JPH04275178A - heat sensitive recording material - Google Patents

Abstract

PURPOSE:To provide a thermosensible recording material characterized by that an epoxy group-containing diphenylsulfone derivative is contained in a thermal color forming layer having an overcoat layer and excellent in oil resistance. CONSTITUTION:In a thermosensible recording material wherein a thermal color forming layer is provided on a support and an overcoat layer based on a water- soluble resin, a crosslinking agent and pigment is provided thereon, an epoxy group-containing diphenylsulfone derivative such as 4-(2-methyl-glycidyloxy)-4'- benzyloxydiphenylsulfone or 4-(2-ethyl-glycidyloxy)-4'-(p-methylbenzyloxy) diphenylsulfone is added to the thermal color forming layer in a ratio of 0.1-20 pts.wt. per 100 pts.wt. of the solid components of the thermal color forming layer.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat-sensitive recording material, and more specifically, it relates to a heat-sensitive recording material having excellent oil resistance, water resistance, and vinyl chloride wrap resistance for use in heat-sensitive labels and the like.

0002

[Prior Art] A thermosensitive recording medium is generally made of a support made of paper, synthetic paper, or plastic film, and is coated with a colorless or light-colored color-forming substance such as an electron-donating leuco dye and an electron-accepting phenolic compound. A heat-sensitive coloring layer containing an organic acidic substance (developer) and an adhesive as main components is provided, and color recording is performed by causing these color-forming dyes and the developer to react with thermal energy. You can get the image.

[0003] Such heat-sensitive recording media has the advantages that the recording device is compact, inexpensive, and easy to maintain, and is used only as a recording medium for facsimile machines, automatic ticket vending machines, and scientific measuring instruments. Not POS label, C
It is widely used in various printers and plotters for AD, CRT medical images, etc.

However, conventional heat-sensitive recording materials have a problem in that when they come into contact with oil or plasticizer, the recording density decreases, or in severe cases, the recording disappears altogether. For example, when a heat-sensitive label with a pressure-sensitive adhesive (adhesive) layer provided on the back side of a heat-sensitive recording material is attached to a PVC film, polypropylene film, etc. as a POS label, the plasticizer contained in the film is transferred to the back side of the label. There was a problem that the plasticizer migrated from the film that came into direct contact with the label surface, making the barcode and characters printed on the label unreadable. Furthermore, even if oils such as edible oils and industrial oils come into contact with the heat-sensitive label affixed to the above-mentioned film, there is a problem in that the recording part disappears or becomes illegible, similar to the case with plasticizers.

In order to solve this problem, an attempt was made to provide an overcoat layer on the surface of the heat-sensitive layer (Japanese Utility Model Publication No. 59-9909).
However, if there is a minute defect in the overcoat layer, oil or plasticizer will penetrate from that area and diffuse into the heat-sensitive coloring layer, causing the entire printed area to disappear over a long period of time. There was a problem.

[0006]

[Problems to be Solved by the Invention] The present invention aims to prevent discoloration of the heat-sensitive recording area even if oil or plasticizer penetrates through minute defects in the overcoat layer of a heat-sensitive recording medium provided with an overcoat layer. Furthermore, by improving the oil resistance of the support, the purpose is to prevent oil and plasticizer penetrating from the cross section and back surface of the support from reaching the thermosensitive coloring layer.

[0007]

[Means for Solving the Problems] The present inventors have improved not only the plasticizer resistance of the heat-sensitive recording material but also the resistance of the heat-sensitive recording material to the plasticizer by immersing the heat-sensitive recording material in oil. As a result of research into improving oil resistance so that the color does not fade even when oil penetrates, the present invention has been completed.

That is, the present invention provides colorless coating on one side of the support.
Alternatively, a heat-sensitive coloring layer containing as main components a light-colored electron-donating leuco dye, an organic acidic substance (color developer) that develops the color of the leuco dye when heated, and an adhesive is provided, and a water-soluble resin is further disposed on the heat-sensitive coloring layer. , in a heat-sensitive recording material provided with an overcoat layer containing a crosslinking agent and a pigment as main components, by incorporating a diphenylsulfone derivative represented by the following general formula (1) into the heat-sensitive coloring layer, an overcoat can be obtained. It was possible to improve the printing on the heat-sensitive coloring layer to a level where it could be sufficiently read even if oil or plasticizer penetrated from the layer's minute defects, the cross section of the support, or the back surface.

[0009]

[Formula 1] However, R2 and R3 each represent a halogen atom, an alkyl group, or an alkoxy group, and R4 is a C1 to C8
represents an alkyl group. Further, l and m each represent 0 or an integer of 1 to 5, and n and p each represent an integer of 1 to 5. q is 0 or an integer from 1 to 4; r is 0 or an integer from 1 to 4;
Indicates an integer of 5.

In the diphenylsulfone derivative represented by formula (1), R4 in formula (1) is hydrogen and R3 is R1
Compared to the epoxy group-containing derivatives shown in , they have weaker physiological activity and are often negative in mutagenicity tests (Ames test) using Salmonella.

In addition, the oil resistance and plasticizer resistance of the heat-sensitive coloring layer of the present invention are relatively weak immediately after heat coloring, and sufficient durability cannot be obtained until about 12 hours have elapsed. By containing an oil repellent to suppress the speed at which oil and plasticizer diffuse into the heat-sensitive coloring layer, and by setting the oil resistance time of the support to 3 minutes or more, it is possible to prevent oil from leaking from the cut cross section or back side of the support. By suppressing penetration and preventing oil from reaching the heat-sensitive coloring layer until the durability of the heat-sensitive coloring layer has sufficiently improved, the oil resistance and plasticizer resistance of the printed area are made sufficiently strong. be able to. For example, even if a heat-sensitive label with barcodes or characters printed by a label printer is immersed in oil at room temperature for one week, the printed portion can be maintained at a sufficiently readable level.

[0012] To determine the oil resistance time of the support, commercially available salad oil (edible blended oil, manufactured by Ajinomoto Co., Inc.) was placed in a black plastic dish, and the support with a size of 5 cm x 5 cm was floated on top of the salad oil. When salad oil permeates into the support, spots appear on the surface, and the oil resistance time can be determined by measuring the time until 10 spots appear in a 5 cm square area. If the oil resistance time was 3 minutes or more, the printed portion of the heat-sensitive label made using the support was sufficiently legible even if it was immersed in oil for one week after printing.

The diphenylsulfone derivative represented by the above general formula (1) used in the present invention is, for example, 4-(2
-Methyl-1,2-epoxyethyl)diphenylsulfone, 4-(2-ethyl-1,2-epoxyethyl)diphenylsulfone, 4-(2-methyl-glycidyl)diphenylsulfone, 4-(2-ethyl-glycidyl) ) diphenylsulfone, 4-(2-butyl-glycidyl)diphenylsulfone, 4-(3-methyl-3,4-epoxybutyl)diphenylsulfone, 4-(2-methyl-2,
3-epoxybutyl)diphenylsulfone, 4-(2-
Methyl-1,2-epoxyethyloxy)diphenylsulfone, 4-(2-methyl-1,2-glycidyloxy)diphenylsulfone, 4-(2-methyl-2,3-epoxybutyloxy)diphenylsulfone, 4- (2-
Methyl-glycidyloxy)-4'-chlorodiphenylsulfone, 4-(2-methyl-glycidyloxy)-4
'-Bromodiphenylsulfone, 4-(2-methyl-glycidyloxy)-4'-methyldiphenylsulfone,
4-(2-Methyl-glycidyloxy)-4'-ethyldiphenylsulfone, 4-(2-methyl-glycidyloxy)-2',4'-dimethyldiphenylsulfone, 4
-(2-Methyl-glycidyloxy)-2',4'-dichlorodiphenylsulfone, 4-(2-methyl-glycidyloxymethoxy)diphenylsulfone, 4-(2-
methyl-glycidyloxy)-4'-(P-methylbenzyloxy)diphenylsulfone, 4-(2-ethyl-
glycidyloxy)-4'-(P-methylbenzyloxy)diphenylsulfone, 4-{2-(n-propyl)
-glycidyloxy}-4'-(P-methylbenzyloxy)diphenylsulfone, 4-(2-isopropyl-
glycidyloxy)-4'-(P-methylbenzyloxy)diphenylsulfone, 4-(2-butyl-glycidyloxy)-4'-(P-methylbenzyloxy)diphenylsulfone, 4-(2-hexyl-glycidyloxy) )-4'-(P-methylbenzyloxy)diphenylsulfone, 4-{2-(2-ethylhexyl)-glycidyloxy}-4'-(P-methylbenzyloxy)diphenylsulfone, 4-(2-methyl- glycidyloxy)-4'-isoamyldiphenylsulfone, 4-(2
-methyl-glycidyloxy)-4'-methoxydiphenylsulfone, 4-(2-methyl-glycidyloxy)
-4'-ethyloxydiphenyl sulfone and the like. Of course, the compounds are not limited to these, and two or more kinds of compounds can be used in combination if necessary. In the present invention, the amount of the diphenylsulfone derivative blended is preferably 0.1 to 20 parts by weight, preferably 0.5 to 10 parts by weight, based on 100 parts by weight of the solid content of the heat-sensitive coloring layer.

[0014] As the color-forming dye, a colorless or light-colored electron-donating dye that can develop color by reacting with a color developer under heating is used. The color-forming dye used in the present invention is
For example, 2,2bis{4-[6'-(N-cyclohexyl-N-methylamino)-3'-methylspiro[phthalido-3,9'-xanthene]-2'-ylamido]phenyl}propane, 3- diethylamino-6-methyl-7
-anilinofluorane, 3-piperidino-6-methyl-
7-anilinofluorane, 3-(N-ethyl-N-cyclohexylamino)-6-methyl-7-anilinofluorane, 3-diethylamino-7-chloroanilinofluorane, 3-[N-ethyl- N-(p-methylphenyl)
Amino]-6-methyl-7-anilinofluorane, 3-
Diethylamino-7-(metatrifluoromethyl)anilinofluorane, 3-[N-ethyl-N-tetrahydrofurfuryl]amino-6-methyl-7-anilinofluorane, 3-[N-ethyl-N- Isopentylamino]-
It consists of at least one member of fluoran dyes such as 6-methyl-7-anilinofluorane and 3-[N,N dibutylamino]-6-methyl-7-anilinofluorane.

The color developer used in the present invention is composed of an electron-accepting organic acidic substance capable of reacting with a color-forming dye under heating to develop color. Such a color developer liquefies or vaporizes at room temperature or higher, preferably 70° C. or higher, and reacts with the color-forming dye to develop color.

Examples of the color developer used in the present invention include 4,4'-isopropylidene diphenol (bisphenol A), 4,4'-isopropylidene bis(2-
chlorophenol), 4,4'-isopropylidene bis(2-methylphenol), 4,4'-isopropylidene bis(2,6-di-tert-butylphenol), 4
, 4'-disec-butylidene diphenol, 4,4'
-Cyclohexylidene diphenol, 4-tert-butylphenol, 4-phenylphenol, 4-hydroxydiphenoxide, naphthol, β-naphthol, methyl-4-hydroxybenzoate, 4-hydroxy-
Acetophenone, salicylic acid anilide, novolac type phenolic resin, halogenated novolac type phenolic resin, 4,4'-thiobis(3-methyl-6-tert-butylphenol), propyl p-hydroxybenzoate,
Isopropyl p-hydroxybenzoate, butyl p-hydroxybenzoate, benzyl p-hydroxybenzoate, p
-Aliphatic carboxylic acids such as methylbenzyl hydroxybenzoate, oxalic acid, maleic acid, tartaric acid, citric acid, succinic acid, stearic acid, benzoic acid, p-tert-butylbenzoic acid, phthalic acid, gallic acid, salicylic acid, 3 -isopropylsalicylic acid, 3,5-di-α-methylbenzylsalicylic acid, bis(4-hydroxyphenyl) sulfide, 1,7-di(4-hydroxyphenylthio)-3,
5-dioxaheptane, p-nitrobenzoic acid, and these organic color developers such as zinc, magnesium, aluminum,
Salts with polyvalent metals such as calcium, titanium, manganese, tin, nickel, etc., 4,4'-dihydroxydiphenylsulfone, 2,4'-dihydroxydiphenylsulfone, 3
, 3'-dihydroxydiphenylsulfone, 3,3
'-Diamino-4,4'-dihydroxy-diphenylsulfone, 3,3'-diallyl-4,4'-dihydroxy-diphenylsulfone, 3,3'-dichloro-4,4'
-dihydroxydiphenylsulfone, 4-hydroxy-
Diphenylsulfone, 4-hydroxy-4'-isopropyldiphenylsulfone, 4-hydroxy-4'-isopropyloxydiphenylsulfone, 4-hydroxy-
4'-benzyloxydiphenylsulfone, 2,4-dihydroxy-diphenylsulfone, 2,4-dihydroxy-4'-methyldiphenylsulfone, and 3,4-
It consists of at least one member selected from dihydroxyphenyl-p-trisulfone and the like. The developer is usually mixed and used in an amount of 1 to 5 parts by weight, preferably 1.5 to 3 parts by weight, per 1 part by weight of the color-forming dye.

[0017] In the present invention, as the adhesive contained in the heat-sensitive coloring layer, all conventional adhesives for heat-sensitive coloring layers can be used. However, it is preferable that the mixed liquid does not develop color, aggregate, or become highly viscous when mixed with the respective dispersions of the color-forming dye and color developer; The heat-sensitive recording layer film is required to be tough and to have no desensitizing effect.

Common water-soluble adhesives include polyvinyl alcohol, modified starch, gum arabic, gelatin, casein, chitosan, methylcellulose, hydroxyethylcellulose, hydroxymethylcellulose, polyvinylpyrrolidone, polyacrylate, polyacrylamide, and styrene-anhydrous. Maleic acid copolymer, methyl vinyl ether-maleic anhydride copolymer, isopropylene-maleic anhydride copolymer are used, and water-dispersible adhesives include styrene-butadiene latex, vinyl acetate-acrylic acid ester copolymer emulsion, and polyurethane. Emulsions, polyvinyl chloride emulsions, polyvinylidene chloride emulsions, methacrylic ester copolymer emulsions, acrylic ester copolymer emulsions, and the like can be used.

In order to strengthen the water resistance of the coating film, reactive groups such as acetoacetyl groups, carboxyl groups,
Alternatively, it is preferable to use a water-soluble and/or water-dispersible polymer substance containing an amide or the like in combination with a crosslinking agent.

Examples of crosslinking agents for water-soluble polymeric substances include dialdehyde compounds such as glyoxal and polyaldehyde, polyamine compounds such as polyethyleneimine, epoxy compounds, polyamide resins, diglycidyl compounds such as glycerin diglycidyl ether, Dimethylolurea compounds, aziridine compounds, blocked isocyanate compounds, and inorganic compounds such as ammonium persulfate, ferric chloride, magnesium chloride, and the like can be used.

[0021] The heat-sensitive coloring layer may contain a pigment, particularly a white pigment, if necessary. Such pigments include
For example, 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 inorganic fine powders such as calcium carbonate and silica, and urea-formalin. Examples include organic resin fine powder such as resin, styrene/methacrylic acid copolymer, and polystyrene resin.

[0022] When the thermosensitive color forming layer is heated, a thermoplastic substance that melts at a lower temperature than the color forming dye or color developer, forms a eutectic with the color forming dye and color developer, and can develop color at a low temperature. , and a thermofusible substance that can improve the stability after coloring can be mixed into the thermosensitive coloring layer coating.

Examples of thermofusible substances include stearic acid amide, stearic acid ethylene bisamide, oleic acid amide, palmitic acid amide, coconut fatty acid amide,
Fatty acid amides such as behenic acid amide, zinc stearate, calcium stearate, polyethylene wax,
Waxes (or lubricants) such as carnauba wax, paraffin wax, and ester wax, dimethyl terephthalate, dibutyl terephthalate, dibenzyl terephthalate, dibutyl isophthalate, phenyl 1-hydroxynaphthoate, 1,2
-di(3-methylphenoxy)ethane, 1,2-diphenoxyethane, 1-phenoxy-2-(4-methylphenoxy)ethane, diphenyl carbonate, p-benzylbiphenyl, 2,2'-methylenebis(4-methyl -6-t-
butylphenol), 4,4'-butylidene bis(6-
t-butyl-3-methylphenol), 1,1,3-tris(2-methyl-4-hydroxy-5-t-butylphenyl)butane, 2,2'-methylenebis(4-ethyl-6-t- butylphenol), 2,4-di-t-butyl-3-methylphenol, 4,4'-thiobis(
Hindered phenols such as 3-methyl-6-t-butylphenol), sensitizers such as 2-(2'-hydroxy-5'-methylphenyl)-benzotriazole, and 2-hydroxy-4-benzyloxybenzophenone ,
Examples include antioxidants and ultraviolet absorbers. Generally, it is preferable that the thermofusible substance is contained in the thermosensitive coloring layer in a proportion of 4 parts by weight or less per 1 part by weight of the color developer.

[0024] It is added to the heat-sensitive coloring layer of the present invention to suppress oil and plasticizer from penetrating into the heat-sensitive coloring layer until the oil resistance and plasticizer resistance of the heat-sensitive coloring layer improve after heat coloring. It is effective to use a fluorine-based oil repellent. The oil repellent may be mixed with the heat-sensitive coloring layer paint, or may be added to one or more of the constituent particles of the heat-sensitive coloring layer, such as color-forming dyes, color developers, diphenylsulfone derivatives, and thermofusible substances. It is desirable to mix the components during dispersion of the dispersion so that they are adsorbed onto the surfaces of the dispersion particles.

Color-forming dyes, color developers, diphenylsulfone derivatives, and thermofusible substances are usually supplied in the form of powder, so they are mixed with water and used in ball mills, sand grinders, attritors, ultravisco mills, dyno mills, etc. It is used after being ground to a particle size of 0.1 to 10 μm using a dispersing machine.During this operation, an oil repellent is added, and in order to further increase the dispersion efficiency and improve the stability of the dispersion, a dispersant or water-soluble It is desirable to use it together with a synthetic resin.

[0026] The oil repellent is, for example, fluoroalkyl (C2
~C20) carboxylic acid, perfluoroalkyl (C7~
C13) carboxylic acid, 3-{fluoroalkyl (C6~
C11) Sodium oxy}-1-alkyl (C3-C4) sulfonate, 3-{ω-fluoroalkanoyl (C
6-C8)-N-ethylamino}-1-propanesulfonate sodium, N-{3-(perfluorooctanesulfonamido)propyl}-N,N-dimethyl-N-carboxymethylene ammonium betaine, perfluoroalkyl ( C4-C12) sulfonate, perfluorooctane sulfonic acid diethanolamide, perfluoroalkyl (C6-C10) sulfonamidopropyl trimethylammonium salt, perfluoroalkyl (C6-C10)
C10) -N-ethylsulfonylglycine salt, N-perfluorooctanesulfonylglutamate disodium, N-propyl-N-(2-hydroxyethyl)perfluorooctanesulfonamide, N-{3-(perfluorooctanesulfonamide) propyl}-N,N-dimethyl-N-cargiphosymethylene ammonium betaine, bis(N-perfluorooctylsulfonyl-
There are surfactants such as N-ethylaminoethyl), monoperfluoroalkyl (C6-C16) ethyl phosphate, and polymeric compounds containing these fluorine-containing moieties in their molecular structures.

[0027] The amount of oil repellent added is 10% of the solid content of the heat-sensitive coloring layer.
It is desirable to add 0.1 to 10 parts per 0 parts. 0.
If the amount is less than 1 part, the oil repellency is insufficient, and if it exceeds 10 parts, there are drawbacks such as poor coating properties of the overcoat layer applied on the heat-sensitive coloring layer and increased cost.

[0028] If necessary, auxiliary additive components conventionally used in heat-sensitive recording materials, such as dispersants and surfactants, may be added to the heat-sensitive coloring layer. The coating amount of the heat-sensitive coloring layer is generally preferably 3 to 10 g/m2. As the coating method, methods conventionally used by those skilled in the art, such as a Meyer bar method, an air knife method, a blade method, a reverse roll method, and a slit die method, can be used. Furthermore, recording density and sensitivity can be improved by smoothing the surface of the heat-sensitive coloring layer using a super calender, a gloss calender, a machine calender, or the like.

The support used in the present invention may be wood-free paper, medium-quality paper, recycled paper, or coated paper. Furthermore, in order to improve the oil resistance of the heat-sensitive label, it is very effective to increase the oil resistance time of the support to 3 minutes or more to prevent oil from penetrating through the cut cross section and back surface of the support.

[0030] In order to increase the oil resistance time of the support to 3 minutes or more, in the case of high-quality paper, medium-quality paper, and recycled paper, it is necessary to increase the amount of internally added adhesive at the papermaking stage, or add an oil repellent to the pulp fibers. This can be achieved by lowering the surface tension of the pulp fibers and making them difficult to wet with oil. Furthermore, it is also possible to increase the amount of adhesive in the size liquid in the size press process, or add an oil repellent. It is also possible to impregnate paper that has already been made with an adhesive and/or an oil repellent.

Furthermore, it is also possible to provide a coating layer with a high adhesive ratio on one or both sides of the paper. When a coating layer is provided, if the coating layer is on one side, it is desirable to have a structure on which a heat-sensitive coloring layer and an overcoat layer are provided. As a coating method, an on-machine coater such as a bill blade method or a gate roll method, or an off-machine coater such as an air knife method, a blade method, a reverse roll method, a Meyer bar method, or a slit die method can be used.

The adhesive for internal addition can be appropriately selected from among the water-soluble adhesives exemplified as adhesives for the heat-sensitive coloring layer, but it is desirable to use one with relatively low viscosity. Adhesive for internal addition is 0.5 to 5 for pulp fiber.
It is desirable to add it at a rate of %.

The oil repellent can be appropriately selected from among those exemplified for dispersing color-forming dyes, color developers, diphenylsulfone derivatives, and thermofusible substances. The amount added is preferably 0.1 to 10% based on the solid content of the paint. The paint used for size pressing, impregnation, and coating contains a water-soluble or water-dispersible adhesive, a pigment, and, if necessary, an oil repellent and a crosslinking agent.

Water-soluble and water-dispersible adhesives preferably have good film-forming properties, have a low film surface tension, and are insoluble in oil, but they can be appropriately selected from those exemplified for the heat-sensitive coloring layer. can do. Pigments, oil repellents, and crosslinking agents can also be appropriately selected from those exemplified for the heat-sensitive coloring layer. The adhesive/pigment ratio is high,
It is necessary to maintain good barrier properties. Adhesive/pigment=1
Coating amount is 1 to 10 g/m in the range of 00/0 to 50/50
It is desirable to set it within the range of 2.

The overcoat layer provided on the heat-sensitive coloring layer of the present invention has a coating weight of 0.00% after drying of a paint containing a water-soluble or water-dispersible adhesive, a crosslinking agent, a pigment and, if necessary, a lubricant. 5-5.0g/m2, preferably 1.0-4
．． It can be obtained by coating at 0g/m2. Coating amount is 0
．． If it is less than 5 g/m2, the coating film will not be formed uniformly, resulting in an increase in pinholes and coating defects through which oil and plasticizer will penetrate, causing a decrease in oil resistance and plasticizer resistance.

If the coating amount exceeds 5.0 g/m2, there is a drawback that the sensitivity decreases and the print density becomes thin. In addition, the resin/pigment ratio of the overcoat layer is preferably in the range of 80/20 to 40/60; if the resin compounding ratio exceeds 80%, sticking may occur during printing, or adhesion of printing ink during label processing. There is a problem of decreased sex. Furthermore, if the blending ratio of the resin is less than 40%, the barrier properties of the coating film will be low, and the oil resistance and plasticizer resistance will decrease. The adhesive, crosslinking agent, and pigment used in the overcoat layer can be those used in the heat-sensitive layer and the oil penetration prevention coating, and the same coating method can be used.

[0037] If necessary, a back layer may be provided on the opposite side of the heat-sensitive color forming layer of the heat-sensitive recording material of the present invention to correct curling. The same paint and coating method as for the overcoat layer may be used for the back layer, and the coating amount and resin/pigment ratio may be changed as necessary.

[0038]

[Examples] The present invention will be explained in more detail with reference to Examples below, but the scope of the present invention is of course not limited to these. In each example, "parts" indicate "parts by weight." The following solutions A to I were prepared and used in each of the following examples.

Liquid A (thermochromic dye dispersion) 3-(N-ethyl-N-isoamylamino)-
6-methyl-7-anilinofluorane

5 parts 10% methyl vinyl ether-maleic anhydride copolymer aqueous solution
Part 5 Water

Part 8

[
Liquid B (contains oil repellent, heat-sensitive coloring dye dispersion)
3-(N-ethyl-N-isoamylamino)-6-methyl-7-anilinofluorane

5 parts 10% methyl vinyl ether-maleic anhydride copolymer aqueous solution
Part 5 Fluorine oil repellent (Asahi Guard AG-
530, solid content 15%, manufactured by Asahi Glass Co., Ltd.)

Part 3
water

7th part

Liquid C (color developer dispersion) 2,4-dihydroxy-diphenylsulfone
30 copies
10% methyl vinyl ether-maleic anhydride copolymer aqueous solution 30 parts water

3
4th part

Liquid D (contains oil repellent, color developer dispersion) 2,4
-dihydroxy-diphenylsulfone
30 parts 10% methyl vinyl ether-maleic anhydride copolymer aqueous solution
30 parts Fluorine oil repellent (Asahi Guard AG-
530, solid content 15%, manufactured by Asahi Glass Co., Ltd.)

20 parts water

23 parts

Liquid E (diphenylsulfone derivative dispersion)
4-(2-Methyl-glycidyloxy)-4'-benzyloxy diphenyl sulfone

10 parts 10% methyl vinyl ether-maleic anhydride copolymer aqueous solution 10 parts
water

Part 11

Liquid F (containing oil repellent, diphenylsulfone derivative dispersion) 4-(2-methyl-glycidyloxy)-
4'-benzyloxy diphenyl sulfone
10 parts Fluorine oil repellent (Asahi Guard AG-530, solid content 15%,
Manufactured by Asahi Glass Co., Ltd.)

7 parts 10% methyl vinyl ether-maleic anhydride copolymer aqueous solution 10 parts
water

7th part

Liquid G (containing oil repellent, diphenylsulfone derivative dispersion) 4-(2-ethyl-glycidyloxy)-
4'-(p-methylbenzyloxy)diphenylsulfone
10 parts Fluorine oil repellent (Asahi Guard AG-530, solid content 15%, manufactured by Asahi Glass Co., Ltd.)
7
Parts 10% methyl vinyl ether-maleic anhydride copolymer aqueous solution 10 parts Water


7th part

Liquid H (thermofusible substance dispersion) Stearic acid amide

30 parts Dispersant (sodium polyacrylate, solid content 40%) 1.
5 parts 10% methyl vinyl ether-maleic anhydride copolymer aqueous solution 30 parts Water


35 copies

Liquid I (containing oil repellent, thermofusible substance dispersion)
stearic acid amide

30 parts Dispersant (sodium polyacrylate, solid content 40%) 1.5 parts
Fluorine oil repellent (Scotchban FC-829, solid content 30%, manufactured by Sumitomo 3M)

3 parts 10% methyl vinyl ether-maleic anhydride copolymer aqueous solution
30 parts water

34 parts A liquid~
Each liquid I was separately dispersed and pulverized using an Ultra Visco Mill, and the average particle size was adjusted to 1 μm or less.

Example 1 35 parts of liquid A, 90 parts of liquid C, 8 parts of liquid E, 14 parts of liquid H, 60 parts of liquid
% calcium carbonate slurry, 40 parts of 10% polyvinyl alcohol aqueous solution, SBR latex (OX-10
60 Solid content 50%, manufactured by Nippon Zeon Co., Ltd.) 32 parts,
and 59 parts of water were mixed to prepare a heat-sensitive coloring layer paint. A papermaking raw material consisting of Canadian Standard Freeness, 100 parts of hardwood bleached kraft pulp beaten to 450 cc, 8 parts of talc, 0.5 part of petroleum-based sizing agent, and 0.5 part of sulfuric acid was prepared, and paper was made to have a basis weight of 64 g/m2. The coating amount of the above heat-sensitive coloring layer paint on one side of the paper after drying is 8g/m2.
It was coated to form a heat-sensitive coloring layer.

The following overcoat layer paint was applied on the heat-sensitive coloring layer so that the coating weight after drying was 3.0 g/m2, and the following back layer paint was applied on the opposite side after drying. After coating so that the coating amount is 1.5g/m2,
After smoothing with a super calender, the Oken type smoothness (J. TAPPI No. 5) of the overcoat layer was 8.
A heat-sensitive recording medium for 50 seconds was obtained.

Overcoat layer paint 60% kaolinite clay slurry
40 copies 1
0% modified polyvinyl alcohol aqueous solution
300 parts 10% casein solution
200 parts 30% zinc stearate dispersion
13 parts dimethylolurea crosslinking agent
Part 15 Water

300 parts were mixed to form an overcoat layer paint.

Back layer paint 10% oxidized starch aqueous solution
300 parts 10% polyvinyl alcohol aqueous solution
100 copies water

1
00 copies

Example 2 35 parts of liquid B, 90 parts of liquid D, 8 parts of liquid F, 14 parts of liquid I, 60 parts
% calcium carbonate slurry, 40 parts of 10% polyvinyl alcohol aqueous solution, SBR latex (OX-10
60 Solid content 50%, manufactured by Nippon Zeon Co., Ltd.) 32 parts,
and 59 parts of water were mixed to prepare a heat-sensitive coloring layer paint. In the same manner as in Example 1, a heat-sensitive coloring layer, an overcoat layer, and a back layer were coated on the base paper of Example 1, and a smoothing treatment was performed to obtain a heat-sensitive recording material.

Example 3 35 parts of liquid B, 90 parts of liquid D, 8 parts of liquid G, 14 parts of liquid I, 60 parts
% calcium carbonate slurry, 40 parts of 10% polyvinyl alcohol aqueous solution, SBR latex (OX-10
60 Solid content 50%, manufactured by Nippon Zeon Co., Ltd.) 32 parts,
and 59 parts of water were mixed to prepare a heat-sensitive coloring layer paint. In the same manner as in Example 1, a heat-sensitive coloring layer, an overcoat layer, and a back layer were coated on the base paper of Example 1, and a smoothing treatment was performed to obtain a heat-sensitive recording material.

Example 4, Example 5, Example 6 The base paper used in Example 1 was coated with starch/fluorine oil repellent (Scotchban FC-807, solid content 33%, Sumitomo 3M) using a size press.
Coating amount after drying of paint of 95/5 is 1.0 g/m
Example 1,
The heat-sensitive coloring layer paints used in Examples 2 and 3 were applied in the same manner to obtain heat-sensitive recording bodies. The oil resistance time of the support was 5 minutes.

Comparative Example 1 35 parts of liquid A, 90 parts of liquid C, 14 parts of liquid H, 45 parts of 60% calcium carbonate slurry, 40 parts of 10% polyvinyl alcohol aqueous solution, SBR latex (OX-1060 solid content 50%, Nippon Zeon) Co., Ltd., and 57 parts of water were mixed to prepare a heat-sensitive coloring layer paint. One side of the support base paper prepared in Example 1 was coated and smoothed in the same manner as in Example 1 to obtain a heat-sensitive recording material.

After coating an acrylic adhesive on a release paper with a thickness of 65 μm so that the coated amount after drying was 25 g/m 2 , the thermal recording materials of Examples 1 to 6 and Comparative Example 1 were each coated. A heat-sensitive label was created by pasting it with the back side of the paper. After cutting this thermal label into a predetermined width, a label printer (DP)
-110GS (manufactured by Teraoka Seiko Co., Ltd.) were used to print barcodes and characters, and tests were conducted on the items shown in Table 1.

The results are shown in Table 1, and the barcodes and letters of the samples of Examples remained and were sufficiently readable, but the samples of Comparative Example immersed in salad oil had no barcodes and letters. Both had disappeared and were unreadable.

[0058]

[Table 1] Print density: The density after printing was evaluated using a label printer DP-110GS (manufactured by Teraoka Seiko Co., Ltd.). ○: Good oil resistance: A heat-sensitive label attached to a vinyl chloride wrap film was immersed in salad oil (mixed salad oil, manufactured by Ajinomoto Co., Inc.), and the printed area was evaluated after one week had passed at 25°C. PVC wrap resistance: Cover the heat-sensitive label attached to the PVC wrap film with another PVC wrap film at 25℃.
The printed area was evaluated after one week had passed. Water resistance: A heat-sensitive label attached to a PVC wrap film was immersed in water, and the printed area was evaluated after one week had passed at 25°C. ◎: Almost no change ○: Characters are fully legible ×: Characters are not legible

[0059]

Effects of the Invention According to the present invention, it is possible to provide a heat-sensitive recording material that does not lose its color even if oil penetrates through the defective portions and cut cross sections of the overcoat layer of the heat-sensitive recording material subjected to label processing.

Claims (3)

[Claims] 1. A heat-sensitive coloring layer containing as main components a colorless or light-colored electron-donating leuco dye, an organic acidic substance that causes the leuco dye to develop color when heated, and an adhesive is provided on a support, and further the heat-sensitive coloring layer is provided on a support. In a thermosensitive recording material provided with an overcoat layer containing a water-soluble resin, a crosslinking agent, and a pigment as main components on the layer, the thermosensitive coloring layer contains a diphenyl sulfone derivative represented by the following general formula (1). A heat-sensitive recording material characterized by: [Formula 1] However, R2 and R3 each represent a halogen atom, an alkyl group, or an alkoxy group, and R4 is a C1 to C8
represents an alkyl group. Further, l and m each represent 0 or an integer of 1 to 5, and n and p each represent an integer of 1 to 5. q is 0 or an integer from 1 to 4; r is 0 or an integer from 1 to 4;
Indicates an integer of 5. 2. The heat-sensitive recording material according to claim 1, wherein a fluorine-based oil repellent is contained in the heat-sensitive coloring layer. 3. The heat-sensitive recording material according to claim 1, wherein the support has an oil resistance time of 3 minutes or more.