JPH0377071B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a heat-sensitive or pressure-sensitive recording material, in which a recording material can be formed by thermal printing using a thermal head, and a recorded image can also be formed by local pressure from a typewriter, computer output printer, etc. related to the recording materials to be used. In recent years, with the increase in the amount of information, and social demands such as resource saving, labor saving, and non-pollution, various recording methods have been put into practical use and improved in the information recording field. Pressure sensitive recording materials are widespread. This is because the thermal recording method () produces primary color and does not require a developing process, () the hardware can be made simple and compact, and maintenance costs are low; () it feels close to plain paper, and the sheet itself is relatively inexpensive. Because of these features, it has been put to practical use in computer output, medical measurement recorders, low-speed or medium-speed facsimiles, calculators and other printers, automatic ticket vending machines, thermal copying, etc. These features and fields of application are the same in the pressure-sensitive recording type (however, the pressure-sensitive copying field is used instead of the thermal copying field). The heat-sensitive recording material used in such a method includes a heat-sensitive coloring layer containing a colorless or light-colored leuco dye having a lactone, lactam, or spiropyra ring and an acidic substance (e.g., an organic acid, a phenolic compound) on a support. Established (Special Public Interest Publication 43-4160)
No. 45-14039, etc.) are publicly known. On the other hand, as a pressure-sensitive recording material, among the above-mentioned leuco dyes, those having instantaneous color development (for example, crystal violet lactone, malachite green lactone, rhodamine-β-lactam, etc.) are encapsulated. However, this main heat-sensitive recording material (or
Pressure-sensitive recording materials (pressure-sensitive recording materials) are not only colored by heating or pressure; they are also colored by organic solvents, and colored images are also erased by plasticizers contained in resin films. There is a flaw. That is, in the latter case, this heat-sensitive (pressure-sensitive) recording material has a clear image at the beginning of recording, but when it is used as a ticket (pass, commuter pass, commuter pass, etc.), the wallet... When stored for 3 or 6 months in a commuter pass, etc., the record (image) of the colored part will be transferred to the heat-sensitive or pressure-sensitive color layer of the plasticizer (dioctyl phthalate, dioctyl adipate, etc.) contained in the transparent resin film of the commuter pass. This is thought to be due to the penetration of Furthermore, colored images have the disadvantage that they are also erased by the developer of semi-dry diazo copying machines, which often causes problems in practical use. The inventors of the present invention have conducted extensive research and studies with the aim of solving the above-mentioned drawbacks and inconveniences, and have found that a metal salt of salicylaldoxime is blended into the heat-sensitive coloring layer or the pressure-sensitive coloring layer. It was found that good results could be obtained if The present invention was completed based on this knowledge. Therefore, the heat-sensitive (or pressure-sensitive) recording material of the present invention has a colorless or light-colored leuco dye on a support, a color developer that reacts with the leuco dye when heated (or pressurized) to develop a color, and a salicyl It is characterized by being provided with a heat-sensitive layer (or pressure-sensitive layer) mainly composed of an aldoxime metal salt compound. As mentioned above, in the pressure-sensitive recording material, the leuco dye is encapsulated by known means. Usually colorless or light-colored leuco dyes used in the present invention include triphenylmethane-based, fluoran-based,
These are leuco dyes such as phenothiazine, auramine, and spiropyran, and a representative example of these is 3,3-bis(p-dimethylaminophenyl).
-6-dimethylaminophthalide (also known as crystal violet lactone) 3,3-bis(p-dimethylaminophenyl)
Phthalide 3,3-bis(p-dimethylaminophenyl)
-6-diethylaminophthalide 3,3-bis(p-dimethylaminophenyl)
-6-chlorophthalide 3-(N-p-tolyl-N-ethylamino)-6
-Methyl-7-(N-phenylamino)fluoran 3-diethylamino-7-chlorofluoran Benzoylleucomethylene blue 6'-chloro-8'-methoxy-benzoindolinopyrillospiran 6'-bromo-8'-methoxy-benzoin Dolinopyrillospiran 2-[3,6-bis(diethylamino)-9-
Examples include (o-chloroanilino)xantyl]benzoic acid lactam. A color developer (for example, an organic acid, a phenolic compound) that causes the leuco dye to develop color by reacting with heat or by reacting with the ruptured capsule of the leuco dye is usually combined with the leuco dye. For example, benzoic acid, salicylic acid, tartaric acid, gallic acid, α-naphthol, β-naphthol, 4-tert-butylphenol, 4-tert-octylphenol, 4-phenylphenol can be used. ,
2,2-bis(p-hydroxyphenyl)propane, 2,2-bis(p-hydroxyphenyl)butane, 4,4'-dichlorohexylidene diphenol, 2,2-bis(2,5-dibromo- 4-hydroxyphenyl)propane, 4,4'-isopropylidene bis(2-tert-butylphenol), 2,
2'-methylenebis(4-chlorophenol), p
Typical examples include -oxybenzoic acid, propyl p-oxybenzoate, phenyl p-oxybenzoate, benzine p-oxybenzoate, propyl gallate, octyl gallate, and stearyl gallate. In addition, the metals of the metal salt compound of salicylaldoxime used in the present invention include calcium, barium, magnesium, aluminum, tin,
Examples include iron, cobalt, nickel, copper, zinc, etc., and particularly preferred metals are zinc, aluminum, tin, and magnesium. Although it is desirable that the metal salt compound of salicylaldoxime be uncolored, a colored one may be effective for special purposes. Although there has been no detailed study as to why the metal salt compound of salicylaldoxime produces better results when used in combination with leuco dyes and color developers, it is likely that the metal somehow contributes to the stabilization of the color dye. This seems to be because In order to actually produce the heat-sensitive recording material of the present invention, the above-mentioned leuco dye, color developer, and metal salt compound of salicylaldoxime are used together with a binder and a support (paper, synthetic paper, synthetic resin film, metal laminated paper, etc.). It may be provided as a heat-sensitive coloring layer. Widely known binders are used here, but specific examples include polyvinyl alcohol, methoxycellulose, hydroxycellulose, carboxymethylcellulose, carboxyethylcellulose, polyvinylpyrrolidone, polyacrylamide, polyacrylic acid, starch, gelatin, etc. can be given. In addition, in combination with these water-soluble binders, for example, styrene-butadiene copolymer, vinyl chloride-vinyl acetate copolymer, polyvinyl acetate, polyacrylic acid ester, polymethacrylic acid ester such as polybutyl methacrylate, etc. latexes can also be used. The clarity of the colored image can be improved by adding fine powders such as silica, magnesium, talc, calcium carbonate, barium sulfate, aluminum stearate, urea-holimain resin, and styrene resin to the heat-sensitive coloring layer. is desirable. In addition, when coating and forming a heat-sensitive coloring layer on a support, dispersion aids, antifoaming agents, wetting agents, viscosity modifiers, waxes, etc. are added to the heat-sensitive coloring layer forming liquid to improve coating properties and thermal response. Furthermore, by adding ultraviolet absorbers, antioxidants, etc., it is possible to improve the weather resistance and oxidation resistance of colored images and background areas. The amount of fixed matter adhered to the heat-sensitive coloring layer is suitably about 1.0 to 10 g/m ² . In addition, the amount of leuco dye in the heat-sensitive coloring layer is 10 to 15% by weight, and the amount of color developer is 20 to 80% by weight.
Appropriately, the amount of the metal salt compound of salicylaldoxime is about 10 to 80 percent by weight, and the amount of the binder is about 5 to 30 percent by weight. On the other hand, in order to actually produce a pressure-sensitive recording material, a layer containing a color developer as a main phase is provided on a support, and a layer containing an encapsulated leuco dye as a main phase is provided on top of the layer. A salicylaldoxime metal salt compound is added to either or both of the above layers. Gelatin is commonly used in capsules.
Further, the above-mentioned binders are used to form these layers, and the mixing ratio of each component is almost the same as that of the heat-sensitive recording material, and the above-mentioned additives may also be used as appropriate. However, when it comes to pressure-sensitive recording materials,
It is beneficial to add trace amounts of fluorescent whitening dyes to improve lightfastness. The amount of solid content deposited in the layer mainly composed of a color developer is 2 to 7 g/m ² , and the amount of solid content deposited in a layer mainly composed of leuco dye is 2 to 10 g/m ² . According to the heat-sensitive or pressure-sensitive recording material thus obtained, the objects of the present invention can be fully achieved. Next, examples and comparative examples will be shown. Note that all parts here are parts by weight. First, a mixture consisting of the following compositions was pulverized and dispersed in a magnetic ball mill for 24 hours to form liquid A, liquid B,
Solution C and solution D were prepared. (Liquid A) 2-{N-(3'-trifluoromethylphenylamino)}-6-diethylaminofluorane 75 parts 5% polyvinyl alcohol aqueous solution 75 parts Water 200 parts (Liquid B) 2,2-bis(p -Hydroxyphenyl)propane 120 parts 5% polyvinyl alcohol aqueous solution 120 parts Water 160 parts (liquid C) Calcium carbonate (average particle size 1-2 μm) 150 parts Methylcellulose 5% aqueous solution 300 parts 2,6-diisopropylnaphthalene 150 parts Water 800 Part (Liquid D) Salicylaldoxime metal salt compound 120 parts 5% polyvinyl alcohol aqueous solution 120 parts Water 160 parts Examples 1 to 3 10 parts of the above-mentioned liquid A, 10 parts of liquid C, and 10 parts of liquid D were mixed. Apply it on the surface of high-quality paper (standard basis weight 53g/m ² ) with a wire bar, dry at 50℃,
A thermosensitive recording material was obtained by forming a thermosensitive coloring layer of g/m ² . Examples 4 to 6 10 parts of liquid A, 5 parts of liquid B, 10 parts of liquid C, and 5 parts of liquid D
53 g/m ² of standard basis weight)
A heat-sensitive recording material was obtained by coating the surface of the film with a wire bar and drying at 50°C to form a heat-sensitive coloring layer with a weight of 6 to 7 g/m ² . Comparative Example A comparative heat-sensitive recording material was obtained in exactly the same manner as in Example 1, except that a heat-sensitive coloring layer forming liquid prepared by mixing 10 parts of liquid A, 10 parts of liquid B, and 10 parts of liquid C was used. Each of the heat-sensitive recording materials prepared as described above was calendered so that the smoothness of the heat-sensitive coloring layer was 150 to 250 seconds in terms of Beck smoothness, and then heated using a thermal gradient tester (manufactured by Toyo Seiki KK). Using
Printing was carried out by contacting for 1 second at a temperature of 120° C. and a pressure of 2.0 Kg/cm ² . The print density and background density of each heat-sensitive recording material were measured using a Macbeth densitometer. The results of these measurements are shown in Table-1.

[Table] Examples 7-8 Microcapsules containing colorless dyes were prepared from gelatin-gum arabic capsules (average particle size approx. 5 μm) was adjusted. This dispersion was applied to general high-quality paper (53 g/m ² ) with a solid content of approximately 5.
A dye sheet was prepared by coating and drying to give a dye sheet of g/m ² . Meanwhile, 10 parts salicylaldoxime metal (zinc, aluminum) salt and 10 parts polyvinyl alcohol
A developer sheet was prepared by applying a dispersion containing 5 parts of a % aqueous solution to a high-quality paper (53 g/m ^{2 ) so that the solid content was about 5 g/m 2 and} drying it. These two sheets were then stacked and drawn with a pressure pen, resulting in a bright blue image. Moreover, the results of these measurements were as shown in Table-2. Comparative Example 2 A dye sheet was prepared in the same manner as in Example 7,
The color developer sheet was prepared in the same manner except that activated clay was used instead of the salicylaldoxime metal salt. The measurement results were as shown in Table 2.

[Table] Same as above.

Claims (1)

[Claims] 1. A recording layer containing as main components a colorless or light-colored leuco dye, a color developer that develops color by reacting with the leuco dye when heated or pressurized, and a metal salt compound of salicylaldoxime is provided on a support. Recording material characterized by being