JPS58177393A - Diazo base heat-sensitive recording material - Google Patents

Abstract

PURPOSE:To improve preservability and ground coloring property, by providing a heat-sensitive color forming layer comprising respective specified amounts of a diazo compound, a color coupler which is a mixture of a naphthol derivative and an anilide compound of specified structural formulas and a thermoplastic substance. CONSTITUTION:A diazo compound, a mixture of a naphthol derivative of formula I (wherein X is hydrogen, halogen or the like; R<1> is an aromatic group or an alicyclic group; n is O or 1) and an anilide compound of formula II (wherein each of X1 and X2 is hydrogen, halogen, alkyl or the like; R<2> is an aromatic group or an acyl group) and 5-30pts.wt. (per 1pts.wt. of the diazo compound) of a thermoplastic substance are dissolved into a solvent to prepare a coating liquid. The coating liquid is applied onto a base and is dried to form a heat- sensitive color producing layer, thereby obtaining a diazo base heat-sensitive recording material.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a diazo-based heat-sensitive recording material that has excellent black color development, as well as excellent storage stability and background discoloration.

In addition to being used as copy paper for books and documents, thermosensitive recording materials are also used as output recording paper for computers, facsimile machines, medical measuring machines, etc., as well as thermal recording magnetic ticket paper and thermal recording label paper. be done. In addition, heat-sensitive recording materials can be used to record securities, gift certificates, admission tickets, certificates, etc. by taking advantage of the ease of automatic recording. ' It is also considered to be used as paper for creating % slips, etc. However, for such uses, heat-sensitive recording materials must be able to be fixed in order to obtain high recording reliability. No.

Conventionally, as fixable heat-sensitive recording materials, diazo-based materials that utilize a color-forming reaction between a diazo compound and a coupler are known. However, from the practical point of view, conventional products are still unsatisfactory in terms of black color development, shelf life, and background discoloration. for example,
When used as a coupler on phloroglucin, a black color-forming recording material can be obtained, but this material has the problem of poor storage stability and background discoloration. On the other hand, it is also known that a mixture of a blue coloring material and a yellow coloring material is used as Kagura to obtain a black coloring recording material, but in this case as well, satisfactory results cannot be obtained. . That is, when trying to obtain black coloring with such a mixed system, 2,3
A mixed system of a blue color-forming coupler made of -dihydroxy/naphthalene-6-sulfonic acid and a yellow color-forming coupler made of acetoacetanilide has been adopted. It has disadvantages such as poor coupling speed with diazo, which results in no sharpness, and because it is easily soluble in water, it causes background fog.

As a result of repeated efforts to develop a diazo-based heat-sensitive recording material that overcomes the drawbacks and has significantly improved black color development, as well as excellent storage stability and background discoloration, it was discovered that a special combination of couplers was used. and that the purpose is achieved by using a thermofusible substance,
The present invention has now been completed.

According to the present invention, in a diazo-based heat-sensitive recording material having a heat-sensitive coloring layer containing all of a diazo compound, a coupler, and a heat-fusible substance, a naphthol derivative represented by the following general formula (+) is used as the coupler. A mixture of a blue color-forming coupler consisting of , is used in a proportion of 5 to 30 parts by weight.

2 In the above general formula 0), is an aromatic group (e.g.
In the case of n-0, phenyl or naphthyl without rrts, or phenyl substituted with a substituent such as rogen, alkyl, aryl, alkoxy, nitro group, droxy group, alkoxycarbonyl group, sulfonic acid group, amidosulfo 7m4, etc. or naphthyl, and when n = 1, unsubstituted phenylene, naphthene/, bisphenylene, or phenylene, naphthylene, bisphenylene substituted with the various substituents described above), or alicyclic group (for example, n = 0
In the case of n-1, unsubstituted 7-chlorohexyl or cyclohexyl substituted with the various substituents shown for the aromatic group, etc., and in the case of n-1, unsubstituted cyclohexyl/or cyclohexylene substituted with the various substituents shown above. ) tomorrow, nkma O or l.

Specific example 1+ of the naphthol derivative represented by general formula (1)
For example, naphthol AS1 naphthol, HeSD, naphthol As-0L, naphthol As-R
L.

Naphthol-/L=AS-PH, Naphthol AS-VL, Naphthol As-E, Naphthol As-B5. Naphthol As-Hlt, Naphthol As-BO, Naphthol As
-SW.

Naphthol As-TR, Naphthol As-IT turtle Naphthol As-BG, Naphthol A8-KB, Naphthol As-LC, Naphthol As-LT, Naphthol 8S
-MX, naphthol As-BM, naphthol As-C
In addition to A etc., 3-hydroxy-2-naphthoem m-3'
-hydroxy-anilide, 3-hydroxy-2-naphthoic acid-3'-acetyl-anilide, 3-hydroquino-2
-naphthoic acid-3'-aminosulfo(-5o3NH2)
-anilide, 3-hydroxy-6-bromo-2-naphthoic acid-6'-methoxy-anilide, 3-hydroxy-2
-Naphthoic acid-3'-hydroxy-4'-methyl-anilide, 3-hydroxy-2-naphthoic acid-37-medoxycarbonylanilide, 3-hydroxy-2-naphthoic acid 4/-sulfo-anilide, 3- Hydroxy-6-sulfo-2-naphthoic acid-2'-methyl-anilide, 3-
Hydroxy-2-naphthoic acid-4'-methoxy-5'-
Examples include hydroxy-anilide. All of these naphthol derivatives form blue azo dyes when subjected to a color-forming reaction with a diazo compound.

In the general formula (n), Xl and X2 are hydrogen, nitrogen (e.g. chlorine, bromine, fluorine), alkyl (e.g. alkyl having 1 to 4 carbon atoms such as methyl, ethyl, propyl, butyl), alkoxy (alkoxy having 1 to 4 carbon atoms such as methoxy, ethoxy, propoxy, butoxy) or aryloxy (e.g., phenoxy, tolyloxy, etc.), 1 (2 is the same aromatic group as shown for R1 above) or It is an alicyclic group, preferably including substituted or unsubstituted phenyl and cyclohexyl.

Y is a cyano group (-ON) or an afur group (for example, aliphatic groups having an alkyl group having 1 to 4 carbon atoms such as acetyl, propionyl, butyryl, valeryl, hexahydrobenzoyl, be/diyl, toluoyl, salicyloyl, etc.) or an aromatic type having a phenyl group substituted with the substituent shown in connection with hole 1).

Specific examples of the anilide compound represented by the general formula (II) include the following.

4-Benzoylamino-2,5-jethoxy-acetoacetanilide 4 (2/-Chlorbenzoylamine)-2,s-dimethoxyacetoacetanilide 4-Benzoylamino-(2'-chlorobenzoyl)acetanilide 4-Benzoylamino-acetanilide Acetanilide 4-benzoylamino-2,5-jethoxy-cyanoacetanilide 4-(p-methylbenzoylamino)-acetoacetanilide 4-benzoylamino-2,5-dyptoxy-acetoacetanilide 4-(p-methoxybenzoylamino)-2゜5-Diethoxyacetoacetanilide 4-(p-methoxybenzoylamino)-2-chloro-5-butoxy-acetoacetanilide All of the above-mentioned anilide compounds produce a yellow azo compound when subjected to a color reaction with a diazo compound. Form a dye.

In the present invention, the naphthol derivative and anilide compound described above are mixed and used as a coupler. In this case, the ratio of the two is generally in the range of 1:5 to 5:1, and the desired black coloring is achieved. Mix to obtain the desired properties. In the present invention, the naphthol compound represented by the general formula (+1) and the anilide compound represented by the general formula ([l) both have a larger molecular weight than phloroglucin, acetoacetanilide, etc., and are difficult to dissolve in water.
To provide a stable mixed coupler which has excellent storage stability and is resistant to oxidation.

In the present invention, all of the above-mentioned mixed couplers are used, and a relatively large amount of a thermofusible substance is used in order to enhance the color development of the mixed coupler. The amount of this thermofusible substance is 5 to 30 parts by weight per 1 part by weight of the diazo compound.
The proportion is 7 to 20 parts by weight, preferably 7 to 20 parts by weight. Further, the coupler particles are preferably fine particles of 10 μm or less.

In addition, the heat-sensitive color forming layer as used in the present invention refers to one layer or a multilayer of two or more layers formed to support heat-sensitive color forming layer forming components such as a diazo compound, a coupler, and a thermofusible substance on a support. This means the entire coating layer. Therefore, the thermosensitive color forming layer forming components are simultaneously contained in one coating layer, or
Alternatively, it is appropriately divided and contained in two or more multilayer coating layers.

In the present invention, a heat-sensitive coloring layer having a two-layer structure is adopted, in which a diazo layer containing a diazo compound and a thermofusible substance is provided as the lower layer, and a coupler layer containing a mixed coupler and a thermofusible substance is provided on top of the diazo layer. is preferable.

As the diazo compound used in the present invention, commonly used ones, such as those represented by the following general formula, can be used.

9 However, general formula [! ], (It) and CIl+), RI +R6+J is hydrogen, halogen, 01-C3 alkyl group is also Rerrz hydrogen, halogen, C, -C, alkyl group is moji, alkoxyl group, R4, RsVi same -
Or a different C.

~C3 alkyl group, hydroxyalkyl group, or alkoxyl group, or hahalogen), R7Fi hydrogen,
Halogen, trifluoromethyl group, 01-C6”+5
+ FL+6 'Same as RI3), M,, M2. Ms
is an acid residue or an acid residue forming a double salt with a metal salt. In this case, the acid residues include halogen ions, BF-,
, PF″6 is preferable, while metal salts that form double salts with acid residues include, for example, ZnO1!2, 0dO12, SnO!1
There are 2 etc.

Y represents -CH2- or -〇〇-, and n is 0 or 1.

Specific examples of those corresponding to general formula (1) include the following.

Specific examples of those corresponding to the general formula CI+) include the following.

A specific example of something that falls under the general formula ([[) is 14
/II For example, the following can be mentioned.

Slj 2 M 5 / CI! 0H3 In the present invention, in order to obtain a more commercially available product with long shelf life, it is advantageous to use the diazo compound in the form of a water-insoluble salt such as a fluorate-containing salt such as -BF4 or -PF6. be.

As the thermofusible substance used in the present invention, one having a melting point or softening point in the range of 50 to 250°C is employed, and specific examples thereof include the following.

Alcohol derivatives such as 2-tribromoethanol, 2,2-dimethyltrimethylene glycol, 1,2-cyclohexanediol, acid derivatives such as malonic acid, glutaric acid, maleic acid, methylmaleic acid, beeswax, shellac wax, etc. Animal hooks, vegetable waxes such as carnauba wax, mineral waxes such as montan wax, petroleum waxes such as paraffin wax and microcrystalline wax1,
Other synthetic waxes such as polyalcohol esters of higher fatty acids, higher amines, higher amides, condensates of mono-fatty acids and amines, aromatic and amine condensates, synthetic paraffins, chlorinated paraffins, metal salts of higher fatty acids, Higher straight chain glycols, dialkyl 3,4-epoxyhexahydrophthalate, etc.

In the present invention, a binder is used as necessary in order to firmly support the thermosensitive coloring layer on the support.
Examples of such things include the following:

Polyvinyl acetate, polyvinyl chloride, vinyl chloride/vinyl acetate copolymer, polyacrylic ester, polystyrene, polybutadiene, polyacrylamide, styrene/butadiene/acrylic copolymer, polyvinyl alcohol, polyacrylamide, casein, gelatin, starch and its derivatives, polyvinylpyrrolidone, carboxymethylcellulose, methylcellulose, ethylcellulose, polyester (MW of 100,000 or more), polystyrene (
MW of 100,000 or more), water-soluble, organic solvents such as chlorinated rubber, styrene-maleic anhydride copolymer, in(or diiso)butylene-maleic anhydride copolymer, urea-formalin resin, phenol resin, melamine resin, etc. Soluble or aqueous dispersion resin.

In the present invention, as a binder, ? For this purpose, it is preferable to use thermofusible or thermosoftening agents with a melting point or softening point of 50 DEG to 250 DEG C., and such binders also act as thermofusible substances for use in the present invention.

Further, in the present invention, the heat-sensitive coloring layer may further contain acidic substances, basic substances, fillers, and other substances as auxiliary components, if necessary.

Acidic substance: An acidic substance is added as necessary to prevent a coupling reaction and for storage stability, and examples thereof include the following.

intaric acid, citric acid, boric acid, lactic acid, gluconic acid, sulfuric acid, etc.

Basic substance: A basic substance is added as necessary to cause the entire coupling reaction to occur during heating, and examples thereof include the following.

Caustic alkalis and alkali carbonates such as sodium hydroxide, calcium hydroxide, potassium carbonate, etc.

Substances that generate basicity when heated include urea, thiourea and their derivatives, alkali salts of trichloroacetic acid,
Ammonium chloride, ammonium sulfate, ammonium citrate.

Filler: A filler is added to improve the matching property to a thermal head when heating is performed by a thermal head, and examples of such fillers include the following.

Organic and inorganic solid particles such as styrene resin particles, urea-formalin condensate resin particles, aluminum hydroxide, magnesium hydroxide, calcium carbonate, titanium, talc, kaolin, silica, and alumina.

Other auxiliary ingredients include zinc chloride, zinc sulfate, sodium citrate, and afllf to suppress or assist color development.
Anidine, calcium gluconate, sorbitol, saccharose, etc. are used.

In order to obtain the heat-sensitive recording material according to the present invention, each layer-forming coating solution is prepared by dissolving or dispersing the above-mentioned forming components in an appropriate solvent, and this coating solution is applied to a support to form one or more layers. Each is applied, dried, and made into a product. In this case, the solvent for dissolving or dispersing the layer-forming components is appropriately selected depending on the properties of the layer to be formed and the purpose of formation. Such solvents include water or an aqueous medium obtained by dissolving an organic solvent in water, benzene, toluene, xylene, n-hexane, n-hegetane, cyclohexane, kerosene, methyl isobutyl ketone, methyl cellosolve, acetone, Examples include nonpolar or polar organic solvents such as methyl ethyl ketone, dimethyl ether, and siloxane.

Next, the present invention will be explained in more detail with reference to Examples.

Example 1 [Liquid A] Stearic acid amide 7
Vinyl chloride vinyl acetate copolymer 5 Methyl cellosolve 87 The above composition was dispersed in a ball mill to prepare [Liquid A].

[Liquid B]

2 parts by weight of naphthol As 4-be/shylamino-2,5-jethoxy 3 .

-Acetoacetanilide N-stearylbenzamide 10 Imidazole 5 Silica
5 Isobutylene maleic anhydride copolymer 5 parts by weight water
70 [Liquid B] was prepared by dispersing the above composition in a ball mill.

5017 m2 of high-quality paper was undercoated with calcium carbonate and polyvinyl alcohol (PVA) to a dry weight of 297 m2. On top of that, ArL was applied and dried to a dry weight of 2.5 f/m2, and then Bi was added on top of that to a dry weight of 2.0 f/m2. /m2, apply and dry, and record heat! il-obtained.

The obtained heat-sensitive recording material is sent by facsimile (RIFAX33
00), a black color developed. Further, this was exposed to light using Ricopy High Start 100 and fixed. When measured with a Macbeth densitometer, the print density was 0.96 and the background density was 0.10. In addition, the thermal paper before exposure was heated to 40°C.
After being left in a dry environment at 90% humidity (RH) and 60°C for 24 hours, the skin density was 0.
．． 15, 0.18. Also, after pasting thermal paper on the wall of a general office for one month, the skin density was 0.
．． It was 12.

[Liquid C]

Stearic acid amide 7 Water 82
Thermal paper (il-) was manufactured in the same manner as in Example 1, and the Ip paper was tested. In the printing test, results of print density (1.90, background density 0.11, 40
℃、I! n: If (1ull) In the storage test under 90% conditions, the skin? A result of aK0.19 was obtained, and a storage test under dry conditions at 60°C showed a skin density of 0.
21 results were obtained. In addition, when stored for a period of - month, a resultant with a skin density of 0.15 was obtained.

Example 3 A product was obtained in the same manner as in Example 1, except that the naphthol derivatives shown below were used instead of naphthol AS, and tests were performed on it. In this case, the same results as in Example 1 were obtained. It was done.

Table-1 Example 4 In Example 1, the following table is used as the anilide compound.
2 Comparative Example 1 A product was obtained in the same manner as in Example 1, except that 3 parts by weight of phloroglucin was used instead of the two types of couplers used in the OB liquid, and the dry weight was 2.2 y/m2, and the product was tested.

In the printing test, a print density of 1.05 and a background density of 0.11 were obtained, and in a storage test under conditions of 40°C and 90% humidity (R, H), a background density of 0.26 was obtained.
In a storage test under dry conditions at 0°C, a skin density of 0.30 was obtained. In addition, in a long-term storage test for -month, a skin density of 0.32 was obtained. By comparing these results with the results shown in the examples above, it can be seen that the product of the present invention is excellent in storage stability and background discoloration.

Comparative Example 2 In Example 2, 3 parts by weight of fuglucine was used instead of the mixed coupler, and the dry weight was 1. A product was obtained and tested in the same manner except that sy/m2 was used. In the printing test, a print density of 0.98 and a background density of 0.11 were obtained, and in a storage test at 40°C and a density (FLH) of 90%, a result of a background density of 0.25 was obtained, and at 60°C. ,
In a storage test under dry conditions, a background density of 0.32 was obtained. In addition, in a long-term storage test of - months, the skin concentration was 0.
．． Thirty-four results were obtained.

Comparative Example 3 In Example 1, the amount of stearic acid amide in Afi of Example 1 was changed to 2.0 parts by weight, and the dry weight was 1,597 m2.
A product was obtained and tested in the same manner as in Example 1, except that the amount of N-stearylbenzamide in liquid B was 5.0 parts by weight and the dry weight was 1,697 m2. In the printing test, the printing density was 0.70. Skin density 0.
In the storage test at 40°C and 90% humidity (RH), a skin density of 0.16 was obtained, and in the storage test at 60°C and dry conditions, the skin density was 0.2.
A result of 1 was obtained. In addition, as a result of a long-term storage test for -month, a skin density of 0.13 was obtained. From this result, it can be seen that when the amount of the thermofusible substance is small, the desired color development cannot be obtained.

Comparative Example 4 In Example 1, -CONH was used instead of the naphthol derivative.
A product was obtained and tested in the same manner except that 1-hydroxynaphthalene-4-sulfonic acid under-8-N-isopropylsulfonamide having no R' bond was used. In the printing test, the print density was 0.87 and the background density was 0.1.
A storage test under conditions of 40°C and 90% humidity (RH) resulted in a skin density of 0.36, and a storage test at 60°C and dry conditions resulted in a skin density of 0.36.
42 results were obtained.

-! The results of a long-term storage test for one month showed that the skin concentration was 0.
24 results were obtained. From this result, it can be seen that when the naphthol derivative specified in the present invention is not used, the product is inferior to the product of the present invention in terms of storage stability and skin fading.

Comparative Example 5 In Example I, instead of 4-benzoylamino-2゜5-jethoxyacetoacetanilide, 1L20ON
A product was obtained and tested in the same manner except that 2,5-jethoxyacetoacetanilide having no H-bond was used. In the printing test, the print density was 0.82, the background density was 0.1'5, and the temperature was 40'C.

A storage test under conditions of 90% humidity (RH) yielded a skin density of 0.42, and a storage test under dry conditions at 60°C yielded a skin density of 0.38. In addition, as a result of a - month long-term storage test, a skin density of 0.32 was obtained. This result shows that when the anilide compound specified in the present invention is not used, the product is inferior to the product of the present invention in terms of storage stability and skin fading.

Patent applicant Ricoh Co., Ltd. Agent Patent Attorney Toshiaki Ikeura

Claims (1)

[Claims] (1) A diazo-based thermographic (formula 1
．． X is hydrogen, halogen, alkoxy or sulfonic acid group,
FLI is an aromatic group or an alicyclic group, n is O or 1) and a naphthol derivative represented by the general formula alkoxy/,
or aryloxy, 1t2 is an aromatic group or alicyclic group, and Y is an ano group or an afur group). For 1 part by weight of the compound, 5
A diazo-based heat-sensitive recording material, characterized in that it is used in an amount of ~30 parts by weight.