JP4601045B2 - Thermal adhesive label, thermal activation method for the label, and thermal adhesive label manufacturing method - Google Patents

Description

  The present invention relates to a heat-adhesive label that does not require a release paper, and in particular, a heat-adhesive label that does not require a release paper that develops adhesiveness by heat, a method for thermally activating the heat-adhesive label, and the heat-adhesive label It relates to the manufacturing method.

  In recent years, a label for thermal recording having adhesiveness has been used in a wide range of fields such as the POS field, but this label generally has a release paper pasted on a pressure-sensitive adhesive layer. . However, although such a thermal recording label having adhesiveness is useful, it has many disadvantages. That is, the release paper is peeled off when the label is attached to the article, and is discarded. This is a waste of resources and a waste of space for the wound body, and thus leads to high cost. Also, when a label is attached to an article, the work of peeling the release paper is troublesome.

In order to solve these problems, several heat-sensitive recording labels having an adhesive property that do not use release paper have been proposed.
Japanese Patent Application Laid-Open No. 2000-96015 (Patent Document 1) proposes a hot-melt type pressure-sensitive adhesive, but the hot-melt type pressure-sensitive adhesive has adhesiveness when heated, but solidifies immediately upon cooling. The delay property is short, and it is difficult to use like a normal pressure-sensitive label by heating in a short time such as a thermal head.
Japanese Utility Model Laid-Open No. 59-43979 (Patent Document 2), Japanese Utility Model Laid-Open No. 59-46265 (Patent Document 3), Japanese Utility Model Laid-Open No. 60-54842 (Patent Document 4), and the like include a microcapsule. Linerless thermal recording labels, such as those that have been made, and those that are provided with a release layer for the adhesive on the protective layer provided on the thermal recording layer to isolate the protective layer during winding (blocking or sealing) Proposed. However, these heat-sensitive recording labels that do not use release paper have problems such as weak adhesive strength and inability to print on the surface of the heat-sensitive recording layer, and have not been put into practical use.

  In addition, a method using a heat-sensitive adhesive (thermal adhesive) as a functional adhesive is proposed in JP-A-63-303387 (Patent Document 5) and JP-B-5-11573 (Patent Document 6). However, this is inferior in tackiness to the current thermal recording label. In addition, the heat-sensitive adhesive obtained by these methods has relatively good adhesion to paper, PET film, etc., but PVC wrap (PVC wrap) and polyethylene wrap (PE wrap) used in the food POS field. The adhesive strength to the adherend and the corrugated cardboard used for logistics is weak and has not reached the practical level.

Furthermore, as for a mere heat-adhesive label having no thermosensitive recording layer, Japanese Patent Application Laid-Open No. 63-152686 (Patent Document 7), Japanese Patent Application Laid-Open No. 6-57226 (Patent Document 8) and Japanese Patent Application Laid-Open No. 6-57233 are disclosed. It is disclosed in the gazette (patent document 9) etc. On the contrary, this heat-adhesive label uses a material having high adhesiveness when heated. Therefore, even during winding storage, the adhesiveness is partially developed depending on the storage temperature, and the front and back surfaces stick to each other and blocking occurs.
In order to prevent this blocking, it is necessary to control the adhesiveness, and in order to solve this, it has been proposed to use an appropriate resin for the adhesive in order to achieve both adhesive strength and blocking resistance. However, the adhesive strength and blocking resistance have not yet been achieved at the same time, and if blocking is prevented, the adhesive properties will eventually weaken. Adhesive strength and resistance to adherends such as PVC wrap, polyethylene wrap and cardboard will be reduced. In fact, a heat-adhesive label that achieves both blocking properties has not yet been developed as a simple label or a thermal recording label.

  Furthermore, as a technique for making this adhesive force and blocking property compatible, JP-A-8-41431 (Patent Document 10) and JP-A-2001-66991 (Patent Document 11) disclose a solid plasticizer layer on an adhesive layer. A pressure-sensitive adhesive material provided with is proposed. This label has problems such as insufficient adhesion to the corrugated cardboard, crystallization of the solid plasticizer over time, a decrease in adhesive strength over time, and insufficient sealing layer function and blocking.

Japanese Patent Application Laid-Open No. 9-20079 (Patent Document 12) discloses a thermal recording label in which a barrier layer that is activated by heat and exhibits adhesiveness is provided on a pressure-sensitive adhesive layer for the purpose of preventing blocking during winding. It is disclosed. In this label, the adhesiveness is sufficiently strong because of the pressure-sensitive adhesive, and the barrier layer itself exhibits adhesiveness when heat is applied, but the adhesiveness is strong, but specifically, the barrier layer contains a solid plasticizer at room temperature. The function of the layer is not sufficient and blocking occurs. Therefore, in order to satisfy the blocking resistance, it is necessary to increase the thickness of the barrier layer. However, in that case, the adhesiveness when heat is applied becomes insufficient, and the adhesive force to PVC wrap, polyethylene wrap and cardboard becomes insufficient. It is difficult to achieve both blocking resistance and adhesive strength. Furthermore, the solid plasticizer contained in the barrier layer has a problem that crystallization occurs over time and the adhesive strength decreases. In particular, the decrease in adhesive strength to cardboard is remarkable.
Japanese Patent Application Laid-Open No. 11-279495 (Patent Document 13) discloses a heat-sensitive adhesive sheet in which a thermoplastic resin is laminated on a heat-sensitive adhesive layer from a solid plasticizer and a thermoplastic resin. This is because the heat-sensitive adhesive layer contains a solid plasticizer, so the adhesion to cardboard is insufficient, and the solid plasticizer crystallizes over time, and the adhesive strength decreases over time. There is.

JP 2000-96015 A Japanese Utility Model Publication No.59-43979 Japanese Utility Model Publication No.59-46265 Japanese Utility Model Publication No. 60-54842 JP-A 63-303387 Japanese Utility Model Publication No. 5-11573 Japanese Unexamined Patent Publication No. 63-152686 JP-A-6-57226 JP-A-6-57233 JP-A-8-41431 JP 2001-66991 A JP-A-9-20079 JP-A-11-279495

The object of the present invention is to provide a pressure sensitive adhesive layer and a seal layer (shielding layer) on one side of the support or to further support it in view of the current state of the above-mentioned thermal recording labels or simple thermal adhesive labels. In a linerless label having a heat-sensitive recording layer on the other side of the body, the adhesive strength to each adherend, particularly the adhesive strength to cardboard is strong, the delay time is long, and the anti-blocking property is good (Including a thermoadhesive label for thermal recording).
Moreover, the objective of this invention is providing the thermal activation method of the said thermoadhesive label, and the manufacturing method of this thermoadhesive label.

That is, the said subject is solved by (1)-(5) of this invention.
(1) “A heat-adhesive label in which a pressure-sensitive adhesive layer is provided on a support and a seal layer is provided on the pressure-sensitive adhesive layer, and the seal layer comprises only a hot melt resin. The hot melt resin is at least one selected from an olefin / acrylic copolymer, an ethylene / vinyl acetate copolymer, and an olefin copolymer, and has a dry adhesion amount of 1.8 to 4.3 g / a heat-adhesive label characterized in that it is m ² ;
(2) “The adhesive amount of the sealing layer is ² to 4 g / m ² ,” (Thermo-adhesive label according to (1), wherein
(3) “Thermoadhesive label according to (1) or (2) above, wherein a thermosensitive recording layer is provided on the surface of the support opposite to the pressure-sensitive adhesive layer”;
(4) “Thermal activation method for a heat-adhesive label according to any one of (1) to (3) above, wherein the method is heated with a thermal head”;
(5) “Thermal adhesion according to any one of (1) to (3) above , wherein a seal layer is provided on the pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet provided with the pressure-sensitive adhesive layer on the support. A method for producing an adhesive label, wherein a sealing layer made of only the hot melt resin is formed by coating and drying an emulsion liquid of a hot melt resin.

The heat-adhesive label of the present invention is provided on a corrugated cardboard and a wrap film by providing a pressure-sensitive adhesive layer on a support and further providing a seal layer made of a hot-melt resin on the pressure-sensitive adhesive layer. It is a heat-adhesive label having strong adhesion to the surface and excellent blocking resistance.
In addition, the thermal activation method for the thermoadhesive label of the present invention is an excellent method with a small apparatus used for it and low power consumption, and the method for producing the thermoadhesive label of the present invention is an excellent label. It is also excellent in work efficiency and suitable for the production of a thermoadhesive label for thermal recording.

Hereinafter, the present invention will be described in more detail.
The heat-adhesive label of the present invention is formed by sequentially laminating a pressure-sensitive adhesive layer and a seal layer (shielding layer) on a support, but the seal layer is formed by applying a hot melt resin. When not heated, blocking can be prevented. Moreover, since the adhesiveness is exhibited at the time of heating, the adhesive strength is not reduced, and the adhesive strength to cardboard, vinyl chloride wrap and polyethylene wrap is sufficient. In addition, since the pressure-sensitive adhesive layer does not exhibit adhesiveness during storage, it can be printed on the heat-sensitive recording layer.

  The heat-sensitive adhesive label for heat-sensitive recording of the present invention is provided with a heat-sensitive recording layer mainly composed of a colorless or light leuco dye and a developer on the surface of a support, and on the other hand, a pressure-sensitive adhesive on the back surface of the support. It does not have a release paper on which a layer and the sealing layer are sequentially provided.

In the heat-activatable pressure-sensitive adhesive sheet of the present invention, the heating means for expressing the pressure-sensitive adhesiveness of the heat-active pressure-sensitive adhesive layer is not particularly limited, and known ones such as a hot plate, hot air, infrared rays, a heating roll, and a thermal head can be used. It is.
However, the thermal head can control heat generation on demand and perform thermal activation simultaneously with energization, thus reducing energy consumption and efficiently transferring heat to the heat-sensitive adhesive layer. This is particularly effective because it has the advantage that it can be thermally activated even if it is moved at a distance. Furthermore, among thermal heads, if the heat generating part is provided on the near edge, corner edge, or end face, the components constituting the thermally activated heat-sensitive adhesive layer are difficult to transfer to the thermal head, which is particularly effective. It is.
The heat-activatable pressure-sensitive adhesive sheet is used by being attached to an adherend after the heat-activatable pressure-sensitive adhesive layer is heated by such a heating means to develop adhesiveness.

  In the present invention, in particular, the adhesive strength against polyvinyl chloride wrap, polyethylene wrap, etc. is strong, and usually there is no surface stickiness due to the seal layer, so that the blocking resistance can be improved, the blocking resistance is not too strong, and further for thermal recording. In the case of a thermoadhesive label, the surface of the heat-sensitive recording layer is excellent in printability because there is no conventional silicon processing for blocking resistance.

As the pressure-sensitive adhesive used in the pressure-sensitive adhesive layer in the present invention, various pressure-sensitive adhesives used in this field can be appropriately used. Specific examples include polyvinyl acetate, vinyl acetate / ethylene copolymer, vinyl acetate / acrylic acid ester copolymer, vinyl acetate / maleic acid ester copolymer, ethylene / acrylic acid copolymer, epoxy resin, phenol Examples include emulsions such as resins, starch, gelatin, casein, polyvinyl alcohol, carboxycellulose, cellulose derivatives such as methylcellulose and hydroxyethylcellulose, and water-soluble resins such as polyvinylpyrrolidone, but the present invention is not limited thereto. Absent.
The application amount of the pressure sensitive adhesive is preferably 5 to 35 g / m ² , more preferably 10 to 25 g / m ² on a dry basis.

Examples of the hot melt resin contained in the seal layer in the present invention include olefin / acrylic copolymers such as polyethylene and polypropylene, ethylene / vinyl acetate copolymers, and olefin copolymers such as polyethylene and polypropylene.
If necessary, additives such as a tackifier can be added to the hot melt resin of the seal layer of the present invention.
The adhesion amount of the hot melt resin of the seal layer of the present invention is desirably ² to 4 g / m ² . If the adhesion amount is smaller than this, the pressure-sensitive adhesive is not sufficiently sealed, and there is a problem of blocking. On the other hand, when the adhesion amount is larger than this, there is a problem that the seal layer is not sufficiently collapsed when the seal layer is heated, and sufficient adhesive force cannot be obtained.

As a manufacturing method of the thermoadhesive label of this invention, the emulsion liquid which disperse | distributed hot-melt resin in water can be used by carrying out gravure coating drying. Of course, conventionally known hot melt coating can also be used, but in hot melt coating, it is necessary to heat and apply, and if a thermal recording layer is provided on the back side, the thermal recording layer will develop color. Caution must be taken.
As a method for activating the pressure-sensitive adhesive label of the present invention, a conventionally known thermal head, hot air, hot roller or the like can be used. In particular, the activation method using a thermal head has the advantage that the apparatus is small and consumes less power.

  The leuco dyes (color formers) used in the heat-sensitive recording layer of the heat-adhesive label for heat-sensitive recording of the present invention are applied singly or in combination of two or more. As such leuco dyes, this kind of heat-sensitive recording is used. Although the following applied to the material is arbitrarily used, it is not limited to this. For example, leuco compounds such as triphenylmethane, fluorane, phenothiazine, auramine, spiropyran, and indinophthalide are preferably used. Specific examples of such leuco dyes include those shown below.

  3,3-bis (p-dimethylaminophenyl) -phthalide, 3,3-bis (p-dimethylaminophenyl) -6-dimethylamine phthalide (also known as crystal violet lactone), 3,3-bis (p- Dimethylaminophenyl) -6-diethylaminophthalide, 3,3-3-3-bis (p-diethylaminophenyl) -6-chlorophthalide, 3,3-bis (p-dibutylaminophenyl) phthalide, 3-cyclohexylamino-6- Chlorofluorane, 3-dimethylamino-5,7-dimethylfluorane, 3-diethylamino-7-chlorofluorane, 3-dimethylamino-7-methylfluorane, 3-diethylamino-7,8-benzfluorane, 3-diethylamino-6-methyl-7-chlorofluorane, 3- (Np-tolyl-N-ethyl) Ruamino) -6-methyl-7-anilinofluorane, 3-pyrrolidino-6-methyl-7-anilinofluorane, 2- [N- (3′-trifluoromethylphenyl) amino] -6-diethylaminofluor Oran, 2- [3,6-bis (diethylamine) -9- (o-chloroanilino) xanthylbenzoate lactam], 3-diethylamino-6-methyl-7- (m-trichloromethylanilino) fluorane, 3-diethylamino -7- (o-chloroanilino) fluorane, 3-di-n-butylamino-7- (o-chloroanilino) fluorane, 3-N-methyl-Nn-amylamino-6-methyl-7-anilinofluorane 3-N-methyl-N-cyclohexylamino-6-methyl-7-anilinofluorane, 3-diethylamino-6-methyl 7-anilinofluorane, 3- (N, N-diethylamino) -5-methyl-7- (N, N-dibenzylamino) fluorane, benzoylleucomethylene blue, 6'-chloro-8'-methoxy-benzoindoli No-spiropyran, 6'-bromo-3'-methoxy-benzoindolino-spiropyran, 3- (2'-hydroxy-4'-dimethylaminophenyl) -3- (2'-methoxy-5'-chlorophenyl) Phthalide, 3- (2′-hydroxy-4′-dimethylaminophenyl) -3- (2′methoxy-5′-nitrophenyl) phthalide, 3- (2′-methoxy-4′-dimethylaminophenyl) -3 -(2'-Hydroxy-4'-chloro-5'-methylphenyl) phthalide, 3- (N-ethyl-N-tetrahydrofurfuryl) amino-6 -Methyl-7-anilinofluorane, 3-N-ethyl-N- (2-ethoxypropyl) amino-6-methyl-7-anilinofluorane, 3-N-methyl-N-isobutyl-6-methyl -7-anilinofluorane, 3-morpholino-7- (N-propyl-trifluoromethylanilino) fluorane, 3-pyrrolidino-7-m-trifluoromethylanilinofluorane, 3-diethylamino-5-chloro -7- (N-benzyl-trifluoromethylanilino) fluorane, 3-pyrrolidino-7- (di-p-chlorophenyl) methylaminofluorane, 3-diethylamino-5-chloro-7- (α-phenylethyl) Amino) fluorane, 3- (N-ethyl-p-toluidino) -7- (α-phenylethylamino) fluorane, 3-diethylamino-7 -(O-methoxycarbonylphenylamino) fluorane, 3-diethylamino-5-methyl-7- (α-phenylethylamino) fluorane, 3-diethylamino-7-piperidinofluorane, 2-chloro-3- (N -Methyl toluidino) -7- (pn-butylanilino) fluorane, 3- (N-methyl-N-isopropylamino) -6-methyl-7-anilinofluorane, 3-di-n-butylamino-6- Methyl-7-anilinofluorane, 3,6-bis (dimethylamino) fluorane spiro (9,3 ')-6'-dimethylaminophthalide, 3- (N-benzyl-N-cyclohexylamino) -5 , 6-Benzo-7-α-naphthylamino-4′-bromofluorane, 3-diethylamino-6-chloro-7-anilinofluorane, 3-die Tylamino-6-methyl-7-mesitidino-4 ′, 5′-benzofluorane, 3-N-methyl-N-isopropyl-6-methyl-7-anilinofluorane, 3-N-ethyl-N-isoamyl Examples include -6-methyl-7-anilinofluorane, 3-diethylamino-6-methyl-7- (2 ', 4'-dimethylanilino) fluorane.

  In the present invention, as the developer used in the heat-sensitive recording layer, various electron-accepting compounds that cause the coloration by contacting the leuco dye under heat, a solvent, or the like, or an oxidizing agent is applied. Such a thing is conventionally well-known and the following are mentioned as the specific example, However It is not limited only to this.

  4,4′-isopropylidenediphenol, 4,4′-isopropylidenebis (o-methylphenol), 4,4′-secondary butylidenebisphenol 4,4′-isopropylidenebis (2-tertiary-butylphenol), zinc p-nitrobenzoate, 1,3,5-tris (4-tertiarybutyl-3-hydroxy-2,6-dimethylbenzyl) isocyanuric acid, 2,2- (3,4'-dihydroxydiphenyl) propane, Bis (4-hydroxy-3-methylphenyl) sulfide, 4- [β- (p-methoxyphenoxy) ethoxy] salicylic acid, 1,7-bis (4-hydroxyphenylthio) -3,5-dioxaheptane, 1 , 5-bis (4-hydroxyphenylthio) -5-oxapentane, phthalic acid monobenzyl ester Calcium acid, 4,4′-cyclohexylidenediphenol, 4,4′-isopropylidenebis (2, -chlorophenol), 2,2′-methylenebis (4-methyl-6-tertiarybutylphenol), 4,4 '-Butylidenebis (6-tertiarybutyl-2-methyl) phenol, 1,1,3-tris (2-methyl-4-hydroxy-5-tertiarybutylphenyl) butane, 1,1,3-tris (2 -Methyl-4-hydroxy-5-cyclohexylphenyl) butane, 4,4'-thiobis (6-tertiarybutyl-2-methyl) phenol, 4,4'-diphenolsulfone, 4-isopropoxy-4'-hydroxy Diphenylsulfone, 4-benzyloxy-4'-hydroxydiphenylsulfone, 4,4'-diphenolsulfur Foxide, isopropyl p-hydroxybenzoate, benzyl p-hydroxybenzoate, benzyl protocatechuate, stearyl gallate, lauryl gallate, octyl gallate, 1,3-bis (4-hydroxyphenylthio) -propane, N, N '-Diphenylthiourea, N, N'-di (m-chlorophenyl) thiourea, salicylanilide, methyl bis- (4-hydroxyphenyl) acetate, benzyl bis- (4-hydroxyphenyl) acetate, 1,3-bis (4-hydroxyphenyl) benzyl acetate, 1,3-bis (4-hydroxycumyl) benzene, 1,4-bis (4-hydroxycumyl) benzene, 2,4′-diphenolsulfone, 2,2 ′ -Diallyl-4,4'-diphenolsulfone, 3,4-dihydroxyphenyl-4'-methyl Phenylsulfone, zinc 1-acetyloxy-2-naphthoate, zinc 2-acetyloxy-1-naphthoate, zinc 2-acetyloxy-3-naphthoate, α, α-bis (4-hydroxyphenyl) -α- Examples include methyltoluene, an antipyrine complex of zinc thiocyanate, tetrabromobisphenol A, tetrabromobisphenol S, 4,4′-thiobis (2-methylphenol), 4,4′-thiobis (2-chlorophenol), and the like.

  In the present invention, the developer used in the heat-sensitive recording layer is preferably 1 to 20 parts by weight, more preferably 2 to 10 parts by weight with respect to 1 part by weight of the color former. These color formers and color developers can be used alone or in admixture of two or more.

  A preferred binder resin for use in the thermosensitive recording layer is a resin having a hydroxyl group or a carboxyl group in the molecule. Examples of such resins include polyvinyl acetals such as polyvinyl butyral and polyvinyl acetoacetal, cellulose derivatives such as ethyl cellulose, cellulose acetate, cellulose acetate propionate, and cellulose acetate butyrate, and epoxy resins. It is not limited. Moreover, these binder resins are applied individually or in mixture of 2 or more types.

  In the heat-sensitive recording layer of the present invention, a heat-fusible substance can be used alone or in combination of two or more as an auxiliary additive component if necessary. Examples of heat-fusible substances include higher fatty acids or their esters, amides or metal salts, various waxes, condensation products of aromatic carboxylic acids and amines, benzoic acid phenyl esters, higher linear glycols, 3, 4 Examples include, but are not limited to, those having a melting point of about 50 to 200 ° C., such as epoxy-hexahydrophthalate dialkyl, higher ketones, and other heat-fusible organic compounds.

  In the case of obtaining the heat-sensitive recording layer in the present invention, an additive component commonly used for this type of heat-sensitive recording medium, if necessary, together with a leuco dye, a developer, a binder resin, for example, a filler, a surfactant, a lubricant, a pressure An anti-coloring agent or the like can be used in combination as long as the transparency of the heat-sensitive recording layer is not impaired.

  In this case, as a filler, for example, calcium carbonate, silica, zinc oxide, titanium oxide, aluminum hydroxide, zinc hydroxide, barium sulfate, clay, kaolin, talc, surface-treated inorganic fine powder such as calcium and silica, Examples thereof include organic fine powders such as urea-formalin resin, styrene / methacrylic acid copolymer, polystyrene resin, and vinylidene chloride resin. Examples of the lubricant include higher fatty acids and metal salts thereof, higher fatty acid amides, higher fatty acid esters, various animal, vegetable, mineral, and petroleum waxes.

  The heat-sensitive recording layer is prepared by uniformly dispersing or dissolving the color former, developer, and binder resin in a solvent, and coating and drying this on a support made of fine paper or film. Is not particularly limited. The dispersed particle size of the thermal recording layer coating solution is preferably 10 μm or less, more preferably 5 μm or less, and even more preferably 1 μm or less. The film thickness of the heat-sensitive recording layer is about 1 to 50 μm, preferably about 3 to 20 μm, although it depends on the composition of the heat-sensitive recording layer and the application of the thermoadhesive label.

  The recording method of the heat-sensitive recording layer of the present invention is not particularly limited depending on the purpose of use, such as a thermal pen, a thermal head, or laser heating.

  The support used in the present invention is not particularly limited. For example, in addition to paper, cloth, and film, transparent materials include polyester films such as polyethylene terephthalate and polybutylene terephthalate, cellulose derivative films such as cellulose triacetate, and polypropylene. In general, a polyolefin film such as polyethylene, a polystyrene film, or a transparent film obtained by bonding them together is used.

  In the present invention, a protective layer can be provided on the thermosensitive recording layer. The protective layer used in the present invention improves the so-called head matching properties such as transparency, chemical resistance, water resistance, friction resistance, light resistance and thermal head durability, corrosion resistance, and lubricity of the thermal recording layer. Therefore, it is important as a component of the present invention. The protective layer includes a film formed mainly with a water-soluble resin or a hydrophobic resin, a film formed mainly with an ultraviolet curable resin or an electron beam curable resin, and the like. Examples of such resins include water-soluble resins, aqueous emulsions, hydrophobic resins and ultraviolet curable resins, and electron beam curable resins.

  Specific examples of the water-soluble resin include, for example, polyvinyl alcohol, modified polyvinyl alcohol, cellulose derivatives (methylcellulose, methoxycellulose, hydroxycellulose, etc.), casein, gelatin, polyvinylpyrrolidone, styrene-maleic anhydride copolymer, diisobutylene- Maleic anhydride copolymer, polyacrylamide, modified polyacrylamide, methyl vinyl ether-maleic anhydride copolymer, carboxy-modified polyethylene, polyvinyl alcohol / acrylamide block copolymer, melamine-formaldehyde resin, urea-formaldehyde resin, etc. .

  Examples of the resin or hydrophobic resin for aqueous emulsion include polyvinyl acetate, polyurethane, styrene / butadiene copolymer, styrene / butadiene / acrylic copolymer, polyacrylic acid, polyacrylic ester, vinyl chloride / acetic acid. Examples thereof include vinyl copolymers, polybutyl methacrylate, polyvinyl butyral, polyvinyl acetal, methyl cellulose, ethyl cellulose, and ethylene / vinyl acetate copolymers.

  Further, copolymers of these resins and silicon segments are also preferably used. These may be used alone or in combination, and if necessary, a curing agent may be added to cure the resin.

  The type of the ultraviolet curable resin is not particularly limited as long as it is a monomer, oligomer or prepolymer that undergoes a polymerization reaction upon irradiation with ultraviolet rays and is cured to become a resin, and various known ones can be used.

  The type of the electron beam curable resin is not particularly limited, but particularly preferable electron beam curable resins include an electron beam curable resin having a branched molecular structure of five or more functional groups having a polyester skeleton and a silicon-modified electron beam curable resin. The main component.

  In order to improve head matching, inorganic and / or organic fillers and lubricants can be added to the protective layer as long as the surface smoothness is not deteriorated. The particle size of the filler is preferably 0.3 μm or less. In this case, the filler is preferably selected so that the amount of oil supply is 30 ml / 100 or more, more preferably 80 ml / 100 g or more.

  As these inorganic and / or organic fillers, one or two or more of pigments commonly used in this type of thermal recording medium can be selected. Specific examples thereof include calcium carbonate, silica, zinc oxide, titanium oxide, aluminum hydroxide, zinc hydroxide, barium sulfate, clay, talc, surface-treated inorganic pigments such as calcium and silica, urea-formalin resin, Examples thereof include organic pigments such as styrene / methacrylic acid copolymers and polystyrene resins. As the lubricant, those mentioned in the description of the heat-sensitive recording layer can be used.

  There is no restriction | limiting in particular in the coating system of a protective layer, It can apply by a conventionally well-known method. A preferable thickness of the protective layer is 0.1 to 20 μm, more preferably 0.5 to 10 μm. If the thickness of the protective layer is too thin, the function as a protective layer such as storage stability and head matching of the thermoadhesive label is insufficient, and if it is too thick, the thermal sensitivity of the thermosensitive recording layer is lowered, resulting in cost reduction. Is also disadvantageous.

  In the present invention, a heat insulating layer (under layer) is provided between the support and the pressure-sensitive adhesive layer and / or between the support and the heat-sensitive recording layer as necessary. By providing this heat insulating layer, the thermal energy efficiency of the thermal head can be improved and the thermal activation temperature can be lowered. Furthermore, when a pressure sensitive adhesive layer is thermally activated, if a heat sensitive recording layer is provided on the opposite surface, the color development of the heat sensitive recording layer can be blocked. The heat insulating layer may be used in combination with fine hollow particles and a binder, if necessary, a pigment, and auxiliary additive components commonly used in this type of heat-sensitive recording material, for example, a heat-fusible substance, a filler, and a surfactant. it can. In this case, as a specific example of the heat-fusible substance, the same material as the heat-fusible substance described in the description of the heat-sensitive recording layer is used.

  Examples of the resin used in the heat insulating layer containing fine hollow particles in the present invention include the following compounds, but are not necessarily limited thereto. Latex such as SBR, MBR, NBR and polyvinyl alcohol, cellulose derivatives, starch and derivatives thereof, carboxyl group-modified polyvinyl alcohol, polyacrylic acid and derivatives thereof, styrene / acrylic acid copolymers and derivatives thereof, poly (meth) acrylamide and Examples thereof include water-soluble polymer resins such as derivatives thereof, styrene / acrylic acid / acrylamide copolymers, amino group-modified polyvinyl alcohol, epoxy-modified polyvinyl alcohol, polyethyleneimine, isobutylene / maleic anhydride copolymer and derivatives thereof. .

  In addition, as the filler, for example, calcium carbonate, silica, zinc oxide, titanium oxide, aluminum hydroxide, zinc hydroxide, barium sulfate, clay, talc, surface-treated inorganic fine powder such as calcium and silica, Examples thereof include organic fine powders such as urea-formalin resin, styrene / methacrylic acid copolymer, and polystyrene resin.

  Examples of the heat insulating layer in the present invention include a non-foaming heat insulating layer using micro hollow particles having a hollowness of 30% or more or a porous pigment having a thermoplastic resin as a shell, and a foaming heat insulating layer using a foaming filler. Preferably, it is a non-foaming heat insulating layer.

  The fine hollow particles having a hollowness of 30% or more having a thermoplastic resin as a shell used in the heat insulating layer in the present invention are fine hollow particles that contain air or other gas inside and are already in a foamed state. The number average particles are preferably 2.0 to 20 μm, more preferably 3 to 10 μm. When the number average particle diameter (particle outer diameter) is smaller than 2.0 μm, there are problems in production such as difficulty in making an arbitrary hollowness, and there is a problem in terms of cost. Larger ones reduce the smoothness of the surface after coating and drying, thereby lowering the adhesion with the thermal head, resulting in poor dot reproducibility and a reduction in sensitivity. Accordingly, it is desirable that such particle distribution has a uniform particle distribution spectrum with a small variation in particle diameter.

  Furthermore, the plastic spherical hollow particles used in the present invention may preferably have a hollowness of 30% or more, but more preferably 50% or more. When the hollowness is less than 30%, the heat insulating property is insufficient. Therefore, the thermal energy from the thermal head is released to the outside of the heat-adhesive label through the support, and the color development sensitivity is not improved. There is little heat insulation effect of the heat energy of heat conversion, the effect of activation of a pressure sensitive adhesive is inferior, and the expression of adhesiveness is weakened.

  In addition, the hollowness here is a ratio of the outer diameter and the inner diameter of the hollow particles, and is represented by the following formula.

  As described above, the fine hollow particles used in the present invention have a thermoplastic resin as a shell, and as the thermoplastic resin, a copolymer resin mainly composed of vinylidene chloride and acrylonitrile is preferable. Other porous pigments used in the heat insulating layer of the present invention include organic pigments such as urea formaldehyde resin and inorganic pigments such as shirasu earth, but are not necessarily limited thereto.

In order to provide a non-foaming heat insulating layer between the support and the heat-sensitive recording layer and / or between the support and the pressure-sensitive adhesive layer, the above-mentioned fine hollow particles are replaced with a known water-soluble polymer or aqueous polymer. It is obtained by dispersing with water together with a binder such as an emulsion, applying this to the surface of the support and drying. In this case, the coating amount of the fine hollow particles is at least 1 g per 1 m ² of the support, preferably about ^{2 to} 15 g, and the coating amount of the binder resin is such that the non-foaming heat insulating layer is strongly bonded to the support. The amount may be sufficient, and is usually 2 to 50% by weight based on the total amount of the fine hollow particles and the binder resin.

  In the present invention, the binder used when forming the non-foamable heat insulating layer is appropriately selected from conventionally known water-soluble polymers and / or aqueous polymer emulsions.

  Specific examples include water-soluble polymers such as polyvinyl alcohol, starch and derivatives thereof, cellulose derivatives such as methoxycellulose, hydroxyethylcellulose, carboxymethylcellulose, methylcellulose, and ethylcellulose, sodium polyacrylate, polyvinylpyrrolidone, acrylamide / acrylic. Acid ester copolymer, acrylamide / acrylic acid ester / methacrylic acid terpolymer, styrene / maleic anhydride copolymer alkali salt, isobutylene / maleic anhydride copolymer alkali salt, polyacrylamide, sodium aluminate, gelatin , Casein and the like.

  Examples of the aqueous polymer emulsion include latex such as styrene / butadiene copolymer, styrene / butadiene / acrylic copolymer, vinyl acetate resin, vinyl acetate / acrylic acid copolymer, and styrene / acrylic acid ester copolymer. And emulsions such as acrylic ester resins and polyurethane resins.

  Next, the present invention will be described in more detail with reference to examples. In addition, all the parts and% shown below are based on weight.

[Example 1]
(Liquid A) Dye dispersion 3-dibenzylamino-6-methyl-7-
Anilinofluorane 20 parts Polyvinyl alcohol 10% aqueous solution 20 parts Water 60 parts (Liquid B) Developer dispersion 4,4'-dihydroxybenzophenone 10 parts Polyvinyl alcohol 10% aqueous solution 25 parts Calcium carbonate 15 parts Water 50 parts Above composition (A liquid) and (B liquid) were prepared by dispersing the mixture consisting of using a sand mill so that the average particle diameter was 2.0 μm or less. Next, the mixture was stirred so that the weight ratio of (A liquid) to (B liquid) was (A liquid) :( B liquid) = 1: 8 to obtain a thermosensitive recording layer forming liquid (C liquid). This thermal recording layer forming liquid (C solution) was applied and dried on the surface of high-quality paper having a basis weight of 80 g / m ² so that the dry adhesion amount was 5 g / m ^2, and a thermal recording layer was provided. Further, the paper was formed with a heat-sensitive recording layer by supercalendering so that the Peck smoothness was 600 to 700 seconds.

Next, a polyvinyl acetate emulsion as a pressure-sensitive adhesive is applied and dried on the back surface of the heat-sensitive recording layer-formed paper so as to have a dry adhesion amount of 18 g / m ² , and a pressure-sensitive adhesive layer is provided to provide a pressure-sensitive adhesive sheet. Got.
An olefin / acrylic copolymer emulsion (manufactured by Chuo Rika Kogyo Co., Ltd .: trade name Rikabond ET-1000) was applied on the pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet with a dry adhesion amount of 3.2 g / m ² . The coating layer was dried to provide a seal layer, and a linerless thermal adhesive label was obtained.

[Example 2]
Linerless in the same manner as in Example 1 except that the olefin / acrylic copolymer of Example 1 was replaced with an ethylene / vinyl acetate copolymer (manufactured by Chuo Rika Kogyo Co., Ltd .: trade name Aquatex EC-1200). A heat-adhesive label was obtained.

Example 3
Linerless thermal adhesion in the same manner as in Example 1 except that the olefin / acrylic copolymer of Example 1 was replaced with an olefin copolymer (manufactured by Chuo Rika Kogyo Co., Ltd .: trade name Aquatex EC-3500). A sex label was obtained.

Example 4
A linerless thermal adhesive label was obtained in the same manner as in Example 1 except that the dry adhesion amount of the seal layer of Example 1 was changed to 2 g / m ² .

Example 5
A linerless thermoadhesive label was obtained in the same manner as in Example 1 except that the dry adhesion amount of the seal layer in Example 1 was changed to 4 g / m ² .

Example 6
A linerless thermal adhesive label was obtained in the same manner as in Example 1 except that the dry adhesion amount of the seal layer in Example 1 was changed to 1.8 g / m ² .

Example 7
A linerless thermal adhesive label was obtained in the same manner as in Example 1 except that the dry adhesion amount of the seal layer in Example 1 was changed to 4.3 g / m ² .

[Comparative Example 1]
An olefin / acrylic copolymer emulsion (manufactured by Chuo Rika Kogyo Co., Ltd .: trade name Rikabond ET-1000) is dried on the back surface of the heat-sensitive recording layer-formed paper of Example 1 so that the dry adhesion amount is 14 g / m ^2. It was coated and dried to obtain a linerless thermal adhesive label.

[Comparative Example 2]
A linerless heat-adhesive label was prepared in the same manner as in Example 1 except that the olefin / acrylic copolymer of Example 1 was replaced with a delayed tack paste (Regex Corp .: DT-200) using a solid plasticizer. Obtained.

[Comparative Example 3]
(Liquid D) Preparation of solid plasticizer dispersion 100 parts of dicyclohexyl phthalate (melting point 64 ° C.) as a solid plasticizer and nonionic surfactant (trade name: Neugen EA-120, Daiichi Kogyo Seiyaku) as a dispersant 2.4 parts) and water were uniformly mixed to a concentration of 56%, and pulverized using a ball mill to an average particle size of 2.0 μm to prepare a solid plasticizer dispersion.
(E liquid) Preparation of heat-sensitive adhesive layer coating liquid 200 parts of solid plasticizer dispersion liquid (D liquid), vinyl acetate / ethylene copolymer emulsion (Sumitomo Chemical Co., Ltd., Sumikaflex 910) as a thermoplastic resin A glass transition temperature of −20 ° C.) and 100 parts of a rosin ester dispersion (Arakawa Chemical Industries, Ltd., Superester E-730) as a tackifier were mixed to produce a heat sensitive solid content of 50% by weight. An adhesive layer coating solution was prepared.
On the back side of the heat-sensitive recording layer-formed paper of Example 1, the heat-sensitive adhesive layer coating liquid (E liquid) prepared by the above method was applied and dried to 25 g / m ² to form a heat-sensitive adhesive layer. did.
Next, a thermoplastic resin coating solution (styrene / acrylic acid ester copolymer emulsion: manufactured by Nippon SC Co., Ltd., GD902; glass transition temperature 40 ° C.) is 2 g / m ² on the heat-sensitive adhesive layer. The thermoplastic resin layer was applied and dried to obtain a linerless thermoadhesive label.

[Comparative Example 4]
In Comparative Example 3, except that the olefin / acrylic copolymer emulsion used in Example 1 was used instead of the styrene / acrylic acid ester copolymer emulsion as the thermoplastic resin coating liquid on the heat-sensitive adhesive layer. In the same manner as in Comparative Example 3, a linerless thermal adhesive label was obtained.

  Then, evaluation (adhesiveness, blocking property) about the samples (thermal adhesive labels) obtained in Examples 1 to 7 and Comparative Examples 1 to 4 was performed. The results are shown in Table 1.

[Adhesiveness]:
The thermal power printing apparatus having the label samples prepared in Examples and Comparative Examples and the thin film head manufactured by Matsushita Electronic Parts Co., Ltd. was allowed to stand for 1 hour or more at room temperature (20 ° C., 60% RH), and then the head power The pressure sensitive adhesive layer was activated with a pulse width of 0.5 msec under the conditions of 0.60 W / dot, 1 line recording time 10 msec / 11 in, and scanning line density 8 × 7: 7 dots / mm. Immediately after being attached to an adherend (corrugated cardboard, PE wrap) and after 1 week, the adhesive strength was evaluated in the following rank.
◎: Adhering strongly ○: Adhering △: Adhering slightly ×: Not adhering (peeling)

[Blocking property]:
The front and back surfaces of the same label sample are brought into contact with each other, tested at 40 ° C. for 24 hours under a pressure of ² kg / cm ² , then left at room temperature, and then the sample is peeled off. It was evaluated in such a rank.
◎: No blocking (no crackling sound)
○: No blocking occurred (there is a crackling sound)
Δ: Slight blocking

Claims (5)

A heat-adhesive label in which a pressure-sensitive adhesive layer is provided on a support, and a seal layer is further provided on the pressure-sensitive adhesive layer, the seal layer comprising only a hot melt resin, The hot melt resin is at least one selected from an olefin / acrylic copolymer, an ethylene / vinyl acetate copolymer, and an olefin copolymer, and has a dry adhesion amount of 1.8 to 4.3 g / m ² . thermal adhesive labels, characterized in that. The heat-adhesive label according to claim 1, wherein the adhesion amount of the seal layer is ² to 4 g / m ² . The heat-adhesive label according to claim 1 or 2 , wherein a heat-sensitive recording layer is provided on a surface of the support opposite to the pressure-sensitive adhesive layer. The thermal activation method for a thermoadhesive label according to any one of claims 1 to 3 , wherein heating is performed with a thermal head. A method for producing a thermoadhesive label according to any one of claims 1 to 3 , wherein a seal layer is provided on the pressure-sensitive adhesive layer of a pressure-sensitive adhesive sheet provided with a pressure-sensitive adhesive layer on a support. A method for producing a heat-adhesive label, comprising: forming a sealing layer composed only of the hot-melt resin by applying and drying an emulsion liquid of the hot-melt resin.