JPS5926477B2 - thermal recording paper - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a thermal recording paper, and more particularly to a thermal recording paper using 3-diethylamino-7-(2-chloroanilino)fluoran as a coloring agent.

The minimum performance required for a recording layer of thermal recording paper is excellent self-coloring resistance, pressure coloring resistance, heat sensitivity, likelihood resistance, heat decoloring resistance, moisture decoloring resistance, and water resistance. However, we have not yet obtained anything that completely satisfies these requirements.

First, as a method of improving self-coloring resistance,
8-101943 (Japanese Patent Publication No. 51-29830) describes the addition of a water-soluble alkanolamine compound, and JP-A-49-11141 (Japanese Patent Publication No. 51-2823) describes the addition of a basic organic compound. ing.

A method for improving pressure color resistance is disclosed in Japanese Patent Application Laid-open No. 48-3.
No. 0347 and JP-A No. 48-31958 describe the provision of a protective layer such as polyethylene or wax on the surface of the recording layer, and JP-A No. 52-150048 describes the addition of a filler that does not participate in the coloring reaction of the color former. ing.

A method for improving water resistance is disclosed in Japanese Patent Application Laid-Open No. 49-3643.
No., JP-A-49-32646, JP-A-50-3053
No. 9, JP-A-52-145228 and JP-A-53-
No. 13929 and the like describes the use of a water-soluble binder and a waterproofing agent in combination.

A method for improving light resistance is disclosed in Japanese Patent Application Laid-Open No. 49-5404.
Tris (4-hydroxy-
Addition of an inorganic salt of a phenolic compound such as 2,5-di-t-butylphenol) phosphite or the like, or
No. 3205) describes the addition of ultraviolet absorbers such as benzophenone, benzotriazole, and phenyl salicylate compounds.

As a method to improve the heat sensitivity characteristics, there is a method of
No. 48 and Japanese Patent Publication No. 51-39567 describe the combined use of an organic acid and a phenolic compound as an acidic substance, or the use of a polyvalent metal salt of a compound having an alcoholic hydroxyl group.

JP-A-49-11140 (Japanese Patent Publication No. 51-29945) describes the use of a copolymer of hydroxyethyl cellulose and maleic anhydride. Furthermore, JP-A-49-34842, JP-A-49-115554,
JP-A No. 50149353, JP-A No. 52-106746
No., JP-A-53-5636, JP-A-53-11036
Nitrogen-containing compounds such as thioacetanilide, phthalonitrile, acetamide, di-β-naphthyl-p-phenylenediamine, fatty acid amide, acetoacetic acid anilide, diphenylamine, benzamide, carbazole, etc. organic compound or 2,3-
The addition of thermofusible substances such as di-m-tolylbutane, 4,42-dimethylbiphenyl, etc. as sensitizers has been described. A method for improving the fading resistance is to add a phenol resin, which is a condensation product of a phenol compound and an aliphatic aldehyde or an alkyl vinyl ether, to JP-A-48-52245;
-45747 (Special Publication No. 51-43386), 4,
Adding a phenol derivative such as 45-thiobis(6-1-butyl-3-methyl-phenol), and adding a water-insoluble modified phenolic resin such as rosin-modified or terpene-modified resin in JP-A-53-17347. It describes things like that.

Regarding the (3-diethylamino-2-chloroanilino)fluoran used as a coloring agent in the thermal recording paper of the present invention, the manufacturing method thereof and the copying paper using the same are as follows.
JP-A-49-34526 and JP-A-53-, respectively.
No. 25106 exists.

This 3-diethylaminol (2-chloroanilino)
Using a fluoran compound as a coloring agent, thermosensitive recording paper was manufactured according to conventionally known methods and the methods described in the above-mentioned patent publications, and tests were conducted on the performance aspects that a thermosensitive recording paper should have. If you convert the density, it is the background fog density D. On the other hand, the initial color development temperature Ts by heating is high, the temperature coefficient r of the color density curve is small, and the maximum color density Dmax is small. is inferior (・
Ta. For this reason, it is not practical as a thermal recording paper for facsimile machines, especially high-speed facsimile machines. In addition, the skin's light resistance is also poor (i.e., when irradiated with ultraviolet rays using a fade-o-meter tester for 1 hour, the skin becomes sepia-colored, and when irradiated for a further 6 hours, it becomes a slightly darker reddish-brown color, so the color does not develop. The contrast with the coloring agent decreases.Also, if the thermally colored recording paper is left in an atmosphere of 50 to 60 degrees Celsius and 20% relative humidity for 3 to 5 days, the concentration of the coloring agent that produced the color will decrease. It decreased compared to that immediately after. That is, the heat decoloring resistance was low. Furthermore, 50 to 60 ° C.
When left in an atmosphere with a relative humidity of 80 to 90% for 12 to 24 hours, the concentration of the color former will decrease compared to the color concentration immediately after color development, and in some cases, the color will disappear completely and the color will not develop. Even traces of the color former were no longer visible. In other words, the moisture decoloring resistance is low. When thermal recording paper that uses a water-soluble binder as a binder or thermal recording paper that has been colored by heating is immersed in water for a long time, both the uncolored thermal recording layer and the colored thermal recording layer will flow. , or faded. In other words, water resistance is poor. As described above, heat-sensitive recording paper using a 3-diethylamino (2-chloroanilino) fluoran compound as a coloring agent has been inferior in overall practicality. The present inventors have conducted intensive research on thermal recording paper using 3-diethylamino-Jyoroi2-chloroanilino) fluoran compound as a coloring agent, and have found that it has the above-mentioned drawbacks of heat-sensitive properties, light resistance, heat decolorization resistance, and moisture resistance. It has been discovered that a thermosensitive recording paper with excellent practicality can be obtained with dramatically improved color properties, water resistance, humidity resistance, etc.

That is, the combination of a 3-jethylamino (2-chloroanilino) fluoran compound, an acidic substance, a binder, and the general formula (
In the formula, R1 is a hydrogen atom, a hydroxy group or a lower alkyl group.

) and the general formula (wherein R2 is a hydrogen atom or a lower alkyl group).

This is a heat-sensitive recording paper having a recording layer containing one type of compound derived from a 2-(2-hydroxyphenyl)benzotriazole compound represented by Δ. The acidic substance used in the present invention is a substance that is solid at room temperature and can react with a color forming agent when heated. Representative examples thereof include a phenolic compound described in Japanese Patent Publication No. 45-14039, or stearic acid. , benzoic acid, gallic acid, salicylic acid, etc., which have the property of liquefying or vaporizing at 50° C. or higher, or their metal salts such as aluminum and zinc.

Acidic substances that can be suitably used are the above-mentioned phenolic compounds, a typical example of which is 4,4'-isopropylidene diphenol (bisphenol A) compound. A water-soluble or water-insoluble binder is used as the binder for binding the mixture of color former and acidic substance onto the support sheet. Typical examples include polyvinyl alcohol,
Examples include methylcellulose, hydroxyethylcellulose, carboxymethylcellulose, gum arabic, starch, gelatin, casein, polyvinylpyrrolidone, styrene-maleic anhydride copolymer, polyacrylic acid amide, polyacrylate, terpene resin, and petroleum resin. This is a water-soluble binder that can be particularly preferably used in the present invention, and a typical example thereof is polyvinyl alcohol. In order to produce the heat-sensitive recording paper of the present invention, the coloring agent 3
-diethylaminol J yo 2-k C2a anilino) fluoran compound, acidic substance and 2 represented by general formula [1]
-Hydroxybenzophenone compound and general formula []
Each component consisting of one or more compounds selected from 2-(2-hydroxyphenyl)benzotriazole compounds represented by (hereinafter referred to as additive compounds) is uniformly distributed in one heat-sensitive layer as fine particles. A method in which the heat-sensitive recording paper exists in a stable state is preferable in terms of the performance of the thermal recording paper.

Alternatively, each component consisting of a coloring agent and an additive compound exists as fine particles in a uniform state in one layer, and fine particles of an acidic substance exist in a uniform state in close contact with this layer. A method of providing a layer, or a method in which each component consisting of an acidic substance and an additive compound is present in a uniform state as fine particles in one layer, and the fine particles of the coloring agent are brought into close contact with this layer to form a uniform state. In addition, the coloring agent, additive compound, and acidic substance are formed as fine particles.
There is a method in which layers existing in a uniform state among separate layers are brought into close contact with each other. When producing the heat-sensitive recording paper of the present invention, the weight ratio of each of the above-mentioned components and binder in the recording layer to the color former is 0J. -3 times, preferably 0.3-1 times, acidic substances 2-10 times, preferably 4-6 times, and binders 0.

3 to 3 times, preferably 0.

It is 5 to 1 times.

The color former, acidic substance and additive compound are preferably each separately dissolved in water or an organic medium containing the binder using a dispersing machine such as a ball mill, sand mill or paint conditioner. Disperse it using water as a medium and crush it to 1 to 6 μm, preferably 3 μm.
Make a suspension with a particle size of ~5μ.

If necessary, an antifoaming agent, dispersant, or brightener may be added for dispersion and pulverization. Next, a suspension of each of the separately dispersed and pulverized components described above is mixed so that the weight ratio of each component in the recording layer is as described above to prepare a paint for forming a heat-sensitive recording layer.

Apply this paint to the surface of the paper using a wire bar #6 to #10.
A heat-sensitive recording paper is produced by applying the coating so that the weight of the solid after drying is 3 to 77/M2, and drying it in a blow dryer at room temperature to 70°C. If necessary, inorganic or organic fillers may be added to the paint to improve the fusing resistance, writability, etc. of the thermal head. The performance of the recording layer of the thermosensitive recording paper was tested using the following test method. In other words, the self-coloring density, the color density of the coloring agent before and after heating coloring by ultraviolet ray irradiation using a fade-o-meter tester, color change and fading, etc., and the heat or humidity of the coloring agent after heating coloring. The color density of the coloring agent in the sample was measured using a Maghes RD-514 reflection densitometer. Heating coloring was done using a Rodiaceta type thermotest tester (manufactured by the French National Textile Research Institute) at a heating temperature of 80.
~170℃, heating time 3 seconds, load 1007/01ii
It was conducted under the following conditions. Further, decoloring of the coloring agent after coloring by heating was carried out using a constant temperature and humidity tester. The present invention will be specifically explained below using examples, but the present invention is not limited to these examples.

Example 1 (1) 3-diethylaminol (2-chloroanilino) fluoran 47, 20 parts of a 10% by weight polyvinyl alcohol aqueous solution and 20 parts of water were dispersed in a ball mill for 48 hours and pulverized to form a suspension with a particle size of 2 to 3 μm. A liquid A liquid was obtained.

Next, bisphenol A2O7, 20 units of a 10% by weight polyvinyl alcohol aqueous solution and 20 units of water were dispersed in a ball mill for 48 hours and pulverized to form a suspension with a particle size of 2 to 3 μm (Liquid B).
I got it.

Furthermore, 2,4-dihydroxybenzophenone 47,1
0% by weight polyvinyl alcohol aqueous solution 207 and water 1
07 was dispersed in a ball mill for 48 hours and pulverized to a particle size of 2 to 3.
A suspension of μ (liquid C) was obtained.

Liquids A, B and C were mixed, and 10% by weight polyvinyl alcohol aqueous solution 107 was further added and mixed to obtain a thermal paint.

Apply this paint to the surface of high-quality paper using a #10 wire bar.
The coated paper was coated so that the weight of the solid content after drying was 57/M2, and the coated paper was placed in a blow dryer and dried at room temperature to obtain the thermal recording paper (A) of the present invention. (2) 2-hydroxy-benzophenone 17 and 2-hydroxy-5-methylbenzophenone 3
A 710% by weight polyvinyl alcohol aqueous solution 207 and water 107 were dispersed in a ball mill for 48 hours and pulverized to a particle size of 2.
A suspension (solution D) of ~3μ was obtained.

Liquids A, B, and D from (1) above were mixed, and 10 units of a 10% by weight polyvinyl alcohol aqueous solution were added to Δx and mixed to obtain a thermal paint.

Apply this paint to the surface of high-quality paper using #10 wire,
The coated paper was coated so that the weight of the solid content after drying was 57/M2, and the coated paper was placed in a blow dryer and dried at room temperature to obtain a thermal recording paper (b) of the present invention. a The above (1) liquids A and B were mixed, and 10% by weight polyvinyl alcohol aqueous solution 107 was further added and mixed to obtain a thermal paint.

Using this paint, a control thermal recording paper (c) was obtained by processing in the same manner as in (1). 1) 2-Hydroxy-4-methoxybenzophenone 47, 10% by weight polyvinyl alcohol aqueous solution 207 and water 107 were dispersed in a ball mill for 48 hours and pulverized to obtain a suspension with a particle size of 2 to 3 μm (liquid E). .

Liquids A, B, and E were mixed, and 10 units of a 10% by weight polyvinyl alcohol aqueous solution were further added and mixed to obtain a thermal paint.

Using this paint, a control thermal recording paper (d) was obtained by processing in the same manner as in (1). ]) 4-tert-butyl phenyl salicylate 4, 10% by weight polyvinyl alcohol aqueous solution 2
07 and water 107 were dispersed in a ball mill for 48 hours and pulverized to obtain a suspension liquid (liquid F) with a particle size of 2 to 3 μm. Liquids A, B, and F were mixed, and 10 units of a 10% by weight polyvinyl alcohol aqueous solution were further added and mixed to obtain a thermal paint.
Using this paint, a control thermal recording paper (4) was obtained by processing in the same manner as in (1). t) 3-diethylamino-J-anilinofluorane 47, 10% by weight polyvinyl alcohol aqueous solution 20V and water 207 were dispersed in a ball mill for 48 hours and pulverized to obtain a suspension with a particle size of 2 to 3μ (Liquid G). Ta. Liquid G and liquid B of (1) were mixed, and a 10% by weight polyvinyl alcohol aqueous solution 107 was further added and mixed to obtain a thermal paint.

Using this paint, a control thermal recording paper (2) was obtained by processing in the same manner as in (1). Separately, liquid G and liquids B and C of (1) were mixed, and a 10% by weight polyvinyl alcohol aqueous solution 107 was further added and mixed to obtain a thermal paint. Using this paint, a control thermal recording paper (G) was obtained by processing in the same manner as in (1). 7) 4 units of 3-diethylamino-6-methyl-J-anilinofluoran, 20 units of a 10% by weight aqueous polyvinyl alcohol solution, and 20 units of water were dispersed in a ball mill for 48 hours and pulverized to form a suspension with a particle size of 2 to 3 μm. (Liquid H) was obtained.

Solution H and solution B of (1) were mixed, and 10 grams of a 10% by weight polyvinyl alcohol aqueous solution of sea urchin A was added and mixed to obtain a thermal paint.

Using this paint, the same treatment as in (1) was carried out to obtain a control thermal recording paper (No.). Separately, liquid H, liquid B of (1) and CF9
．． 10 parts of a 10% by weight aqueous polyvinyl alcohol solution were further added and mixed to obtain a thermal paint. Using this paint, a control thermosensitive recording paper (Re) was obtained by processing in the same manner as in (1). (8) 4 units of 3-diethylaminol (4-chloro-anilino) fluoran, 20 units of a 10% by weight polyvinyl alcohol aqueous solution and 207 units of water were mixed in a ball mill.
The mixture was dispersed for 8 hours and pulverized to obtain a suspension (liquid I) with a particle size of 2 to 3 μm.

Solution I and Solution B of (1) were mixed, and 10% (!) of a 10% by weight polyvinyl alcohol aqueous solution was added and mixed to obtain a thermal paint.

Using this paint, a control thermal recording paper (b) was obtained by processing in the same manner as in (1). Separately, mix liquid I, liquid B and liquid C,
Furthermore, 10% by weight polypynyl alcohol aqueous solution 107 was added and mixed to obtain a thermal paint. Using this paint (1)
A control thermosensitive recording paper (d) was obtained by processing in the same manner as above. Table 1 shows the results of testing the performance of the recording layer of the heat-sensitive recording papers produced above using the method described above.

Example 2 2-(2-hydroxy-5-methylphenyl)benzotriazole 3, 10% by weight polyvinyl alcohol aqueous solution 207 and water 107 were dispersed in a ball mill for 48 hours and pulverized to form a suspension (J liquid) was obtained.

Mix J solution and A solution, B solution, and C solution of Example 1 (1), and then add 10% by weight polyvinyl alcohol aqueous solution 10
7 was added and mixed to obtain a thermal paint.

This paint was used and treated in the same manner as in Example 1 (1) to obtain a thermal recording paper (4) of the present invention. The performance of the recording layer for this thermosensitive recording was tested in the same manner as in Example 1, and the performance was sufficient for practical use.

That is, the background coloring density was 0.08, the background coloring density was 0J2 after 16 hours of irradiation with a fade-o-meter, and the maximum coloring density when heated was 1J2. Furthermore, the muddy degree at the start of color development, the maximum color development density, and the temperature coefficient of the color development density curve due to heating were 97.5°C, 1.20, and 5.5, respectively.

Claims (1)

[Claims] 1 3-diethylamino-7-(2-chloroanilino)
Fluoran compound, acidic substance, binder, and general formula ▲ Mathematical formula,
There are chemical formulas, tables, etc. ▼ There are 2-hydroxybenzophenone compounds represented by [I] (in the formula, R_1 is a hydrogen atom, hydroxy group, or lower alkyl group) and general formulas ▲ Numerical formulas, chemical formulas, tables, etc. ▼〔II〕
(In the formula, R_2 is a hydrogen atom or a lower alkyl group.) A thermal recording paper characterized by: