JPS5831792A - Diazo-based heat-sensitive recording material - Google Patents

Abstract

PURPOSE:To improve the long-term storability of a diazo-based heat-sensitive recording material by adding a quaternary ammonium salt to a heat-sensive color-forming layer. CONSTITUTION:A quaternary ammonium salt of the formula (where R<1>-R4 are each an alkyl, cycloalkyl, alkenyl, aryl, or aralkyl and X is an acid anion, particularly chlorine) is added to a heat-sensitive layer containing a diazo compound, a coupler, and a heat-fusible substance as main components. The quaternary ammonium salts used include tetramethylammonium chloride, tetraamylammonium bromide, etc. By adding about 2-30pts.wt. heat-softening substance of a melting point (or softening point) of about 50-250 deg.C on the basis of 1pt.wt. diazo compound to the heat-sensitive layer, the high-temperature coloring property of the recording material can be improved and the occurrence of bleeding during the thermal coloring process can be prevented.

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 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 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 conducted extensive research in order to develop a material that, unlike conventional diazo-based heat-sensitive recording materials, has excellent thermal responsiveness to thermal heads for high-speed recording, as well as excellent long-term storage stability. As a result, the present invention was completed.

That is, according to the present invention, in a heat-sensitive recording material provided with a heat-sensitive layer mainly composed of a diazo compound, a coupler, and a heat-fusible substance, a quaternary ammonium salt is contained in the heat-sensitive coloring layer. A diazo-based heat-sensitive recording material with characteristics is provided.

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 quaternary ammonium salt is used as an additive component to the heat-sensitive coloring layer in order to improve storage stability. This quaternary ammonium salt is represented by the following general formula.

In the Mayuki formula, Bl to R4 are an alkyl group, a cycloalkyl group, an alkenyl group, an aryl group, or an aralkyl group;
is the anion of the acid. In this case, halogen, particularly chlorine, is preferred as the anion.

Specific examples of quaternary ammonium salts include the following.

Tetramethylammonium chloride, tetraethylammonium chloride, tetraamylammonium bromide, mono-benzyltrimethylammonium chloride, mono-benzyltriethylammonium chloride, seven-benzyltriphenylammonium chloride.

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 commonly used diazo compound, for example, one represented by the following general formula is used.

R3B.

/ 9 However, in the general formula (0, [1 and [moan], Ryu, R,
,R.

halogen, halogen, alkyl group or alkoxyl group of 01-05, R4* R8 is the same or different 01-05
or alkoxyl group, or halogen), R7 is hydrogen, halogen, trifluoromethyl group, 01~Os("1
4 e ILts l axs "same as 1B), '1
e'* + 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 and BP;
It is preferable to use a fluorine-containing inorganic acid such as pi.Metal salts that form double salts with acid residues include, for example, ZnO2, 0d04, and 8n04. Y
represents -OH- or -CO-, and n is 0 or 0.

Specific examples of compounds corresponding to general formula [1]K include the following.

0H3 00,H.

08s 00,H.

General formula [Specific examples of things that fall under phantom are, for example,
The following can be mentioned:

t Specific examples of those corresponding to general formula (4) include the following.

00,H.

002H.

In the present invention, in order to obtain a product with further improved long-term 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.

Katsupura m: Couplers used in the present invention include phenol, resorcinol, methylresorcinol, 4,4-bisresorcinol, phloroglucinol, resorcinic acid, phloroglucic acid,
2-methyl-5-methoxy-1,3-dihydroxybenzene, 5-methoxy-1,3-dihydroxybenzene,
4-N,N-dimethylphenol, 2,6-dimethyl-
Phenol derivatives such as 1+3#5-trihydroxybenzene, 2,6-dihydroxybenzoic acid, 2,6-cyhydroxy-3,5-dibromo-4-methoxybenzoic acid,
α-naphthol, I-naphthol, 4-methoxy-1-
naphthol, 2,3-hydroxynaphthalene, 2,3-
Sodium dihydroxynaphthalene-6-sulfonate, 2-
Hydroxy-3-propylmorpholinonaphthoic acid, 2-
Examples include 7-tolyl derivatives such as hydroxy-3-naphtho-0-toluicide and 2-hydroxy-3-s7tolic acid morpholinopropylamide, but of course, the compounds are limited to these. Rather, any substance that can act as a coupler for the diazo compound can be applied.

In the present invention, in order to achieve the intended purpose, components consisting of a diazo compound, a coupler, a quaternary ammonium salt, and a thermofusible substance are added in one layer or separately to form a thermosensitive coloring layer. It is necessary to form them as layers on a support, and at least one of the layers to contain a relatively large amount of thermofusible material. As such a thermofusible substance, one having a melting point or softening point in the range of 50 to 250C is used. Specific examples 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 waxes, 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 straight chain glycols, dialkyl 3,4-epoxyhexahydrophthalate, etc.

The thermofusible or thermosoftening 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 decrease, and if it exceeds 250C, 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 or thermosoftening substances used in the present invention should be used in an amount of 2 to 3 parts by weight per 1 part by weight of the diazo compound.
0 parts by weight, preferably 5 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 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 material added is preferably kept within the above range.

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, polyacrylate, polystyrene/, polyptadier/, polyacrylamide, styrene/
Examples include butadiene/acrylic copolymers. These binders preferably have a melting point or softening point in the range of 50 to 250C.

In the present invention, as described above, by making the heat-fusible substance and the heat-fusible or heat-softening binder exist in the heat-sensitive coloring layer, the coloring reaction between the diazo compound and the coupler is controlled. Color develops with the minimum thermal energy required for reaction, ensuring high-speed color development.

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, sulfuric acid, etc.

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.

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.

As other auxiliary ingredients, zinc chloride, zinc sulfate, sodium citrate, guanidine sulfate, calcium gluconate, sorbitol, saccharose, etc. are used to suppress or assist color development.

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 the layer is Other binders may be used in combination to firmly bind to the support. Examples of such binders include the following.

Polyvinyl alcohol, polyacrylamide, casein, gelatin, starch and its derivatives, polyvinylpyrrolidone, carboxymethylcellulose 1, methylcellulose, ethylcellulose, polyester (MW-i=i
00,000 or more), polystyrene (vw = 10,000 or more), chlorinated rubber, styrene-maleic anhydride copolymer, iso(or diiso)butylene-maleic anhydride copolymer, urea-formalin resin, phenol resin, melamine resin water-soluble, organic solvent-soluble, or water-based dispersion resins.

These binders can also be used alone depending on the case.

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 coated on a support and dried. 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 in which an organic solvent is dissolved in water, benzene,
Examples include non-polar or polar organic solvents such as toluene, xylene, n-hexane, n-hebutane, cyclohexa/, kerosene, methyl isobutyl keto/, methyl cellosolve, acetone, methyl ethyl ketone, dimethyl ether, and siloxane. .

The thermosensitive coloring layer formed in the present invention has a single-layer structure or a multi-layer laminated structure, and in this case, the diazo compound and the coupler are contained in the layer as either discontinuous particles or continuous particles. It may exist in any state. In this case, "discontinuous particles" are obtained when forming a layer using a dispersion in which a diazo compound or a coupler is dispersed as insoluble solid particles in a solvent.
"Continuous particles" refers to the state of existence of these reactive components in a layer, and "continuous particles" are obtained when a layer is formed using a solution in which a diazo compound or coupler is dissolved in a solvent. , refers to the state of existence of these reactive components in the layer.

In the present invention, in order to obtain a product with balanced thermal color development and storage stability, it is preferred that one of the diazo compound layer and the coupler layer be a discontinuous particle layer, and the other be a continuous particle layer. If both of them are discontinuous particle layers, the thermal coloring property tends to decrease, while if both of them are continuous particle layers, the thermal coloring property tends to be too large and the storage stability tends to decrease.

However, no matter which type of heat-sensitive coloring layer is used,
By containing a quaternary ammonium salt in the heat-sensitive coloring layer, storage stability is significantly improved.

The amount of the quaternary ammonium salt to be used is preferably 1 to 20 parts by weight, preferably 5 to 15 parts by weight, per 1 part by weight of the diazo compound. If the amount is less than 1 part by weight, the improvement in storage stability will be insufficient, and if it exceeds 20 parts by weight, the color development will be unsatisfactory.

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 forming a multi-image 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 using examples.

Example [Liquid A] 2,6-cyhydroxy-3,4-dibrome 5 #
-4-Methoxybenzoic acid calcium gluconate 3I Stearic acid amide 20I Guanidine sulfate 3I Silica 3 # Tetramethylammonium chloride 15 1 Carboxyl group modified polyvinyl 201 Alcohol (10% aqueous solution) (Itaconic acid modified product) Water 19
- After dispersing the above composition for 24 hours using a ball mill, polyvinyl acetate emulsion (solid content 50%) 10
Parts by weight were added and stirred until homogeneous to prepare a dispersion liquid A.

[Liquid B]

JP-A-58-31792 (6) Phloroglucin 5 parts by weight N-octadecyl(4-methoxycarboxyl)benzamidetetraethylammonium chloride 25#
Calcium carbonate 21 Polyvinyl alcohol (lo% water soluble 1ffl) 25 #Water 28
/The above composition was dispersed for 24 hours using a ball mill to prepare dispersion liquid B.

Stearic acid amide 5I Boristivy resin (MW=i=1000) 3 #Mono-bensyl, triethylamsonium 51 chloride cyclohexane 85N The above composition was dispersed for 24 hours using a ball mill to prepare a dispersion liquid O. did.

[Liquid D]

Mono-benzyl from the liquid c. A dispersion liquid excluding triethylammonium chloride was prepared.

Comparative Example [Liquid E] A dispersion liquid B was prepared by removing tetramethylammonium chloride from the liquid A.

[F liquid]

A dispersion liquid F was prepared by removing tetraethylammonium chloride from the liquid -B.

The A-P solutions prepared as described above were applied in the combinations shown in Table 1, and the cans were applied onto high-quality paper (approximately 501/lr?), dried, and further calendered to a Beck smoothness of 400.
A diazo-based heat-sensitive recording material was prepared.

[The adhesion amount of the can liquid is 1.0 to 3.011/rrl (solid content)] Table 1 Using the heat-sensitive recording material obtained as above as a sample,
After printing in Refax 303 [■Made by Ricoh] in #)G-■ mode, Ricoh High Start type 4 [Manufactured by Ricoh]
It was fully exposed and fixed.

These materials did not develop color even when reheated, and the images did not disappear when exposed to organic solvents.

Next, the heat-sensitive recording material obtained above was tested for color density and storage stability. The results are shown in Table-2.

The solid print density of the color density gauge fax 303 in the GI mode was measured using a Macbeth densitometer (RD-514). In addition, the storage stability of the sample is measured at a temperature of 40C and a humidity of 90C.
% TLH in a dark place for 24 hours to perform a forced deterioration test, and the skin density before and after the test was measured.

In this case, a Macbeth densitometer was used for concentration measurement. If the background density value is 0.20 or less, it is confirmed that the heat-sensitive recording material has a shelf life of 2 years or more when stored in a dark place at room temperature and humidity.

Table 2 From the above results, it can be seen that the products of the present invention are clearly satisfactory in storage, warping, and heat response.

September 1980, Commissioner of the Japan Patent Office Shima 1) Tonoro Haruki 1, Indication of the case 1982 Patent Application No. 1301-2 1, Title of the invention Diary-based thermal recorder - Materials & Amendment case Related Patent Applicant Address: 1-3-6 Nakamagome, Ota-ku, Tokyo Name (Name) (674) Ricoh Co., Ltd. Representative: Takeshi Takemoto, representative of Ricoh Co., Ltd.

None) Harukasu

Claims (1)

[Claims] (1) In a heat-sensitive recording material provided with a heat-sensitive layer mainly composed of a diazo compound, a coupler, and a heat-fusible substance,
A diazo-based heat-sensitive recording material, characterized in that the heat-sensitive coloring layer contains a quaternary ammonium salt.