JP2001315435A - Adhesive label for heat sensitive recording - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an adhesive label for heat sensitive recording, which is excellent in the running property of printing even upon applying a high energy and generating no printing trouble while necessitating no release paper. SOLUTION: The adhesive label for heat sensitive recording without necessitating any release paper is provided with a layer constitution, having a heat sensitive recording layer on one side of a substrate, a release agent layer on the heat sensitive recording layer and an adhesive agent layer on the other side of the same, or another layer constitution, having a heat sensitive recording layer on one side of the substrate, a protecting layer on the heat sensitive recording layer, a release agent layer on the protecting layer and the adhesive agent layer on the other side of the substrate. In such an adhesive label for heat sensitive recording, the release agent layer is obtained by curing the release agent of no solvent type through irradiation of radiation and is characterized by the kinetic friction coefficient (based on JIS P 8147) between mutual surfaces of the release agent layer of 0.15-0.40.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat-sensitive recording pressure-sensitive adhesive label which does not require release paper and utilizes a color-forming reaction between a colorless or pale-color developing dye and a color developing compound.

[0002]

2. Description of the Related Art Adhesive labels have been used as labels, stickers, stickers, patches and the like for a wide range of applications such as commercial use, office use, and home use. This adhesive label is generally formed by laminating a surface substrate, an adhesive, and a release paper. Examples of the release paper include high-density paper such as glassine paper, clay-coated paper, base paper for release paper such as polyethylene laminated paper, and plastic film such as polyethylene terephthalate coated with a release agent such as a silicone compound or a fluorine compound. It is used. As the pressure-sensitive adhesive, a solvent-based pressure-sensitive adhesive such as an acrylic or rubber-based pressure-sensitive adhesive, an emulsion-type pressure-sensitive adhesive, a hot-melt-type pressure-sensitive adhesive, or the like is used. Examples of the surface substrate include paper substrates such as high-quality paper, kraft paper, art paper, coated paper, and cast coated paper; heat-sensitive recording sheets, ink-jet recording sheets, recording materials such as thermal transfer image-receiving sheets, and films. Sheet materials such as synthetic paper, metal-deposited sheet, and metal foil are used.

On the other hand, the heat-sensitive recording sheet used as the surface base material utilizes a color-forming reaction between a colorless or pale-color coloring dye and an organic or inorganic color developing compound, and makes the coloring material come into contact with heat. Recording paper in which a recording layer containing both of them is provided on a support so as to obtain a recorded image is well known. Since the heat-sensitive recording sheet is relatively inexpensive, the recording device is compact and the maintenance thereof is easy, it is used not only as a recording medium for facsimile machines and various computing devices but also in a wide range of fields. For example, POS (p.
With the expansion of systemization, cases used as adhesive labels are increasing.

In general, a thermal recording adhesive label is provided with an adhesive layer on the back surface of a thermal recording sheet and then with a release paper. Recording is performed by a label printer, and the label is attached to an adherend. Later, a large amount of release paper was discharged. This release paper not only disturbs the labeling work,
Since the recycled paper cannot be recycled and pulped in ordinary waste paper collection equipment, it is currently incinerated or landfilled. In addition, when used, the thermosensitive recording sheet, adhesive, and release paper are laminated to increase the paper thickness.
There is also a problem that the length of winding of the heat-sensitive recording adhesive label that can be loaded in the label printer is limited, and the label printer must be enlarged or the roll of the heat-sensitive recording adhesive label must be frequently replaced.

[0005] In view of the problem of discarding the release paper, it is conceivable to remove the release paper from the heat-sensitive recording pressure-sensitive adhesive label. In this regard, a release agent layer is provided on the heat-sensitive recording pressure-sensitive adhesive label, and the tape is finished. A method (Japanese Patent Publication No. 4-15110) has been proposed. The pressure-sensitive adhesive label for heat-sensitive recording, a release agent is applied on the recording surface of a general heat-sensitive recording sheet, and a release agent layer is provided by curing, and then,
It is manufactured by forming a pressure-sensitive adhesive layer on the back surface of the support and finishing it into a tape shape. However, when forming the release agent layer, if the release agent is of a solvent type, there is a problem that the solvent permeates the heat-sensitive recording layer and causes the heat-sensitive recording layer to develop color. In addition, when the release agent is a thermosetting release agent, there is a problem in that, when the release agent is applied on the heat-sensitive recording layer and heat required for curing is applied, the heat-sensitive recording layer develops color by the heat.

[0006]

In order to solve the above-mentioned problems, a layer obtained by curing a non-solvent type release agent by radiation as a release agent layer is employed, but new problems have been encountered. The release agent layer of the heat-sensitive recording adhesive label that does not require a release paper must not only function as a release agent, but also have the same functions as general thermosensitive recording materials such as runnability for thermal printers and sticking. No. In particular, when performing thermal recording of two or more colors, it is necessary to perform printing with high applied energy, unlike the case of single-color recording. However, in the case of continuous printing with high applied energy, sticking is likely to occur, whereby the printing shrinks and an accurate printed matter cannot be obtained. Furthermore, the release agent layer is rubbed with a thermal head,
The residue of the release agent accumulates on the thermal head, and there is a possibility that a printing defect such as faint printing may occur.

Further, since the heat-sensitive recording pressure-sensitive adhesive label which does not require a release paper is wound up in a state where the release agent layer and the pressure-sensitive adhesive layer are in contact with each other, when printing with a printer or the like, the pressure-sensitive adhesive layer is released. Printing is performed while peeling from the layer. Since the release agent layer contains a hydrophobic resin as a main component, the release agent layer is easily charged by this release, and dust and the like in the air adhere to the surface of the release agent layer of the heat-sensitive recording adhesive label before printing. When an adhesive label for thermal recording to which foreign matter such as dust adheres is printed on a recording device, the dust or the like stops on the heating element of the thermal head,
There is a possibility that a print failure such as blurring of a recorded image may occur. In addition to the adhesion of dust as described above due to static electricity, there is a possibility that dust or the like may adhere when storing the adhesive label for thermal recording or when loading it into a recording device. Failure may occur.
In particular, when the heat-sensitive recording layer develops two or more colors depending on the heating application conditions from the thermal head, the color tone on the high applied energy side becomes the color tone on the low applied energy side due to the decrease in thermal conductivity, and the color tone Separation becomes difficult.

An object of the present invention is to provide a pressure-sensitive adhesive label for heat-sensitive recording which is excellent in print running property even at a high applied energy and does not require a release paper having no printing trouble.

[0009]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems, and as a result, dust or head residue on the heating element of the thermal head is eliminated every time recording is performed. A release agent layer having an effect (thermal head cleaning effect) was found.

That is, the present invention provides a layer structure having a heat-sensitive recording layer on one side of a support, a release agent layer on the heat-sensitive recording layer and an adhesive layer on the other side, or a heat-sensitive layer on one side of the support. Recording layer,
In a heat-sensitive recording pressure-sensitive adhesive label which does not require a release paper, having a protective layer on the heat-sensitive recording layer, a release agent layer on the protective layer, and a pressure-sensitive adhesive layer on the other surface, the release agent The layer is a layer obtained by curing a solventless release agent by irradiation with radiation,
And the coefficient of kinetic friction between the surfaces of the release agent layers (JIS P 814
7 is 0.15 to 0.40.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The type of release agent, the type of functional group, the type of curing reaction, etc. are not particularly limited as long as the release agent constituting the release agent layer is a solventless type and can be cured by radiation. . For example, a radical polymerization reaction is caused by radicals generated by irradiating radiation such as ultraviolet rays or electron beams, and the resin is cured. Alternatively, a release agent having an epoxy group that causes a cationic polymerization reaction to be cured by a strong acid generated by ultraviolet light, heat, or the like can be given as an example.

Specific examples of these release agents include a mixed composition of a mercapto group-containing organopolysiloxane and a vinyl group-containing organopolysiloxane, an acrylic group, a methacryl group or a cinnamoyl group-containing organopolysiloxane composition, a maleimide group or Phenylmaleimide group-containing organopolysiloxane composition, azide group-containing organopolysiloxane and vinyl group-containing organopolysiloxane, thioacryl group, thiomethacryl group or thiocinnamoyl group-containing organopolysiloxane composition, acrylamide group, methacryl An amide group or cinnamoylamide group-containing organopolysiloxane composition, and the like. Also, an epoxy group-containing organopolysiloxane utilizing ultraviolet-initiated cationic polymerization, and a photodecomposition type initiator diazo Mixed composition of Umuruisu salt can also be used.

By using a solvent-free release agent as the release agent, coloring of the heat-sensitive recording layer by heating or coloring of the heat-sensitive recording layer by penetration of the solvent into the heat-sensitive recording layer, and without a drying step, Curling of the support can be suppressed. The viscosity of the resin is preferably about 10 to 10,000 cps in consideration of the impregnation of the resin into the heat-sensitive recording layer and the uniformity of the coated surface. In the release agent, other radiation-curable resins, photopolymerization initiators, crosslinking agents, dyes, pigments, wetting agents, defoamers, dispersants, antistatic agents, leveling agents, lubricants, etc., if necessary. The various auxiliary agents described above can be appropriately added within a range not to impair the desired effect.

The method of applying the release agent is not particularly limited, and ordinary application means such as a bar coater, a multi-stage roll coater, an air knife coater, a gravure coater, and an offset gravure coater are appropriately used. The coating amount of the release agent is in the range of 0.5 to 5.0 g / m ² , preferably 0.8 to 3.0 g / m ² .

The radiation used to cure the release agent in the present invention includes ultraviolet rays, electron beams and the like. Examples of the ultraviolet irradiation apparatus include low-pressure mercury lamps, medium-pressure mercury lamps, high-pressure mercury lamps, metal halide lamps and the like. There is also an ozone-less type with little ozone. Generally, a plurality of lamps having an output of 30 W / cm or more are often used in parallel.

As an electron beam irradiator, an electron beam accelerator having an acceleration voltage of 100 to 1000 kV, preferably 100 to 300 kV is used in terms of permeability and curability. It is desirable to adjust within the range of about 5 to 20 Mrad. If it is less than 0.5 Mrad, a sufficient irradiation effect cannot be obtained, and irradiation exceeding 20 Mrad is not preferable because it may deteriorate the base material. As an electron beam irradiation method, for example, a scanning method, a curtain beam method, a broad beam method, or the like is employed. In the electron beam irradiation step, a synthetic resin film, a metal layer, a metal drum, or the like can be closely attached to the protective layer, and the release agent layer can be cured while transferring its shape. During electron beam irradiation, if the oxygen concentration is high, the curing of the release agent is hindered, so that nitrogen, helium,
Irradiation is preferably performed in an atmosphere in which replacement with an inert gas such as carbon dioxide is performed and the oxygen concentration is controlled to 600 ppm or less, preferably 400 ppm or less.

According to the present invention, the release agent layer formed as described above has a dynamic friction coefficient between the release agent layer surfaces of 0.15 to 0.15.
By setting the ratio to 0.40, more preferably 0.20 to 0.35, an effect excellent in recording suitability and thermal head cleaning property can be obtained. If the coefficient of kinetic friction between the release agent layers is less than 0.15, the thermal head cleaning effect cannot be obtained, and if it is more than 0.40, sticking causes printing to shrink and an accurate recorded image cannot be obtained.

The coefficient of kinetic friction between the surfaces of the release agent layers is 0.15.
There is no particular limitation on the method for obtaining the composition of ~ 0.40, and the selection and adjustment of the amount of the release agent, the addition of an auxiliary such as a pigment and a crosslinking agent in the release agent layer and the adjustment of the amount of the release agent, It can be obtained by adjusting the coating amount of the release agent layer or the irradiation amount of the radiation, or adjusting the film hardness of the release agent layer as appropriate.

In the present invention, a heat-sensitive recording layer is provided on a support, but the heat-sensitive recording system to be applied is not particularly limited.
Examples thereof include a combination of a leuco dye and a color former, a combination of a diazonium salt and a coupler, a combination of a chelate compound of a transition element such as iron and a color former, and a combination of an aromatic isocyanate compound and an imino compound. Further, it is of course possible to use a plurality of recording methods in combination. Among them, a combination of a leuco dye and a color former is preferably used because of its excellent color density. Hereinafter, a thermal recording method using a leuco dye and a color former will be described.

Various known leuco dyes can be used, and specific examples thereof include the following. Dyes that give black color include 3-di (n-butylamino) -6-methyl-7-anilinofluoran, 3-di (n-pentylamino) -6-methyl-7-anilinofluoran, 3- (N-isoamyl-N-ethylamino)
-6-methyl-7-anilinofluoran, 3- (N-n
-Hexyl-N-ethylamino) -6-methyl-7-anilinofluoran, 3- [N- (3-ethoxypropyl) -N-ethylamino] -6-methyl-7-anilinofluoran, 3 -Di (n-butylamino) -7- (2-
Chloroanilino) fluoran, 3-diethylamino-7
-(2-chloroanilino) fluoran, 3-diethylamino-6-methyl-7-anilinofluoran, 3- (N
-Cyclohexyl-N-methylamino) -6-methyl-
7-anilinofluoran and the like.

Dyes giving a red, purple-red, or orange-colored color include 3,6-6-bis (diethylamino) fluoran-γ-anilinolactam and 3,6-bis (diethylamino) fluoran-γ- ( p-nitro) anilinolactam, 3,6-bis (diethylamino) fluoran-γ- (o-chloro) anilinolactam, 3-dimethylamino-7-bromofluoran, 3-diethylaminofluoran, 3-diethylamino- 6-methylfluoran, 3-diethylamino-7-methylfluoran,
3-diethylamino-7-chlorofluorane, 3-diethylamino-7-bromofluoran, 3-diethylamino-7,8-benzofluoran, 3-diethylamino-
6,8-dimethylfluoran, 3-diethylamino-6
-Methyl-7-chlorofluorane, 3-diethylamino-7-tert-butylfluoran, 3- (N-ethyl-N-tolylamino) -7-methylfluoran, 3-
(N-ethyl-N-tolylamino) -7-ethylfluoran, 3- (N-ethyl-N-isobutylamino) -6
-Methyl-7-chlorofluoran, 3- (N-ethyl-
N-isoamylamino) -7-phenoxyfluoran;
3- (N-ethyl-N-isoamylamino) -7,8-
Benzofluorane, 3-cyclohexylamino-6-chlorofluorane, 3-di-n-butylamino-6-methyl-7-bromofluorane, 3-di-n-butylamino-7,8-benzofluoran , 3-tolylamino-7-
Methylfluoran, 3-tolylamino-7-ethylfluoran, 3,3′-bis (1-n-butyl-2-methylindol-3-yl) phthalide, 3,3′-bis (1
-Ethyl-2-methylindol-3-yl) phthalide, 3,3'-bis (1-n-octyl-2-methylindol-3-yl) phthalide, 7- (N-ethyl-N
-Isoamylamino) -3-methyl-1-phenylspiro [(1,4-dihydrochromeno [2,3-c] pyrazole) -4,3'-phthalide], 7- (N-ethyl-N
-Isoamylamino) -3-methyl-1-p-methylphenylspiro [(1,4-dihydrochromeno [2,3-
c] pyrazole) -4,3'-phthalide], 7- (N-
Ethyl-Nn-hexylamino) -3-methyl-1-
Phenylspiro [(1,4-dihydrochromeno [2,3
-C] pyrazole) -4,3'-phthalide] and the like.

As the dye giving a blue color, 3,
3-bis (p-dimethylaminophenyl) -6-dimethylaminophthalide, 3- (4-diethylamino-2-methylphenyl) -3- (4-dimethylaminophenyl)
-6-dimethylaminophthalide, 3- (1-ethyl-2
-Methylindol-3-yl) -3- (4-diethylaminophenyl) phthalide, 3- (1-ethyl-2-methylindol-3-yl) -3- (2-methyl-4-
Diethylaminophenyl) -4-azaphthalide, 3-
(1-ethyl-2-methylindol-3-yl) -3
-(2-ethoxy-4-diethylaminophenyl) -4
-Azaphthalide, 3- (1-ethyl-2-methylindol-3-yl) -3- (2-n-hexyloxy-4
-Diethylaminophenyl) -4-azaphthalide, 3-
And diphenylamino-6-diphenylaminofluoran.

As the dye giving green color, 3
-(N-ethyl-NN-hexylamino) -7-anilinofluoran, 3-diethylamino-7-dibenzylaminofluoran, 3,3-bis (4-diethylamino-2-ethoxyphenyl) -4 -Azaphthalide, 3-
(N-ethyl-N-p-tolylamino) -7- (N-phenyl-N-methylamino) fluoran, 3- [p-
(P-anilinoanilino) anilino] -6-methyl-7
-Chlorofluorane, 3,6-bis (dimethylamino)
Fluorene-9-spiro-3 ′-(6′-dimethylamino) phthalide and the like.

Various materials are also known for the coloring agent used in combination with the leuco dye as described above, for example, 4-tert-butylphenol, 4-acetylphenol, 4-tert-octylphenol, 4,4 '.
-Sec-butylidene diphenol, 4-phenylphenol, 4,4'-dihydroxydiphenylmethane,
4,4'-isopropylidene diphenol, 4,4'-
Cyclohexylidene diphenol, 4,4'-dihydroxydiphenyl sulfide, 4,4'-thiobis (3
-Methyl-6-tert-butylphenol), 4,
4'-dihydroxydiphenylsulfone, 2,4'-dihydroxydiphenylsulfone, 4-hydroxy-4 '
-Isopropoxydiphenyl sulfone, bis (3-allyl-4-hydroxyphenyl) sulfone, 4-hydroxybenzophenone, 2,2'-bis [4- (4-hydroxyphenylsulfonyl) phenoxy] diethyl ether, 4,4'- Bis (Np-trisulfonylurea)
Diphenylmethane, Np-trisulfonyl-N′-phenylurea, dimethyl 4-hydroxyphthalate,
Methyl hydroxybenzoate, propyl 4-hydroxybenzoate, sec-butyl 4-hydroxybenzoate, 4
Phenolic compounds such as -phenyl benzoate, benzyl 4-hydroxybenzoate, tolyl 4-hydroxybenzoate, chlorophenyl 4-hydroxybenzoate, 4,4'-dihydroxydiphenyl ether, or benzoic acid, p-tert-butyl Benzoic acid, trichlorobenzoic acid, terephthalic acid, salicylic acid, 3-ter
t-butylsalicylic acid, 3-isopropylsalicylic acid,
3-benzylsalicylic acid, 3- (α-methylbenzyl)
Aromatic carboxylic acids such as salicylic acid, 3,5-di-tert-butylsalicylic acid, and these phenolic compounds, aromatic carboxylic acids and zinc, magnesium,
Organic acidic substances such as salts with polyvalent metals such as aluminum and calcium are exemplified. The color former is usually used in a proportion of 100 to 700 parts by weight, preferably 150 to 400 parts by weight, based on 100 parts by weight of the chromogenic dye.

The color-forming dyes and colorants used in the present invention are modified with polyacrylamide, polyvinylpyrrolidone, polyvinyl alcohol, and sulfone groups by using water as a dispersion medium and various wet mills such as a sand grinder, an attritor, a ball mill, and a coball mill. Modified polyvinyl alcohol such as polyvinyl alcohol, methylcellulose, carboxymethylcellulose, styrene-maleic anhydride copolymer salts and other water-soluble polymer compounds such as derivatives thereof, as well as a surfactant, an antifoaming agent and the like, and a dispersion liquid. After that, it is used for preparing a paint for the thermosensitive coloring layer. Further, after dissolving in a solvent, the mixture may be emulsified and dispersed in water together with the above-mentioned water-soluble polymer, and then the solvent may be evaporated to be used as a solid. In each case, the average particle diameter of the dispersion was 0.1.
2-3 μm is desirable.

The heat-sensitive recording layer may be added with a storability improver in consideration of the storability after printing, and various known materials such as a heat-soluble substance as a sensitizer for improving the sensitivity of the heat-sensitive recording paper. It is desirable to use a pulverizer having an average particle diameter of 0.2 to 3 μm as in the case of the above-described color-forming dye and color former.

In the present invention, a heat-sensitive recording layer which develops a different color tone under different heating conditions can be provided. The heat-sensitive recording layer is not particularly limited as long as a different color tone can be obtained by utilizing a difference in heating temperature or a difference in heat energy, but different coloring dyes are referred to as a high-temperature coloring layer and a low-temperature coloring layer. As described above, it can be roughly classified into a lamination type in which the chromogenic dye is contained in another layer and an identical layer type in which the other chromogenic dye is contained in the same layer by encapsulating one of the chromogenic dyes in a microcapsule. Although the present invention can be applied to both, the same layer type is preferable because the amount of heat at the time of high-temperature coloring can be set low. Further, a color-forming layer of three or more colors is also possible by combining these.

In the present invention, a water-soluble polymer having a film-forming property or a water-dispersible resin is used for the protective layer formed on the heat-sensitive recording layer as needed. Specific examples of such a water-soluble polymer or water-dispersible resin include, for example, starches, hydroxyethyl cellulose, methyl cellulose, carboxymethyl cellulose, gelatin, casein, gum arabic, fully saponified polyvinyl alcohol, partially saponified polyvinyl alcohol, carboxy-modified polyvinyl alcohol , Acetoacetyl group-modified polyvinyl alcohol, diisobutylene-maleic anhydride copolymer salt, styrene
Maleic anhydride copolymer salt, styrene-acrylic acid copolymer salt, ethylene-acrylic acid copolymer salt, urea resin,
Melamine resin, water-soluble polymer such as amide resin, styrene-butadiene copolymer latex, acrylic resin latex, polyester polyurethane ionomer,
Water-dispersible resins such as polyether polyurethane ionomers and the like can be mentioned. In addition, it is preferable to form a protective layer from the viewpoint of the storage stability of the thermal recording.

For the heat-sensitive recording layer and the protective layer, in addition to the above materials, various inorganic and organic pigments, adhesives, waxes, metal soaps, and the like can be used as appropriate. Various additives such as a dye, an oil repellent, an antifoaming agent, and a viscosity modifier can be used in a range that does not impair the desired effect.

The support in the present invention is not particularly limited. For example, high-quality paper (acid paper, neutral paper), medium paper, coated paper, art paper, glassine paper, resin laminated paper, synthetic paper (for example, polyolefin-based paper) ), A support such as synthetic fiber paper, nonwoven fabric, synthetic resin film and the like can be used.

Examples of the method for forming the heat-sensitive recording layer, the protective layer, and the like include an air knife coater, a variver blade coater, a pure blade coater, a rod blade coater, a short dwell coater, a curtain coater, a die coater, a gravure coater, a roll coater, and a sprayer. The coating is performed by various coating apparatuses such as a coater, a dip coater, and a bar coater.

The pressure-sensitive adhesive used in the present invention is not particularly limited.
Various pressure-sensitive adhesives such as a solvent-type pressure-sensitive adhesive, an emulsion-type pressure-sensitive adhesive, and a hot-melt-type pressure-sensitive adhesive can be used. In the case of the solvent type, it is desirable that the viscosity be in the range of 100 to 15,000 cps from the problem of controlling the amount of application in various application apparatuses. In the case of a hot melt type, the composition is heated and melted, and the viscosity at the time of coating is desirably in the range of 100 to 15,000 cps from the viewpoint of easy control of the coating amount. In the case of the emulsion type, the viscosity is preferably about 100 to 15,000 cps, and the solid content concentration is preferably 20 to 80% from the viewpoint of controlling the amount of application in various application apparatuses.

The coating amount of the pressure-sensitive adhesive of the present invention is 5% by dry weight.
~50g / m ² is preferred. More preferably, 10 to 30
g / m ² . Incidentally, if the coating amount is less than 5 g / m ² , sufficient adhesiveness cannot be obtained when used as a label, while if it exceeds 50 g / m ² , there is a problem that the adhesiveness is saturated and the economic efficiency is poor.

The method for applying the pressure-sensitive adhesive of the present invention to a support includes brush coating, spray coating, screen printing, gravure printing, offset printing, letterpress printing, Meyer bar coater, kiss roll coater, lip coater, and direct roll coater. This is performed by various coating apparatuses such as an offset roll coater, a gravure roll coater, a reverse roll coater, a rod coater, a blade coater, an air knife coater, and a slit die coater. If drying is necessary, it can be performed by a conventional method combined with the above-described apparatus for performing coating. In the drying, the drying is performed by appropriately adjusting the drying temperature so that the heat-sensitive recording layer provided on the support does not develop color. Also,
When curing by radiation is required, a radiation irradiation device similar to the ultraviolet irradiation device and the electron beam irradiation device used for curing the release agent can be appropriately used.

In the present invention, if necessary, an undercoat layer may be provided below the thermosensitive coloring layer for the purpose of improving the image quality and image density, or the purpose of preventing migration of the pressure-sensitive adhesive component into the support. To provide a barrier layer on the back side of the support (pressure-sensitive adhesive layer side), perforate the pressure-sensitive adhesive label, part-coat the pressure-sensitive adhesive except for the edges and perforations, and use the heat-sensitive recording layer Alternatively, various known techniques in the field of production of pressure-sensitive adhesive labels for heat-sensitive recording, such as coloring the release agent layer, can be added as necessary.

[0036]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, which, of course, are not intended to limit the scope of the present invention.
In the examples, parts and% are unless otherwise specified.
"Parts by weight" and "% by weight" are shown.

Example 1 [Production of thermal recording paper] "Preparation of coating liquid for undercoat layer" 100 parts of calcined clay (trade name: Ansilex, manufactured by EMC), 100 parts of a 10% aqueous solution of polyvinyl alcohol and 200 parts of water Was mixed and stirred to obtain a coating liquid for an undercoat layer.

Preparation of Solution A 40 parts of 3-di (n-butylamino) -6-methyl-7-anilinofluoran 5% aqueous solution of methylcellulose 40
Parts and 20 parts of water were pulverized with a sand mill until the average particle diameter became 0.8 μm.

Solution B Preparation of a composition comprising 40 parts of bis (3-allyl-4-hydroxyphenyl) sulfone, 40 parts of a 5% aqueous solution of methylcellulose, and 20 parts of water was carried out using a sand mill with an average particle size of 1.
Milled to 5 μm.

Preparation of Solution C 20 parts of di-p-methylbenzyl oxalate, di-oxalate
A composition comprising 20 parts of p-chlorobenzyl, 40 parts of a 5% aqueous solution of methylcellulose, and 20 parts of water was pulverized by a sand mill until the average particle diameter became 1 μm.

"Preparation of coating solution for thermosensitive coloring layer" 30 parts of solution A,
60 parts of the B liquid, 40 parts of the C liquid, 6 parts of amorphous silica (trade name: Mizukasil P-527, manufactured by Mizusawa Chemical Industry) and 10 parts of a 10% aqueous solution of polyvinyl alcohol are mixed and stirred to prepare a coating solution for the heat-sensitive coloring layer. Obtained.

[Preparation of Coating Solution for Protective Layer] 400 parts of a 10% acetoacetyl group-modified polyvinyl alcohol aqueous solution, 50 parts of kaolin (UW-90, manufactured by EMC), 10 parts of a 30% zinc stearate dispersion, and 100 parts of water Parts of the composition were mixed and stirred to obtain a coating liquid for a protective layer.

[Preparation of Thermal Recording Paper] On one side of a neutral paper-made high-quality paper having a basis weight of 60 g / m ² , the above-mentioned coating liquid for undercoat layer, coating liquid for thermosensitive recording and coating liquid for protective layer were dried. Is applied and dried so that the coating amount becomes 8 g / m ² , 5 g / m ² , and 3 g / m ² , respectively, to form an undercoat layer, a heat-sensitive recording layer, and a protective layer, and then to perform a smoothing treatment using a super calender. Then 2
A color thermal recording paper was obtained.

[Formation of Release Agent Layer] 100 parts of a UV-curable solventless silicone resin (BY24-551A, manufactured by Dow Corning Toray Silicone Co., Ltd.) and UV curable on the protective layer of the heat-sensitive recording paper using an offset gravure coater. Solventless silicone resin (BY24-551B,
A composition consisting of 30 parts of Dow Corning Toray Silicone Co., Ltd.) was mixed and stirred, applied so that the coating amount was 2.0 g / m ^2, and irradiated with an ultraviolet irradiation device (Rapid Cure, manufactured by Ushio Electric). Was cured by irradiating ultraviolet rays so as to be 100 mj / cm ² to obtain a thermosensitive recording paper having a release agent layer.

[Production of pressure-sensitive adhesive label] An acrylic emulsion pressure-sensitive adhesive (trade name: L-145K, manufactured by Nippon Carbide Industry Co., Ltd.) was applied to the back surface of the heat-sensitive recording paper having the release agent layer so that the dry weight was 20 g / m ^2. It was applied and dried with a reverse roll coater to form an adhesive layer, thereby producing an adhesive label for thermal recording.

Example 2 In "Formation of release agent layer" in Example 1, 70 parts of an ultraviolet-curable solventless silicone resin (POLY200, manufactured by Arakawa Chemical Industries), 70 parts of an ultraviolet-curable solventless silicone resin (RC
A250, Arakawa Chemical Industry Co., Ltd. (20 parts) and a UV-curable solvent-free silicone resin (RCA200, Arakawa Chemical Industry Co., Ltd.) 10 parts were mixed and stirred.
An adhesive label for heat-sensitive recording was obtained in the same manner as in Example 1 except that the coating was performed so as to be 0 g / m ² .

Example 3 In "Formation of a release agent layer" of Example 1, 100 parts of an ultraviolet-curable solventless silicone resin (BY24-551A, manufactured by Dow Corning Toray Silicone) and 100 parts of an ultraviolet-curable solventless silicone resin (BY24) -551B, manufactured by Dow Corning Toray Silicone Co., Ltd.) 30 parts and average particle size 2.
Thermal recording was performed in the same manner as in Example 1 except that a composition consisting of 10 parts of 0 μm silicone resin fine particles (KMP590, manufactured by Shin-Etsu Chemical Co., Ltd.) was mixed and stirred, and applied so that the coating amount was 1.5 g / m ^2. An adhesive label was obtained.

Comparative Example 1 An adhesive label for heat-sensitive recording was produced in the same manner as in Example 1 except that the amount of the release agent layer was changed to 0.5 g / m ^{2 in} “Formation of Release Agent Layer” of Example 1. did.

Comparative Example 2 In the "Formation of a release agent layer" in Example 1, 50 parts of an ultraviolet-curable solventless silicone resin (POLY200, manufactured by Arakawa Chemical Industries) and 50 parts of an ultraviolet-curable solventless silicone resin (RCA250, Arakawa Chemical Industries) (Commercially available) was mixed and stirred, and the adhesive label for heat-sensitive recording was produced in the same manner as in Example 1 except that the composition was applied so that the coating amount was 1.0 g / m ² .

Example 4 Two-color thermosensitive recording was carried out in the same manner as in Example 1 except that the preparation of a two-color thermosensitive coloring layer coating solution was carried out in the "Preparation of coating solution for thermosensitive coloring layer" in Example 1. Adhesive labels were manufactured.

Solution D Preparation 6 parts of 3-di (n-pentylamino) -6-methyl-7-anilinofluorane was dissolved in 24 parts of dicyclohexylmethane-4,4'-diisocyanate heated to 100 ° C. And 8% polyvinyl alcohol (trade name:
Gohsenol GM-14L, manufactured by Nippon Synthetic Chemical Industry Co., Ltd.) 250 parts of an aqueous solution was gradually added, and a homogenizer was used.
This was emulsified and dispersed by stirring at a rotation speed of 5,000 rpm, and 100 parts of water was added to the emulsified dispersion to make it uniform. The temperature of the emulsified dispersion was raised to 90 ° C., and a curing reaction was carried out for 10 hours to prepare a dispersion of black coloring dye-containing composite fine particles having an average particle diameter of 2.0 μm.

Preparation of Solution E 40 parts of 3- (N-ethyl-N-isoamyl) -7-phenoxyfluoran, 5% aqueous solution of methylcellulose 40
And a composition consisting of 20 parts of water and 20 parts of water, were pulverized with a sand mill until the average particle diameter became 1 μm to prepare a dispersion of a red coloring dye.

"Preparation of coating solution for two-color thermosensitive coloring layer" D solution 30
Part, E liquid 10 parts, B liquid 25 parts, C liquid 20 parts, amorphous silica (trade name: Mizukasil P-527, manufactured by Mizusawa Chemical Industry)
Six parts and 10 parts of a 10% aqueous solution of polyvinyl alcohol were mixed and stirred to obtain a two-color thermosensitive coloring layer coating liquid.

The following evaluations were performed on the heat-sensitive recording pressure-sensitive adhesive labels obtained in Examples and Comparative Examples, and the results are shown in Table 1.

[Coefficient of Dynamic Friction between Release Agent Layer Surfaces] The release agent layer surfaces of the obtained heat-sensitive recording pressure-sensitive adhesive label were measured according to JIS.
It was measured based on the horizontal method of P8147.

[Evaluation of Thermal Head Cleaning] Each of the obtained heat-sensitive recording adhesive labels was left in a room for 7 days.
ATAMAX linerless label printer PR
Using ODIGY PLUS, the heat-sensitive recording pressure-sensitive adhesive labels obtained in Examples 1 to 3 and Comparative Examples 1 and 2 were printed in black solid with a print length of 100 mm at a recording speed of 3 ips and an applied energy of 0.40 mj / dot. The obtained recorded image was measured in a visual mode using a Macbeth densitometer (RD-914, manufactured by Macbeth). The two-color heat-sensitive recording adhesive label obtained in Example 4 was subjected to black solid printing of 10 cm at an applied energy of 0.60 mj / dot.
The recording density was measured using a Macbeth densitometer red filter.

[Evaluation of Sticking] The print length of the recorded image obtained in the above [Evaluation of Thermal Head Cleaning] was measured, and shrinkage of the print due to sticking was evaluated.

[0058]

[Table 1]

[0059]

As described above, the pressure-sensitive adhesive label obtained by the present invention is a heat-sensitive recording pressure-sensitive adhesive label which does not require a release paper, and has excellent print running properties even at a high applied energy and has no printing trouble. This is an adhesive label for thermal recording that is excellent in heat resistance.

Claims (2)

[Claims] 1. A layer structure having a heat-sensitive recording layer on one side of a support, a release agent layer on the heat-sensitive recording layer and an adhesive layer on the other side, or a heat-sensitive recording layer on one side of the support. In a heat-sensitive recording pressure-sensitive adhesive label which does not require a release paper, having a protective layer on the heat-sensitive recording layer, a release agent layer on the protective layer, and a pressure-sensitive adhesive layer on the other surface, the release agent The layer is a layer obtained by curing a solventless release agent by irradiation with radiation, and has a dynamic friction coefficient (based on JIS P 8147) between the surfaces of the release agent layers of 0.15 to 0.40. Adhesive label for thermal recording. 2. The pressure-sensitive adhesive label for heat-sensitive recording according to claim 1, wherein the heat-sensitive recording layer develops at least two different color tones depending on the difference in the conditions for applying heat from the thermal head.