JPS58119892A - Heat-sensitive recording paper - Google Patents

Abstract

PURPOSE:To obtain a heat-sensitive recording paper having an improved color forming property and free of disappearance of recorded color images, by adding a plurality of fluoran compounds containing a specified fluoran compound as colorless electron-donating dyes. CONSTITUTION:In a heat-sensitive recording paper containing a substantially colorless electron-donating dye and an organic acid (preferably, a bisphenol) capable of coloring the dye upon contact with the dye, at least two kinds of fluoran compounds as said dye are contained and among them a fluoran compound of the formula[wherein R1 and R2 are each a (cyclo)alkyl, aralkyl or aryl, or R1 and R2 may be combined together to form a heterocyclic ring, except the case where both R1 and R2 are aryl, X is a halogen, and R3 is aryl or alkoxyalkyl](e.g., 3-diethylamino-6-chloro-7-anilinofluoran) accounts for 20-90wt%.

Description

[Detailed Description of the Invention] Regarding the Honyaku rr thermal recording paper, particularly improved coloring property,
And record #1 Concerning the 7tIIjC thermal recording paper that prevents the image from discoloring, it uses the physical and chemical changes in substances caused by thermal energy, using heat-sensitive paper, lamps, and heat energy, and is extremely useful. Many processes have been studied.

Recently, thermal writing paper has come to be used for facsimile output, computer output, and recording paper, taking advantage of its features such as primary color development and no need for the lA1# process. Ru. These are called A1 dye types, and Tokko Sho+J-l-/60,
It is disclosed in Japanese Patent Publication No. Sho-san J-/Sho-Jt, Japanese Patent Application Laid-open No. Sho 11-J7JjJ, etc.

When general IICQ thermal recording paper is used as recording paper, it has the advantage of being lightweight and compact, and has been rapidly used in recent years.

The essential performance that such thermal recording paper should have is (
1) High-quality recorded images can be obtained. (2) The obtained recorded image does not lose its color due to the influence of external conditions such as humidity and heat.

Among these, this is a serious drawback in practical use as silver paper for recording recorded images, and various proposals have been made to improve this drawback. .

Special Publication @11-JJf No. 4 discloses the addition of phenol derivatives such as co-methylene bis(tei-methyl-6-1art-7' tylphenol), JP-A-Sho JJ-/
In No. 774A7, water-insoluble modified phenolic resin such as rosin modification is added.
No. 2994 describes the addition of a terephthalate ester such as diethyl terephthalate. Also, see the unpublished w8ja-1Of! No. DA describes the use of a mixture of one or more fluoran compounds.

However, these methods have the disadvantage that not only the effect of preventing color fading is insufficient, but also unnecessary fluorochrome, so-called "fog 1", occurs during the production of recording paper or during storage of recording paper. "IKa 1 degree," which increases significantly under the influence of heat, so under such conditions rJ commercial value t-I
L (will be lowered.

An object of the present invention is to provide 1 m of heat-sensitive recording paper which can obtain recording paper of high density, and which is subject to less discoloration due to humidity and heat, without causing the occurrence of obscurity.

The above object of the present invention is to provide a colorless electron-donating dye;
In thermal recording paper containing an organic acid capable of coloring upon contact with the dye, at least one fluoran compound #IIIJ is used as a mosquito dye, and one of them is a fluoran compound represented by general formula (I). 19 was achieved in a thermosensitive recording paper characterized by containing qlJ in an amount of 20% by weight or less on a weight board of all dyes.

[In the formula, R1 and R2 may be the same or different,
Alkyl group, cycloalkyl group, aralkyl group,
Representing an aryl group, R1 and 83 may be connected to form a complex shadow, except when B and R1 are co-associated aryl groups, X represents a halogen atom, and Qualkoxyalkyl group] A fluoran compound having a specific structure represented by the general formula (I), which has been known to be used as a mixture of one or more dyes in thermal recording paper. By mixing and using K at a constant ratio of t%, it is likely that the chromaticity will be improved and the recorded image will be prevented from decoloring (this is impossible to predict).

The amount of the fluoran compound I represented by the general formula (I) to be used is -0 weight t or more based on the total dye.

Less than or equal to the weight, preferably #0 or more and t7 or less, more preferably '*L (t: I, 10 or more and less than 10. If the amount is too large, the melanism will decrease and at the same time, the anti-bleaching effect will also decrease.

Next, specific examples of the fluoran compound represented by the general formula (I) are shown below. (3) J-diethylamino-6-chloro-7-p-anilinofluorane (4) J-diethylamino-6-chloro-7-p-toluidinofluorane (6) t,-diethylamino-6-chloro -7-β-methoxyethylaminofluorane (6) 3-diethylamino-6-chloro-7-p-ethoxyethylaminofluorane (7) J-dibutylamino-6-chloro-7-β-ethoxyethylamino Fluoran (8) Fluoran compounds represented by the general formula (I), including 3-diethylamino-6-chloro-7-β-butoxybutylaminofluoran and mixed with the c1 fluorone compound 0 Particularly limited General formula (I)
It is also possible to use a fluoran compound represented by the general formula ■
Specific examples of fluoran compounds other than general formula (I) include J-diethylamino-7-dipendylaminofluorane, 3-diethylamino-7-octylaminofluorane, and J-diethylamino-7- (Coke chloranilino) fluoran, J-diptylamino-7-(1-chloroani+7/)fluoran, 3-diethyl-6-methyl-7-anirite fluoran, J-biiridino-methyl-7-anirite fluoran , 3-cyclohexylmethylamino-6-methyl-7-anilite fluorane, j-
(N-ethyl-p-toluidino)-6-methyl-7-anilite fluorane and the like are available.

As the organic acid used in the present invention, phenol derivatives and aromatic carboxylic acid derivatives are preferred 11. <Bisphenols are particularly preferred. Concrete vltfJ.

As phenols, p-octylphenol, p-t
ert-butylphenol, p-phenylphenol,
1. l-bis(p-hydroxyphenyl)propane, co-corbis(p-hydroxy7enyl)propane, /,
/-bis(p-hydroxyphenyl)intane, /, l
-bis(p-hydroxyphenyl)hexane, -1λ
-bis(p-hydroxyphenyl)hexane, 1. /-
Examples include bis(p-hydroxyphenyl)-2-ethyl-hexane, co-2-bis(gu-hydroxy-3,!-dichlorophenyl)propane, and the like.

As an aromatic carboxylic acid derivative, p-hydroxyammonyl
Benzyl fomarate, ethyl p-hydroxybenzoate, p-hydroxybenzoic acid [7'thyl, 3. J-di-tert-butylsalicylic acid, J,j-di-α-methylbenzylsalicylic acid, and polyvalent metal salts thereof are used in Carmen W/R.

When producing a simple solution for thermal recording paper, it is necessary to disperse the above-mentioned thermal recording paper material using water as a dispersion medium. At this time, it is preferable to use water-soluble polymers such as polyvinyl alcohol, doxyethyl cellulose, and starch trout conductors.

The dispersion method of 7tJ1g thermal recording material using these dispersion media is generally from /weight/weight to 10weight/@
-St, further g1!1Ftt,,<1wt/l-
From cents! An electron-donating dye or an organic acid (10% by weight to 10% by weight) is added to a dispersion medium containing a water-soluble polymer of e-cents by weight, and then milled using a ball mill, sand 2, attritor, or colloid building. Dispersion is performed using a dispersing machine such as the following.

To the mixture of the above dispersion i[, oil-absorbing pigments, waxes, metal soaps, etc. are further added as necessary to make a logical liquid for thermal recording paper, and spread on a support such as paper or plastic cape. , to obtain the desired thermal recording paper, oil-absorbing pigments include kaolin, calcined kaolin, Merck, waxite, diatomaceous earth, calcium carbonate, aluminum hydroxide, and hydroxide! Gnesium, carbonic acid! The filler is selected from magnesium, titanium oxide, barium carbonate, urea-formal phosphorus, and cellulose filler.

As waxes, in addition to lamp wax, paraffin wax, cownapa wax, microcrystalline wax, and polyethylene wax, higher fatty acids such as stearic acid amide, ethylene bisstearamide, and higher fatty acid esters can be used.

Examples of the metal soap include higher fatty acid polyvalent metal salts such as zinc stearate, aluminum stearate, calcium stearate, and zinc oleic acid.

Examples will be shown below, but the present invention is not limited to 1jQt;r/f'LK.

Example l J-diethylamino-6-chloro-7-β-ethoxyethyl aminofluorane 20 if/0-polyvinyl alcohol (degree of saponification 9, degree of polymerization 100) aqueous solution 10
A dispersion liquid (A) was obtained by dispersing the mixture with 0 g in a VCJOO ball mill overnight. Similarly [j-Siechilua 1)-7-(
KJOO-
Dispersion was carried out day and night in a ball mill to obtain a dispersion (B). Similar [2, J-bis(hydroxyphenyl)propane 1
077 and stearic acid OII in io1! Polyvinyl alcohol water 1111i[/Oall and KJ
Dispersion was carried out overnight in an OO-ball mill to obtain a dispersion (D). The inside of the dispersion and the dispersion @) are mixed at a weight ratio of f70:JO to obtain a dye mixed dispersion L). Further, zog calcium carbonate mold powder was added to the mixed liquid JOOIIK and sufficiently dispersed to prepare a coating liquid.

For thermal recording paper, apply with a near knife so that a coating amount of 4117 series 2 is obtained on the base paper having a basis weight of tlt JOI / 2. Dry for 0 °CJ minutes,
A thermosensitive recording paper was obtained.

Example ! Mixing ratio between the dispersion liquid of Example 1 and the dispersion liquid: 10
A thermosensitive recording paper was obtained in the same manner as in the previous example, except that the mixed dispersion liquid was obtained at a weight ratio of t-.

Example 3 Mixing ratio of dispersion liquid and dispersion liquid f3)
In addition to obtaining a mixed dispersion n with a weight ratio of near 0, Example 1
Similarly, thermal recording paper was obtained.

Example 4 Vt in place of J-diethylamino-7-(no-chloroanilino)fluoran JoIi in Example 1, J-dibutylamino-7-(--chloroanilino)fluoran o
, 9 to obtain a dispersion (B10), and in addition to obtaining a dispersion (B10) using Kl as in Example 1, thermal recording paper T- was obtained.

Example S Example! The same procedure as in Example 1 was used except that a dispersion of 2,3-cyclohexylmethylamino-6-methyl-7-anilinofluoran was used instead of 3-diethylamino-7-(λ-chloroanilino)fluoran 20770. And then I got a passionate story in Kamakura.

Example 6 3-diethylamino-6-chloro-7-β- of Example 1
Ethoxycetylaminofluorancho. K, J instead of l
-Diethylamino-6-chloro-7-anilinofluorane JO11 was used to obtain dispersion 1 [@], and a thermosensitive recording paper was obtained in the same manner as in the several layers.

Example 7 J-diethylamino-6-chloro-7-β- of Run N1
Ethoxyethyla ζnofluorane Jog) instead of
-Diethylamino-6-chloro-7-anilinofluorane JOIIt- to obtain a dispersion -re, DKs'-diethylamino- instead of J-diethylamino-7-(Coke chloranilino)fluorane 209 of Example 1 6-chloro-7-β-ethoxyethylaminofluorancot
tt was used to obtain a dispersion liquid. In addition, a thermosensitive recording paper was obtained in the same manner as in Example 1.

Comparative example! Dormitory mN1 J-diethylamino-Todoroki-chloro7-β-
Ethoxyethylaminofluorane J7 instead of J0I,
J-(N-ethyl-p-toluidino)-≦-methyl-7
-A thermosensitive recording paper tlI was prepared in the same manner as in Example 1, except that a dispersion of illumination was obtained using anirite fluoran 2011f.

Comparative IPIl Lazy Example/J-diethylamino-6-chloro-7-l-
Ethoxyethylaminofluorane ai[(4) and dispersion (D) were mixed at a weight ratio of kJ:JO, and the following Example 1
The thermal recording paper t@+ was prepared in the same manner as above.

Comparative Example 1 811181 (DJ-diethylamino-6-chloro-7
- Instead of β-ethoxyethylaminofluoran 077, J-diethylamino-6-chloro-7-anilinofluoran-oI was used to prepare the dispersion. Dispersion liquid (A
A Jt dispersion solution was mixed at a weight ratio of 3:0, and heat-sensitive recording paper was obtained in the same manner as in the following examples.

Comparative Experiments Comparative experiments on the thermal recording papers obtained in Examples and Comparative Examples were conducted as follows.

(1) Capri and chromogenic main running Kaya! Dot/■, sub-scanning 6 dots/■, J
rrts/dot, j OmJ/■2 energy is given to the Kibrass element and recorded, Macbeth RD-jtil
The T-type reflection density needle (visual filter used) detects fog (ground density before recording) and coloring matter density C after recording.
The initial density f) was measured.

(2) Moisture resistance Chromophore tjO@c obtained in a chromogenic test.

KHfO@'s #IokikachuKJ4! After leaving it for one hour, fog (ground density) and ft of the color material were measured.

In addition, the residual rate of the chromophore was calculated using the following formula.

(3) Color material @io”c%RH coo% obtained in heat-resistant coloring test
Fog (concentration of ground) after being left in an atmosphere for an hour.
and the chromophore concentration was measured. In addition, the residual rate of the rc chromophore was calculated using the following formula.

Hiho test result t#! / Shown in the table.

Claims (1)

[Claims] A heat-sensitive recording paper containing a colorless electron-donating dye and an organic acid capable of coloring upon contact with the dye, wherein at least one fluoran compound is used as the dye. Thermal paper has a 1* image and contains a fluoran compound represented by the general formula (I) as one of them in an amount of at least 90% by weight of all the dyes. c In the formula, R1 and R1us may be the same or different, and represent an alkyl group, a cycloalkyl group, an aralkyl group, and a
, aryl group tlI, R8 and B are connected to form complex 1
Even if 11 is formed, if R and R8 are both aryl groups [excluded]. Xfi halogen atom t-represents kL
3σ aryl group or tahaalkoxyalkyl group'kl! t
)f. ]