JP2520335B2 - Thermal recording material with excellent chemical resistance and stationery resistance - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention is particularly excellent in chemical resistance and stationery resistance among thermosensitive recording materials comprising a thermosensitive coloring layer using a color reaction between a leuco dye and a color developer on a support. The present invention relates to a thermosensitive recording medium.

[0002]

2. Description of the Related Art Conventionally, basic colorless dyes and phenols,
A heat-sensitive recording material utilizing a heat-coloring reaction with a color developer such as an organic acid is well known. These thermal recording materials are being applied to a wide range of fields such as facsimiles, ticket vending machines, printers such as word processors and personal computers, and automatic teller machines. However, these heat-sensitive recording materials are almost all chemicals including alcohols, esters and ethers, and stationery containing them, such as magic ink, marker,
When an adhesive, mending tape, or the like is used, the color image density may decrease or disappear due to the adhesion of oils and fats such as salad oil, castor oil, and machine oil. Also,
Touching the blank part may cause discoloration or color development. In order to improve these storage stability, 1. One in which an overcoat layer is provided on the color forming layer (see JP-A-62-59081 and JP-A-62-279980). 2. Those that use dyes and developers that have strong chemical resistance and stationery resistance (JP-A-1-29
5882, JP 59-68296, JP 2-2070
(See the official gazette). 3. A pigment-type thermosensitive recording medium, which is a two-component coloring type of an imino compound and an isocyanate compound, has been devised (JP-A-2-103180 and JP-A-2-103181).
(See the official gazette). 4. There are those using a color-developing system using a metal compound (JP-A-62-284782 and JP-A-62-92888).

[0003]

However, the above 1. However, there are drawbacks such that it is difficult to obtain a barrier layer having excellent chemical resistance and stationery resistance, the sensitivity is lowered, and the cost is high. 2. As for the above, there was a problem that excellent chemical resistance and stationery resistance could not be obtained. 3. With respect to (1), excellent chemical resistance and stationery resistance can be obtained, but there are drawbacks that the cost is very high and the color development sensitivity is poor. 3. It is the same chelate type thermosensitive recording medium as the present invention. Also, there was a defect that the color density was low, the background color was colored, and the storage stability of the background color was poor. The present invention has been made in view of the above points, and the purpose thereof is to provide a thermosensitive recording material based on a coloring system using a metal compound, in which the chemical resistance and the stationery resistance of the coloring density are maintained. high,
It is an object of the present invention to provide a heat-sensitive recording material which does not have a ground color and is excellent in storage stability of the ground color.

[0004]

The present invention relates to a thermosensitive recording material comprising a support and a thermosensitive coloring layer using a color reaction between a leuco dye and a color developer, wherein the thermosensitive coloring layer is exposed to water. An insoluble iron behenate, stearyl gallate gallate, leuco dye, 4-hydroxy-4′-isopropoxydiphenyl sulfone, pigment, wax, fluorescent dye, bluish dye, and the above leuco dye and developer 4 -Hydroxy
The particle size of -4'-isopropoxydiphenyl sulfone is
1.5 μm or less, iron behenate, steari gallate
It is a heat-sensitive recording material having a particle size of 4 μm to 7 μm . In the present invention, the leuco dye contained in the thermosensitive coloring layer is not particularly limited, but the following dyes are exemplified. 3- {N- (p-tolylamino)}-7-anilinofluorane, 3- {Np-tolyl) -N-methylamino}
-7-anilinofluorane, 3- {N- (p-tolyl)
-N-ethylamino} -7-anilinofluorane, 3-
{N (p-tolyl) -N-propylamino} -7-anilinofluorane, 3- {N- (p-tolyl) -N-butylamino} -7-anilinofluorane, 3-dimethylamino- 6-methyl-7-anilinofluorane, 3-diethylamino-6-methyl-7-anilinofluorane, 3
-Dipropylamino-6-methyl-7-anilinofluorane, 3-dibutylamino-6-methyl-7-anilinofluorane, 3-pyrrolidino-6-methyl-7-anilinofluorane, 3-piperidino -6-Methyl-7-anilinofluorane, 3-piperazino-6-methyl-7-anilinofluorane, 3-N- (N'-methylpiperazino) -6-methyl-7-anilinofluorane, 3 -Morpholino-6-methyl-7-anilinofluorane, 3-dibenzylamino-6-methyl-7-anilinofluorane, 3- (N-methyl-N-cyclohexyl) -6-methyl-7-ani Rinofluorane, 3- (N-cyclohexylamino) -6-methyl-7-anilinofluorane and the like are used.

Among the leuco dyes exemplified above, 3-dibutylanino-6-methyl-7-anilinofluorane is particularly preferable. Further, the color developing agent used in the present invention is limited to 4-hydroxy-4'isopropoxydiphenyl sulfone. The use ratio of the dye and the developer is not particularly limited, but is generally 0.1 to 50 parts by weight, preferably 1 to 2 parts by weight of the developer, relative to 1 part by weight of the dye. . The use ratio of iron behenate and stearyl gallate used in the present invention is 0.1 to 10 parts by weight, preferably 0.5 to 2.0 parts by weight of stearyl gallate, per 1 part by weight of iron behenate. Is used. Also,
Considering the purpose and effect of the present invention, the use ratio of the leuco dye and developer to iron behenate and stearyl gallate is 10 per 100 parts by weight of the leuco dye and developer.
It is more than 0 parts by weight and preferably 200 parts by weight or more.
It is preferable to use ˜300 parts by weight of iron behenate and stearyl gallate. The coating solution containing these substances is generally prepared by using water as a dispersion medium to form fine particles by a grinding machine such as a ball mill, an attritor or a sand grinder. The leuco dye and the color developer used in the present invention are pulverized to have a particle diameter of 1.5 μm or less. The iron behenate and stearyl gallate are ground to a particle size of 4 to 7 μm. Polyvinyl alcohol, starch, carboxymethyl cellulose, acrylic ester polymer, styrene maleic anhydride copolymer, vinyl acetate maleic anhydride copolymer, styrene butadiene copolymer, casein, as a binder used in the coating liquid, The coating liquid is prepared by blending one or more binders appropriately selected from gelatin and gum arabic. The amount used is 10 based on the total solid content of the coating liquid.
-40 parts by weight, preferably 15-25 parts by weight.

The coating liquid contains talc, calcium carbonate, calcined clay, fine anhydrous silica, aluminum silicate, and aluminum hydroxide for the purpose of preventing the contamination of the thermal head, improving the writability and preventing the coloring of the ground color. Inorganic pigments such as Urea formaldehyde resin and other organic pigments are added. The use ratio is 25 parts by weight or more, preferably 30 to 65 parts by weight, based on 100 parts by weight of the total solid content of the coating liquid. Also, for the purpose of preventing sticking, adjusting recording sensitivity, and the like, paraffin wax, carnauba wax and other animal or plant waxes such as carnauba wax, stearic acid, various soaps, higher fatty acids such as fatty acid amides or derivatives thereof, A wax-like substance such as polyethylene wax, polypropylene wax, or polyethylene glycol is added. It is preferable to add 200 parts by weight or less to 100 parts by weight of iron behenate and gallic acid stearyl ester. In addition, various fluorescent dyes and bluish dyes are added to the coating liquid as auxiliary agents for more effectively preventing background color development (ground color development). The ratio of the fluorescent dye used is 0.15 to 0.025 parts by weight, preferably 0.1 to 0.05 parts by weight, based on 1 part by weight of iron behenate. The ratio of the bluish dye used is 0.006 to 0.0004 parts by weight, preferably 1 part by weight of the fluorescent dye.
0.003 to 0.001 parts by weight are used. In addition, in the coating liquid, if necessary, a triazole-based or benzophenone-based ultraviolet absorber, a waterproofing agent such as glyoxal, a dispersant,
A defoaming agent or the like may be added. As the support, paper, plastic film, synthetic paper or the like is used.

For the purpose of improving whiteness, color development sensitivity, color development uniformity and the like, various precoat layers currently used in heat sensitivity may be provided on these supports. Examples of the pigment used in the precoat layer include organic pigments such as plastic pigments, inorganic carbonates such as calcium carbonate, calcined clay, fine anhydrous silica, aluminum silicate, aluminum hydroxide, talc and kaolin. Examples of the binder include polyvinyl alcohol, starch, water-soluble polyethylene, acrylic resin, styrene-butadiene copolymer and the like. The ratio of the pigment to the binder used is 5 to 100 parts by weight, preferably 10 to 50 parts by weight, based on 100 parts by weight of the pigment. The amount of the precoat layer coated on the support is not particularly limited, but is usually preferably 5 to 10 g / m ^{2 in} terms of solid content. PH of support surface
Is preferably an acidic side where the metal chelate compound is stable. The method for forming the recording layer is not particularly limited, and the recording layer can be formed according to a conventionally known and commonly used technique, for example, air-knife coating, blade coating, bar coating or the like. Apply liquid
It is formed by a drying method or the like. The coating amount of the coating liquid on the support is not particularly limited, but is usually preferably in the range of 3 to 10 g / m ² in terms of solid content.

[0008]

The function of the present invention is 1. Ground color tinting, ground color preservability improvement 1. Improvement of color density 3. The improvement of chemical resistance and stationery resistance will be described. First, 1. For the conventional metal chelate compounds, a combination of iron behenate and stearyl gallate with less ground coloration was selected, and the pulverized particle size was limited to 4 to 7 μm. Contrary to the following cases, the chelate reaction between the two was suppressed, a dye with slow reactivity with gallic acid stearyl ester was selected, and the background color was increased by increasing the ratio of white pigment in the coating liquid. The one with less property was obtained. 2. As a result of taking the measure 1 above, it was possible to use a larger amount of metal chelate compound than the conventional one, and the pulverized particle size of leuco dye and developer was 1.5 μm.
By making the particles finer than m, the color reaction was accelerated and a high color density was obtained. 3. In the conventional leuco dye / metal chelate compound mixture system, a mixture having a metal chelate compound having a higher chemical resistance and stationery resistance than the conventional one was obtained. It was obtained by limiting the leuco dyes and developers that have good chemical resistance.

[0009]

EXAMPLES Examples and comparative examples of the present invention will be described below, but the present invention is not limited thereto. In the following,% and parts represent% by weight and parts by weight, respectively, unless otherwise specified. Example 1 (1) Preparation of Solution A 3-Dibutylanino-6-methyl-7-anilinofluorane 18.5 parts Polyvinyl alcohol 15% aqueous solution 35.3 parts Dispersant 40% aqueous solution 0.5 parts Water 45.7 parts This composition was applied to a sand grinder. -Mean particle size is 0.59μ
crushed to m. (2) Preparation of solution B 4-hydroxy-4'-isopropoxydiphenyl sulfone 33 parts Polyvinyl alcohol 15% aqueous solution 20 parts Dispersant 40% aqueous solution 0.25 parts Water 46.75 parts This composition was used with a sand grinder to give an average particle size of 0.88μ
crushed to m. (3) Preparation of solution C Iron behenate 28.8 parts Paraffin wax 30% aqueous solution 20 parts Polyvinyl alcohol 15% aqueous solution 74.3 parts Water 56.9 parts This composition has a mean particle size of 5.25 μm with a sand grinder.
crushed to m. (4) Preparation of liquid D Stearyl gallate 28.8 parts Paraffin wax 30% aqueous solution 20 parts Polyvinyl alcohol 15% aqueous solution 74.3 parts Water 56.9 parts This composition has a mean particle size of 5.81μ using a sand grinder.
crushed to m. (5) Formation of thermosensitive coloring layer Liquid A 2.6 parts Liquid B 1.4 parts Liquid C 8 parts Liquid D 8 parts Polyvinyl alcohol 10% aqueous solution 5 parts Calcium carbonate 50% dispersion liquid 10 parts Paraffin wax 30% aqueous solution 2.3 parts Fluorescent dye (Note 1) 0.2 parts Blue dye (Note 2) 0.00039 parts Water 17.5 parts (Note 1) Nippon Soda's Kaycoll BXNL (Note 2) Sumitomo Chemical's Patent Pure B
lue VX The coating solution mixed in the above ratio was applied to a high-quality paper of 40 g / m ² of Tsubo Tsubo so that the weight after drying would be 7 g / m ² and subjected to super calendering to obtain a smoothness of 250 seconds. And

Example 2 In Example 1, the average particle size of iron behenate in solution C was 4 μm.
m, the average particle size of gallic acid stearyl ester of liquid D
A thermal recording paper was obtained in the same manner as in Example 1 except that the thickness was 4 μm. Example 3 In Example 1, the amount of iron behenate in solution C was 8 to 4 parts and the amount of stearyl gallate in solution D was 8 to 4 parts.
A thermosensitive recording paper was obtained in the same manner as in Example 1 except that the parts were used. Example 4 (1) Formation of precoat layer Calcium carbonate 50% dispersion 57.4 parts Polyvinyl alcohol 20% aqueous solution 31.5 parts Water 11.1 parts The coating liquid mixed in the above proportions was dried on 40 g / m ² high-quality paper. Example 1 except that the subsequent weight was 10 g / m ^2.
In the same manner as described above, a thermosensitive recording paper was obtained. Example 5 In Example 1, 3-dibutylanino-6-methyl-7-anilinofluorane of the solution A was replaced with {2-anilino-6-.
A thermal recording paper was obtained in the same manner as in Example 1 except that (N-ethyl-N-isopentylamino) -3-methyl} xanthene-9-spiro-1 '-(3'isobenzofuranone) was used. Example 6 Except that in Example 1, 3-N-methyl-N-cyclohexylamino-6-methyl-7-anilinofluorane was used as the liquid A, 3-dibutylanino-6-methyl-7-anilinofluorane. A thermal recording paper was obtained in the same manner as in Example 1.

Comparative Example 1 A thermosensitive recording paper was obtained in the same manner as in Example 1 except that propyl gallate was used in place of the stearyl ester gallate in the liquid D. Comparative Example 2 In Example 1, the average particle size of iron behenate in solution C was 3 μm.
m, D is the average particle size of gallic acid stearyl ester
A thermal recording paper was obtained in the same manner as in Example 1 except that the thickness was 2 μm. Comparative Example 3 In Example 1, the average particle size of iron behenate in the C liquid was 3 μm.
m, D liquid and the average particle size of gallic acid stearyl ester
A thermal recording paper was obtained in the same manner as in Example 1 except that the thickness was 0.8 μm. Comparative Example 4 A thermosensitive recording paper was obtained in the same manner as in Example 1 except that the amount of calcium carbonate was changed from 10 parts to 5 parts. Comparative Example 5 A thermosensitive recording paper was obtained in the same manner as in Example 1 except that the amount of calcium carbonate was changed from 10 parts to 2 parts.

Comparative Example 6 A thermosensitive recording paper was obtained in the same manner as in Example 1 except that the solutions A and B were removed. Comparative Example 7 A thermosensitive recording paper was obtained in the same manner as in Example 1 except that the solution B was removed. Comparative Example 8 A thermosensitive recording paper was obtained in the same manner as in Example 1 except that bisphenol A was used instead of 4-hydroxy-4′-isopropoxydiphenyl sulfone in the liquid B. Comparative Example 9 A thermal recording paper was obtained in the same manner as in Example 1 except that the fluorescent dye and the bluish dye were removed. Comparative Example 10 A thermosensitive recording paper was obtained in the same manner as in Example 1 except that the blue dye was removed. Comparative Example 11 In Example 1, the amount of A solution and B solution taken was from 8 parts to 1.5.
A thermosensitive recording paper was obtained in the same manner as in Example 1 except that the parts were used.

[0013]

[Table 1] ○ can be read unconditionally. △ can be read under certain conditions. × is not legible.

Physical properties were evaluated using the following test methods. [Test Method] Whiteness: Measured with a Hunter-Whiteness Meter manufactured by Toyo Seiki Seisakusho. Ground color Measured with a reflection densitometer (DM-400) manufactured by Dainippon Screen Mfg. Co., Ltd. Color Sensitivity The color density was measured at the high energy part of the Toshiba Wopro Rupo 90HX. Static color development The color density was measured by pressing with a thermal gradient tester manufactured by Toyo Seiki Seisakusho under the conditions of 70 ° C. and 0.8 kg / cm ^{2 for} 5 seconds. Light resistance It was processed for 24 hours with a 5000Lux fluorescent lamp and the background color was measured. Moisture resistance It was processed under the conditions of 40 ° C and 90% RH for 48 hours, and the ground color part was measured. Heat resistance was treated under the condition of 60 ° C for 48 hours, and the ground color part was measured. Water resistance After immersing in tap water at 20 ° C for 24 hours, the fading property of the printed part was visually evaluated. Saline resistance After dipping in saturated saline at 20 ° C for 24 hours, the fading of the printed part was evaluated visually. Alcohol resistance After dipping in sake at 20 ° C for 24 hours, the fading property of the printed part was visually evaluated. Corrosion resistance to vinegar After dipping in Mitsukan vinegar at 20 ° C for 24 hours, the fading property of the printed part was visually evaluated. Ethanol resistance After dipping for 15 minutes with a first grade reagent manufactured by Wako Pure Chemical Industries, the discoloration of the printed part was visually evaluated. Lap resistance Mitsubishi Aluminum Co., Ltd. Diamond wrap is wrapped in a cylindrical container in 2-3 layers, and the sample is wrapped in 2-3 layers. After processing at 40 ° C and 90% RH for 24 hours, printing The fading property of the part was visually evaluated. Diazo resistance Amine phenomenon The photosensitive paper was passed through a phenomenon roll twice, immediately after being adhered and treated for 10 minutes, and the background color fog was visually evaluated. Pencil Writability Written with Mitsubishi Pencil HB, the writability was evaluated. Slow-lighting liquid resistance After applying a removing solution manufactured by Fullvale Co. with a cotton swab, the fading property of the printed part was visually evaluated. Magic resistance After drawing with an oil-based magic ink manufactured by Zebra, the fading property of the printed part was visually evaluated. Resistance to highlighter pen After drawing with a highlighter manufactured by Pilot, the fading property of the printed part was visually evaluated. Vermilion resistance After stamping with vermilion meat manufactured by KOKUYO, the fading property of the printed part was visually evaluated. Stick paste resistance After applying a stick glue manufactured by Dragonfly Co., Ltd., the fading property of the printed portion was visually evaluated. Mending resistance After applying a Yamato Mending Tape, the tape was left for one month and the discoloration of the printed part was visually evaluated.

[0015]

As can be seen from the above description, the present invention uses a combination of iron behenate and gallic acid stearyl ester, which have less ground coloration, among the metal chelate compounds, and their pulverized particle size. Of 4 to 7 μm to suppress the chelate reaction between the two, and to select a dye with slow reactivity with gallic acid stearyl ester, and to increase the ratio of white pigment in the coating liquid A product having little color tinting property was obtained, and the preservability of the background color was improved.
In addition, it was possible to use a larger amount of metal chelate compound than the conventional one, and by making the pulverized particle size of the leuco dye and the developer finer to 1.5 μm or less, the color development reaction was promoted and A high price was obtained. Then, in the conventional leuco dye / metal chelate compound mixture system, the mixing ratio of the metal chelate compound which improves the chemical resistance and stationery resistance is made higher than that of the conventional leuco dye. Since the color developer is limited to those having good chemical resistance, the chemical resistance and stationery resistance are improved.

[Table 1]

[Table 1]

[Table 1]

Claims (3)

(57) [Claims] 1. A thermosensitive recording medium comprising a support and a thermosensitive coloring layer formed by using a color reaction between a leuco dye and a color developer, wherein the thermosensitive coloring layer contains iron behenate, gallic acid stearyl ester, Leuco dye, 4-hydroxy-4'-isopropoxydiphenyl sulfone, pigment, wax, fluorescent dye,
Contains a bluish dye and is a leuco dye and a developer 4
-Hydroxy-4'-isopropoxydiphenylsulfo
Particle size of 1.5μm or less, iron behenate, erosion
Particle size of stearic acid stearyl ester is 4 μm to 7 μm
Chemical resistance,耐文device excellent in heat-sensitive recording material, characterized in that that. 2. Iron behenate and 100 gallic acid stearyl ester based on 100 parts by weight of the leuco dye and the color developer.
Chemical resistance according to claim 1 Symbol mounting, characterized in that contained parts of more than parts by weight,耐文device excellent in heat-sensitive recording material. Wherein said support is chemically resistant according to claim 1 or 2, characterized in that it is acidic paper or acidic precoat paper,耐文device excellent in heat-sensitive recording material.