阅读说明：本技术 热敏记录介质、热敏记录介质生产方法和制品 (Thermosensitive recording medium, thermosensitive recording medium production method and product ) 是由 小原岳 门田康宽 于 2018-12-21 设计创作，主要内容包括：提供了一种热敏记录介质,其包括：透明基础材料；在透明基础材料上的热敏记录层；以及在热敏记录层上的阻挡层,其中阻挡层含有中空颗粒和粘合剂树脂,并且其中当从具有透明基础材料的热敏记录层的表面向热敏记录层施加热能时,热敏记录层显色。还提供了一种热敏记录介质生产方法,其包括：在透明基础材料上形成热敏记录层的步骤；以及在热敏记录介质上形成含有中空颗粒和粘合剂树脂的阻挡层的步骤。(Provided is a thermosensitive recording medium including: a transparent base material; a thermosensitive recording layer on the transparent base material; and a barrier layer on the thermosensitive recording layer, wherein the barrier layer contains hollow particles and a binder resin, and wherein the thermosensitive recording layer develops color when thermal energy is applied to the thermosensitive recording layer from a surface of the thermosensitive recording layer having the transparent base material. Also provided is a thermosensitive recording medium production method including: a step of forming a thermosensitive recording layer on a transparent base material; and a step of forming a barrier layer containing the hollow particles and the binder resin on the thermosensitive recording medium.)

1. A thermosensitive recording medium, comprising:

a transparent base material;

a thermosensitive recording layer on the transparent base material; and

a barrier layer on the thermosensitive recording layer,

wherein the barrier layer comprises hollow particles and a binder resin, and

wherein the thermosensitive recording layer develops color when thermal energy is applied to the thermosensitive recording layer from the surface of the thermosensitive recording layer having the transparent base material.

2. The thermosensitive recording medium according to claim 1,

wherein the barrier layer comprises at least any one selected from the group consisting of: polyvinyl acetate, polyurethane, polyacrylic acid, polyacrylate, vinyl chloride-vinyl acetate copolymer, polybutyl methacrylate, ethylene-vinyl acetate copolymer, styrene-butadiene copolymer, and styrene-butadiene-acrylic acid copolymer.

3. The thermosensitive recording medium according to claim 1 or 2,

wherein the transparent base material has an average thickness of 4 microns or more but 25 microns or less.

4. The thermosensitive recording medium according to any one of claims 1 to 3,

wherein the transparent base material comprises polyethylene terephthalate.

5. The thermosensitive recording medium according to any one of claims 1 to 4, further comprising

An adhesion promoter layer on the barrier layer.

6. The thermosensitive recording medium according to any one of claims 1 to 5, further comprising

A heat-resistant layer on a surface of the transparent base material opposite to a surface of the transparent base material having the thermosensitive recording layer.

7. The thermosensitive recording medium according to claim 6,

wherein the heat-resistant layer contains at least any one of itaconic acid-modified polyvinyl alcohol and polyamide epichlorohydrin resin.

8. The thermosensitive recording medium according to claim 6 or 7,

wherein at least any one of the transparent base material, the thermosensitive recording layer, and the heat-resistant layer includes an ultraviolet absorber.

9. The thermosensitive recording medium according to any one of claims 1 to 8,

wherein the amount of the barrier layer adhered is 0.5g/m²Or greater but 10.0g/m²Or smaller.

10. The thermosensitive recording medium according to any one of claims 1 to 9,

wherein the hollow particles have a hollow ratio of 45% or more.

11. The thermosensitive recording medium according to any one of claims 5 to 10, comprising

A release paper on the tackifier layer.

12. The thermosensitive recording medium according to any one of claims 1 to 10, comprising

A release layer on the transparent base material.

13. A method for producing a thermosensitive recording medium, comprising:

forming a thermosensitive recording layer on a transparent base material; and

a barrier layer including hollow particles and a binder resin is formed on the thermosensitive recording layer.

14. An article of manufacture comprising

The thermosensitive recording medium according to any one of claims 1 to 12.

Technical Field

The invention relates to a thermosensitive recording medium, a thermosensitive recording medium production method and an article.

Background

Thermosensitive recording media are widely used in many fields such as, for example, the POS field of perishable foods, boxed lunch, and delicatessens; the field of copying of, for example, books and documents; the field of communications, such as facsimile; the field of ticketing, such as ticketing machines for the airline industry, receipts, signed receipts, and baggage tags. In addition to these uses, thermosensitive recording media are used for, for example, drug management labels, analyte management labels, and process management labels.

In particular, for use as, for example, a drug management label, an analyte management label, and a process management label, a thermosensitive recording medium having excellent properties in, for example, solvent resistance and scratch resistance is required to maintain the label on the label for a long period of time.

For example, in order to improve solvent resistance and scratch resistance, a thermosensitive recording medium including a protective layer made of a resin on a thermosensitive recording layer is proposed (for example, see PTL 1).

It has also been proposed to sequentially laminate a resin film and a silicone film on a thermosensitive recording layer to improve water resistance, oil resistance and scratch resistance (see, for example, PTL 2).

Reference list

Patent document

PTL 1: japanese unexamined patent application publication No. 2002-11956

PTL 2: japanese unexamined patent application publication No. 07-25142

Disclosure of Invention

Technical problem

An object of the present disclosure is to provide a thermosensitive recording medium having excellent solvent abrasion resistance, color development sensitivity, visibility, and temporary fade resistance.

Technical scheme

According to one aspect of the present disclosure, a thermosensitive recording medium includes a transparent base material, a thermosensitive recording layer on the transparent base material, and a barrier layer on the thermosensitive recording layer. The barrier layer contains hollow particles and a binder resin. When thermal energy is applied to the thermosensitive recording layer from the surface of the thermosensitive recording layer having the transparent base material, the thermosensitive recording layer develops color.

Advantageous effects of the invention

The present disclosure can provide a thermosensitive recording medium excellent in solvent abrasion resistance, color development sensitivity, visibility, and temporary fade resistance.

Drawings

Fig. 1 is a schematic view showing an example of a thermosensitive recording medium of the present disclosure.

Fig. 2 is a schematic view showing another example of the thermosensitive recording medium of the present disclosure.

Fig. 3 is a schematic view showing another example of the thermosensitive recording medium of the present disclosure.

Fig. 4 is a schematic view showing another example of the thermosensitive recording medium of the present disclosure.

Detailed Description

(thermal recording Medium)

The thermosensitive recording medium of the present disclosure includes a transparent base material, a thermosensitive recording layer on the transparent base material, and a barrier layer on the thermosensitive recording layer. The barrier layer comprises hollow particles and a binder resin. When light or thermal energy is applied to the thermosensitive recording layer from the surface of the thermosensitive recording layer having the transparent base material, the thermosensitive recording layer develops color. The thermosensitive recording medium further includes other layers as necessary.

The thermosensitive recording medium of the present disclosure is based on the following findings. With the existing thermosensitive recording medium, printed information may disappear over time, and commercial value may be reduced. This makes proper management without erroneous recognition, for example, in use in drug management, analyte management, and process management, difficult.

By having a layer configuration in which a transparent base material is provided to constitute the surface of the thermosensitive recording medium on the recording surface side, the solvent abrasion resistance, color development sensitivity, visibility, and temporary fade resistance of the thermosensitive recording medium of the present disclosure can be improved.

< transparent base Material >

The transparent base material is not particularly limited, and the shape, structure, average thickness, and material of the transparent base material may be appropriately selected according to the intended purpose, as long as the transparent base material has transparency to make an image printed on the thermosensitive recording layer visible and solvent resistance to an organic solvent.

In the present disclosure, transparency refers to a property defined by haze measured according to ASTM D1003 or ISO 14782. The haze is preferably 30% or less, more preferably 10% or less.

The method for measuring the haze is not particularly limited and may be appropriately selected depending on the intended purpose. Examples of such methods include a haze meter (instrument name: HZ-V3, available from Suga Test Instruments Co., Ltd.).

In the present disclosure, solvent resistance mainly refers to resistance to organic solvents. Examples of the organic solvent include alcohols such as ethanol, methanol, butanol and propanol; ketones such as acetone and MEK (methyl ethyl ketone); aromatic hydrocarbons such as toluene and xylene; and esters such as ethyl acetate and butyl acetate. One of these organic solvents may be used alone, or two or more of these organic solvents may be used in combination.

The material of the transparent base material is not particularly limited as long as the material has the above-mentioned solvent resistance. Examples of the material include inorganic materials, organic materials, and inorganic-organic hybrid materials. Here, examples of the organic material include a film made of a plastic material such as a polyester resin or the like, such as polyethylene terephthalate (PET), polycarbonate, Polystyrene (PS), polymethyl methacrylate (PMMA), Polyethylene (PE), and polypropylene (PP) (hereinafter, referred to as a plastic film). One of these organic materials may be used alone, or two or more of these organic materials may be used in combination. Among these organic materials, polyethylene terephthalate (PET) and polypropylene (PP) are preferable in terms of flexibility. In particular, in the case where heat is applied to the heat-sensitive recording layer through the transparent base material during printing, polyethylene terephthalate (PET) excellent in heat resistance is more preferable. A thermosensitive recording medium excellent in head-matching properties can be obtained using polyethylene terephthalate (PET).

The heat-resistant layer may be formed on the transparent base material using, for example, a cured resin obtained by curing at least one of a monomer, an oligomer, and a polymer, or a combination of two or more thereof, including, for example, a water-soluble resin such as polyvinyl alcohol and modified polyvinyl alcohol, a water-dispersible resin such as acrylic emulsion, acrylic ester, methacrylic ester, vinyl ester, a styrene derivative, a silicone resin, and an aryl compound.

As the modified polyvinyl alcohol, for example, carboxyl-modified polyvinyl alcohols such as itaconic acid-modified polyvinyl alcohol, sulfonic acid-modified polyvinyl alcohol, silicone-modified polyvinyl alcohol, and other modified polyvinyl alcohols can be suitably used.

As the filler, the heat-resistant layer may contain inorganic pigments such as calcium carbonate, silica, aluminum hydroxide, zinc oxide, titanium oxide, zinc hydroxide, barium sulfate, clay, kaolin, talc, and surface-treated calcium, and surface-treated silica, or organic powders such as acrylic resin, urea-formaldehyde resin (urea-formaline resin), styrene-methacrylic acid copolymer, polystyrene resin, and vinylidene chloride resin. Further, as a crosslinking agent for, for example, polyvinyl alcohol and modified polyvinyl alcohol, the heat-resistant layer may contain glyoxal derivatives, hydroxymethyl derivatives, epichlorohydrin derivatives, epoxy compounds, aziridine compounds, hydrazine, and hydrazide derivatives. Among these materials, a combination of the modified polyvinyl alcohol and the polyamide resin with an inorganic pigment such as calcium carbonate and aluminum hydroxide is preferable.

The heat-resistant layer may further contain an ultraviolet absorber.

By providing the heat-resistant layer, head matching property and printability can be improved. The thickness of the heat-resistant layer is preferably 0.1 micrometers or more but 1.5 micrometers or less.

The transparent base material may suitably contain an ultraviolet absorber such as a benzotriazole-based compound, a triazine-based compound, a benzophenone-based compound and a hindered amine-based compound, and other additives. One of these additives may be used alone, or two or more of these additives may be used in combination.

The shape of the transparent base material is not particularly limited and may be appropriately selected depending on the intended purpose. Examples of the shape of the transparent base material include polygons such as squares and rectangles, circles, ovals, flat plates, sheets, and rolls.

The average thickness of the transparent base material may be appropriately selected depending on, for example, the use and material of the thermosensitive recording medium. When a plastic film is used as the transparent base material, the average thickness of the transparent base material is preferably 4 micrometers or more but 25 micrometers or less, more preferably 6 micrometers or more but 20 micrometers or less, and further preferably 10 micrometers or more but 16 micrometers or less. When the average thickness of the transparent base material is 4 micrometers or more but 25 micrometers or less, the thermosensitive recording medium can be produced with good operability maintained, and the heat from the print head can be appropriately conducted to the thermosensitive recording layer during printing.

In order to improve the adhesion of the thermosensitive recording layer to the transparent base material, it is preferable to surface reform the transparent base material by, for example, corona discharge treatment, oxidation reaction treatment (e.g., chromic acid), etching treatment, treatment for imparting easy tackiness, antistatic treatment, and the like. Further, examples of methods for improving the adhesiveness of the thermosensitive recording layer include the following methods in addition to these surface reforming methods: a layer (easy-adhesion layer) containing a styrene-butadiene copolymer alone, or an acrylic-based aqueous emulsion or a urethane-based aqueous emulsion, or a copolymer or a mixture of an acrylic-based aqueous emulsion and a urethane-based aqueous emulsion is formed on a transparent base material, and then a thermosensitive recording layer is formed on the easy-adhesion layer. By providing the easy-adhesion layer, peeling of the film can be prevented.

< thermosensitive recording layer >

The thermosensitive recording layer contains a leuco dye, a color developer, and a binder resin, and further contains other components as necessary.

Leuco dyes-

The leuco dye is not particularly limited and may be appropriately selected depending on the intended purpose. Examples of leuco dyes include leuco compounds used for such dyes as triphenylmethane, fluoran, phenothiazinyl, auramine, spiropyranyl and indoline phthalenyl dyes. One of these leuco dyes may be used alone, or two or more of these leuco dyes may be used in combination.

Examples of colorless compounds include 3, 3-bis (p-dimethylaminophenyl) -phthalide, 3, 3-bis (p-dimethylaminophenyl) -6-dimethylaminophthalide (also known as crystal violet lactone), 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-diethylamino-7-chlorofluorane, 3-diethylamino-7-methylfluorane, 3-diethylamino-7, 8-benzofluoran, 3-diethylamino-6-methyl-7-chlorofluoran, 3- (N-p-tolyl-N-ethylamino) -6-methyl-7-anilinofluoran, 2- { N- (3' -trifluoromethylphenyl) amino } -6-diethylaminofluoran, 2- {3, 6-bis (diethylamino) -9- (o-chloroanilino) xanthylide benzoate }, 3-diethylamino-6-methyl-7- (m-trichloromethylanilino) fluoran, 3-diethylamino-7- (o-chloroanilino) fluoran, 3-pyrrolidinyl-6-methyl-7-anilinofluoran, 3-diethylamino-e, 6-methyl-7-anilinofluoran, and mixtures thereof, 3-di-N-butylamino-7-o-chloroanilino) fluoran, 3-N-methyl-N, N-pentylamino-6-methyl-7-anilinofluoran, 3-N-methyl-N-cyclohexylamino-6-methyl-7-anilinofluoran, 3-diethylamino-6-methyl-7-anilinofluoran, 3- (N, N-diethylamino) -5-methyl-7- (N, N-dibenzylamino) fluoran, benzoyl leuco methylene blue, 6 '-chloro-8' -methoxy-benzindolinyl-spiropyran, 6 '-bromo-3' -methoxy-benzindolinyl-spiropyran, 6 '-chloro-8' -methoxy-benzindolinyl-spiropyran, 3- (2' -hydroxy-4 ' -dimethylaminophenyl) -3- (2' -methoxy-5 ' -chlorophenyl) phthalide, 3- (2' -hydroxy-4 ' -dimethylaminophenyl) -3- (2' -methoxy-5 ' -nitrophenyl) phthalide, 3- (2' -hydroxy-4 ' -diethylaminophenyl) -3- (2' -methoxy-5 ' -methylphenyl) phthalide, 3- (2' -methoxy-4 ' -dimethylaminophenyl) -3- (2' -hydroxy-4 ' -chloro-5 ' -methylphenyl) phthalide, 3- (N-ethyl-N-tetrahydrofurfuryl) amino-6-methyl-7- Anilinofluoran, 3-N-ethyl-N- (2-ethoxypropyl) amino-6-methyl-7-anilinofluoran, 3-N-methyl-N-isobutyl-6-methyl-7-anilinofluoran, 3-morpholinyl-7- (N-propyl-trifluoromethylanilino) fluoran, 3-pyrrolidinyl-7-trifluoromethylanilinofluoran, 3-diethylamino-5-chloro-7- (N-benzyl-trifluoromethylanilino) fluoran, 3-pyrrolidinyl-7- (di-p-chlorophenyl) methylaminofluoran, 3-diethylamino-5-chloro-7- (alpha-phenylethylamino) fluoran, beta-methyl-anilinofluoran, beta-methyl anilinofl, 3- (N-ethyl-p-tolylamino) -7- (. alpha. -phenylethylamino) fluoran, 3-diethylamino-7- (o-methoxycarbonylphenylamino) fluoran, 3-diethylamino-5-methyl-7- (. alpha. -phenylethylamino) fluoran, 3-diethylamino-7-piperidinofluoran, 2-chloro-3- (N-methyltolyl) -7- (p-N-butylaniline) fluoran, 3-di-N-butylamino-6-methyl-7-anilinofluoran, 3, 6-bis (dimethylamino) fluorenemo (9,3') -6' -dimethylaminobenzephthalide, 3- (N-benzyl-N-cyclohexylamino) -5, 6-benzo-7-alpha-naphthylamino-4 ' -bromofluorane, 3-diethylamino-6-chloro-7-anilinofluorane, 3-diethylamino-6-methyl-7-meditidino-4 ',5' -benzofluorane, 3-N-methyl-N-isopropyl-6-methyl-7-anilinofluorane, 3-N-ethyl-N-isopentyl-6-methyl-7-anilinofluorane, 3-diethylamino-6-methyl-7- (2', 4' -dimethylanilino) fluorane, 3-diethylamino-5-chloro- (alpha-phenylethylamino) fluorane, 3-diethylamino-7-piperidinofluorane, 3- (N-benzyl-N-cyclohexylamino) -5, 6-benzo-7-alpha-naphthylamino-4' -bromofluorane, 3-N-ethyl-N-tetrahydrofurfurylamino-6-methyl-7-anilinofluorane, 3- (p-dimethylaminophenyl) -3- {1, 1-bis (p-dimethylaminophenyl) ethylidene-2-yl } phthalide, 3- (p-dimethylaminophenyl) -3- {1, 1-bis (p-dimethylaminophenyl) ethylidene-2-yl } -6-dimethylaminophthalide, 3- (p-dimethylaminophenyl) -3- (1-p-naphthoic acid Dimethylaminophenyl-1-phenylethylidene-2-yl) phthalide, 3- (p-dimethylaminophenyl) -3- (1-p-dimethylaminophenyl-1-p-chlorophenylethylidene-2-yl) -6-dimethylaminophthalide, 3- (4 '-dimethylamino-2' -methoxy) -3- (1 "-p-dimethylaminophenyl-1" -p-chlorophenyl-1 ", 3" -butan-4 "-yl) phthalide, 3- (4 '-dimethylamino-2' -benzyloxy) -3- (1" -p-dimethylaminophenyl-1 "-phenyl-1", 3 '-butadiene-4' -yl) phthalide, 3-dimethylamino-6-dimethylamino-fluorene-9-spiro-3 '- (6' -dimethylamino) phthalide, 3-bis (2- (p- (dimethylaminophenyl) -2-p-methoxyphenyl) vinyl) -4,5,6, 7-tetrachlorophthalide, 3-bis {1, 1-bis (4-pyrrolidinylphenyl) ethylidene-2-yl } -5, 6-dichloro-4, 7-dibromophthalein, bis (p-dimethylaminostyryl) -1-naphthalenesulfonylmethane, and bis (p-dimethylaminostyryl) -1-p-toluenesulfonylmethane.

50% cumulative volume particle diameter (D) of leuco dye₅₀) Preferably 0.1 micron or more but 0.5 micron or less, and more preferably 0.1 micron or more but 0.4 micron or less.

The method for measuring the 50% cumulative volume particle diameter (D50) of the leuco dye is not particularly limited and may be appropriately selected depending on the intended purpose. Examples of such methods include laser diffraction/scattering particle size distribution measuring instruments (instrument name: LA-920, available from Horiba, Ltd.).

The content of the leuco dye is not particularly limited, may be appropriately selected according to the intended purpose, and when the total amount of the thermosensitive recording layer is 100 parts by mass, it is preferably 5 parts by mass or more but 40 parts by mass or less, and more preferably 10 parts by mass or more but 30 parts by mass or less.

-color-developing agents

As the color-developer, various electron-accepting substances that react with the leuco dye upon heating the leuco dye to develop the color of the leuco dye can be used.

The developer is not particularly limited and may be appropriately selected depending on the intended purpose. Examples of the color developer include phenolic substances, organic acidic substances, inorganic acidic substances, and esters or salts of these substances.

Examples of the color developer include gallic acid, salicylic acid, 3-isopropylsalicylic acid, 3-cyclohexylsalicylic acid, 3, 5-di-tert-butylsalicylic acid, 3, 5-di-alpha-methylbenzylsalicylic acid, 4' -isopropylidenediphenol, 1' -isopropylidenebis (2-chlorophenol), 4' -isopropylidenebis (2, 6-dibromophenol), 4' -isopropylidenebis (2, 6-dichlorophenol), 4' -isopropylidenebis (2-methylphenol), 4' -isopropylidenebis (2, 6-dimethylphenol), 4-isopropylidenebis (2-tert-butylphenol), 4' -sec-butylidenebis, 4' -cyclohexylidenebis, 4' -isopropylidenebis (2-butylphenol), 4' -isopropylidenebis (2-tert-butylphenol), 4' -sec-butylidenebis (4, 6-dimethylphen, 4,4' -cyclohexylidenebis (2-methylphenol), 4-tert-butylphenol, 4-phenylphenol, 4-hydroxybenzophenol, alpha-naphthol, beta-naphthol, 3, 5-xylenol, thymol, methyl-4-hydroxybenzoate, 4-hydroxyacetophenone, novolak-type phenol resin, 2' -thiobis (4, 6-dichlorophenol), catechol, resorcinol, hydroquinone, pyrogallol, phloroglucinol carboxylic acid, 4-tert-octylcatechol, 2' -methylenebis (4-chlorophenol), 2' -methylenebis (4-methyl-6-tert-butylphenol), 2-dihydroxybiphenyl, 2,4' -dihydroxydiphenylsulfone, 4,4'- [ oxybis (ethyleneoxy-p-phenylenesulfonyl) ] diphenol, ethyl p-hydroxybenzoate, propyl p-hydroxybenzoate, butyl p-hydroxybenzoate, benzyl p-hydroxybenzoate, p-hydroxybenzoate-p-chlorobenzyl, p-hydroxybenzoate-o-chlorobenzyl, p-hydroxybenzoate-p-methylbenzyl, p-hydroxybenzoate-n-octyl, benzoic acid, zinc salicylate, 1-hydroxy-2-naphthoic acid, 2-hydroxy-6-naphthoic acid, zinc 2-hydroxy-6-naphthoate, 4-hydroxydiphenylsulfone, 4-hydroxy-4' -chlorodiphenylsulfone, bis (4-hydroxyphenyl) sulfide, p-hydroxybenzoate, p-phenylbenzoic acid, p-hydroxybenzoate-n-octyl, p-phenylbenzoic acid, p-hydroxybenzoate-chlorobenzyl, p-hydroxybenzoate-, 2-hydroxy-p-methylbenzoic acid, zinc 3, 5-di-tert-butylsalicylate, tin 3, 5-di-tert-butylsalicylate, tartaric acid, oxalic acid, maleic acid, citric acid, succinic acid, stearic acid, 4-hydroxyphthalic acid, boric acid, thiourea derivatives, 4-hydroxythiophenol derivatives, bis (4-hydroxyphenyl) acetic acid, ethyl bis (4-hydroxyphenyl) acetate, n-propyl bis (4-hydroxyphenyl) acetate, m-butylbis (4-hydroxyphenyl) acetate, phenyl bis (4-hydroxyphenyl) acetate, benzyl bis (4-hydroxyphenyl) acetate, phenethyl bis (4-hydroxyphenyl) acetate, bis (3-methyl-4-hydroxyphenyl) acetic acid, methyl bis (3-methyl-4-hydroxyphenyl) acetate, N-propyl bis (3-methyl-4-hydroxyphenyl) acetate, 1, 7-bis (4-hydroxyphenylthio) 3, 5-dioxaheptane, 1, 5-bis (4-hydroxyphenylthio) 3-oxaheptane, dimethyl 4-hydroxyphthalite, 4-hydroxy-4 ' -methoxydiphenyl sulfone, 4-hydroxy-4 ' -ethoxydiphenyl sulfone, 4-hydroxy-4 ' -isopropoxydiphenyl sulfone, 4-hydroxy-4 ' -propoxydiphenyl sulfone, 4' -bis (3- (phenoxycarbonylamino) methylphenylureido) diphenyl sulfone, 4-hydroxy-4 ' -butoxydiphenyl sulfone, 4-hydroxy-4 ' -isobutoxydiphenyl sulfone, N-propylphenyl-1, N-propylphenyl-4-hydroxy-4-hydroxyphenylphenyl-4-phthalate, N-propylphenyl-4-hydroxy-4-hydroxyphenylphenyl-4, N-propylphenyl-, 4-hydroxy-4-butoxydiphenylsulfone, 4-hydroxy-4 ' -tert-butoxydiphenylsulfone, 4-hydroxy-4 ' -benzyloxydiphenylsulfone, 4-hydroxy-4 ' -phenoxydiphenylsulfone, 4-hydroxy-4 ' - (m-methylbenzyloxy) diphenylsulfone, 4-hydroxy-4 ' - (p-methylbenzyloxy) diphenylsulfone, 4-hydroxy-4 ' - (o-methylbenzyloxy) diphenylsulfone, 4-hydroxy-4 ' - (p-chlorobenzyloxy) diphenylsulfone, and N- (2- (3-phenylureido) phenyl) benzenesulfonamide. One of these color developers may be used alone, or two or more of these color developers may be used in combination.

The 50% cumulative volume particle diameter (D50) of the developer is preferably 0.1 micron or more but 0.5 micron or less, and more preferably 0.1 micron or more but 0.4 micron or less.

The method of measuring the 50% cumulative volume particle diameter (D50) of the color developer is not particularly limited and may be appropriately selected depending on the intended purpose. Examples of such methods include laser diffraction/scattering particle size distribution measuring instruments (instrument name: LA-920, available from Horiba, Ltd.).

The content of the color developer is not particularly limited, may be appropriately selected depending on the intended purpose, and is preferably 0.05 parts by mass or more but 10 parts by mass or less, and more preferably 1 part by mass or more but 5 parts by mass or less, with respect to 1 part by mass of the leuco dye.

Binder resin-

The binder resin is not particularly limited and may be appropriately selected depending on the intended purpose. Examples of the binder resin include: polyvinyl alcohol resins, starches or starch derivatives; cellulose derivatives such as hydroxymethyl cellulose, hydroxyethyl cellulose, carboxymethyl cellulose, methyl cellulose and ethyl cellulose; water-soluble polymers such as sodium polyacrylate, polyvinylpyrrolidone, acrylamide-acrylic acid ester copolymer, acrylamide-acrylic acid ester-methacrylic acid terpolymer, styrene-maleic anhydride copolymer alkali metal salt, isobutylene-maleic anhydride copolymer alkali metal salt, polyacrylamide, sodium alginate, gelatin and casein; for example, emulsions of polyvinyl acetate, polyurethane, polyacrylic acid, polyacrylate, vinyl chloride-vinyl acetate copolymer, polybutyl methacrylate, and ethylene-vinyl acetate copolymer; and, for example, latexes of styrene-butadiene copolymers and styrene-butadiene-acrylic acid copolymers. One of these binder resins may be used alone, or two or more of these binder resins may be used in combination. Among these binder resins, polyvinyl alcohol resins are preferred in terms of transparency and adhesion to the base material.

Other components-

The other components are not particularly limited and may be appropriately selected depending on the intended purpose. Examples of the other components include various hot melt substances as sensitivity improvers, auxiliary additives, surfactants, lubricants, load materials, ultraviolet absorbers, and coloring pigments.

Hot melt material

Examples of hot melt materials include: fatty acids such as stearic acid and behenic acid; fatty acid amides such as stearic acid amide and palmitic acid amide; fatty acid metal salts such as zinc stearate, aluminum stearate, calcium stearate, zinc palmitate, and zinc behenate; and p-benzylbiphenyl, terphenyl, triphenylmethane, benzyl p-benzyloxybenzoate, β -benzyloxynaphthalene, phenyl β -naphthoate, phenyl 1-hydroxy-2-naphthoate, methyl 1-hydroxy-2-naphthoate, diphenyl carbonate, ethylene carbonate, dibenzyl terephthalate, dimethyl terephthalate, 1, 4-dimethoxynaphthalene, 1, 4-diethoxynaphthalene, 1, 4-dibenzyloxynaphthalene, 1, 2-diphenoxyethane, 1, 2-bis (3-methylphenoxy) ethane, 1, 2-bis (4-methylphenoxy) ethane, 1, 4-diphenoxy-2-butene, 1, 2-bis (4-methoxyphenyloxy) ethane, dibenzoylmethane, 1, 4-diphenylcyclobutane, 1, 4-diphenylthio-2-butene, 1, 3-bis (2-vinyloxyethoxy) benzene, 1, 4-bis (2-vinyloxyethoxy) benzene, p- (2-vinyloxyethoxy) biphenyl, p-aryloxybiphenyl, p-propargyloxybiphenyl, dibenzoyloxymethane, dibenzoyloxypropane, dibenzyl disulfide, 1-diphenylethanol, 1-diphenylpropanol, p-benzylalcohol benzyloxy, 1, 3-phenoxy-2-propanol, N-octadecylcarbamoyl-p-methoxycarbonylbenzene, N-octadecylcarbamoylbenzene, 1, 2-bis (4-methoxyphenoxy) propane, 1, 5-bis (4-methoxyphenoxy) -3-oxapentane, dibenzyl ester oxalic acid, bis (4-methylbenzyl) oxalate and bis (4-chlorobenzyl) oxalate. One of these hot melt substances may be used alone, or two or more of these hot melt substances may be used in combination.

Auxiliary additives

The auxiliary additive is not particularly limited and may be appropriately selected depending on the intended purpose. Examples of the auxiliary additive include hindered phenol compounds and hindered amine compounds. One of these auxiliary additives may be used alone, or two or more of these auxiliary additives may be used in combination.

Examples of the auxiliary additive include 2,2 '-methylenebis (4-ethyl-6-tert-butylphenol), 4' -butylidenebis (6-tert-butyl-2-methylphenol), 1, 3-tris (2-methyl-4-hydroxy-5-tert-butylphenyl) butane, 1, 3-tris (2-methyl-4-hydroxy-5-cyclohexylphenyl) butane, 4 '-thiobis (6-tert-butyl-2-methylphenol), tetrabromobisphenol A, tetrabromobisphenol S, 4-thiobis (2-methylphenol), 4' -thiobis (2-chlorophenol), tetrakis (1,2,2,6, 6-pentamethyl-4-piperidyl) -1,2,3, 4-butane tetracarboxylic acid ester and tetrakis (1,2,2,6, 6-tetramethyl-4-piperidyl) -1,2,3, 4-butane tetracarboxylic acid ester. One of these auxiliary additives may be used alone, or two or more of these auxiliary additives may be used in combination.

Surfactants-

The surfactant is not particularly limited and may be appropriately selected depending on the intended purpose. Examples of the surfactant include anionic surfactants, nonionic surfactants, amphoteric surfactants, and fluorine-containing surfactants. One of these surfactants may be used alone, or two or more of these surfactants may be used in combination.

Examples of the anionic surfactant include polyoxyethylene alkyl ether acetate, dodecylbenzene sulfonate, laurate and polyoxyethylene alkyl ether sulfate. One of these anionic surfactants may be used alone, or two or more of these anionic surfactants may be used in combination.

Examples of the nonionic surfactant include acetylene glycol-based surfactants, polyoxyethylene alkyl ethers, polyoxyethylene alkylphenyl ethers, polyoxyethylene alkyl esters, and polyoxyethylene sorbitan fatty acid esters. One of these nonionic surfactants may be used alone, or two or more of these nonionic surfactants may be used in combination.

Examples of the acetylene glycol-based surfactant include 2,4,7, 9-tetramethyl-5-decyne-4, 7-diol, 3, 6-dimethyl-4-octyne-3, 6-diol, 3, 5-dimethyl-1-hexyne-3-diol, and 2,5,8, 11-tetramethyl-6-dodecyne-5, 8-diol. One of these acetylene glycol-based surfactants may be used alone, or two or more of these acetylene glycol-based surfactants may be used in combination.

Lubricants-

The lubricant is not particularly limited and may be appropriately selected depending on the intended purpose. Examples of the lubricant include higher fatty acids or metal salts of higher fatty acids, higher fatty acid amides, higher fatty acid esters, animal waxes, vegetable waxes, mineral waxes and petroleum waxes. One of these lubricants may be used alone, or two or more of these lubricants may be used in combination.

Supporting materials-

Examples of the supporting material include: inorganic powders such as calcium carbonate, silica, zinc oxide, titanium oxide, zirconium oxide, aluminum hydroxide, zinc hydroxide, barium sulfate, clay, kaolin, talc, surface-treated calcium and surface-treated silica; and organic powders such as urea-formaldehyde resins, styrene-methacrylic acid copolymers, polystyrene resins, and vinylidene chloride resins. One of these supporting materials may be used alone, or two or more of these supporting materials may be used in combination.

The content of the supporting material is not particularly limited and may be appropriately selected depending on the intended purpose, and is preferably 0.5 parts by mass or more but 5.0 parts by mass or less, and more preferably 1.0 parts by mass or more but 4.0 parts by mass or less, with respect to 1 part by mass of the binder resin.

UV absorbers

The ultraviolet absorber is not particularly limited and may be appropriately selected depending on the intended purpose. Examples of the ultraviolet absorber include a salicylic acid-based ultraviolet absorber, a benzophenone-based ultraviolet absorber, and a benzotriazole-based ultraviolet absorber.

Examples of the ultraviolet absorber include phenyl salicylate, p-tert-butylphenyl salicylate, p-octylphenyl salicylate, 2, 4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-octyloxybenzophenone, 2-hydroxy-4-dodecyloxybenzophenone, 2' -dihydroxy-4-methoxybenzophenone, 2' -dihydroxy-4, 4' -dimethoxybenzophenone, 2-hydroxy-4-methoxy-5-sulfobenzophenone, bis (2-methoxy-4-hydroxy-5-benzoylphenyl) methane, 2- (2' -hydroxy-5 ' -methylphenyl) benzotriazole, p-octylphenyl salicylate, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-dodecyloxybenzophenone, and the like, 2- (2 '-hydroxy-5' -tert-butylphenyl) benzotriazole, 2- (2 '-hydroxy-3', 5 '-di-tert-butylphenyl) chlorobenzotriazole, 2- (2' -hydroxy-3 '-tert-butyl-5' -methylphenyl) -5-chlorobenzotriazole, 2- (2 '-hydroxy-3', 5 '-di-tert-pentylphenyl) benzotriazole, 2- {2' -hydroxy-3 '- (3', 4',5', 6 '-tetrahydrophthalimidomethyl) -5' -methylphenyl } benzotriazole, benzotriazole derivatives, and mixtures thereof, 2,2' -methylenebis {4- (1,1,3, 3-tetramethylbutyl) -6- (2H-benzotriazol-2-yl) phenol }, 2- (2' -hydroxy-5 ' -methacryloxyphenyl) -2H-benzotriazole, 2- (3, 5-di-tert-amyl-2-hydroxyphenyl) benzotriazole, 2- (2' -hydroxy-5 ' -tert-octylphenyl) benzotriazole, and 2- (5-methyl-2-hydroxyphenyl) benzotriazole. One of these ultraviolet absorbers may be used alone, or two or more of these ultraviolet absorbers may be used in combination.

Coloring pigments

The coloring pigment is not particularly limited and may be appropriately selected depending on the intended purpose. Examples of the coloring pigment include chrome yellow, iron oxide pigment, molybdenum orange, cadmium red, zinc sulfide compound, hansa yellow, hansa orange, rose bengal, pyrazolone red, linoleic acid red, copper phthalocyanine blue, kopal polybrominated phthalocyanine blue (kopal polybromophthalocyanine blue), indanthrene blue, isodibenzanthracene violet, and anthrene orange (anthanthanthrene orange). One of these coloring pigments may be used alone, or two or more of these coloring pigments may be used in combination.

The method of forming the thermosensitive recording layer is not particularly limited and may be appropriately selected depending on the intended purpose. Examples of the method for forming the thermosensitive recording layer include the following methods: the leuco dye and the color developer are pulverized and dispersed together with the binder resin using a disperser such as a ball mill, an attritor, and a sand mill, the resultant is further mixed with, for example, other components as required to prepare a thermosensitive recording layer coating liquid, the thermosensitive recording layer coating liquid is coated on a transparent base material, and then the thermosensitive recording layer coating liquid is dried.

The coating method is not particularly limited and may be appropriately selected depending on the intended purpose. Examples of the coating method include a blade coating method, a gravure offset coating method, a bar coating method, a roll coating method, a knife coating method, an air knife coating method, a comma coating method (comma coating method), a U-comma coating method, an AKKU coating method, a smooth coating method, a micro-gravure coating method, a reverse roll coating method, a 4-roll or 5-roll coating method, a dip coating method, a curtain coating method, a slide coating method, and a die coating method.

50% cumulative volume particle diameter (D) of particles contained in the thermosensitive recording layer coating liquid₅₀) Preferably 0.10 micrometers or more but 3 micrometers or less, more preferably 0.10 micrometers or more but 0.50 micrometers or less, and particularly preferably 0.10 micrometers or more but 0.40 micrometers or less.

Examples of the particles contained in the thermosensitive recording layer coating liquid include dyes, developers, fillers, and coloring pigments.

The amount of the thermosensitive recording layer remaining adhered after drying is not particularly limited, may be appropriately selected depending on the intended purpose, and for example, is preferably 1.0g/m²Or greater but 20.0g/m²Or less, more preferably 2.0g/m²Or greater but 10.0g/m²Or less, particularly preferably 2.0g/m²Or greater but 4.0g/m²Or smaller.

< Barrier layer >

The barrier layer is a layer provided on a surface of the thermosensitive recording layer opposite to a surface of the thermosensitive recording layer facing the transparent base material. The barrier layer contains hollow particles and a binder resin, and further contains other components as necessary. By providing the barrier layer, degradation of the thermosensitive recording layer due to components contained in any other layer can be suppressed, and temporary fading resistance can be improved. Adhesion promoter migration from the adhesion promoter layer may also be prevented.

Hollow particles-

The hollow particles are particles filled with air or any other gas in a shell formed of a thermoplastic resin. Examples of the thermoplastic resin constituting the shell of the hollow particle include polystyrene resin, polyvinyl chloride resin, polyvinylidene chloride resin, polyvinyl acetate resin, polyacrylate resin, polyacrylonitrile resin, and polybutadiene resin or copolymers of these thermoplastic resins. Among these thermoplastic resins, particularly preferred are copolymers mainly formed of vinylidene chloride and acrylonitrile.

The hollow ratio of the hollow particles is preferably 45% or more, more preferably 80% or more. When the hollow ratio of the hollow particles is 45% or more, the color development sensitivity can be improved.

The hollow ratio refers to a ratio between the volume of the hollow particles and the hollow portion, and is expressed in percentage (%). The hollow particles can be considered to be almost spherical. Therefore, the hollow ratio is represented by the following formula.

The hollow ratio (%) ([ (volume of hollow portion)/(volume of hollow particle) ] × 100

The hollow particles preferably have a volume average particle diameter (outer particle diameter) of 0.4 μm or more but 10 μm or less. When the volume average particle diameter (outer particle diameter) of the hollow particles is 0.4 μm or more but 10 μm or less, the color development sensitivity can be improved.

The content of the hollow particles is preferably 35% by mass or more but 80% by mass or less with respect to the binder resin.

Binder resin-

The binder resin is not particularly limited and may be appropriately selected depending on the intended purpose. Examples of the binder resin include: polyvinyl alcohol resins, starches or starch derivatives; cellulose derivatives such as hydroxymethyl cellulose, hydroxyethyl cellulose, carboxymethyl cellulose, methyl cellulose and ethyl cellulose; water-soluble polymers such as sodium polyacrylate, polyvinylpyrrolidone, acrylamide-acrylic acid ester copolymer, acrylamide-acrylic acid ester-methacrylic acid terpolymer, styrene-maleic anhydride copolymer alkali metal salt, isobutylene-maleic anhydride copolymer alkali metal salt, polyacrylamide, sodium alginate, gelatin and casein; for example, emulsions of polyvinyl acetate, polyurethane, polyacrylic acid, polyacrylate, vinyl chloride-vinyl acetate copolymer, polybutyl methacrylate, and ethylene-vinyl acetate copolymer; and, for example, latexes (aqueous emulsions) of styrene-butadiene copolymers and styrene-butadiene-acrylic acid copolymers. One of these binder resins may be used alone, or two or more of these binder resins may be used in combination. Among these binder resins, a styrene-butadiene copolymer is preferably used in terms of adhesiveness to the thermosensitive recording layer and barrier function.

Other components-

The other components are not particularly limited and may be appropriately selected depending on the intended purpose. The same components as those suitable for the thermosensitive recording layer may be used.

The amount of the barrier layer remaining adhered after drying is not particularly limited, may be appropriately selected depending on the intended purpose, and is preferably 0.5g/m²Or greater but 10.0g/m²Or less, more preferably 1.0g/m²Or greater but 8.0g/m²Or less, and particularly preferably micro 3.0g/m²Or greater but 6.0g/m²Or smaller.

< other layer >

The other layers are not particularly limited and may be appropriately selected depending on the intended purpose. Examples of other layers include adhesion promoter layers.

Adhesion promoter layer

It is preferable to provide an adhesion promoter layer on the surface of the barrier layer opposite to the surface of the barrier layer on the thermosensitive recording layer side.

The tackifier that may be used in the tackifier layer is not particularly limited and may be appropriately selected depending on the intended purpose. Examples of tackifiers include pressure sensitive tackifiers and other types of tackifiers.

Examples of the tackifier include urea-formaldehyde resins, melamine resins, phenol resins, epoxy resins, vinyl acetate-based resins, vinyl acetate-acrylic-based copolymers, ethylene-vinyl acetate copolymers, acrylic-based resins, polyvinyl ether-based resins, vinyl chloride-vinyl acetate-based copolymers, polystyrene-based resins, polyester-based resins, polyurethane-based resins, polyamide-based resins, chlorinated polyolefin-based resins, polyvinyl butyral-based resins, acrylate-based copolymers, methacrylate-based copolymers, natural rubbers, cyanoacrylate-based resins, and silicone-based resins. One of these materials may be used alone, or two or more of these materials may be used in combination.

These materials may be crosslinked by a crosslinking agent. The material of the tackifier layer may be of a hot melt type.

The thickness of the tackifier layer is not particularly limited and may be appropriately selected depending on the intended purpose, and is preferably 0.1 micrometer or more or 20 micrometers or less.

The mode of the thermosensitive recording medium of the present disclosure is not particularly limited, and may be appropriately selected depending on the intended purpose. For example, the thermosensitive recording medium can be used as an adhesive type thermosensitive recording medium or a thermosensitive recording label by adhering a release paper to the tackifier layer.

The release paper is not particularly limited and may be appropriately selected depending on the intended purpose. Examples of the release paper include release paper obtained by pasting neutral paper, acid paper, or plastic. Further, a fixed-type illustration such as a color logo or a fixed phrase may be printed on the side of the transparent substrate opposite to the side on which the heat-sensitive recording layer is formed by a printing method such as ink-jet or offset printing.

The shape of the thermosensitive recording medium of the present disclosure is not particularly limited, and may be appropriately selected depending on the intended purpose. Examples of the shape of the thermosensitive recording medium include a label shape, a sheet shape, and a roll shape. Further, the thermosensitive recording medium may be a substrate-less type wound in a roll shape with a release layer formed on a transparent base material.

Fig. 1 is a view showing an example of a thermosensitive recording medium of the present disclosure. As shown in fig. 1, the thermosensitive recording medium 1 of the present disclosure includes a thermosensitive recording layer 12 and a barrier layer 13 in this order on a transparent base material 11. When thermal energy is applied to the thermosensitive recording layer 12 from the surface of the thermosensitive recording medium 1 of the present disclosure having the transparent base material 11 by the heat source 21, the thermosensitive recording layer 12 develops color. As shown in fig. 2, an adhesion promoter layer 14 may be provided on the barrier layer 13. Further, as shown in fig. 3, a release paper 15 may be provided on the tackifier layer 14. Further, as shown in fig. 4, a layer configuration in which a peeling layer 16 is provided on a transparent base material 11 may be employed.

(method for producing thermosensitive recording Medium)

The method for producing a thermosensitive recording medium of the present disclosure includes a step of forming a thermosensitive recording layer on a transparent base material and a step of forming a barrier layer containing hollow particles and a binder resin on the thermosensitive recording layer, and further includes other steps as needed.

< step of Forming thermosensitive recording layer >

The step of forming the thermosensitive recording layer is not particularly limited and may be appropriately selected depending on the intended purpose. The same steps as those of the above-described method for forming a thermosensitive recording layer may be employed.

Before the thermosensitive recording layer coating liquid is applied on the surface, the surface of the transparent base material to be provided with the thermosensitive recording layer is preferably subjected to surface reforming by, for example, corona discharge treatment, oxidation reaction treatment (e.g., chromic acid), etching treatment, treatment for imparting easy tackiness, and antistatic treatment. This makes it possible to improve the adhesion between the transparent base material and the thermosensitive recording layer. In addition to these surface reforming methods, a layer containing, for example, a styrene-butadiene polymer (an easy-adhesion layer) may be formed on a transparent base material, and then a thermosensitive recording layer may be formed on the layer containing the styrene-butadiene polymer. This makes it possible to prevent peeling of the film.

< step of Forming Barrier layer >

Next, a barrier layer coating liquid is coated on the thermosensitive recording layer to form a barrier layer. The step of forming the barrier layer is not particularly limited and may be appropriately selected depending on the intended purpose. Examples of this step include the following steps: the hollow particles are dispersed together with an aqueous solution containing a binder resin using a disperser to prepare a barrier layer coating liquid, other materials are added to the resultant as needed, the barrier layer coating liquid is applied to the thermosensitive recording layer, and then the barrier layer coating liquid is dried.

The method of coating the barrier layer coating liquid is not particularly limited and may be appropriately selected depending on the intended purpose. For example, the same method as the above-described method for coating a thermosensitive recording layer coating liquid may be employed.

< step of Forming adhesion promoter layer >

Whether to form an adhesion promoter layer on the barrier layer is optional. In the case of forming the tackifier layer, the tackifier layer may be formed by coating the tackifier on the barrier layer by a coating method such as a bar coating method, a roll coating method, a comma coating method, and a gravure coating method and then drying the tackifier.

< other steps >

As another step, for example, in the case of producing a sticking type thermosensitive recording medium, it is preferable to stick a release paper on the tackifier layer. The method of attaching the release paper is not particularly limited, and a method for general purpose may be used.

In the case of producing a substrate-less type thermosensitive recording medium, the release layer coating liquid may be coated on the side of the transparent base material opposite to the side where the thermosensitive recording layer is formed. As a method for applying the release layer coating liquid, the same method as the above-described method for applying the thermosensitive recording layer coating liquid can be used.

Heat in the present disclosureA method of recording information on the thermosensitive recording medium is not particularly limited and may be appropriately selected according to the intended purpose, so long as the method can apply light or thermal energy to the thermosensitive recording layer through the surface of the thermosensitive recording layer having the transparent base material using a heat source. Examples of heat sources include thermal head, thermal stamp, CO₂Lasers and semiconductor lasers.

Examples of the use of the thermosensitive recording medium of the present disclosure include use by pasting or attaching on an article such as a solvent container which is required to have high solvent resistance. The material of the solvent container is not particularly limited, and examples of the material of the solvent container include metal, plastic, and glass. Using a thermosensitive recording medium on an article required to have high solvent resistance, even if a solvent adheres to the thermosensitive recording medium, the article can be appropriately managed without occurrence of, for example, fading of characters.

(products of manufacture)

The article of the present disclosure includes the thermosensitive recording medium of the present disclosure.

As the thermosensitive recording medium, the thermosensitive recording medium of the present disclosure may be suitably used.

The state in which the article includes the thermosensitive recording medium of the present disclosure means a state in which the thermosensitive recording medium of the present disclosure is, for example, stuck or attached to the article.

The article of the present disclosure is not particularly limited, and may be appropriately selected depending on the intended purpose, as long as the article includes the thermosensitive recording medium of the present disclosure. Examples of articles include packaging materials, and wrapping paper. Examples of articles to be specifically mentioned include articles requiring high solvent resistance.