JP2021045949A - Thermosensitive recording body - Google Patents

Abstract

To provide a thermosensitive recording body that has transparency and water resistance, and in particular materializes excellent print visibility.SOLUTION: There is provided a thermosensitive recording body comprising on one surface of a transparent film base material, at least: a transparent thermosensitive layer composed of at least a leuco dye, a developer and a binder component; and a transparent protective layer composed of at least a binder component, a lubricant and calcium carbonate on the outermost layer of the surface in which the thermosensitive layer is provided, wherein the 60-degree specular gloss (JIS Z8741) on the protective layer side of the thermosensitive recording body is 40 or less, the haze (JIS K7136) of the thermosensitive recording body is 85% or less, and the total light transmittance (JIS K7361-1) of the thermosensitive recording body is 70% or more.SELECTED DRAWING: Figure 1

Description

In the present invention, a heat-sensitive layer having transparency that develops color by receiving heat energy from a thermal head of a thermal printer on one surface of a transparent film base material, and a heat-sensitive layer on the outermost layer of the surface further provided with the heat-sensitive layer. The present invention relates to a thermal recording body provided with at least a protective layer having transparency for protecting the surface.

A heat-sensitive recorder in which a heat-sensitive layer mainly composed of leuco dye, a developer, and a binder component is coated on a paper base material is easy to handle, generates less waste, has excellent cost performance, and has a simple printer structure. Moreover, it is already widely used in applications such as receipt paper, fax paper, various tickets, product display labels, and distribution management labels because it is easy to miniaturize. However, in a heat-sensitive recorder in which a heat-sensitive layer is simply provided on such a paper base material, printing becomes thin when it gets wet with water, the paper base material is deformed, and the heat-sensitive layer itself is a paper base. It is known that problems such as peeling from the material occur, and it has been avoided to use it outdoors or in an environment where it is easily wet with water.

In order to solve such problems, various efforts have been made so far, using water-resistant synthetic paper or film as the base material, and the upper layer of the heat-sensitive layer so that the heat-sensitive layer does not come into direct contact with water. Improvements have been made such as providing a protective layer and a protective film on the surface (Patent Document 1). Among the heat-sensitive recording materials with such improved water resistance, a heat-sensitive layer having transparency on one surface on a transparent film substrate and protection having water resistance and transparency on the upper layer. The heat-sensitive recorder, which is provided by stacking layers, is attached to the surface of temporary outdoor notices such as wood grain signs, white signs, and lighting signs that make use of the background design and lighting by utilizing the fact that it is transparent. It is possible to display the contents, production date and expiration date while preventing the packaged food from being invisible, as well as for use as a welcome sign for inns, information signs for condolences, and menu displays for stores. It is used for food packaging printing media, for example, a transparent packaging film itself for foods having a transparent heat-sensitive layer, and a transparent label having a transparent heat-sensitive layer to be attached to a transparent packaging for foods.

However, a heat-sensitive recording material in which a transparent heat-sensitive layer and a transparent protective layer or protective film are provided on a transparent film substrate as described above can be used as a protective layer or protective film for the heat-sensitive recording material. Due to the extremely strong gloss on the side where it is provided, not only is the appearance of the bulletin board significantly different from that of an outdoor bulletin board written directly on paper or wood using ink, but also the print is visible. There is a problem that the visibility of printing becomes very poor depending on the angle and the angle of the light that hits the printing.

JP-A-2009-255469

The present invention has been made in view of such a situation, and it is the present invention to provide a heat-sensitive recording body having transparency and water resistance, particularly excellent in print visibility. This is the main issue.

Means to solve problems

As a result of studies by the present inventor in order to solve these problems, a heat-sensitive layer having at least a transparency composed of a leuco dye, a color developer and a binder component is provided on one surface of the transparent film base material. It is composed of at least a binder component, a lubricant, and various matting agents for suppressing the gloss on the protective layer side of the thermal recording body in order to protect the thermal layer and impart water resistance to the outermost layer of the surface on which the thermal layer is provided. As a result of examining the various matting agents by providing a transparent protective layer, the gloss of the protective layer side of the thermal recording body is effectively suppressed by using calcium carbonate as the protective layer. It has been found that it is possible not to deteriorate the basic performance of the thermal recorder such as the print quality, the effect of suppressing the sticking phenomenon, and the effect of cleaning the thermal head.

Furthermore, as a result of the inventor examining the transparency of the thermal recording body, the visibility of printing, and the matte feeling of the surface on the protective layer side while examining the composition of various raw materials constituting the thermal layer and the protective layer, the thermal recording body The 60-degree mirror surface gloss (JIS Z8741) on the protective layer side is adjusted to 40 or less, the haze of the thermal recording body (JIS K7136) is adjusted to 85% or less, and the total light transmittance of the thermal recording body (JIS K7361-1). ) To 70% or more, it is possible to suppress the gloss on the protective layer side of the thermal recording body while maintaining the appropriate transparency of the thermal recording body, so the visibility of printing is excellent. We have found that it is possible to provide a thermal recorder.

Effect of the invention

If the heat-sensitive recorder of the present invention is used, it can be used outdoors or in contact with water because it has water resistance, and it can transmit light or transmit light because it has appropriate transparency. It is also possible to use the design on the back side and visually recognize the object on the back side of the thermal recording body, and it is also possible to produce a printed matter with a matte texture and excellent print visibility. Is.

The schematic cross-sectional view which shows an example of embodiment of the thermal recording body of this invention. The schematic cross-sectional view which shows an example of embodiment of the thermal recording body of this invention.

Basically, as shown in FIG. 1, the heat-sensitive recording body 4 in the present invention is provided with a transparent heat-sensitive layer 2 on one surface of the transparent film base material 1, and further provided with the heat-sensitive layer 2. It features a structure in which at least a transparent protective layer 3 is provided on the outermost layer. It should be noted that, as long as the problem of the present invention is not hindered, printability, coatability, and various chemical resistances between the transparent film base material 1 and the heat-sensitive layer 2 and between the heat-sensitive layer 2 and the protective layer 3 Various functionalizing layers (under layer, cushion layer, primer layer, barrier layer, intermediate layer, etc.) for improving weather resistance, adhesion, etc. may be separately provided. Further, in order to easily attach the heat-sensitive recording body 4 of the present invention to a signboard, a food packaging material, or the like, as shown in FIG. 2, the transparent film base material 1 is transparent on the surface opposite to the surface provided with the heat-sensitive layer 2. An adhesive layer 5 having a property may be provided in advance and used as a label. Further, the heat-sensitive recording body 4 without the adhesive layer 5 as shown in FIG. 1 has transparency at a position corresponding to the adhesive layer 5 in FIG. 2 after printing is performed on the heat-sensitive recording body 4. The adhesive may be provided by post-processing and then attached to a signboard or the like for use.

<< Regarding thermal recorder >>
The heat-sensitive recording material in the present invention has a structure in which a transparent heat-sensitive layer is provided on one surface of a transparent film base material, and at least a transparent protective layer is provided on the outermost layer of the surface provided with the heat-sensitive layer. It is characterized by.

The thickness of the heat-sensitive recorder of the present invention is not particularly limited, but is preferably in the range of 20 to 300 μm, more preferably 30 to 120 μm. When the thickness of the thermal recording body is within the above range, problems such as printing defects and transport defects in the printer are unlikely to occur during printing, and it is easy to handle.

The 60-degree mirror surface gloss (JIS Z8741) on the protective layer side of the heat-sensitive recording body of the present invention is preferably 40 or less, and more preferably 30 or less. The lower the 60-degree mirror glossiness, the better the visibility of printing. Therefore, the lower limit is not particularly limited. However, if the 60-degree mirror glossiness is 1 or more, there is no problem in solving the problem of the present invention. .. As a result of examining the visibility of printing, the present inventor basically, the lower the 60-degree mirror glossiness on the protective layer side of the thermal recording body, the more the visibility depends on the viewing angle of the printing and the angle of the light hitting the printing. It has been found that the visibility of printing becomes almost good when the phenomenon of deterioration is suppressed and the glossiness of the mirror surface at least 60 degrees is 40 or less. Unless otherwise specified, the 60-degree mirror gloss on the protective layer side of the thermal recording body of the present invention is the 60-degree mirror gloss on the protective layer side of the thermal recording body in the unprinted portion.

The haze (JIS K7136) of the heat-sensitive recorder of the present invention is preferably 85% or less, and more preferably 80% or less. When the haze is higher than 85%, the transparency of the thermal recording body of the present invention is extremely reduced, and the visibility of objects and designs on the back surface of the thermal recording body is significantly reduced. For example, when a printed matter using a thermal recording body with a haze of more than 85% is attached to a wood grain signboard, the wood grain design that should be utilized originally looks blurry and cannot be clearly recognized. On the contrary, the lower the haze, the better the visibility of the object and the design on the back surface of the heat-sensitive recording body. Therefore, the lower limit is not particularly limited. However, in the heat-sensitive recording body of the present invention, the haze is 60 degrees as described above. There is almost an inverse correlation with the mirror gloss, and if you try to suppress the 60 degree mirror gloss on the protective layer side of the thermal recording body to 40 or less, the haze will be at least 60% or more, so use that as the lower limit of the haze. May be good. Unless otherwise specified, the haze of the heat-sensitive recording body of the present invention is the haze of the heat-sensitive recording body of the unprinted portion.

The total light transmittance (JIS K7361-1) of the heat-sensitive recorder of the present invention is preferably at least 70% or more, and more preferably 80% or more. If the total light transmittance is 70% or more, at least the transparency of the thermal recording body itself is guaranteed at a minimum, the light from the back surface of the thermal recording body is sufficiently transmitted, and the object on the back surface of the thermal recording body The visibility of the design is improved. The higher the total light transmittance, the more the performance of the heat-sensitive recorder tends to improve. Therefore, there is no particular upper limit to the total light transmittance and 100% is not a problem, but in reality, the transparent film substrate itself Since the upper limit of the total light transmittance rarely exceeds 95%, it may be used as the upper limit. Unless otherwise specified, the total light transmittance of the heat-sensitive recording body of the present invention is the total light transmittance of the heat-sensitive recording body of the unprinted portion.

The reflection concentration (ISO 5-4) on the protective layer side of the heat-sensitive recording body of the present invention is not particularly limited, but is preferably in the range of 0.01 to 0.20, and is preferably in the range of 0.01 to 0.15. Is more preferable. The reflection density in the present invention was measured using a spectrophotometric / densitometer "X-Rite eXact" manufactured by X-Rite. If the reflection density on the protective layer side of the thermal recording body exceeds the upper limit of the above range, a problem occurs in which the object or design on the back side of the thermal recording body looks light and bluish. This is a so-called "fog" phenomenon in which the leuco dye in the heat-sensitive layer and the color developer react with each other due to heat in the manufacturing process, for example, in the drying process to develop color. It is not desirable to end up. Further, the heat-sensitive recording material used in the present invention needs to have a certain degree of heat resistance for use in outdoor posting applications, etc., and even if the heat-sensitive recording material is allowed to stand in a dryer set at 40 ° C. for 24 hours, the heat-sensitive recording material is It is preferable that the reflection density on the protective layer side is within the above-mentioned range. Unless otherwise specified, the reflection density on the protective layer side of the thermal recording body of the present invention is the reflection density on the protective layer side of the thermal recording body in the unprinted portion.

In the heat-sensitive recorder of the present invention, the maximum value of the reflection density of the printed portion is preferably at least 1.50 or more, and more preferably 1.60 or more. When the reflection density of the printed part is less than 1.50, the color of the heat-sensitive layer is insufficient and the print looks bluish, or the color of the heat-sensitive layer is sufficient but the effect of the protective layer. In many cases, the print looks cloudy, and in such a case, the visibility of the print tends to deteriorate.

In the heat-sensitive recorder of the present invention, the 60-degree mirror glossiness of the printed portion is preferably at least 50 or less, and more preferably 40 or less. When the 60-degree mirror glossiness of the printed portion is 50 or less, the visibility of the print tends to be improved. Conversely, when the 60-degree mirror glossiness of the printed portion exceeds 50, the viewing angle of the print and the light corresponding to the print are applied. The visibility of printing tends to deteriorate depending on the angle of. The smaller the 60-degree mirror glossiness of the printed portion of the thermal recorder, the better the visibility of printing. Therefore, the lower limit is not particularly limited, but if the 60-degree mirror glossiness of the printed portion is 1 or more. There is no problem in solving the problem of the present invention. The measurement of the 60-degree mirror glossiness of the printed portion is the heat sensitivity when the reflection density of the printed portion is almost the maximum, more specifically, the reflection density of the printed portion is 95% or more of the maximum value of the reflection density of the printed portion. It is preferable to measure the printed portion of the recording body. The 60-degree mirror glossiness of the printed portion has almost a correlation with the 60-degree mirror surface glossiness of the unprinted portion of the thermal recording body on the protective layer side, and the 60-degree mirror surface of the unprinted portion of the thermal recording body on the protective layer side. If the glossiness is 40 or less, the 60-degree mirror glossiness of the printed portion tends to be about 50 or less.

<< About each component of the thermal recording body >>
Next, a detailed description of each component of the heat-sensitive recording body of the present invention is shown below.

<Transparent film base material>
The transparent film base material used for the heat-sensitive recording material of the present invention is not particularly limited, and for example, polyethylene terephthalate film, nylon film, polystyrene film, polycarbonate film, polypropylene film, ethylene-vinyl alcohol copolymer film, ethylene-methacrylic acid. Although it is possible to use a transparent film made from various known synthetic resins such as a copolymer film, it is more preferable to use a polyethylene terephthalate film, a nylon film, a polypropylene film or the like. The total light transmittance of the transparent film substrate used in the present invention is preferably at least 75%, more preferably 80% or more, and the haze of the transparent film substrate used in the present invention is 60% or less. Is preferable, and 40% or less is more preferable. Further, the transparent film base material used in the present invention may be a single-layer film or a multilayer film in which a plurality of films are laminated.

The thickness of the transparent film substrate of the present invention is not particularly limited, but is preferably in the range of 6 to 250 μm, more preferably in the range of 20 to 100 μm, and most preferably in the range of 30 to 80 μm. .. If the thickness of the transparent film base material is within the above range, there is no problem in printability and transportability with a printer, and further, it can be used without problems in terms of visibility of objects and designs on the back side of the thermal recording body. ..

<Thermal layer>
The heat-sensitive layer used in the heat-sensitive recorder of the present invention is composed of at least a leuco dye, a color developer, and a binder component, and various other raw materials may be further blended if necessary. The heat-sensitive layer of the present invention needs to have transparency, and is preferably at least light-colored and translucent, and more preferably colorless and transparent. The heat-sensitive layer has a function of developing color by reacting the leuco dye and the color developer only in the portion where heat is applied by the thermal head of the thermal printer.

The leuco dye used in the heat-sensitive layer of the heat-sensitive recording material of the present invention can be appropriately selected from those generally used for the heat-sensitive recording material according to the purpose, and specifically, triphenyl. Examples thereof include methane-based, fluorane-based, phenothiazine-based, auramine-based, spiropyran-based, and indolinophthalide-based. More specifically, for example, 2-anilino-3-methyl-6-dibutylaminofluorane, 2-anilino-3-methyl-6-dipentylaminofluorane, 2-anilino-3-methyl-6- [ethyl (4-Methylphenyl) amino] fluorane, 3,3-bis (p-dimethylaminophenyl) -phthalide, 3,3-bis (p-dimethylaminophenyl) -6-dimethylaminophthalide, 3,3-bis (P-Dimethylaminophenyl) -6-diethylaminophthalide, 3,3-bis (p-dimethylaminophenyl) -6-chlorophthalide, 3,3-bis (p-dibutylaminophenyl) phthalide, 3-cyclohexylamino- 6-Chlorofluorane, 3-dimethylamino-5,7-dimethylfluorane, 3- (N-methyl-N-isobutyl) -6-methyl-7-anilinofluorane, 3- (N-ethyl-N) -Isoamyl) -6-methyl-7-anilinofluorane, 3-diethylamino-7-chlorofluorane, 3-diethylamino-7-methylfluorane, 3-diethylamino-7,8-benzfluorane, 3-diethylamino -6-Methyl-7-chlorofluorine, 3- (N-p-tolyl-N-ethylamino) -6-methyl-7-anilinofluoran, 3-pyrrolidino-6-methyl-7-anilinoflu Olan, 2- {N- (3'-trifluolmethylphenyl) amino} -6-diethylaminofluorane, 2- {3,6-bis (diethylamino) -9- (o-chloroanilino) xanthyl benzoate lactam}, 3-Diethylamino-6-methyl-7- (m-trichloromethylanilino) fluorane, 3-diethylamino-7- (o-chloroanilino) fluorane, 3-dibutylamino-7- (o-chloroanilino) fluorane, 3-( N-methyl-N-amylamino) -6-methyl-7-anilinofluorane, 3- (N-methyl-N-cyclohexylamino) -6-methyl-7-anilinofluorane, 3-diethylamino-6- Methyl-7-anilinofluorane, 3-diethylamino-6-methyl-7- (2', 4'-dimethylanilino) fluorane, 3- (N, N-diethylamino) -5-methyl-7- (N) , N-dibenzylamino) fluorane, benzoyl leucomethylene blue, 6'-chloro-8'-methoxy-benzoindolino-spiropirane, 6'-bromo-3'-methoxy-benzoindolino-spiropirane, 3 -(2'-Hydroxy-4'-dimethylaminophenyl) -3- (2'-methoxy-5'-chlorophenyl) phthalide, 3- (2'-hydroxy-4'-dimethylaminophenyl) -3- (2) ′ -Methoxy-5′-nitrophenyl) phthalide, 3- (2′-hydroxy-4′-diethylaminophenyl) -3- (2′-methoxy-5′-methylphenyl) phthalide, 3- (2′-methoxy) -4'-Dimethylaminophenyl) -3- (2'-hydroxy-4'-chloro-5'-methylphenyl) phthalide, 3-morpholino-7- (N-propyl-trifluoromethylanilino) fluorane, 3 -Pyrrolidino-7-trifluoromethylanilinofluorane, 3-diethylamino-5-chloro-7- (N-benzyl-trifluoromethylanilino) fluorane, 3-pyrrolidino-7- (di-p-chlorophenyl) methyl Aminofluorane, 3-diethylamino-5-chloro-7- (α-phenylethylamino) fluorane, 3- (N-ethyl-p-toluizino) -7- (α-phenylethylamino) fluorane, 3-diethylamino- 7- (o-methoxycarbonylphenylamino) fluorane, 3-diethylamino-5-methyl-7- (α-phenylethylamino) fluorane, 3-diethylamino-7-piperidinofluorane, 2-chloro-3-( N-Methyltoluizino) -7- (pn-butylanilino) fluorane, 3- (N-methyl-N-isopropylamino) -6-methyl-7-anilinofluorane, 3-dibutylamino-6-methyl-7 -Anilinofluorane, 3,6-bis (dimethylamino) fluorenspiro (9,3') -6'-dimethylaminophthalide, 3- (N-benzyl-N-cyclohexylamino) -5,6-benzo -7-α-naphthylamino-4'-bromofluorane, 3-diethylamino-6-chloro-7-anilinofluorane, 3- {N-ethyl-N- (2-ethoxypropyl) amino} -6- Methyl-7-anilinofluorane, 3- {N-ethyl-N-tetrahydrofurfurylamino} -6-methyl-7-anilinofluorane, 3-diethylamino-6-methyl-7-mesitidino-4', 5'-Benzofluorane, 3- (p-dimethylaminophenyl) -3- {1,1-bis (p-dimethylaminophenyl) ethylene-2-yl} phthalide, 3- (p-dimethylaminophenyl)- 3- {1, 1-bis (p-dimethylaminophenyl) ethylene-2-yl} -6-dimethylaminophthalide, 3- (p-dimethylaminophenyl) -3- (1-p-dimethylaminophenyl-1-phenylethylene-) 2-yl) phthalide, 3- (p-dimethylaminophenyl) -3- (1-p-dimethylaminophenyl-1-p-chlorophenylethylene-2-yl) -6-dimethylaminophthalide, 3- (4) ′ -Dimethylamino-2'-methoxy) -3- (1 ″ -p-dimethylaminophenyl-1 ″ -p-chlorophenyl-1 ″, 3 ″ -butadiene-4 ″ -yl) benzophthalide, 3- (4 ′) -Dimethylamino-2'-benzyloxy) -3- (1 ″ -p-dimethylaminophenyl-1 ″ -phenyl-1 ″, 3 ″ -butadiene-4 ″ -yl) benzophthalide, 3-dimethylamino-6- Dimethylamino-fluoren-9-spiro-3'(6'-dimethylamino) phthalide, 3,3-bis {2- (p-dimethylaminophenyl) -2- (p-methoxyphenyl) ethenyl} -4,5 , 6,7-Tetrachlorophthalide, 3-bis {1,1-bis (4-pyrrolidinophenyl) ethylene-2-yl} -5,6-dichloro-4,7-dibromophthalide, bis (p) -Dimethylaminostyryl) -1-naphthalenesulfonylmethane, bis (p-dimethylaminostyryl) -1-p-tolylsulfonylmethane, and the like, but are not limited thereto. These may be used alone or in combination of two or more.

The color developer used in the heat-sensitive layer of the heat-sensitive recorder of the present invention can be appropriately selected from known electron-accepting compounds according to the purpose, and specifically, a phenolic compound and thio. Examples thereof include phenolic compounds, thiourea derivatives, organic acids or metal salts thereof. More specifically, for example, 4,4'-isopropyridenebisphenol, 3,4'-isopropyridenebisphenol, 4,4'-isopropyridenebis (o-methylphenol), 4,4'-secondary butylidenebisphenol. , 4,4'-isopropyridenebis (o-terrific butylphenol), 4,4'-cyclohexylidenediphenol, 4,4'-isopropyridenebis (2-chlorophenol), 2,2'-methylenebis (4) -Methyl-6-terrary butylphenol), 2,2'-methylenebis (4-ethyl-6-terrary butylphenol), 4,4'-butylidenebis (6-terrific butyl-2-methyl) phenol, 1,1 , 3-Tris (2-methyl-4-hydroxy-5-tershaly butylphenyl) butane, 1,1,3-Tris (2-methyl-4-hydroxy-5-cyclohexylphenyl) butane, 4,4'- Thiobis (6-territory butyl-2-methyl) phenol, 4,4'-diphenol sulfone, 4,2'-diphenol sulfone, 4-isopropoxy-4'-hydroxydiphenyl sulfone, 4-hydroxy-4' -Allyloxydiphenylsulfone, 4-benzyloxy-4'-hydroxydiphenylsulfone, 4,4'-diphenolsulfoxide, isopropyl P-hydroxybenzoate, benzyl P-hydroxybenzoate, benzyl protocatechuate, stearyl gallate, gallic acid Lauryl, octyl phenolic acid, 1,7-bis (4-hydroxyphenylthio) -3,5-dioxaheptane, 1,5-bis (4-hydroxyphenylthio) -3-oxaheptan, 1,3-bis (4-Hydroxyphenylthio) -propane, 2,2'-methylenebis (4-ethyl-6-terrary butylphenol), 1,3-bis (4-hydroxyphenylthio) -2-hydroxypropane, N, N' -Diphenylthiourea, N, N'-di (m-chlorophenyl) thiourea, salicylanilide, 5-chloro-salitylanilide, salicyl-o-chloroanilide, 2-hydroxy-3-naphthoic acid, antipyrine of zinc thiocyanolate Complex, zinc salt of 2-acetyloxy-3-naphthoic acid, 2-hydroxy-1-naphthoic acid, 1-hydroxy-2-naphthoic acid, metal salt of hydroxynaphthoic acid such as zinc, aluminum, calcium, bis- ( 4-Hydroxyphenyl ) Methyl ester acetate, benzyl bis- (4-hydroxyphenyl) acetate, 4- {β- (p-methoxyphenoxy) ethoxy} salicylic acid, 1,3-bis (4-hydroxycumyl) benzene, 1,4- Bis (4-hydroxycumyl) benzene, 2,4'-diphenol sulfone, 3,3'-diallyl-4,4'-diphenol sulfone, α, α-bis (4-hydroxyphenyl) -α-methyl Antipyrine complex of zinc toluenethiocyanate, tetrabromobisphenol A, tetrabromobisphenol S, 4,4'-thiobis (2-methylphenol), 3,4-hydroxy-4'-methyl-diphenylsulfone, 4,4'- Thiobis (2-chlorophenol), N-p-tolylsulfonyl-N'-phenylurea, N-p-toluenesulfonyl-N'-3- (p-toluenesulfonyloxy) phenylurea, diphenylsulfone derivative, urea urethane compound Examples thereof include, but are not limited to, derivatives. The above-mentioned developer may be used alone or in combination of two or more.

The binder component used for the heat-sensitive layer of the heat-sensitive recording medium of the present invention is intended to be a binder component having colorless transparent or light-colored translucent transparency from those generally used for the heat-sensitive recording body. Specifically, polyvinyl alcohol, gelatin, casein, starch or a derivative thereof, methoxycellulose, hydroxyethylcellulose, carboxymethylcellulose, methylcellulose, ethylcellulose and other cellulose-based resins, polyvinylpyrrolidone, etc. can be appropriately selected and used. Soda alginate, vinyl acetate, polyurethane resin, polyester resin, styrene-maleic anhydride copolymer alkali salt, isobutylene-maleic anhydride copolymer alkali salt, polyacrylic acid, sodium polyacrylic acid, polyacrylic acid ester , Polymethacrylic acid ester, polyacrylamide, polybutylmethacrylate, acrylamide-acrylic acid ester copolymer, acrylamide-acrylic acid ester-methacrylic acid ternary copolymer, etc. Examples thereof include, but are not limited to, based resins, vinyl chloride-vinyl acetate copolymers, ethylene-vinyl acetate copolymers, styrene-butadiene copolymers, and styrene-butadiene-acrylic copolymers. The above-mentioned binder component may be used alone or in combination of two or more. As the binder component of the heat-sensitive layer, it is recommended to use a binder component that is dissolved in water or dispersed or emulsionized in water because the leuco dye or color developer dissolves in alcohol or other organic solvent and reacts. preferable.

A sensitivity improver may be added to the heat-sensitive layer of the present invention in order to improve the printing sensitivity, if necessary. For example, fatty acids such as stearic acid and bechenic acid, fatty acid amides such as stearic acid amide and palmitate amide, fatty acid metal salts such as zinc stearate, aluminum stearate, calcium stearate, zinc palmitate and zinc behenate, p. -Benzylbiphenyl, terphenyl, triphenylmethane, benzyl p-benzyloxybenzoate, β-benzyloxynaphthalene, β-naphthoic acid phenyl ester, 1-hydroxy-2-naphthoic acid phenyl ester and the like can be used.

The heat-sensitive layer of the present invention contains, if necessary, surfactants, waxes such as vegetable wax, mineral wax, petroleum wax, synthetic wax, etc., to the extent that the basic performance of the heat-sensitive layer is not impaired. Fine powder of inorganic fillers such as calcium carbonate, silica, zinc oxide, titanium oxide, aluminum hydroxide, zinc hydroxide, barium sulfate, clay, kaolin, talc, silica, polyethylene resin, styrene acrylic copolymer resin, polystyrene resin , Polyethylene resin, vinylidene chloride resin and other auxiliary additive components such as fine powder of organic filler can be appropriately used.

In the heat-sensitive layer coating material of the present invention, leuco dyes and color-developing agents dissolve in alcohol and other organic solvents and react with each other. Therefore, various known materials for the heat-sensitive layer are known using water as a solvent or a dispersion medium. It is produced as a water-based paint by stirring and mixing by a method and dispersing if necessary.

The heat-sensitive layer of the heat-sensitive recording body of the present invention is provided by applying a paint for a heat-sensitive layer on a transparent film substrate by various known coating methods and then drying it with a hot air dryer or the like. The thickness of the heat-sensitive layer after drying is not particularly limited, but is preferably in the range of 3.0 to 15.0 μm, and more preferably in the range of 4.0 to 10.0 μm. When the thickness of the heat-sensitive layer is within the above range, it is possible to obtain a heat-sensitive recorder having a sufficient reflection density of the printed portion and excellent printing sensitivity.

<Protective layer>
The protective layer of the heat-sensitive recording body of the present invention is provided as the outermost layer of the surface provided with the transparent heat-sensitive layer of the transparent film base material, and is composed of at least a binder component, a lubricant, and calcium carbonate to provide transparency. It is characterized by having. The protective layer not only has the role of improving the durability of printing by preventing the heat-sensitive layer from coming into direct contact with the causative substance such as water, oil, or plasticizer that causes the heat-sensitive layer to lose its color development, but also has the role of improving printing durability. It must basically have the effect of suppressing the sticking phenomenon and the effect of cleaning deposits and deposits derived from the protective layer component in the thermal head. In the case of the protective layer of the thermal recording body of the present invention, in addition to the above basic roles, the visibility of printing on the thermal recording body is improved by suppressing the gloss on the protective layer side of the thermal recording body. Is also characterized by being excellent. Since it is assumed that the protective layer of the present invention is provided directly on the heat-sensitive layer, in that case, the leuco dye and the color developer contained in the heat-sensitive layer are contained in the protective layer paint, such as alcohol and the like. It is preferable that the coating material for the protective layer of the present invention is basically a water-based coating material because there is a concern that the coating material may be dissolved and reacted by the organic solvent of the above.

The binder component used for the protective layer of the present invention is not particularly limited, but various known raw materials having transparency and heat resistance may be appropriately selected and used. Specifically, a polyvinyl alcohol resin, Preferable use of polyurethane-based resin, polyester-based resin, acrylic-based resin, polystyrene-based resin, cellulose-based resin, polycarbonate resin, polyester urethane resin, acrylic urethane resin, polyamideimide resin, and silicone-modified resin of these resins. Is possible. The above-mentioned binder component may be used alone or in combination of two or more.

Among the resins that can be suitably used as the binder component of the protective layer described above, it is more preferable to use an acrylic resin that is excellent in transparency, heat resistance, water resistance, and handling as the binder component. The acrylic resin in the present invention refers to a resin composed of an acrylic acid derivative or a polymer containing a methacrylic acid derivative as a main component, and specifically, acrylic acid, methacrylic acid, and various acrylic acid esters (acrylic acid). Methyl, ethyl acrylate, propyl acrylate, isopropyl acrylate, n-butyl acrylate, t-butyl acrylate, isobutyl acrylate, pentyl acrylate, hexyl acrylate, heptyl acrylate, octyl acrylate, etc.), various methacrylic acids Acid esters (methyl methacrylate, ethyl methacrylate, propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, t-butyl methacrylate, isobutyl methacrylate, pentyl methacrylate, hexyl methacrylate, heptyl methacrylate, octyl methacrylate Etc.), various methacrylic acid amides (N-methylacrylic acid amide, N-ethylacrylic acid amide, N-propylacrylic acid amide, N-isopropylacrylic acid amide, Nn-butylacrylic acid amide, N-t-butyl Acrylic acid amide, N-isobutylacrylic acid amide, N, N-dimethylacrylic acid amide, N, N-diethylacrylic acid amide, N, N-dipropylacrylic acid amide, N, N-dibutylacrylic acid amide, etc.), Various methacrylic acid amides (N-methylmethacrylic acid amide, N-ethyl methacrylic acid amide, N-propyl methacrylic acid amide, N-isopropyl methacrylic acid amide, N-n-butyl methacrylic acid amide, N-t-butyl methacrylic acid amide) , N-isobutylmethacrylic acid amide, N, N-dimethylmethacrylic acid amide, N, N-diethylmethacrylic acid amide, N, N-dipropylmethacrylic acid amide, N, N-dibutylmethacrylic acid amide, etc.), glycidyl acrylate, etc. , A resin obtained by polymerizing various acrylic acid derivatives such as glycidyl methacrylate and one type of methacrylic acid derivative, a resin obtained by copolymerizing two or more types, and further, the various acrylic acid derivatives and methacrylic acid described above. It is copolymerized with acrylic acid, methacrylic acid, styrene, α-methylstyrene, maleic anhydride, itaconic acid, fumaric acid, etc., which are unsaturated monomers that can be copolymerized with acid derivatives as the main constituents. It may be made of resin. As the acrylic resin described above, one type may be used alone, or two or more types may be used in combination. The resin that can be suitably used as the binder component of the protective layer described above is basically dissolved in water, dispersed in water, or emulsified because it is preferable that the paint for the protective layer is basically a water-based paint. It is preferable to use the one that has been prepared.

In the protective layer of the present invention, as another binder component, in order to improve various performances of the protective layer, it is used as a binder component of the heat-sensitive layer in addition to the resin that can be suitably used as the binder component of the protective layer described above. If necessary, a small amount of the raw materials exemplified as possible may be added as long as the basic performance of the protective layer is not impaired.

The content of the binder component in the protective layer of the present invention is preferably in the range of 40 to 80% by mass of the entire protective layer, and more preferably in the range of 50 to 75% by mass of the entire protective layer. If the content of the binder component in the protective layer is less than the lower limit of the above range, the water resistance tends to decrease due to the deterioration of the film forming property of the protective layer. Due to the insufficient amount of calcium added, the sticking phenomenon tends to occur, and the effect of suppressing the gloss on the protective layer side of the thermal recording body tends to be impaired.

By further adding a cross-linking agent to the coating material for the protective layer of the present invention, a part of the binder component of the protective layer is composed of at least a cross-linked product of an acrylic resin and a cross-linking agent, thereby improving the heat resistance of the protective layer. It is possible to improve the sticking phenomenon suppression performance and further improve the water resistance. The cross-linking agent that can be used in the coating for the protective layer of the present invention is not particularly limited, and various known cross-linking agents can be used. For example, an isocyanate-based cross-linking agent, a melamine-based cross-linking agent, an aziridine-based cross-linking agent, and an epoxy-based cross-linking agent can be used. A cross-linking agent, an oxazoline-based cross-linking agent, a carbodiimide-based cross-linking agent, etc. can be used. It is most preferable to use a polyamide / epichlorohydrin resin because it is also excellent. The above-mentioned cross-linking agent may be used alone or in combination of two or more. As the cross-linking agent used for the protective layer, it is preferable that the coating material for the protective layer is basically a water-based paint, and therefore it is preferable to use a cross-linking agent resin that is soluble in water or dispersible in water.

The amount of the cross-linking agent added to the coating material for the protective layer of the present invention is not particularly limited, but it can be added in the range of 100: 5 to 100:30 in terms of the mass ratio of the solid content of the binder component and the cross-linking agent. It is preferable, and more preferably, it is added in the range of 100: 10 to 100:20. When the amount of the cross-linking agent added is within the above range, it is possible to sufficiently improve the performance such as heat resistance and water resistance by adding the cross-linking agent.

The protective layer of the heat-sensitive recording body of the present invention has a thermal head in order to improve the slipperiness between the thermal head and the protective layer during printing and to prevent the deposition and seizure of deposits composed of the protective layer component on the thermal head. It is necessary to add a lubricant in order to suppress the occurrence of sticking phenomenon at the time of printing and stabilize the printing quality by improving the cleaning property of the printing.

The lubricant used for the protective layer of the present invention is not particularly limited, and for example, various vegetable waxes such as carnauba wax, various mineral waxes such as montanic acid wax, and various petroleum waxes such as paraffin wax. , Various synthetic waxes such as Fishertropus wax and polyethylene wax and their modifications, various higher fatty acid esters such as stearic acid esters, various higher fatty acid metal salts such as zinc stearate, stearic acid amide, ethylene bisstearic acid. It is possible to appropriately select and use various known lubricants such as amide, but among these, the effect of imparting slipperiness between the thermal head and the protective layer during printing is particularly excellent, and the effect of cleaning the thermal head is further improved. It is more preferable to use zinc stearate, which is also excellent.

As the lubricant used for the protective layer described above, it is preferable that the coating material for the protective layer is a water-based paint, and therefore it is preferable to use a lubricant in a state of being finely divided and dispersed in water. _{The volume-based median diameter D 50} (JIS Z8825) measured by the laser diffraction / scattering method of the finely divided lubricant at this time is preferably in the range of 0.05 to 1.50 μm, and is 0.10 to 1. It is more preferably in the range of 00 μm. _{When the median diameter D 50 based on} the volume of the lubricant is within the above range, the effect of imparting slipperiness between the thermal head and the protective layer is excellent, and the effect of cleaning the thermal head is also excellent, so that the sticking phenomenon is suppressed as a result. The effect is also excellent. When the median diameter D _{50 based on} the volume of the lubricant is below the lower limit of the above range, the slipperiness between the thermal head and the protective layer tends to deteriorate, and conversely, the median diameter D _{50 based on} the volume of the lubricant is within the above range. If it exceeds the upper limit, the cleaning effect of the thermal head tends to decrease.

The content of the lubricant in the protective layer of the present invention is preferably 10 to 30% by mass, more preferably 15 to 25% by mass of the entire protective layer. When the content of the lubricant in the protective layer is within the above range, the effect of suppressing the sticking phenomenon is excellent and the print quality is also good. If the content of the lubricant in the protective layer is less than the lower limit of the above range, the effect of imparting slipperiness by the lubricant and the effect of cleaning the thermal head tend not to be obtained, and the sticking phenomenon tends to occur. When the content exceeds the upper limit of the above range, the film forming property of the protective layer is gradually impaired, so that the water resistance tends to decrease. In addition, it has been found that the content of the lubricant in the protective layer affects the gloss on the protective layer side of the thermal recording body, and when the content of the lubricant in the protective layer decreases, the protective layer side of the thermal recording body side. On the contrary, when the content of the lubricant in the protective layer is increased, the gloss on the protective layer side of the thermal recording body tends to be suppressed.

The protective layer of the present invention needs to be provided with a performance of improving the visibility of printing on the thermal recording body by suppressing the gloss on the protective layer side of the thermal recording body, and for that purpose, the protective layer of the protective layer It is considered necessary to add at least a so-called matting agent for suppressing the glossiness to the protective layer. Therefore, as a result of studying a matting agent to be added to the protective layer by the present inventor, if calcium carbonate is added to the protective layer, the gloss on the protective layer side of the thermal recording body is effective without deteriorating the print quality of the thermal recording body. It was found that it is possible to suppress the problem, and that it also has a slight effect of suppressing the sticking phenomenon and a cleaning effect of the thermal head, and that the wear of the thermal head is less than that of other matting agents.

The type of calcium carbonate used for the protective layer of the present invention is not particularly limited, and from the viewpoint of another production method, heavy calcium carbonate obtained by crushing and finely powdering natural limestone ore and a carbon dioxide gas reaction method or solubility There are light calcium carbonate chemically synthesized by the salt reaction method, etc., but both can be used for the protective layer of the present invention, and from the viewpoint of the particle shape of the light calcium carbonate, cubic, spindle-shaped, columnar, etc. There are needle-shaped light calcium carbonate and the like, but any of them can be used for the protective layer of the present invention.

However, as a result of repeated studies by the present inventor, with respect to heavy calcium carbonate produced by crushing natural limestone, the particle shape may be irregular or impurities with high hardness may be mixed. Due to this, the thermal head tends to wear a little more, and in the case of cubic and spindle-shaped light calcium carbonate, the dispersibility in the protective layer paint, which is a water-based paint, is slightly inferior, and the protective layer of the heat-sensitive recorder is used. It has been found that the effect of suppressing the gloss on the side tends to be slightly insufficient, and the calcium carbonate used for the protective layer of the present invention has excellent dispersibility in the protective layer paint and wear of the thermal head. It was found that it is more preferable to use columnar or needle-shaped light calcium carbonate, which is less and has an excellent effect of suppressing gloss on the protective layer side of the heat-sensitive recording body.

The columnar light calcium carbonate and needle-shaped light calcium carbonate used in the present invention have a particle shape of columnar and needle-like (sometimes referred to as fibrous) and a crystal structure mainly composed of an aragonite structure. It refers to fine particles of light calcium carbonate, and further refers to light calcium carbonate such that the aspect ratio consisting of the ratio of the major axis to the minor axis of the fine particles is in the range of 5 to 50, more preferably 8 to 20. If the aspect ratio of the columnar and needle-shaped light calcium carbonate fine particles to be used is within the above range, the performance is excellent in the dispersibility in the protective layer paint and the effect of suppressing the gloss on the protective layer side of the heat-sensitive recorder. Demonstrate.

The particle size of calcium carbonate contained in the protective layer of the present invention includes not only various optical characteristics such as gloss on the protective layer side of the thermal recording body, total light transmittance and haze of the thermal recording body, but also printing quality at the time of printing. It also affects the effect of suppressing the sticking phenomenon and the effect of cleaning the thermal head. _{The volume-based median diameter D 50} (JIS Z8825) measured by the laser diffraction / scattering method of calcium carbonate contained in the protective layer of the present invention is preferably in the range of 1.0 to 6.0 μm, preferably 1.0 to 6.0 μm. More preferably, it is in the range of 4.0 μm. If the particle size of calcium carbonate contained in the protective layer is within the above range, the effect of suppressing the gloss on the protective layer side of the thermal recording body is excellent, the printing quality at the time of printing is good, and the effect of suppressing the sticking phenomenon is further improved. It has an excellent cleaning effect on the thermal head. When the particle size of calcium carbonate is less than the lower limit of the above range, the effect of suppressing the gloss on the protective layer side of the heat-sensitive recorder tends to decrease, and the amount of fine particles of calcium carbonate exposed from the protective layer tends to decrease. As a result, the effect of suppressing the sticking phenomenon during printing and the effect of cleaning the thermal head tend to decrease. On the other hand, if the particle size of calcium carbonate exceeds the upper limit of the above range, the fine particles of calcium carbonate may hinder the heat transfer of the thermal head during printing, causing uneven shading and streaks in printing. Print quality problems such as deterioration of print sensitivity tend to occur easily.

The content of calcium carbonate in the protective layer of the present invention is preferably 10 to 25% by mass, more preferably 10 to 20% by mass of the entire protective layer. When the content of calcium carbonate in the protective layer is within the above range, the effect of suppressing the gloss on the protective layer side of the thermal recording body is excellent, the printing quality at the time of printing is good, and the effect of suppressing the sticking phenomenon and the thermal head Excellent cleaning effect. When the content of calcium carbonate in the protective layer falls below the lower limit of the above range, the gloss on the protective layer side of the heat-sensitive recorder rapidly increases, and further, the effect of suppressing the sticking phenomenon and the effect of cleaning the thermal head are slightly reduced. On the contrary, if the upper limit of the above range is exceeded, problems with print quality such as uneven shading and streaks in the print and the color of calcium carbonate being too strong and the print appearing white and muddy are likely to occur. Not only that, the cleaning effect of the thermal head is reduced because calcium carbonate itself is likely to be deposited on the thermal head, the water resistance is reduced due to the impaired film forming property of the protective layer, and the thermal is reduced. The amount of wear of the head tends to increase.

If necessary, the protective layer of the present invention is provided with various surfactants, dispersants, etc. in order to improve the pigment dispersibility, paint viscosity, and wettability of the protective layer paint so as not to impair the basic performance of the protective layer. May be added as appropriate. Further, in order to improve the light resistance of the thermal recording body, an ultraviolet absorber or an ultraviolet scattering agent may be appropriately added to the extent that the basic performance of the protective layer is not impaired.

Since it is assumed that the coating material for the protective layer of the present invention is applied directly on the heat-sensitive layer, the leuco dye or color-developing agent in the heat-sensitive layer dissolves in alcohol or other organic solvent and reacts at that time. It is preferable that the water-based coating material is produced by stirring and mixing and dispersing the various protective layer raw materials by various known methods using water as a solvent or a dispersion medium.

The protective layer of the heat-sensitive recorder of the present invention is dried by a hot air dryer or the like after applying the protective layer paint on the heat-sensitive layer or on any layer above the heat-sensitive layer by various known coating methods. Provided by. The thickness of the protective layer after drying is not particularly limited, but is preferably in the range of 0.5 to 5.0 μm, and more preferably in the range of 1.0 to 4.0 μm. When the thickness of the protective layer is within the above range, it is possible to obtain a heat-sensitive recording body which is excellent in printing sensitivity, printing quality and sticking phenomenon suppressing effect at the time of printing, and is also excellent in water resistance.

<Adhesive layer>
As shown in FIG. 2, the heat-sensitive recording material of the present invention has transparency on the surface of the transparent film base material 1 opposite to the surface provided with the heat-sensitive layer 2 so that the heat-sensitive recording material can be easily attached to a signboard or the like. The adhesive layer 5 may be provided in advance. In actual use, the heat-sensitive recording material of the present invention is often used in the form of a roll or a sheet, and in that case, when the adhesive layer 5 and the protective layer 3 are in direct contact with each other, the adhesive layer 5 and the protective layer 3 are used. 3 causes blocking, the component contained in the adhesive layer 5 migrates to the protective layer 3 and has an adverse effect, or the component contained in the adhesive layer 5 migrates to the protective layer 3 and then further penetrates the protective layer 3. Since there is a possibility of adversely affecting the leuco dye and the color developer contained in the thermal layer 2, a separator such as a release paper is generally attached to the outside of the transparent film base material 1 of the adhesive layer 5. It is often used by laminating them together.

The pressure-sensitive adhesive used for the pressure-sensitive adhesive layer of the heat-sensitive recording body of the present invention is not particularly limited, and various known pressure-sensitive adhesives such as rubber-based pressure-sensitive adhesives, acrylic-based pressure-sensitive adhesives, urethane-based pressure-sensitive adhesives, and silicone-based pressure-sensitive adhesives can be used. It may be appropriately selected and used according to the required quality, but due to the nature of the present invention, it is preferable to use a colorless and transparent adhesive as much as possible among the various adhesives described above.

The method for forming the pressure-sensitive adhesive layer of the present invention is not particularly limited, and the pressure-sensitive adhesive layer is provided by appropriately selecting various known forming methods depending on the type of pressure-sensitive adhesive. The thickness of the pressure-sensitive adhesive layer of the present invention is not particularly limited, but is preferably in the range of 5.0 to 50.0 μm, and preferably in the range of 10.0 to 30.0 μm.

Next, the present invention will be specifically described with reference to Examples and Comparative Examples, but the present invention is not limited to the Examples.

<< Method of manufacturing a thermal recording body >>
The method for producing the thermal recording body used in Examples and Comparative Examples will be described in detail below.

Table 1 shows the details of each raw material used for the protective layer of the thermal recording body used in Examples and Comparative Examples, and the details of the blending ratio of the protective layer paint for each Example and Comparative Example.

<Preparation of thermal recording body of Example 1>
A transparent PET film with a thickness of 38 μm, total light transmittance of 89%, and haze of 5.5% is used as the base material 1, and a transparent grade heat-sensitive coloring paint manufactured by Nippon Kayaku Co., Ltd. is applied to the upper layer with a bar coater, dried, and dried. A heat-sensitive layer having a thickness of 6.0 μm was provided later. Next, according to the coating ratio for the protective layer of Formulation 1 shown in Table 1, various raw materials are weighed and put into a container, and the protective layer is sufficiently stirred and mixed with a stirrer until all are uniformly mixed. In Example 1, a paint (formulation 1) was prepared, a protective layer paint (formulation 1) was applied onto the heat-sensitive layer described above with a bar coater, dried, and a protective layer having a thickness of 2.0 μm after drying was provided. A heat-sensitive recorder to be used was prepared.

<Preparation of thermal recording body of Example 2>
A protective layer paint (formulation 2) was prepared by removing a cross-linking agent from the binder component of the protective layer paint (formulation 1) used in Example 1, and the protective layer paint used in Example 1 was prepared. A heat-sensitive recorder used in Example 2 was prepared, which is the same as the heat-sensitive recorder of Example 1 except that it was replaced with (Formulation 1).

<Preparation of thermal recording body of Example 3>
A protective layer paint (formulation 3) was prepared by replacing the columnar light calcium carbonate added to the protective layer paint (formulation 1) used in Example 1 with a spindle-shaped light calcium carbonate, and this was used in Example 1. The heat-sensitive recording material used in Example 3 was prepared, which is the same as the heat-sensitive recording material of Example 1 except that it was replaced with the protective layer paint (formulation 1) used in.

<Preparation of thermal recording bodies of Comparative Examples 1 to 3>
The columnar light calcium carbonate added to the protective layer paint (formulation 1) used in Example 1 was replaced with synthetic silica, talc, and mica, respectively, to prepare protective layer paints (formulations 4 to 6), and they were prepared. The heat-sensitive recording materials used in Comparative Examples 1 to 3 were prepared, which are the same as the heat-sensitive recording materials of Example 1 except that the above was replaced with the protective layer paint (formulation 1) used in Example 1.

<Preparation of thermal recording body of Comparative Example 4>
Comparative Example 4 which is the same as the thermal recording body of Example 1 except that the base material 1 of Example 1 is replaced with the base material 2 which is a PP film having a thickness of 200 μm, a total light transmittance of 70%, and a haze of 85%. The thermal recording bodies used in the above were prepared respectively.

<Preparation of thermal recording body of Comparative Example 5>
Example 1 except that a protective layer paint (formulation 7) in which calcium carbonate is not added to the protective layer paint formulation was prepared and replaced with the protective layer paint (formulation 1) used in Example 1. A thermal recorder used in Comparative Example 5, which is the same as the thermal recorder, was prepared.

<Preparation of thermal recording body of Comparative Example 6>
Except for the fact that a protective layer paint (formulation 8) in which no lubricant (zinc stearate) was added to the protective layer paint formulation was prepared and replaced with the protective layer paint (formulation 1) used in Example 1. A heat-sensitive recorder used in Comparative Example 6, which is the same as the heat-sensitive recorder of Example 1, was prepared.

<Preparation of thermal recording bodies of Examples 4 to 9>
Protective layer paints (blending 9 to 14) in which the amounts of columnar light calcium carbonate and zinc stearate added to the protective layer paint were changed were prepared, and the protective layer paints (blending) used in Example 1 were prepared. The heat-sensitive recorders used in Examples 4 to 9, which are the same as the heat-sensitive recorders of Example 1 except that they were replaced with 1), were prepared.

<< Evaluation of thermal recorder >>
Various evaluations were carried out for each thermal recording body prepared for Examples and Comparative Examples by the methods shown below. As for Comparative Example 3, some evaluations were not performed because the print quality was not very good.

<Evaluation of print quality>
The print quality of the thermal recorder was tested under the following conditions, and the print quality of the thermal recorder was evaluated according to the following evaluation criteria.
(Test conditions)
Using a Zebra printer "Zebra140XiII", a heat-sensitive recorder with a printing speed of 76.2 mm / sec and a printing density of 15/30 has a width of 5 cm and a length of 2 cm (5 cm in the direction parallel to the thermal head, printing flow direction). A solid black print of 2 cm) was printed, and the print was visually observed for evaluation.
(Evaluation criteria)
A ... The color of the print was good, and no uneven shading, streaks, voids, etc. were observed.
B ... The color of the print is slightly poor or the print is slightly cloudy, and uneven shading, sujimura, voids, etc. are slightly observed.
C ... The color of the print is clearly poor or the print is clearly cloudy, and uneven shading, sujimura, voids, etc. are clearly seen.
D ... The color of the print is very poor or the print is very cloudy, and uneven shading, sujimura, voids, etc. are severely seen.

<Evaluation of print visibility>
A test was conducted on the print visibility of the thermal recorder under the following conditions, and the results were evaluated on the print visibility of the thermal recorder according to the following evaluation criteria.
(Test conditions)
Using the Zebra 140XiII printer, 1dot characters are printed on the thermal recorder under the conditions of a printing speed of 76.2 mm / sec and a printing density of 15/30, and a position 10 cm away from the printed part at an incident angle of 60 degrees. The print was visually observed and evaluated at a position of a reflection angle of 60 degrees when an LED flashlight of about 1000 lumens was applied.
(Evaluation criteria)
A ... The specular reflection of light was weak and there was no problem in recognizing 1dot characters.
B ... I was worried about the specular reflection of light, but there was not much problem in recognizing 1dot characters.
C ... The specular reflection of light was strong, and it was a little difficult to recognize 1 dot characters.
D ... The specular reflection of light was too strong to recognize 1dot characters at all.

<Evaluation of transparency>
In order to evaluate the transparency of the thermal recording body, more specifically, to evaluate whether the design on the back of the thermal recording body can be seen well, a test was conducted under the following conditions, and the results were evaluated as follows. The transparency of the thermal recorder was evaluated according to the criteria.
(Test conditions)
The heat-sensitive recording body of the present invention was attached to a wood-grain signboard using a transparent adhesive, and the evaluation was carried out by visually observing it from the heat-sensitive recording body side.
(Evaluation criteria)
A ... The wood grain of the wood grain signboard is clearly visible.
B ... The wood grain of the wood grain signboard looks good, but the whole looks slightly white and blurry.
C ... The wood grain of the wood grain signboard does not look very good, and the whole looks white and blurry.
D ... I can't see the grain of the wood grain signboard

<Evaluation of the effect of suppressing the sticking phenomenon>
The test was conducted under the following conditions for the effect of suppressing the sticking phenomenon of the thermal recording body, and the result was evaluated by the following evaluation criteria for the effect of suppressing the sticking phenomenon of the heat-sensitive recording body.
(Test conditions)
Using the Zebra printer "Zebra140XiII", print solid black with a width of 5 cm and a length of 2 cm on a thermal recorder under the conditions of a printing speed of 76.2 mm / sec and a printing density of 20/30. Evaluation was performed by observing visually.
(Evaluation criteria)
A: There is no unevenness in shading or uneven melting of the protective layer in the solid black print portion.
B ... There is slight unevenness in shading and uneven melting of the protective layer in the solid black print area.
C: Uneven shading and uneven melting of the protective layer are clearly visible in the solid black print area.
D ... The black solid printed portion has severe shading unevenness, melting unevenness of the protective layer, etc., and abnormal color development of the heat-sensitive layer and peeling of the protective layer are also observed.

<Evaluation of thermal head cleaning effect>
A test was conducted on the cleaning effect of the thermal head of the thermal recording body under the following conditions, and the cleaning effect of the thermal head of the thermal recording body was evaluated based on the following evaluation criteria.
(Test conditions)
Using the Zebra printer "Zebra140XiII", solid black printing with a width of 5 cm and a length of 2 cm was continuously printed 100 times on a thermoelectric recorder under the conditions of a printing speed of 76.2 mm / sec and a printing density of 20/30. After the thermal head was sufficiently cooled, the cellophane tape was attached to the electric heating element portion of the thermal head and then peeled off, and the deposits adhering to the cellophane tape were visually observed and evaluated.
(Evaluation criteria)
A ... No thermal head deposits or deposits have adhered to the cellophane tape.
B ... There is a slight amount of thermal head deposits and deposits on the cellophane tape.
C ... The deposits and deposits of the thermal head are clearly attached to the cellophane tape.
D ... A large amount of thermal head deposits and deposits are attached to the cellophane tape.

<Evaluation of water resistance>
The water resistance of the heat-sensitive recording material was tested under the following conditions, and the results were evaluated for the water resistance of the heat-sensitive recording material according to the following evaluation criteria.
(Test conditions)
Using the Zebra 140XiII printer, a thermal recorder with a printing speed of 76.2 mm / sec and a printing density of 15/30 has a width of 5 cm and a length of 2 cm (5 cm in the direction parallel to the thermal head, printing flow direction). 2 cm) of solid black printing is performed, and the black solid printed part of the thermal recording body is visually observed after being left to stand at room temperature for 24 hours with the printed thermal recording body completely immersed in purified water. It was observed and evaluated in.
(Evaluation criteria)
A: There is no change in color or abnormality in the solid black printed portion before and after the water resistance test.
B ... Slight color change or abnormality is observed in the solid black printed portion before and after the water resistance test.
C ... Before and after the water resistance test, a color change or abnormality in the solid black printed portion is clearly seen.
D: Before and after the water resistance test, color change or abnormality of the solid black printed portion is remarkably observed.

Table 2 shows various evaluation results of the heat-sensitive recorders of Examples 1 to 3 and Comparative Examples 1 to 4 of the present invention.

Table 3 shows various evaluation results of the thermal recording bodies of Examples 4 to 9 and Comparative Examples 5 and 6 of the present invention.

As shown in Examples 1 to 9, a surface provided with a transparent heat-sensitive layer composed of at least a leuco dye, a color developer, and a binder component on one surface of the transparent film base material, and further provided with a heat-sensitive layer. It is a thermal recording body provided with at least a transparent protective layer composed of a binder component, a lubricant and calcium carbonate on the outermost layer of the thermal recording body, and has a 60-degree mirror glossiness on the protective layer side of the thermal recording body. If the heat-sensitive recording material has a haze of 40 or less, a heat-sensitive recording body haze of 85% or less, and a total light transmittance of the heat-sensitive recording body of 70% or more, the print quality, the effect of suppressing the sticking phenomenon, and the effect of cleaning the thermal head It can be seen that the basic performance of the thermal recording body is excellent, and while it has transparency and water resistance, it is also excellent in the visibility of printing.

When silica was used instead of calcium carbonate as the matting agent constituting the protective layer as in Comparative Example 1, the gloss on the protective layer side of the thermal recording body could be greatly suppressed, but the appearance of the print became whitish or the print was printed. The print quality deteriorated, such as the reflection density of the portion falling below 1.50.

When talc was used instead of calcium carbonate as the matting agent constituting the protective layer as in Comparative Example 2, there was no problem in printing quality, etc., but the effect of suppressing the gloss on the protective layer side of the thermal recording body was obtained. It was poor and the visibility of printing deteriorated.

When mica is used instead of calcium carbonate as the matting agent constituting the protective layer as in Comparative Example 3, the print quality tends to be significantly impaired, for example, a large number of voids are generated when solid printing is performed. It was.

When a film base material having a low total light transmittance and a high haze was used as the base material of the heat-sensitive recording body as in Comparative Example 4, the transparency of the heat-sensitive recording body deteriorated, and the back surface of the heat-sensitive recording body became I couldn't see a certain design or thing satisfactorily.

As in Comparative Example 5, if calcium carbonate, which is a matting agent, was not added to the protective layer at all, the effect of suppressing the gloss on the protective layer side of the thermal recording body was poor, and the visibility of printing was greatly deteriorated.

If no lubricant is added to the protective layer as in Comparative Example 6, a sticking phenomenon occurs violently during printing, and as a result, the surface of the protective layer becomes rough due to melting or the like, and the protective layer becomes transparent. Not only does the print appear white and muddy due to impaired properties and the protective function of the heat-sensitive layer of the protective layer, but also voids occur in the print, and the reflection density of the printed part is less than 1.50. Significant deterioration was observed, and the effect of suppressing gloss on the protective layer side of the thermal recording body was also impaired, so that the visibility of printing was also significantly deteriorated.

The heat-sensitive recorder in the present invention is used for temporary outdoor and indoor signs such as hotel welcome and farewell signs and signboards for condolences, food labels and food packaging materials, various general distribution management labels, and various name tags. It can be used for labels, labels for various addresses, etc.

1; Transparent film base material 2; Thermal layer 3; Protective layer 4; Thermal recorder 5; Adhesive layer

Claims (9)

A transparent heat-sensitive layer composed of at least a leuco dye, a developer, and a binder component on one surface of the transparent film base material, and a binder component, a lubricant, and carbon dioxide on the outermost layer of the surface further provided with the heat-sensitive layer. A thermal recording body provided with at least a transparent protective layer composed of calcium, wherein the 60-degree mirror surface gloss (JIS Z8741) on the protective layer side of the thermal recording body is 40 or less and the thermal recording is performed. A heat-sensitive recording body having a body haze (JIS K7136) of 85% or less and a total light transmittance (JIS K7361-1) of the heat-sensitive recording body of 70% or more. The thermal recording body according to claim 1, wherein the protective layer contains calcium carbonate in the range of 10 to 25% by mass of the entire protective layer and the lubricant in the range of 10 to 30% by mass of the entire protective layer. The heat-sensitive recorder according to claim 1 or 2, wherein the calcium carbonate constituting the protective layer is columnar light calcium carbonate or needle-shaped light calcium carbonate. The invention according to any one of claims 1 to 3, wherein _{the volume-based median diameter D 50} (JIS Z8825) measured by the laser diffraction / scattering method of calcium carbonate constituting the protective layer is in the range of 1.0 to 6.0 μm. Heat-sensitive recorder. The heat-sensitive recorder according to any one of claims 1 to 4, wherein the lubricant constituting the protective layer is zinc stearate. The heat-sensitive recorder according to any one of claims 1 to 5, wherein the binder component constituting the protective layer is at least a crosslinked product of an acrylic resin and a crosslinking agent. The heat-sensitive recorder according to any one of claims 1 to 6, wherein the cross-linking agent is a polyamide / epichlorohydrin resin. The heat-sensitive recorder according to any one of claims 1 to 7, wherein the 60-degree mirror gloss (JIS Z8741) of the printed portion is 50 or less. The heat-sensitive recorder according to any one of claims 1 to 8, wherein a transparent adhesive layer is provided on a surface of the transparent film base material opposite to the surface on which the heat-sensitive layer is provided.

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