JPS5894492A - Recording paper - Google Patents

Abstract

PURPOSE:To provide a recording paper capable of giving a black tone image and excellent in light resistance, water resistance, fastness or the like, by a method wherein a specified fluoran derivative is provided on a base as an electron-donating color former. CONSTITUTION:A fluoran derivative of formula III obtained by bringing a compound of formulaI[wherein R<1> is 1-8C (cyclo)alkyl, 2-8C alkenyl or the like; R<2> is 1-8C alkyl, 2-8C alkenyl, 3-10C alkoxyalkyl or the like; ring A is a benzene or naphthalene ring]and a phenol derivative of formula II (wherein each of X and Y is H, 1-6C alkyl, alkoxy or the like; each of m and n is 1-3; R is H, 1-4C alkyl) into reaction in the presence of a dehydrating condensing agent such as sulfuric acid, is dissolved in a solvent, followed by addition of an acidic substance or the like to produce a coating liquid. For example, an upper- sheet paper obtained by coating with the coating liquid and drying the liquid and a lower-sheet paper obtained by a conventional method are laminated with each other to obtain the objective pressure-sensitive recording paper.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a pressure-sensitive or heat-sensitive recording paper having a support containing a fluorane derivative as an electron-donating coloring agent. More specifically, the present invention relates to the general formula (I) (wherein R1 is an alkyl group having 1 to 8 vertical primes, a cycloalkyl group, a phenylalkyl group whose nucleus may be substituted with alkyl or halogen, and a carbon number 2 -8 alkenyl group, an alkoxyalkyl group or alkoxyalkoxyalkyl group having 8 to 10 carbon atoms, or a phenyl group whose nucleus may be substituted with a halogen or an alkyl group.

R2 is an alkyl group having 1 to 8 carbon atoms, an alkenyl group having 2 to 8 carbon atoms, an alkoxyalkyl group or an alkoxyalkoxyalkyl group having 8 to 10 carbon atoms, or phenylalkyl whose nucleus may be substituted with methyl or halogen. represents a group.

Also, R and R2 together form -(OLlz)p-1-
CH2CH20CH2CEtz +, -CHtCf1
28CH20H2 - where p represents the number 4.5 or 6.

X and Y represent hydrogen, an optionally branched alkyl group having 1 to 6 carbon atoms, an alkoxy group, or a halogen, and m and n represent a number of 1 to 8.

[A represents benzene or naphthalene salt, and may be substituted with halogen. ) is a pressure-sensitive or heat-sensitive recording paper having a fluoran derivative represented by the following as an electron-donating coloring agent on a support.

Pressure-sensitive recording paper and heat-sensitive recording paper, which utilize a coloring reaction caused by contact between an almost uncolored electron-donating substance and an almost uncolored electron-accepting substance, are in high demand with the development of the current information age. is increasing. Generally, pressure-sensitive recording paper is made by dissolving an electrotoxic white dye (hereinafter referred to as a coloring agent) in an organic solvent, emulsifying it to a size of several microns, micro-encapsulating it with a polymer compound such as gelatin, and placing this on a support. It consists of an upper paper coated with an electron-accepting substance (hereinafter referred to as a color developer) and a lower paper coated with an electron-accepting substance (hereinafter referred to as a color developer) on the support. This is a recording method in which the microcapsules are destroyed, the coloring agent in the capsules is released, and the coloring agent is transferred to the surface of the coloring agent, causing a coloring reaction and obtaining a copied image. In addition, in thermal recording paper, a color forming agent and a color developing agent are supported in a binder (for example, a polymeric material such as polyvinyl alcohol) together with a solid flux, if necessary, so that the two do not come into contact with each other. The most common method is a method in which at least one of a fluxing agent, a color former, or a color developer is melted by heating, and the color former and color developer come into contact, causing a coloring reaction to produce a printed image. It is.

In addition, the current-carrying heat-sensitive recording string is produced by providing a conductive layer containing a conductive agent between the support and the color forming layer (containing a color forming agent, a color developer, and a fluxing agent if necessary), and applying a voltage. This is a printing method that generates heat and produces a coloring reaction to obtain a printed image.

In recent years, there has been an increasing demand for color formers that can produce black images due to the need to make copies from 8-pin recording paper that has produced images through the color reaction between the color former and the color developer under pressure or heat as described above. It's here. In principle, black mu@ can be obtained by mixing several suitable coloring agents with different hues, but the coloring speed may vary depending on the type of coloring agent, and the light resistance and water resistance of the image may vary. etc., so there was a drawback that the hue may change depending on the storage condition of the recording paper. In particular, since there is no satisfactory green pigment, which is the main ingredient in the formulation, no pigment has yet been found that produces a black image that is satisfactory in all respects, including hue, fastness, self-coloring, and cost. The current situation is that this is not the case.

The present inventor has discovered that the fluoran derivative represented by the general formula α) is itself a white crystal with no coloration, but when it comes into contact with an acidic substance, it develops a green to dark green to greenish-black color, and has light resistance and
The present invention was completed based on the discovery that the dye has excellent water resistance and strong fastness and is useful as a coloring agent for pressure-sensitive or heat-sensitive recording paper.

Examples of solvents for dissolving the coloring agent in preparing pressure-sensitive recording paper include dichlorobenzene, α-(8°4-dimethylphenyl)-α-phenylethane, methylnaphthalene, propylnaphthalene, butylnaphthalene, benzylbenzoate, 1.4 - Use of dibenzylbenzene, etc. Encapsulation methods include coacervation with gelatin, a method of forming a film from the outer phase, and an interfacial polymerization method that utilizes a film-forming reaction between the inner and outer phases.

Examples of acidic substances include acid clay, activated clay, clays such as attabalgide, resorcinol, novolac-type polymers of one or more phenols such as paraphenylphenol, phenol, cresol, and butylphenol, and benzoin. Examples include metal salts of acids, salicylic acid and its derivatives.

The compound represented by the general formula α) of the present invention is synthesized, for example, as follows.

First, a compound represented by the general formula (II) (wherein R, R and [A have the above-mentioned meanings) and a compound represented by the general formula (Ill) (wherein, X, Y, m, and n are the above-mentioned (where R represents hydrogen or an alkyl group having 1 to 4 carbon atoms.) Using a dehydration condensation agent, -
The reaction is allowed to take place at about 5 to 90°C for several hours to several tens of hours. Next, it is poured into water, and if necessary, the precipitate formed is separated in a furnace, followed by alkali treatment, and further heat treatment if necessary, to obtain slightly colored white crystals. When this is separated, dried, and reconsolidated, the fluoran derivative represented by the general formula α) is obtained as white crystals.The compound represented by the general formula (II) and the general formula (I
Sulfuric acid, phosphoric acid, polyphosphoric acid, etc. are used as the dehydrating agent when synthesizing the compound of general formula α) from the compound of formula α), and 85% to 100% concentration of sulfuric acid is advantageously used.

As the recrystallization solvent, n-hexane, toluene, monochlorobenzene, chloroform, methyl isobutyl ketone, methyl cellosolve, isobutanol, isopropanol, dioxane, ethylene glycol dimethyl ether, etc. are used.

Pressure-sensitive or heat-sensitive recording paper is produced by a conventional method using one or more of the color formers thus obtained, or in combination with other color formers, such as red color formers.

The fluoran derivative represented by the general formula σ) used in the method of the present invention is a compound that is not specifically described in the literature, and exhibits a dark green to greenish-black tone when developed by the color developer described above. Recording paper obtained using this color former is particularly excellent in storage stability, color development, light fastness, and water resistance.

In other words, in pressure-sensitive paper using this coloring agent, the capsule-coated paper has less discoloration due to light, and the light fastness of the colored image is excellent, and in thermal printing, uncolored paper has less discoloration due to temperature and humidity, and It has the great advantage of being less prone to discoloration due to temperature and humidity, and less discoloration or fading due to light. Furthermore, when applied to multicolor thermosensitive recording paper, the color development when heated is clear, multicolor development occurs without color mixing, and it is stable in storage.

The following table shows some examples of fluoran compounds of general formula (I) used in the present invention. Note that the hue indicates the color developed on a thin layer of silica gel.

Next, the present invention will be specifically explained with reference to Examples. In Examples, parts represent parts by weight.

Example 1 2.0 parts of a fluoran compound represented by the above structural formula was added to t
100 parts of x-(8,4-dimethylphenyl)-a-phenylethane, 20 parts of gum arabic, and 160 parts of water.
Add part of the solution and emulsify. 20 parts of acid-treated seratin and 160 parts of water were added thereto, acetic acid was added under constant stirring to adjust the pH to 5, and 50 parts of water was added to advance coacervation. After further adding acetic acid to make p)i 4.4, 4 parts of 87% formalin are added to form a dura mater.

The above operations are performed at 50°C. Next, this system was cooled to 10° C. to promote gelation of the thick liquid film to increase the hardening effect, and after adjusting the pH to 9 by adding an aqueous solution of caustic soda, it was left to stand for several hours to form a capsule emulsion. Next, 80 parts of fine cellulose powder and 100 seconds of an aqueous solution of 10% oxidized starch were mixed with this capsule emulsion, and the mixture was applied to paper and dried.
Create advanced level.

This top sheet was layered with the bottom sheet, and when pressure from a pen or typewriter was applied, a black color developed. That is,
1. A sheet of paper whose surface is coated with a polymer of rose phenylphenol. When using this method, or when using paper whose surface was coated with acid-treated viscous clay, clear dark green characters appeared.

The above-mentioned pressure-sensitive paper had a good shelf life and a fast coloring speed, and the colored characters remained lightless for a long time and did not fade even when wet with water.

Example 2 20 parts of a fluoran compound represented by the above structural formula and 8-
Pressure-sensitive BC was prepared in the same manner as in Example 1 using 0.2 parts of diethylamino-7-methoxyfluorane (red color former).
A recording paper was made.

When printing pressure was applied to this pressure-sensitive paper, it developed a blackish color.

This pressure-sensitive paper had good storage stability, fast color development speed, and excellent light fastness and water resistance of colored characters.

Example 8 30 parts of the fluoran compound represented by the above structural formula was added to 15
Disperse using a sand mill in 0 parts of a 1.0% polyvinyl alcohol water bath solution and 65 parts of water (referred to as component A).

) 85 parts of bisphenol A, 1 part of polyvinyl alcohol
150 parts of 0% water bath liquid is similarly dispersed in 65 parts of water (
It is called component B. ) 3 parts of component A and 67 parts of component B are mixed and applied onto the sheet to a dry weight of approximately 5 Vm2. The sheet thus obtained can be used alone as a thermal paper, and an image with an excellent black edge color can be obtained by a thermal copying machine. Example 4 80 parts of fluoran compound and 8-
A thermal paper was prepared in the same manner as in Example 3 using diethylamino-6,7-benzofluorane (98 parts of a red coloring agent).

This thermal paper did not have self-coloring property, the rate of black coloring was fast, and the light fastness and water resistance of the colored characters were excellent.

Claims (1)

[Scope of Claims] General formula (I) (wherein R1 is an alkyl group having 1 to 8 vertical primes, a cycloalkyl group, a phenylalkyl group whose nucleus may be substituted with alkyl or halogen, and a carbon number of 2 to 8. 8 alkenyl group, an alkoxyalkyl group or alkoxyalkoxyalkyl group having 8 to 10 carbon atoms, or a phenyl group whose nucleus may be substituted with a halogen or an alkyl group. R and R is-together-(CH2)p-1-OH
2GH20CIi2CH2-1-CHzCElz8CH
20H2 - where p represents the number 4.5 or 6. X and Y represent hydrogen, an optionally branched alkyl group having 1 to 6 carbon atoms, an alkoxy group, or a halogen, and m and n represent a number of 1 to 8. fs represents a benzene or naphthalene ring, which may be substituted with halogen. ] A pressure-sensitive or heat-sensitive recording paper having a fluoran derivative represented by the following as an electron-donating coloring agent in a support.