JP2017177351A - 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 the occurrence of printing blur and suppresses the occurrence of scratches on the printed surface, and to provide a method for manufacturing the thermosensitive recording linerless label.SOLUTION: The thermosensitive recording linerless label has a support, a thermosensitive recording layer containing a dye precursor, a developer, and an aqueous adhesive, a protective layer containing an aqueous 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 spherical organic particles having an average particle size of 2.0 to 13 μm in the thermosensitive recording layer.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 thermal recording pressure-sensitive adhesive sheet increases due to the configuration of the pressure-sensitive adhesive layer and release paper, the length of the thermal recording pressure-sensitive 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, if the adhesive strength between the protective layer of the thermal recording material and the release layer is weak, the release layer may be peeled off due to the thermal energy of the thermal head, and printing problems may occur. There is a problem that a part of the adhesive adheres to the pressure-sensitive adhesive layer and the adhesiveness is lowered. In addition, a thermal recording linerless label has been proposed in which the protective layer on the thermal recording layer contains crosslinked polymethyl methacrylate particles having a volume average particle size of 1.0 μm to 8.0 μm (Patent Document 5). However, there is a problem that the barrier property of the protective layer is lowered and the resistance to plasticizers, oils, alcohols and the like is lowered.

  In other words, thermal recording linerless labels that do not use release paper have not sufficiently solved printing problems such as sticking and head wrinkles derived from adhesives and release agents, and are far more than conventional labels that use release paper. Strict quality is required. In other words, unlike conventional labels having release paper, the thermal recording linerless label is a pressure-sensitive adhesive that has the release layer on the recording surface side scraped off or stored in a wound form and the front and back are in close contact and transferred to the release layer surface. There is a problem that the agent layer is peeled off to form a head wrinkle. The head wrinkle causes a scratch on the recording surface, accumulates and inhibits heat transfer to the recording surface, and causes a print blur. 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

  The main object of the present invention is to provide a heat-sensitive recording linerless label and a method for producing the same, which are free from print shading and suppress the occurrence of scratches on the print surface.

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

  Item 1: A support, a thermal recording layer containing a dye precursor, a developer and a water-based adhesive, a protective layer containing a water-based adhesive, and a release layer on one side of the support from the side close to the support A heat-sensitive recording linerless label having an adhesive layer on the other surface, wherein the heat-sensitive recording layer contains spherical organic particles having an average particle diameter of 2.0 to 13 μm. Record linerless label.

  Item 2: The heat-sensitive recording linerless label according to item 1, wherein the heat-sensitive recording layer has an average thickness of 2 to 6 μm and a protective layer has an average thickness of 1 to 4 μm.

  Item 3: The aqueous 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, silicon-modified polyvinyl alcohol, and methacrylonitrile-based copolymers. Item 3. The thermal recording linerless label according to Item 1 or 2, which is a seed.

  Item 4: The methacrylonitrile copolymer is a copolymer comprising a monomer containing (i) methacrylonitrile and (ii) a vinyl monomer copolymerizable with methacrylonitrile, wherein the vinyl monomer Item 3. The body (ii) contains at least one carboxyl group-containing vinyl monomer, and the content of the carboxyl group-containing vinyl monomer is 1 to 10% by mass in the monomer. Thermal recording linerless label as described.

  Item 5: The heat-sensitive recording according to any one of Items 1 to 4, wherein the heat-sensitive recording layer contains one selected from the group consisting of fully saponified polyvinyl alcohol, partially saponified polyvinyl alcohol, and butadiene copolymer latex. Linerless label.

  Item 6: The thermal recording linerless label according to any one of Items 1 to 5, wherein an average thickness of the thermal recording layer is smaller than or equal to an average particle diameter of the spherical organic particles.

  Item 7: A support, a heat-sensitive recording layer containing a dye precursor and a developer, a protective layer containing a water-based adhesive, and a release layer are provided on one side of the support from the side close to the support, A method for producing a thermosensitive recording linerless label in which an adhesive layer is provided on the surface of the thermosensitive recording layer, wherein the thermosensitive recording layer is formed using a coating solution for thermosensitive recording layers containing spherical organic particles having an average particle diameter of 2.0 to 13 μm. A process for producing a thermal recording linerless label, comprising the step of:

  The heat-sensitive recording linerless label of the present invention is free from deposits due to deposits on the thermal head heating element, so-called head wrinkles, even when used under severe conditions such as distribution management, and the print surface is not damaged. Occurrence can be suppressed. Moreover, front and back blocking can be suppressed.

  In the present invention, a thermal recording layer containing a dye precursor, a developer and an aqueous adhesive is provided on one surface of the support. The thermosensitive recording layer further contains spherical organic particles having an average particle size of 2.0 to 13 μm. By including such particles in the heat-sensitive recording layer, it is possible to suppress the occurrence of print blurring and scratches due to the head wrinkles even if the adhesion between the protective layer and the release layer is not sufficient. Further, even if a head wrinkle occurs, it can be scraped off during printing and removed, so that it is possible to suppress the occurrence of print scrapes and scratches. Furthermore, blocking of the front and back sides can be suppressed in the winding state, and heavy peeling or conversely light peeling can be suppressed, and the peeling force can be stabilized.

  In the present invention, if the average particle diameter of the spherical organic particles is smaller than 2.0 μm, the head wrinkles cannot be sufficiently removed. On the other hand, if it is larger than 13 μm, heat transfer from the thermal head to the recording surface and heat transfer from the recording surface to the thermal recording layer are hindered, resulting in white spots in the recorded image. Further, the spherical organic particles themselves may fall off and cause head wrinkles. The average particle diameter of the spherical organic particles is preferably about 2.5 to 10 μm, more preferably about 3 to 8 μm, and still more preferably about 5 to 8 μm. As a result, it is possible to effectively suppress printing blurring and scratches regardless of the printing rate. In the present invention, the average particle diameter is an average of 100 particles measured by taking a cross-sectional photograph of the heat-sensitive recording layer with an electron microscope, assuming that the photographed particles are spherical with an approximate area, and calculating the particle diameter. It can be determined as the particle size. The average particle diameter can also be determined by measurement using a laser diffraction / scattering method or a dynamic light scattering method. For example, a laser diffraction particle size distribution analyzer SALD-2200 (manufactured by Shimadzu Corporation) can be used. In any case, the effects of the present invention can be exhibited without regret by setting the average particle diameter within a specific range.

  In the present invention, the content ratio of the spherical organic particles is not particularly limited, but is preferably about 0.5 to 10% by mass in the total solid content of the heat-sensitive recording layer. By setting the content to 0.5% by mass or more, it is possible to effectively suppress the occurrence of printing blur and scratches. On the other hand, when the content is 10% by mass or less, the recording density can be increased and the oil resistance and plasticizer resistance can be improved. Such a content is preferably about 4 to 10% by mass, more preferably about 5 to 8% by mass, from the viewpoint of effectively suppressing print scrapes and scratches regardless of the printing rate.

  The average thickness of the heat-sensitive recording layer in the present invention is 2 to 6 μm, and more preferably about 2 to 4 μm. The average thickness of the protective layer is 1 to 4 μm, and more preferably about 1 to 3 μm. By adjusting within this range, the thermal recording layer melts and softens due to the pressure and heat of the thermal head during recording to exhibit cushioning properties, while the spherical organic particles in the thermal recording layer exhibit hardness. The head wrinkles can be effectively removed. Further, by making the average thickness of the heat-sensitive recording layer smaller than or the same as the average particle diameter of the spherical organic particles in the heat-sensitive recording layer, the effect of removing the head wrinkles can be remarkably improved. The average thickness of the thermosensitive recording layer is measured by taking a cross-sectional photograph with an electron microscope.

  The spherical organic particles used in the present invention are selected from chemical compositions such as styrene, acrylic, benzoguanamine, nylon, phenol, epoxy, silicone, and fluorine. Production methods include polymerization from monomers, chemical treatment of polymers (dissolution precipitation method, crystallization method, post-emulsification method, etc.), mechanical pulverization method, etc. The spherical organic particles used in the present invention are Since the effect of the present invention is further enhanced when the particle size distribution is sharp, those produced by a polymerization method or a chemical treatment method are preferred. With the mechanical pulverization method, it is difficult to obtain fine particles, and since the particle size distribution is broad and the shape is indefinite, it is difficult to obtain the effects of the present invention. In addition, the spherical organic particles can be improved in heat resistance by having a three-dimensional crosslinked structure. The sphericity of the spherical resin particles in the thermosensitive recording layer is not particularly limited, but may be 0.7 or more.

  In this invention, it is preferable that spherical organic particle is at least 1 sort (s) consisting of the group which consists of a polymethyl methacrylate type crosslinked material and a benzoguanamine type crosslinked material. Thereby, the effect of exhibiting hardness and removing the head wrinkles can be enhanced.

  Examples of the thermosensitive recording system having an electron donating compound and an electron accepting compound include a combination of a leuco dye as a dye precursor and a developer, a combination of a diazonium salt and a coupler, a transition element such as iron, cobalt, and copper. A combination with a chelate compound, a combination of an aromatic isocyanate compound and an imino compound, and the like can be mentioned, but a combination of a leuco dye and a developer is preferably used because of excellent color density. Hereinafter, the heat-sensitive recording layer comprising a combination of a leuco dye and a developer will be described in detail.

  Various known leuco dyes and developers can be 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 ratio of the leuco dye may be appropriately selected depending on the developer to be used, and is not particularly limited, but is preferably about 3 to 50% by mass, more preferably 5 to 40% in the total solid content of the heat-sensitive recording layer. It is about mass%.

  Examples of the developer include 4,4′-isopropylidenediphenol, 4,4′-cyclohexylidenediphenyl, 1,1-bis (4-hydroxyphenyl) -ethane, 1,1-bis (4-hydroxy). Phenyl) -1-phenylethane, 4,4′-dihydroxydiphenylsulfone, 2,4′-dihydroxydiphenylsulfone, 4-hydroxy-4′-isopropoxydiphenylsulfone, 4-hydroxy-4′-allyloxydiphenylsulfone, 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-phen Xoxycarbonylaminophenyl) ureido] diphenylsulfone, 4-hydroxybenzoic acid benzyl ester, N, N′-di-m-chlorophenylthiourea, Np-tolylsulfonyl-N′-phenylurea, 4,4′-bis (P-tolylsulfonylaminocarbonylamino) diphenylmethane, N- [2- (3-phenylureido) phenyl] benzenesulfonamide, 4- [2- (p-methoxyphenoxy) ethyloxy] zalicylic acid zinc, 4- {3- ( Examples include zinc p-tolylsulfonyl) propyloxy] salicylate, zinc 5- [p- (2-p-methoxyphenoxyethoxy) cumyl] salicylate, and a diphenylsulfone crosslinked compound represented by the following general formula (1).

（式中、ｎは１〜６の整数を表す。）

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

  The content ratio of the developer may be appropriately selected depending on the leuco dye to be used, and is not particularly limited, but is preferably about 10 to 70% by mass, more preferably 12 to 50% by mass in the total solid content of the heat-sensitive recording layer. Degree.

  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.

  The content ratio of the preservability improver may be an effective amount for improving the preservability, but usually, the total solid content of the heat-sensitive recording layer is preferably about 1 to 30% by mass, more preferably 5 to 5%. It is about 20% by mass.

  The heat-sensitive recording layer may contain a sensitizer. Thereby, the recording sensitivity can be increased. Specific examples of such sensitizers include, for example, stearamide, methylenebis 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-methoxy) Phenoxy) 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-aceto Enechijido, N- acetoacetyl -p- toluidine, di (beta-biphenyl ethoxy) benzene, oxalic acid di -p- chlorobenzyl ester, oxalic acid di -p- methylbenzyl ester, and the like oxalic acid dibenzyl ester.

  The content of the sensitizer may be an amount effective for sensitization, but is usually about 2 to 40% by mass, more preferably 5 to 25% by mass in the total solid content of the heat-sensitive recording layer. %.

  In the present invention, as the aqueous adhesive contained in the heat-sensitive recording layer, at least one of conventionally known water-soluble polymers and water-dispersible polymers can be appropriately used.

  Specific examples of water-soluble polymers include modified saponified polyvinyl alcohol, partially saponified polyvinyl alcohol, acetoacetyl-modified polyvinyl alcohol, diacetone-modified polyvinyl alcohol, carboxy-modified polyvinyl alcohol, silicon-modified polyvinyl alcohol, and itaconic acid-modified polyvinyl alcohol. Polyvinyl alcohol; starch such as starch and oxidized starch or derivatives thereof; cellulose derivatives such as hydroxymethylcellulose, hydroxyethylcellulose, carboxymethylcellulose, methylcellulose, and ethylcellulose; in addition, polyacrylic acid soda, polyvinylpyrrolidone, acrylamide-acrylic acid ester co-polymer Polymer, acrylamide-acrylic acid ester-methacrylic acid terpolymer, styrene-maleic anhydride copolymer Combined alkali salt of isobutylene - maleic anhydride copolymer alkali salts, polyacrylamide, sodium alginate, gelatin, gum arabic, casein and the like.

  Examples of water-dispersible polymers include polyvinyl acetate, polyurethane, polyacrylic acid, polyacrylic acid ester, vinyl chloride / vinyl acetate copolymer, polybutyl methacrylate, ethylene-vinyl acetate copolymer emulsions, and styrene-butadiene. Copolymers, styrene-butadiene-acrylic copolymers and the like can be mentioned, and these can also be used as dispersions (latex).

  These water-soluble polymers and water-dispersible polymers may be used alone or in combination of two or more.

  Among these water-soluble polymers and water-dispersible polymers, one kind selected from the group consisting of fully saponified polyvinyl alcohol, partially saponified polyvinyl alcohol and butadiene copolymer latex is selected from the viewpoint of suppressing the dropping of spherical organic particles. It is preferable to contain.

The heat-sensitive recording layer uses water as a dispersion medium, leuco dye, color developer, water adhesive, sensitizer, preservability improver, etc., if necessary, or separately, stirring and grinding with a ball mill, attritor, sand mill, etc. Supports a thermal recording layer coating solution prepared by mixing a dispersion liquid with an average particle size of 2 μm or less by a machine, water-based adhesive, specific spherical organic particles, and auxiliary agents if necessary. It is formed by applying and drying on one side of the body. 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 added to the thermal recording layer coating liquid as necessary. For example, kaolin, light (heavy) calcium carbonate, calcined kaolin, titanium oxide, magnesium carbonate, aluminum hydroxide, Amorphous silica, pigments such as urea / formalin resin filler, dispersants such as sodium dioctylsulfosuccinate, sodium dodecylbenzenesulfonate, sodium lauryl alcohol sulfate, fatty acid metal salt, zinc stearate, calcium stearate, polyethylene wax, carnauba wax, Waxes such as paraffin wax and ester wax, hydrazine compounds, glyoxal, boric acid, dialdehyde starch, methylolurea, glyoxylate, epoxy compounds and other water-resistant agents, antifoaming agents, coloring dyes and fluorescent dyes It is.

  In the present invention, a protective layer containing an aqueous adhesive is provided on the heat-sensitive recording layer. The aqueous 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, silicon-modified polyvinyl alcohol, and methacrylonitrile copolymer. It is preferable.

  The acetoacetyl-modified polyvinyl alcohol, diacetone-modified polyvinyl alcohol, carboxy-modified polyvinyl alcohol, and silicon-modified polyvinyl alcohol used in the protective layer are monomers having an acetoacetyl group, a diacetone group, a carboxyl group, and a silyl group, respectively. It is produced by saponifying a resin obtained by copolymerization with a vinyl ester.

  The degree of saponification is preferably about 85 mol% to 100 mol% of complete saponification, more preferably about 90 to 100 mol%. The average degree of polymerization is preferably about 300 to 3000, and more preferably about 400 to 2000. The degree of modification is preferably about 0.5 to 10 mol%, more preferably about 1 to 9 mol%. 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.

  If the degree of modification is in the range of about 0.5 to 10 mol%, sufficient water resistance is obtained, and the solubility in water does not decrease, so that the solution concentration can be prevented from being lowered.

  The methacrylonitrile-based copolymer is a copolymer comprising a monomer containing (i) methacrylonitrile and (ii) a vinyl monomer copolymerizable with methacrylonitrile, wherein the vinyl monomer (ii) is It is preferable that at least one carboxyl group-containing vinyl monomer is contained, and the content ratio of the carboxyl group-containing vinyl monomer is 1 to 10% by mass in the monomer. This is preferably used in the form of a resin emulsion. Such a resin emulsion of a copolymer can be produced, for example, according to a method disclosed in JP-A-2004-74531. This resin emulsion has good water resistance after drying the resin itself, does not require the addition of a curing agent, and is characterized by no problem in the pot life of a paint such as a combination of a modified polyvinyl alcohol and a curing agent. is there.

  The content ratio of at least one selected from the group consisting of acetoacetyl-modified polyvinyl alcohol, diacetone-modified polyvinyl alcohol, carboxy-modified polyvinyl alcohol, silicon-modified polyvinyl alcohol, and methacrylonitrile copolymer contained in the protective layer is particularly limited. However, it is preferably about 10 to 90% by mass, more preferably about 15 to 50% by mass in the total solid content of the protective layer.

  Other adhesives can be used in combination with the protective layer 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 can be mentioned.

  In the present invention, the protective layer may contain a pigment. The pigment is not particularly limited, and examples thereof include inorganic pigments such as calcium carbonate, zinc oxide, aluminum oxide, titanium dioxide, amorphous silica, aluminum hydroxide, barium sulfate, talc, kaolin, and calcined kaolin, and organic pigments. . Of these, kaolin and aluminum hydroxide are preferably used because they have a small decrease in barrier properties against chemicals such as plasticizers and oils and a small decrease in recording density. Moreover, you may contain spherical organic particle in the range which does not impair the effect of this invention.

  Examples of auxiliary agents that may be contained in the protective layer include lubricants such as zinc stearate, calcium stearate, carnauba wax, paraffin wax, ester wax, sodium alkylbenzene sulfonate, sodium dioctyl sulfosuccinate, sulfone-modified polyvinyl alcohol, 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. It is also possible to add auxiliary agents.

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

The thermal recording linerless label has a release layer on the protective layer. That is, the release layer is provided on the protective layer of the thermal recording body comprising at least the support, the thermal recording layer on the support, and the protective layer on the thermal recording layer. The silicone for release used in the release layer is roughly classified into a solvent type, a solventless type, and an emulsion type according to the form, and according to the difference in curing mode, it is roughly divided into a thermosetting type, an ultraviolet ray or an electron beam curable type, Since it is required that the environmental problem or the heat-sensitive recording layer does not develop color, it is preferable to use a coating solution for a release layer mainly composed of an ultraviolet ray 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 ultraviolet 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 cation derivatives. The coating amount of the release layer is not particularly limited, and is preferably adjusted in a range of about 0.05 to 3 g / m ² by dry weight.

The thermal recording linerless label has an adhesive layer on the other side of the support (the side opposite to the side provided with the thermal recording layer). Examples of the pressure-sensitive adhesive used in the present invention include those based on rubber-based materials such as natural rubber, styrene-butadiene rubber, polyisobutylene rubber, and isoprene rubber, and those based on vinyl ether-based materials. -The thing which has as a main component the copolymer which has ethylhexyl acrylate as a main monomer, and the thing which has rubbery siloxane and resinous siloxane as a main component are mentioned. These rubber-based, acrylic-based, urethane-based, and silicone-based pressure-sensitive adhesives can be used as emulsions, various solvents or solvent-free pressure-sensitive adhesives. The application amount of the pressure-sensitive adhesive layer is not particularly limited, and is preferably adjusted in the range of about 5 to 50 g / m ² by dry weight.

  Although it does not specifically limit as a support body used for this invention, For example, neutral or acidic high-quality paper, a synthetic paper, a transparent or translucent plastic film, a white 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, if necessary, an undercoat layer can be provided between the support and the heat-sensitive recording layer. 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, particularly 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.

  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.

  In addition, it is possible to perform a smoothing process such as super calendering in an arbitrary process after forming each layer, and various known techniques in the field of manufacturing a thermal recording material can be added as necessary. It is. In addition, processing such as printing and die cutting may be performed as a label.

  The present invention also provides a support, a heat-sensitive recording layer containing a dye precursor and a developer from the side close to the support, a protective layer containing a water-based adhesive, and a release layer on one side of the support. A method for producing a thermal recording linerless label provided with a pressure-sensitive adhesive layer on the other surface, using a thermal recording layer coating solution containing spherical organic particles having an average particle size of 2.0 to 13 μm. A method for producing a thermal recording linerless label, comprising the step of forming a layer. Thereby, blocking of the front and back in a winding state can be suppressed, and rolling-out can be smoothly performed.

  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 Company, solid content concentration 26.5%), 31 parts styrene-butadiene latex (trade name: L-1571, manufactured by Asahi Kasei Chemicals Corporation, solid content concentration 48%), 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 “liquid A”) was obtained by pulverizing until the median diameter was 0.5 μm using a laser diffraction particle size distribution analyzer SALD-2200 (manufactured by Shimadzu Corporation).

-Preparation of developer dispersion liquid A composition comprising 10 parts of 4-hydroxy-4'-isopropoxydiphenylsulfone, 5 parts of a 5% aqueous solution of methylcellulose and 15 parts of water was subjected to a laser diffraction particle size distribution analyzer SALD- using a sand mill. The developer was pulverized until the median diameter by 2200 (manufactured by Shimadzu Corporation) was 1.5 μm to obtain a developer dispersion (hereinafter also referred to as “B solution”).

-Preparation of developer dispersion liquid A composition comprising 10 parts of a diphenylsulfone cross-linking compound (trade name: D-90, manufactured by Nippon Soda Co., Ltd.), 5 parts of a 5% aqueous solution of methylcellulose and 15 parts of water was laser-diffracted with a sand mill. A developer dispersion (hereinafter, also referred to as “C solution”) was obtained by pulverizing until a median diameter of 1.0 μm was obtained using a particle size distribution analyzer SALD-2200 (manufactured by Shimadzu Corporation).

-Preparation of sensitizer dispersion liquid A composition comprising 10 parts of di-p-methylbenzyl oxalate, 5 parts of a 5% aqueous solution of methylcellulose and 15 parts of water was mixed with a laser diffraction particle size distribution analyzer SALD-2200 ( A sensitizer dispersion (hereinafter also referred to as D solution) was obtained by pulverizing until the median diameter by Shimadzu Corporation was 1.0 μm.

-Preparation of coating solution for heat-sensitive recording layer A solution 33.5 parts, solution B 68 parts, solution C 5 parts, solution D 10.5 parts, fully saponified polyvinyl alcohol (trade name: PVA110, saponification degree: 99 mol%, 30 parts of 10% aqueous solution of average degree of polymerization: 1000, manufactured by Kuraray Co., Ltd., 5 parts of 20% aqueous solution of partially saponified polyvinyl alcohol (trade name: PVA205, degree of saponification: 88 mol%, average degree of polymerization: 500, manufactured by Kuraray Co., Ltd.) , Butadiene copolymer 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.) 42.1 Parts, paraffin wax emulsion (trade name: Hydrin L-700, manufactured by Chukyo Yushi Co., Ltd., solid content concentration 30%), spherical organic particles (trade name: Eposta MA1006, average particle size) [mu] m, polymethyl methacrylate-based cross-linked product, Nippon Shokubai Kagaku Kogyo Co., Ltd.) 3 parts, and water 90.5 parts mixture 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.

- on one surface of woodfree paper having produced a basis weight of 60 g / m ² of the thermosensitive recording medium (the surface of the support), the undercoat layer coating liquid, heat-sensitive recording layer coating solution, and using a protective layer coating composition, the coating amount after drying of 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 protective After sequentially forming the layers, the surface was smoothed with a super calendar to obtain a heat-sensitive recording material.

Preparation of thermal recording linerless label 100 parts of solvent-free UV curable silicone compound (trade name: UV-271, manufactured by Arakawa Chemical Co., Ltd.), photopolymerization initiator (trade name: CATA 211, boron-based cationic curing catalyst, Arakawa Chemical) After applying 5 parts of the release layer coating solution mixed and stirred on the protective layer of the heat-sensitive recording medium with a printing machine so that the coating amount after drying was 0.35 g / m ² , ultraviolet rays were applied. Was applied to form a release layer.

Furthermore, a highly adhesive acrylic resin adhesive emulsion as a coating liquid for the adhesive layer is applied to the other surface (back surface of the support) of the high-quality recording paper on which the release layer is formed after drying by a roll coater method. The pressure-sensitive adhesive layer was formed by coating and drying so that the amount was 20 g / m ^2, and then a wound thermal recording linerless label was obtained.

Example 2
A heat-sensitive recording linerless label was obtained in the same manner as in Example 1 except that the amount of the spherical organic particles was changed to 5 parts instead of 3 parts in the preparation of the heat-sensitive recording layer coating liquid of Example 1.

Example 3
A thermal recording linerless label was obtained in the same manner as in Example 1 except that the amount of spherical organic particles was changed to 8 parts instead of 3 parts in the preparation of the thermal recording layer coating liquid of Example 1.

Example 4
In the preparation of the thermosensitive recording layer coating liquid of Example 1, the amount of spherical organic particles was changed to 3 parts to 5 parts, and the type was spherical organic particles (trade name: Eposta GP-50, average particle diameter 5 μm, benzoguanamine type). A heat-sensitive recording linerless label was obtained in the same manner as in Example 1 except that the product was changed to a crosslinked product (manufactured by Nippon Shokubai Chemical Industry Co., Ltd.).

Example 5
In the preparation of the heat-sensitive recording layer coating liquid of Example 1, the amount of spherical organic particles was changed to 5 parts to 5 parts, and the type was spherical organic particles (trade name: GM-0401S, average particle diameter 4 μm, polymethacrylic acid). A heat-sensitive recording linerless label was obtained in the same manner as in Example 1 except that it was changed to a methyl-based crosslinked product (manufactured by Ganz Kasei Co., Ltd.).

Example 6
In the preparation of the heat-sensitive recording layer coating liquid of Example 1, the amount of spherical organic particles was changed to 5 parts to 5 parts, and the type was spherical organic particles (trade name: GM-0801, average particle diameter 8 μm, polymethacrylic acid). A heat-sensitive recording linerless label was obtained in the same manner as in Example 1 except that it was changed to a methyl-based crosslinked product (manufactured by Ganz Kasei Co., Ltd.).

Example 7
In preparing the protective layer coating liquid of Example 1, instead of 210 parts of a 10% aqueous solution of acetoacetyl-modified polyvinyl alcohol A and 80 parts of a 20% aqueous solution of acetoacetyl-modified polyvinyl alcohol B, diacetone-modified polyvinyl alcohol ( A thermal recording linerless label was obtained in the same manner as in Example 1 except that 290 parts of a 17.6% aqueous solution (trade name: DF-10, manufactured by Nippon Synthetic Chemical Industry Co., Ltd.) was used.

Example 8
In the preparation of the coating solution for the protective layer of Example 1, 210 parts of 10% aqueous solution of acetoacetyl-modified polyvinyl alcohol A and 80 parts of 20% aqueous solution of acetoacetyl-modified polyvinyl alcohol B were used instead 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 of a 12% aqueous solution was used.

Example 9
-Preparation of coating solution for protective layer Copolymer resin (copolymerization component: (meth) acrylonitrile / (meth) acrylic acid alkyl / (meth) acrylic acid 2-hydroxyethyl / (meth) acrylic acid / (meth) acrylamide, ( Ratio of (meth) acrylic acid: 5% by mass with respect to the entire copolymer resin, solubility parameter: 12.8, glass transition temperature: 50 ° C., average particle size: 230 nm) (trade name: OT1043Z-1, solid content) Concentration 25%, Mitsui Chemicals, Inc.) 140 parts, Kaolin (trade name: HYDRAGLOSS 90, KaMin LLC) 200 parts, Aluminum hydroxide (trade name: Heidilite H-42M, Showa Denko) 47 parts, anionic Polyethylene wax emulsion (trade name: Meikax HP-598A, manufactured by Meisei Chemical Co., Ltd., solid content concentration 25 , Mp 100 ° C., to obtain particle size 0.04 .mu.m) 12 parts, and stirred together the protective layer coating solution composition comprising water 74.3 parts.

  A thermosensitive recording linerless label was obtained in the same manner as in Example 1 except that in the production of the thermosensitive recording material of Example 1, the above-described protective layer coating solution was used instead of the protective layer coating solution used.

Example 10
A thermosensitive recording linerless label was obtained in the same manner as in Example 9 except that the amount of spherical organic particles was changed to 5 parts instead of 3 parts in the production of the thermal recording layer coating liquid of Example 9.

Example 11
A heat-sensitive recording linerless label was obtained in the same manner as in Example 9 except that the amount of the spherical organic particles was changed to 8 parts instead of 3 parts in the production of the heat-sensitive recording layer coating liquid of Example 9.

Comparative Example 1
In the preparation of the thermal recording coating liquid of Example 1, a thermal recording linerless label was obtained in the same manner as in Example 1 except that 3 parts of the spherical organic particles were not used.

Comparative Example 2
In the preparation of the heat-sensitive recording layer coating liquid of Example 1, the amount of spherical organic particles was changed to 3 parts to 5 parts, and the type was spherical organic particles (trade name: Eposta MA1002, average particle size 1.5 μm, polymethacrylic acid). A heat-sensitive recording linerless label was obtained in the same manner as in Example 1 except that it was changed to a methyl acid cross-linked product (manufactured by Nippon Shokubai Chemical Co., Ltd.).

Comparative Example 3
In the preparation of the heat-sensitive recording layer coating solution of Example 1, the amount of spherical organic particles was changed to 3 parts to 5 parts, and the type was spherical organic particles (trade name: Eposta MA1013, average particle diameter 13 μm, polymethyl methacrylate). A heat-sensitive recording linerless label was obtained in the same manner as in Example 1 except that it was changed to a system cross-linked product, manufactured by Nippon Shokubai Chemical Co., Ltd.

Comparative Example 4
A thermal recording linerless label was obtained in the same manner as in Example 1 except that the amount of the spherical organic particles was changed to 15 parts instead of 3 parts in the preparation of the thermal recording layer coating liquid of Example 1.

Comparative Example 5
In the preparation of the thermal recording coating liquid of Example 1, 3 parts of spherical organic particles were not used. In addition, in the preparation of the protective layer coating solution of Example 1, 5 parts of spherical organic particles (trade name: Eposta MA1006, average particle diameter 6 μm, polymethyl methacrylate-based crosslinked product, manufactured by Nippon Shokubai Chemical Industry Co., Ltd.) were further added. A heat-sensitive recording linerless label was obtained in the same manner as in Comparative Example 1 except that it was added.

  The thermal recording linerless label thus obtained was allowed to stand for 24 hours under conditions of 40 ° C. and 50% RH, and then the following evaluation was performed. The results were as shown in Table 1.

(Print damage)
Using a thermal recording evaluation machine (trade name: TH-PMD, manufactured by Okura Electric Co., Ltd.), with a applied energy of 0.24 mJ / dot, black solid printing of 5 m in length was performed at both a printing rate of 100% and 50%, The surface after recording was visually observed, and white streak-like print shading and scratches generated on the print surface were evaluated according to the following criteria.
A: There is no printing blur and the printing surface is good.
B: There is no print shading, and there are slight scratches on the printing surface with a printing rate of 100%, but the printing surface with 50% is good.
C: There is a slight print scraping, and the print surface is scratched at both a print rate of 100% and 50%.
D: Print defects and scratches are remarkably generated on the entire surface, resulting in a print failure.

(Blocking resistance)
The resulting thermal recording linerless label was wound for 24 hours under conditions of 40 ° C. and 90% RH, and then the front and back blocking was evaluated according to the following criteria.
A: There is no blocking.
B: A little sound is heard when the take-up is extended.
C: The sound when winding is extended is loud.

Claims (7)

  A support, a thermal recording layer containing a dye precursor, a developer and a water-based adhesive, a protective layer containing a water-based adhesive, and a release layer on one side of the support from the side close to the support A thermosensitive recording linerless label having an adhesive layer on the other surface, wherein the thermosensitive recording layer contains spherical organic particles having an average particle size of 2.0 to 13 μm. label.   The heat-sensitive recording linerless label according to claim 1, wherein the heat-sensitive recording layer has an average thickness of 2 to 6 µm, and the protective layer has an average thickness of 1 to 4 µm.   The aqueous 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, silicon-modified polyvinyl alcohol, and methacrylonitrile copolymers. The thermal recording linerless label according to claim 1 or 2.   The methacrylonitrile-based copolymer is a copolymer comprising a monomer containing (i) methacrylonitrile and (ii) a vinyl monomer copolymerizable with methacrylonitrile, wherein the vinyl monomer (ii ) Includes at least one carboxyl group-containing vinyl monomer, and the content of the carboxyl group-containing vinyl monomer is 1 to 10% by mass in the monomer. Thermal recording linerless label.   The heat-sensitive recording linerless according to any one of claims 1 to 4, wherein the heat-sensitive recording layer contains one selected from the group consisting of fully saponified polyvinyl alcohol, partially saponified polyvinyl alcohol, and butadiene copolymer latex. label.   The thermal recording linerless label according to any one of claims 1 to 5, wherein an average thickness of the thermal recording layer is smaller than or equal to an average particle diameter of the spherical organic particles.   A support, a thermal recording layer containing a dye precursor and a developer, a protective layer containing an aqueous adhesive, and a release layer are provided on one side of the support from the side close to the support, and the other side is provided A method for producing a thermosensitive recording linerless label in which an adhesive layer is provided, comprising the step of forming a thermosensitive recording layer using a thermosensitive recording layer coating liquid containing spherical organic particles having an average particle size of 2.0 to 13 μm. A method for producing a thermal recording linerless label, comprising: