JPH0353980A - Color forming recording material - Google Patents

Abstract

PURPOSE:To obtain a recording material, wherein fluorane chromogenes usable even independently or as compounding toning ones are combined, having excellent color forming characteristics and fading characteristics by combining a specific fluorane derivative with a color forming material containing a salicylic acid skeletal in its molecule as a color forming chromogen. CONSTITUTION:A fluorane derivative represented by formula I (wherein R1 and R2 may be same or different and are an alkyl group or a cycloalkyl group and R3 is am m-chlorophenyl group, a 2-methyl-4-chlorophenyl group, a 4- methyl-2-chlorophenyl group, a 3,5-dichlorophenyl group, a 3,4-dichlorophenyl group, a 2,4-dichlorophenyl group, a 3-chloro-4-methylphenyl group or a 4- chloro-3-methylphenyl group) is combined with a coupler material containing a salicylic acid derivative skeletal in its molecule as a chromogen. By this method, the fluorane derivative develops excellent color forming effect to the coupler containing the salicylic acid skeletal in its molecule as a color forming recording material.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a color-forming recording material comprising a combination of a fluorane-based color-forming chromogen and a salicylic acid-based color developer. More specifically, general formula (1) (wherein R1 and R2 may be the same or different and represent an alkyl group or a cycloalkyl group, and R3 is m-chlorophenyl, 2-methyl-4
-chlorophenyl, 4-methyl-2-chlorophenyl,
3.5-dichlorophenyl, 3.4-dichlorophenyl, 24-dichlorophenyl, 3-chloro-4-methylphenyl or 4-chloro-3-methylphenyl group). The present invention relates to a color-developing recording material comprising a combination of a color-developing chromogen and a color-developing material containing a salicylic acid skeleton in its molecule.

The recording material of the present invention is an information recording material known as a pressure-sensitive or heat-sensitive recording material.

[Conventional technology]

Fluoran derivatives having the following structure are known as black color-forming colorless leuco dyes that have been conventionally used in pressure-sensitive or heat-sensitive recording materials.

(Here, R and R2 represent an alkyl group, a cycloalkyl group, or a phenyl group). These compounds have the problem that either they are useful chromogens or their combinations are not common because they have a methyl group at the 6-position, and are therefore expensive.

On the other hand, in recent years, color developers containing a salicylic acid skeleton in the molecule have come to be widely used in the field of pressure-sensitive copying paper, and when a fluoran derivative with the above structure is applied to this type of color developer,
Unlike when applied to activated clay-based or phenolic resin-based color developers, the hue is not pure black but rather biased toward reddishness, and therefore, for correction, a leuco dye with a coloring hue or green must be used in combination. On the other hand, known compounds with different coloring hues have different structures and therefore have different coloring characteristics, and also have different temporal changes and fading characteristics of colored images. However, when these are used in combination, compared to when a single dye is used, there is a problem in that the hue changes during color development or fading. In particular, green color-forming compounds are problematic because the light fastness of colored images is generally inferior to that of black color-forming compounds.

(Problems to be Solved by the Invention) The objects of the present invention are: (1) a color developer containing a salicylic acid skeleton in its molecule; It is an object of the present invention to provide a recording material that is combined with a fluoran chromogen that can also be used for blending and toning.

(Means for Solving the Problems) The present inventors have made extensive studies to solve the above-mentioned problems. That is, as a result of various studies on various fluoran derivatives, it was surprisingly found that a fluoran derivative without a methyl group at the 6-position of the following formula 4 was used as a color-forming recording material for a color developer containing a salicylic acid skeleton in its molecule. The present invention was completed based on the discovery that the present invention has excellent effects.

That is, the present invention relates to the general formula (1) (wherein R1 and R2 may be the same or different and represent an alkyl group or a cycloalkyl group, R3ham-chlorophenyl, 2-methyl-4-chlorophenyl, 4-
Methyl-2-chlorophenyl, . 3. 5-fluoran derivatives represented by 5-cyclophenyl, 3,4-cyclophenyl, 2,4-dichlorophenyl, 3-chloro-4-methylphenyl, or 4-chloro-3-methylphenyl) This is a color-developing recording material characterized by being composed of a chromogen in combination with a color-developing material containing a salicylic acid skeleton in its molecule.

The fluoran derivative of the general formula (1) used in the present invention is synthesized with a compound according to the following formula.

The fluoran derivative represented by the general formula (I), which exhibits excellent color-forming performance in combination with a color-developing material containing a salicylic acid skeleton in the molecule, is not only a known compound, but also a synthetic compound for the first time by the present inventors. Also included are novel fluorane derivatives.

Table 1 lists examples of fluoran derivatives that can be applied to the recording material of the present invention, including such novel fluoran derivatives.

The structures and melting points of exemplary compounds used in the present invention are shown in Table 1.

The structures shown in Table 1 are the structures represented by general formula (I) in which Rl, R2, . 'R3 is shown in the following table.

Table 1 There are commercially available products.

For example, when the fluoran derivative represented by the general formula (I) used in the present invention is used as a pressure-sensitive recording paper, the dye may be alkylhenzene (such as n-dodecylhenzene), alkylbiphenyl (such as triethylbiphenyl and noisopropylcyphenyl), hydrogenated terphenyls, alkylnaphthalenes (such as cyisopropylnaphthalene), and arylethanes (phenylxylylethane,
gelatin, melamine-aldehyde or urea-aldehyde resin. The aqueous dispersion of the obtained capsules is encapsulated in microcapsules having partition walls made of polyurethane, polyurea, polyamide, etc., and placed on a suitable support together with a suitable binder (for example, starch paste, latex, etc.). It can be coated and used as pressure-sensitive recording paper. In addition, as the color developer used in the present invention, a copolymer of salicylic acid and aldehydes of phenols, substituted salicylic acid or a metal salt thereof (for example, 3,5-c-α-phenethylsalicylic acid zinc salt), or an aralkylated Examples include zinc-modified resins made by condensing salicylic acid with styrene oligomers. These color developers are micronized and added with appropriate pigments, stabilizers,
A coating liquid mixed with a binder and the like is prepared, and this coating liquid is applied onto a suitable support to be used as pressure-sensitive recording paper. Furthermore, it can be similarly used for pressure-sensitive recording materials of a non-capsule type.

In addition, when applying the fluoran derivative of the general formula (I) to a heat-sensitive recording material, a binder (for example, polyhinyl alcohol, methyl cellulose, hydroxyethyl cellulose, carpoquin methyl cellulose, , arahia gum, styrene-maleic anhydride copolymer, etc.), pigments (talc, kaolin, lime carbonate, etc.), sensitizers (higher fatty acid amides, esters of aromatic carboxylic acids or sulfonic acids, aromatic or aromatic substituted Other additives (such as aliphatic ethers, aromatic or aromatic-substituted aliphatic hydrocarbons, etc.) may be added to form a fine dispersion, which can be coated on a suitable support and used as a heat-sensitive recording material.

(Examples) Hereinafter, the present invention will be explained in detail with reference to Examples, but the present invention is not limited thereto.

In addition, parts in the text mean parts by weight.

Example 1 Comparison of pressure-sensitive recording paper using a zinc salt of a condensed resin of phenethyl group-substituted salicylic acid and styrene oligomer as a developer and pressure-sensitive recording paper using a phenylphenol nopolanoch resin as a developer (1) Creation of upper (CB) sheet and lower (CF) sheet + a + CB sheet 10% aqueous solution of ethylene-maleic anhydride copolymer 10
0 parts and 240 parts of water were combined, and 10 parts of sodium hydroxide was added.
% aqueous solution to pH 4.0, mixed with 200 parts of a phenylxylylethane solution containing 5% by weight of the pigment to be evaluated, and emulsified with a homomixer. Chemical “Euramin T-3”
0J) was added and kept at 55°C for 3 hours while stirring to obtain a microcapsule dispersion with an average particle size of 5.0μ. To 100 parts of this microcapsule liquid, 20 parts of wheat flour starch granules, 20 parts of 20% oxidized starch paste, and 116 parts of water are added and dispersed by stirring to give a coating amount or solid content of 5 g/m2 to paper with a basis weight of 40 g/m2. A CB sheet was obtained by coating as follows.

fblcF sheet (A) Zinc salt of resin obtained by condensation of α-phenethyl group-substituted salicylic acid and styrene oligomer is atomized using a sand 1 1 grinding mill in water in the presence of a small amount of polymeric anionic surfactant to form a solid. A 40% by weight aqueous suspension was obtained. A water-based paint (solid content: 30%) with the following composition was prepared using the water-based suspension, and applied to high-quality paper with a basis weight of 40 g/m2 at a dry coating weight of 5.5 g/m'. , created CF sort.

Water-based paint composition Solid weight part Soft calcium carbonate 100 Color developer
20 Adhesive Oxidized starch powder 8 Synthetic latex 8 (CICF sheet (B) C in the same manner using p-phenylphenol-formaldehyde cocondensation resin instead of the salicylic acid resin in (A).
F sheet (B) was created.

(2) Performance evaluation of colored products (a) Color development speed and density (conducted in a constant temperature and humidity room at 20°C and 65% RH) The coated surfaces of the CF sheet and CB sheet were stacked facing each other, and the electronic type I colored it by applying pressure with a lighter. Keystroke 1
The color was measured at two points, one after 30 minutes and 24 hours, and expressed as a Y value.

A CF sheet colored with the light fastness l of the fbl color image was exposed for 2 hours and 4 hours in a carbon arc fade-ometer (manufactured by Suga Test Instruments Co., Ltd.), and the reflectance after irradiation was measured using a Σ-80 color difference meter. (manufactured by Nippon Denshokusha) and expressed as a Y value. The lower the Y value and the smaller the difference Δ value between the values before and after the test, the less the color fades due to light. Also, the lower the Y value, the higher the density of the colored image.

The evaluation results for CF paper (A) are shown in the following table.

No. CF paper Coloring hue (A) Greenish black / Same as above! / Same as above Reddish black // Greenish black / L Dark Initial green coloring density Final image light fastness 2hrs 4hrs 61 5 60 9 60 4 61. 1 60 7 59 3 61. 0 59.7 65 1. 74 7△5.4
△15.0 59.0 64.3 74 5△5 3 △
l5.5 58.2 63 8 72 9△5.6
△14.7 60.0 669 754 △6.9 △15 4 58.5 65.3 73.5△6.2 △
15.0 58.2 64.5 74.1△6 3 △1
5 9 585 642 732 △5.7 △14 7 Comparative example 8 lI Dark green 03.5 61.3 67,3 77
．． 5△60△16.2 9 // Dark green 66.4 64.9 71,7 77
．． 0△53△12. l 10 Reddish black 60.8 58.1
64.2 72.6△6.1△l4.5 From the above results, compounds 1 to 7 of the present invention are superior to commercially available black color-forming compound 10 having a methyl group at the 6-position in terms of color density and light fastness. Shows equally excellent performance. Furthermore, the compound used in the present invention is superior to Compounds 8 and 9 with similar structures in terms of color density, hue, light resistance, etc.

The compound shown in Comparative Example 9 had a small Δ value or a significantly low concentration of the colored substance.

As described above, the fluoran derivative used in the present invention has no inferiority in performance as a color-forming dye compared to existing fluoran derivatives, and the color-forming recording material of the present invention has little color change during color development and fading, and can achieve the desired color development. Indicates that it is possible to provide a recording material that develops different hues.

Next, the effect on phenolic resin-based color developers that do not contain a salicylic acid skeleton will be described. Four types of compounds are shown. Substantially similar effects are shown for other compounds.

Initial evaluation of CF paper (B) 1 (A) Dark green 62.63
Dark green 6l. 7 5 /l Dark green 622 7 Green 62. 1 reached 2h
rs 4hrs 60.9 68.0 77.3△7.1 △
16.4 592 679 779 △8 7 △187 59 9 68.1 78.2△8.2 △
18.3 59.8 66.9 76.910 no! Black 61.9 59.5 66.3 75.6
△6.6 △l5.9 l5 In general, the light resistance and color density tend to be slightly lower than that of salicylic acid-based color developers, or the light resistance is inferior compared to commercially available black color-forming compounds (lO). , no hue or black. In other words, the fluoran derivative used in the present invention does not exhibit excellent performance when used as a non-salicylic acid color developer (B), but exhibits selectively excellent coloring effects when combined with a salicylic acid color developer (A). Indicates that the instrument plays the following.

Example 2 Effect on 3.5-c-α-phenethylsalicylic acid zinc salt An aqueous suspension of 3.5-c-α-phenethylsalicylic acid zinc salt was prepared in the same manner as in Example 1, and this was used to A paint solution containing a pigment (composition strength was the same as in Example 1) was prepared and coated on high quality paper to obtain CF paper with a coating weight of 5 g/m2. Using this CF paper, the same test as in Example 1 was conducted using CF paper prepared by encapsulating the following compounds in the same manner as in Example 1. The results were as follows.

l6 Initial arrival 2hrs 4hrs △5.7 △l3.7 7 Greenish black 56.5 53,4 59
,3 67.0△5 9 △13 6 11 Reddish black 57.3 54,3
60,0 67.8△5.7 △13.5 IO Reddish black 56,1 53,1
58.7 66.7 (comparison)
Δ5.6Δl3.511 is the compound of No. 4, and both RR2 and n-C*H are groups.

From the above results, the compound of the present invention showed an effect comparable to that of the commercially available product (10), and expanded the range of fluoran compounds that can be used in combination with this type of color developer.

Example 3 Effect on substituted zinc salicylate color developer (Part 2) The same method as in Example 1 was applied to commercially available CF paper which is said to use a compound of zinc salt obtained by salicyl oxidation of terpenized phenol as a color developer. A combination test was conducted using CB paper containing the compound. The results are shown below, demonstrating the usefulness of the compounds of the present invention.

Initial Bessatsu 2hrs 4hrs △5 9 △l3.9 12 Black 59,3 53,8
59,8 68.3△6 0 △14 5 10 Reddish black 59,0 54.2
59.9 67.9 (comparison)
The compound numbered Δ57Δ13712 has R1.CH3. in the compound number 6. Example 4 of the compound that became R2-cyclohekynyl Effect on CF paper using a resin obtained by condensing alkylphenol and salicylic acid with formaldehyde as a color developer Commercially available color developer which is a resin obtained by condensing alkylphenol and salicylic acid with formaldehyde In the same manner as in Example 1, it was made into a paint, used as CF paper with a coating weight of 5 g/m2, and tested. The results are shown below, which clearly demonstrate the effectiveness of the compounds of the present invention.

Initial Bessatsu 2hrs 4hrs △1 6 △3.1 5 Black 60.3 58.3
60,0 61.7△l 7 △34 10 Reddish black 60.1 57.9
59,3 60.9△1.4 △3.0 In Examples 2 to 4, compounds 8 and 9 in particular also showed similar trends to Example 1 in terms of hue, density, and light resistance.

Example 5 Creation of thermal recording material A thermosensitive recording material was prepared using the following recipe.

Pigment dispersion Pigment (combination of numbers 1 and 4) 6 parts 10% polyvinyl alcohol soluble in water 'K! i 6 parts water
1
0 parts The above-mentioned mixture was pulverized to a particle size of 3 μm using a sand mill to obtain a dispersion. On the other hand, a zinc salt of a condensate of phenethylated salicylic acid and a styrene oligomer was dispersed in the same method as the dye dispersion to obtain a color developer dispersion. Next, 50 parts of 60% lime carbonate aqueous dispersion, 20 parts of pigment dispersion, 70 parts of color developer dispersion, and 20 parts of zinc stearate.
% aqueous dispersion 20 parts, 20% of β-naphthylhenzoate
20 parts of aqueous dispersion, 10% polyvinyl alcohol aqueous solution
00 parts, 10 parts of a 30% paraffin wax aqueous dispersion, and 50 parts of water were combined and coated on high-quality paper with a basis weight of 50 g/m2 to a dry coating weight of 6 g/m' to form a heat-sensitive recording paper. Obtained. A heat-sensitive recording paper made with a sample using compound No. 10 as the dye was used to develop black color using a commercially available Facun Milli machine, and the color development was compared (color density was measured using a Maches reflection densitometer).
.

Hue Color density Invention product Pure black 1.25 Compound 10 (
Comparison) Reddish black 1. The light resistance and ura resistance of the color image of Compound 23 are also good, and are excellent like Compound 10.

Claims (1)

[Claims] (1) General formula (I) ▲Mathematical formulas, chemical formulas, tables, etc.▼(I) (In the formula, R_1 and R_2 may be the same or different and represent an alkyl group or a cycloalkyl group, and R_3 is m-chlorophenyl , 2-methyl-4-chlorophenyl, 4-methyl-2-chlorophenyl, 3,5-dichlorophenyl, 3,4-dichlorophenyl, 2,4-dichlorophenyl, 3-chloro-4-methylphenyl or 4
-Chloro-3-methylphenyl group) as a color-forming chromogen, and a color-forming recording material comprising a combination of a color-forming material containing a salicylic acid skeleton in the molecule. .