JPS6141595A - Thermal recording body - Google Patents

Abstract

PURPOSE:To obtain excellent storage stability over a long period of time without generating precoupling, by using a salt formed of a specific guanidine derivative and a hydroxynaphthoic acid derivative. CONSTITUTION:A thermal recording layer containing a diazonium compound and at least one or more of a salt formed of a guanidine derivative represented by formula I and a hydroxynaphthoic acid derivative represented by formula II is provided to a support. In formulae I, II, R1, R2, R3, R4, R5 and R6 are an aryl group which may be substituted with an alkyl group, an alkoxyl group, a nitro group or a halogen atom; an aralkyl group which may be substituted with an alkyl group, an alkoxyl group, a nitro group or a halogen atom; an alkyl group; a cycloalkyl group or a hydrogen atom. The salt of these derivatives is formed by adding both derivatives in a solvent dissolving at least one of said derivatives, for example, alcohol in an almost equimolar ratio and refluxing the resulting solution for several hr.

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 develop a color when it comes into contact with the dye, and brings a blue coloring 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, even after applying heat and recording, if the heat source is brought too close by mistake, the entire heat rising part will develop color, making the necessary recording unreadable. have. Therefore, it has been difficult to apply it to important records that require preservation.

Therefore, in recent years, development of a diazo-based heat-sensitive recording material that utilizes a color-forming reaction between a diazo compound and a coupler has been progressing as a heat-sensitive recording material that can be fixed.

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., which are generally used as coloring aids, decompose little by little even at room temperature, so precoupling occurs during storage and the recording layer becomes colored. Defects may 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 salts formed from certain guanidine derivatives and hydroxynaphthoic acid derivatives.

"Means for Solving the Problems" The present invention supports a heat-sensitive recording layer containing at least a diazonium compound and one or more salts produced from a guanidine derivative and an acid derivative represented by the following general formula CI). This is a heat-sensitive recording medium characterized by being attached to the body.

[In the formula, R1, R2, R3, R, R, and R6 are each an alkyl group, an alkoxyl group, a nitro group, or an aryl group optionally substituted with a halogen atom; an alkyl group, an alkoxyl group, a nitro group, or a halogen Indicates an aralkyl group which may be substituted with an atom; an alkyl group; a cyclic alkyl group or a hydrogen atom. [Function] Specific examples of the salt produced from the above-mentioned specific guanidine derivative and hydroxynaphthoic acid derivative used in the present invention include the following compounds, but are of course limited to these. , p. 23
2°C) Note that the salt produced from the above-mentioned specific guanidine derivative and hydroxynaphthoic acid derivative used in the present invention is generally prepared using a suitable solvent that dissolves at least one of the guanidine derivative and the hydroxynaphthoic acid derivative,
For example, it is produced by adding equimolar amounts of both to alcohol and refluxing for several hours. In addition, two or more of these salts may be used in combination, and since the blending ratio varies depending on the type of salt used, it is generally not specified, but is generally 0.1 to 1 part by weight of the diazo compound. 30
It is desirable to use 1 to 10 parts by weight, more preferably 1 to 10 parts by weight.

Traditionally, guanidine derivatives have been used as coloring aids,
Although it is known that hydroxynaphthoic acid derivatives are used as couplers, the desired effects of the present invention cannot be obtained simply by using them together; This can be obtained for the first time by using .

Various materials are known as the diazo compound used in combination with the salt produced from the specific guanidine derivative and hydroxynaphthoic acid derivative, 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-hydroxyethylanilinediazonium, 4-benzamide -2,5-jethoxybenzenediazonium, 2-N,N-diethyl-m-
) luidine diazonium, a double salt of a chloride such as 6-morpholino-m=toluidine diazonium and zinc chloride, and tetraphenylene.

In the heat-sensitive recording material of the present invention, since a salt produced from the above-mentioned specific guanidine derivative and hydroxynaphthoic acid derivative is used, a diazo compound coupler is not necessarily required, but the diazo compound and the above-mentioned specific salt type etc. Of course, it is also possible to use various conventionally known couplers in combination, depending on the situation.

Specific examples of such couplers include resorcinol, gongtecol, phloroglucin, α-naphthol, 1.5-
Di-hydroxynaphthalene, 2,5-dimethyl-4-morpholinomethylphenol, sodium 1-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, 1-hydroxy-2-naphthoic acid-0-methoxybenzamide, 2-hydroxy-3-
naphthoic acid benzamide, 2-hydroxy-3-naphthoic acid-m-nitrobenzamide, 2-hydroxy-3-
Examples include naphthoic acid-p-chlorobenzamide, 2-hydroxy-3-naphthoic acid-〇-ethoxybenzamide, and 2-hydroxy-3-naphthoic acid-2,5-dimethoxybenzamide, which can be used to create images of any color tone. In order to obtain the following, one type or a mixture of two or more types can be used.

The proportion of such couplers to be used in combination is appropriately selected depending on the materials used, but it is generally appropriate to use them in an amount of 0.1 to 10 parts by weight 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 and at least one salt formed from a specific guanidine derivative and a hydroxynaphthoic acid derivative as described above is used as a support. However, such a heat-sensitive recording layer is generally formed by preparing a coating solution containing the above-mentioned substances and coating it on a support.

In addition, 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 esters of naphthoic acid, and diphenyl carbonate derivatives are blended as appropriate. .

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, by using a suitable coating device such as an air knife coater, roll coater, blade coater, etc., dry weight is 3 to 10 g/n. The coating is dried to a certain extent.

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.

Parts by weight and weight % are shown respectively.

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

Preparation of B solution 1.3-diphenylguanidine and 2-hydroxy-3-
Naphthoic acid-0-ethoxybezamide salt
10 parts 20% aqueous dispersion of stearic acid amide 40 parts 10% aqueous solution of polyvinyl alcohol 5
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 49g/I high-quality paper using a wire bar so that the dry weight was 4g/I, and then dispersion A was similarly applied on top of the coated liquid layer at a dry weight of 4g/I. 4 g/
The coating was coated and dried to obtain a heat-sensitive recording material.

Example 2 Preparation of Solution A 4-morpholino-2,5-dibutoxybenzenediazonium hebutaffluoride phosphorus 2-part titanium oxide
50 parts polyvinyl alcohol 10% water 18 Wi 50 iJ water
100 parts of the above composition was dispersed in a ball mill for 48 hours to prepare Solution A.

Solution B Salt of 1,3-di-o-1-lylguanidine and 2-hydroxy-3-naphthoic acid benzamide manufactured by 1jil
25 parts 1-hydroxy-2-naphthoic acid benzamide 10 parts 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 Preparation of Solution A 4-(4-methoxy)-benzoylamino-2,5-jethoxybenzenediazonium tetraborofluoride
2 parts fine powder silica
25 parts barium sulfate 25
1 part citric acid 2 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 1. Salt of 3-di-o-)ruylguanidine and 2-hydroxy-3-naphthoic acid-〇-ethoxybenzamide
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 A-wave preparation p-N,N-diethylaminobenzenediazonium tetraborofluoride 2 parts thiourea 2 parts tartaric acid
10% toluene solution of 2 parts vinyl chloride/vinyl acetate copolymer
50 parts Fine powder silica 25 parts Toluene 50 parts The above composition was dispersed in a ball mill for 48 hours to prepare Solution A.

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

The above dispersion A was coated and dried on a 49 g/y high-quality paper using a wire bar to a dry weight of 3 g/rd, and dispersion B was similarly applied on top of the coated layer. is 4
The coating was coated and dried to obtain a heat-sensitive recording material of g/rrr.

Comparative Example I A-wave preparation p-N,N-diethylaminobenzenediazonium tetraphenylboron 2 parts 1.3-
Diphenylguanidine 5 parts Calcium carbonate
50 parts polyvinyl alcohol 1 part
0% aqueous solution 50 parts water
48 parts of the above composition in a ball mill
After time dispersion, ・Liquid A was prepared.

B? & Preparation 2-hydroxy-3-naphthoic acid-〇=ethoxybenzamide 10 parts 20% aqueous solution of stearic acid amide 40 parts 10% polyvinyl alcohol
Aqueous Solution 509p 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.

Comparative Example 2 The 1,3-diphenylguanidine of Solution A of Comparative Example 1 was mixed with 1.
A thermosensitive recording material was obtained in the same manner as in Comparative Example 1 except that 3-di0-)ruylguanidine was used.

Comparative tests were conducted on the color density and storage 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, after which the color density was measured using a Macbeth density needle (yellow filter). Regarding storage stability, the capri density of the heat-sensitive recording material immediately after coating and after being left at 40°C and 90% RH for one day was measured using a Macbeth density needle (yellow filter). I compared it. The results of each test are shown in Table 1.

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

The heat-sensitive recording material of the present invention has excellent storage stability over a long period of time without causing pre-coupling and coloring of the recording layer during storage as in conventional recording materials. . Such an effect cannot be obtained simply by using a guanidine derivative and a hydroxynaphthoic acid derivative in combination, but is a unique effect that can only be obtained by incorporating them in the form of a specific salt in the recording layer as described above.

Claims (1)

[Claims] At least a diazonium compound and the following general formula [I
] A heat-sensitive recording layer comprising, on a support, a heat-sensitive recording layer containing one or more salts produced from a guanidine derivative represented by the following general formula [II] and a hydroxynaphthoic acid derivative represented by the following general formula [II]. . ▲There are mathematical formulas, chemical formulas, tables, etc.▼[I] ▲There are mathematical formulas, chemical formulas, tables, etc.▼[II] [In the formula, R_1, R_2, R_3, R_4, R_5, and R_6 are alkyl groups, alkoxyl groups, and nitro groups, respectively. An aryl group that may be substituted with a group or a halogen atom; an alkyl group, an alkoxyl group, a nitro group, or an aralkyl group that may be substituted with a halogen atom; an alkyl group; a cyclic alkyl group or a hydrogen atom. ]