Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41M—PRINTING, DUPLICATING, MARKING, OR COPYING PROCESSES; COLOUR PRINTING
  • B41M5/00—Duplicating or marking methods; Sheet materials for use therein
  • B41M5/26—Thermography ; Marking by high energetic means, e.g. laser otherwise than by burning, and characterised by the material used
  • B41M5/30—Thermography ; Marking by high energetic means, e.g. laser otherwise than by burning, and characterised by the material used using chemical colour formers
  • B41M5/333—Colour developing components therefor, e.g. acidic compounds
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41M—PRINTING, DUPLICATING, MARKING, OR COPYING PROCESSES; COLOUR PRINTING
  • B41M5/00—Duplicating or marking methods; Sheet materials for use therein
  • B41M5/26—Thermography ; Marking by high energetic means, e.g. laser otherwise than by burning, and characterised by the material used
  • B41M5/30—Thermography ; Marking by high energetic means, e.g. laser otherwise than by burning, and characterised by the material used using chemical colour formers
  • B41M5/323—Organic colour formers, e.g. leuco dyes
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41M—PRINTING, DUPLICATING, MARKING, OR COPYING PROCESSES; COLOUR PRINTING
  • B41M5/00—Duplicating or marking methods; Sheet materials for use therein
  • B41M5/26—Thermography ; Marking by high energetic means, e.g. laser otherwise than by burning, and characterised by the material used
  • B41M5/40—Thermography ; Marking by high energetic means, e.g. laser otherwise than by burning, and characterised by the material used characterised by the base backcoat, intermediate, or covering layers, e.g. for thermal transfer dye-donor or dye-receiver sheets; Heat, radiation filtering or absorbing means or layers; combined with other image registration layers or compositions; Special originals for reproduction by thermography
  • B41M5/42—Intermediate, backcoat, or covering layers
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41M—PRINTING, DUPLICATING, MARKING, OR COPYING PROCESSES; COLOUR PRINTING
  • B41M5/00—Duplicating or marking methods; Sheet materials for use therein
  • B41M5/26—Thermography ; Marking by high energetic means, e.g. laser otherwise than by burning, and characterised by the material used
  • B41M5/40—Thermography ; Marking by high energetic means, e.g. laser otherwise than by burning, and characterised by the material used characterised by the base backcoat, intermediate, or covering layers, e.g. for thermal transfer dye-donor or dye-receiver sheets; Heat, radiation filtering or absorbing means or layers; combined with other image registration layers or compositions; Special originals for reproduction by thermography
  • B41M5/42—Intermediate, backcoat, or covering layers
  • B41M5/44—Intermediate, backcoat, or covering layers characterised by the macromolecular compounds
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41M—PRINTING, DUPLICATING, MARKING, OR COPYING PROCESSES; COLOUR PRINTING
  • B41M2205/00—Printing methods or features related to printing methods; Location or type of the layers
  • B41M2205/04—Direct thermal recording [DTR]
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41M—PRINTING, DUPLICATING, MARKING, OR COPYING PROCESSES; COLOUR PRINTING
  • B41M2205/00—Printing methods or features related to printing methods; Location or type of the layers
  • B41M2205/38—Intermediate layers; Layers between substrate and imaging layer
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41M—PRINTING, DUPLICATING, MARKING, OR COPYING PROCESSES; COLOUR PRINTING
  • B41M5/00—Duplicating or marking methods; Sheet materials for use therein
  • B41M5/26—Thermography ; Marking by high energetic means, e.g. laser otherwise than by burning, and characterised by the material used
  • B41M5/40—Thermography ; Marking by high energetic means, e.g. laser otherwise than by burning, and characterised by the material used characterised by the base backcoat, intermediate, or covering layers, e.g. for thermal transfer dye-donor or dye-receiver sheets; Heat, radiation filtering or absorbing means or layers; combined with other image registration layers or compositions; Special originals for reproduction by thermography
  • B41M5/42—Intermediate, backcoat, or covering layers
  • B41M5/426—Intermediate, backcoat, or covering layers characterised by inorganic compounds, e.g. metals, metal salts, metal complexes

Definitions

• the present invention relates to a heat-sensitive recording material utilizing a color-forming reaction between a leuco dye and a color former.
• thermosensitive recording medium having high sensitivity, high whiteness, and high print pixel reproducibility
• an intermediate layer containing an inorganic or organic pigment is provided between a support and a thermosensitive recording layer.
• a latex having a property of gelling at a certain temperature temperature-sensitive gelling property
• Patent Document 1 a latex having a property of gelling at a certain temperature (temperature-sensitive gelling property) as a binder of an intermediate layer.
• An object of the present invention is to provide a thermosensitive recording medium having high image quality and excellent halftone print density.
• the present inventors have conducted intensive studies to solve the above-mentioned object, and as a result, with respect to an undercoat layer containing hollow particles having a high hollow ratio, utilizing a crosslinking reaction of a polyvinyl alcohol-based resin before drying the undercoat layer.
• the coating solution By gelling the coating solution and suppressing the movement of the hollow particles having a high hollow ratio with a large buoyancy to the surface layer, the hollow particles are uniformly distributed in the undercoat layer, and the smoothness is improved.
• the inventors have found that the problem is solved, and have completed the present invention. That is, the present invention relates to the following thermosensitive recording medium.
• Item 1 a thermosensitive recording medium having, on a support, an intermediate layer, an undercoat layer containing hollow particles and a polyvinyl alcohol-based resin, and a thermosensitive recording layer containing a leuco dye and a coloring agent in this order,
• the intermediate layer contains a crosslinking agent capable of crosslinking the polyvinyl alcohol-based resin
• a thermosensitive recording medium wherein the hollow particles have a hollow ratio of 60% or more.
• Item 2 The heat-sensitive recording material according to Item 1, wherein the crosslinking agent contains a boron compound.
• Item 3 The heat-sensitive recording material according to Item 1, wherein the crosslinking agent contains at least one selected from the group consisting of zirconium nitrate, zirconium chloride, and zirconium hydroxychloride.
• Item 4 The heat-sensitive recording material according to any one of Items 1 to 3, wherein the hollow particles have a hollow ratio of 70% or more.
• Item 5 The heat-sensitive recording material according to any one of Items 1 to 4, wherein the polyvinyl alcohol-based resin is crosslinked.
• thermosensitive recording medium including the following steps (A) to (C): (A) a step of applying a coating solution containing a crosslinking agent capable of crosslinking a polyvinyl alcohol-based resin on a support; (B) a step of applying and drying an undercoat layer coating liquid containing hollow particles having a hollow ratio of 60% or more and a polyvinyl alcohol-based resin on the coating liquid applied in step (A), and (C) A step of coating and drying a thermosensitive recording layer coating solution containing a leuco dye and a color former on the undercoat layer.
• Item 7 A method for producing a thermosensitive recording medium including the following steps (a) and (b): (A) a step of applying a coating solution containing a crosslinking agent capable of crosslinking a polyvinyl alcohol-based resin on a support; and (b) a coating solution having a hollow ratio on the coating solution applied in step (a). A step of simultaneously applying and drying a coating liquid for an undercoat layer containing 60% or more of hollow particles and a polyvinyl alcohol-based resin, and a coating liquid for a thermosensitive recording layer containing a leuco dye and a color former.
• Item 8 The production method according to Item 6, wherein the undercoat layer coating liquid is applied by a curtain coating method.
• the thermal recording medium of the present invention has high image quality and excellent halftone print density.
• the expression “comprising” includes the concepts of “comprising”, “consisting only of substance”, and “consisting of only”.
• the “average particle diameter” refers to a volume-based median diameter measured by a laser diffraction method. More simply, the particle diameter may be measured from a particle image (SEM image) using an electron microscope, and may be indicated by an average value of 10 particles.
• the present invention is a heat-sensitive recording material having, in this order, an intermediate layer, an undercoat layer containing hollow particles and a polyvinyl alcohol-based resin, and a heat-sensitive recording layer containing a leuco dye and a color former on a support.
• the intermediate layer contains a crosslinking agent capable of crosslinking the polyvinyl alcohol-based resin
• the hollow particles have a hollow ratio of 60% or more.
• the support in the present invention is not particularly limited in type, shape, dimensions, and the like, and includes, for example, high-quality paper (acidic paper, neutral paper), medium-quality paper, coated paper, art paper, cast-coated paper, glassine paper, In addition to resin-laminated paper, polyolefin-based synthetic paper, synthetic fiber paper, non-woven fabric, synthetic resin film, etc., it can be appropriately selected from various transparent supports and used.
• the thickness of the support is not particularly limited, and is usually about 20 to 200 ⁇ m.
• the density of the support is not particularly limited, and is preferably about 0.60 to 0.85 g / cm 3 .
• the thermosensitive recording medium of the present invention has an intermediate layer containing a crosslinking agent capable of crosslinking the polyvinyl alcohol-based resin between the support and the undercoat layer.
• a crosslinking agent capable of crosslinking the polyvinyl alcohol-based resin between the support and the undercoat layer.
• crosslinking agent examples include aldehyde compounds such as glyoxal, polyamine compounds such as polyethyleneimine, epoxy compounds, polyamide resins, melamine resins, glyoxylates, dimethylolurea compounds, aziridine compounds, and blocked isocyanate compounds; ammonium persulfate.
• aldehyde compounds such as glyoxal
• polyamine compounds such as polyethyleneimine, epoxy compounds, polyamide resins, melamine resins, glyoxylates, dimethylolurea compounds, aziridine compounds, and blocked isocyanate compounds
• ammonium persulfate examples include aldehyde compounds such as glyoxal, polyamine compounds such as polyethyleneimine, epoxy compounds, polyamide resins, melamine resins, glyoxylates, dimethylolurea compounds, aziridine compounds, and blocked isocyanate compounds; ammonium persulfate.
• inorganic compounds such as ferric chloride, magnesium chloride, sodium tetraborate and potassium tetraborate; boron compounds such as borax, boric acid, boric acid triester, and boron-based polymers; zirconium compounds such as zirconium nitrate, zirconium chloride and zirconium hydroxychloride Hydrazide compounds, glyoxylates, and the like.
• boron compound, zirconium nitrate, zirconium chloride, and zirconium hydroxychloride may be used alone or in combination of two or more.
• the amount of the crosslinking agent to be used is preferably in the range of about 2.0 to 15.0 parts by mass based on 100 parts by mass of the total solids of the polyvinyl alcohol resin.
• the intermediate layer is generally formed by applying a coating liquid for an intermediate layer prepared by mixing and stirring a cross-linking agent or the like with water as a medium, on a support.
• the coating amount of the intermediate layer coating solution is not particularly limited, is preferably about 0.05 ⁇ 2.0g / m 2 by dry weight, more preferably about 0.1 ⁇ 1.0g / m 2.
• the thermal recording medium of the present invention has an undercoat layer containing hollow particles having a hollow ratio of 60% or more and a polyvinyl alcohol resin between the intermediate layer and the thermal recording layer.
• the recording sensitivity can be increased.
• the cushioning property is improved by the presence of the hollow particles, the printed image becomes clearer and the halftone print density can be increased.
• the hollow particles include plastic hollow particles.
• plastic hollow particles conventionally known ones, for example, a polymer having a crosslinked structure in a film material, for example, an acrylic resin (for example, an acrylic resin containing acrylonitrile as a component), a styrene resin, a vinylidene chloride resin And the like.
• the hollow ratio of the hollow particles is preferably at least 65%, more preferably at least 70%.
• the hollow ratio of the hollow particles is obtained by measuring the true specific gravity by the IPA method and calculating the true specific gravity from the value as follows.
• Pretreatment of the sample The sample is dried at 60 ° C all day and night to obtain a sample.
• Reagent / isopropyl alcohol (IPA: first-class reagent) (3) Measuring method-The measuring flask is precisely weighed (W1). -About 0.5 g of the dried sample is placed in a measuring flask and precisely weighed (W2). Add about 50 mg of IPA and shake thoroughly to completely remove air outside the capsule. ⁇ Add IPA up to the marked line and evaluate it (W3).
• the hollow ratio is a value obtained also by the following equation (d 3 / D 3 ) ⁇ 100.
• d indicates the inner diameter of the hollow plastic particles
• D indicates the outer diameter of the hollow plastic particles.
• the average particle diameter of the hollow plastic particles is preferably about 0.5 to 10 ⁇ m.
• the content ratio of the plastic hollow particles can be selected from a wide range, and is generally preferably about 2 to 90% by mass, more preferably about 5 to 70% by mass, based on the total solid content of the undercoat layer.
• the undercoat layer may contain oil-absorbing pigments having an oil absorption of 70 ml / 100 g or more, especially about 80 to 150 ml / 100 g, and / or heat-expandable particles.
• oil-absorbing pigments having an oil absorption of 70 ml / 100 g or more, especially about 80 to 150 ml / 100 g, and / or heat-expandable particles.
• the oil absorption is a value determined according to the method described in JIS K5101.
• oil absorbing pigments can be used, and specific examples include calcined kaolin, amorphous silica, light calcium carbonate, and inorganic pigments such as talc.
• the average particle size of the primary particles of these oil-absorbing pigments is preferably about 0.01 to 5 ⁇ m, particularly preferably about 0.02 to 3 ⁇ m.
• the content ratio of the oil-absorbing pigment can be selected from a wide range, it is generally preferably about 2 to 95% by mass, more preferably about 5 to 90% by mass of the total solid content of the undercoat layer.
• the undercoat layer is generally formed by mixing and stirring plastic hollow particles, an oil-absorbing pigment, an adhesive, an auxiliary agent, and the like with water as a medium, and applying and drying a coating liquid for an undercoat layer on a support.
• the coating amount of the undercoat layer coating liquid is not particularly limited, is preferably about 3 ⁇ 20g / m 2 by dry weight, more preferably about 5 ⁇ 12g / m 2.
• Polyvinyl alcohol resin is used as an adhesive.
• examples of the polyvinyl alcohol-based resin include polyvinyl alcohol, completely saponified polyvinyl alcohol, partially saponified polyvinyl alcohol, diacetone-modified polyvinyl alcohol, acetoacetyl-modified polyvinyl alcohol, carboxy-modified polyvinyl alcohol, and silicon-modified polyvinyl alcohol.
• the polyvinyl alcohol-based resin exists in a state cross-linked by a cross-linking reaction with a cross-linking agent included in the intermediate layer.
• the content ratio of the polyvinyl alcohol-based resin can be selected in a wide range, it is generally preferably about 0.5 to 20% by mass, more preferably about 1.0 to 15% by mass, based on the total solid content of the undercoat layer.
• a polyvinyl alcohol-based resin is used as an adhesive in the undercoat layer.
• various known adhesives can be used in combination as long as there is no problem as needed.
• Such an adhesive can be appropriately selected from those that can be used for the heat-sensitive recording layer.
• oxidized starch, starch-vinyl acetate graft copolymer, styrene-butadiene-based latex and the like are preferable.
• the heat-sensitive recording layer of the heat-sensitive recording medium of the present invention may contain various known colorless or light-colored leuco dyes. Specific examples of such a leuco dye are shown below.
• leuco dyes include, for example, 3,3-bis (p-dimethylaminophenyl) -6-dimethylaminophthalide, 3- (4-diethylamino-2-methylphenyl) -3- (4-dimethylamino Blue-forming dyes such as phenyl) -6-dimethylaminophthalide and fluoran, 3- (N-ethyl-Np-tolyl) amino-7-N-methylanilinofluoran, 3-diethylamino-7-ani Green coloring dyes such as linofluoran, 3-diethylamino-7-dibenzylaminofluoran, rhodamine B-anilinolactam, 3,6-bis (diethylamino) fluoran- ⁇ -anilinolactam, 3-cyclohexylamino- 6-chlorofluorane, 3-diethylamino-6-methyl-7-chlorofluorane, 3-dieththy
• the content ratio of the leuco dye is not particularly limited, and is preferably about 3 to 30% by mass, more preferably about 5 to 25% by mass, and still more preferably about 7 to 20% by mass based on the total solid content of the heat-sensitive recording layer. .
• the content is 3% by mass or more, the coloring ability can be enhanced, and the printing density can be improved.
• heat resistance can be improved.
• the coloring agent include, for example, 4-tert-butylphenol, 4-acetylphenol, 4-tert-octylphenol, 4,4′-sec-butylidenediphenol, 4-phenylphenol, 4,4′-dihydroxy Diphenylmethane, 4,4'-isopropylidenediphenol, 4,4'-cyclohexylidenediphenyl, 4,4'-cyclohexylidenediphenol, 1,1-bis (4-hydroxyphenyl) -ethane, 1,1- Bis (4-hydroxyphenyl) -1-phenylethane, 4,4′-bis (p-tolylsulfonylaminocarbonylamino) diphenylmethane, 1,1-bis (4-hydroxyphenyl) cyclohexane, 2,2′-bis [ 4- (4-hydroxyphenyl) phenoxy] diethyl ether, 4,4′- Hydroxydiphenyl sulfide, 4,4'-thiobis (3-methyl)
• coloring agent further include 4,4′-bis [(4-methyl-3-phenoxycarbonylaminophenyl) ureido] diphenyl sulfone represented by the following general formula (1) and 4,4′-bis [( 2-methyl-5-phenoxycarbonylaminophenyl) ureido] diphenylsulfone, 4- (2-methyl-3-phenoxycarbonylaminophenyl) ureido-4 '-(4-methyl-5-phenoxycarbonylaminophenyl) ureidodiphenylsulfone And the like, a diphenylsulfone derivative represented by the following general formula (2), and the like.
• n an integer of 1 to 6.
• the color former is not limited to these, and two or more compounds can be used in combination as needed.
• the content of the color former is not particularly limited and may be adjusted according to the leuco dye to be used.
• the amount is preferably 0.5 part by mass or more, more preferably 0.8 part by mass, per 1 part by mass of the leuco dye.
• the above is more preferable, 1 part by mass or more is further preferable, 1.2 parts by mass or more is still more preferable, and 1.5 parts by mass or more is particularly preferable.
• the content of the colorant is preferably 10 parts by mass or less, more preferably 5 parts by mass or less, still more preferably 4 parts by mass or less, particularly preferably 3.5 parts by mass or less, based on 1 part by mass of the leuco dye. .
• the content is 0.5 parts by mass or more, recording performance can be improved.
• the content is 10 parts by mass or less, background fog in a high-temperature environment can be effectively suppressed.
• a storability improver can be further contained in the heat-sensitive recording layer, mainly in order to further improve the storability of the color image.
• a preservative improver include 1,1,3-tris (2-methyl-4-hydroxy-5-cyclohexylphenyl) butane, 1,1,3-tris (2-methyl-4-hydroxy -5-tert-butylphenyl) butane, 1,1-bis (2-methyl-4-hydroxy-5-tert-butylphenyl) butane, 4,4 '-[1,4-phenylenebis (1-methylethylidene) )] Phenol compounds such as bisphenol and 4,4 ′-[1,3-phenylenebis (1-methylethylidene)] bisphenol; 4-benzyloxyphenyl-4 ′-(2-methyl-2,3-epoxypropyloxy ) Phenylsulfone, 4- (2-methyl-1,2-epoxyethyl) diphen
• a preservability improver When a preservability improver is used, its use amount may be an effective amount for preservability improvement. Usually, it is preferably about 1 to 30% by mass based on the total solid content of the heat-sensitive recording layer. It is more preferably about 20% by mass.
• a sensitizer may be contained in the heat-sensitive recording layer of the invention. Thereby, the recording sensitivity can be increased.
• the sensitizer include stearic acid amide, methoxycarbonyl-N-stearic acid benzamylide, N-benzoylstearic acid amide, N-eicosanoic acid amide, ethylenebisstearic acid amide, behenic acid amide, methylenebisstearic acid amide, N-methylol stearamide, dibenzyl terephthalate, dimethyl terephthalate, dioctyl terephthalate, diphenyl sulfone, benzyl p-benzyloxybenzoate, phenyl 1-hydroxy-2-naphthoate, phenyl 2-naphthyl benzyl ether, m-terphenyl , P-benzylbiphenyl, di-p-chlorobenzyl oxalate,
• the content ratio of the sensitizer may be an amount effective for sensitization, and is usually preferably about 2 to 40% by mass, more preferably about 5 to 25% by mass based on the total solids of the heat-sensitive recording layer. preferable.
• a fine pigment having a high whiteness and an average particle diameter of 10 ⁇ m or less can be contained in the heat-sensitive recording layer.
• inorganic pigments such as calcium carbonate, magnesium carbonate, kaolin, clay, talc, calcined clay, silica, diatomaceous earth, synthetic aluminum silicate, zinc oxide, titanium oxide, aluminum hydroxide, barium sulfate, surface-treated calcium carbonate, and silica
• organic pigments such as urea-formalin resin, styrene-methacrylic acid copolymer resin, and polystyrene resin.
• the content of the pigment is preferably an amount that does not lower the color density, that is, 50% by mass or less based on the total solid content of the thermosensitive coloring layer.
• An adhesive is used as another component material constituting the heat-sensitive recording layer, and a cross-linking agent, a wax, a metal soap, a water-proofing agent, a dispersant, a colored dye, a fluorescent dye, and the like can be used as necessary.
• Examples of the adhesive used for the coating solution for the heat-sensitive recording layer include a water-soluble adhesive and a water-dispersible adhesive.
• Examples of the water-soluble adhesive include polyvinyl alcohol, carboxy-modified polyvinyl alcohol, acetoacetyl-modified polyvinyl alcohol, diacetone-modified polyvinyl alcohol, modified polyvinyl alcohol such as silicon-modified polyvinyl alcohol, starch and derivatives thereof, methoxycellulose, carboxymethylcellulose, and hydroxy.
• Cellulose derivatives such as methylcellulose, hydroxyethylcellulose, hydroxypropylmethylcellulose, methylcellulose, and ethylcellulose, sodium polyacrylate, polyvinylpyrrolidone, polyamide, diisobutylene-maleic anhydride copolymer salt, styrene-acrylic acid copolymer salt, styrene- Maleic anhydride copolymer salt, ethylene-maleic anhydride copolymer salt, acrylamide-ac Le ester copolymers, acrylic acid amide - acrylic acid ester - methacrylic acid copolymer, polyacrylamide, sodium alginate, gelatin, casein, gum arabic, and the like.
• water-dispersible adhesive examples include polyvinyl acetate, polyurethane, styrene-butadiene copolymer, styrene-butadiene-acrylonitrile copolymer, acrylonitrile-butadiene copolymer, polyacrylic acid, polyacrylate, vinyl chloride-acetic acid.
• Water such as vinyl copolymer, polybutyl methacrylate, ethylene-vinyl acetate copolymer, silylated urethane, acryl-silicon complex, and acryl-silicon-urethane complex, urea resin, melamine resin, amide resin, polyurethane resin, etc.
• examples include latexes of insoluble polymers. These can be used alone or in combination of two or more. At least one of these is blended in an amount of preferably about 5 to 50% by mass, more preferably about 10 to 40% by mass, based on the total solid content of the heat-sensitive recording layer.
• a crosslinking agent for curing the adhesive of the heat-sensitive recording layer or other layers can be contained in the heat-sensitive recording layer.
• the crosslinking agent include aldehyde compounds such as glyoxal, polyamine compounds such as polyethyleneimine, epoxy compounds, polyamide resins, melamine resins, glyoxylates, dimethylolurea compounds, aziridine compounds, and blocked isocyanate compounds; ammonium persulfate.
• inorganic compounds such as ferric chloride, magnesium chloride, sodium tetraborate and potassium tetraborate; boric acid, boric acid triesters, boron-based polymers, hydrazide compounds, and glyoxylates. These may be used alone or in combination of two or more.
• the amount of the crosslinking agent used is preferably in the range of about 1 to 10 parts by mass with respect to 100 parts by mass of the total solid content of the heat-sensitive recording layer. Thereby, the water resistance of the heat-sensitive recording layer can be improved.
• waxes such as paraffin wax, carnauba wax, microcrystalline wax, polyolefin wax, and polyethylene wax; for example, higher fatty acid amides such as stearamide, ethylenebisstearic acid amide, higher fatty acid esters, and derivatives thereof. Can be mentioned.
• metal soaps include higher fatty acid polyvalent metal salts such as zinc stearate, aluminum stearate, calcium stearate, and zinc oleate. If necessary, various auxiliaries such as an oil repellent, a defoaming agent, and a viscosity modifier can be added to the heat-sensitive recording layer as long as the effects of the present invention are not impaired.
• the heat-sensitive recording layer is generally formed by using water as a dispersion medium, a leuco dye and a color former, and if necessary, a sensitizer and a preservability improver together or separately, such as a ball mill, a co-ball mill, an attritor, and a vertical and horizontal sand mill. And a water-soluble synthetic polymer compound such as polyacrylamide, polyvinylpyrrolidone, polyvinyl alcohol, methylcellulose, styrene-maleic anhydride copolymer salt, and other surfactants.
• a water-soluble synthetic polymer compound such as polyacrylamide, polyvinylpyrrolidone, polyvinyl alcohol, methylcellulose, styrene-maleic anhydride copolymer salt, and other surfactants.
• a coating liquid for a heat-sensitive recording layer prepared by mixing a pigment, an adhesive, an auxiliary agent, and the like as necessary is applied. After that, it is dried and formed on the undercoat layer.
• the coating amount of the heat-sensitive recording layer is not particularly limited, is preferably about 1 ⁇ 12g / m 2 of the coating amount after drying, more preferably 2 ⁇ 10g / m 2, more preferably 2.5 ⁇ 8g / m 2 And 3 to 5.5 g / m 2 are particularly preferred.
• the heat-sensitive recording layer can be formed in two or more layers as necessary, and the composition and the coating amount of each layer may be the same or different.
• a protective layer may be provided on the heat-sensitive recording layer as needed.
• the protective layer preferably contains a pigment and an adhesive.
• the protective layer preferably contains a lubricant such as polyolefin wax and zinc stearate for the purpose of preventing sticking to the thermal head, and may also contain an ultraviolet absorber. Further, by providing a glossy protective layer, it is possible to increase the added value of the product.
• the adhesive contained in the protective layer is not particularly limited, and any of a water-soluble adhesive and a water-dispersible adhesive can be used.
• the adhesive can be appropriately selected from those that can be used for the heat-sensitive recording layer.
• the protective layer is generally formed on the heat-sensitive recording layer by applying a protective layer coating solution prepared by mixing water, a dispersion medium, a pigment, an adhesive, and, if necessary, an auxiliary agent, and then drying. Is done.
• the coating amount of the protective layer coating solution is not particularly limited, and is preferably about 0.3 to 15 g / m 2 , more preferably about 0.3 to 10 g / m 2 , and 0.5 to 8 g / m 2 in terms of dry weight. About 2 is more preferred, about 1 to 8 g / m 2 is particularly preferred, and about 1 to 5 g / m 2 is even more preferred.
• the protective layer can be formed in two or more layers as necessary, and the composition and the coating amount of each layer may be the same or different.
• the heat-sensitive recording material in order to increase the added value of the heat-sensitive recording material, can be further processed to obtain a heat-sensitive recording material having higher functions.
• an adhesive paper, a rewet adhesive paper, a delayed tack paper, or the like can be obtained by applying a coating process using an adhesive, a rewet adhesive, a delayed tack type adhesive, or the like to the back surface.
• functions such as thermal transfer paper, ink jet recording paper, carbonless paper, electrostatic recording paper, and zeographic paper can be imparted to the recording paper so that double-sided recording is possible.
• a double-sided thermal recording medium can also be used.
• a back layer may be provided for suppressing penetration of oil and plasticizer from the back surface of the thermosensitive recording medium, and for controlling curl and preventing static charge.
• Examples of the method for forming each of the above layers on the support include an air knife method, a blade method, a gravure method, a roll coater method, a spray method, a dip method, a bar method, a curtain method, a slot die method, a slide die method, and an extrusion method. Any of the known coating methods may be used. Each coating solution may be applied and dried one layer at a time to form each layer, or the same coating solution may be applied in two or more layers. Further, simultaneous multi-layer coating in which two or more layers are simultaneously coated may be performed. In addition, after any layers have been formed or after all layers have been formed, a smoothing process can be performed using a known method such as a super calender or a soft calender.
• the undercoat layer is preferably a layer formed by a curtain coating method.
• a layer having a uniform thickness can be formed, and the recording sensitivity can be increased, and the barrier properties against oil, plasticizer, alcohol, and the like can be increased.
• the curtain coating method is a method in which a coating liquid flows down and falls freely and is applied to the intermediate layer in a non-contact manner, and a known method such as a slide curtain method, a couple curtain method, or a twin curtain method can be used. There is no restriction.
• Example 1 Preparation of coating liquid for intermediate layer Borax was dissolved in water to obtain a coating liquid for an intermediate layer having a concentration of 0.5%.
• coating liquid for undercoat layer 412 parts of hollow particles A (trade name: A-170, manufactured by Sansui Co., solid content concentration: 17.0%, hollow ratio: 72%), styrene / butadiene latex (trade name: L) -1571, 52 parts by Asahi Kasei Chemicals Corporation, solid content concentration 48%), 10 parts of a 10% aqueous solution of polyvinyl alcohol (degree of polymerization 1700, degree of saponification 88%), and carboxymethyl cellulose (trade name: Cellogen 7A, Daiichi Kogyo Seiyaku Co., Ltd.) And 2.5 parts of a composition prepared by mixing and stirring to obtain a coating liquid for an undercoat layer.
• Sensitizer Dispersion (Solution C) 40 parts of oxalic acid di-p-methylbenzyl ester (trade name: HS-3520, manufactured by DIC) and polyvinyl alcohol (polymerization degree 500, saponification degree 88%) 40 parts of a 10% aqueous solution and 20 parts of water are mixed, and the median diameter becomes 1.0 ⁇ m by a laser diffraction type particle size analyzer SALD2200 (manufactured by Shimadzu Corporation) using a sand mill (manufactured by IMEX Co., Ltd., sand grinder). This was crushed to obtain a sensitizer dispersion liquid (liquid C).
• thermosensitive recording medium After drying a coating material for an intermediate layer, a coating solution for an undercoat layer, a coating solution for a heat-sensitive recording layer, and a coating solution for recording on a protective layer, on one surface of a high-quality paper having a basis weight of 60 g / m 2. Is applied and dried so that the coating amount of each is 0.1 g / m 2 , 3.0 g / m 2 , 4.0 g / m 2 , and 2.0 g / m 2. After sequentially forming a layer and a protective layer, the surface was smoothed with a super calender to obtain a thermosensitive recording medium.
• Example 2 In the preparation of the undercoat layer coating liquid of Example 1, 412 parts of hollow particles A (trade name: A-170, manufactured by Sansui, solid content concentration 17.0%, hollow ratio 72%) were replaced with hollow particles B (trade name: A-380 (manufactured by Sansui Co., solid content concentration: 13.0%, hollowness: 78%) except that 539 parts were used to obtain a thermosensitive recording medium.
• hollow particles A trade name: A-170, manufactured by Sansui, solid content concentration 17.0%, hollow ratio 72%) were replaced with hollow particles B (trade name: A-380 (manufactured by Sansui Co., solid content concentration: 13.0%, hollowness: 78%) except that 539 parts were used to obtain a thermosensitive recording medium.
• Example 3 A heat-sensitive recording material was obtained in the same manner as in Example 1 except that zirconium nitrate was used as the borax of the coating solution for the intermediate layer in Example 1.
• Example 4 A heat-sensitive recording material was obtained in the same manner as in Example 1 except that zirconium chloride was used as the borax of the coating solution for the intermediate layer in Example 1.
• thermosensitive recording medium was obtained in the same manner as in Example 1 except that the intermediate layer coating layer of Example 1 was not provided.
• Comparative Example 2 In preparing the undercoat layer coating liquid of Example 1, 412 parts of hollow particles A (trade name: A-170, manufactured by Sansui Co., solid content concentration: 17.0%, hollow ratio: 72%) were replaced with hollow particles C (trade name: A heat-sensitive recording material was obtained in the same manner as in Example 1 except that 264 parts of Lowpaque SN-1055, manufactured by Dow Chemical Company, solid content concentration: 26.5%, hollow ratio: 55%).
• a bar code was recorded using a label printer (trade name: L-2000, manufactured by Ishida), and the recorded image quality was visually observed and evaluated according to the following criteria. :: There are no white spots in the image quality and no thick bar code, and there is no problem at all. ⁇ : There is almost no white spots in the image quality and no thickening of the bar code, and there is no practical problem. ⁇ : There are white spots on the image and thick barcodes, which is a practical problem.

Landscapes

• Physics & Mathematics (AREA)
• Optics & Photonics (AREA)
• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• General Chemical & Material Sciences (AREA)
• Heat Sensitive Colour Forming Recording (AREA)

Priority Applications (2)

Applications Claiming Priority (2)

Publications (1)

Family

ID=69951368

Family Applications (1)

Country Status (3)

Cited By (1)

Citations (9)

Family Cites Families (1)

• 2019
  • 2019-09-24 EP EP19864836.2A patent/EP3858633A4/de active Pending
  • 2019-09-24 JP JP2020549232A patent/JPWO2020067045A1/ja active Pending
  • 2019-09-24 WO PCT/JP2019/037329 patent/WO2020067045A1/ja unknown

Patent Citations (9)

Non-Patent Citations (1)

Also Published As

Similar Documents

Legal Events