JP2014040075A - Thermosensitive paper, and label using the thermosensitive paper - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide thermosensitive paper that has high glossiness, and can prevent problems in printing with a thermal head of a partial glaze type (for example, printing contraction).SOLUTION: The thermosensitive paper includes a base material layer 10, a thermosensitive coloring layer 20, and a top coat layer 30 including silicone acrylic resin in this order.

Description

  The present invention relates to a thermal paper and a label using the thermal paper.

  Thermal paper is used for various purposes such as train tickets, cash register paper, thermal fax paper, meter reading paper such as electricity and gas, and labels that display prices at convenience stores and supermarkets. In recent years, the demand for glossy thermal paper is increasing, and development is underway (for example, Patent Document 1 and Patent Document 2).

  The thermal paper is usually printed by a printer having a thermal head that heats and colors the thermal paper. In recent years, a partial glaze type thermal head has been developed as the thermal head. The partial glaze type thermal head is capable of printing with higher definition than the conventional thermal head, and is expected to expand the range of use in the future. The partial glaze type thermal head can apply a larger pressure to a medium such as thermal paper than a conventional thermal head (for example, a flat glaze type thermal head) during printing, thereby realizing high-definition printing. doing. However, when thermal paper is printed with a partial glaze type thermal head, there is a problem that the thermal paper sticks to the thermal head and print shrinkage occurs. Print shrinkage is more likely to occur with glossy thermal paper having a highly smooth surface.

JP 2004-58440 A JP 2004-308034 A

  The present invention has been made in order to solve the above-described conventional problems. The object of the present invention is to have a high glossiness and a problem in printing with a partial glaze type thermal head (for example, An object of the present invention is to provide a thermal paper that can prevent printing shrinkage.

［式（１）中、Ｒ^１、Ｒ^２、および、Ｒ^３は、それぞれ同一であっても異なっていてもよく、炭素数１〜２０の炭化水素基、または、炭素原子に結合した水素原子の少なくとも一つをハロゲン原子で置換した炭素数１〜２０のハロゲン化炭化水素基を表し；Ｙはラジカル反応性基、または、−ＳＨ基、もしくはその両方を有する有機基を表し；Ｚ^１およびＺ^２はそれぞれ同一であっても異なっていてもよく、水素原子、炭素数１〜４のアルキル基、または、

（式（２）中、Ｒ^４およびＲ^５はそれぞれ同一であっても異なっていてもよく、炭素数１〜２０の炭化水素基、または、炭素数１〜２０のハロゲン化炭化水素基を表し；Ｒ^６は炭素数１〜２０の炭化水素基、または、炭素数１〜２０のハロゲン化炭化水素基、もしくは、ラジカル反応性基または−ＳＨ基もしくはその両方を有する有機基を表す）で表されるトリオルガノシリル基を表し；ｍは１０，０００以下の正の整数を表し；ｎは１以上の整数を表し；１分子中で、Ｒ^１〜Ｒ^６、Ｙはそれぞれ同一であっても異なっていてもよい］。
好ましい実施形態においては、本発明の感熱紙は、上記基材層と上記感熱発色層との間にアンダーコート層をさらに備える。
好ましい実施形態においては、本発明の感熱紙は、上記感熱発色層と上記トップコート層との間に保護層をさらに備える。
好ましい実施形態においては、本発明の感熱紙は部分グレーズタイプのサーマルヘッドを有するプリンターによる印字に使用される。
本発明の別の局面においては、ラベルが提供される。このラベルは上記感熱紙を含む。 The thermal paper of the present invention includes a base material layer, a thermal coloring layer, and a topcoat layer in this order. This topcoat layer contains a silicone acrylic resin.
In preferable embodiment, the content rate of the said silicone acrylic resin is 25 weight%-100 weight% in 100 weight% of binder components contained in the said topcoat layer.
In a preferred embodiment, the silicone acrylic resin is a silicone acrylic resin obtained by copolymerizing a polyorganosiloxane represented by the following general formula (1) and a (meth) acrylic ester:

[In Formula (1), R ¹ , R ² , and R ³ may be the same or different and each represents a hydrocarbon group having 1 to 20 carbon atoms or a hydrogen atom bonded to a carbon atom. Represents a halogenated hydrocarbon group having 1 to 20 carbon atoms in which at least one of them is substituted with a halogen atom; Y represents an organic group having a radical reactive group, a —SH group, or both; Z ¹ and Z ² may be the same or different and each represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or

(In Formula (2), R ⁴ and R ⁵ may be the same or different and each represents a hydrocarbon group having 1 to 20 carbon atoms or a halogenated hydrocarbon group having 1 to 20 carbon atoms. R ⁶ represents a hydrocarbon group having 1 to 20 carbon atoms, a halogenated hydrocarbon group having 1 to 20 carbon atoms, or a radical reactive group, an —SH group, or an organic group having both). M represents a positive integer of 10,000 or less; n represents an integer of 1 or more; in one molecule, R ^{1 to} R ⁶ and Y may be the same May be different].
In a preferred embodiment, the thermal paper of the present invention further comprises an undercoat layer between the base material layer and the thermal coloring layer.
In a preferred embodiment, the thermal paper of the present invention further includes a protective layer between the thermal coloring layer and the topcoat layer.
In a preferred embodiment, the thermal paper of the present invention is used for printing by a printer having a partial glaze type thermal head.
In another aspect of the invention, a label is provided. This label includes the thermal paper.

  According to the present invention, by including a silicone acrylic resin in the top coat layer, it has high glossiness and prevents defects (for example, print shrinkage) during printing with a partial glaze type thermal head. The thermal paper to be obtained can be provided. The thermal paper of the present invention can be suitably used without causing printing shrinkage even in a printer having a partial glaze type thermal head. Therefore, the thermal paper of the present invention can be particularly suitably used for labels in which glossy thermal paper is often used.

It is a schematic sectional drawing which shows one embodiment of the thermal paper of this invention. It is a schematic sectional drawing which shows another embodiment of the thermal paper of this invention.

<A. Thermal paper>
The thermal paper of the present invention includes a base material layer, a thermal coloring layer, and a topcoat layer in this order. The top coat layer includes a silicone acrylic resin. FIG. 1 is a schematic cross-sectional view illustrating one preferred embodiment of the thermal paper of the present invention. The thermal paper 100 includes a base material layer 10, a thermal coloring layer 20, and a topcoat layer 30 in this order. In the thermal paper 100, the topcoat layer 30 is provided on the surface of the thermal coloring layer 20 (the surface facing the thermal head when printing). When the topcoat layer 30 is in contact with the thermal head, printing shrinkage can be prevented even when printing is performed with a partial glaze type thermal head. Therefore, the thermal paper of the present embodiment can be suitably used not only for printing with a conventional flat glaze type thermal head but also with a partial glaze type thermal head. The top coat layer 30 can impart gloss to the thermal paper 100 by having a smooth surface. Since the silicone acrylic resin has little adverse effect on the glossiness, the topcoat layer 30 can impart the same glossiness to the conventional glossy thermal paper to the thermal paper 100. Therefore, the thermal paper 100 can maintain the same glossiness as that of the conventional glossy thermal paper, and can prevent print shrinkage.

  FIG. 2 is a schematic sectional view for explaining another embodiment of the thermal paper of the present invention. In this embodiment, the thermal paper 100 ′ includes a base material layer 10, an undercoat layer 40, a thermal coloring layer 20, a protective layer 50, and a topcoat layer 30. When the thermal paper 100 ′ further includes the undercoat layer 40, the smoothness of each layer is further improved. Therefore, the adhesion between the thermal paper and the thermal head is further improved, and clearer printing is possible. Further, since the thermal paper 100 ′ includes the protective layer 50, the thermal coloring layer 20 can be protected from water, plasticizer, chemicals, and the like. One of the undercoat layer 40 and the protective layer 50 may be omitted depending on the purpose, the configuration of each layer, and desired characteristics. The thermal paper of the present invention may include any appropriate other layer in addition to the above layers. For example, another protective layer or a heat insulating layer may be provided between the base material layer and the thermosensitive coloring layer. Further, a back coat layer may be provided on the surface of the base material layer 10 where the thermosensitive coloring layer 20 and the top coat layer 30 are not provided. By providing the heat insulating layer, diffusion of heat given from the thermal head can be prevented. By providing the back coat layer, it is possible to prevent the base material layer 10 from being bent and to provide a more even thermal paper. Moreover, when using the thermal paper of this invention as a label, the anchoring force of the formed adhesive layer can improve.

<A-1. Topcoat layer>
The topcoat layer 30 is provided on the outermost layer of the thermal paper. That is, the topcoat layer 30 is a layer that is in direct contact with the thermal head when the thermal paper of the present invention is printed. The top coat layer 30 includes a silicone acrylic resin. The silicone acrylic resin is used as a binder. The partial glaze type thermal head applies more pressure to the thermal paper than the conventional flat glaze type thermal head. Therefore, while higher-definition printing is possible, there is a problem that print shrinkage occurs. The topcoat layer of the thermal paper according to the present invention contains a silicone acrylic resin, and thus can prevent printing shrinkage even when printing is performed using a partial glaze type thermal head. The top coat layer 30 can give glossiness to the thermal paper by having a smooth surface. Since the silicone acrylic resin has little adverse effect on the glossiness, the topcoat layer can impart the same glossiness to the conventional glossy thermal paper to the thermal paper. Therefore, the thermal paper of the present invention can be suitably used for applications where glossy thermal paper is preferred. The top coat layer is preferably transparent so that the printing of the thermosensitive coloring layer can be visually recognized.

  The thickness of the topcoat layer can be set to any appropriate value. For example, the thickness of the top coat layer is 0.3 μm or more, preferably 0.3 μm to 5.0 μm. If the thickness of the topcoat layer is within the above range, sufficient glossiness can be imparted to the thermal paper of the present invention.

  The top coat layer contains any appropriate other component in addition to the silicone acrylic resin. Examples of the other components include binders (resins) other than silicone acrylic resins, lubricants, crosslinking agents, and fillers.

<A-1-1. Binder>
The top coat layer contains a binder. The binder may contain a resin other than the silicone acrylic resin. The content of the binder in the top coat layer can be set to any appropriate value.

<A-1-1-1. Silicone acrylic resin>
Any appropriate silicone acrylic resin is used as the silicone acrylic resin. As the silicone acrylic resin, a silicone acrylic resin obtained by copolymerizing a polyorganosiloxane represented by the following general formula (1) and a (meth) acrylic ester is preferably used.

［式（１）中、Ｒ^１、Ｒ^２、および、Ｒ^３は、それぞれ同一であっても異なっていてもよく、炭素数１〜２０の炭化水素基、または、炭素原子に結合した水素原子の少なくとも一つをハロゲン原子で置換した炭素数１〜２０のハロゲン化炭化水素基を表し；Ｙはラジカル反応性基、または、−ＳＨ基、もしくはその両方を有する有機基を表し；Ｚ^１およびＺ^２はそれぞれ同一であっても異なっていてもよく、水素原子、炭素数１〜４のアルキル基、または、

（式（２）中、Ｒ^４およびＲ^５はそれぞれ同一であっても異なっていてもよく、炭素数１〜２０の炭化水素基、または、炭素数１〜２０のハロゲン化炭化水素基を表し；Ｒ^６は炭素数１〜２０の炭化水素基、または、炭素数１〜２０のハロゲン化炭化水素基、もしくは、ラジカル反応性基または−ＳＨ基もしくはその両方を有する有機基を表す）で表されるトリオルガノシリル基を表し；ｍは１０，０００以下の正の整数を表し；ｎは１以上の整数を表し；１分子中で、Ｒ^１〜Ｒ^６、Ｙはそれぞれ同一でも異なっていてもよい］。

[In Formula (1), R ¹ , R ² , and R ³ may be the same or different and each represents a hydrocarbon group having 1 to 20 carbon atoms or a hydrogen atom bonded to a carbon atom. Represents a halogenated hydrocarbon group having 1 to 20 carbon atoms in which at least one of them is substituted with a halogen atom; Y represents an organic group having a radical reactive group, a —SH group, or both; Z ¹ and Z ² may be the same or different and each represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or

(In Formula (2), R ⁴ and R ⁵ may be the same or different and each represents a hydrocarbon group having 1 to 20 carbon atoms or a halogenated hydrocarbon group having 1 to 20 carbon atoms. R ⁶ represents a hydrocarbon group having 1 to 20 carbon atoms, a halogenated hydrocarbon group having 1 to 20 carbon atoms, or a radical reactive group, an —SH group, or an organic group having both). M represents a positive integer of 10,000 or less; n represents an integer of 1 or more; in one molecule, R ^{1 to} R ⁶ and Y are the same or different. May be good.]

In the above general formula (1), R ^{1 to} R ³ may be the same or different from each other, and represent at least one of a hydrocarbon group having 1 to 20 carbon atoms or a hydrogen atom bonded to a carbon atom. The C1-C20 halogenated hydrocarbon group substituted with the halogen atom is represented. Specific examples include alkyl groups such as methyl group, ethyl group, propyl group, and butyl group, and aryl groups such as phenyl group, tolyl group, xylyl group, and naphthyl group.

  In the general formula (1), Y represents a radical reactive group, an —SH group, or an organic group having both. Specific examples include a vinyl group, an allyl group, a γ-acryloxypropyl group, a γ-methacryloxypropyl group, and a γ-mercaptopropyl group.

In the general formula (1), Z ¹ and Z ² may be the same or different and are each represented by a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or the general formula (2). Represents a triorganosilyl group. Specific examples include lower alkyl groups such as methyl group, ethyl group, propyl group, and butyl group.

In the general formula (2), R ⁴ and R ⁵ may be the same or different, and each represents a hydrocarbon group having 1 to 20 carbon atoms or a halogenated hydrocarbon group having 1 to 20 carbon atoms. Represent. R ⁶ represents a hydrocarbon group having 1 to 20 carbon atoms, a halogenated hydrocarbon group having 1 to 20 carbon atoms, or an organic group having a radical reactive group, a —SH group, or both. Specific examples of the hydrocarbon group of R ^{4 to} R ⁶ include those exemplified for R ^{1 to} R ³ and Y in the general formula (1).

  In the said General formula (1), m is a positive integer below 10,000, Preferably it is an integer of 500-8000. In the said General formula (1), n is an integer greater than or equal to 1, Preferably it is an integer of 1-500.

  The polyorganosiloxane can be produced by any appropriate method. For example, it can be produced by polymerizing a linear or cyclic low molecular weight polyorganosiloxane having a functional group exemplified in the above description or alkoxysilane.

  Any appropriate (meth) acrylic acid ester can be used as the (meth) acrylic acid ester. For example, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, isobutyl (meth) acrylate, pentyl (meth) acrylate, hexyl (meth) acrylate, octyl (meth) acrylate, Alkyl (meth) acrylates such as 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, alkoxyalkyl (meth) acrylates such as methoxyethyl (meth) acrylate, butoxyethyl (meth) acrylate, cyclohexyl (Meth) acrylate, phenyl (meth) acrylate, benzyl (meth) acrylate and the like can be mentioned. The said (meth) acrylic acid ester may use only 1 type, and may be used in combination of 2 or more type.

  The blending ratio of the polyorganosiloxane represented by the general formula (1) and the (meth) acrylic acid ester when copolymerization is preferably 5/95 to 95/5 in weight ratio.

  In addition to the (meth) acrylic acid ester, another monomer copolymerizable with the (meth) acrylic acid ester may be copolymerized. Arbitrary appropriate monomers can be used as another monomer copolymerizable with the said (meth) acrylic acid ester. For example, styrene compounds such as styrene, vinyl toluene, α-methyl styrene, unsaturated nitriles such as acrylonitrile and methacrylonitrile, halogenated olefins such as vinyl chloride and vinylidene chloride, vinyl esters such as vinyl acetate and vinyl propionate, In addition to monomers having one double bond, such as unsaturated amides such as acrylamide, methacrylamide, N-methylolacrylamide, and unsaturated carboxylic acids such as acrylic acid, methacrylic acid, and maleic anhydride, ethylene glycol dimethacrylate, Examples thereof include polyunsaturated monomers such as propylene glycol dimethacrylate, 1,4-butanediol dimethacrylate, allyl methacrylate, triallyl cyanurate, triallyl isocyanurate. Only one type of the other monomers may be used, or two or more types may be used in combination.

  The content of the other copolymerizable monomer is 30% by weight or less with respect to 100% by weight of the total amount of the (meth) acrylic acid ester and the other copolymerizable monomer. It is preferable. Moreover, the blending ratio with the polyorganosiloxane represented by the general formula (1) when copolymerizing is the blending ratio of the (meth) acrylic acid ester and the total weight of the other monomers is the above. If it is in the range.

  The silicone acrylic resin can be obtained by graft copolymerizing the polyorganosiloxane represented by the general formula (1) and a (meth) acrylic acid ester. Polymerization of the polyorganosiloxane represented by the general formula (1) and the (meth) acrylic acid ester can be performed by any appropriate polymerization method. The silicone acrylic resin is preferably a resin obtained by graft copolymerization of polyorganosiloxane represented by the general formula (1) and (meth) acrylic acid ester by an emulsion polymerization method.

  The emulsion polymerization can be performed by any appropriate method. For example, a method of emulsifying and dispersing polyorganosiloxane represented by the general formula (1) and (meth) acrylic acid ester in water, polymerizing in the presence of a radical polymerization initiator, and performing graft copolymerization can be mentioned. As the emulsifier and radical polymerization initiator used in the emulsion polymerization, any appropriate emulsifier or radical polymerization initiator may be mentioned. A specific method for producing a silicone acrylic resin is disclosed in Japanese Patent Publication No. 7-5808. This disclosure is hereby incorporated by reference.

  As the silicone acrylic resin, a commercially available silicone acrylic resin may be used. For example, the product name “Charine” series manufactured by Nissin Chemical Industry Co., Ltd. may be mentioned.

  The content ratio of the silicone acrylic resin in 100% by weight of the binder component contained in the top coat layer is preferably 25% by weight to 100% by weight, and more preferably 40% by weight to 100% by weight. When the ratio of the silicone acrylic resin in the binder component contained in the topcoat layer is less than 25% by weight, printing shrinkage may not be sufficiently prevented.

<A-1-1-2. Other binders>
The binder may contain any appropriate other resin in addition to the silicone acrylic resin. Examples of other resins include water-soluble resins and / or emulsions of any appropriate resin. Specifically, acrylic resin, polyvinyl alcohol, modified polyvinyl alcohol, starch, modified starch, casein, gelatin, glue, gum arabic, polyamide, polyacrylamide, modified polyacrylamide, hydroxyethylcellulose, methylcellulose, carboxymethylcellulose, hydroxypropylcellulose , Polyvinyl acetate, polyacrylate, styrene-maleic anhydride copolymer, isobutylene-maleic anhydride copolymer, diisobutylene-maleic anhydride copolymer, vinyl acetate-maleic anhydride copolymer, methyl vinyl -Maleic anhydride copolymer, isopropylene-maleic anhydride copolymer, styrene-butadiene copolymer, polyvinyl chloride, polyvinylidene chloride, vinyl chloride-vinyl acetate copolymer, Polyurethane, polystyrene, polyvinyl pyrrolidone, acrylic acid esters, acrylonitrile, methyl vinyl ether. Among these resins, an acrylic resin emulsion is preferable. These resins may be used alone or in combination of two or more.

<A-1-2. Lubricant>
Any appropriate lubricant is used as the lubricant. By including a lubricant, good slipperiness can be imparted to the thermal paper. Examples of the lubricant include fatty acids such as oleic acid, oxidized waxes such as paraffin wax, polyolefin waxes such as polyethylene wax, metal soaps such as zinc stearate, ester waxes such as carnauba wax, silicon oil, whale oil Etc. The above lubricants may be used alone or in combination of two or more. The content of the lubricant can be set to any appropriate value.

<A-1-3. Cross-linking agent>
Any appropriate crosslinking agent is used as the crosslinking agent depending on the type of binder used. Examples of the cross-linking agent include glyoxal, polyaldehyde, dialdehyde type cross-linking agent such as amino-formaldehyde, polyamine type cross-linking agent such as polyethylene amine, polyimine type cross-linking agent such as polyethylene imine, epoxy type cross-linking agent, polyamide resin, glycerin. Examples thereof include diglycidyl-based crosslinking agents such as diglycidyl ether and zirconium salts such as zirconium ammonium carbonate. The said crosslinking agent may be used independently and may be used in combination of 2 or more type. The content of the crosslinking agent can be set to any appropriate value depending on the type and content of the binder used.

<A-1-4. Filler>
Any appropriate filler can be used as the filler. By including a filler, heat resistance can be imparted to the topcoat layer. Examples of the filler include aluminum hydroxide, aluminum oxide, aluminum silicate, heavy calcium carbonate, light calcium carbonate, titanium oxide, barium sulfate, silica gel, activated clay, talc, clay, kaolinite, diatomaceous earth, and white carbon. And inorganic fillers such as magnesium carbonate, magnesium oxide, magnesium hydroxide, and zinc oxide, and organic fillers such as polystyrene resin particles, urea-formalin resin particles, and polyolefin resin particles. The said filler may be used independently and may be used in combination of 2 or more type. The content of the filler can be set to any appropriate value.

<A-1-5. Other ingredients>
The topcoat layer may further contain any appropriate additive in addition to the binder, lubricant, crosslinking agent, and filler. Examples of the additive include a dispersant, an antifoaming agent, a water resistant agent, and an ultraviolet absorber. These additives may be used alone or in combination of two or more. The content of these additives can be set to any appropriate value according to desired characteristics and the like.

  The topcoat layer can be formed by any appropriate method. For example, an aqueous dispersion (composition for forming a topcoat layer) containing a binder, a lubricant, a cross-linking agent, a filler, and other additives as required is prepared, and the dispersion is applied. It can be formed by drying. The composition for forming a topcoat layer is, for example, 10 parts by weight to 50 parts by weight of a binder and a filler with 100 parts by weight of the composition for forming a topcoat layer (solid dry weight). 10 to 60 parts by weight, 1 to 30 parts by weight of a lubricant, and 1 to 10 parts by weight of a crosslinking agent.

  After applying the composition for forming the topcoat layer, while the composition is in a wet state, any suitable support having a smooth surface is adhered, and the composition is dried to dry the composition. The surface can be a smooth surface. As a result, the top coat layer can impart gloss to the surface of the thermal paper. The support to be in close contact with the topcoat layer may be a support having a smooth surface, and any appropriate support can be used. For example, polyethylene film, polypropylene film, polyamide (nylon) film, polyester film, polyethylene naphthalate film, polystyrene film, polyvinyl alcohol (vinylon) film, polyether ketone film, polysulfone film, polyether sulfone film, polyetherimide Film, ethylene copolymer film such as ethylene-vinyl acetate (EVA) copolymer film and ionomer film, polycarbonate film, cellophane film, polyvinyl chloride film, polyvinylidene chloride film, polymer film such as acetate film, or Examples thereof include metal foil such as aluminum foil. These supports may be used alone, or those supported on paper or a film may be used. Moreover, in order to ensure the peelability of the support body after topcoat layer formation, the said support body may be given arbitrary appropriate mold release processes.

<A-2. Base material layer>
Any appropriate base material is used as the base material layer. For example, high-quality paper, recycled paper, glossy paper, oil-resistant paper, coated paper, art paper, craft paper, glassine paper, cast coat paper, resin-impregnated paper, synthetic fiber paper, polyethylene terephthalate (PET) resin, Examples thereof include films of polyvinyl chloride resins, polyvinylidene chloride resins, polyolefin resins such as polypropylene. The base material layer may be a single layer or a laminate.

  The thickness of the base material layer is not limited and can be set to any appropriate value. For example, the thickness of the base material layer is 10 μm to 100 μm.

<A-3. Thermosensitive coloring layer>
The thermosensitive coloring layer includes a color former, a developer, and a binder. As the color former, any appropriate compound used as a heat-sensitive color former can be used. Examples include fluorinated compounds, trianylmethane compounds, triphenylmethane compounds, thiazine compounds, spiropyran compounds, lactam compounds, auramine compounds, and indinophthalide compounds. The color former may be used alone or in combination of two or more.

  As the developer, any appropriate compound that can cause the color former to develop color can be used. For example, an electron-accepting compound that develops a leuco dye can be used. Specifically, organic acids such as benzoic acid, metal salt compounds of organic acids such as zinc salicylate, phenols such as p-octylphenol, 4-4′thiobis (6-tertiarybutyl-2-methylphenol), etc. Thiophenol compounds, thiourea derivatives such as NN′-diphenylthiourea, and diphenylsulfone compounds such as 3,3′-diallyl-4,4′-dihydroxydiphenylsulfone. The developer may be used alone or in combination of two or more.

  Specific compounds that can be used as the color former and developer are disclosed in, for example, JP-A-6-180548 and JP-A-2004-3080324. These disclosures are incorporated herein by reference.

  Any appropriate resin can be used as the binder of the thermosensitive coloring layer. For example, the resin exemplified in the section of the top coat layer can be used. These resins may be used alone or in combination of two or more.

  The thermosensitive coloring layer may further contain any appropriate additive other than the color former, the developer, and the binder. Examples of the additive include pigments, fillers, sensitizers, stabilizers, lubricants, antifoaming agents, ultraviolet absorbers, surfactants and the like exemplified in the above section of the top coat layer.

  The thermosensitive coloring layer can be formed by any appropriate method. For example, the thermosensitive coloring layer is prepared by preparing an aqueous dispersion (composition for forming a thermosensitive coloring layer) containing a color former, a developer, a binder, and, if necessary, other additives, and applying the dispersion. Can be formed by drying.

  When a thermosensitive coloring layer is formed by applying the dispersion to the substrate layer, the substrate layer preferably has an undercoat layer on the surface on which the thermosensitive coloring layer is formed. By providing the undercoat layer on the surface of the base material layer on which the thermosensitive coloring layer is formed, the unevenness on the surface of the base material layer can be smoothed. Thereby, the adhesiveness of the obtained thermal paper with the thermal head is further improved, and the color development of the thermal coloring layer can be further improved.

  Moreover, after forming a thermosensitive coloring layer on the support body different from the said base material layer, you may laminate | stack on a base material layer through arbitrary appropriate adhesive layers. Any appropriate pressure-sensitive adhesive can be used as the pressure-sensitive adhesive. For example, SBR adhesives mainly composed of styrene-butadiene copolymer, recycled rubber adhesives mainly composed of natural rubber, SBR rubber, butyl rubber, etc., polyisobutylene adhesives mainly composed of polyisobutylene resin Agent, block rubber adhesive mainly composed of styrene-isoprene-styrene, styrene-butadiene-styrene block polymer, and acrylic acid ester copolymerized with monomers such as acrylic acid, methacrylic acid, acrylamide, vinyl acetate, styrene An acrylic pressure-sensitive adhesive mainly composed of These pressure-sensitive adhesives may be used alone or in combination of two or more.

<A-4. Other layers>
The thermal paper of the present invention may include any appropriate other layer other than the topcoat layer, the thermal coloring layer, and the base material layer. Examples of the other layers include the undercoat layer, the protective layer, the heat insulating layer, and the backcoat layer. Only one of these layers may be provided, or a plurality of layers may be provided in combination.

<A-4-1. Undercoat layer>
The undercoat layer includes, for example, a binder and a filler. Any appropriate resin component can be used as the binder. For example, the emulsion of arbitrary appropriate resin and water-soluble resin are mentioned. Examples of the emulsion include acrylic-styrene copolymer, styrene-butadiene copolymer, acrylic-butadiene-styrene copolymer, vinyl acetate resin, vinyl acetate-acrylic acid copolymer, styrene-acrylic acid ester copolymer. Examples include coalesced emulsions, acrylic ester resins, polyurethane resins and the like. Examples of the water-soluble resin include polyvinyl alcohol, starch and derivatives thereof, cellulose derivatives such as methoxycellulose, hydroxyethylcellulose, carboxymethylcellulose, methylcellulose, and ethylcellulose, polyacrylic acid soda, polyvinylpyrrolidone, and acrylamide-acrylic acid ester copolymers. , Acrylamide-acrylic acid ester-methacrylic acid terpolymer, styrene-maleic anhydride copolymer alkali salt, isobutylene-maleic anhydride copolymer alkali salt, polyacrylamide, sodium alginate, gelatin, casein, etc. . The binder may be used alone or in combination of two or more.

  Any appropriate filler can be used as the filler. Examples of the filler include inorganic fillers, organic fillers, and hollow particles. Specifically, inorganic fillers such as alumina, magnesium hydroxide, calcium hydroxide, magnesium carbonate, zinc oxide, barium sulfate, silica, calcium carbonate, kaolin, calcined kaolin, diatomaceous earth, talc, titanium oxide, aluminum hydroxide, etc. An organic filler such as urea-formalin resin, styrene-methacrylic acid copolymer, polystyrene resin, amino resin filler; Any appropriate hollow particles can be used as the hollow particles. Examples thereof include hollow particles made of a thermoplastic resin such as polystyrene, polyvinyl chloride, polyvinylidene chloride, polyvinyl acetate, polyacrylic acid ester, polyacrylonitrile, polybutadiene, and copolymers thereof. The hollow ratio of the hollow particles is, for example, 35% to 95%. These fillers may be used alone or in combination of two or more.

  The thickness of the undercoat layer can be set to any appropriate thickness. The thickness of the undercoat layer is, for example, 2 μm to 35 μm.

  The undercoat layer can be formed by any appropriate method. For example, the undercoat layer is prepared by preparing an aqueous dispersion (composition for forming an undercoat layer) containing a binder, a filler, and, if necessary, other additives, and applying and drying the dispersion. Can be formed.

<A-4-2. Protective layer>
The protective layer includes, for example, a binder. As a binder, the binder illustrated by the term of the said topcoat layer is mentioned. The protective layer may contain any appropriate additive other than the binder. Examples of the additive include a filler, a lubricant, a crosslinking agent, a dispersant, an antifoaming agent, and a water resistance-imparting agent. Examples of the filler, lubricant, and crosslinking agent include those exemplified in the section of the top coat layer. The protective layer is preferably transparent in order to ensure the printing visibility of the thermosensitive coloring layer. The thickness of the protective layer can be set to any appropriate value. The thickness of the protective layer is, for example, 0.3 μm to 3.0 μm. Moreover, you may provide another protective layer in the surface in which the said protective layer of the thermosensitive coloring layer is not provided.

  The protective layer can be formed by any appropriate method. For example, the protective layer can be formed by preparing an aqueous dispersion (composition for forming a protective layer) containing the binder and, if necessary, any appropriate additive, and applying and drying the dispersion.

<A-4-3. Thermal insulation layer>
The said heat insulation layer contains a binder and a filler, for example. Examples of the binder and filler include those exemplified in the section of the top coat layer. Moreover, the heat insulation layer may contain arbitrary appropriate other additives other than the binder and the filler. Examples of the other additive include a crosslinking agent, a dispersing agent, an antifoaming agent, a water resistant agent, and an ultraviolet absorber. The thickness of the heat insulation layer can be set to any appropriate value. The thickness of the heat insulation layer is, for example, 1.0 μm to 20 μm.

  The heat insulating layer can be formed by any appropriate method. For example, it can be formed by preparing an aqueous dispersion (composition for forming a heat insulating layer) containing a binder, a filler, and other additives as necessary, and applying and drying the dispersion.

<A-4-4. Backcoat layer>
The back coat layer includes, for example, a binder and a filler. Examples of the binder and filler include those exemplified in the section of the top coat layer. Moreover, since the back coat layer can provide a thermal paper having more excellent smoothness, polyvinyl alcohol resins such as vinylidene chloride resin and silicon-modified polyvinyl alcohol resin, starch, SBR latex, acrylic resin, You may form using resin, such as a urethane type resin. The backcoat layer may contain any appropriate other additive. Examples of the other additive include a crosslinking agent, a dispersing agent, an antifoaming agent, a water resistant agent, and an ultraviolet absorber. The thickness of the back coat layer can be set to any appropriate value. The thickness of the back coat layer is, for example, 0.3 μm to 5.0 μm.

  The back coat layer can be formed by any appropriate method. For example, it can be formed by preparing an aqueous dispersion (composition for forming a heat insulating layer) containing a binder or the above resin, additives, and other additives as necessary, and applying and drying the dispersion. .

<A-5. Manufacturing method of thermal paper>
The thermal paper of the present invention can be produced by any suitable method. For example, it can be obtained by the following method. First, a composition for forming a layer other than the topcoat layer on the base material layer is sequentially applied and dried to obtain a laminate. Next, a composition for forming a topcoat layer is applied to the surface (for example, a heat-sensitive color developing layer) on which each layer of the laminate is formed, and while the composition for forming the topcoat layer is in a wet state, smoothness is applied. Any suitable support having a smooth surface is brought into close contact, and the topcoat layer is dried (cured). Subsequently, the thermal paper of this invention is obtained by peeling the support body closely_contact | adhered to the topcoat layer.

  The application | coating process of the composition which forms each said layer can be performed by arbitrary appropriate methods. For example, it can be performed by applying a composition for forming each layer using a bar coater, a blade coater or the like.

  Moreover, the following method is mentioned as another method of manufacturing a thermal paper. For example, a composition for forming a heat-sensitive color forming layer and any other layer after applying a composition for forming a topcoat layer on any appropriate support having a smooth surface and drying the composition to form a topcoat layer The thermal paper of the present invention is obtained by applying a product or material and drying to form a laminate. After laminating the obtained laminate and the base material layer via any appropriate pressure-sensitive adhesive layer, the thermal paper of the present invention is obtained by peeling the support.

  Specific methods for producing thermal paper include, for example, the methods described in JP-A Nos. 2004-58440 and 2004-308034. Moreover, the thermal paper of this invention may be obtained by apply | coating the composition which forms the said topcoat layer to the outermost layer (surface which contacts a thermal head) of commercially available thermal paper, and drying.

  The thermal paper of the present invention can prevent printing shrinkage even when printing is performed using a partial glaze type thermal head. Therefore, it can be suitably used for applications that require finer printing. Further, the thermal paper of the present invention has the same level of gloss as conventional glossy thermal paper. Therefore, it can be suitably used for applications where glossy thermal paper is preferably used. For example, as described later, it can be suitably used as a label, a ticket, a slip, or the like.

<B. Label>
The label of this invention contains the said thermal paper. Since the thermal paper used for the label of the present invention has the top coat layer, printing shrinkage can be prevented even when printing is performed using a partial glaze type thermal head. Furthermore, by making the topcoat layer a smooth surface, it has a glossiness comparable to that of conventional glossy thermal paper. Therefore, it can be particularly suitably used for food display labels or price tag labels such as supermarkets and convenience stores where glossy thermal paper is preferred. In these applications, printing of finer information is required, particularly with a partial glaze type thermal head, and the label of the present invention can satisfy these demands.

  The label of the present invention includes an adhesive layer in one embodiment. The pressure-sensitive adhesive layer includes any appropriate pressure-sensitive adhesive. Examples of the pressure-sensitive adhesive include acrylic pressure-sensitive adhesives, natural rubber-based pressure-sensitive adhesives, and synthetic rubber-based pressure-sensitive adhesives. The thickness of the pressure-sensitive adhesive layer can be set to any appropriate value. The thickness of the pressure-sensitive adhesive layer is usually 7 μm to 60 μm, preferably 10 μm to 35 μm. Moreover, since the label of this embodiment protects an adhesive layer until use, a separator is usually bonded together. Any appropriate separator can be used as the separator.

  The label of this embodiment can be manufactured by any appropriate method. For example, any appropriate pressure-sensitive adhesive is applied to the surface of the thermal paper base material layer that is not provided with a layer such as a heat-sensitive color forming layer to form a pressure-sensitive adhesive layer. It can be manufactured by laminating a separator.

  As described above, the label of the present invention can prevent the occurrence of print shrinkage even when printing is performed using a partial glaze type thermal head. Therefore, it can be suitably used for applications that require finer printing. Furthermore, the label of the present invention has the same level of gloss as conventional glossy thermal paper. Therefore, it can be particularly suitably applied to various uses in which glossy thermal paper is preferably used. For example, the label of the present invention can be suitably used for food display labels at convenience stores and supermarkets, price tag labels, and the like.

  EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited by these Examples. In Examples and Comparative Examples, “part” and “%” are based on weight unless otherwise specified.

[Example 1]
High quality paper was used as the base material layer. A thermal recording layer forming composition was applied and dried on one surface of the fine paper to form a thermal recording layer. Subsequently, each material was uniformly disperse | distributed with the compounding ratio (solid content weight reference | standard) shown in Table 1, and the composition for topcoat layer formation was prepared. The topcoat layer-forming composition was applied onto the heat-sensitive recording layer, and the applied topcoat layer-forming composition and the film were bonded together before the applied topcoat layer-forming composition was cured. After the composition for forming the topcoat layer was dried and the topcoat layer was formed, the film was peeled off to obtain a thermal paper.

[Examples 2 to 6]
Thermal paper was obtained in the same manner as in Example 1 except that the composition of the composition for forming the topcoat layer was changed to the ratio shown in Table 1.

(Comparative Examples 1 and 2)
Thermal paper was obtained in the same manner as in Example 1 except that the composition of the composition for forming the topcoat layer was changed to the ratio shown in Table 1.

[Evaluation]
The following evaluation was performed about each thermal paper obtained by the Example and the comparative example. The results are shown in Table 2.

(1) Glossiness About the surface of the obtained thermal paper on the topcoat layer side, the glossiness is measured according to JIS Z 8741 using a gloss meter (trade name: PG-1M, manufactured by Nippon Denshoku Kogyo Co., Ltd.). (Measurement reflection angle: 60 °, 20 °) was measured. If the glossiness at 60 ° is 40 or more and the glossiness at 20 ° is 10 or more, it can be suitably used for applications in which glossy thermal paper is used.
(2) Printing shrinkage Printing was performed using a printer (product name: Respre R412v, manufactured by Sato Co., Ltd.) having a partial glaze type thermal head on the obtained thermal paper (printing speed: 50 mm / sec, printing density: 5). Visually check the printed thermal paper, ◎ if there is no print shrinkage at all, ○ if there is a slight print shrinkage but there is no problem in print visibility, print shrinkage occurs, printing The case where it was difficult to visually recognize the surface was rated as x.

  As is clear from Table 2, the thermal papers of Examples 1 to 6 having a topcoat layer containing a silicone acrylic resin as a binder are printed even when printed using a printer having a partial glaze type thermal head. Shrinkage was prevented and the visibility of the printed surface was ensured. In particular, print shrinkage did not occur at all in the thermal papers of Examples 2 to 6. Further, the thermal papers of Examples 1 to 6 had high glossiness, and were sufficiently applicable as glossy thermal paper.

  On the other hand, the thermal papers of Comparative Examples 1 and 2 having a topcoat layer that does not contain a silicone acrylic resin, although having high gloss, cause print shrinkage and are suitable for printing by a printer having a partial glaze type thermal head. There wasn't.

  The thermal paper of the present invention can be suitably used for applications requiring high-definition printing and high gloss. Moreover, the label using the thermal paper of the present invention can be used particularly suitably as a label for food display or a label for price display in a supermarket or a convenience store.

DESCRIPTION OF SYMBOLS 10 Base material 20 Thermal coloring layer 30 Topcoat layer 40 Undercoat layer 50 Protective layer 100, 100 'Thermal paper

Claims (7)

A thermal paper comprising a base material layer, a thermal coloring layer, and a topcoat layer in this order,
A thermal paper in which the topcoat layer contains a silicone acrylic resin.   The thermal paper according to claim 1, wherein a content ratio of the silicone acrylic resin is 25% by weight to 100% by weight in 100% by weight of the binder component contained in the top coat layer. The thermosensitive resin according to claim 1 or 2, wherein the silicone acrylic resin is a silicone acrylic resin obtained by copolymerizing a polyorganosiloxane represented by the following general formula (1) and a (meth) acrylic ester. paper:

[In Formula (1), R ¹ , R ² , and R ³ may be the same or different and each represents a hydrocarbon group having 1 to 20 carbon atoms or a hydrogen atom bonded to a carbon atom. Represents a halogenated hydrocarbon group having 1 to 20 carbon atoms in which at least one of them is substituted with a halogen atom; Y represents a radical-reactive group and / or an —SH group, or an organic group having both; Z ¹ and Z ² may be the same or different and each represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or

(In Formula (2), R ⁴ and R ⁵ may be the same or different and each represents a hydrocarbon group having 1 to 20 carbon atoms or a halogenated hydrocarbon group having 1 to 20 carbon atoms. R ⁶ represents a hydrocarbon group having 1 to 20 carbon atoms, a halogenated hydrocarbon group having 1 to 20 carbon atoms, or a radical reactive group, an —SH group, or an organic group having both). M represents a positive integer of 10,000 or less; n represents an integer of 1 or more; even if R ^{1 to} R ⁶ and Y are the same in one molecule, May be different].   The thermal paper according to any one of claims 1 to 3, further comprising an undercoat layer between the base material layer and the thermosensitive coloring layer.   The thermal paper according to any one of claims 1 to 4, further comprising a protective layer between the thermosensitive coloring layer and the topcoat layer.   The thermal paper according to any one of claims 1 to 5, which is used for printing by a printer having a partial glaze type thermal head.   A label comprising the thermal paper according to claim 1.

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