JPS60184880A - Diazo thermal recording material - Google Patents

Abstract

PURPOSE:To obtain a diazo thermal recording material having an excellent black color forming property, favorable preservability and light fading resistance, by using a specified blue color forming coupler and a specified yellow color forming coupler in combination. CONSTITUTION:A blue color forming coupler of general formula ( I ), wherein each of R<1> and R<2> is hydrogen or lower alkyl, particularly, 1-4C alkyl, and a yellow color forming coupler of general formula (II), wherein each of R<1> and R<4> is hydrogen, lower alkyl, preferably, 1-4C alkyl, and each of R<2> and R<3> is lower alkyl, preferably, 1-4C alkyl, are used in combination as couplers in a diazo thermal recording material comprising a diazo compound, a coupler and a heat- fusible substance supported on a base. The blue coupler and the yellow coupler are preferably used in a weight ratio of 1:5-5:1. The combination of the couplers yields a diazo thermal recording material capable of forming a color of pure black tone with high density.

Description

[Detailed description of the invention] 〔Technical field〕 The present invention relates to a diazo thermosensitive recording material.

[Prior art]

Diazo-based heat-sensitive recording materials are widely known, in which a heat-sensitive layer containing a diazo compound, a coupler, and a heat-fusible substance as main components is provided on a support such as paper or a plastic film.

In this diazo thermosensitive recording material (or heat-developable diazo copying material), it is difficult to develop a black color with a single coupler, and phloroglucin is the only practical coupler of this type.

However, this material has problems with moisture resistance due to its water solubility and color tone changes due to fading. Therefore, in general, in order to produce black, a combination of two or three types of couplers is essential. For example, sodium 2,3-dihydroxynaphthalene-6-sulfonate (blue), acetoacetanilide (yellow), (sepia) and other combinations are known. However, these also had the same problems as described above. In addition, a poorly water-soluble yellow coupler
072, but it had the disadvantage that it easily faded.

〔the purpose〕

An object of the present invention is to overcome the above-mentioned drawbacks of the diazo heat-sensitive recording materials proposed so far, and to provide a heat-sensitive recording material that provides excellent black color development, has good storage stability, and is resistant to photofading.

〔composition〕

According to the present invention, in a diazo thermosensitive recording material in which a diazo compound, a coupler, and a thermofusible substance are supported on a support, the couplers include a blue coloring coupler represented by the following general formula (1) and a general formula ( A diazo-based heat-sensitive recording material is provided, which is characterized in that it uses a yellow color-forming coupler represented by I[).

General formula (■): R' In the formula, R1 and R2 represent hydrogen or a lower alkyl group, and as the lower alkyl group, those having 1 to 4 carbon atoms are particularly used.

General formula (■): In the formula, R1 and R4 represent a hydrogen atom, a lower alkyl group or a halogen, and R1 and R3 represent a lower alkyl group.

The lower alkyl group representing R1, R2, R3, and R4 preferably has 1 to 4 carbon atoms.

The combination of the blue coupler and yellow coupler represented by the general formulas (1) and (II) used together in the present invention provides a diazo thermosensitive material with pure black tone and excellent density.

Examples of the assembly of the blue coupler represented by the general formula (1) include the following.6 Specific examples of the yellow coupler represented by the general formula (II) include the following: can be shown.

The blue coupler represented by the general formula (1) and the yellow coupler represented by the general formula (II) used in the present invention are 1
It is preferable to use them together in a weight ratio of 1:5 to 5:l.

As the diazo compound used in the present invention, those used in the general formula for diazo photosensitive paper are applied, and examples thereof include those shown below.

Diazo Compound: As the diazo compound used in the present invention, a commonly used diazo compound, for example, one represented by the following general formula is used.

9 However, in general formula (13, (■) and (m), R1
, R6, R8 are hydrogen, halogen, C1 to C5 alkyl group or alkoxyl group, or
: Same as R2), R2, R3-R9 are hydrogen, halogen,
C1-C5 alkyl group or alkoxyl group, R4
, R5 is the same or different C1 to C5 alkyl group, hydroxyalkyl group, or -co(R13: hydrogen, C1 to C3 alkyl group or alkoxyl group, or halogen), R
7 is hydrogen, halogen, trifluoromethyl group, C1-C
5 alkyl group or alkoxyl group, -5-(Kaku)
-m-R16 (R1rs, 1lts, R16: Same as R13), M1, M1, and M3 are acid residues or acid residues forming a double salt with a metal salt. In this case, the acid residue is preferably a halogen ion or a fluorine-containing inorganic acid ion such as BF4 or PF6. On the other hand, the metal salt that forms a double salt with the acid residue is, for example, Zn. (122,C
Examples include dCl2z and 5nCnz.

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

CH3 Specific examples of those corresponding to general formula (II) are:

For example, the following can be mentioned:

Specific examples of those corresponding to general formula (111) are:

For example, the following can be mentioned:

Q In the present invention, in order to obtain a product with further improved long-term shelf life, it is necessary to use llBF4 and IIPF as the diazo compound.
It is advantageous to use it in the form of a water-insoluble salt such as a fluorine-containing salt such as s.

In the present invention, in order to improve high-speed color development.

A thermofusible material is used. Specific examples of such things include, for example, the following:

Alcohol derivatives such as 2-tribromoethanol, 2,2-dimethyltrimethylene glycol, and 1,2-cyclohexanediol, acid derivatives such as malonic acid, glutaric acid, maleic acid, and methylmaleic acid, and animals such as beeswax and shellac wax. waxes, vegetable waxes such as carnauba wax, mineral waxes such as montan wax,
Paraffin fuchs, petroleum waxes such as microcrystalline wax, other synthetic waxes such as polyhydric alcohol esters of higher fatty acids, higher amines, -higher amides, condensates of fatty acids and amines, condensates of aromatics and amines, synthetic paraffins , chlorinated paraffin, higher linear glycol, 3,4
- Dialkyl epoxy hexahydrophthalate, etc.

The thermofusible substance used in the present invention preferably has a melting point or softening point in the range of 50 to 250°C.

If the melting point or softening point is less than 50°C, the shelf life of the product tends to deteriorate, and if it exceeds 250°C, the thermal response of the product to the thermal head becomes unsatisfactory.

In addition, from the viewpoint of obtaining a product with high-speed coloring property (high-speed recording property), these thermofusible substances used in the present invention should be used in an amount of 2 to 30 parts by weight, preferably 5 to 30 parts by weight, per 1 part by weight of the diazo compound.
It is used in a proportion of 10 parts by weight. If this amount is less than the above range, the color development will be insufficient, and the resulting product will be
This makes it unsuitable as a recording material for high-speed recording. In the case of the present invention, it is particularly preferable to use 5 parts by weight or more for high-speed output recording such as facsimile. On the other hand, if the amount added is too large, blurring of the image may occur during color development by heating, which is undesirable. Therefore, in the case of the present invention, the amount of the thermofusible substance added is preferably kept within the above range.

Furthermore, in the present invention, acidic substances, basic substances, fillers, binders, and other substances may be used 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.

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

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.

Binder: A binder is used to stably support each component on a support, such as polyester, polystyrene, chlorinated rubber, polyvinyl acetate, polyvinyl chloride, polybutadiene, acrylic ester, vinyl chloride/ Vinyl acetate copolymer, polybutadiene, styrene/butadiene/acrylic copolymer, polyethylene, ethylene/vinyl acetate copolymer, styrene/acrylic copolymer, polyvinylidene chloride, vinylidene chloride/acrylic copolymer, phenolic resin, urea - In addition to organic solvent-soluble or water-dispersible resins such as formalin, resins, and melamine resins, polyvinyl alcohol, polyacrylamide, casein, gelatin,
Starch and its derivatives, polyvinylpyrrolidone, carboxymethylcellulose, methylcellulose, ethylcellulose, styrene-maleic anhydride copolymer, iso(
Alternatively, a water-soluble resin such as diiso)butylene-maleic anhydride copolymer can also be used.6 Basic substance: A basic substance is added as necessary to cause a coupling reaction during heating. Examples include things like:

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, etc.

To obtain the heat-sensitive recording material of the present invention, each of the above-mentioned components is dissolved or dispersed in an appropriate solvent to prepare a layer-forming coating solution, and this coating solution is coated on a support such as paper or film and dried. to form a thermosensitive coloring layer.

In the present invention, the heat-sensitive coloring layer provided on the support may be one layer or a multilayer of two or more layers. When forming a multilayer of two or more layers, the diazo compound, coupler, and heat-fusible or heat-softening substance may be contained in each layer in any manner. For example, (D + X)/ E
C+ X), CD)/EX)/(C), (C+ X)/
CD+X), (C+X)/(X)/(D+X
), each layer can be stacked. In addition,
In this case, (D) is a layer containing a diazo compound, [C]
is a layer containing a coupler, (X) is a layer containing a thermofusible substance, (o + X) is a layer containing a diazo compound and a thermofusible substance, (C + X) is a layer containing a coupler and a thermofusible substance. means a layer containing a sexual substance. Of course, these layers may also contain auxiliary components, such as fillers, acidic substances, alkaline substances, etc. Further, the auxiliary component does not need to be included in the layer together with one or more of the diazo compound, coupler, and thermofusible substance, and can be laminated on the support as a single auxiliary component layer. In this case, the lamination position is arbitrary, and in the present invention, it can be provided at any position as an upper layer, a lower layer, and an intermediate layer with respect to the layer containing the diazo compound, coupler, and thermofusible substance. The solvent for dissolving or dispersing the 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 solvent in which an organic solvent is dissolved in water, non-polar organic solvents such as benzene, toluene, xylene, n-hexane, n-hebutane, cyclohexane, kerosene, methyl isobutyl ketone, methyl Examples include polar organic solvents such as cellosolve, acetone, methyl ethyl ketone, and dimethyl ether.

〔effect〕

The diazo thermosensitive recording material of the present invention has the above structure,
Gives an image with high black density.

The heat-sensitive recording material of the present invention can be advantageously applied in various fields of heat-sensitive recording, particularly as output recording paper for facsimile machines, electronic computers, etc. that require high-speed recording, and in the case of the present invention, the surface The characters and images recorded in
After the image is formed by heating, it can be fixed by decomposing the unreacted diazo compound by light. Furthermore, the heat-sensitive recording material of the present invention can be applied to recording necessary information on securities, gift certificates, admission tickets, certificates, slips, etc., and for creating them, by taking advantage of its fixing properties.

〔Example〕

Next, the present invention will be explained in more detail with reference to Examples. Note that all parts and percentages shown below are based on weight.

Examples [Liquid A] Stearic acid amide 9n Vinyl chloride/vinyl acetate copolymer 5 Methyl cellosolve (J5n) The above composition was dispersed in a ball mill to prepare [Liquid].

[Liquid B]

(Blue coupler) (Yellow coupler) N-octadecylcarbamoylbenzene lol! Imidazole 5 Silica fine particles 5 n Methyl cellulose 5 n Water 7 Qn The above composition was dispersed in a ball mill to prepare [liquid B].

Next, 50 g/rr (calcium carbonate and P
VA was undercoated to a dry weight of 2 g/rd. Dry weight/1. On top of that, [N liquid] was applied so that the dry weight was 4.0 g/rd, and the Bekk smoothness was adjusted to 800 seconds using a calender. I got the material.

Comparative Example 1 A heat-sensitive recording material was obtained in the same manner as in Example except that the blue coupler and yellow coupler in [Liquid B] of Example were replaced with phloroglucin.

Comparative Example 2 A heat-sensitive recording material was obtained in the same manner as in the example except that the blue coupler and yellow coupler in [liquid B] of the example were replaced with the following.

Comparative Example 3 A heat-sensitive recording material was obtained in the same manner as in the example except that the blue coupler and yellow coupler in [Liquid B] of the example were replaced with the following.

Refax 33 the heat-sensitive recording material obtained as above.
00, and further exposed to light using Ricopy High Start 100, and the solid print density and background density were measured using a Macbeth densitometer RD-514. In addition, to examine image storage stability,
The heat-sensitive recording material was applied for 24 hours in an environment of 40° C. and 90% humidity, and the skin density was measured. This concentration was used to evaluate the storage stability.

Table 1 As can be seen from the results in Table 1, it is clear that the product of the present invention has a pure black color tone, high density, and excellent storage stability.

Patent applicant Rico Co., Ltd. Representative Patent Attorney Toshiaki Ikeura

Claims (1)

[Claims] (1) In a diazo heat-sensitive recording material in which a diazo compound, a coupler, and a thermofusible substance are supported on a support, the couplers include a blue coloring coupler represented by the following general formula (1) and a general formula (II). A diazo-based heat-sensitive recording material characterized by the use of a yellow color-forming coupler represented by: General formula (1): (In the formula, R1 and 1 (2 represents hydrogen or a lower alkyl group) General formula (■): (In the formula, ni and R4 represent a hydrogen atom, a lower alkyl group, or a halogen; R2, R'' represents a lower alkyl group)