JPH0493285A - Thermal recording card - Google Patents

Abstract

PURPOSE:To improve optical reading properties in a near infrared region by a method wherein a substrate is a specific opaque polyester resin, a basic colorless dye is at least one of dyes forming a recording image and having absorption in a specific near infrared region, and an intermediate layer containing an oil absorbing pigment having non-absorption in a specific near infrared region is provided between the substrate and a thermal recording layer. CONSTITUTION:An opaque polyester resin of 100-500mum thickness containing 10-60wt.% calcium carbonate in a polyester resin is used as a substrate. Thereon, an intermediate layer containing an oil absorbing pigment having non-absorption in a 700-1200nm near infrared region and a near infrared light absorbing thermal recording layer containing a leuco dye having absorption in a 700-1200nm near infrared region are successively provided. It is desirable that the calcium carbonate has a particle diameter of 0.3-5mum and is contained in the amount of 10-60wt.% in the polyester resin. As the oil absorbing pigment, calcined clay, amorphous silica, and the like can be exemplified. As the near infrared light absorbing leuco dye, 2-methyl-6-p-(p-dimethylaminophenyl)aminoanilino fluorane or the like is especially desirable.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a heat-sensitive recording card with excellent optical readability in the near-infrared region.

(Prior art) In general, heat-sensitive recording sheets are produced by grinding and dispersing a colorless or light-colored basic colorless dye and an organic color developer such as a phenolic substance into fine particles, and then mixing them together, filling them with a binder, etc. A coating liquid obtained by adding agents, sensitivity improvers, lubricants, and other auxiliary agents is coated on a support such as paper, synthetic paper, film, or plastic. Color recording is obtained through an instantaneous chemical reaction caused by heating.

These thermal recording sheets are used in a wide range of fields such as measurement recorders, computers, terminal printers, facsimiles, automatic ticket vending machines, and barcode labels.
Recently, as these recording devices have become more diversified and more sophisticated, the quality required for thermosensitive recording sheets has also become more sophisticated. For example, as recording speeds increase, it is required to obtain clear colored images with high density even with minute thermal energy, and on the other hand, heat-sensitive recording sheets with excellent preservability such as light resistance, weather resistance, and oil resistance are required. requested.

On the other hand, in recent years, along with the rationalization of administrative processing, the near-infrared region (
Optical reading devices whose reading wavelength range is 700 to 120 hm) are becoming popular. For this reason, efforts are being made to develop basic dyes suitable for reading using near-infrared light and to apply them to thermosensitive recording paper.

However, when paper is used as a support, there are problems in that it may bend during use, or the support or the heat-sensitive recording layer on the support may be damaged by contact with water or oil.

(Problems to be Solved by the Invention) Therefore, the present inventors used a polyester resin containing barium sulfate or titanium oxide, which is currently well known as a card base material, as a support, and applied near-infrared light on this support. A near-infrared light-readable thermosensitive recording card was prepared by providing a thermosensitive coloring layer containing a light-absorbing leuco dye. However, it has been found that because the fillers barium sulfate and titanium oxide themselves absorb light in the near-infrared region (700 to 1200 nm), misreading occurs frequently when reading recorded images.

An object of the present invention is to provide a heat-sensitive recording card that uses a plastic base material and has excellent optical readability in the near-infrared region.

(Means for Solving the Problems) The present inventors conducted detailed research on near-infrared light absorption of fillers, and solved the above problems regarding supports at once.

That is, the heat-sensitive recording card of the present invention uses an opaque polyester resin having a thickness of 100 to 500 μI containing calcium carbonate in an amount of 10 to 60% by weight based on the polyester resin as a support, and on top of this an opaque polyester resin containing 10 to 60% by weight of calcium carbonate based on the polyester resin. an intermediate layer containing an oil-absorbing pigment that has no absorption in the outer region;
A heat-sensitive recording layer containing a near-infrared absorbing leuco dye having absorption in the near-infrared region of 700 to +200 Ωm is successively provided.

By containing calcium carbonate, the opacity of the resin film can be increased, but calcium carbonate has a
Since it does not absorb light in the near-infrared region of 0 to 1200 nm, it does not adversely affect the reading of recorded images. The particle size of calcium carbonate is preferably 0.3 to 5 μm, and its content is preferably 10 to 60% by weight based on the polyester resin. If the content is less than 10%, the opacity is low;
If it exceeds this, the toughness as a card base material will be impaired.

A polyester film containing calcium carbonate as a filler as described above can be obtained as follows. That is, calcium carbonate and additives are added to a polyester resin, mixed, melt-kneaded in an extruder, and then extruded through a grease slit to form a film. At this time, it may be stretched.

Further, in the heat-sensitive recording card of the present invention, an intermediate layer containing an oil-absorbing pigment having no absorption in the near-infrared region of 700 to 12Of)n+n is provided between the support and the recording layer. In the present invention, a pigment that does not absorb in the near-infrared region is defined as a pigment that absorbs 5% or less of near-infrared light with a wavelength of 700 to 12110111 measured by a near-infrared spectrophotometer, and is likely to be misread by a near-infrared light reader. It is not an oil-absorbing pigment.

Specific examples of such oil-absorbing pigments include calcined clay, amorphous silica, zinc oxide, magnesium oxide, aluminum oxide, aluminum hydroxide, magnesium carbonate, calcium carbonate, and the like. The binder used in the intermediate layer is selected from those exemplified for the heat-sensitive coloring layer described below. layers are provided.

The near-infrared light-absorbing leuco dye that has absorption in the near-infrared region of 700 to 1200 nm used in the present invention has the property of absorbing near-infrared light in the recorded image when it is thermally colored. Although not particularly limited, from the viewpoint of quality performance, the general formula (I), (
Particularly preferred are the compounds shown in n) and (III).

Examples of the near-infrared absorbing leuco dye of general formula (1) used in the present invention include, but are not limited to, the following.

2-Methyl-6-p-(p-dimethylaminophenyl)
Aminoanilinofluoran 2-methoxy-6-p-(p-dimethylaminophenyl)Aminoanilinofluoran 2-chloro-6-p-(p-dimethylaminophenyl)
Aminoanilinofluorane 2-nitro-6-p-(p-diethylaminophenyl)
Aminoanilinofluorane 2-amino-6-p-(p-diethylaminophenyl)
Aminoanilinofluoran 2-diethylamino-6-p-(p-diethylaminophenyl)aminoanilinofluoran 2-phenyl-6-
p-(p-phenylaminophenyl)aminoanilinofluorane 2-benzyl-6-p-(p-phenylaminophenyl)aminoanilinofluoran 2-hydroxy-6-p-(p-phenylaminophenyl)amino Anilinofluorane 3-methyl-6-p-(
p-dimethylaminophenyl)aminoanilinofluoran 3-diethylamino-6-p-(p-diethylaminophenyl)aminoanilinofluoran 3-diethylamino-6-p-(p-dibutylaminophenyl)aminoanilinofluoran 2-Methyl-6-p-(p-dimethylaminophenyl)aminoanilinofluorane 2-chloro-3-methyl-6-p-(p-phenylaminophenyl)aminoanilinofluoran General used in the present invention Examples of the near-infrared light absorption diameter leuco dye of formula (I[) include, but are not limited to, the following.

33-bis-[2-(p-dimethylaminophenyl)-
2-(p-methoxyphenyl)ethenylco-4567-
Tetrabromophthalide 33-bis-[2-(p-dimethylaminophenyl)-
2-(1)-Methoxyphenyl)ethenylco456.
7-Titrachlorophthalide 33-bis[1,1-bis(4-pyrrolidinophenyl)
ethylene-2-yl]-4.5.6.7-titrabromophthalide 3.3-bis[1-(4-methoxyphenyl)1-(4
-pyrrolidinophenyl)ethylene-2yl]-4,5,
6,7-Titrachlorophthalide Examples of the near-infrared absorbing leuco dye of general formula (m) used in the present invention include, but are not limited to, the following.

36-bis(dimethylamino)fluorene-9-subiro-3'-(6'-dimethylamino)phthalide 3.6-bis(diethylamino)fluorene-9spiro-3'-(6'-diethylamino)phthalide, In the present invention, general formulas (I), (n), (II
Of course, near-infrared light absorbing leuco dyes other than [) can also be used. Specifically, the following can be mentioned.

11-bis-[2',2',2',2'-tetrakis-(p-dimethylaminophenyl)-ethynyl]-
2,2-Dinitrilethane 11-bis-[2',2',2',2'-tetrakis-(p-dimethylaminophenyl)-ethynyl]-
2-β-naphthoylethane 11-bis-[2',2',2',2'-tetrakis-(p-dimethylaminophenyl)-ethynyl]-
2,2-Diacetylethane bis-[2,2,2',2'-tetrakis(p-dimethylaminophenyl)-ethynylcomethylmalonic acid dimethyl ester These near-infrared light-absorbing leuco dyes may be used alone or in combination. The above can be used in combination.

Further, as the organic color developer used in the present invention, bisphenol A, 4-hydroxybenzoic acid ester, 4-
Hydroxyphthalic acid diesters Phthalic acid monoesters, bis-(hydroxyphenyl) sulfides, 4-
Human 0xyphenylaryl sulfones, 4-hydroxyphenylaryl sulfonates, 1,3-di[2-
(Hydroxyphenyl)-2-propyl]-benzenes, 4-hydroxybenzoyloxybenzoic acid ester,
Bisphenol sulfones and other color developers are preferred, and specific examples thereof are shown below.

Bisphenol A 4.4'-isopropylidene diphenol (also known as bisphenol A) 44-cyclohexylidene diphenol p, p'-(1
-Methyl-n-hexylidene) diphenol 1, fuji(4-hydroxyphenylthio)-35-dioxahebutane 4-hydroxybenzoic acid esters Benzyl 4-hydroxybenzoate 4-hydroxybenzoic acid ethyl 4-hydroxybenzoic acid Isopropyl 4-hydroxybenzoate Butyl 4-hydroxybenzoate Isobutyl 4-hydroxybenzoate Methylbenzyl 4-hydroxybenzoate 4-Hydroxyphthalic acid diesters Dimethyl 4-hydroxyphthalate Diisopropyl 4-hydroxyphthalate 4-Hydroxyphthalate Dibenzyl 4-Hydroxyphthalate Dihexyl Phthalate Monoesters Monobenzyl Phthalate Monocyclohexyl Phthalate Monophenyl Phthalate Monomethyl Phenyl Phthalate Monoethylphenyl Phthalate Monopropyl Benzyl Phthalate Monohalogen Benzyl Phthalate Phthalic acid monoethoxybenzyl ester bis-(hydroxyphenyl) sulfides bis-(4-hydroxy-3-1e+I-butyl-6-methylphenyl) sulfide bis-(4-hydroxy-2,5-dimethylphenyl)
Sulfide bis-(4-hydroxy-2-methyl-5-ethylphenyl) sulfide bis-(4-hydroxy-2-methyl-5-isopropylphenyl) sulfide bis-(4-hydroxy-2,3-dimethylphenyl)
Sulfide bis-(4-hydroxy-2,5-diethylphenyl)
Sulfide bis-(4-hydroxy-25-diisopropylphenyl) sulfide bis-(4-hydroxy-236-)dimethylphenyl) sulfide bis-(2,4,5-trihydroxyphenyl) sulfide bis=(4-hydroxy-2 -cyclohexyl-5-methylphenyl)sulfidebis-(2,3,4-h-lyhydroxyphenyl)sulfidebis-(4,5-dihydroxy-2-tcrt-butylphenyl)sulfidebis-(4-hydroxy- 25-diphenylphenyl)
Sulfide bis-(4-hydroxy-2-ten-octyl 5-methylphenyl) sulfide 4-hydroxyphenylaryl sulfones 4-hydroxy-4'-isopropoxydiphenyl sulfone 4-hydroxy-4'-propoxydiphenyl sulfone 4-hydroxy -4' -n-Butyloxydiphenylsulfone 4-hydroxyphenylarylsulfonates 4-hydroxyphenylbenzenesulfonate 4-hydroxyphenyl-p-)lylsulfonate 4-hydroxyphenylmethylenesulfonate 4-hydroxyphenyl-p- 1eft-butylbenzenesulfonate 4-hydroxyphenyl-p-isopropoxybenzenesulfonate 4-hydroxyphenyl-1'-naphthalenesulfonate 4-hydroxyphenyl-2'-naphthalenesulfonate 1,3-di[2-(4 -hydroxyphenyl)2-propyl]benzene 1.3-di[2-(4-hydroxy-3-alkylphenyl)-2-propyl]benzene 1.3-di[2-(2
,4-dihydroxyphenyl)2-propyl]benzene 1,3-di[2-(2-hydroxy-5-methylphenyl)-2-propyl]benzene resorcinols 13-dihydroxy-6(α,α-dimethylbenzyl)
-Benzene 4-hydroxybenzoyloxybenzoate ester Hensyl 4-hydroxybenzoyloxybenzoate Methyl 4-hydroxybenzoyloxybenzoate Ethyl 4-hydroxybenzoyloxybenzoate Propyl 4-hydroxybenzoyloxybenzoate Butyl 4-hydroxybenzoyloxybenzoate Isopropyl 4-hydroxybenzoyloxybenzoate tertbutyl 4-hydroxybenzoyloxybenzoate Hexyl 4-hydroxybenzoyloxybenzoate Octyl 4-hydroxybenzoyloxybenzoate Nonyl 4-hydroxybenzoyloxybenzoate Cyclohexyl 4-hydroxybenzoyloxybenzoate -β-Phenethyl 4-hydroxybenzoyloxybenzoate phenyl 4-hydroxybenzoyloxybenzoate α-naphthyl 4-hydroxybenzoyloxybenzoate β-naphthyl 4-hydroxybenzoyloxybenzoate See Butyl bisphenol sulfones (1) Bis-(3-1-butyl-4-hydroxy-6methylphenyl)sulfonebis-(3-ethyl-4-hydroxyphenyl)sulfonebis-(3-propyl-4-hydroxyphenyl)sulfonebis-(3-methyl-4-hydroxy phenyl)sulfonebis-(2-isopropyl-4-hydroxyphenyl)
Sulfonebis-(2-ethyl-4-hydroxyphenyl)sulfonebis=(3-chloro-4-hydroxyphenyl)sulfonebis=(2,3-dimethyl-4-hydroquinphenyl)
Sulfone bis-(2,5-dimethyl-4-hydroxyphenyl)
Sulfonebis-(3-methquin-4-hydroxyphenyl)sulfone4-hydroxyphenyl-2'-ethyl-4'hydroxyphenylsulfone4-hydroxyphenyl-2'-isopropyl4'-
Hydroxyphenylsulfone 4-hydroxyphenyl-3'-isopropyl4'
-Hydroxyphenylsulfone 4-hydroxyphenyl-3'-aecbutyl-4'-
Hydroxyphenylsulfone 3-chloro-4-hydroxyphenyl-3'isopropyl-4' -hydroxyphenylsulfone 2-hydroxy-5-t-butylphenyl-4' -hydroxyphenylsulfone 2-hydroxy-5-t-aminophenyl- 4'-Hydroxyphenylsulfone 2-hydroxy-5-t-isopropylphenyl-4'
-Hydroxyphenylsulfone 2-hydroxy-5-t
-octylphenyl4'-hydroxyphenylsulfonyl-2-hydroquine-5-t-butylphenyl-3'-chloro-4'-hydroxyphenylsulfo2-hydroxy-5-t-butylphenyl-3'-methyl-4' -hydroxyphenylsulfone 2-hydroxy-5-t-butylphenyl-3'-isopropyl-41-hydroxyphenylsulfone 2-hydroxy-5-t-butylphenyl-3'-chloro-4' -hydroxyphenylsulfone 2-hydroxy -5-t-butylphenyl-3'-methyl-4'-hydroxyphenylsulfone2-hydroxy-5-t-butylphenyl-3'-isopropyl-41-hydroxyphenylsulfone2-hydroxy-5-t-butylphenyl -2'-Methyl-4'-hydroxyphenylsulfone 44'-sulfonyldiphenol 24-sulfonyldiphenol 33-dichloro-44'-sulfonyldiphenol 3. 3'-dibromo-4,4'-sulfonyldiphenol 3. 3'55'-Tetrapromol44'-Sulfonyldiphenol 33-diamino-44-sulfonyldiphenol Others p -1eN-Butylphenol 24-Dihydroxybenzophenone Novolak type phenolic resin 4-Hydroxyacetophenone p-phenylphenol Benzyl-4-hydroxyphenylacetate p-Benzylphenol These color developers can be used alone or in combination of two or more.

Furthermore, in the present invention, a polyvalent metal salt of an organic acid can be contained as a stabilizer in order to further improve storage stability such as light resistance, weather resistance, and oil resistance.

Among these stabilizers, the most preferred are those represented by the following general formula (I
V) is a halogen-substituted benzoic acid zinc salt derivative.

[wherein, represents an integer of 1 to 2, and m represents an integer of O to 5. ] In the explanation of the general formula (rV), 0
The 1-C12 alkyl group and the 01-C12 alkoxy group may be linear or branched, and include a methyl group, ethyl group, n-propyl group, isopropyl group,
Examples include n-butyl group, isobutyl group, 1eC-butyl group, hexyl group, octyl group, nonyl group, dotecyl group, methoxy group, ethoxy group, le+l-butoxy group, and the like. As the cycloalkyl group of C-C,o, cyclohexyl group, 2-ethylcyclohexyl group, p-1crt-
Examples include butylcyclohexyl group.

The above stabilizer is a compound having a specific molecular structure selected from among many organic carboxylic acid metal salts. Benzoic acid zinc salts having one or two halogen atoms as substituents on the benzene nucleus have characteristics in light resistance, weather resistance, and oil resistance that are not found in similar organic carboxylic acids or their polyvalent metal salts.

Typical halogen-substituted benzoic acid zinc salt derivatives used in the present invention include the following:
It is not limited to these.

CN I I F +CO2) 2 Z n ■ Zuto C02) 2 Zn Further, as a sensitizer, fatty acid amides such as stearic acid amide and palmitic acid amide, ethylene bisamide,
Montan wax, polyethylene wax, dibenzyl terephthalate, benzyl p-benzyloxybenzoate, diph-lyl carbonate, p-benzylbiphenyl, phenyl α-naphthyl carbonate, 1,4-jethoxynaphthalene, 1-hydroxy-2 -Naphthoic acid phenyl ester, oxalic acid (p-methylbenzyl), β
-benzyloxynaphthalene, 4-biphenyl p-)lyl ether, 1,2-di(3-methylphenoxy)ethane, etc. can also be added.

The binder for the thermosensitive coloring layer has a polymerization degree of 200 to 1.
900 fully saponified polyvinyl alcohol, partially saponified polyvinyl alcohol, carboxy-modified polyvinyl alcohol, amide-modified polyvinyl alcohol, sulfonic acid-modified polyvinyl alcohol, butyral-modified polyvinyl alcohol, other modified polyvinyl alcohols, hydroxyethyl cellulose, methyl cellulose, carboxymethyl cellulose, styrene - maleic anhydride copolymers, styrene-butadiene copolymers and cellulose derivatives such as ethylcellulose, acetylcellulose, polyvinyl chloride, polyvinyl acetate, polyacrylamide, polyacrylic esters, polyvinyl butyral,
Examples include polystyrene and copolymers thereof, polyamide resins, silicone resins, petroleum resins, terpene resins, ketone resins, and coumaron resins. These polymeric substances are used by dissolving them in solvents such as water, alcohols, ketones, esters, and hydrocarbons, or by emulsifying them or dispersing them in paste form in water or other media, depending on the quality required. They can also be used together.

In addition, release agents such as fatty acid metal salts, lubricants such as waxes, benzophenone-based or triazole-based ultraviolet absorbers, water-resistant agents such as glyoxal, dispersants, antifoaming agents, and the like can be used.

The amount of organic color developer and basic colorless dye used in the present invention,
The types and amounts of other various components are determined according to the required performance and recording suitability, and are not particularly limited, but usually 1 to 8 parts of organic color developer per 1 part of basic colorless dye, 1 to 20 parts of filler are used, and binder is suitably 10 to 25% of the total solids content.

By applying a coating liquid consisting of the above adhesive onto the intermediate layer of the present invention, the intended near-infrared light readable thermosensitive recording card can be obtained.

In addition, in order to prevent the recording layer from deteriorating due to water, plasticizers, oil, etc., an overcoat layer made of a polymeric material containing an inorganic or organic filler, an ultraviolet curable resin, or an electron beam curable resin is applied to the recording layer. It is also possible to sequentially laminate thin films such as resin.

The magnetic materials on the back of the card include γ iron oxide, CO iron oxide, and B.
It is also possible to provide a magnetic recording layer using a-ferrite.

The organic color developer, basic colorless dye, and materials to be added as necessary are pulverized to a particle size of several microns or less using a pulverizer such as a ball mill, attritor, or sand grinder, or an appropriate emulsifying device, and then the binder and Depending on the purpose, various additive materials are added to make a coating liquid.

(Function) The near-infrared light reader reads distribution information based on the contrast between the recorded image and the background. This contrast is P
CS (Print Con1+x+t 5iBalj
It is expressed as a value and is determined by the following formula.

The closer the PO2 value is to 1, the clearer the contrast and the higher the reading rate. Therefore, in order to increase the PO2 value, it is necessary to increase the reflection rate (%) of the uncolored area and at the same time lower the reflectance (%) of the recorded area.

The reason why the near-infrared light readable thermosensitive recording card of the present invention has excellent optical readability in the near-infrared region is as follows.

Since the support and intermediate layer of the present invention use a filler that does not absorb light in the near-infrared region of 700 to 120 hm,
Even when near-infrared light passes through the intermediate layer and into the support, the near-infrared light reflectance of the uncolored portion of the heat-sensitive recording layer formed thereon is extremely high.

On the other hand, in the present invention, since the intermediate layer is provided, the coloring composition formed by printing is absorbed and transferred into the intermediate layer, so that the thickness of the coloring composition is significantly thicker than in the case without the intermediate layer. (For this reason, the near-infrared reflectance of the coloring part becomes extremely low. For the above two reasons, the PO2 value becomes extremely close to 1, and misreading will not occur.

(Examples) The present invention will be explained below using Examples and Comparative Examples. In the description, parts indicate parts by weight.

[Example 11 ■A liquid baking tray 40 parts 10% polyvinyl alcohol aqueous solution 32 parts water
20
This composition was mixed and stirred to obtain a dispersion.

■Liquid B 3.6-bis(dimethylamino)fluorene-9spiro-3'-(6'-dimethylamino)phthalide
2.5 parts 10% polyvinyl alcohol aqueous solution 58 parts water
3.1 parts of this composition was ground in a sand mill to an average particle size of 1 μm.

■Liquid C 4.4-isopropylidenediphenol 6.0 parts p-
Zinc chlorbenzoate 4.5 parts 10% polyvinyl alcohol aqueous solution 188 parts water
11.2
This composition was pulverized with a sand mill to an average particle size of 1 μm.

(2) Liquid calcium carbonate (50% dispersion liquid) Each liquid of the above composition was mixed in the following ratio to prepare a recording layer coating liquid.

Solution B: 11.4 parts Solution C: 40.5 parts Liquid: 12.0 parts ■Formation of recording card Solution A was coated with calcium carbonate-containing polyethylene terephthalate film (product name: East Lumirror E62, thickness 250 μm).
The amount of coating after drying on m1 Toshisha) is 3 g/rx! An intermediate layer was formed by coating and drying to form an intermediate layer. Next, on this intermediate layer, the coating liquid for the recording layer was applied in an amount of 6 g/dry after drying.
The surface of the recording layer was treated with a super calender to give a smoothness of 800 to 1000 seconds to obtain a heat-sensitive recording card.

[Example 2] In the preparation of Solution B, 2-chloro-3-methyl- was used instead of 3,6-bis(dimethylamino)fluorene-9-spiro-3'-(6'-dimethylamino)phthalide.
A thermosensitive recording card was obtained in the same manner as in Example 1 except that 6-p-(p-phenylaminophenyl)aminoanilinofluorane was used.

[Example 3] In the preparation of liquid A, amorphous silica was used instead of calcined silica, and in the preparation of liquid B, 36-bis(dimethylamino)fluorene-9-spiro-3'-(6'-dimethyl 3,3-bis-[2
A thermosensitive recording card was obtained in the same manner as in Example 1 except that -(p-dimethylaminophenyl)-2-(p-methoxyphenyl)ethynyl]-4,5,6,7-titrachlorophthalide was used. .

[Comparative Example 1] Each liquid used in Example 1 was mixed in the following proportions to prepare a recording layer coating liquid.

Solution B: 11.4 parts Solution C: 40.5 parts Liquid: 12.0 parts Next, calcium carbonate-containing polyethylene terephthalate film (trade name: Toshi Lumira-E62, thickness 250 μm) was added.
The amount of coating after drying of the above recording layer coating liquid was 6 g/rr! The heat-sensitive recording card of the present invention was obtained by applying the coating and drying to give a smoothness of 800 to 1000 seconds using a supercalender.

[Comparative Example 2] In the preparation of Solution B, 2-chloro-3-methyl- was used instead of 3.6-bis(dimethylamino)fluorene-9-spiro-3'-(6'-dimethylamine)phthalide.
A thermal recording card was obtained in the same manner as in Comparative Example 1 except that 6-p-(p-phenylaminophenyl)aminoanilinofluorane was used.

[Comparative Example 3] In the preparation of Solution B, 3.3-bis[2-(p −
A thermosensitive recording card was obtained in the same manner as in Comparative Example 1 except that tetrachlorophthalide (dimethylaminophenyl)-2(p-methoxyphenyl)ethynyl]-4.5.6.7 was used.

[Comparative Example 4] The same procedure as Comparative Example 1 was carried out, except that a titanium oxide-containing polyethylene terephthalate film (trade name: Niguruma Lemirror E62, thickness 250 μm, manufactured by Toshi Co., Ltd.) was used instead of Toshi Lumirror E62 as a support. A thermosensitive recording card was obtained.

[Comparative Example 5] Instead of Toshi Lumira-262 as a support, a barium sulfate-containing polyethylene terephthalate film (trade name:
A thermosensitive recording card was obtained in the same manner as in Comparative Example 2 except that Melinex 339, thickness 250 μm, manufactured by IC1 Co., Ltd.) was used.

The following quality performance tests were conducted on the heat-sensitive recording cards obtained in the above Examples and Comparative Examples, and the results are shown in Table 1.

Note (1) Dynamic color density, using a 5WEDOT printer, applied voltage 30V, pulse width,
The image density recorded in 6.1 milliseconds was measured using a Macbeth densitometer (R
D-914, using an amber filter).

Note (2) PC8 value: Printing was performed using the method described in Note (1), and the reflectance (%) of the recorded image and background portion was measured using a spectrophotometer at a wavelength of 900 nm, and the PC8 value was calculated.

Note that the PC8 value is the value at 900 nm. This PC3
The value is calculated using the formula below.

(Effects of the Invention) (1) Since the optical readability in the near-infrared region is excellent, misreading does not occur during reading.

(2) Because of its excellent thermal responsiveness, clear high-density images can be obtained even in high-speed, high-density recording.

Procedural amendment (spontaneous) November 10, 1990

Claims (2)

[Claims] (1) In a heat-sensitive recording card in which a heat-sensitive coloring layer containing a colorless or light-colored basic colorless dye and an organic color developer as main components is provided on a support, the support has calcium carbonate applied to a polyester resin. an opaque polyester resin containing 10 to 60% by weight and having a thickness of 100 to 500 μm, the basic colorless dye being at least one type of dye that exhibits a recorded image having absorption in the near red region of 700 to 1200 nm; 70 between the support and the heat-sensitive recording layer
A thermal recording card for near-infrared light reading, comprising an intermediate layer containing an oil-absorbing pigment that has no absorption in the near-infrared region of 0 to 1200 nm. (2) The dye having absorption in the near-infrared region of 700 to 1200 nm is at least one type of compound represented by the following general formula (I), (II) or (III). Heat sensitive recording card. ▲There are mathematical formulas, chemical formulas, tables, etc.▼...(I) [In the formula, R_1, R_2, R_3, R_4, R_5, R_
6 and R_7 are each a hydrogen atom, an alkyl group, an alkoxy group, a cycloalkyl group, a halogen atom, a nitro group,
It represents a hydroxyl group, an amino group, a substituted amino group, an aralkyl group, a substituted aralkyl group, an aryl group, or a substituted aryl group. T_1, T_2 and T_3 are each a hydrogen atom, a C_1 to C_8 alkyl group, a C_3 to C_9 alkenyl group, or a C_3 to C_9 alkynyl group,
T_4 is a hydrogen atom, C_1 to C_8 alkyl group, C_
3 to C_9 alkenyl group, C_3 to C_9 alkynyl group, or phenyl group, and T_3 and T_4 are bonded to adjacent nitrogen atoms to form a monophorino group, pyrrolidino group, piperidino group, or hexamethyleneimino group. Also good. l represents an integer from 0 to 4. ]▲There are mathematical formulas, chemical formulas, tables, etc.▼...(II) [In the formula, R_1_0 is an alkyl group with 8 or less carbon atoms, R_
1_1 represents an alkyl group having 8 or less carbon atoms, a cycloalkyl group having 5 to 7 carbon atoms, a benzyl group or a phenyl group which may have a chlorine atom, bromine atom, or an alkyl group having 4 or less carbon atoms as a substituent. X^1 and X^2 have 8 carbon atoms
Indicates the following alkyl group, alkoxy group having 8 or less carbon atoms, fluorine atom, chlorine atom or bromine atom, where m and n are 0 and 1
, 2 or 3, X^1 comrade of (X^1)_m, (X
^2) _n's X^2 comrades may be the same or different. X^3 represents a chlorine atom or a bromine atom, and both of the four atoms may be present at the same time. ] ▲There are mathematical formulas, chemical formulas, tables, etc.▼...(III) [In the formula, R_1_2, R_1_3, R_1_4, R_1
_5, R_1_6, R_1_7 are each hydrogen atoms; C_1
-C_8 alkyl group; C_5-C_8 cycloalkyl group; C_3-C_8 alkoxyalkyl group; C_3
~C_9 unsaturated alkyl group; tetrahydrofurfuryl group; tetrahydropyran-2-methyl group; halogen atom, C_1 to C_4 alkyl group, alkyl group optionally substituted with C_1 to C_4 alkoxyl group; halogen atom, C_1 to C_4 alkyl group, C_1 to C_4
an aryl group optionally substituted with an alkoxyl group;
Halogen atom, alkyl group of C_1 to C_4; C_1 to
Indicates a C_2 to C_8 alkyl group having a phenoxy group which may be substituted with a C_4 alkoxyl group. Also, R_1_2 and R_1_3, R_1_4 and R_1_5,
R_1_6 and R_1_7 can also form a heterocycle with each other or with an adjacent benzene ring. ]