JPH0686146B2 - Recording material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Field of Use of the Invention> The present invention relates to a recording material, and more particularly to a heat-sensitive recording material having improved color developability.

<Prior Art> Thermal recording materials using an electron-donating colorless dye and an electron-accepting compound are disclosed in Japanese Examined Patent Publication Nos. 45-14039 and 43-4160. The minimum required performance of such a heat-sensitive recording material is (1) sufficient color density and color sensitivity, (2) fog (color phenomenon during storage before use).
However, (3) the fastness of the color-developing body after color development is sufficient, and the like, but at present, those which completely satisfy these are not obtained.

Especially with the recent increase in the speed of thermal recording systems, the above (1)
The research for

As a method, it may be considered that the melting point of the electron-accepting compound itself is set to 60 to 100 ° C. However, it is difficult to control the melting point of the phenolic compound which is the most widely used electron accepting compound at present, and the phenolic compound itself is expensive and is not practical.

As other methods, JP-B-49-17748 and JP-B-51-39567 may be used in combination with an organic acid and a phenolic compound as an electron accepting substance, or a polyvalent metal salt of a compound having an alcoholic hydroxyl group. It is described to be used. In addition, Japanese Patent Publication No. 51-29945 describes that a copolymer of hydroxyethyl cellulose and maleic anhydride is used.

Further, JP-B-51-27599 and JP-A-48-19231 describe adding waxes.

Further, JP-A-49-34842, JP-A-49-115554, JP-A-50-149353, JP-A-52-106746, JP-A-53-5636.
JP-A-53-11036, JP-A-53-48751, JP-A-56-72996 and the like. Or a nitrogen-containing organic compound or a heat-fusible substance such as 2,3-di-m-tolylbutane or 4,4′-dimethylbiphenyl, or a carvone such as dimethylisophthalate, diphenylphthalate or dimethylterephthalate. It is described that an acid ester is added as a sensitizer. British Patent Publication No. 2,074,335A describes addition of hindered phenols.

However, the heat-sensitive recording materials produced by using these methods are insufficient in terms of color density and color sensitivity.

<Object of the Invention> Therefore, an object of the present invention is to provide a heat-sensitive recording material which has sufficient color density and color sensitivity and satisfies other conditions to be satisfied.

<Structure of the Invention> The object of the present invention has been achieved by a heat-sensitive recording material containing an electron-donating colorless dye, an electron-accepting compound and an ether derivative represented by the following general formula (I).

In the above formula, m represents 1 or 2.

Among the above ether derivatives, those having a melting point of 70 ° C to 185 ° C are preferable, and those having a melting point of 80 ° C to 140 ° C are particularly preferable.

The heat-sensitive recording material containing the ether derivative according to the present invention has sufficient color density, color speed and color sensitivity, less deterioration of color sensitivity with time and fog, and sufficient fastness of color image after color development.

These ether derivatives according to the present invention include aryloxyalkyl halides, aryloxyalkanol tosylates, arylglycidyl ethers, ether precursors such as aryloxyalkanol acetates, and polyhydroxyaromatics such as catechol, pyrogallol, resorcin, phloroglucin, and the like. It is synthesized by reacting.

In the reaction, bases such as caustic soda and potassium carbonate,
The reaction can be accelerated using a solvent such as methyl ethyl ketone, DMF tetrahydrofuran, or toluene.

For example, phenoxypropyl tosylate can be easily synthesized by stirring in a polar solvent with polyhydroxyaromatics at 80 to 95 ° C. for 2 to 3 hours with carbonic acid as a catalyst.

Next, specific examples of the ether derivative according to the present invention will be shown, but the present invention is not limited thereto.

1.1,2-di-β-phenoxyethoxybenzene 2.1,2-di-β-phenoxyethoxybenzene 3.1,3,5-tri-β-phenoxyethoxybenzene 4.1,4-di-β-phenyl Enoxyethoxybenzene 5.1,2,3-tri-β-phenoxyethoxybenzene Specific synthesis examples are shown below.

Synthesis Example 1 Synthesis of 1,2-di-β-phenoxyethoxybenzene 0.1 mol of β-phenoxyethyl tosylate, catechol
0.05 mol and 0.06 mol of carbonate were weighed, 30 ml of DMF was added, and the mixture was heated to 80-95 ° C for 3 hours while stirring. Crystals precipitated when the reaction mixture was poured into ice water. Recrystallization from methanol gave 1,2-di-β-phenoxyethoxybenzene, melting point 120-121 ° C.

Synthetic Examples 2 to 4 Resorcinol, hydroquinone, and phloroglucinol were used instead of the catechol of Synthetic Example 1 to carry out a reaction to obtain the following ether derivative.

1,3-di-β-phenoxyethoxybenzene melting point 104-5 ° C 1,4-di-β-phenoxyethoxybenzene melting point 184-5 ° C 1,3,5-tri-β-phenoxyethoxybenzene melting point 109-110 ° C Examples of the electron-donating colorless dye used in the present invention include triarylmethane compounds, diphenylmethane compounds,
Xanthene compounds, thiazine compounds, spiropyran compounds, etc. are used. As an example of some of these, as triarylmethane compounds, 3,3-bis (p-dimethylaminophenyl) -6-dimethylaminophthalide (that is, crystal violet lettactone), 3,
3-bis (p-dimethylaminophenyl) phthalide, 3
-(P-Dimethylaminophenyl) -3- (1,3-dimethylindol-3-yl) phthalide, 3- (p-dimethylaminophenyl) -3- (2-methylindole-
3-yl) phthalide, etc., and examples of diphenylmethane compounds include 4,4′-bis-dimethylaminobenzhydrin benzyl ether, N-halophenyl-leukoauramine, N-2,4,5-trichlorophenyl. There are leuco auramine and the like, and as the xanthene-based compound, rhodamine-B-anilinolactam, rhodamine (p-nitroanilino) lactam, rhodamine B (p-chloroanilino) lactam, 2-dibenzylamino-6-diethylaminofluorane, 2-anilino-6-diethylaminofluorane, 2-anilino-3-methyl-6-diethylaminofluorane, 2-anilino-3-methyl-6-cyclohexylmethylaminofluorane, 2-o-chloroanilino-6-diethylaminofluor Oran, 2-m-chloroanilino-6-die Le aminofluoran, 2- (3,
4-dichloroanilino) -6-diethylaminofluorane, 2-octylamino-6-diethylaminofluorane, 2-dihexylamino-6-diethylaminofluorane, 2-m-trifluoromethylanilino-6-diethylaminofluorane , 2-butylamino-3-chloro-
6-diethylaminofluorane, 2-ethoxyethylamino-3-chloro-6-diethylaminofluorane, 2
-P-chloroanilino-3-methyl-6-dibutylaminofluorane, 2-anilino-3-methyl-6-dioctylaminofluorane, 2-anilino-3-chloro-6
-Diethylaminofluorane, 2-diphenylamino-
6-diethylaminofluorane, 2-anilino-3-methyl-6-diphenylaminofluorane, 2-phenyl-6-diethylaminofluorane, 2-anilino-3-
Methyl-6-N-ethyl-N-isoamylaminofluorane, 2-anilino-3-methyl-5-chloro-6-diethylaminofluorane, 2-anilino-3-methyl-
6-diethylamino-7-methylfluorane, 2-anilino-3-methoxy-6-dibutylaminofluorane,
2-o-chloroanilino-6-dibutylaminofluorane, 2-p-chloroanilino-3-ethoxy-6-N-
Ethyl-N-isoamylaminofluorane, 2-o-chloroanilino-6-p-butylanilinofluorane, 2
-Anilino-3-pentadecyl-6-diethylaminofluorane, 2-anilino-3-ethyl-6-dibutylaminofluorane, 2-anilino-3-ethyl-6-N-
Ethyl-N-isoamylaminofluorane, 2-anilino-3-methyl-6-N-ethyl-N-γ-methoxypropylaminofluorane, 2-anilino-3-chloro-
There are 6-N-ethyl-N-isoamylaminofluorane and the like, and as thiazine compounds, benzoyl leuco methylene blue-, p-nitrobenzyl leuco methylene blue-
Etc., and spiro compounds include 3-methyl-spiro-dinaphthopyran, 3-ethyl-spiro-dinaphthopyran, 3,3'-dichloro-spiro-dinaphthopyran, 3
-Benzylspiro-dinaphthopyran, 3-methyl-naphtho- (3-methoxy-benzo) spiropyran, 3-propyl-spiro-dibenzopyran and the like. These may be used alone or as a mixture. In particular, it is desirable to use two or more kinds of black color developing agents in combination.

Examples of electron-accepting compounds are phenol compounds,
Organic acid or its metal salt, oxybenzoic acid ester,
In particular, the phenol compound is preferably used because the amount thereof is small. For example, 2- (4-hydroxyphenyl) -2- (3-isopropyl 4-hydroxyphenyl) propane, 2- (4-hydroxyphenyl) 2- (3-allyl-4-hydroxyphenyl) propane, 2 -(4-hydroxyphenyl) -2- (3-methyl-4-hydroxyphenyl) propane, α-isopropyl-β-naphthol, methyl-4-hydroxybenzoate, monomethyl 4,9 dihydroxybiphenyl,
2,2-bis (4-hydroxyphenyl) propane, 4,4 '
-Isopropylidene bis (2-methylphenol), 1,
1-bis- (3-chloro-4-hydroxyphenyl) cyclohexane, 1,1-bis- (3-chloro-4-hydroxyphenyl) -2-ethylbutane, 4,4'-secondary isobutylidene diphenol, 4-hydroxybenzoic acid benzyl ester, 4-hydroxybenzoic acid-m-
Chlorobenzyl ester, 4-hydroxybenzoic acid β-
Phenyl ester, 4-hydroxy-2 ', 4'-dimethyldiphenyl sulfone, 1-t-butyl-4-p-hydroxyphenylsulfonyloxybenzene, 4-N-
Benzylsulfamoylphenol, 2,4-dihydroxybenzoic acid-p-methylbenzyl ester, 2,4-dihydroxybenzoic acid-β-phenoxyethyl ester, 2,
Examples thereof include 4-dihydroxy-6-methylbenzoic acid benzyl ester, zinc rhodanide and the like.

The ether derivative used in the present invention is used by being dispersed in a dispersion medium to a particle size of 5 μm or less by a pulverizer or a disperser. Alternatively, the electron-donating colorless dye and / or the electron-accepting compound may be added and dispersed at the same time when they are dispersed in a dispersion medium by a ball mill or the like.

The electron-donating colorless dye and the electron-accepting compound used in the present invention are pulverized and dispersed in a dispersion medium to a particle size of 5 μm or less, preferably 3 μm or less. Generally, 1 is used as the dispersion medium.
A water-soluble polymer aqueous solution having a concentration of about 10 to 10% is used, and dispersion is performed using a ball mill, a sand mill, an attritor, a colloid mill, or the like.

The ratio of the electron-donating colorless dye and the electron-accepting compound used is preferably between 1:10 and 1: 1 by weight, and further 1: 5.
Especially preferred is between 3 and 2: 3. The ether derivative is
It is added in a weight ratio of 20% to 300% with respect to the electron-accepting compound, and particularly preferably 40% to 150%.

If the addition amount of this ether derivative is less than 20%, the effect of improving the sensitivity which is the object of the present invention is not sufficient,
With the above addition, the sensitivity is lowered.

Additives are further added to the coating liquid thus obtained in order to meet various requirements.

As an example of the additive, an oil-absorbing substance such as an inorganic pigment is dispersed in order to prevent the recording head from being soiled at the time of recording.Furthermore, fatty acids and metallic stones are added in order to enhance the releasability of the head. Ken and the like are added. Therefore, generally, in addition to a color former and a color developer that directly contribute to color development, a pigment wax, an additive and the like are coated on a support to form a heat-sensitive recording material.

Specifically, as the pigment, kaolin, calcined kaolin, talc, wax, diatomaceous earth, calcium carbonate, aluminum hydroxide, zinc oxide, magnesium oxide, magnesium carbonate, titanium oxide, barium carbonate, gypsum, urea-formalin filler, It is selected from cellulose fillers and the like.
Examples of waxes include paraffin wax, carnaw wax, microcrystalline wax, polyethylene wax, and higher fatty acid esters.

Examples of the metal soap include fatty acid metal salts, that is, zinc stearate, aluminum stearate, calcium stearate, zinc oleate and the like.

These are dispersed and applied in a binder. Water-soluble binder is generally used, polyvinyl alcohol, hydroxyethyl cellulose, hydroxypropyl cellulose, ethylene-maleic anhydride copolymer, styrene-maleic anhydride copolymer, isobutylene-maleic anhydride copolymer, Examples thereof include polyacrylic acid-acrylamide copolymer, polyacrylic acid amide, starch derivative, casein, gelatin and the like. Further, a water-proofing agent (gelling agent, cross-linking agent) is added for the purpose of imparting water resistance to these binders, or emulsion of hydrophobic polymer, specifically, styrene-butadiene rubber latex, acrylic resin emulsion, etc. It can also be added.

The coating solution is generally applied on a smooth base paper, preferably a neutral paper, and calendered.

Generally, the coating amount is ² to 10 g / m ² as a solid content, the lower limit is determined by the concentration at the time of color development by heating, and the upper limit is determined mainly by economic constraints.

<Examples of the Invention> Examples will be shown below, but the present invention is not limited to these examples.

Example (1) Preparation of Samples 1 to 2 2-anilino-3-chloro- which is an electron-donating colorless dye
0.5 g of 6-diethylaminofluorane and 2-anilino-3
-Methyl-6-N-methyl-N-isoamylaminofluorane 3.5 g and 3% polyvinyl alcohol (saponification number 99
%, Polymerization degree 1000) and 35 g of an aqueous solution were dispersed in a sand mill.

On the other hand, bisphenol A1 which is also an electron-accepting compound
0 g is dispersed with 100 g of a 2% polyvinyl alcohol aqueous solution in a sand mill. Further, 12 g of the ether derivative shown in Table 1 was dispersed with a 2% aqueous solution of polyvinyl alcohol in a sand mill, and after mixing these 4 types of dispersions, 20 g of kaolin (diiodia kaolin) was added and well dispersed, and then paraffin was added. A coating liquid was prepared by adding 5 g of 50% dispersion of Watsuku emulsion (Chukyo Yushi Fat Cerosol # 428).

The coating solution was applied onto neutral paper having a basis weight of 50 g / m ^{2 so} that the solid content was 5.0 g / m ² , dried at 60 ° C for 1 minute, and then super-calendered at a linear pressure of 68 kgW / cm. A coated paper was obtained by applying.

The coated paper is heated at 300 mJ / mm ² by Facsimile.
The color density was determined by heating with.

The results are shown in Table 1.

(2) Preparation of Comparative Samples With the same prescription as that used for preparation of Samples 1 to 3,
A similar test was performed using stearic acid amide instead of the ether derivative.

The results are also shown in the table.

From Table 1 it can be seen that the recording material according to the invention is clearly more sensitive.

Claims (1)

[Claims] 1. An electron-donating colorless dye, an electron-accepting compound,
And a recording material containing an ether derivative represented by the following general formula (I). In the above formula, m represents 1 or 2.