JPS59106994A - Diazo type thermal recording material - Google Patents

Abstract

PURPOSE:To enhance color formability and long-term preservability, by incorporating a water-insoluble binder in a layer for forming a lower layer and a biguanidine compound or an acidic salt thereof in at least one of a diazo layer and a coupler layer. CONSTITUTION:In a diazo type thermal recording material having a heat-sensitive color forming layer having a structure formed by laminating a diazo layer and a coupler layer, a water-insoluble binder is incorporated in a layer for forming a lower layer and a biguanidine compound or an acidic salt thereof is incorporated in at least one of a diazo layer and a coupler layer. A representative biguanidine compound is shown by the formula wherein R1-R6 are each hydrogen, alkyl, cycloalkyl, hydroxy, alkoxy, an aromatic group or a heterocyclic group. By the addition of the biguanidine compound, thermal color forming reaction is remarkably promoted and the above-described laminar structure serves to keep long-term preservability.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a heat-sensitive recording material, particularly a heat-sensitive recording material that can be photofixed. That is, in the present invention, when recording is performed with a thermal head at a certain temperature, color develops, and when further light is irradiated, the color developing ability of the non-printed area disappears.

This invention relates to a diazo heat-sensitive recording material that does not recolor when heated again.

[Prior art]

Thermosensitive recording materials are used as copy paper for books, documents, etc., as well as output recording paper for electronic dividing machines, facsimile machines, medical measuring machines, etc., as well as thermal recording magnetic ticket paper and thermal recording paper. It is also used as paper. In addition, thermosensitive recording materials can be used to record securities, gift certificates, and admission tickets by taking advantage of the ease of automatic recording.

It is also being considered for use as paper for creating certificates, 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 cassiller 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.

By the way, with conventional diazo photosensitive paper, when performing a color reaction, it was possible to use aqueous ammonia or alkaline aqueous solution as a developer and to adopt conditions that would allow a sufficient color reaction to occur, and it was possible to develop the color by heating. It is possible to supply enough heat to carry out reactions. 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,
Since the image forming means used in the case of diazo photosensitive paper cannot be used, various methods are required to efficiently cause a coloring reaction by using less thermal energy.

[Purpose] The present inventors have conducted intensive research to develop a diazo-based heat-sensitive recording material that has high color development and excellent long-term storage stability, unlike the diazo-based heat-sensitive recording materials that have been proposed in the past.As a result, the present invention has been developed. I have reached the point where I have completed the .

〔composition〕

That is, according to the present invention, in a diazo-based heat-sensitive recording material having a heat-sensitive coloring layer having a laminated structure of a diazo layer and a single layer of Cassila, the layer forming the lower layer of the diazo layer and the single layer of coupler is water-insoluble. A diazo-based heat-sensitive recording material is provided, which is characterized in that it contains ingu and at least one of the diazo layer and the coupler layer contains a biguanidine compound or an acid salt thereof.

The biguanidine compound used in the present invention is typically represented by the following general formula.

1 11.31+,' In the above formula, R1-11,6 represents hydrogen, alkyl, cycloalkyl, hydroxy, alkoxy, an aromatic group, or a heterocyclic group. In this case, the alkyl includes lower or higher alkyl, and usually has 1 to 8 carbon atoms.
Among cycloalkyls, cyclohexyl is common; heterocyclic groups include various groups containing heteroatoms such as nitrogen, oxygen, and sulfur; aromatic groups include aryl, aralkyl, and including its substitutes,
Preferably, for example, one expressed by the following equation is listed.

(In the formula, Rii: alkyl, alkoxy, halogen,
(a substituent such as a nitro group, an amine group, etc.) Furthermore, in the general formula, R1 and R2 or R5 and R6 can be connected to each other to form a ring, for example, to form the following cyclic group. be able to.

The above piganidine compound is used as an acid salt 5- However, in this case, as an acid salt.

Examples include inorganic acid salts such as sulfuric acid, hydrochloric acid, carbonic acid, and phosphoric acid, and organic acid salts such as citric acid, tartaric acid, and oxalic acid.

Next, specific examples of the piganidine compound are shown below.

6-NHN1-1 OHO1]20H2NII CNH-CNIT2
・%H2804+111 NHN11 Nrl N11 NTT N11 NHNn 9- lO- The biguanidine compound used in the present invention is a diazo layer and/or
Alternatively, it is added to the coupler layer, but this addition impairs the long-term shelf life of the product, but significantly accelerates the thermal coloring reaction. The reason for this is as follows. That is, this is because the biguanidine compound exhibits strong basicity. However, when used in the layered structure of the present invention, it becomes possible to significantly accelerate the thermochromic reaction without impairing the long-term shelf life of the product. The biguanidine compound can also be contained in other parts of the coloring system, such as the OATSEKO-1 layer and the undercoat layer.

In the heat-sensitive recording material of the present invention, the stacking order of the diazo layer and the cassilla layer is arbitrary, but the layer forming the lower layer preferably contains water-insoluble ζ-ingu together with a thermofusible substance. With this configuration, the lower layer becomes hydrophobic.

The piganidine compound added to the diazo layer and/or the coupler layer is for the diazo compound type 1 meter.

It is used in a proportion of 0.5 to 10 parts by weight, preferably 1 to 10 parts by weight.

The diazo compound and cassiller used in the present invention are those commonly used for diazo photosensitive paper, and examples thereof include those shown below.

Diazo Compound: As the diazo compound used in the present invention, a commonly used diazo compound 1, for example, one represented by the following general formula can be used.

However, in the general formula [+], (:II) and [m], %
R111116r R8 is hydrogen, halogen, C■ to C5
The alkyl group is also hydrogen, halogen s 01 to C5 alkyl group or alkoxyl group, R4 * R5 is the same or different 01 to C5 alkyl group, hydroxyalkyl group, or group or alkoxyl group, or halogen)
, R7 is hydrogen, halogen, trifluoromethyl group, cl
~C5 alkyl group or alkoxyl group, or (
R14+ R+s + pasting 6: same as RI3), Ml, M
2. Ml 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 P-4
, PF'6, and other fluorine-containing inorganic acid ions are preferred. On the other hand, as metal salts that form double salts with respect to acid residues, for example, 71 n Of 2 , C+I Of
21 S n (E I 2, etc.)

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

Specific examples of those corresponding to general formula [l] are:

For example, one can cite the first-order one.

1 14- Specific examples of those corresponding to the general formula Cl1l) are:

For example, one can cite the first-order one.

In the present invention, in order to obtain a product with further improved long-term shelf life, HBF4 and HPF6 are used as the diazo compound.
Advantageously, they are used in the form of water-insoluble salts such as fluorine-containing salts.

Some of the Cassilla used in the present invention include phenol, resorcin, methylresorcin, 4,4-bisresorcin,
Phloroglucin, resorcinic acid.

Phloroglucic acid, 2-methyl-5-methoxy-1,3
-dihydroxybenzene, 5-methoxy-1,3-dihydroxybenzene, 4-N,N-dimethylphenol, 2,6-simethyl-1,3.5-trihydroxy4
Benzoic acid, 2.6-dihydroxybenzoic acid, 2.6-,)
Phenol derivatives such as hydroxy-3,5-dibromo-4-methoxybenzoic acid, α-naphthol, β-naphthol, 4-methoxy-1-naphthol, 2,3-dihydroxynaphthalene, 2,3-dihydroxynaphthalene-
Sodium 6-sulfonate, 2-hydroxy-3-propylmorpholinonaphthoic acid, 2-hydroxy-3-naphtho-
Naphthol derivatives such as 0-toluiside, 2-hydroxy-3-naphthoic acid morpholinozolobylamide, naphthol derivatives, acetoacetanilide & 4-benzoylamino-2,5-jethoxyacetoacetanilide, N-
Acetoacetooctadecylamine, N,N'-bis(acetoaceto)decane-1,10-diamine, 2,4.6
Examples include active methylene compounds such as -dribromoacetoacetanilide, but of course the present invention is not limited to these compounds, and any compound that can act as a cassiller on the diazo compound can be used.

In the present invention, thermofusible substances are preferably used in order to enhance rapid color development. A specific example of such a 17- is, for example, a first-order one.

Alcohol derivatives such as 2-tribromoethanol, 2.2-cumethyltrimethylene glycol, 1.2-cyclohexane, fall, acid derivatives such as malonic acid, glutaric acid, maleic acid, methylmaleic acid, beeswax, shellac wax animal waxes such as carnano wax, vegetable waxes such as carnano wax, mineral waxes such as montan wax, petroleum waxes such as chisel rough wax, microcrystalline wax, and other synthetic waxes such as polyhydric alcohols of higher fatty acids. Esters, higher amines, higher amides.

Condensates of fatty acids and amines, condensates of aromatics and amines 1
Synthetic paraffin, nografine chloride, metal salts of higher fatty acids, higher linear glycols, dialkyl 3,4-epoxyhexahydrophthalate, etc.

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

If the melting point or softening point is less than 50C, the shelf life of the product tends to deteriorate, and if it exceeds 250 18-C, the thermal response of the product to the thermal head becomes unsatisfactory. ! From the viewpoint of obtaining a product with high-speed color development (high-speed recording), these thermofusible substances used in the present invention should be added in an amount of 1 to 1 part by weight of the diazo compound.
It is used in an amount of 30 parts by weight, preferably 2 to 10 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 it in a proportion of 2 parts by weight or more for high-speed output recording devices such as 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 or thermosoftening substance added is preferably kept within the above range.

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 for rainproofing the 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.

Filler: A filler is added to improve the matching property with the thermal spatula P when heated with a thermal head etc. Such fillers include, for example, the following t[
There is something.

Styrene resin particles, urea-formalin condensate resin particles, aluminum hydroxide, magnesium hydroxide, calcium carbonate, titanium, talc, kaolin, silica, alumina, etc., and inorganic solid particles.

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

Nlubitol, saccharose, etc. are used.

In the present invention, the water-insoluble binder (binder) used to make the diazo layer or cassilla layer forming the lower layer a hydrophobic layer includes polyester, polystyrene, chloride-me, polyvinyl acetate, polyvinyl acetate, Vinyl chloride, polybutadiene, polyacrylic acid ester, vinyl chloride/vinyl acetate copolymer, polybutadiene, styrene/citadiene/acrylic copolymer, polyethylene, ethylene/vinyl acetate copolymer, styrene/acrylic copolymer, polyvinylidene chloride , vinylidene chloride/acrylic copolymer,
Organic solvent-soluble or water-dispersible resins such as phenol resins, urea/formalin resins, and melamine resins can be used.

In addition to the above-mentioned organic solvent-soluble or water-dispersible resins, examples of binders used in other layers include polyvinyl alcohol, polyacrylamide, starch, gelatin, starch and its derivatives, polyvinylpyrrolidone, and cardil. Water-soluble resins such as oxymethylcellulose, methylcellulose, ethylcellulose, styrene-maleic anhydride copolymer, iso(or diiso)butylene-maleic anhydride copolymer, etc. can also be used.

In the present invention, the solvent for dissolving or dispersing the components forming one layer 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 prepared by dissolving an organic solvent in water, benzene, toluene, xylene, n-hexane, n-hebutane, cyclohexane,
Nonpolar organic solvents such as kerosene, methyl isobutyl ketone, methyl cellosolve, acetone, methyl ethyl ketone, dimethyl ether, and other rod organic solvents may be used.

The supports used in the present invention include paper, synthetic paper, plastic film, and paper precoated with synthetic resin, filler, etc., and the like.

〔effect〕

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 22- The characters and images recorded on the film can be fixed by forming the image by heating and then decomposing the unreacted diazo compound by light and heat. It's Kade.

The heat-sensitive recording material of the present invention can be applied to record necessary information on securities, gift certificates, admission tickets, certificates, slips, etc., and to create them, by taking advantage of its fixing properties. Moreover, since the heat-sensitive recording material of the present invention has the above-mentioned special layer structure, it has extremely excellent long-term storage stability and thermal color development.

〔Example〕

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

Examples 1 to 3 (Liquid A) Styrene-acrylic copolymer 40 parts by weight water
35 (Liquid B) N-stearylbenzamide 15
Vinyl chloride-vinyl acetate copolymer 20〃M
EK (methyl ethyl ketone) 6o (C
Liquid) Naphthol A8 10 parts by weight Zinc stearate 20 // Vinylidene chloride-acrylic copolymer 40 u water
30 (Liquid D) Phloroglucin 10 parts by weight Calcium carbonate (light) 2o Polyvinyl alcohol 1o Water
50 parts by weight (H solution) Silica (Thyroid 244) 1o Methylcellulose 1o Water
60〃(H liquid) Silica (Thyroid 65) 1Ou-
Rivinyl alcohol 5 Water
75 〃 25- (Liquid G) A liquid obtained by removing the biguaninone compound from (Liquid D).

(Liquid H) A solution in which urea is used instead of the piganidine compound in (Liquid H).

(■liquid) A liquid obtained by removing the biguanidine compound from (Liquid H).

The above ingredients were pulverized for 24 hours using a Zeel mill.

Dispersions were prepared to prepare dispersion liquids A to ①.

As shown in Table 1 above, Examples 1 to 3. Each coating solution with the contents of Comparative Examples 1 to 3 was applied to 26" double-quality paper (approximately 50 g/m").
- A heat-sensitive layer was formed by coating and drying on the surface, each layer having an adhesion amount of 2 to 3 g (solid content), and further calendering to obtain a heat-sensitive recording material with Bekk smoothness of 500 seconds.

Refax 3 the heat-sensitive recording material obtained as above.
300 (manufactured by Ricoh) in G-111 mode, and was then completely exposed and fixed using Ricoh HiStart 205 (manufactured by Ricoh).

Next, the quality comparison of Examples 1 to 3 and Comparative Examples 1 to 3 is shown in Table 2.
Shown below.

Mura Density Gauge This is the value measured by the print density of the G-111 mode of the FAX 3300 using a Max4x densitometer (l(D-514)).

The skin density on the mountain pass is the value measured with a mask densitometer (T1.r)-51/I) after completely exposing the diazo compound to light. be.

■Preservation stability is determined by preparing the coating solution, immediately applying it, leaving the dried sample in a dark place at a temperature of 4 oct and 90% RH for 24 hours, then completely exposing the diazo compound to light, and then using a Maquis densitometer (RD- 514).

From the results shown in Cloth-2 above, it can be seen that the product of the present invention has significantly improved thermal coloring properties without impairing storage stability and texture density.

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

Claims (1)

[Claims] (1)-) Among the diazo layer and the cassilla layer in a diazo thermosensitive recording material having a thermosensitive coloring layer having a laminated structure of an azo layer and a coupler layer. A diazo-based heat-sensitive recording material, characterized in that the layer forming the lower layer contains a water-insoluble inder, and at least one of the diazo layer and the cassilla layer contains a biguanidine compound or an acid salt thereof.