JPS581590A - Diazo heat-sensitive recording material - Google Patents

Abstract

PURPOSE:To provide a fixable recording material which is suitable for securities and the like with excellent thermal response and long-term preservability, by laminating a layer of a specified diazo compound and that of phloroglucinol separately on a support. CONSTITUTION:For example, one or more of diazo compounds of the formula (where R1-R3 represent each H, lower alkyl, lower alkoxy or halogen, n is 0 or 1 and x is an acid residue which is free or forming a double salt with a metal salt) and phloroglucinol as a coupler are dissolved or dispersed in separate solvents (e.g., benzene) while 2-30pts.wt. (per pt.wt. of the component A) heat-fusible or heat-softening material (e.g., stear amide) is added to either of them to prepare a coating liquid for lamination. The two liquid are applied sequentially in layers on a support and dried to obtain a recording material as expected.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a heat-sensitive recording material, and more particularly to a fixable diazo heat-sensitive recording material.

Conventionally, as heat-sensitive recording materials, there are those that produce heat-sensitive coloring by utilizing the reaction between organic metal salts and reducing agents, and those that produce heat-sensitive coloring by using the reaction between leuco dyes and acidic substances. ing. However, such heat-sensitive recording materials have the disadvantage that recorded images cannot be fixed because they are non-fixable. That is,
In the case of such a non-fixable heat-sensitive recording material, it is possible to perform recording again by performing another heating printing after performing recording once by heating printing.

Therefore, the heat-sensitive recording materials described above have low reliability because the information recorded on them can be falsified later. It could not be applied to recording necessary information on documents, slips, etc., or to creating them.

In addition, in the case of such recording materials, generally 7 ocl
When exposed to the environment above, the entire surface becomes colored, causing the problem that the records become illegible. In particular, heat-sensitive recording materials that utilize the reaction between leuco dyes and acidic substances have the disadvantage that recorded information is erased when they come into contact with organic solvents or plasticizers in plastics. These drawbacks are due to the fact that these heat-sensitive recording materials are non-fixable.

On the other hand, so-called diazo photosensitive paper, which utilizes the reaction between a diazo compound and a coupler, is widely known as a fixable recording material. In this diazo photosensitive paper, by irradiating the unreacted diazo compound with light after image formation, it can be photodecomposed and fixed.

Conventionally, heat-sensitive recording materials have been known in which the reaction between a diazo compound and a coupler is carried out by heating. This diazo-based heat-sensitive recording material has a heat-sensitive recording material containing a diazo compound and its coupler as the main reaction components on a support.
Among the components in the heat-sensitive recording layer, any one component is isolated from other components as discontinuous particles to prevent the coloring reaction from proceeding. However, all of the conventional ones are still insufficient in terms of storage stability and thermal coloring properties when viewed from a practical standpoint. For example, in order to obtain a product with a high shelf life, it has been proposed to laminate a diazo compound and a coupler as separate layers, but in this case, the shelf life is relatively good, but the color development This is still unsatisfactory in this respect, and images with high color development cannot be obtained by instantaneous heating.

Recently, heat-sensitive recording materials such as facmilly, telex,
There is a strong demand for high-speed recording properties so that they can be used as recording materials for output from electronic computers, medical measuring instruments, and the like. In particular, in the field of facsimile, heat-sensitive recording properties that are compatible with high-speed printing are required in order to reduce information transmission costs. Diazo-based heat-sensitive recording materials have the advantage of being fixable, but when applied to such uses, conventional ones have the disadvantage of insufficient thermal responsiveness to thermal heads. .

The present inventors have overcome the above-mentioned drawbacks of conventionally proposed diazo-based thermal recording materials, and have developed a diazo-based thermal recording material having a two-layer type thermal recording layer that has sufficient thermal responsiveness to a thermal head. As a result of intensive research to develop a product that also has excellent long-term storage stability, the present invention has been completed.

That is, according to the present invention, at least one diazo compound selected from diazo compounds represented by the following general formula 0) and phloroglucin as its coupler are laminated on a support as separate layers. A diazo thermosensitive recording material capable of high-speed recording with characteristics is provided.

General formula (I) 2 In the above formula, R1+ R2 and R3 are hydrogen, lower alkyl group, lower alkoxy group, or halogen; n is an integer of 0 or 1; It is an acid residue. In this case, the acid residue is preferably a halogen ion or an anion of a fluoric acid 6- such as BF4 or PFii, while a metal salt that forms a double salt with the acid residue is , for example, ZnCl2,
Examples include CdCl2.5nQI2. In the present invention,
In order to obtain a product with good long-term storage stability, the acid residue X is preferably a water-insoluble salt-forming acid residue, for example, an anion of a fluoric acid such as BF4- or PF6-.

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

In the present invention, in order to achieve the intended purpose, the diazo compound represented by the general formula (1) is selected as the diazo compound to be contained in the heat-sensitive coloring layer, and phloroglucin is selected as the coupler thereof. All of these reactive components are laminated as separate layers on the support to form a thermosensitive coloring layer, and if necessary, at least one of the layers contains a relatively large amount of thermofusible material. It is necessary to contain the substance. With such a configuration,
It is possible to obtain a heat-sensitive recording material that has significantly higher color development and properties than conventional diazo-based heat-sensitive recording materials, can develop color by instantaneous heating (high-speed recording performance), and has excellent long-term storage stability. can.

In the present invention, the diazo compound layer and/or the phloroglucin layer further facilitates the coloring reaction during heating (
It is preferable to add a thermofusible substance to enable rapid color development. Specific examples of such things include, for example, the following: In the present invention, those having a melting point or softening point in a range of 50 to 250C are used.

Alcohol derivatives such as 2-tribromoethanol, 2,2-diethyltrimethylene glycol, l, 2-7 chlorohexanediol, acid derivatives such as malonic acid, curtaric acid, maleic acid, methylmaleic acid, beeswax, shellac wax animal waxes such as carnauba wax, vegetable waxes such as carnauba wax, mineral waxes such as montan wax, petroleum waxes such as halafine 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, 3,4--9 = Epoquin hexaphthal dialkyl acids, etc.

In the present invention, these thermofusible substances are 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, the effect of improving color development will be reduced. In the case of the present invention, for high-speed output recording such as facsimile,
In particular, it is preferable to use it in a proportion of 5 parts by weight or more. 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.

In the present invention, a binder is used to bind each component in the layer to each other and to stably support each layer on the support. Regarding this binder, in the case of the present invention, it is preferable to use one that melts or softens at a temperature of 50 to 250C. When such a heat-fusible or heat-softening substance is used as a binder, this binder is also used together with the heat-fusible or heat-softening substance used as an added component in the layer during color development by heating. Since it melts or softens at the same time, it is possible to obtain a product with even higher thermochromic properties. Like this 10
- Examples of thermofusible or thermosoftening binders include the following.

Polyvinyl acetate, polyvinyl chloride, vinyl chloride/vinyl acetate copolymer, polystyrene, polyester, styrene/butadiene/acrylic copolymer, polyacrylic ester, polyacrylamide, polymethacrylic ester, polybutadiene, etc.

Further, in the case of the present invention, such a thermofusible or thermosoftening binder does not necessarily need to be used alone, and is usually used in order to more firmly bind each component in the layer to the support. 3
A heat-resistant binder may also be used in a proportion not exceeding 0% by weight.

Examples of such binders include those shown below. Of course, in the present invention, such a heat-retardant substance can also be used alone.

Polyvinyl alcohol, polyacrylamide, casein, gelatin, starch and its derivatives, polyvinylpyrrolidone, carboxymethylcellulose, methylcellulose, ethylcellulose, chlorinated rubber, polystyrene (MW
: 100,000 or more), water-soluble, organic solvent-soluble, water-based dispersion resins such as polyurethane, urea-formalin resin, phenol resin, etc.

Further, in the present invention, the diazo compound layer and/or the Florodal 77 layer may contain acidic substances, basic substances, fillers, and other substances as auxiliary components as 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 further promote the 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 with the thermal head when heated by a thermal head, etc., and examples of such fillers include the following.

Organic and inorganic solid particles such as styrene resin particles, urea-pormarine condensate resin particles, aluminum hydroxide, magnesium hydroxide, calcium carbonate, titanium, talc, kaolin, silica, alumina, etc.Other auxiliary ingredients include: For suppression, zinc chloride, zinc sulfate, sodium citrate, guanidine sulfate, carunium gluconate, sorbitol, sucrose, etc. are used.

In order to obtain the heat-sensitive recording material according to the present invention, the above-mentioned steps 13
- Prepare each layer-forming coating solution by dissolving or dispersing the layer-forming components in an appropriate solvent, apply each coating solution onto a support, and dry it to form a laminated structure including a diazo compound layer and a phloroglucin layer. products. 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, toluene, xylene, n-hexane, n-
Examples include nonpolar or polar organic solvents such as heptane, nclohexane, kerosene, methyl isobutyl ketone, methyl cellosolve, acetone, methyl ether ketone, dimethyl ether, and siloxane.

In the present invention, when the diazo compound layer and the phloroglucin layer are laminated in direct contact with each other, the solvent for forming the upper layer coating solution is appropriately selected in relation to the components contained in the lower layer in order to prevent color development due to the reaction between the two. It is necessary to.

That is, the solvent for forming the upper layer coating liquid must not dissolve the coupling reaction components contained in the formed lower layer.

For example, when a phloroglucin layer-forming coating solution is first applied and dried on the support, and then a diazo compound layer-forming coating solution is applied and dried to form an upper layer, the solvent in the diazo compound layer-forming coating solution is contained in the lower layer. It must be insoluble in phlorogluene. When phloroglucin in the lower layer is eluted into the coating solution during coating of the fabric solution during the formation of the diazo compound layer, a coloring reaction occurs during the coating process.

In the diazo compound layer and Floroglu 77 layer formed in the present invention, each of the reactive components may be present in the layer in the form of either discontinuous particles or continuous particles. In this case, "discontinuous particles" refers to particles obtained when layer formation is performed using a dispersion in which a diazo compound or phloroglucin is dispersed as insoluble solid particles in a solvent. "Continuous particles" refers to the state of existence of reaction components in a layer, and "continuous particles" are obtained when layer formation is performed using a solution in which a diazo compound or phloroglucin 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 preservability, it is preferable that one of the diazo compound layer and the phloroglune layer be a discontinuous particle layer, and the other be a continuous particle layer. Yes. If both of them are discontinuous particle layers, thermal coloring properties tend to decrease, while if both of them are continuous particle layers, thermal coloring properties tend to become too large and storage stability tends to decrease.

In the present invention, the stacking order of the diazo compound layer and the phloroglucin layer on the support (for example, paper, synthetic paper, plastic film, etc.) is arbitrary;
The diazo compound layer and the phloroglucin layer can be laminated in that order or in the reverse order. Moreover, both layers do not necessarily have to be continuous, and an auxiliary component layer can be interposed between the two layers. Additionally, auxiliary component layers can be used as top and/or bottom layers. Next, examples of laminating various component layers used in the present invention on a support will be shown. In addition, each code shown below means the following.

D Diazo Compound C・Phloroglucin X・Thermofusible or Thermosetting Substance Brackets [ ] indicate that a layer is formed. An example of this is as follows.

[D] Diazo compound layer (Dx) Layer containing a diazo compound and a heat-melting or heat-softening substance CD+Y) Layer containing a diazo compound and a filler or other auxiliary component u+[0]/(Dxx) , (2) [D+X]/
[CD+3+cD'l/(c+x), (4)
[C1X]/[D]+5+[0+X)/[:D+X),
+6+(n+x)/Cc+x)+7+ (0+X
) / [D+X+Y], +81['D+X]/C0
fX 10Y')+9+(c+x+Y]/CD+x+y),
QtlCD10X10Y)/[0+X+Y'), oIl(0
)/Cy)/(n+x), a2(nxx)/(Y)/[
0) 17-os[D':l/[y]/[c+x), o41cc+X
]/[Y':l/CD'3O! l[C1X M[Y]
/CD-1-X'], as(c+x)/(y)/[I
−++x), θη[Y)/[0+Xl/CDI/[X+
Y':l, 01D[Y]/[0+l/CD+X')/[
X+Y), al[0+X]/CD+X]/[0':l/
(X+Y], ■[Y]/[C+X)/CD+X')/[
X]/(Y'll, 2+1[Y)/(0+X]/C
D+X']/CC+Y]/CY)c@[x10Y]
/[c+X]/[D+X] (to) CD+X)/CY
)/[0+X], a41[X+Y]/[C! )/
CD + can be applied, and
In the case of the present invention, characters and images recorded on the surface can be fixed by forming the image by heating and then decomposing the unreacted diazo compound by light.

Further, the heat-sensitive recording material of the present invention utilizes its fixing properties,
It can be applied to recording and creating necessary items for securities, gift certificates, admission tickets, certificates, slips, etc. Furthermore, the heat-sensitive recording material of the present invention can of course be applied as a heat-developable copying paper.

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

Example 1 [C-1] Liquid phloroglucin 3 parts by weight Sodium citrate 0.5tt Polyvinyl alcohol (10% aqueous solution) Io zz water
8
6,5//horn The above product was dissolved to prepare a (0-1) solution.

(0-2': 1 liquid phloroglucin 5 parts by weight stearamide 5 polystyrene resin (□5soo) 2//benzene
88/l The above composition was dispersed for 24 hours using a ball mill to prepare a dispersion liquid (liquid 0-21).

Tartaric acid 0.17/Stearic acid amide 10//Polyester resin (Wyo 1000) 2 tt Chlohexane 85.1 mm The above composition was dispersed for 24 hours using a ball mill to form a dispersion [D
−]] solution was prepared.

CD-21 liquid N-octadecylcarbamoylbenzene 15/
/Kaolin 'l //
Polyvinyl alcohol (10% water soluble 1) 20
//water
Dispersion liquid CD-2) was prepared by dispersing the above composition for 24 hours using a ball mill.

(y-]) Liquid silica 5 parts by weight Paraffin wax 3 parts by weight Polyvinyl alcohol (10% aqueous solution) 10 tt water
82
The above composition was dispersed for 1 hour using a homomixer to prepare a dispersion liquid [Y-+].

[Y-2] Liquid calcium carbonate 5 parts by weight Polyvinyl acetate emulsion (solid content 50%) 4 Water
9
1. Among the compositions described in section 2, calcium carbonate was dispersed in water using a homomixer for 1 hour, and then polyvinyl acetate emulsion was added and stirred to become uniform to obtain a dispersion [
Y-2] solution was prepared.

(D-10) For liquid comparison, [D-10
': l solution was prepared.

21- For comparison of [C-10] solution, prepare [0-10] solution j7 in the same manner as in [0-1] solution except that phloroglucin was replaced with the following.

2. Sodium 3-dihydroquinaphthalene-6-sulfonate Using the above-mentioned layers in the combinations shown in Table 1 below,
It is coated on the surface of high-quality paper (approximately 50 g/m2), dried, and laminated in layers with a coating weight of 2 to 3 g/m'' (solid content), and then calendered to a Bekk smoothness of 400 seconds. A diazo thermosensitive recording material was obtained.

Table 1 Comparative Example Using the azo thermosensitive record H obtained as described above as a sample, G-I was measured using Rifax 303 (manufactured by Ricoh).
After printing in f mode, it was completely exposed and fixed using a Ricopy Istart 4 model (manufactured by Ricoh). These materials did not develop color even when heated, and the images did not disappear even when exposed to extreme solvents.

Next, the diazo thermosensitive recording material obtained above was tested for color density and storage stability. Table 2 shows the results.
Shown below.

Note that the solid print density in the 1-I+ mode was measured using a Macbeth densitometer (old)-5+4 of the color density gauge Fax 303. In addition, the storage stability of the sample is 40iC1 humidity 9
A forced deterioration test was performed in which the sample was left in a dark place at 0% R, l-1 for 24 hours, and the skin density before and after the test was measured. In this case, the Macbeth density set was used for density measurement.

If the skin density value is 0.15 or less, it is confirmed that the heat-sensitive recording material has a shelf life of 3 years when stored in the dark at room temperature and humidity.

Rice Comparative Example Half-reached Color developed immediately after application From the above results, it can be confirmed that the product of the present invention clearly has improved storage stability and thermal response than the comparative example.

Example 2 [c-11': 7 parts by weight of 1-liquid fluoroglue 3 parts by weight of sodium citrate 0.511 polyvinyl alcohol (1 (1% aqueous solution) 10 parts of heavy FA water

86.5'/1-Dissolve the silk composition [0-11']
l was prepared.

C (Nie 12) Liquid Fluorodarun 5 Small part Stearic acid amide 5 Polystyrene resin (cup , Dispersion liquid [0-12] liquid was prepared from 1.

[I)-11] Liquid 4 Tartan acid 0.1//Stearic acid amide 1 Ort polyester resin (both MW 10i) 0) 2 tt
/ Kuro・＼gi → Noon 85. ! ]
7/ Using a ball mill to prepare the above composition1. Dispersion was carried out for 24 hours to prepare a dispersion liquid CI)-11).

CI) -12'll liquid-25= N-octade/lunoylhamoylbenzene 15
11 Kaolin 2 // Polyvinyl alcohol (10% aqueous solution) 20
//water
61 // The upper silk composition was dispersed for 24 hours using a ball mill to prepare a dispersion liquid (+)-12).

[:Y-I+]Liquid/Ritsuno
5-layer b1 SHOJU paraffin wax
3 tt polyvinyl alcohol (1
0% water solution at night) to water
82...The above composition was dispersed for 1 hour using a homomixer to prepare a dispersion liquid [Y-++].

Using the above mixture in the combination shown in Table 3, apply it to the surface of 1-paper (approximately 50 g/yy/'), dry it,
Laminate each layer with a total weight of 2 to 3 g/m'' (solid content), and further use a calender to achieve Beck smoothness of 400 seconds 26.
- A diazo thermosensitive recording material was obtained.

Table 3 Comparative Example Using the diazo heat-sensitive recording material obtained in 1 as described above as a sample, the Q
- After printing in I+ mode, recopy...Istart type 4 [
■Made by Ricoh] was fully exposed and fixed. These samples did not develop any color even after heating for 1 to 71 days, and the images did not disappear even after exposure to organic solvents.

Next, the heat-sensitive recording material obtained above was tested for color density and storage stability. As for the unity, the color density is d, the refax is 4 F+ 3 (the degree of solid printing in +-II mode is Macbeth IW j (old) -51・i)
It was measured with It's Dou, for storage use 10C of power sample.
A forced inferiority test was carried out in which the samples were left in a dark place at a humidity of 90%11.11 for 24 hours, and the ground pressure before and after the test was determined. In this case, the density measurement uses Macbeth density word 1 L/'r □If the skin density value is t+, 20 or less, it is always i'! ii. It is confirmed that it is a heat-sensitive recording material that has a shelf life of 2 years or more when stored in a dark place at normal humidity.

Table 4 Tsu Comparative Example 1 Color Development Immediately After Application From the above results, it can be seen that the product of the present invention is clearly satisfactory in storage 44 and thermal response. In the case of sample horse 7 obtained for comparison, the selection of the second layer coating liquid solvent was poor, and when the second layer coating liquid was applied, the coating liquid instantly developed color at 1-12. Unfortunately, it could not be used as recording material.

Patent applicant: Ricoh Representative Patent Attorney Toshiaki Ikeura 9- Procedural amendment (10,000 people) 1 Indication of the case 1981 Patent application No. 1 θ02θ da Katsura 2 Name of the invention Diazo thermosensitive recording material 3 Amendment Relationship with the patent applicant's name (674) Stock Corporation 71: Ricoh 4 agent address Tokyo Parts Ward 1-. Osaki 11 Nagi 22 No. 15 No. 5 Amendment Order Date 1 Voluntary

Claims (4)

[Claims] (1) At least one diazo compound selected from diazo compounds represented by the following general formula (r) and phloroglucin as a coupler thereof are laminated as separate layers on a support. Diazo thermosensitive recording material. General formula (1) (In the above formula, R1+ R2 and R3 are hydrogen, lower alkyl group, lower alkoxy group, or halogen; n is 0 or 1
an integer; X is an acid residue or an acid residue forming a double salt with a metal salt) (2) The method according to claim 1, wherein in the diazo compound represented by general formula (1), X is a water-insoluble salt-forming acid residue. (3) At least one diazo compound selected from the diazo compounds represented by the following general formula (1) and phloroglucin as a coupler thereof are laminated as separate layers on a support, and the diazo compound layer and/or a diazo-based heat-sensitive recording material, characterized in that the phloroglucin layer contains a thermofusible substance in an amount of 2 to 30 parts by weight per 1 part by weight of the diazo compound. General formula (1) (In the above formula, R1+ R2 and Ita are hydrogen, lower alkyl group, lower alkoxy group, or halogen; 0 is an integer of 0 or 1; X forms a double salt with an acid residue or a metal salt. (acid residues) (4) The method according to claim 3, wherein in the diazo compound represented by general formula (I), X is a water-insoluble salt-forming acid residue.