B: Bisphenol A 10 g Zinc stearate 3 g Polyvinyl alcohol (12% Liquid) 40g water 47g

Next, 100 g of solution A, 100 g of solution B, 10 g of silica (manufactured by Mizusawa Chemical Co., p-527), 30 g of SBR latex (Nippon Zeon PT-1051) and 60 g of water were mixed and stirred to form a heat-sensitive coating solution. This coating solution was applied to the surface of the support to which the colorant was not applied using a Meyer bar so that the coating material after drying was 8 g / m ^2, and dried to obtain a thermosensitive recording medium.

Further, an adhesive layer (a coating amount of 30 g / m ² ) made of styrene-butadiene rubber as an elastic body and a polyterpene resin as a tackifier is provided on the back surface of the support. Rice tsubo 60g / m
² ) was applied to prepare a thermal recording label of the present invention.

(Example 2) Except that Toyo Ink Multiset (Yellow) was used in place of Toyo Ink Multiset (Blue), the main colorant for the back surface of the support used in Example 1, was used. A label according to the invention was made.

(Example 3) After obtaining a recording medium from which the silica was removed from the heat-sensitive coating composition in Example 1, a protective layer having the following composition was applied at ² g / m ² to obtain a label of Example 3. . Polyvinyl alcohol 12% solution (Kuraray Kuraray Poval 105) 400 g Aluminum hydroxide (Showa Denko Higlylite H-42) 20 g Zinc stearate 30% dispersion (Chukyo Yushi D-523) 30 g Glyoxal 40% solution 25 g Water 400 g

Example 4 On the label of Example 3, 2 g / m 2 of an ultraviolet curable resin (N-1815 manufactured by Nippon Kayaku)
^Two coatings were performed to obtain a glossy label of Example 4.

(Printing Test) The label prepared as described above was added to a commercially available label printer (XP-62 manufactured by Nisshinbo).
Printing was performed in step 50). The obtained image has good dot reproducibility and is vivid, contrastable and easy to see because the support is colored.

[0036]

As described above, according to the present invention, the support or the thermosensitive coloring layer itself is not colored by adding or kneading a coloring agent, but merely by coloring the back surface of the support.
It is easy to process and is more suitable for small lot production of labels. By arbitrarily changing the colored layer on the back surface of the support, there is an effect that labels of many different colors can be easily and inexpensively manufactured. Also, the present invention
It was confirmed that the use of a transparent synthetic resin film for the support also had the advantage of good recording properties.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an embodiment of a thermal label of the present invention.

FIG. 2 is a schematic configuration diagram of another embodiment of the present invention.

FIG. 3 is a schematic configuration diagram of still another embodiment of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 release paper 2 adhesive layer 3 colored layer 4 support 5 thermosensitive coloring layer 6 protective layer 7 ultraviolet curable resin layer

Claims (3)

[Claims] 1. A heat-sensitive coloring layer is provided on one surface of a transparent polymer film, a coloring layer is provided on the opposite surface, and an adhesive layer and a release paper are laminated on the coloring layer in this order. Thermal recording label. 2. A thermosensitive recording label according to claim 1, wherein a protective layer containing a water-soluble polymer and / or a synthetic resin emulsion as a main component is provided on said thermosensitive coloring layer. 3. A protective layer comprising a water-soluble polymer and / or a synthetic resin emulsion as a main component is provided on said thermosensitive coloring layer.
2. The thermal recording label according to claim 1, further comprising a second protective layer mainly composed of an ultraviolet curable resin.