JP2017177346A - Thermosensitive recording linerless label and method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermosensitive recording linerless label that does not cause deterioration in color developing ability after long-term storage, particularly even though it is stored for a long period of time under a high temperature and high humidity environment, i.e., free from desensitization due to starch and is excellent in heat resistance of a white paper part.SOLUTION: A thermosensitive recording linerless label has a support, a thermosensitive recording layer containing a dye precursor, a developer and a sensitizer, a protective layer containing an adhesive, and a release layer in this order from the side close to the support on one surface of the support, and has a pressure-sensitive adhesive layer on the other surface of the support. The thermosensitive recording linerless label contains as the developer at least one kind selected from the group consisting of N-[2-(3-phenylureido)phenyl]benzenesulfonamide, 4-hydroxy-4'-n-propoxydiphenylsulfone, and 4-hydroxy-4'-allyloxydiphenylsulfone, and contains as the sensitizer N-substituted fatty acid amide.SELECTED DRAWING: None

Description

  The present invention relates to a heat-sensitive recording material that utilizes a color-forming reaction between an electron-donating compound and an electron-accepting compound and that can obtain a recorded image by a color-forming reaction by thermal energy.

  A heat-sensitive recording material in which a recorded image is obtained by bringing an electron-donating compound and an electron-accepting compound into contact with each other by thermal energy is well known. Such a heat-sensitive recording material is relatively inexpensive, has a compact recording device, and is easy to maintain. Therefore, it is used for recording media such as facsimiles and various computers.

  In recent years, in particular, receipts for gas, water, electricity bills, ATM usage statements for financial institutions, various receipts, etc., financial record sheets (for so-called handy terminals), thermal recording labels for POS systems, and thermal recording labels. Opportunities to use various bar codes by thermal recording and printing on recording tags and the like are increasing, and there is a need for a thermal recording body having barcode printing suitability.

  In such a heat-sensitive recording material, a pressure-sensitive adhesive layer is provided on the back surface of the heat-sensitive recording layer, and a release paper is bonded to the recording device in a wound state. Since the thickness of such a heat-sensitive recording adhesive sheet is increased by the preparation of the adhesive layer and release paper, the length of the heat-sensitive recording adhesive sheet that can be loaded into the recording device is also limited, and the release paper that is generated during pasting after recording This processing is also a problem from the viewpoint of resource saving.

  Various pressure-sensitive adhesive sheets for thermal recording that do not use release paper have been proposed, and are used in a wound state in which a release layer containing a silicone resin or the like is provided on a thermal recording material and an adhesive layer is provided on the back surface (patent) References 1-4). However, various problems occur when the release layer and the pressure-sensitive adhesive layer are overlapped with the heat-sensitive recording layer.

  In general, the adhesive includes a solvent system, an emulsion system, a hot melt system, and the like, but an emulsion system is often used from the viewpoint of environment and manufacturing equipment. The emulsion-based pressure-sensitive adhesive is mainly obtained by emulsion polymerization of an acrylate monomer, but requires additives such as an emulsifier, a stabilizer, a dispersant, and the pressure-sensitive adhesive layer contains these additives. These additives may adversely affect the coloring components of the heat-sensitive recording layer, and when stored for a long time, especially in a high-temperature and high-humidity environment, the developer and sensitizer of the heat-sensitive recording layer are added to the pressure-sensitive adhesive layer. There is a defect that the color development ability is remarkably deteriorated, that is, the so-called glue desensitization.

  In other words, thermal recording linerless labels that do not use release paper have not fully solved the printing obstacles caused by adhesives and release agents, and require far stricter quality than conventional labels that use release paper. Has been. Thermal recording that does not cause problems even when used under severe conditions such as distribution management applications, is compatible with high-speed issuance, has excellent recording suitability, and does not cause printing problems even if recorded for a long time. There is a strong demand for linerless labels.

JP 60-54842 A Japanese Patent Laid-Open No. 2-165898 Japanese Patent Laid-Open No. 5-8541 JP-A-6-222717 JP 2013-195889 A

  An object of the present invention is to provide a thermal recording liner that does not deteriorate in color development ability even after being stored for a long time in a high-temperature and high-humidity environment after long-term storage. The main purpose is to provide a less label.

  As a result of intensive studies, the present inventors have solved the above-mentioned problems by incorporating a specific developer and a sensitizer into the heat-sensitive recording layer. That is, the present invention relates to the following thermal recording linerless label.

  Item 1: A support, a heat-sensitive recording layer containing a dye precursor, a developer, and a sensitizer on one side of the support from the side close to the support, a protective layer containing an adhesive, and A thermal recording linerless label having a release layer and having an adhesive layer on the other surface of the support, wherein the developer is N- [2- (3-phenylureido) phenyl] benzenesulfonamide, Contains at least one selected from the group consisting of 4-hydroxy-4′-n-propoxydiphenylsulfone and 4-hydroxy-4′-allyloxydiphenylsulfone, and contains an N-substituted fatty acid amide as the sensitizer. A thermal recording linerless label.

  Item 2: The thermal recording linerless label according to Item 1, wherein the N-substituted fatty acid amide has a melting point in the range of 110 to 160 ° C.

  Item 3: The adhesive contained in the protective layer is at least one selected from the group consisting of acetoacetyl-modified polyvinyl alcohol, diacetone-modified polyvinyl alcohol, carboxy-modified polyvinyl alcohol, and silicon-modified polyvinyl alcohol, 2. The thermal recording linerless label according to 2.

  Item 4: The heat-sensitive recording linerless label according to any one of Items 1 to 3, wherein the pressure-sensitive adhesive layer comprises a water-based pressure-sensitive adhesive.

  Item 5: A support, a heat-sensitive recording layer containing a dye precursor, a developer, and a sensitizer from the side close to the support on one side of the support, a protective layer containing an adhesive, and A method for producing a thermal recording linerless label having a release layer and having an adhesive layer on the other side of the support, wherein N- [2- (3-phenylureido) phenyl] benzenesulfone is used as the developer. N-substituted fatty acid amide containing at least one selected from the group consisting of amide, 4-hydroxy-4′-n-propoxydiphenyl sulfone, and 4-hydroxy-4′-allyloxydiphenyl sulfone A step of forming a heat-sensitive recording layer on one side of the support using a heat-sensitive recording layer-containing coating liquid, and a pressure-sensitive adhesive on the other side of the support using a pressure-sensitive adhesive layer-containing coating liquid containing an adhesive Step of forming a layer Method for producing a thermosensitive recording linerless label comprising.

  The thermal recording linerless label of the present invention is not deteriorated in coloring ability even when stored for a long period of time in a high temperature and high humidity environment after long-term storage, that is, there is no desensitization and the heat resistance of the white paper portion is excellent. . It is also resistant to chemicals.

  The heat-sensitive recording linerless label in the present invention contains a support, a heat-sensitive recording layer containing a dye precursor, a developer and a sensitizer from one side of the support close to the support, and an adhesive. A protective layer and a release layer, and an adhesive layer on the other surface.

  In the thermal recording linerless label, by using an acrylic emulsion as an adhesive, the developer and sensitizer contained in the thermal recording layer move over time to the adhesive layer through the protective layer and the release layer. Tend. This tendency is strong with developers and sensitizers that are easily soluble in water, especially when moving at high temperatures and high humidity, and the content of developers and sensitizers in the heat-sensitive recording layer is reduced, resulting in significantly improved thermal coloring performance. It may be damaged. As the developer used for the heat-sensitive recording layer, a phenolic compound is mainly used, and it is considered that the developer easily moves from the heat-sensitive recording layer to the pressure-sensitive adhesive layer due to compatibility with water due to hydroxyl groups. Many of the compounds used as sensitizers have a low molecular weight, so the effect of water solubility is considered.

  The pressure-sensitive adhesive used for a label using a paper substrate as a support is a water-based pressure-sensitive adhesive obtained by emulsion polymerization or a hot-melt type that hardly contains an emulsifier. The hot melt type is a method in which the base polymer is heated and melted and applied to the base material. A drying process is not required and the space for accommodating equipment can be reduced. However, since the raw material is a special polymer, There are problems such as high price, melting, introduction of nitrogen gas into the coating process, and difficulty in modification by crosslinking. The water-based pressure-sensitive adhesive obtained by emulsion polymerization requires a drying process, but if it is a facility designed exclusively for water-based from the beginning, there is an economic advantage and its use in Japan is increasing. However, since an adhesive is essentially produced by emulsion polymerization, it contains a surfactant. For example, when it comes into contact with a film such as soft polyvinyl chloride, there is a problem that the plasticizer contained in the film shifts to the adhesive. Yes, it may affect the adhesive performance. In the case of a thermal recording linerless label, when a general developer, a sensitizer, etc. contained in the thermal recording layer come into contact with a plasticizer of a film such as soft polyvinyl chloride, there is a problem of shifting to an adhesive layer. In particular, the tendency to shift becomes strong in a high temperature and high humidity environment.

  As a specific example of the water-based pressure-sensitive adhesive obtained by emulsion polymerization, an acrylic pressure-sensitive adhesive is mainly used, and other vinyl polymers and functional group monomers are mainly composed of butyl acrylate and 2-ethylene hexyl acrylic monomers. In general, the glass transition point is designed to be −30 ° C. or lower and copolymerized. In general, an alkylphenol type nonion is mainly used as a surfactant, and an anionic type is often used in a small amount. As the polymerization initiator, a water-soluble peroxide catalyst such as ammonium persulfate is used. However, in order to improve the emulsion stability during the polymerization, the polymerization is preferably carried out at a relatively low temperature, and a reduction such as acidic sodium sulfite. A redox polymerization method using an agent in combination is often used. These are used in the form of an emulsion. In the present invention, when a paper support that normally retains moisture is used as the support and a water-based adhesive is used as the adhesive, the effect on water solubility can be remarkably exhibited.

  The protective layer in the present invention contains an adhesive. Although it does not specifically limit as an adhesive agent, From a viewpoint of improving barrier property, a water-soluble or water-dispersible water-based adhesive agent is preferable. In particular, at least one water-soluble adhesive selected from acetoacetyl-modified polyvinyl alcohol, diacetone-modified polyvinyl alcohol, carboxy-modified polyvinyl alcohol, and silicon-modified polyvinyl alcohol is preferably used.

  Acetoacetyl-modified polyvinyl alcohol, diacetone-modified polyvinyl alcohol, carboxy-modified polyvinyl alcohol, and silicon-modified polyvinyl alcohol are obtained by copolymerizing a monomer having an acetoacetyl group, a diacetone group, a carboxyl group, and a silyl group with a vinyl ester, respectively. It is produced by saponifying the resin obtained.

  The degree of saponification is preferably about 85 mol% to 100 mol% of complete saponification, more preferably about 90 to 100 mol%. About average polymerization degree, about 300-3000 are preferable and about 400-2000 are more preferable. The degree of modification is preferably about 0.5 to 10 mol%, more preferably about 1 to 9 mol% from the viewpoint of improving water resistance. The higher the degree of polymerization and the degree of saponification, the better the water resistance, but it is necessary to select from the paint concentration, viscosity, coating property or drying property according to the situation.

  At least one amount selected from the group consisting of acetoacetyl-modified polyvinyl alcohol, diacetone-modified polyvinyl alcohol, carboxy-modified polyvinyl alcohol, and silicon-modified polyvinyl alcohol used in the protective layer is the total solid amount of the protective layer. , Preferably it is 10-90 mass%, More preferably, it is about 15-50 mass%.

  Other adhesives can be used in combination as long as the effects of the present invention are not impaired. Examples of the adhesive include fully saponified polyvinyl alcohol, partially saponified polyvinyl alcohol, starch, oxidized starch, hydroxyethyl cellulose, methyl cellulose, carboxymethyl cellulose, gelatin, casein, gum arabic, diisobutylene / maleic anhydride copolymer salt, styrene Maleic anhydride copolymer salt, ethylene / acrylic acid copolymer salt, styrene / acrylic acid copolymer salt, urea resin, melamine resin, amide resin, acrylic resin latex, urethane resin latex and the like.

  The protective layer in the present invention may contain a pigment. Examples of the pigment include inorganic pigments such as calcium carbonate, zinc oxide, aluminum oxide, titanium dioxide, amorphous silica, aluminum hydroxide, barium sulfate, talc, kaolin, and calcined kaolin. Of these, kaolin and aluminum hydroxide are particularly preferably used since they have a small decrease in barrier properties against chemicals such as plasticizers and oils and a small decrease in recording density.

  Examples of auxiliary agents that can be contained in the protective layer include lubricants such as zinc stearate, calcium stearate, carnauba wax, paraffin wax, and ester wax, sodium alkylbenzene sulfonate, sodium dioctyl sulfosuccinate, sulfone-modified polyvinyl alcohol, and polyacrylic acid. Surfactants such as sodium, water resistant agents such as dialdehyde starch, methylol urea, glyoxylate, epoxy compounds, hydrazine compounds, and UV absorbers, fluorescent dyes, coloring dyes, mold release agents, antioxidants, etc. Is mentioned.

The protective layer is, for example, a coating solution for the protective layer prepared by mixing and stirring a specific adhesive, if necessary, a pigment, an auxiliary agent, etc., using water as a dispersion medium, and the coating amount is preferably 0 by dry weight. .1~8g / ^{m 2} approximately, is formed and more preferably 0.5 to 5 g / ^{m 2} approximately, more preferably such that 1 to 4 g / ^{m 2} approximately, by coating and drying the heat-sensitive recording layer .

  The thermal recording linerless label forms a release layer on the protective layer, but as the release silicone, solvent-based, solvent-free, emulsion-based depending on the form, and thermosetting type from the difference in curing mode, Broadly divided into ultraviolet and electron beam curable types. From the viewpoint of environmental problems and that the heat-sensitive recording layer is required not to develop color, it is preferable to use a coating solution for a release layer mainly composed of ultraviolet rays or an electron beam curable silicone compound. Specific examples of these silicone compounds include a mixture composition of a mercapto group-containing organosiloxane and a vinyl group-containing organopolysiloxane, an acrylic group, a methacryl group or a cinnamoyl group-containing organopolysiloxane composition, a maleimide group or a phenol maleimide group. Containing arganopolysiloxane composition, mixed composition of azido group-containing organopolysiloxane and vinyl group-containing organopolysiloxane, thioacryl group, thiomethacryl group or thiocinnamoyl group-containing organopolysiloxane composition, acrylamide group, methacrylamide group Or an organopolysiloxane composition containing a cinnamoylamide group, and an epoxy group-containing organopolysiloxane utilizing ultraviolet-initiated cationic polymerization and a photolytic initiator diazonium. Mixed composition of chair salts can also be utilized. In the case of UV curing, a photopolymerization initiator is required, and specific examples include benzoyl alkyl ether and derivatives thereof, acetophenone and derivatives thereof, thioxanthone and derivatives thereof, and boron-based cation derivatives.

  The heat-sensitive recording layer in the present invention contains a dye precursor, a developer, and a sensitizer. Since a combination of a leuco dye and a developer as a dye precursor is excellent in color density, it is preferably used.

  Specific examples of the leuco dye include 3,3-bis (p-dimethylaminophenyl) -6-dimethylaminophthalide and 3- (4-diethylamino-2-methylphenyl) -3- (4-dimethylaminophenyl). ) -6-dimethylaminophthalide, 3- (N-ethyl-Np-tolyl) amino-7-N-methylanilinofluorane, 3-cyclohexylamino-6-chlorofluorane, 3-diethylamino-6 -Methyl-7-chlorofluorane, 3-diethylamino-7-chlorofluorane, 3- (N-ethyl-N-isoamyl) amino-6-methyl-7-anilinofluorane, 3-di (n-butyl) ) Amino-6-methyl-7-anilinofluorane, 3-di (n-pentyl) amino-6-methyl-7-anilinofluorane, 3- (N-ethyl-p) Toluidino) -6-methyl-7-anilinofluorane, 3-di (n-butyl) amino-6-chloro-7-anilinofluorane, 3-pyrrolidino-6-methyl-7-anilinofluorane, 3-piperidino-6-methyl-7-anilinofluorane, 3,3-bis [1- (4-methoxyphenyl) -1- (4-dimethylaminophenyl) ethylene-2-yl] -4,5 6,7-tetrachlorophthalide, 3-p- (p-dimethylaminoanilino) anilino-6-methyl-7-chlorofluorane, 3-p- (p-chloroanilino) anilino-6-methyl-7- Examples include chlorofluorane, 3,6-bis (dimethylamino) fluorene-9-spiro-3 ′-(6′-dimethylamino) phthalide, and the like.

  Of course, it is not limited to these, Moreover, 2 or more types can also be used together. The content of the leuco dye is not limited because it varies depending on the developer used, but is preferably about 3 to 50% by mass and more preferably about 5 to 40% by mass in the total solid content of the heat-sensitive recording layer.

  In the present invention, N- [2- (3-phenylureido) phenyl] benzenesulfonamide, 4-hydroxy-4′-n-propoxydiphenylsulfone, and 4-hydroxy-4′-allyloxydiphenylsulfone are used as developers. And at least one selected from the group consisting of N-substituted fatty acid amides as sensitizers. By containing these color developers and sensitizers, it is possible to suppress glue desensitization without suppressing water solubility and without lowering the color development performance even during long-term storage in a high-temperature and high-humidity environment. In addition, the coloring sensitivity and heat resistance can be improved, and the resistance to chemicals can be improved.

  The content of the developer is not limited because it varies depending on the leuco dye used, but is preferably about 10 to 70% by mass and more preferably about 12 to 50% by mass in the total solid content of the heat-sensitive recording layer.

  Examples of other developers include 4,4′-isopropylidene diphenol, 4,4′-cyclohexylidene diphenol, 1,1-bis (4-hydroxyphenyl) ethane, 1,1-bis (4- Hydroxyphenyl) -1-phenylethane, 4,4′-dihydroxydiphenylsulfone, 2,4′-dihydroxydiphenylsulfone, 4-hydroxy-4′-isopropoxydiphenylsulfone, 3,3′-diallyl-4,4 ′ -Dihydroxydiphenylsulfone, 2,2'-bis [4- (4-hydroxyphenyl) phenoxy] diethyl ether, Np-toluenesulfonyl-N'-3- (p-toluenesulfonyloxy) phenylurea, 4,4 '-Bis [(4-methyl-3-phenoxycarbonylaminophenyl) ureido] dipheni Sulfone, 4-hydroxybenzoic acid benzyl ester, N, N'-di-m-chlorophenylthiourea, Np-tolylsulfonyl-N'-phenylurea, 4,4'-bis (p-tolylsulfonylaminocarbonylamino) ) Diphenylmethane, 4- [2- (p-methoxyphenoxy) ethyloxy] salicylic acid zinc, 4- {3- (p-tolylsulfonyl) propyloxy] salicylic acid zinc, 5- [p- (2-p-methoxyphenoxyethoxy) Cumyl] zinc salicylate, diphenylsulfone cross-linked compound represented by the following general formula (1), and the like. These materials may be added in an amount that does not impair the quality of the present invention. The content is not particularly limited, but usually it is preferably less than 50% by mass with respect to the total amount of the specific developer in the present invention.

（式中、ｎは１〜６の整数を表す。）

(In the formula, n represents an integer of 1 to 6.)

  The heat-sensitive recording layer may contain a storability improving agent. Thereby, the storage stability of a recording part can be improved. Specific examples of such preservability improvers include, for example, 2,2′-ethylidenebis (4,6-di-tert-butylphenol), 4,4′-thiobis (2-methyl-6-tert-butylphenol), 1 1,1,3-tris (2-methyl-4-hydroxy-5-tert-butylphenyl) butane, 1,1,3-tris (2-methyl-4-hydroxy-5-cyclohexylphenyl) butane, 2,2 Hindered phenol compounds such as bis (4-hydroxy-3,5-dimethylphenyl) propane, 4,4′-diglycidyloxydiphenylsulfone, 4-benzyloxy-4 ′-(2-methylglycidyloxy) diphenylsulfone , Diglycidyl terephthalate, cresol novolac epoxy resin, phenol novolac epoxy resin, vinyl Epoxy compounds such as bisphenol A type epoxy resin, N, N'-di-2-naphthyl -p- phenylenediamine, bis (4-ethylene iminocarbonyl aminophenyl) include methane and the like.

  Although the content rate of a preservability improving agent is not specifically limited, About 1-30 mass% is preferable in the total solid of a thermosensitive recording layer, and about 5-20 mass% is more preferable.

  In the present invention, an N-substituted fatty acid amide, which is an amide having a substituent on a nitrogen atom, is contained as a sensitizer among fatty acid amides. N-substituted fatty acid amides include N- [2- (3-phenylureido) phenyl] benzenesulfonamide, 4-hydroxy-4′-n-propoxydiphenylsulfone, and 4-color developer used in the present invention. The color developability with at least one selected from the group consisting of hydroxy-4′-allyloxydiphenylsulfone is good, and the effect of suppressing desensitization is excellent. Moreover, it is possible to obtain a quality excellent in heat-resistant texture fogging. As a result, after the heat-sensitive recording linerless label is finished, good color development performance is maintained even if it is placed in a high temperature and high humidity environment for a long period of time. Heat resistance at ℃ can be applied to suppress background fogging. The melting point of the N-substituted fatty acid amide is not particularly limited, but is preferably in the range of 110 to 160 ° C, more preferably in the range of 125 to 160 ° C. The content is not particularly limited, but is preferably about 1 to 40% by mass, more preferably about 2 to 30% by mass, and still more preferably about 3 to 25% by mass in the total solid content of the thermosensitive recording layer.

  Specific examples of N-substituted fatty acid amides include N, N'-ethylenebislauric acid amide, N, N'-methylbisstearic acid amide, N, N'-ethylenebisstearic acid amide, N, N'-ethylene. Bisoleic acid amide, N, N′-ethylenebehenic acid amide, N, N′-ethylenebis-12 hydroxystearic acid amide, N, N′-butylene bisstearic acid amide, N, N′-hexamethylenebisstearic acid Amide, N, N'-hexamethylenebisoleic acid amide, N, N'-xylylenebisstearic acid amide, stearic acid monomethylol amide, N, N'-dioleyl adipic acid amide, N, N'-distearyl Adipic acid amide, N, N′-distearyl sebacic acid amide, N, N′-distearyl terephthalic acid amide, N , N'-distearylisotalic acid amide and the like.

  Examples of other sensitizers include stearamide, dibenzyl terephthalate, benzyl p-benzyloxybenzoate, 2-naphthylbenzyl ether, m-terphenyl, p-benzylbiphenyl, p-tolylbiphenyl ether, di (p- Methoxyphenoxyethyl) ether, 1,2-di (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-acetoluidide, p-acetophenetide, N-acetoacetyl-p-tolui , Di (β-biphenylethoxy) benzene, oxalic acid di-p-chlorobenzyl ester, oxalic acid di-p-methylbenzyl ester, oxalic acid dibenzyl ester, and the like. You may add the quantity of the grade which does not inhibit the quality of. The content is not particularly limited, but it is usually preferably less than 50% by mass with respect to the total amount of the specific sensitizer in the present invention.

The heat-sensitive recording layer uses water as a dispersion medium, and is mixed with a dye precursor, a developer and a sensitizer, if necessary together with a preservability improver, or separately by a stirrer / pulverizer such as a ball mill, an attritor or a sand mill. After finely dispersing so that the particle diameter is 2 μm or less, a heat-sensitive recording layer coating solution prepared by adding an aqueous adhesive or the like is applied to one side of the support and dried. The aqueous adhesive in the heat-sensitive recording layer preferably contains at least one selected from the group consisting of acetoacetyl-modified polyvinyl alcohol, diacetone-modified polyvinyl alcohol, carboxy-modified polyvinyl alcohol, and silicon-modified polyvinyl alcohol. The heat-sensitive recording layer is formed by coating and drying on the support so that the dry weight is preferably about ² to 12 g / m ² , more preferably about ² to 6 g / m ² .

  Furthermore, various auxiliary agents can be contained in the heat-sensitive recording layer as necessary. Examples of auxiliary agents include kaolin, light calcium carbonate, heavy calcium carbonate, calcined kaolin, titanium oxide, magnesium carbonate, aluminum hydroxide, amorphous silica, urea / formalin resin filler and other pigments, sodium dioctylsulfosuccinate, dodecylbenzene. Dispersants such as sodium sulfonate, sodium lauryl alcohol sulfate, fatty acid metal salts, zinc stearate, calcium stearate, polyethylene wax, carnauba wax, paraffin wax, ester wax, hydrazine compounds, glyoxal, boric acid, dialdehyde Water resistant agents such as starch, methylol urea, glyoxylate, and epoxy compounds, antifoaming agents, colored dyes, fluorescent dyes and the like can be mentioned.

  The support used in the heat-sensitive recording material of the present invention is not particularly limited. For example, paper support such as neutral paper such as high-quality paper or acid paper, synthetic paper, transparent or translucent plastic film, white paper A plastic film etc. are mentioned. In addition, although the thickness of a support body is not specifically limited, Usually, it is about 20-200 micrometers.

  In the present invention, an undercoat layer can be provided between the support and the thermosensitive recording layer, if necessary. Thereby, the recording sensitivity and the recording running property can be further improved. The undercoat layer has an oil absorption amount of 70 ml / 100 g or more, in particular, about 80 to 150 ml / 100 g of an oil-absorbing pigment and / or organic hollow particles and / or thermally expandable particles, and an undercoat layer coating solution containing an adhesive as a main component. Is coated on a support and dried. Here, the oil absorption is a value determined according to the method of JIS K 5101.

  Various types of oil-absorbing pigments can be used. Specific examples include inorganic pigments such as calcined kaolin, amorphous silica, light calcium carbonate, and talc. The average particle diameter of the primary particles of these oil-absorbing pigments is preferably about 0.01 to 5 μm, more preferably about 0.02 to 3 μm. The amount of the oil-absorbing pigment used can be selected from a wide range, but is generally preferably about 2 to 95% by mass and more preferably about 5 to 90% by mass in the total solid content of the undercoat layer.

  In the present invention, a back layer comprising a pigment and a binder as main components can be provided on the surface of the support opposite to the thermosensitive recording layer, if necessary. As a result, the storage stability can be further improved, and the curl aptitude and the printer runnability can be improved.

  Examples of methods for forming each layer on the support include air knife method, blade method, gravure method, roll coater method, spray method, dipping method, bar method, curtain method, slot die method, slide die method, and extrusion method. Either a known coating method or a printing press method may be used.

  It is possible to perform a smoothing process using a super calender or the like in an arbitrary process after the formation of each layer or after the formation of all the layers. Various known techniques in the heat-sensitive recording material production field can be added as necessary.

  The present invention relates to a support, a heat-sensitive recording layer containing a dye precursor, a developer and a sensitizer from one side close to the support, a protective layer containing an adhesive, and a release on one side of the support. A thermosensitive recording linerless label having a layer and an adhesive layer on the other side of the support, wherein N- [2- (3-phenylureido) phenyl] benzenesulfonamide as a developer, Contains at least one selected from the group consisting of 4-hydroxy-4′-n-propoxydiphenylsulfone and 4-hydroxy-4′-allyloxydiphenylsulfone, and contains an N-substituted fatty acid amide as a sensitizer. The step of forming a heat-sensitive recording layer on one side of the support using the coating liquid for the heat-sensitive recording layer, and the formation of the pressure-sensitive adhesive layer on the other side of the support using the coating liquid for the pressure-sensitive adhesive layer containing the pressure-sensitive adhesive Including the process of A method for producing a thermosensitive recording linerless labels to symptoms. Thereby, even if the coating liquid penetrates into the support, or even when the front and back of the support are overlapped in the wound state, there is no fear that the components in the layer will diffuse and cause glue desensitization.

  The present invention will be described in more detail with reference to examples, but the present invention is not limited thereto. Unless otherwise specified, “part” and “%” indicate “part by mass” and “% by mass”, respectively.

Example 1
-Preparation of undercoat layer coating solution Fine hollow particles (trade name: Ropaque SN-1055) were dispersed in a dispersion obtained by dispersing 60 parts of calcined kaolin (trade name: Ansilex 93, manufactured by BASF) in 80 parts of water. , 75 parts by Dow Chemical Co., Ltd., solid content concentration 26.5%), 31 parts styrene / butadiene latex (trade name: L-1571, solid content concentration 48% by Asahi Kasei Chemicals), and carboxymethyl cellulose (trade name) : Serogen 7A, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) 2.5 parts, similarly carboxymethylcellulose (trade name: Serogen AG gum, Daiichi Kogyo Seiyaku Co., Ltd.) 1 part, and 95.5 parts of water are mixed and stirred to undercoat. A layer coating solution was obtained.

-Preparation of leuco dye dispersion liquid A composition comprising 10 parts of 3-di- (n-butyl) amino-6-methyl-7-anilinofluorane, 5 parts of a 5% aqueous solution of methylcellulose and 15 parts of water was obtained with a sand mill. A leuco dye dispersion (hereinafter also referred to as A liquid) was obtained by pulverizing until a median diameter of 0.5 μm by a laser diffraction particle size distribution analyzer SALD-2200 (manufactured by Shimadzu Corporation).

-Preparation of developer dispersion 10 parts of N- [2- (3-phenylureido) phenyl] benzenesulfonamide (trade name: NKK-1304, manufactured by Nippon Soda Co., Ltd.), 5 parts of a 5% aqueous solution of methylcellulose, and water 15 The composition consisting of parts is pulverized with a sand mill using a laser diffraction particle size distribution analyzer SALD-2200 (manufactured by Shimadzu Corporation) until the median diameter becomes 1.5 μm, and a developer dispersion (hereinafter referred to as B solution) Also called).

-Preparation of sensitizer dispersion liquid: 10 parts of N, N'-ethylenebisstearic acid amide (trade name: SLIPAX E, Nippon Kasei Co., Ltd., melting point 145 ° C), 5 parts of 5% aqueous solution of methylcellulose and 15 parts of water. The composition is pulverized by a sand mill with a laser diffraction particle size distribution analyzer SALD-2200 (manufactured by Shimadzu Corporation) until the median diameter becomes 1.0 μm, and a sensitizer dispersion (hereinafter also referred to as “C solution”). Got.

-Preparation of coating solution for heat-sensitive recording layer A solution 33.5 parts, solution B 68 parts, solution C 10.5 parts, fully saponified polyvinyl alcohol (trade name: PVA110, saponification degree: 99 mol%, average polymerization degree: 1000) 30 parts of a 10% aqueous solution of Kuraray Co., Ltd., 5 parts of a 20% aqueous solution of partially saponified polyvinyl alcohol (trade name: PVA205, degree of saponification: 88 mol%, average degree of polymerization: 500, made by Kuraray Co., Ltd.), butadiene copolymer Combined latex (trade name: P-OY72, manufactured by Japan A & L, solid concentration 48%) 16.5 parts, light calcium carbonate (trade name: Brilliant-15, manufactured by Shiroishi Kogyo Co., Ltd.) 46.8 parts, paraffin wax emulsion (Product name: Hydrin L-700, manufactured by Chukyo Yushi Co., Ltd., solid content concentration 30%) 10 parts and 90.5 parts of water were mixed and stirred to obtain a thermal recording layer coating solution.

Preparation of coating solution for protective layer Acetoacetyl-modified polyvinyl alcohol A (trade name: Gohsenx Z-200, degree of saponification: 99.4 mol%, average degree of polymerization: 1000, degree of modification: 5 mol%, Nippon Synthetic Chemical Industry Co., Ltd. 210 parts of an aqueous solution of 10% aqueous solution of acetoacetyl-modified polyvinyl alcohol B (trade name: Gohsenx Z-100, degree of saponification: 99.4 mol%, average degree of polymerization: 500, degree of modification: 5 mol%, Nippon Synthetic Chemical Industry) 80 parts of 20% aqueous solution, 58.5 parts of kaolin (trade name: HYDRAGLOSS 90, manufactured by KaMin LLC), 4 parts of aluminum hydroxide (trade name: Heidilite H-42M, manufactured by Showa Denko KK), glyoxylic acid A composition comprising 5 parts of a 10% aqueous solution of sodium (trade name: SPM-01, manufactured by Nippon Synthetic Chemical Industry) and 53 parts of water is mixed and stirred. To obtain a protective layer coating solution was adjusted to a pH5 with 10% aqueous acetic acid.

-Preparation of thermal recording material The coating amount after drying the coating solution for the undercoat layer, the coating solution for the thermal recording layer, and the coating solution for the protective layer on one surface of a high-quality paper having a basis weight of 60 g / m ² as a support. each 6.0 g ^{/ m} 2, was coated and dried by a curtain method so that 3.5 g / ^{m 2,} and 2.0 g / ^{m 2,} the undercoating layer, thermosensitive recording layer, and after sequentially forming a protective layer The surface was smoothed with a super calendar to obtain a heat-sensitive recording material.

-Formation of release layer 100 parts of solvent-free ultraviolet curable silicone compound (trade name: UV-271, manufactured by Arakawa Chemical Co., Ltd.), photopolymerization initiator (trade name: CATA 211, boron-based cationic curing catalyst, manufactured by Arakawa Chemical Co., Ltd.) The release layer coating solution obtained by mixing and stirring 5 parts was applied on the protective layer with a printing machine so that the coating amount after drying was 0.35 g / m ^2, and then irradiated with ultraviolet rays to form a release layer.

-Formation of pressure-sensitive adhesive layer Amount of coating after drying an aqueous emulsion acrylic emulsion pressure-sensitive adhesive (trade name: L-145, manufactured by Nippon Carbide Industries Co., Ltd.) as a coating liquid for the pressure-sensitive adhesive layer on the other surface of the support Was applied and dried by a roll coater method so as to be 25 g / m ² to form a pressure-sensitive adhesive layer, and then a wound thermal recording linerless label was obtained.

Example 2
Instead of N- [2- (3-phenylureido) phenyl] benzenesulfonamide in the preparation of the developer dispersion of Example 1, 4-hydroxy-4′-n-propoxydiphenylsulfone (trade name: Tomirac) A heat-sensitive recording linerless label was obtained in the same manner as in Example 1 except that KN (manufactured by API Corporation) was used.

Example 3
In the preparation of the sensitizer dispersion of Example 1, N, N′-ethylenebisstearic acid amide instead of N, N′-ethylenebisstearic acid amide (trade name: SLIPAX O, Nippon Kasei Co., Ltd., melting point) A thermal recording linerless label was obtained in the same manner as in Example 1 except that 119 ° C. was used.

Example 4
In the preparation of the sensitizer dispersion of Example 2, N, N′-ethylenebisstearic acid amide (trade name: SLIPAX O, manufactured by Nippon Kasei Co., Ltd., melting point) was used instead of N, N′-ethylenebisstearic acid amide. A heat-sensitive recording linerless label was obtained in the same manner as in Example 2 except that 119 ° C. was used.

Example 5
In the preparation of the sensitizer dispersion of Example 1, instead of N, N′-ethylenebisstearic acid amide, N, N′-xylylene bisstearic acid amide (trade name: SLIPAX PXS, manufactured by Nippon Kasei Co., Ltd., A thermal recording linerless label was obtained in the same manner as in Example 1 except that the melting point was 123 ° C.

Example 6
In the preparation of the sensitizer dispersion of Example 2, instead of N, N′-ethylenebisstearic acid amide, N, N′-xylylene bisstearic acid amide (trade name: SLIPAX PXS, manufactured by Nippon Kasei Co., Ltd., A thermal recording linerless label was obtained in the same manner as in Example 2 except that the melting point was 123 ° C.

Example 7
In the preparation of the sensitizer dispersion liquid of Example 1, instead of N, N′-ethylenebisstearic acid amide, N, N′-hexamethylenebisstearic acid amide (trade name: SLIPAX ZHS, manufactured by Nippon Kasei Co., Ltd., A thermal recording linerless label was obtained in the same manner as in Example 1 except that the melting point was 140 ° C.

Example 8
In the preparation of the sensitizer dispersion liquid of Example 2, instead of N, N′-ethylenebisstearic acid amide, N, N′-hexamethylenebisstearic acid amide (trade name: SLIPAX ZHS, manufactured by Nippon Kasei Co., Ltd., A heat-sensitive recording linerless label was obtained in the same manner as in Example 2 except that the melting point was 140 ° C.

Example 9
In the preparation of the sensitizer dispersion liquid of Example 1, instead of N, N′-ethylenebisstearic acid amide, N, N′-distearyl adipic acid amide (trade name: SLIPAX ZSS, manufactured by Nippon Kasei Co., Ltd., A heat-sensitive recording linerless label was obtained in the same manner as in Example 1 except that the melting point was 141 ° C.

Example 10
In the preparation of the sensitizer dispersion liquid of Example 2, instead of N, N′-ethylenebisstearic acid amide, N, N′-distearyl adipic acid amide (trade name: SLIPAX ZSS, manufactured by Nippon Kasei Co., Ltd., A thermal recording linerless label was obtained in the same manner as in Example 2 except that the melting point was 141 ° C.

Example 11
In preparation of the coating liquid for protective layer of Example 1, instead of acetoacetyl-modified polyvinyl alcohol A and acetoacetyl-modified polyvinyl alcohol B, 17 of diacetone-modified polyvinyl alcohol (trade name: DF-10, manufactured by Nippon Synthetic Chemical Co., Ltd.) A heat-sensitive recording linerless label was obtained in the same manner as in Example 1 except that 290 parts of a 6% aqueous solution was used.

Example 12
In the preparation of the protective layer coating solution of Example 1, instead of acetoacetyl-modified polyvinyl alcohol A and acetoacetyl-modified polyvinyl alcohol B, a 12% aqueous solution of silicon-modified polyvinyl alcohol (trade name: R-1130, manufactured by Kuraray Co., Ltd.) A thermal recording linerless label was obtained in the same manner as in Example 1 except that 308 parts were used.

Example 13
Instead of N- [2- (3-phenylureido) phenyl] benzenesulfonamide in the preparation of the developer dispersion of Example 1, 4-hydroxy-4′-allylacidiphenylsulfone (trade name: BPS- A thermal recording linerless label was obtained in the same manner as in Example 1 except that MAE (manufactured by Nikka Chemical Co., Ltd.) was used.

Comparative Example 1
In the preparation of the developer dispersion of Example 1, 4-hydroxy-4′-isoproxydiphenylsulfone was used in place of N- [2- (3-phenylureido) phenyl] benzenesulfonamide, and sensitization was performed. Example 1 except that di-p-methylbenzyl oxalate (trade name: HS3520, manufactured by DIC) was used in place of N, N′-ethylenebisstearic acid amide in the preparation of the agent dispersion. Similarly, a thermal recording linerless label was obtained.

Comparative Example 2
In the preparation of the developer dispersion of Example 1, except that 4-hydroxy-4′-isoproxydiphenylsulfone was used instead of N- [2- (3-phenylureido) phenyl] benzenesulfonamide, A thermal recording linerless label was obtained in the same manner as in Example 1.

Comparative Example 3
In the preparation of the sensitizer dispersion of Example 1, oxalic acid di-p-methylbenzyl ester (trade name: HS3520, manufactured by DIC) was used instead of N, N′-ethylenebisstearic acid amide. Obtained a thermal recording linerless label in the same manner as in Example 1.

Comparative Example 4
In the preparation of the sensitizer dispersion of Example 2, oxalic acid di-p-methylbenzyl ester (trade name: HS3520, manufactured by DIC) was used in place of N, N′-ethylenebisstearic acid amide. Obtained a thermal recording linerless label in the same manner as in Example 2.

Comparative Example 5
In the preparation of the sensitizer dispersion of Example 2, stearamide (trade name: Amide AP-1, Nippon Kasei Co., Ltd., melting point: 101 ° C.) was used instead of N, N′-ethylenebisstearic acid amide. A heat-sensitive recording linerless label was obtained in the same manner as in Example 2 except that.

  The thermal recording linerless label thus obtained was allowed to stand for 24 hours in an environment of 40 ° C. and 50% RH, and then evaluated as follows. The results were as shown in Table 1.

Recording density Using a thermal recording evaluation machine (trade name: TH-PMD, manufactured by Okura Electric Co., Ltd.), recording was performed at an applied energy of 0.24 mJ / dot. The reflection density of the obtained printed part was measured in a visual mode of a Macbeth densitometer (RD-914, manufactured by Macbeth). The recording density is preferably 1.30 or more for practical use.

-White paper storage stability Each thermal recording linerless label was stored in an environment of 40 ° C. and 90% RH for 7 days, and then recorded in the same manner as in the evaluation of the recording density, and the reflection density was measured. The recording density is preferably as close as possible to the above-mentioned recording density recorded and measured before storage.

-Heat resistance The thermal recording linerless label before recording was allowed to stand at 90 ° C for 1 hour, and then the reflection density of the blank paper portion was measured in the same manner with a Macbeth densitometer (described above). The reflection density is preferably 0.20 or less.

・ Plasticizer resistance A wrap film (trade name: High Wrap KMA-W, manufactured by Mitsui Chemicals) is wrapped around a polycarbonate pipe (40 mm diameter) in a triple layer, and thermal recording after recording in recording density evaluation is performed on the film. Place the linerless label, wrap the wrap film in three layers on it, leave it at 40 ° C for 24 hours, peel off the wrap film, and check the reflection density of the printed part in the Macbeth densitometer (described above) visual mode. It was measured. The recording density after the treatment is preferably 1.00 or more for practical use.

Claims (5)

  A support, a thermosensitive recording layer containing a dye precursor, a developer and a sensitizer from the side close to the support, a protective layer containing an adhesive, and a release layer on one side of the support. And a thermal recording linerless label having an adhesive layer on the other surface of the support, wherein the developer is N- [2- (3-phenylureido) phenyl] benzenesulfonamide, 4-hydroxy Containing at least one selected from the group consisting of -4'-n-propoxydiphenylsulfone and 4-hydroxy-4'-allyloxydiphenylsulfone, and containing an N-substituted fatty acid amide as the sensitizer. Characteristic thermal recording linerless label.   The thermal recording linerless label according to claim 1, wherein the N-substituted fatty acid amide has a melting point in the range of 110 to 160 ° C.   The adhesive contained in the protective layer is at least one selected from the group consisting of acetoacetyl-modified polyvinyl alcohol, diacetone-modified polyvinyl alcohol, carboxy-modified polyvinyl alcohol, and silicon-modified polyvinyl alcohol. Thermal recording linerless label as described.   The heat-sensitive recording linerless label according to any one of claims 1 to 3, wherein the pressure-sensitive adhesive layer comprises a water-based pressure-sensitive adhesive.   A support, a thermosensitive recording layer containing a dye precursor, a developer and a sensitizer from the side close to the support, a protective layer containing an adhesive, and a release layer on one side of the support. And a method for producing a thermosensitive recording linerless label having an adhesive layer on the other surface of the support, wherein the developer is N- [2- (3-phenylureido) phenyl] benzenesulfonamide, 4 Containing at least one selected from the group consisting of -hydroxy-4'-n-propoxydiphenylsulfone and 4-hydroxy-4'-allyloxydiphenylsulfone, and containing an N-substituted fatty acid amide as the sensitizer. The step of forming a heat-sensitive recording layer on one side of the support using the coating liquid for the heat-sensitive recording layer, and the formation of the pressure-sensitive adhesive layer on the other side of the support using the coating liquid for the pressure-sensitive adhesive layer containing the pressure-sensitive adhesive Including the process of Method for producing a thermosensitive recording linerless labels characterized by and.