JPS61192588A - Thermal recording body - Google Patents

Abstract

PURPOSE:To obtain an optically fixable thermal recording body having good storage stability, by providing a thermal recording layer, wherein one kind of a specific heat-meltable basic compound is contained along with a diazonium compound and a coupler, to a support. CONSTITUTION:The thermal recording layer provided to a support contains one kind of a specific heat-meltable basic compound represented by formula along with a diazonium compound and a coupler. As the heat-meltable basic compound, 1,2,3-triphenylisourea, 1,3-diphenyl-2-(p-tolyl)-isourea or the like are used and two kinds of these heat-meltable basic compounds may be together used. Because the compounding ratio of this compound is different due to the kind of the compound to be used, said ratio is not determined unconditionally but 1-30pts.wt. of the compound is used per 1pt.wt. of the diazonium compound in general. In the above-mentioned formula, R1 and R2 are a lower alkyl group, a lower alkoxy group, a nitro group or a halogen atom substituted aryl group, R3 is an aryl group which may be substituted by a lower alkyl group, a lower alkoxy group, a nitro group or a halogen atom and X is an oxygen atom or a sulfur atom.

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to a heat-sensitive recording material, and particularly to a heat-sensitive recording material that can be fixed with light.

``Prior Art'' Conventionally, heat-sensitive technology utilizes the coloring reaction of a basic colorless dye and a coloring agent that can change color when it comes into contact with the dye, and brings a recoloring substance into contact with the dye to obtain a recorded image. Records are well known.

Since such a thermal recording medium has a structure in which a recorded image is obtained by heat, there is a defect that if the heat source is mistakenly brought close even after applying heat and recording, the entire heat source will develop color, making the necessary record unreadable. have. Therefore, it has been difficult to apply it to important records that require preservation.

Therefore, development of a diazo-based heat-sensitive recording material that utilizes a color-forming reaction between a diazo compound and a coupler is underway as a fixable heat-sensitive recording material.

Generally, in such a diazo-based heat-sensitive recording material, a diazo compound and a coupler are dispersed in the recording layer in the form of discontinuous particles, and a coloring aid that generates an alkali upon heating is used in combination to obtain a recorded image. It is composed of

However, inorganic or organic ammonium salts, alkali salts of trichloroacetic acid, urea, etc. used as color development aids decompose little by little even at room temperature, so pre-coupling occurs during storage and the recording layer becomes colored. Defects occur.

"Problems to be Solved by the Invention" An object of the present invention is to provide a diazo-based thermosensitive recording material that does not cause pre-coupling and has excellent storage stability over a long period of time. This is achieved by using a specific heat-melting basic compound as a color development aid.

"Means for Solving the Problems" The present invention provides a support with a heat-sensitive recording layer containing at least a diazonium compound and a coupler of a type of heat-melting basic compound represented by the following general formula CI). This is a heat-sensitive recording material characterized by:

R+ -N; CN H-Rz , R3
represents a lower alkyl group, an alkoxyl group, a nitro group, or an aryl group optionally substituted with a halogen atom; an alkyl group; an aralkyl group; a cyclic alkyl group, and X represents an oxygen atom; a sulfur atom. [Function] Specific examples of the specific heat-melting basic compound used in the present invention include the following compounds, but of course the compounds are not limited thereto.

1.2. '3-Triphenylisourea (m, p, 104°C) 1,3-diphenyl-2-(p-tolyl)-isourea
(m, p, 111°C) 1.3-
Diphenyl-2-(p-chlorophenyl)-isourea
(m, p, 155°C) 1,3-diphenyl-2-(α-naphthyl)-isourea
(m', p, 205°C) 1,3-diphenyl-2-(β-naphthyl)-isourea
(m, p, 201°C) L3-diphenyl-2-(
p-nitrophenyl)-isourea (
li, p, 196°C) 1.2.3-tricyclohexyl isourea (m, p, 104°C) 1.3-diphenyl-2-(p-tert-butyJL
/phenyl) ~ isourea (m', p, 159
°C) 1.2.3-) liphenylisothiourea (n+, p
, 82℃) 1.3-diphenyl-2-(p-nitrophenyl)-isothiourea (m, p'', 131℃) ■
-Phenyl-2-(p-nitrophenyl)-3-(p-
bromophenyl)-isothiourea (m, p', '15
8°C) 1.3-di-m-t-dyl-2-methylisothiourea
(m, p, 97.5
°C) 1.3-di-p-ayucyl-2-methylisothiourea (m, ρ, 84 °C)1.
3-bis(p-clophenyl)-2-methylisothiourea (m, 1.133°C) Two or more of these heat-melting basic compounds used in the present invention may be used in combination. Also, since the blending ratio varies depending on the type of compound used, it is not generally determined, but it is generally 1 to 30 parts by weight, more preferably 5 to 15 parts by weight, per 1 part by weight of the diazo compound. is desirable.

Various materials are known as diazo compounds that are used in combination with coloring aids made of such specific heat-melting basic compounds, such as p-N, N-dimethylaminobenzenediazonium, 4-morpholino-2 , 5-dibutoxybenzenediazonium, 4-(4-methoxy)-benzylamino-2,5-jethoxybenzenediazonium, 4
-morpholinobenzenediazonium, 4-pyrrolidino-
3=methylbenzenediazonium, p-N-ethyl-N
-Hydroxyethylaniline diazonium, 4-henzamido-2,5-jethoxybenzenediazonium, 4
- Morpholino-2,5-diisopropoxybenzenediazonium, 2-N,N-diethyl-m-)luidine diazonium, double salt of chloride and zinc chloride such as 6-morpholino-m-toluidine diazonium, tetraphenyl Examples include boron salts, boron tetrafluoride salts, phosphorous hexafluoride salts, and the like.

The coupler is not particularly limited, and various known materials can be used as long as it forms an azo dye by coupling with a diazonium salt in a basic atmosphere. Specifically, for example, reducinol, catechol, phloroglucin, α-naphthol, 1.5-
Di-hydroxynaphthalene, 2.5-dimethyl-4-morpholinomethylphenol, sodium l-hydroxynaphthalene-4-sulfonate, N-(3-morpholinopropyl)-3-hydroxy-2-naphthamide, 2-hydroxy-3 -(β-hydroxyethylamide carbonyl)naphthalene, 2-hydroxynaphthalene-3-carbonylgetanolamine, sodium 2-hydroxynaphthalene-3,6-disulfonate, acetanilide,
3-Methyl-5-pyrazolone, 1-phenyl-3-methyl-5-pyrazolone, 2-hydroxy-3-naphthoic acid-β-naphthylamide, 2-hydroxy-3-naphthoic acid-hydroxyethylamide, 1 -Hydroxy-2-
Naphthoic acid benzamide, 2-hydroxy-3-naphthoic acid benzamide, 2-hydroxy-3-naphthoic acid-
m-nitrobenzamide, 2-hydroxy-3-naphthoe62 p-chlorobenzamide, 2-hydroxy-
3-naphthoic acid-〇-ethoxyhenzamide, 2-hydroxy-3-naphthoic acid-2,5-dimethoxybenzamide, etc. are suitable, and by mixing one or more of these, images of any tone can be created. You can get it.

Note that the proportion of the diazonium salt and such coupler can be selected as appropriate depending on the materials used.
Generally, it is appropriate to use about 0.1 to 10 parts by weight of the coupler per 1 part by weight of the diazonium salt.

Thus, in the present invention, a heat-sensitive recording layer containing at least one of a diazonium compound, a coupler, and the above-mentioned specific heat-melting base compound is formed on a support. The heat-sensitive recording layer is formed by preparing a coating solution containing the above-mentioned substances and coating it on a support.

The coating liquid may contain preservability improvers such as sodium naphthalene sulfonate, sodium naphthalene disulfonate, sulfosalicylic acid, magnesium sulfate, and zinc chloride, and antioxidants such as thiourea, diphenylthiourea, and urea, as necessary. , acid stabilizers such as citric acid, malic acid, tartaric acid, phosphoric acid, saponin, starch, casein, gum arabic, polyvinyl alcohol, polyvinyl acetate emulsion, SBR
Various water-soluble and water-insoluble adhesives such as latex, pigments such as silica, clay, barium sulfate, titanium oxide, and calcium carbonate, as well as animal and vegetable waxes, petroleum waxes, and polyhydric alcohols of higher fatty acids. Melting point depressants such as esters, higher fatty acid amides, condensates of higher fatty acids and amines, synthetic paraffins, chlorinated paraffins, alkyl or aryl esters of naphthoic acid, and the like are appropriately blended.

The coating solution prepared in this way is coated on a suitable support such as paper, plastic film, synthetic paper, metal film, etc., but the coating method is not particularly limited and can be applied using a conventional method. For example, it is coated and dried using a suitable coating device such as an air knife coater, roll coater, blade coater, etc. at a dry weight of about 3 to 1 Og/tri.

The heat-sensitive recording material of the present invention thus obtained has excellent storage stability over a long period of time without causing pre-coupling and coloring of the recording layer during storage, unlike conventional recording materials.

In addition, in the recording medium of the present invention, a recorded image is formed using a thermal pen, a thermal head, etc. in the same way as a normal thermal recording medium, and then the entire surface is irradiated with ultraviolet light using a fluorescent lamp, a mercury lamp, etc., and the non-recorded portions are exposed. A recorded image can be fixed by decomposing unreacted diazonium salt.

"Example" The present invention will be described in more detail with reference to Examples below, but it is of course not limited to these.

Furthermore, unless otherwise specified, parts and percentages in the examples indicate parts by weight and percentages by weight, respectively.

Example I Preparation of Solution A p-N,N-diethylaminobenzenediazonium tetraphenylboron 2 parts calcium carbonate
50 parts 10% aqueous solution of polyvinyl alcohol 50 parts water
100 parts of the above composition was dispersed in a ball mill for 48 hours to prepare Solution A.

Preparation of Solution B 2-hydroxy-3-naphthoic acid-〇-ethoxybenzamide 25 parts 1,3-diphenyl-
2-(p-)lyl)-isourea
25 parts 20% aqueous dispersion of stearic acid amide 40
10% polyvinyl alcohol dissolved in water? &, 50
The above composition was dispersed in a ball mill for 48 hours to prepare Solution B.

The above dispersion B was coated and dried on 49 g/I high-quality paper using a wire bar so that the dry weight was 4 g/rd, and then dispersion A was similarly applied on top of the coated layer. The coating was coated and dried to obtain a heat-sensitive recording material of 4 g/rd.

Example 2 Preparation of liquid A 4-morpholino-2,5-dibutoxybenzenediazonium heptafluoride 2-part titanium oxide
50 parts 10% aqueous solution of polyvinyl alcohol 50 parts water
100 parts of the above composition was dispersed in a ball mill for 48 hours to prepare Solution A.

BWL preparation 2-hydroxy-3-naphthoic acid benzamide
25 parts 1,3-diphenyl-2-(
β-naphthyl)-isourea 25
Part: 20% aqueous dispersion of stearic acid amide: 40 parts: 10% aqueous solution of polyvinyl alcohol: 50 parts The above composition was dispersed in a ball mill for 48 hours to prepare Solution B.

A thermosensitive recording material was obtained in the same manner as in Example 1 except that the above dispersions A and B were used.

Example 3 A? & Preparation 4-(4-methoxy)-benzoylamino-2,5-
Diethoxybenzenediazonium boron tetrafluoride
2 parts fine powder silica
25 parts barium sulfate 2
5 parts citric acid 2 parts 10% aqueous solution of polyvinyl alcohol 50 parts water
1'00 parts of the above composition was dispersed in a ball mill for 48 hours to prepare Solution A.

Preparation of Solution B 2-hydroxynaphthalene-3-carbonylgetanolamine 25 parts 1,3-bis(p-chlorophenyl)-2-methylisothiourea
25 parts tribenzylamine 10 parts diphenylthiourea 2 parts 10% aqueous solution of polyvinyl alcohol 50 parts water
50 parts of the above composition was dispersed in a ball mill for 48 hours to prepare Solution B.

A thermosensitive recording material was obtained in the same manner as in Example 1 except that the above dispersions A and B were used.

Example 4 Solution A Preparation p-N,N-diethylaminobenzenediazonium boron tetrafluoride 2-part urea 2-part tartaric acid
2 parts 10% toluene solution of vinyl chloride/vinyl acetate copolymer 5
0 parts Finely powdered silica 25 parts Toluene 50 parts The above composition was dispersed in a ball mill for 48 hours to prepare Solution A.

B Lacquer preparation It was prepared in the same manner as Solution B in Example 1.

The above dispersion A was coated on 49 g/I high-quality paper using a wire bar so that the dry weight was 3 g/ld, and dried.
On top of the coating layer, dispersion B was applied in a dry weight of 4 g.
/ cd and dried to obtain a heat-sensitive recording material.

Comparative Example 1 1,3-diphenyl-2-(p-1-
A thermosensitive recording material was obtained in the same manner as in Example 1 except that stearylamine was used instead of (lyl)-isourea.

Comparative Example 2 A thermosensitive recording material was obtained in the same manner as in Example 2 except that 1,3-diphenyl-2-(β-naphthyl)-isourea in Solution B of Example 2 was changed to ammonium stearate.

Comparative tests were conducted on the color density, storage, and stability of the six types of heat-sensitive recording materials thus obtained.

That is, the recording medium was brought into contact with a hot plate at 110"C for 2 seconds to develop color, and the image was fixed by exposure to ultraviolet light, and then the color density was measured using a Macbeth densitometer (yellow filter). Regarding storage stability, the fog density of the heat-sensitive recording material immediately after coating and the heat-sensitive recording material after being left under conditions of 30'C and 70% RH for 7 days was measured using a Macbeth densitometer (yellow filter). The results of each test are shown in Table 1.

"Effect" As is clear from the results in Table 1, all the heat-sensitive recording materials obtained in the examples of the present invention have excellent storage stability.
Moreover, it exhibited good color density.

Table 1

Claims (1)

[Scope of Claims] A heat-sensitive recording material, characterized in that a heat-sensitive recording layer containing at least a diazonium compound and a coupler of one kind of heat-melting basic compound represented by the following general formula [I] is provided on a support. . ▲There are mathematical formulas, chemical formulas, tables, etc.▼ [I] [In the formula, R_1 and R_2 each represent a lower alkyl group, an alkoxyl group, a nitro group, or an aryl group that may be substituted with a halogen atom; a cyclic alkyl group, R_
3 represents a lower alkyl group, an alkoxyl group, a nitro group, or an aryl group optionally substituted with a halogen atom; an alkyl group; an aralkyl group; a cyclic alkyl group, and X represents an oxygen atom; a sulfur atom. ]