JPH01301366A - Thermal recording material - Google Patents

Abstract

PURPOSE:To obtain a thermal recording material capable of obtaining high printing density by low energy, by a method wherein a compound having zeolitic water is contained in a thermal recording layer. CONSTITUTION:For a thermal recording material, a thermal recording layer which colors by heat is established on a base material, and a compound containing zeolitic water is contained in the thermal recording layer. When printed, water kept as zeolitic water is released. By dispersing the released zeolitic water uniformly in the thermal recording layer, coloring of high density can be obtained by low energy. As a compound containing zeolitic water, synthetic or natural zeolitic mineral is mentioned. As an analcime group, there are analcite, pollucite, picite, etc. When the thermal recording material forms a visible image by answering heat, any one thereof may be used. The thermal recording material is applied on the base material, is dried, and is processed by treatment with a calender or the like to be applied to service. The calender treatment improves close adhesion to a thermal head in printing and increases printing efficiency.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of the Invention) The present invention relates to a heat-sensitive recording material, and more particularly to a heat-sensitive recording material capable of obtaining a high-density recorded image with a small amount of thermal energy.

(Prior Art) Regarding thermal recording, many methods have been known for a long time. For example, heat-sensitive recording materials using an electron-donating dye precursor and an electron-accepting compound are disclosed in Japanese Patent Publications No. 4160/1983, Japanese Patent Publication No. 14039/1987, and the like. In addition, heat-sensitive recording materials using diazo compounds were published in Japanese Patent Application Laid-open No. 59-
No. 190886, No. 63-98485, etc., and a heat-sensitive recording material using a chelate compound formed from ferric stearate and gallic acid is disclosed in U.S. Pat. No. 2.663.
．． No. 854, etc. In recent years, these thermal recording systems have been applied to a wide variety of fields such as facsimiles, printers, and labels, and their needs are expanding.

As needs expand, there is a growing demand for thermal recording to be performed faster and with lower energy. As one such means, it has been proposed in Japanese Patent Application Laid-Open No. 63-95981 that the sensitivity can be improved by eluting a liquid into the heat-sensitive recording layer during printing. According to the invention, by applying liquid to the heat-sensitive recording layer during printing, the adhesion between the thermal head and the heat-sensitive recording layer is improved, and the heat utilization efficiency is further improved, so even a small amount of printing energy is sufficient. J
degree is obtained.

However, there are many technical difficulties in efficiently eluting liquid during printing, and there are still many problems to be solved in order to achieve the desired effect.

(Object of the Invention) The object of the present invention is to obtain a heat-sensitive recording material that can provide high printing J degree with low energy.

(Structure of the Invention) As a result of intensive research to solve the above problems, the present inventors have found that in a heat-sensitive recording material in which a heat-sensitive recording layer that changes color by heat is provided on a support, It has been found that this can be achieved by including a compound containing Butsusanhydro.

According to the present invention, it has been discovered that during printing, water that is retained as water is released and uniformly diffuses into the heat-sensitive recording layer, resulting in color development with a high degree of J at low energy. be.

As a compound containing Butsu Sansui,
739. Special Publication No. 51-40468. Japanese Patent Publication No. 52-129
It is described in detail in Publication No. 442 and the like. Specifically, synthetic or natural zeolite minerals are mentioned, and the borofluorite group includes analsite, volcite, becide, etc., the borofluorite group includes hydrosodalite, molecular sieve, etc., and the borofluorite group includes sodalite, etc. , mesofluorite, Thomsonite, mountainite, etc.; Examples include 1 morden fluorite and dachial fluorite.

The heat-sensitive recording material used in the present invention may be any known material that forms a visible image in response to heat. Commonly known methods utilize the color reaction between an electron-donating dye precursor and an electron-accepting compound;
No. 14039, JP 60-23922, JP 57
-179836, 60-123556, 60-
No. 123557, No. 63-95977, etc., and those using diazo compounds, disclosed in JP-A No. 5
No. 9-190886, No. 60-6493, No. 81-2
No. 79593, No. 63-89378, etc., and a method using a chelate compound formed from ferric stearate and gallic acid, and is disclosed in U.S. Patent No. 2,66.
No. 3,654 and the like.

When utilizing a color reaction between an electron-donating dye precursor and an electron-accepting compound, examples of the electron-donating dye precursor that can be used include triphenylmethane phthalide compounds,
Diphenylmethane compounds, triphenylmethane compounds, fluoran compounds, triarylmethane compounds, indolylphthalide compounds, leucoauramine compounds, xanthine compounds, fetch 7 zine compounds,
Examples include spiropyran compounds. As the electron-accepting compound, phenol derivatives, phenol acetate, acid clay, salicylic acid derivatives, polyvalent metal salts thereof, etc. are preferable. Specifically, U.S. Patent No. 3.624. 107
No., JP-A-55-227253, JP-A-63-959
It is described in No. 77, etc.

Further, a thermofusible substance can be contained in the thermosensitive coloring layer in order to improve its thermal responsiveness. Examples of preferred thermofusible materials include benzyl p-benzyloxybenzoate, β-naphthyl-benzyl ether, stearamide, stearyl, urea, p-benzylbiphenyl, di(2-methylphenoxy)ethane, di( 2-methoxyphenoxy)ethane, β-naphthol-(p-methylbenzyl)ether, α-naphthylbenzyl-thyl, 1.4
-butanediol-p-methylphenyl ether, 1,
4-Butanediol-p-isopropylphenyl ether, 1,4-butanediol-p-tert-octylphenyl ether, 1-phenoxy-2-(4-ethylphenoxy)ethane, 1-phenoxy-2-(4-chloro phenoxy) ethane, 1,4-butanediol phenyl ether, diethylene glycol-bis(4-methoxyphenyl) ether, and the like. The thermofusible substances may be used alone or in combination, and in order to obtain sufficient thermal responsiveness, the thermofusible substances should be used in an amount of 10 to 3
It is preferable to use 00% by weight, more preferably 20 to 200% by weight.

In the case of a heat-sensitive recording material using a diazo compound, the diazo compound used has the general formula ArN2''X- (wherein Ar represents a substituted or unsubstituted aromatic ring, N2+ represents a diazonium group, and X- represents an acid 7 ions.
It can be arbitrarily selected from among the known birch compounds described in No. 6493, JP-A No. 61-27953, and the like.

Couplers that can be used as partners for color reaction with diazonium salts are diazo compounds (diazonium salts).
For example, compounds such as 2-hydroxy-3-naphthoic acid 7nylide are common, but a more detailed example is given in JP-A No. 5
It is described in 9-190886 and the like. In this case, it is preferable to add a basic substance to the recording layer of the heat-sensitive recording material, if necessary, for the purpose of making the system basic and promoting the coupling reaction. Specific examples include guanidines such as triphenylguanidine. More detailed examples can be found in JP-A-59-190886 and JP-A-61-2.
It is disclosed in Publication No. 7953 and the like. The amount of coupling component to be used is 0.1 to 1 part by weight of the diazo compound.
It is preferable to use 30 parts by weight and the basic substance in a proportion of 0.1 to 30 parts by weight. Moreover, the diazo compound is 0.
It is preferable to apply a coating of 05 to 5.09/po.

In the case of a heat-sensitive recording material using a diazo compound, a hydroxy compound, a carbamate ester compound, an aromatic alkoxy compound, or an organic sulfonamide compound can be added as a sensitizer to improve thermal color development. A detailed example is disclosed in Japanese Patent Application Laid-Open No. 62-77981. The amount used is 0.01 to 10 parts by weight, preferably 0.1 to 5 parts by weight, per 1 part by weight of the coupling component.
The parts by weight can be adjusted depending on the desired color density.

It is recommended to use at least one of the diazo compound, coupler, and basic substance used as necessary as the core material of the microcapsule from the viewpoint of preservation of recorded images and preservation of heat-sensitive recording materials. preferable.

Specific examples of this microcapsule include U.S. Patent No. 3.726.804, U.S. Pat.
It is described in JP-A-59-190886, JP-A-63-89378, etc. Other components not contained in the core material of the microcapsules are used in the heat-sensitive layer outside the microcapsules.

When a diazo compound is used as a coloring agent, the diazo compound can be decomposed by light irradiation after thermal printing and photofixing can be performed. In this case, it is preferable to use a hindered phenol compound and/or a derivative thereof in order to improve the fastness of the printed image after photofixing and to prevent discoloration of unprinted areas that are likely to be colored. Moreover, it can also be used in combination with other known anti-fading agents.

In addition, in the case of heat-sensitive recording materials using chelate compounds,
Examples of metal salts for forming chelate compounds include salts of zinc, lead, tin, iron, nickel, cobalt, copper, silver, etc., such as stearic acid, behenic acid, pelargonic acid, and cabroic acid. As reagents, tannin, gallic acid, hexamethylenetetramine, pyrogallol, hydroquinone, spiroindanthiosulfate, phenethidine chloride, dioxamides, etc. are used. It is described in p58 (published by Shashin Kogyo Publishing) etc.

These heat-sensitive recording materials are coated onto a support, dried, and subjected to a treatment such as a calender before use. The purpose of calendering is to improve contact with the thermal head during printing and increase printing efficiency.

Further, a protective layer may be provided on the heat-sensitive recording layer, if necessary. As the protective layer, any one known as a protective layer for heat-sensitive recording materials can be used. Furthermore, a back coat layer may be provided on the opposite side of the support from the heat-sensitive recording layer.

The purpose of this is to adjust the curl of the thermosensitive recording paper, to suppress the influence from the back side when a protective layer is provided on the recording layer, and to prevent static electricity. Further, an intermediate layer may be provided between the heat-sensitive recording layer and the support. By providing an intermediate layer, smoothness can be improved and printing sensitivity can be increased, especially when paper is used as a support. As the material for the intermediate tone layer, inorganic or organic pigments, hollow particles, etc. are used together with a binder.

The five-fluorine-containing compound of the present invention can be added to any of the above-mentioned heat-sensitive recording layers, including the protective layer and intermediate layer (undercoat layer).

The amount added is 0.5 to 10.09/nj, preferably 1 as the solid weight of the hydrofluorite water-containing compound.
．． It is 0 to 5.09/-.

As the support of the present invention, any support such as paper or synthetic resin film used in the field of ordinary heat-sensitive recording materials may be used.
Either can be used.

Specific examples include JP-A-81-2971760 and JP-A-62.
-53879, Japanese Unexamined Patent Publication No. 62-73991, etc.

EXAMPLES The present invention will be specifically explained below with reference to Examples, but the present invention is not limited to the following Examples.

(Example, 1) As an electron-donating dye precursor, 2-7nilino3-methyl-6-Nethyl-Niso7mil7minofluorane, as an electron-accepting compound, benzyl parahydroxybenzoate, thermofusible As a substance, β-naphthyl-benzyl ether, each 209, was dispersed with a 5% polyvinyl alcohol (Kuraray PVA-105) aqueous solution of 1009 in a ball mill for a day and night, and the average particle size was reduced to 1.5 μmQ to obtain each dispersion. . Further, calcium carbonate 809 was dispersed with a 0.5% sodium hexametaphosphate solution 1609 using a homogenizer to obtain a pigment dispersion.

Next, these liquids were mixed with the following composition to obtain a heat-sensitive coloring layer coating liquid.

Thermosensitive coloring layer coating liquid composition: 2-7 Nilino 3-methyl-8-N-ethyl-N1 isoamylaminofluorane dispersion 5 parts 2.2'-bis(4-human Oxyphenylon propane 1
Dispersion liquid 10 parts - 20% zinc stearate dispersion liquid 3 parts Furthermore, synthetic zeolite (Molecular Sieve type A dispersion liquid of a compound containing fluorite water was obtained. An additional 10 parts of this was added to the above heat-sensitive coloring layer coating solution, and coated on high-quality paper using a coating bar so that the dry weight of the coating layer was 7 g/bo, and dried at 50 ° C. for 1 minute. Further, it was processed at a pressure of 1 Kg/cm in a calender consisting of a combination of metal rolls and hard rubber rolls to obtain heat-sensitive recording paper.

(Example, 2) In Example 1, a compound dispersion containing fluorite water was coated and dried on high-quality paper in advance so that the solid content coating amount was Bq/r+f, and the heat-sensitive coloring layer coating liquid was applied as an upper layer on top of the solid content. Application amount is 5
After coating and drying, the coating was similarly calendered to obtain a heat-sensitive recording paper.

(Example 3) 3.45 parts of the following diazo compound and 18 parts of an adduct of xylylene diisocyanate and trimethylolpropane (3:l) were added and dissolved in a mixed solvent of 24 parts of tricresyl phosphate and 5 parts of ethyl acetate. This solution was mixed with 64 parts of an 8% polyvinyl alcohol aqueous solution and emulsified and dispersed at 20°C to obtain an emulsion having an average particle size of 2.5 μm.

Add 100 parts of water to the obtained emulsion, and add 60 parts of water while stirring.
After 2 hours, a capsule liquid containing a diazo compound in the core material was obtained.

Next, 10 parts of 2-hydroxy-3-naphthoic acid anilide, 10 parts of triphenylguanidine, and 20 parts of hydroquinone monobenzyl ether were added to 200 parts of 5% polyvinyl alcohol and dispersed in a ball mill for 24 hours to obtain an average particle size of 2 μm. A dispersion of the coupling component, triphenylguanidine and hydroquinone monohensyl ether was obtained.

Next, a coating liquid having the following composition was prepared and used as a coating liquid.

Coating liquid 140% i'A '6'i h By >'7
L"15" This coating solution was coated on the fluorite water-containing compound coated paper prepared in Example 2 so that the solid content weight was 69/rrr, and dried at 50°C for 1 minute to obtain heat-sensitive recording paper. .

(Example, 4-6) Example, replace the molecular sieve x type in 1.

Molecular sieve SK type, molecular sieve type A.

A thermosensitive recording paper was obtained in the same manner as in Example 1 except that chabasite was used.

(Comparative example, 1) Example 1. In this case, 32 parts of calcium carbonate dispersion was used without using synthetic zeolite. A thermosensitive recording paper was obtained in the same manner as in Example 1 except for the above.

(Comparative example, 2) In Example 2, substituted synthetic zeolite undercoat.

The procedure of Example 2 was followed except that calcium carbonate similarly dispersed in polyvinyl alcohol was used.

The thermal recording paper obtained in the manner described above was printed at a pulse intensity of 0.0000 using a thermal printing experimental device equipped with a Kyocera thermal head (LT-216-8MPDI) under conditions of a head voltage of 24 V and a pulse cycle of 101 IS. 8.1.0.1
Print at ゜2 and measure the print density using Macbeth reflection densitometer RD.
-9+ Measured at 8.

The results are shown in Table 1.

As shown in Table 1, the thermal recording paper according to the present invention exhibited good color density even at low energy.

Table, 1>

Claims (1)

[Claims] 1. A heat-sensitive recording material comprising a heat-sensitive recording layer disposed on a support that changes color by heat, characterized in that the heat-sensitive recording layer contains a compound containing fluorite water.