JPS60264286A - Diazo type thermal recording material - Google Patents

Abstract

PURPOSE:To obtain excellent black developability and a high speed recording property, by laminating a diazo layer and a coupler layer to a support and allowing a heat-meltable substance to be contained in one of both layers forming a lower layer along with a water-insoluble binder in combination with a specific coupler and an imidazole derivative. CONSTITUTION:A diazo layer based on a diazo compound and a coupler layer based on a coupler are laminated to a support and a heat-meltable substance is contained in one of both layers forming a lower layer along with a water-insoluble binder and a black developable coupler shown by formula 1 is used as the coupler and, further, an imidazole derivative represented by formula 2 (wherein R<1> is a higher alkyl group or a hydroxyalkyl group and R<2>, R<3> and R<4> are hydrogen, a phenyl group, a benzyl group, an alkyl group, an alkoxy group, a hydroxyalkyl group or a cyanoalkyl group) is used in a part of the color forming system other than the diazo layer. The amount to be used of the imidazole derivative is 0.5-10pts.wt., pref. 1-10pts.wt. of the diazo compound. By this method, excellent black color developability and a high speed recording property are obtained.

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 the only practical coupler of this kind is prologlucin.

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. With conventional diazo photosensitive paper, ammonia water or alkaline aqueous solution is used as a developer when performing a color reaction.
We were able to adopt conditions that would allow a sufficient color reaction to occur,
Furthermore, even when the coloring reaction was carried out by heating, a sufficient amount of heat could be supplied. Therefore, in the case of diazo-sensitive paper, no special measures were required to cause the color reaction to occur at high speed. However, in the case of a thermal recording material that performs a coloring reaction with a small amount of thermal energy, such as a thermal head or a thermal pen, which is the object of the present invention, an image forming means such as that used in the case of diazo photosensitive paper is not used. Therefore, it is particularly desired to develop a heat-sensitive recording material that can efficiently cause a coloring reaction by using less thermal energy.

〔the purpose〕

An object of the present invention is to overcome the above-mentioned drawbacks of the diazo-based heat-sensitive recording materials proposed so far, and to provide a heat-sensitive recording material that can provide excellent black color development and has excellent high-speed recording performance (sensitivity). be.

〔composition〕

According to the present invention, a diazo layer containing a diazo compound as a main component and a coupler layer containing a coupler as a main component are laminated on a support, and the layer forming the lower layer of the diazo layer and the coupler layer is heated. A fusible substance is contained together with a water-insoluble binder, a black color-forming coupler represented by the following structural formula is used as the coupler, and an imidazole derivative represented by the general formula is used in a part of the color-forming system other than the diazo layer. A diazo-based heat-sensitive recording material is provided, which is characterized in that it contains.

R1 is a higher alkyl group (usually has 6 to 24 carbon atoms)
) or an alkoxy group or hydroxyalkyl group derived from a higher alkyl group, and R2, R3 and R
4 is hydrogen, phenyl, benzyl, an alkyl group, an alkoxy group, a hydroxyalkyl group, or a cyanoalkyl group, and the number of carbon atoms in these alkyl groups, alkoxy groups, hydroxyalkyl groups, and cyanoalkyl groups is not particularly limited, and is usually It has 1 to 24 carbon atoms.

Examples of the imidazole derivative represented by the above general formula include the following.

2-undecylimidazole, 2-heptadecyl imidazole, 2-undecyl-4-methylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-cyanoethyl-2-heptadecyl-4-methylimidazole, 1- Benzyl-2-heptadecyl-4-
Methylimidazole etc.

In the heat-sensitive recording material of the present invention, the stacking order of the diazo layer and the coupler layer is arbitrary, but the layer forming the lower layer contains a thermofusible substance together with a water-insoluble binder. With this configuration, the lower layer becomes hydrophobic. In addition, in the present invention, the above-described method is applied to a part of the coloring system other than the diazo layer, such as a coupler layer, a support, or an undercoat layer, an overcoat layer, and an intermediate layer formed as necessary. Contain the indicated imidazole derivative. Inclusion of this substance in the diazo layer is not preferable because it impairs the shelf life of the product. The amount of the imidazole derivative used is 0.00 parts by weight per 1 part by weight of the diazo compound.
The proportion is 5 to 10 parts by weight, preferably 1 to 10 parts by weight. Note that the thermofusible material can be contained in the upper layer as well as the lower layer, or can be laminated as an independent thermofusible material layer.

The heat-sensitive recording material of the present invention has excellent thermal responsiveness and storage stability due to the above-described layer structure.

The diazo compounds used in the present invention are those used in the general formula for diazo photosensitive paper, and include, for example, 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.

However, in general formulas (1), (II) and (m), R
1, R6, R8 are hydrogen, halogen, C1 to C5 aR1
2: Same as R2), R2, R3, R are hydrogen, halogen, C1 to C5 alkyl group or alkoxyl group, R
4, R5 is the same or different C1 to C5 alkyl group,
hydroxyalkyl group, alkyl group or alkoxyl group, or halogen) R7
is hydrogen, halogen, trifluoromethyl group, Ml, Ml
, M3 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 and B
Fluorine-containing inorganic acid ions such as F: and PF stone are preferable, while metal salts that form double salts with acid residues include, for example, 7-ZnCQ2, CdCj2z, and 5nCfiz.

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

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

Specific examples of those corresponding to U 8- general formula (III) include the following.

In the present invention, in order to obtain a product with further improved long-term shelf life, HBF4 and HPFB are used as diazo compounds.
Advantageously, they are used in the form of water-insoluble salts such as fluorine-containing salts.

In the present invention, a thermofusible substance is used to enhance rapid color development. 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 1 part by weight, per 1 part by weight of the diazo compound.
It is used in a proportion of 0 parts by weight. If this amount is less than the above range, color development will be insufficient and the resulting product will be 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 in facsimile machines. 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. Examples 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.

Styrene resin fine particles, urea-formalin condensate 12- Fat fine particles, organic and inorganic solid particles such as 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 resin and melamine resin, polyvinyl alcohol, polyacrylamide, casein, gelatin, starch and its derivatives, polyvinylpyrrolidone, carboxymethylcellulose, methylcellulose, ethylcellulose, styrene-maleic anhydride can be used. Water-soluble resins such as copolymers and iso(or diiso)butylene-maleic anhydride copolymers can also be used.

Basic substance: A basic substance is added as necessary to cause a coupling reaction 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, 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. In the case of two or more layers, the diazo compound, coupler, and heat-fusible or heat-softening substance can be contained in each layer in any way. For example, CD+X)/(c+
x), CD)/(X)/(C), (C+X)/(D+X
), (C+X)/[X]/[D+X], etc. can be laminated. 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, (0+
X) is a layer containing a diazo compound and a thermofusible substance, [
c + X] means a layer containing a coupler and a thermofusible 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 it can be provided at any position as an upper layer, a lower layer, or an intermediate layer with respect to the layer containing the diazo compound, coupler, and thermofusible substance.

15- In the present invention, 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 solvent in which an organic solvent is dissolved in water, benzene, toluene, xylene, n-hexane, n-hebutane, cyclohexane,
Examples include nonpolar organic solvents such as kerosene, polar organic solvents such as methyl isobutyl ketone, methyl 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 one image is formed by heating, it can be fixed by decomposing the unreacted diazo compound with light. In addition, the heat-sensitive recording material of the present invention can be applied to record necessary information on evaluation coupons, gift certificates, admission tickets, certificates, slips, etc., and to create 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] N-cyclohexylstearamide 10 Vinylidene chloride-acrylic copolymer 20 Methyl ethyl ketone 5 (3n) [Liquid B] Silica (thyroid...244) 10II Polyvinyl alcohol 5 u Water 83II [Liquid C] 2-Undecylimidazole 51+ Stearic acid amide '1On Styrene/acrylic copolymer 20!!Water 50/l [Liquid D] 2-Heptadecyl imidazole 5/7 Ammonium salt of diisobutylene-maleic anhydride copolymer 1011 Water 70! Comparative example [Liquid E]: The black coloring coupler in Solution C was replaced with resorcin, and 2-undecylimidazole was removed [Liquid F] = The black coloring coupler in Solution D was replaced with a combination of a blue coupler and a yellow coupler. , 2-heptadecylimidazole removed 19- Table 1 Examples 1 to 2 of the contents of Table 1 above. High-quality paper (approximately 50 g/
Approximately 2 g of polyvinyl alcohol was placed on rd high-quality paper (
A heat-sensitive layer was formed by applying and drying the heat-sensitive layer with each layer having an adhesion amount of 2 to 3 g (solid content), and further calendering to obtain a Bekk smoothness of 500 seconds. A thermosensitive recording material was obtained.

Refax 33 the heat-sensitive recording material obtained as above.
00, and then exposed using Ricobee High Start 100, and the solid print density and background density were measured using a Macbeth densitometer RD-514. In addition, in order 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 as an evaluation of storage stability.

20-Table-2 As can be seen from the results in Table-2, it is clear that the product of the present invention has a pure black color tone, has a high density, and has excellent storage stability.

Patent Applicant Ricoh Co., Ltd. - Patent Attorney Toshiaki Ikeura Proceedings Amendment September 5, 1980 1, Case Description 1982 Patent Application No. 122579 2, Name of Invention Diazo-based Thermosensitive Recording Material 3 , Relationship to the case of the person making the amendment Patent applicant address 1-3-6 Nakamagome, Ota-ku, Tokyo Name (
674) Ricoh Co., Ltd. - Representative Hama 1) Hiro 4, Agent 〒151 Address 1-58-10-5, Yoyogi, Shibuya-ku, Tokyo, Date of amendment order: Vol. 8, Contents of amendment: In the specification of the present application Make the following corrections.

(1) Page 22, Table 2 is corrected as follows.

“Table-2

Claims (1)

[Claims] (1) A diazo layer containing a diazo compound as a main component and a coupler layer containing a coupler as a main component are laminated on a support, and of the diazo layer and the coupler layer, the layer forming the lower layer is a thermofusible layer. The substance is contained together with a water-insoluble binder, and a black color-forming coupler represented by the following structural formula is used as the coupler. Furthermore, a part of the color-forming system other than the diazo layer has a general formula (wherein R1 is a higher alkyl group). or a hydroxyalkyl group, and R2, R3 and R4 are hydrogen, phenyl, benzyl, alkyl, alkoxy, hydroxyalkyl or cyanoalkyl group. material.