JPS60187588A - Thermal recording paper - Google Patents

Abstract

PURPOSE:To obtain a thermal recording paper having excellent color forming sensitivity, moisture decoloring resistance and oil resistance and accompanied by little ground fogging, by incorporating a specified fluoran compound as a color former in a thermal color forming layer. CONSTITUTION:At least one fluoran compound of general formula 1 is incorporated. The fluoran compound is substantilly colorless per se, but on making contact with an electron-acceptive substance, it rapidly forms a color. In general formula 1, each of R1 and R2 is H, straight-chain or branched 1-8C alkyl, cyclohexyl, subst. or unsubst. phenyl or subst. or unsubst. benzyl, R3 is H, Cl, F, lower fluoroalkyl, acyl, alkoxy, alkoxyalkyl or straight-chain or branched 1-8C alkyl, R4 is straight-chain or branched 1-8C alkyl, cyclohexyl, subst. or unsubst. phenyl or subst. or unsubst. benzyl, and (n) is an integer of 1-8.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a thermal recording paper characterized by containing at least one type of novel fluoran compound as a color former (11L child-donating coloring agent).

Thermosensitive recording paper is a type of recording paper in which a so-called thermosensitive coloring layer that develops color when heated is formed on a support such as paper. Printers, etc. are used in printers, etc. Compared to other types of recording paper, recording paper with a heat-sensitive coloring layer (1-1) is cheaper, produces less noise, and can record in a shorter time. Due to the advantages of being able to use facsimile,
Widely used in printers, etc. The most important thing about thermal recording paper is that it has a color development sensitivity of 1, but recently it has also begun to be used for POS (point of sale) labels, etc., and the preservation of colored images is good. has become an essential condition.

Characteristics that should be possessed as a minimum for the coloring layer of thermal recording paper 111 (
is excellent in self-coloring resistance (i1+1 background fog), pressure coloring resistance, coloring sensitivity, moisture decoloring resistance, heat decoloring resistance, oil resistance, and light resistance, and currently these are fully satisfied. I haven't gotten what I want. A color former that produces a black color is often used in the heat-sensitive coloring layer, but fluoran compounds as color formers are disclosed in Japanese Patent Publication No. 51-23204, Japanese Patent Publication No. 51-29180, and Japanese Patent Publication No. 56-1983. No. 52759, JP-A No. 57-53562,
JP-A-58-7455 and [JSP-568159
It is disclosed in Publication No. 0, etc. Also color former
Regarding thermal recording paper using 14 Kosho 43-416
No. 0, Special Publication No. 1973-3680 and Special Publication No. 49-17
No. 748 Publication 1 [What is known?

The present inventors used a known fluoran compound as a color former to produce thermal recording paper according to a conventionally known method or the method described in each of the above-mentioned patent publications.
When tested regarding the performance aspects that a thermosensitive recording paper should have, each of these thermosensitive recording papers had drawbacks such as coloring sensitivity, moisture decoloring resistance, oil resistance, and background fog on one side.

The present inventors have developed a thermal TFT that has improved these drawbacks.

As a result of intensive studies on paper, it was found that the performance as a thermal recording paper can be improved to make it more comfortable to wear by using a specific fluoran compound.

That is, the present invention provides the following general formula (1), (wherein, RI,
R2 is each a hydrogen atom, a linear or branched alkyl group having 1 to 8 carbon atoms, a cyclohexyl group, an optionally substituted phenyl group, or i? Represents a benzyl group which may be substituted with 1, and 1 and 3 represent a hydrogen atom, a salt iRJAj atom, a fluorine atom, a lower fluoroalkyl-A- group, an acyl group, an alkoxy group, an alkoxyalkyl group, or a group having 1 to 1 carbon atoms. 8
represents a straight-chain or branched alkyl group having 1 to 8 carbon atoms, a cyclohexyl group, a phenyl group that may be substituted, or a phenyl group that may be substituted. It represents a good benzyl group, and n represents an integer of 1 to 8. ) contains at least one of the novel fluoran compounds represented by the following as a color former. l+
This is a 11-pack thermal recording paper with a characteristic.

The fluoran compound represented by the general formula (1,) itself is almost bright in color. It has the property of quickly developing color when it comes in contact with IL child-receptive substances. Phenol derivatives such as bisphenol A, p-hydroxyamine 7a! It has a blackish color due to the organic carboxylic acid ester of the benzyl ester.

To illustrate the novel fluoran compound represented by the general formula (1) which is a color 7-ohmer used in the thermal recording paper of the present invention, 2-phenyla is a non-3-ethoxyethyl-6
-diethylaminofluorane, 2-phenylamino-6
-Ethoxyethyl-6-dibutylaminofluorane, 2
-phenylamino-3-ethoxyethyl-6-N-cyclohexyl-N-methylami/fluorane, 2-phenylamino-3-ethoxymethyl-6-diethylaminofluorane, 2-phenylamino-3-ethoxymethyl-
6-dibutylaminofluorane, 2-phenylamino-3-ethoxymethyl-6-N-cyclohexyl-N-methylaminofluorane, 2-phenylamino-3-isocroboxymethyl-6-N-cyclo xyl-I~-methylamino/fluoran, 2-phenylamino-6-ocdoxyethyl-6-N-penzylhemethylaminofluoran, 2-phenylamino-3-butoxybutytb
-6-diethylaminofluorane, 2-phenylamino-3-cyclohexyloxyethyl-6-N-ethyl-N-methylaminofluorane, 2-phenylamino-3-butoxyglobyl-6-N-phenyl- N-inopropylaminofluorane, 2-(2-chlorophenylamino)-5-7'toxypropyl-6-N-phenyl-N-isopropylaminofluoran, 2-(2-chlorophenylamino)-5- Ethoxyethyl-6-N-cyclohexylhemethyl-aminofluorane, 2-(2
-chlorophenylamino)-5-ethoxymethyl-6-
Dibutylaminofluorane, 2-(2-fluorophenylamino)-3-cyclohexyloxybutyl-6-cyclohexylaminofluorane, 2-(2-fluorophenylamino)-6-ethoxyethyl-6-N-4 -Chlorbenzylaminofluoran, 2-(4-ethoxyethylphenylamino)-3-ethoxyethyl-6-diphthylaminofluoran, 2-(4-ethoxymethylphenylamino)-6-ethoxyethyl-6-diethyl Rua ε-nofluorane, 2-(4-ethoxyethylphenylamino)-5-methoxyethyl-6-N-cyclohexyl-N-methylaminofluorane, 2-(4-acetylphenylamino)-5-ethoxyethyl- These include 6-N-octyl-N-methylaminofluorane, 2-(4-ethoxyphenylamino)-3-ethoxymethyl-6-diethylaminofluorane, and the like.

To synthesize the fluoran compound represented by the general formula (1) according to the present invention, the general formula (wherein R3, R4, and n are the same as defined above, and R5
represents a hydrogen atom or a lower alkyl group. ) and a benzophenone derivative represented by the general formula (in the formula, R and R2 are the same as defined above), by condensation of sulfuric acid, phosphoric acid, polyIJ acid, etc. It is obtained by reacting in a solution and then treating in alkaline water. For example, 2-phenylamino-
3-Ethoxyethyl-6-') bimanual aminofluorane can be synthesized as follows.

2-(2-Hydroxy-4-diethylamino)phenylcarbonylbenzate 151 was added to 98% sulfuric acid 1501, and after completely dissolving while keeping at about 8 to 14°C, 2-
Ethoxyethyl-4-methoxydiphenylamine 10t
The reaction polymer was reacted at 20-25 DEG C. for 101171 hours, and the reaction polymer was added with 11 g of ice water and then hydroxylated.) An aqueous solution of II was added to adjust the pH to 11' or higher. The precipitate was collected by filtration.

Toluene 450 and 10% sodium hydroxide aqueous solution 5402 were added to the cake and stirred for 2 hours under rapid flow.The toluene layer was washed with separating water and the toluene was distilled off using steam distillation. The precipitated crystals were collected by filtration, and after washing by adding 150 d of methanol to the cake, the crystals were collected again by filtration. The crystals were dried to obtain slightly pinkish white 2-phenylamino-3-ethoxyethyl-6-diethylaminofluorane 11F. The axis point of this fluoran compound is 1
The temperature was 50.5°C to 152.5°C. In addition, the λmax and molecular extinction coefficient of this compound in a 95% acetic acid solution are 449 nm (1,94X10') and 595 nm.
(1,75×104). A solution obtained by dissolving this product in toluene was colorless and quickly developed color due to bisphenol A, giving it a black color.

Further, as the color developer used in combination with these fluoran compounds, 4-1-butylphenol, 4-phenylphenol, methyl-4-hydroxybenzoate, 4.4'-isoglopylidene diphenol, 4.4 '
-isoglopylidene bis(2゜6-siglomophenol), bis(4-hydroxyphenyl)sulfone, benzyl p-hydroxybenzoate, p-human mixybenzoate De
Conventionally known color developers such as -see-butyl and 3-(ciJ-methylbenzyl)salicylic acid can be mentioned.

In addition, in the thermochromic layer, there is a water-soluble or water-insoluble material for spreading on the support.
``loi'': ``I'l'l'' is used. (Companies include polyvinyl alcohol, methylcellulose, hydroxyethylcellulose, carboxymethylcellulose, ajibiakoum, starch, gelatin, casein, polyvinylpyrrolidone, styrene. There are maleic anhydride co-111 compounds tx, among which 1j is particularly preferred in the present invention.
:jl to [furnace available 1':+7; i i'tll is,
Water soluble h1. It is a liquid medicine, and its representative product is polyvinyl alcohol.

, hta1・1! Thermal coloring 19': If necessary, auxiliary additives such as aluminum hydroxide, calcium carbonate, magnesia, barium sulfate, and nutearin 1'l are added.
Fillers such as ester, i'c, dimethyl terephthalate, dibenzyl terephthalate, β-naphthol benzyl ether, suderic acid amide, benzyl p-<benzyloxybenzoate, etc. , (, is added to improve the clarity of the colored image or one color t
t8 "↓11) Ibi-bound" - It can be pointed.

A-IQ of the invention:j: (Recording paper is manufactured by applying and drying a coating liquid for forming a heat-sensitive coloring layer containing each component arranged in 111S on a support such as paper.Produced in this way The thermal iC recording paper of the present invention is
l Excellent in wet color erasing color erasing property and i+l+ property, j1
! I skin rt% degree is small (less skin fog) 1. [
He was good in every way.

The performance of the thermal recording paper was determined by the following test method. In other words, the color density in terms of background density, color former once decolorized in humidity after color development by heating at each temperature (moisture decolorization resistance), color decolorization density when in contact with castor oil (side 1 oiliness), etc. was measured using a Macbeth J<1]-514 type reflection density detector. Heating coloring using a heating temperature of 60 to 170°C, heating time of 6 seconds, and load of 1002 d using an Iaceta-type Thermotest trial frame (manufactured by the French National Textile Research Institute).
It was conducted under the following conditions. Further, decoloring of the coloring agent after coloring by heating was carried out using a constant temperature and humidity tester.

Next, the present invention will be explained in detail with reference to examples.

Example 1 A mixture having the following composition was separately ground for 6 hours using a paint conditioner (trade name: Red Devil) to prepare liquids (■), (2), and (2).

■? Ik composition 2-phenylamino-3-ethoxyethyl-6-diethylaminofluorane 4 heavy (it's 10% polyvinyl alcohol aqueous solution 547a shell part 5% quenching agent)
San Nopco 1407. San Nopco product) 2 parts by weight ■Liquid ill-formed bisphenol A 6 parts by weight 10% polyvinyl alcohol aqueous solution 2 Opt tt
Parts water 14 parts by weight O liquid n1 Aluminum hydroxide 10 TCKk parts 10% polyvinyl alcohol aqueous solution 203iff 1 part water to! Volume parts of liquid, σ) liquid, 0 liquid and water in a ratio of 3:9:5:5 by weight (i
They were mixed at a ratio of t to obtain a paint for heat-sensitive recording paper J11. This paint was applied to the surface of high-quality paper using a wire bar so that the solid content weight after drying was 5v/i, and the paint was placed in a blow dryer and dried at room temperature to obtain the thermal aC recording paper 0) of the present invention. Ta.

Comparative Example 1 Instead of liquid ■ in Example 1, liquid 0, liquid ■ for Gakuan or [
Comparative thermal recording papers) to (7) were obtained in exactly the same manner except that liquid F] was used.

■Liquid composition 2-Phenylamino-3-methyl-6-diethylaminofluorane 4 Weight + tIX 10% polyvinyl alcohol aqueous solution 64 parts by weight 5% antifoaming agent (Sannobuco 140
7) 2 parts by weight ■Liquid composition 2-phenylamino-6-methyl-6-N-7 chlorohexyl-N-methyl-amino-fluorane 4 parts by weight 10% polyvinyl alcohol aqueous solution 34 parts by weight 5% defoaming (Sannobuco 1407) ' The heat-sensitive recording papers of the present invention and comparative heat-sensitive recording papers prepared in the above manner were tested for coloring sensitivity, moisture decoloring resistance, oil resistance, and background fog.

The results are shown in Table 1.

Actual hli Example 2 Actual hfar 2-phenylamino-3- used in Example i
Ethoxyethyl-6-diethylaminofluorane
') K, 2-phenylamino-3-ethoxyethyl A/
-6-Sibutylaminofluorane, 2-phenylamino-3-ethoxyethyl-6-N-cyclohexyl-N-
Methylaminofluorane, 2-phenylamino-6-ethoxymethyl-6-diethylaminofluorane, 2-phenylamino-6-ethoxymethyl-6-dibutylaminofluorane, 2-phenylamino-3-impropoxymethyl-6 -N-cyclohexyl-N-methylami/
Fluoran, 2-phenylamino-3-octoxyethyl-6-N-benzyl-h-methylamino/fluoran,
2-(2-40ruphenylamino)-1-butoxypropyl-6-N-phenylupeinfurobyl aminofluorane, and 2-(2-fluorophenylamino)-5
- Cyclohexylbu 1,000ru 6-Cyclohexylaminofluorane was used in the same manner as in Example 1, and heat-driving recording paper (
(b) - (Power was obtained. Performance tests of these heat-sensitive IC recording papers of the present invention were carried out in the same manner as in Example 1. The results are shown in Table 1.

Note 1) 6 degrees of the white part of the heat-sensitive coloring layer in the uncolored state.

Note 2) Heating humidity when producing a color density of 1.0. Shows good color development sensitivity at low temperatures.

f-E5) Check the moisture decoloring resistance after color development by heating, and measure the color density (D+) of the color development area after leaving the color development layer + W t O part in an atmosphere of 50°C and 90% relative humidity for 24 hours. Then, color former residual rate (to) = D+ / 1.0 [+
×100 is considered as moisture decoloring resistance.

Note 4) Apply 5% castor oil chloroform solution to polyester film using a film applicator (20μ scale)? After applying 1 layer of castor oil and drying it, apply 1 layer of castor oil on the film.
Colored with a 5 x 1 cm rubber stamp M4 degree 1. Stamp on part D and use a constant temperature and darkness tester at 50℃, 90% phase, and 1 humidity! After 1 hour of treatment, the color density (D2) was measured,
Color forming agent residual rate (f) = 1)2/1.00X 100, which is defined as oil resistance.

The thermal recording paper of the present invention had characteristics such as extremely excellent color development sensitivity, moisture resistance to color fading, O, T, and IN (oiliness), and low background density. Therefore, the thermal recording paper of the present invention It is suitable for various recording fields, especially for VC high-speed HD recording, P
OS Kawa's Heat Sensitive Record A1 (It was durable enough for practical use.

Example 3 In Example 1, 2-phenylamino-3-ethoxyethyl-6
-N-Schiff σhexyl-N-methylaminofluorane 2
Thermal recording paper 0) was obtained in the same manner as in Example 1, using a mixture of parts by weight and 2 hL parts of 2-phenylamino-6-ethoxymethyl-6-dibutylaminofluoride.

The performance test of this Kisuke and one-light thermal recording paper was carried out in the same manner as in Example 1, and the results showed that the background density was 010, the color development sensitivity was 100, the humidity and erasure resistance was 106, and the i4 oiliness was 45.Table 1 Even when compared with the recording papers of Comparative Examples 1 and 2, it showed extremely excellent performance.

Hodogaya Chemical Industry Co., Ltd. Continuation of page 1 @ Inventor Katsumasa Yoshikawa 6-2-3 Oji, Kita-ku, Tokyo Hodogaya Chemical Industry Co., Ltd. Central Research Laboratory

Claims (1)

[Claims] General formula (wherein it, R2 are each a hydrogen atom, a linear or branched alkyl group having 1 to 8 carbon atoms, a cyclohexyl group, an optionally substituted phenyl group, or a substituted R3 represents a hydrogen atom, a salt atom, a fluorine atom, a lower fluoroalkyl group, an acyl-containing (,
Alkoxy group, alkoxyalkyl group, or 1 carbon number
~8 straight chain or branched alkyl group, R4 is a straight chain or branched alkyl group having 1 to 8 carbon atoms, a cyclohexyl group, an optionally substituted phenyl group, or ji
'1' represents an optional benzyl group, and n represents an integer of 1 to 8. 1. A heat-sensitive recording paper containing at least one of the novel fluoran compounds represented by the following as a color former.