JPS5855286A - Diazo heat-sensitive recording material - Google Patents

Abstract

PURPOSE:To obtain a diazo heat-sensitive recording material capable of high- speed recording and having excellent heat respondency and good long-term sto- rability by forming a laminated heat-sensitive coloring layer consisting of a diazo compound-containing layer and a coupler-containing layer, to which is added a heat-meltable substance under a specific condition, on a supporter. CONSTITUTION:A heat-sensitive coloring layer is formed on a supporter by laminating in any order a diazo compound-containing layer and a coupler (e.g., phenol, etc.) containing layer, at least one of which contains a heat-meltable substance (e.g., polyvinyl acetate, etc.), in such a way that the amount of solid component to be contained in any one (on the lower side) of the diazo compound-containing layer and the coupler-containing layer is kept in at least 70wt% of all solid components in the heat-sensitive coloring layer. Also, an acid substance, a basic substance, a filler, etc., as auxiliary substances are preferably added to the heat-sensitive coloring layer.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a heat-sensitive recording material, particularly a heat-sensitive recording material that can be photofixed. That is, the present invention relates to a diazo-based thermosensitive recording material that develops color when recorded with a thermal head at a certain temperature, loses its ability to develop color in non-printed areas when further irradiated with light, and does not recolor when heat is applied again. It is.

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 are also being considered for use as paper for creating securities, gift certificates, admission tickets, certificates, slips, etc. by taking advantage of their ease of automatic recording. In order to obtain high recording reliability, the heat-sensitive recording material must be able to be fixed.

Conventionally, as heat-sensitive recording materials that can be fixed, diazo-based materials that utilize a color-forming reaction between a diazo compound and a coupler are known. However, from the standpoint of practicality, conventional products have not yet been satisfactory in terms of thermal response to thermal heads and long-term storage stability.

In particular, in fields such as facsimile, there is a strong demand for high-speed recording performance (high-speed color development) in order to reduce information transmission costs, but conventional diazo-based products still cannot adequately meet these requirements. It didn't satisfy me.

The present inventors have undertaken research to develop a material that, unlike conventional diazo-based thermosensitive recording materials, has excellent thermal response to heat and rad for high-speed recording, as well as excellent long-term storage stability. As a result of repeated efforts, the present invention was completed.

That is, according to the present invention, a heat-sensitive coloring layer is formed by laminating a diazo compound-containing layer and a coupler-containing layer on a support in any order, with at least one of these layers containing a thermofusible substance. At the same time, the solid content in the layer forming the lower layer of the diazo compound-containing layer and the coupler-containing layer is reduced to at least 7% of the total solid content in the heat-sensitive coloring layer.
A diazo-based heat-sensitive recording material is provided, which is characterized in that the diazo-based heat-sensitive recording material is maintained at 0% by weight.

In the present invention, the solid content refers to the components of the coating solution excluding the solvent, that is, the components remaining on the support when the coating solution is applied to the support and dried, and includes diazo compounds, In addition to couplers and thermofusible substances, auxiliary additive components such as fillers and binders are included.

In the present invention, it is adjusted to be included in the layer forming the lower layer of the diazo compound-containing layer and the Katzfurer-containing layer. By adjusting the solid content of the upper and lower layers in the heat-sensitive coloring layer, the heat-sensitive coloring layer used in the present invention has a two-layer structure, but it has a one-layer structure similar to that of a conventional two-layer structure. Compared to other products, high color development is ensured, and furthermore, the progress of color development during storage is suppressed over a long period of time.

High storage stability is ensured.

The diazo compound and coupler used in the present invention are those commonly used in diazo photosensitive paper, and include, for example, those shown below.
[Diazo Compound] As the diazo compound used in the present invention, a conventional one, for example, one represented by the following general formula is used.

几9 However, in the general formulas (1), (II) and [lll, l, R1+R91i water , hydroxyalkyl group, or alkoxyl group, or halogen),
Ry hydrogen, halogen, trifluoromethyl group, 0. ~
The alkyl group or alkoxyl group of C6 is or (R
I4 t R+5 t R16: Same as J'L13),
MIIM2νM3 is an acid residue or an acid residue forming a double salt with a metal salt.

In this case, the acid residues include norogen ion, BF, -
Fluorine-containing inorganic acid ions such as 1PF6- are preferable, while examples of metal salts that form double salts with acid residues include -ZnO/2gCdC72t 5nOJ2. Y represents -CH2- or -CO-, and n is O or 1.

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

U IJ 2 M 5 00H3 Specific examples of those corresponding to general formula (It) include the following.

Specific examples of compounds corresponding to the general formula Cl1l) include the following.

CI! 00,H.

In the present invention, in order to obtain a product with further improved long-term shelf life, -BF is used 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 or -PF.

Katsupura m: Couplers used in the present invention include phenol, resorcin, methylresorcin, 4v4-bisresorcin,
Phloroglucinic acid, phloroglucinic acid, 2
-Methyl-5-methoxy-1s3''2hydroxybenzene, 5-methoxy-]13-dihydroxybenzene, 4
NsN-dimethylphenol, 2y6-dimethyl-1t
3t5-trihydroxybenzene, 216-dihydroxybenzoic acid, 296-cyhydroxy-395-dibromo-4-methoxybenzoic acid and other heptanols derivatives, a-
Naphthol, β-naphthol, 4-methoxy-1-naphthol, 213-hydroxyphthalene, 223-dihydroxynaphthalene-sodium sulfonate, 2-hydroxy-3-pouvyl morborinonaphthoic acid, 2-hydrotsuru sea 3 -naphtho-0-)luidide, 2-hydroxy-3
Examples include naphthol derivatives such as -naphthoic acid morpholinopropylamide, but of course the present invention is not limited to these, and any compound that can act as a coupler for the diazo compound can be used.

Examples of the thermofusible substances used in the present invention include the following.

2-) Alcohol derivatives such as IJ 7'' romethanol, 2t2-dimethyltrimethylene glycol, 12-cyclohexanediol, malonic acid, glutaric acid,
Acid derivatives such as maleic acid and methylmaleic acid, beeswax,
Animal waxes such as shellac wax, vegetable waxes such as carnauba wax, mineral waxes such as montan wax, petroleum waxes such as paraffin wax and microcrystalline wax, and 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 paraffins, metal salts of higher fatty acids, higher linear glycols, dialkyl 394-epoxyhexahydrophthalates, and the like.

The thermofusible substance used in the present invention preferably has a melting point and a softening point of 50 to 250°C. If the melting point or softening temperature is less than 50°C, the shelf life of the product tends to decrease, and if it reaches 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 10 parts by weight, per 1 part by weight of the diazo compound. Used in 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 facsimile. On the other hand, if the amount added is too large, images may blur when heated and colored.

In the present invention, in order to firmly support the heat-sensitive coloring layer on the support, a heat-fusible or heat-softening binder is used as necessary, and such binders include, for example: Polyvinyl acetate, polyvinyl chloride, vinyl chloride/vinyl acetate copolymer, polyacrylic acid ester, polystyrene, polybutadiene, polyacrylamide, methylene resin/
Examples include butadiene/acrylic copolymers. These binders preferably have a melting point or softening point in the range of 50 to 250°C.

In the present invention, as the binder, thermofusible or thermosoftening binders as described above are preferably used, but these binders do not necessarily need to be used alone, and each component in one layer is Other binders may be used in combination to firmly bind to the support. Examples of such a binder include primary binders.

Polyvinyl alcohol, polyacrylamide, casein, gelatin, starch and its derivatives, polyvinylpyrrolidone, carboxymethylcellulose, methylcellulose, ethylcellulose, polyester (100,000 or more in MW), polystyrene (100,000 or more in MW), chlorinated rubber,
Water-soluble, organic solvent-soluble, or water-dispersed resins such as styrene-maleic anhydride copolymer, iso(or diiso)butylene-maleic anhydride copolymer, urea-polmarine resin, phenol resin, melamine resin.

Of course, these binders can be used alone depending on the case.

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.

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

such as sulfuric acid.

Basic substance: A basic substance is added as necessary to cause a coupling reaction during heating, and includes, for example, a primary substance.

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

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 with a thermal head, etc., and examples of such fillers include the following.

Organic and inorganic solid particles such as rum, calcium carbonate, titanium, talc, kaolin, silica, alumina, etc.

Other auxiliary ingredients include zinc chloride, zinc sulfate, sodium citrate, guanidine sulfate, and calcium gluconate to suppress or assist color development.

Sorbitol, sucrose, etc. are used.

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

In the present invention, the total solid content supported on the support is 1 to
10 f/m2, 70% or more of that, preferably 80
Adjust so that % or more is included in the lower layer. The present invention is particularly effective in using phloroglucin as a coupler.

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 with light.

Further, the heat-sensitive recording material of the present invention utilizes its fixing properties,
It can be applied to recording and creating necessary information for securities, gift certificates, admission tickets, certificates, slips, etc.

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

Examples 1-2 [Liquid A] Citric acid 1 "Polyvinyl alcohol (10% aqueous solution) 5.

Ta.

[Liquid B]

Phloroglucin 5 parts by weight
lO Thiourea
5 Polyester (MWW18
O4910//n-hexane 50
[Liquid C] Phloroglucin 5 parts by weight Sake Stone
Acid 1 part by weight polyvinyl acetate emulsion (50% li form 1 1 //
Ta.

[Liquid D]

Stearic acid amide 20 Styrene resin filler 5 Urea
5 Polystyrene (800 in vW, 80°C in softening point) 10 Cyclohexane 57 [Liquid E] Citric acid 1 Silica
1o N-octadecyl (4-hakidicarbonyl) 2o.

Benzamide 10% polyvinyl alcohol aqueous solution 2 o water
54 〃[F
Liquid] Phloroglucin 5 parts by weight Thionidine 5.

Polyester (MWW18O4910ttn-Hexane f3Q // [Liquid G] According to the contents of Example 1ν2 and Comparative Example 1-2 shown in Table 1, each coating solution was applied to the surface of high-quality paper (approximately soy/m) and dried. A heat-sensitive recording material 4 was obtained by laminating layers having an adhesion amount of 0.5 to 7 m'' (solid content) and further calendering to obtain a Bekk smoothness of 500 seconds.

The heat-sensitive recording material obtained in the above manner is refaxed to
3 (manufactured by Ricoh Co., Ltd.) in G-11 mode, and then completely exposed and fixed with Ricovino Istart 20s C@) (manufactured by Ricoh).

Next, Table 2 shows a quality comparison between Example 1>2 and Comparative Example 1120.

Table-2 *1 Print density in G-■ mode of Density Gauge Fax 303 Value measured with Macbeth RD-514 *2 For background density, adjust the coating liquid, apply it directly, dry it, and completely expose the diazo to light. The value was then measured using a Macbeth densitometer RD-514.

*3 Storage stability is determined by preparing the coating solution, applying it directly, leaving the dried sample in a dark place at 40°C and 90% RH for 24 hours, fully exposing the diazo to light, and using a Macbeth densitometer 1'
Value measured with LD-514.

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

Claims (1)

[Claims] (1) A diazo compound-containing layer and a coupler-containing layer are laminated in any order on a support, with at least one of these layers containing a thermofusible substance to form a thermosensitive coloring layer, and a diazo compound-containing layer is laminated in any order on a support. A diazo thermosensitive recording material characterized in that the solid content contained in the layer forming the lower layer among the layers and the coupler-containing layer is maintained at at least 70% by weight of the total solid content in the thermosensitive coloring layer.