JPH1086537A - Thermal recording adhesive sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermal recording adhesive sheet adapted to high-speed issuing without decrease of color developing capacity of a thermal recording layer even under high temperature and high humidity conditions and adapted to distribution management utility with advantageous cost. SOLUTION: In the thermal recording adhesive sheet having a thermal recording layer, a barrier layer and a release layer sequentially provided on one surface side of a support and an adhesive layer provided on a rear surface side, the barrier layer contains aqueous resin obtained by seed polymerizing at least (meth)acrylamide as monomer or casein. Further, means containing 30wt.% or more of the resin obtained by seed polymerizing or casein to the whole solid amount in the barrier layer, and means for forming the release layer by emitting ultraviolet ray or electron beam to ultraviolet curable silicone compound or electron beam curable silicone compound to cure it are provided.

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 sheet, and more particularly to a heat-sensitive recording pressure-sensitive adhesive sheet suitable for distribution management.

[0002]

2. Description of the Related Art A thermosensitive recording medium in which a recording image is obtained by contacting a plurality of coloring substances with heat is well known.
As described above, the thermosensitive recording medium is relatively inexpensive, the recording apparatus is compact, and the maintenance thereof is easy. Therefore, the thermosensitive recording medium is used in recording media such as facsimile machines and various computers, and in a wide variety of fields. One of the fields of use is, for example, a heat-sensitive recording adhesive sheet or a heat-sensitive recording tag for a POS (point of sales) system.

Further, with the recent development of information processing technology and the performance of recording equipment, it has become possible to perform recording on a heat-sensitive recording adhesive sheet at a higher speed than before. Since a release paper is bonded for the purpose of protecting the agent layer, the diameter of the heat-sensitive recording pressure-sensitive adhesive sheet increases, and the size of the heat-sensitive recording pressure-sensitive adhesive sheet that can be loaded into a recording device is limited. The number of pressure-sensitive adhesive sheets that can be issued in one roll is reduced, and the recording pressure-sensitive adhesive sheet must be frequently replaced with a higher recording speed. In addition, the treatment of the release paper generated at this time is also a problem, and the cost of the release sheet in the recording adhesive sheet is not small in terms of cost.

A heat-sensitive recording pressure-sensitive adhesive sheet using no release paper is disclosed in JP-A-60-54842, JP-A-1-280584,
No. 2-165989, JP-A-5-8541 or JP-A-6-22
No. 2717 proposes this. However, the roll of the heat-sensitive recording pressure-sensitive adhesive sheet that does not use release paper has the surface of the heat-sensitive recording layer and the surface of the pressure-sensitive adhesive layer in contact with each other. There is a disadvantage that the coloring ability is lowered by penetrating into the heat-sensitive recording layer.

For this reason, there is a strong demand for a heat-sensitive recording pressure-sensitive adhesive sheet which can perform high-speed recording even under severe conditions such as distribution management use, does not lower the coloring ability, and is advantageous in terms of cost.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a distribution management system which has a small decrease in the coloring ability of the heat-sensitive recording layer even under high temperature and high humidity conditions, can be adapted to high-speed printing, and is advantageous in terms of cost. An object of the present invention is to provide a heat-sensitive recording pressure-sensitive adhesive sheet suitable for use.

[0007]

Means for Solving the Problems A heat-sensitive recording pressure-sensitive adhesive sheet in which a heat-sensitive recording layer, a barrier layer, and a release layer are sequentially provided on one side of a support and a pressure-sensitive adhesive layer is provided on the back side, solves the above problems. As one means for accomplishing this, the present invention includes an aqueous resin or casein obtained by subjecting at least (meth) acrylamide to seed polymerization in a barrier layer. Further, means for causing the aqueous resin or casein obtained by the seed polymerization to be contained in an amount of 30% by weight or more based on the total solid content in the barrier layer, and providing the release layer with an ultraviolet-curable silicone compound or an electron-beam-curable silicone compound. Alternatively, there is a means for forming by curing by irradiating an electron beam.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention is characterized in that at least (meth) acrylamide is seed-polymerized as a monomer in a barrier layer, and a specific aqueous resin or casein is obtained. Such a specific aqueous resin includes fine particles (50 to 300) previously emulsion-polymerized.
Ii), that is, by drying a latex obtained by polymerizing (meth) acrylamide as at least a monomer around the seed particles. Among them, casein is preferred because of its excellent adhesion to the release layer. Of course, a specific aqueous resin and casein can be used in combination.

The seed particles obtained by emulsion polymerization include, for example, (meth) acrylic ester, styrene-
(Meth) acrylate, (meth) acrylonitrile, styrene-butadiene, (meth) acrylonitrile-butadiene, (meth) acrylate-
Emulsions composed of hydrophobic polymers such as butadiene, vinyl chloride, and vinyl acetate can be used, and they can be used alone or in combination of two or more.

[0010] At least (meth) acrylamide is used as a monomer to be seed-polymerized around the seed particles. However, as long as the desired effect of the present invention is not impaired, copolymerization with (meth) acrylamide and the (meth) acrylamide is not required. Other possible monomers can also be used. Specific examples of such monomers include, for example, methyl (meth) acrylate,
Ethyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, (meth) acrylic acid 2 −
(Meth) acrylates such as aminoethyl, 2- (N-methylamino) ethyl (meth) acrylate, 2- (N, N-dimethylamino) ethyl (meth) acrylate, and glycidyl (meth) acrylate Vinyl esters such as vinyl acetate, vinyl propionate, etc .; monomers containing nitrile groups such as (meth) acrylonitrile; unsaturated carboxylic acids such as (meth) acrylic acid, maleic anhydride, fumaric acid, itaconic acid, crotonic acid, etc. Examples thereof include acids, aromatic vinyl monomers such as styrene, α-methylstyrene and divinylbenzene, and N-substituted unsaturated carboxylic amides such as N-methylol (meth) acrylamide. Above all,
Unsaturated monomers having a functional group such as a carboxyl group, a hydroxyl group, an amino group, a methylol group, and a glycidyl group are preferably used.

The amount of the (meth) acrylamide used in the present invention is 5 to 100 parts by weight of the solid content of the seed particles.
３００300 parts by weight, preferably 10-100 parts by weight. If the amount of acrylamide is less than 5 parts by weight, sufficient heat resistance and solvent resistance cannot be obtained, and if it exceeds 500 parts by weight, the water resistance decreases, and at the same time, the viscosity of the copolymer emulsion significantly increases. There is a possibility that a uniform coating surface cannot be obtained.

The content of the specific aqueous resin or casein in the barrier layer is not particularly limited, but is at least 30% by weight, preferably at least 50% by weight, based on the total solid content of the barrier layer. Furthermore, as long as the desired effects of the present invention are not impaired, various known aqueous resins can be used in combination, and specific examples of such resins include starches, hydroxyethyl cellulose, methyl cellulose, carboxymethyl cellulose, gelatin, gum arabic, Polyvinyl alcohol, carboxy-modified polyvinyl alcohol, acetoacetyl group-modified polyvinyl alcohol, silicon-modified polyvinyl alcohol, diisobutylene-maleic anhydride copolymer salt, styrene-maleic anhydride copolymer salt, ethylene-acrylic acid copolymer salt, Styrene-acrylic acid copolymer salts, styrene-butadiene-based latex, polyurethane-based latex, and the like are included.

In the heat-sensitive recording pressure-sensitive adhesive sheet of the present invention, a barrier layer containing a specific aqueous resin is provided on the heat-sensitive recording layer for the purpose of causing the pressure-sensitive adhesive layer to adversely affect the heat-sensitive recording layer or improving the recording suitability. In order to further improve the barrier property to the release layer and the adhesion between the barrier layer and the release layer, the average particle diameter in the barrier layer is 0.1 to 3 μm.
About 20 to 70% by weight of the total pigment in the barrier layer
It can also be contained. When the content of the pigment is less than 20% by weight, the effect of improving the adhesion between the barrier layer and the release layer is low, and when the content exceeds 70% by weight, the release agent penetrates into the barrier layer during the formation of the release layer, resulting in poor release properties. There is a possibility of lowering, and it is preferably about 25 to 50% by weight.

Specific examples of such pigments include calcium carbonate, zinc oxide, aluminum oxide, titanium dioxide, amorphous silica, aluminum hydroxide, barium sulfate, talc, kaolin, clay, urea-formalin resin filler, and nylon filler. No. Among them, kaolin and aluminum hydroxide are preferable because the barrier property against the release layer is extremely low, the adhesion between the barrier layer and the release layer is excellent, and the recording density is low.

In the present invention, a heat-sensitive recording layer, a barrier layer, and a release layer are sequentially provided on one side of the support, so that even if an adhesive layer is provided on the back side of the support, a roll-shaped heat-sensitive layer is unnecessary. An adhesive sheet for recording is obtained. Since at least the release layer is formed after providing the heat-sensitive recording layer, the release agent used in the release layer is cured by irradiating an ultraviolet curable silicone compound or an electron beam curable silicone compound with ultraviolet light or an electron beam. Silicone compounds are preferably used because heat curing is unnecessary.

Specific examples of the ultraviolet-curable silicone compound or the electron beam-curable silicone compound include, for example, a mixed composition of a mercapto group-containing organosiloxane and a vinyl group-containing organosiloxane, an acrylic group, a methacryl group or a cinnamoyl group-containing organosiloxane. A composition, a maleimide group or a phenylmaleimide group-containing organosiloxane composition, a mixed composition of an azide group-containing organosiloxane and a vinyl group-containing organosiloxane,
Examples thereof include an organosiloxane composition containing a thioacryl group, a thiomethacryl group or a thiocinnamoyl group, and an organosiloxane composition containing an acrylamide group, a methacrylamide group or a cinnamoylamide group. In the case of an ultraviolet curable silicone compound, a curing initiator is required. Specific examples of such a curing initiator include benzoyl alkyl ether and its derivatives, acetophenone and its derivatives, thioxanthone and its derivatives, and the like.

The amount of the electron beam for irradiating the electron beam-curable silicone compound with an electron beam to cure the release layer is from 0.1 to 0.1%.
15 Mrad, more preferably about 0.5 to 10 Mrad is desirable. If it is less than 0.1 Mrad, the resin component cannot be sufficiently cured. Excessive electron beam irradiation exceeding 15 Mrad may cause coloration or discoloration of the thermosensitive recording medium. May also cause a drop in paper strength. In addition, as an electron beam irradiation method, for example, a scanning method, a curtain beam method, a broad beam method, or the like can be employed.
KV is appropriate.

When the release layer is cured by irradiating the ultraviolet-curable silicone compound with ultraviolet rays, a curing initiator is added to the release layer coating liquid in an amount of 0.1 to the ultraviolet radiation-curable compound.
It is necessary to add about 10 to 10% by weight. Specific examples of such a curing initiator include benzoyl alkyl ether and its derivatives, acetophenone and its derivatives, thioxanthone and its derivatives, and the like.

Various known pressure-sensitive adhesives can be used for the pressure-sensitive adhesive layer. Specific examples of such pressure-sensitive adhesives include natural rubber, acrylic resin-based pressure-sensitive adhesives, styrene-isoprene-styrene block copolymer, and the like. Removable pressure-sensitive adhesives such as two-component crosslinkable acrylics are exemplified. In particular, the re-peelable pressure-sensitive adhesive is used in combination with an appropriate cross-linking agent such as an epoxy derivative, so that when the pressure-sensitive adhesive layer is formed on the back surface side of the support, the cross-linking of the pressure-sensitive adhesive does not progress,
To some extent, the pressure-sensitive adhesive soaks into the support, and a suitable adhesive strength to the support is obtained. In addition, as the crosslinking of the pressure-sensitive adhesive progresses with time, the cohesive force increases, and re-peelability occurs.

Examples of the thermal recording method to which the present invention is applied include a combination of a leuco dye and a color former, a combination of a diazonium salt and a coupler, a combination of a transition element such as iron and a chelate compound, and a combination of an aromatic isocyanate compound. A combination with an imino compound is exemplified, but a combination of a leuco dye and a color former is preferably used because of its excellent color density. Hereinafter, an adhesive sheet for a heat-sensitive recording layer using a leuco dye and a color former will be described in detail.

Various known dyes can be used as the leuco dye and the color former. Specific examples of leuco dyes include:
For example, the following are mentioned. 3,3-bis (p-dimethylaminophenyl) -6-dimethylaminophthalide, 3- (4-diethylamino-2-methylphenyl)
-3- (4-Dimethylaminophenyl) -6-dimethylaminophthalide, 3-cyclohexylamino-6-chlorofluoran, 3-diethylamino-7-chlorofluoran, 3- (N-ethyl-p-toluidino) -7-methylfluoran, 3-dimethylamino-6-methyl-7-
Anilinofluoran, 3-diethylamino-6-methyl-7-anilinofluoran, 3-di (n-butyl) amino-6-methyl-7-anilinofluoran, 3-di (n
-Pentyl) amino-6-methyl-7-anilinofluoran, 3- (N-ethyl-N-isoamyl) amino-6
-Methyl-7-anilinofluoran, 3- (N-methyl-N-cyclohexyl) amino-6-methyl-7-anilinofluoran, 3-diethylamino-7- (m-trifluoromethyl) anilinofur Oran, 3-diethylamino-7- (o-chloroanilino) fluoran, 3-diethylamino-7- (o-fluoroanilino) fluoran, 3-di (n-butyl) amino-7- (o-fluoroanilino) fluoran , 3- (n-ethyl-p-toluidino) -6-methyl-7-anilinofluoran, 3-pyrrolidino-6-methyl-7-anilinofluoran, 3-
Piperidino-6-methyl-7-anilinofluoran,
3,3-bis [1- (4-methoxyphenyl) -1-
(4-dimethylanilino) ethylene-2-yl] -4,
5,6,7-tetrachlorophthalide and the like.

Of course, the present invention is not limited to these leuco dyes, and two or more of them can be used in combination. The amount of these leuco dyes used is about 0.1 to 3 g / m ² .

Examples of the coloring agent include 4,4'-isopropylidenediphenol, 4,4'-cyclohexylidenediphenol, 2,2-bis (4-hydroxyphenyl) -4-methylpentane, 4-hydroxy Benzyl benzoate, 2,4′-dihydroxydiphenyl sulfone,
4,4′-dihydroxydiphenylsulfone, 4-hydroxy-4′-isopropoxydiphenylsulfone, bis (3-allyl-4-hydroxyphenyl) sulfone,
Methyl bis (p-hydroxyphenyl) acetate, 1,1-
Bis (4-hydroxyphenyl) -1phenylethane,
1,4-bis [α-methyl-α- (4′-hydroxyphenyl) ethyl] benzene, 1,3-bi [α-methyl-
α- (4′-hydroxyphenyl) ethyl] benzene,
Phenolic compounds such as di (4-hydroxy-3-methylphenyl) sulfide and 2,2′-thiobis (3-tert-octylphenol); thiourea compounds such as N, N′-di-m-chlorophenylthiourea; − (P−
Toluenesulfonyl) carbamoyl acid p-cumylphenyl ester, N- (p-toluenesulfonyl) carbamoyl acid p-benzyloxyphenyl ester, N- (o
-Toluoyl) -p-toluenesulfonamide, N- (p
- toluenesulfonyl) -N '- (p-tolyl) having a -SO ₂ NH- bond in the molecule, such as urea, p- chlorobenzoic acid zinc, 4- [2-(p-methoxyphenoxy) ethyloxy] salicylic acid Zinc, 4- [3- (p-
Tolylsulfonyl) propyloxy] zinc salicylate,
5- [p- (2-p-methoxyphenoxyethoxy) cumyl] zinc, an aromatic carboxylic acid such as zinc salicylate;

The ratio of the leuco dye to the colorant is appropriately selected according to the type of the leuco dye and the colorant used, and is not particularly limited. 1 to 10 parts by weight, preferably 1 to
About 5 parts by weight of a coloring agent is used.

In the heat-sensitive recording layer, a storability improving agent for further improving the storability of the recorded image or a sensitizer for increasing the recording sensitivity can be used. Specific examples of such a preservability improver include, for example, 1,1,3-tris (2-methyl-4
-Hydroxy-5-cyclohexylphenyl) butane,
1,1,3-tris (2-methyl-4-hydroxy-5
-Tert-butylphenyl) butane, 2,2'-methylenebis (4-methyl-6-tert-butylphenol),
2,2′-ethylidenebis (4,6-di-tert-butylphenol), 4,4′-thiobis (2-methyl-6-
tert-butylphenol), 4,4′-butylidenebis (6-tert-butyl-m-cresol), 4,4′-thiobis (3-methylphenol), 4,4′-dihydroxy-3,3 ′, 5 5'-tetrabromodiphenylsulfone, 4,4'-dihydroxy-3,3 ', 5,5'
-Tetramethyldiphenyl sulfone, 2,2-bis (4
Hindered phenol compounds such as -hydroxy-3,5-dimethylphenyl) propane, 1,4-diglycidyloxybenzene, 4,4'-diglycidyloxydiphenylsulfone, and 4-benzyloxy-4 '-(2-methyl Epoxy compounds such as glycidyloxy) diphenyl sulfone, diglycidyl terephthalate, cresol novolak type epoxy resin, phenol novolak type epoxy resin, bisphenol A type epoxy resin, and N, N'-
Di-2-naphthyl-p-phenylenediamine, 2,2 ′
-Methylenebis (4,6-di-tert-butylphenyl)
Sodium phosphate or polyvalent metal salt, bis (4
-Ethyleneiminocarbonylaminophenyl) methane and the like.

Specific examples of the sensitizer include, for example, stearic acid amide, ethylene bis stearic acid amide, methylene bis stearic acid amide, N-methylol stearic acid amide, dibenzyl terephthalate, 1-hydroxy-
Phenyl 2-naphthoate, 2-naphthylbenzyl ether, m-terphenyl, p-benzylbiphenyl, p-
Tolylbiphenyl ether, di (p-methoxyphenoxyethyl) ether, 1,2- (3-methylphenoxy) ethane, 1,2-di (4-methylphenoxy) ethane, 1,2-di (4-methoxyphenoxy) Ethane,
1,2-di (4-chlorophenoxy) ethane, 1,2-
Diphenoxyethane, 1- (4-methoxyphenoxy)
-2- (3-methylphenoxy) ethane, p-methylthiophenylbenzyl ether, 1,4-di (phenylthio) butane, p-acetotoluidide, p-acetophenethidide, N-acetoacetyl-p-toluidine, di ( β
-Biphenylethoxy) benzene, p-di (vinyloxyethoxy) benzene, 1-isopropylphenyl-2
-Phenylethane, di-p-chlorobenzyl oxalate, di-p-methylbenzyl oxalate, dibenzyl oxalate and the like. The use amount of these sensitizers is not particularly limited, but it is generally desirable to adjust the amount to 4 parts by weight or less per 1 part by weight of the color former.

The heat-sensitive recording layer generally uses water as a dispersion medium,
It is prepared by finely dispersing the leuco dye, color former, sensitizer, and preservative improver separately or separately with a stirring / pulverizer such as a ball mill, attritor, or sand mill, and then adding an adhesive, etc. The coating liquid for a heat-sensitive recording layer is applied to a support and dried to form a coating.

Specific examples of the adhesive include starches, hydroxyethyl cellulose, methyl cellulose,
Carboxymethyl cellulose, gelatin, casein, gum arabic, polyvinyl alcohol, carboxy-modified polyvinyl alcohol, acetoacetyl group-modified polyvinyl alcohol, silicon-modified polyvinyl alcohol, diisobutylene-maleic anhydride copolymer salt, styrene-maleic anhydride copolymer salt And ethylene-acrylic acid copolymer salt, styrene-acrylic acid copolymer salt, styrene-butadiene-based latex, polyester polyurethane-based latex, and acrylic latex. The amount of the adhesive used is 5 to 5% based on the total solid content of the heat-sensitive recording layer.
About 40% by weight is preferable.

Various auxiliaries can be added to the coating solution for the heat-sensitive recording layer, if necessary.
Pigment such as calcium carbonate, amorphous silica, zinc oxide, aluminum hydroxide, urea-formalin resin filler, sodium dioctyl sulfosuccinate, sodium dodecylbenzene sulfonate, sodium lauryl alcohol sulfate, sodium fatty acid metal salt, etc., stearin Lubricants such as zinc acid and calcium stearate, waxes such as polyethylene wax, carnauba wax, paraffin wax and ester wax, other antifoaming agents, coloring dyes and the like are appropriately added.

The method for forming the heat-sensitive recording layer and the barrier layer is not particularly limited, and may be, for example, an air knife coating, a variver blade coating, a pure blade cornering, a rod blade coating, a short dwell coating, a curtain coating, a die coating or the like. After the coating liquid for the heat-sensitive recording layer is coated on the support by a suitable coating method and dried, the coating liquid for the barrier layer is further coated and dried on the heat-sensitive recording layer. The support is appropriately selected from paper (neutral paper, acidic paper), plastic film, synthetic paper, nonwoven fabric, metal deposit, and the like. The coating amount of the heat-sensitive recording layer coating solution is ² to 12 g / m ² , preferably 3 to 12 g in dry weight.
10 g / m ² approximately, the coating amount of the barrier layer coating solution 0.5 to 15 g / m ² by dry weight, preferably 1.0~8g / m ²
It is about.

The method for forming the release layer and the pressure-sensitive adhesive layer is not particularly limited, and examples thereof include the same methods as those for forming the heat-sensitive recording layer and the barrier layer. Peeling the coating amount of the layer coating solution 0.1-5 g / m ² in solid weight, preferably 0.5 to 3 g / m ² approximately, 3 to 50 g / m ² coating amount of the adhesive layer by dry weight, Preferably it is about 5 to 30 g / m ² . As for the method of forming the pressure-sensitive adhesive layer, a method of directly forming the pressure-sensitive adhesive layer on the back side of the support, or forming the pressure-sensitive adhesive layer on the release layer, winding and transferring to the back side of the support. There is a way.

It is also possible to apply a smoothing treatment such as super calendering after the application of each layer, but it is particularly preferable to smooth the surface of the barrier layer to which the release layer is applied.
It is preferable for obtaining a smooth release layer. It is desirable that the surface of the barrier layer has a tack smoothness of 500 seconds or more. Also,
If necessary, a barrier layer may be provided between the support and the pressure-sensitive adhesive layer to further enhance the preservability and impart a strong gloss. Furthermore, an intermediate layer containing an organic or inorganic oil-absorbing pigment as a main component is provided between the support and the heat-sensitive recording layer, a perforation is formed in the pressure-sensitive adhesive sheet, or the pressure-sensitive adhesive is printed by an edge portion or a perforation. Various other known techniques in the field of heat-sensitive recording medium production, such as part coating except for parts, can be added as necessary.

[0033]

The present invention will be described in more detail with reference to the following Examples, but it should be understood that the present invention is by no means restricted to such specific Examples. Parts and% in Examples are parts by weight and% by weight, respectively, unless otherwise specified.

Example 1 Formation of Intermediate Layer 100 parts of calcined clay (trade name: Ansilex, manufactured by EMC, oil absorption 110 ml / 100 g), 1 part of a 40% aqueous solution of sodium polyacrylate, styrene having a solid concentration of 48% A composition comprising 14 parts of a butadiene latex, 50 parts of a 10% aqueous solution of polyvinyl alcohol and 100 parts of water was mixed and stirred to obtain 64 g /
m ² neutral paper was coated and dried on one side of the neutral paper so that the coating amount after drying was 9 g / m ² to form an intermediate layer.

Preparation of Solution A 10 parts of 3-di (n-butyl) amino-6-methyl-7-anilinofluoran, 5% aqueous solution of methylcellulose 5
Parts and 40 parts of water were pulverized with a sand mill until the average particle size became 1.0 μm.

Preparation of Solution B A composition comprising 30 parts of 4-hydroxy-4'-isopropoxydiphenylsulfone, 5 parts of a 5% aqueous solution of methylcellulose and 80 parts of water was pulverized by a sand mill until the average particle diameter became 1.0 μm. .

Solution C Preparation A composition comprising 20 parts of 1,2-di (3-methylphenoxy) ethane, 5 parts of a 5% aqueous solution of methylcellulose and 55 parts of water is pulverized by a sand mill until the average particle diameter becomes 1.0 μm. did.

Formation of a heat-sensitive recording layer. Heat sensitivity obtained by mixing and stirring 55 parts of liquid A, 115 parts of liquid B, 80 parts of liquid C, 160 parts of a 10% aqueous solution of polyvinyl alcohol, 20 parts of a styrene-butadiene latex having a solid concentration of 48%, and 17 parts of light calcium carbonate. The coating liquid for a recording layer was applied and dried on the intermediate layer so that the coating amount after drying was 6 g / m ² to form a heat-sensitive recording layer.

Formation of barrier layer 50 parts of styrene, 2-ethylhexyl acrylate 43
Parts, a 50% solid concentration seed particle emulsion obtained by emulsion polymerization of a composition consisting of 5 parts of 2-hydroxyethyl methacrylate and 2 parts of acrylic acid, and acrylamide as a monomer component. Solid concentration of 3 obtained by copolymerizing 25 parts and 25 parts of methacrylamide
A coating solution for a barrier layer comprising 500 parts of a 0% aqueous resin was applied onto the heat-sensitive recording layer so as to have an applied amount of 4 g / m ² after drying, followed by surface smoothing treatment using a super calender, and barrier. A layer was formed. Note that the barrier smoothness of the barrier layer surface was 3000 seconds.

Formation of release layer Solvent-free ultraviolet-curable silicone [a mixed composition comprising 30 parts by weight of 1.5 mol% of a mercapto group-containing organosiloxane and 70 parts of 1.5 mol% of a vinyl group-containing organosiloxane, Shin-Etsu Chemical Co., Ltd. 100 parts and 3 parts of a curing initiator (acetophenone) were mixed and stirred, and a coating solution for a release layer obtained by applying and coating on the barrier layer so that the coating amount was 1.0 g / m ² , To form a release layer.

Formation of Pressure-Sensitive Adhesive Layer An acrylic resin-based pressure-sensitive adhesive emulsion was coated on the back side of the support and dried so that the coated amount after drying was 20 g / m ² . A sticky sort was obtained.

Example 2 In the formation of the barrier layer of Example 1, 50 parts of styrene, 43 parts of 2-ethylhexyl acrylate, and 2 parts of methacrylic acid were used.
-Around a seed particle of a seed particle emulsion having a solid concentration of 50% obtained by emulsion polymerization of a composition comprising 5 parts of hydroxyethyl and 2 parts of acrylic acid, 25 parts of acrylamide and methacrylamide 2 as monomer components.
Aqueous resin 500 having a solid concentration of 30% copolymerized with 5 parts
Parts, instead of 50 parts, seed emulsion particles obtained by emulsion polymerization of a composition comprising 48 parts of methyl methacrylate, 48 parts of butyl acrylate, 2 parts of 2-hydroxyethyl methacrylate and 2 parts of methacrylic acid. A heat-sensitive recording pressure-sensitive adhesive sheet was obtained in the same manner as in Example 1, except that around the seed particles of the emulsion, 500 parts of an aqueous resin having a solid concentration of 30% obtained by polymerizing 200 parts of acrylamide as a monomer component were further used. Was.

Example 3 In the formation of the barrier layer of Example 1, kaolin having a solid concentration of 50% (oil absorption of 50 ml / 100 g) was further dispersed in a barrier layer coating solution comprising 500 parts of an aqueous resin having a solid concentration of 30%. A heat-sensitive recording pressure-sensitive adhesive sheet was obtained in the same manner as in Example 1, except that 600 parts of the liquid was mixed and added. The barrier smoothness of the barrier layer surface was 1200 seconds.

Example 4 In the formation of the barrier layer of Example 1, a 50% solid concentration of aluminum hydroxide (oil absorption 43 ml / 10%) was further added to a barrier layer coating solution comprising 500 parts of an aqueous resin having a solid concentration of 30%.
0g) Except that 600 parts of the dispersion was added with mixing and stirring.
In the same manner as in Example 1, a heat-sensitive recording pressure-sensitive adhesive sheet was obtained. The barrier smoothness of the barrier layer surface was 1500 seconds.

Example 5 In the formation of the barrier layer of Example 1, a 50% solid concentration of aluminum hydroxide (oil absorption 43 ml / 10%) was further added to a barrier layer coating solution comprising 500 parts of an aqueous resin having a solid concentration of 30%.
0g) Except that 900 parts of the dispersion was mixed and added.
In the same manner as in Example 1, a heat-sensitive recording pressure-sensitive adhesive sheet was obtained. The barrier smoothness of the barrier layer surface was 1500 seconds.

Example 6 In the formation of the barrier layer of Example 1, an epoxy polyamide resin [trade name: Euramine P-560] was further added to a barrier layer coating solution composed of 500 parts of an aqueous resin having a solid concentration of 30%.
0, solid content 30%, manufactured by Mitsui Toatsu Chemicals, Inc.] was mixed and stirred to obtain a heat-sensitive recording pressure-sensitive adhesive sheet in the same manner as in Example 1. The barrier smoothness of the barrier layer surface was 3100 seconds.

Example 7 In the formation of the barrier layer of Example 1, a 15% aqueous solution of casein dissolved in ammonia was used instead of the barrier layer coating solution consisting of 500 parts of an aqueous resin having a solid concentration of 30%.
A heat-sensitive recording pressure-sensitive adhesive sheet was obtained in the same manner as in Example 1, except that the coating solution for barrier layer consisting of 0 parts was used. The barrier smoothness of the barrier layer surface was 1900 seconds.

Example 8 In the formation of the barrier layer of Example 1, a 15% aqueous solution of casein dissolved in ammonia was used instead of the barrier layer coating solution consisting of 500 parts of an aqueous resin having a solid concentration of 30%.
In 0 parts, kaolin with a solid concentration of 50% (oil absorption 50
ml / 100 g) A heat-sensitive recording pressure-sensitive adhesive sheet was obtained in the same manner as in Example 1, except that 600 parts of the dispersion was mixed, stirred and added, and a coating liquid for a barrier layer was used. The barrier smoothness of the barrier layer surface was 1900 seconds.

Example 9 A heat-sensitive recording pressure-sensitive adhesive sheet was obtained in the same manner as in Example 1, except that the release layer was formed as described below. Formation of a release layer Solvent-free electron beam-curable silicone compound [a mixed composition comprising 30 parts by weight of 1.5 mol% of a mercapto group-containing organosiloxane and 70 parts of 1.5 mol% of a vinyl group-containing organosiloxane, manufactured by Shin-Etsu Chemical Co., Ltd. Was applied onto the barrier layer so as to have a coating amount of 1.0 g / m ^2, and then irradiated with an electron beam to form a release layer.

Comparative Example 1 An adhesive sheet for heat-sensitive recording was obtained in the same manner as in Example 1 except that no barrier layer was provided.

Comparative Example 2 In the formation of the barrier layer of Example 1, a completely saponified polyvinyl alcohol [trade name: PVA110;
A pressure-sensitive adhesive sheet for thermal recording was obtained in the same manner as in Example 1 except that a 20% aqueous solution of Kuraray Co., Ltd. was used.

Comparative Example 3 In the formation of the barrier layer of Example 1, a 15% aqueous solution of a copolymer of acrylic acid and acrylamide was used instead of the barrier layer coating solution composed of 500 parts of an aqueous resin having a solid concentration of 30%. A heat-sensitive recording pressure-sensitive adhesive sheet was obtained in the same manner as in Example 1 except for using the same.

The following evaluation test was performed on the thus obtained pressure-sensitive adhesive sheet for heat-sensitive recording, and the results are shown in Table 1. [Coloring property] Each heat-sensitive recording pressure-sensitive adhesive sheet was colored at an applied energy of 0.5 mJ / dot using a thermo-evaluator (trade name: TH-PMD, manufactured by Okura Electric Co., Ltd.), and the color density of the obtained recorded image was measured. Is a Macbeth densitometer [trade name: RD-914]
Type, manufactured by Macbeth Corporation] in the visual mode.

[Coloring property after standing under high temperature and high humidity conditions] Rolls of the obtained heat-sensitive recording pressure-sensitive adhesive sheets were placed at 50 ° C and 95% R.
After leaving under the condition of H for 3 days, the color was developed in the same manner as in the above-described color development, and the color density of the obtained recorded image was measured.

[Adhesive force between release layer and pressure-sensitive adhesive layer] Each of the obtained heat-sensitive recording pressure-sensitive adhesive sheets was formed into a strip having a width of 5 cm and a length of 10 cm.
After applying pressure at a weight / cm ² , the adhesive strength was measured according to the 180 ° peeling method described in JISZ0237.

[Adhesion between Barrier Layer and Release Layer] The release layer surface of each of the obtained heat-sensitive recording pressure-sensitive adhesive sheets was rubbed with a fingertip, and the adhesion between the barrier layer and the release layer was visually evaluated. Evaluation criteria ★: The release layer surface does not peel off at all, and the release layer surface does not fog at all ◎: The release layer surface does not peel off, and the release layer surface hardly fogs. ：: The release layer surface is not peeled, but the release layer surface is slightly clouded. Δ: The release layer surface is not peeled off, but the release layer surface is considerably clouded. ×: The release layer surface is peeled off.

[0057]

[Table 1]

[0058]

As is clear from Table 1, the pressure-sensitive adhesive sheet for heat-sensitive recording of the present invention has a small decrease in color-forming ability even under high temperature and high humidity conditions, and does not require any treatment of a release paper after recording. It was suitable for distribution management use.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI C09J 7/02 JJN C09J 7/02 JKV JKV JKZ JKZ JLE JLE B41M 5/18 E D21H 27/00 B 101E D21H 5/00 B

Claims (3)

[Claims] 1. A heat-sensitive recording layer, a barrier layer,
In a heat-sensitive recording pressure-sensitive adhesive sheet having a release layer sequentially provided and a pressure-sensitive adhesive layer provided on the back side, an aqueous resin or casein obtained by subjecting at least (meth) acrylamide as a monomer to seed polymerization in a barrier layer. An adhesive sheet for heat-sensitive recording, characterized in that it is contained. 2. The heat-sensitive recording pressure-sensitive adhesive sheet according to claim 1, wherein the aqueous resin or casein obtained by the seed polymerization is contained in an amount of 30% by weight or more based on the total solid content in the barrier layer. 3. The release layer according to claim 1, wherein the release layer is a release layer cured by irradiating an ultraviolet ray-curable silicone compound or an electron beam-curable silicone compound with ultraviolet rays or an electron beam.
The pressure-sensitive adhesive sheet for heat-sensitive recording according to the above.