JPS6089449A - Novel lower aralkyl ester compound and its use - Google Patents

Abstract

NEW MATERIAL:The lower aralkyl ester of formula I [R is lower aralkyl; X is phenoxyphenyl, 6-(lower aralkyloxy)-2-naphthyl or -Y-COOR (Y is group of formula II)]. EXAMPLE:p-(p-Methyl)phenoxybenzoic acid phenylmethyl ester. USE:A compound effective to prevent the color fading and bleaching phenomenon of a heat-sensitive recording paper. PREPARATION:The compound of formula I wherein X is X<1> can be produced e.g. by the direct esterification of the aralkyl alcohol of formula R-OH with the carboxylic acid of formula X<1>-COOH[X<1> is phenoxyphenyl, 6-(lower aralkyloxy)- 2-naphthyl or -Y-COOH].

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to novel lower aralkyl esters and methods of use thereof.

Advances in electronics have led to remarkable advances in recording devices, and thermal recording paper has become widespread in a wide range of applications, including thermal pen recorders for various measuring instruments, thermal printers for computers, thermal automatic ticket vending machines, and facsimile machines. In particular, information-related devices such as facsimiles are required to have high-speed recording performance, and the thermal recording paper used therein must also have the ability to quickly produce dense recorded images.

Thermal recording paper is made by coating a color forming agent and a color developer on a support, but in order for the thermal recording paper to have the above performance, the color developer must dissolve with a small amount of heat and cause a color reaction. is necessary. Among the phenolic compounds that are often used as color developers, phenolic compounds are suitable for high-speed thermal recording.
Para-hydroxybenzoic acid esters, especially para-hydroxybenzoic acid benzyl esters, are known (Japanese Patent Application Laid-Open No. 1983-1979-1).
No. 140483, No. 56-144193, No. 57-8
20.89 and 57-107883)
.

Thermal recording paper containing these color developers has many features such as good color development performance, high density and clear recorded images, and little background fog. However, the stability of the recorded image after color development is not necessarily sufficient, and it is known that fading and whitening phenomena occur in the color recorded image. Although the reason for this is not clear, it is thought that the discoloration or whitening phenomenon occurs due to detachment and crystallization of the parahydroxybenzoate from the charge transfer complex between the color former and the parahydroxybenzoate. In order to prevent this crystallization, methods of adding certain compounds are known, but satisfactory results have not always been obtained.

In view of these circumstances, the inventors conducted research and found that
We have succeeded in obtaining a compound that can prevent color fading or whitening phenomenon in thermal recording paper.

The present invention is based on the general formula % formula % (1) (wherein R is a lower aralkyl group, ) is a lower aralkyl ester represented by

Further, the present invention is a heat-sensitive recording paper having a heat-sensitive layer containing a colorless to light-colored color former, a color developer that causes this substance to develop color when heated, and a compound of formula 1.

The compound of formula I is a novel compound not yet described in the literature, and can be prepared by using the esterification and etherification reactions described below.

(1) Aralkyl alcohol represented by the general formula % formula % () (wherein R has the above meaning) (wherein X1 is a phenoxyphenyl group, 6-lower aralkyl Direct esterification reaction with a carboxylic acid represented by a 2-naphthyl group or a group -Y-COOH, Y having the meaning given above.

(2) A dehydrogenation reaction between an aralkyl halide represented by the general formula %formula%() and an alkali salt of a compound represented by the formula (■).

(6) Transesterification reaction between an aralkyl alcohol of formula (■) and an alkyl ester of a compound of formula I.

+4) 2-H) A method of reacting an alkali salt of roxynaphthalene-6-carboxylic acid with a compound of formula 1v to carry out esterification and etherification reactions.

(5) A method in which an alkali salt of nitrobenzoic acid is reacted with a compound of formula 1v and the resulting product is etherified.

Compounds of formula I include, for example, paraphenoxybenzoic phenylmethyl ester, para(paramethyl)phenoxybenzoic acid phenylmethyl ester, para(orthophenyl)phenoxybenzoic acid phenylmethyl ester, para(paraphenyl)phenoxybenzoic acid phenylmethyl ester, 2-Phenylmethoxy-naphthalene-6-carboxylic acid phenylmethyl ester, 2-paramethylphenylmethoxy-naphthalene-6-carboxylic acid phenylmethyl ester, 2-phenylmethoxy-naphthalene-6-
Carboxylic acid-halamethyl-phenylmethyl ester, 2
-paramethylphenylmethoxy-naphthalene-6-carboxylic acid-paramethyl-phenylmethyl ester, 4.4
Examples include '-ethylenedioxy-bis-benzoic acid diphenylmethyl ester and 4,4'-ethylenedioxy-bis-benzoic acid-di(paramethyl)-phenylmethyl ester.

When producing the thermal recording paper of the present invention, first, a color forming agent, a color developer, and a compound of formula I are blended. The blending ratio is preferably 100 parts by weight of the color developer to 100 parts by weight of the color former.
It is 1000 parts by weight. The compound of formula I is preferably used in an amount of 1 to 200 parts by weight per 100 parts by weight of the color developer. Examples of colorless to light-colored coloring agents include leuco dyes such as phthalide and fluoran, such as crystal violet lactone, Benzoylleucomethylene blue, 3-diethylamide/-6-methyl-7-anilite fluorane, 3
-diethylamine-6-methyl-7-chlorofluorane, 3-(N-cyclohexyl-N-methylamine,).

-6-methyl-7-anilite fluoran, 3-diethylamine-7-(ortho-chloroanilino)fluoran,
3'-(N-ethyl-paratoluidino)-6-methyl-
7-Anilitunluorane, 6-diethylamine-7-[
Meta(trifluoromethyl)anilino]fluorane, 6
-diethylamino-6-methyl-7-(ordop-p-dimethylanilino)fluoran, 6-pyroIJ,)nor-6-methyl-7-anilinofluorane, 6-piperidino-6-methyl-anilinofluorane, 6 -diethylamine-6-methylfluorane, 6-cyclobenzylamino-6-chlorofluorane, and the like.

g As the coloring agent, parahydroxybenzoic acid esters such as methyl parahydroxybenzoate, -ethyl, -furobil, -isopropyl, -butyl, -isobutyl, -hexyl, -benzyl, -phenethyl, -phenyl, -naphthyl, etc. It will be done.

These materials are atomized using water as a medium using a grinder such as a ball mill, attritor, or sand grinder, or a suitable emulsifying device, and various additive materials are added depending on the purpose to form a coating liquid.

Additive materials include polyvinyl 7/L/coal, hydroxyethyl cellulose, methyl cellulose, starches,
Binders such as styrene-maleic anhydride copolymer, vinyl acetate-maleic anhydride copolymer, styrene-butadiene copolymer, kaolin, diatomaceous earth, talc, titanium oxide,
Fillers such as calcium carbonate, magnesium carbonate, aluminum hydroxide, excipients such as fatty acid metal salts such as zinc stearate, aluminum stearate, calcium stearate, zinc oleate, waxes such as paraffin wax, cowna wax, Examples include lubricants such as polyethylene wax, benzophenone-based and triazole-based ultraviolet absorbers, water-resistant agents such as glyoxal, dispersions, and antifoaming agents.

The heat-sensitive recording paper of the present invention can be obtained by applying a coating solution containing these additive materials to a support such as paper or film.

The heat-sensitive recording paper of the present invention has good color development, high-speed recording performance, and background stability, and furthermore, fading and whitening of recorded images are improved and stability is excellent.

Example 1 Synthesis of para-phenooxybenzoic acid phenylmethyl ester para-nitrobenzoic acid 83.1? (0.5 mol) and sodium carbonate 26.59 (0.5 mol) and dimethyl formaldehyde 250. ! i+ was added and stirred at room temperature for 0.5 hour. Next, phenylmethyl chloride was added dropwise while stirring for 0.5 hour, and the mixture was further heated at 100° C. for 6 hours. After the reaction, dimethyl formaldehyde is distilled off and p
Liquid separation was carried out using toluene and water adjusted to H10. Furthermore, the toluene layer was washed with water, the toluene was distilled off, and the obtained crude crystals were recrystallized from methanol to give pale yellow crystals with a melting point of 84.6 to 856°C.
2.7 g (yield 87%) was obtained.

7.5.9 g of dimethyl formaldehyde was added to 14.1 g (0.15 mol) of phenol, and then a sodium hydride solution was added, followed by stirring at room temperature for 0.5 hour. After the reaction,
Paranitrobenzoic acid phenylmethyl ester 25.71
/ (0,1 mo/I/) was added and heated at 100° C. for 6 hours. After the reaction, ether extraction was performed, water was added to the ether layer, the pH was adjusted to 12 or higher, and liquid separation was performed. After washing the ether layer with water, the ether was distilled off, and the resulting crude crystals were recrystallized from ethanol to a melting point of 66.4-67.9°C.
Colorless crystals of 11. +1' (45% yield) was obtained.

Elemental analysis value: CH as C20) 11603 Theoretical value (%) 78.96 5.30 Experimental value (%l) 79.05 5.28 Example 2 Synthesis of 2-phenylmethoxy-naphthalene-6-carboxylic acid phenylmethyl ester 2-Hydroxy-naphthalene-6-carboxylic acid 188.
2. ! 7 (1,0 mol), sodium carbonate 212,0
g (2,0 mol) and phenylmethyl chloride 253
．． 29 (2.0 mol) with dimethyl formaldehyde 4
70.5.9 was added and heated at 100°C for 6 hours. After the reaction, dimethyl formaldehyde was distilled off, a toluene-water mixture was added, and the mixture was separated at 70°C. Next, the toluene layer was washed with an alkali and water, then a toluene-water mixture was added again, the liquid was separated at 70°C, and the toluene layer was cooled and then heated to obtain colorless crystals with a melting point of 96.7 to 98.0°C. 332
．． ! 9 (yield 90%) was obtained.

Elemental analysis value: CH as C25H2oO3 Theoretical value (%) 81.50 5.47 Experimental value (%) 81.41 5.51 Example 6 4.4'-Ethylenedioxy-bis-benzoic acid-diphenylmethyl ester Synthesis 4. 4'-Ethylenedioxy-bis-benzoic acid-dimethyl ester 66.051 (0.2 mol) Tophenylmethyl alcohol 86.49 (4.0 mol) Nidibutyltin oxide 1.32.9 The mixture was heated at 190 to 200° C. for 2 hours while methanol was distilled off. After the reaction, dibutyltin oxide was distilled off, and the resulting crude crystals were recrystallized from acetone to obtain colorless crystals with a melting point of 108.5 to 11[] and a temperature of 2°C, 50.8.9% (yield: 77%). Ta.

Elemental analysis value: C'H as C3o H2O0e Theoretical value (%) 74.67 5.46 Experimental value (%) 74.49 5.48 Example 4 Liquid A (dye dispersion) 6-(N-cyclohexyl-N -Methylamino)-6-methyl-7-anirite fluorane 4.0 parts 10% polyvinyl alcohol bath solution 9.2 parts Water 5.
0 parts Liquid B (color developer dispersion) Parahydroxybenzoic acid benzyl ester 6.0 parts Paraphenoxybenzoic acid phenylmethyl ester 0.6 parts 10% polyvinyl alcohol water bath liquid 50.0 m Grind the can liquid with the above composition in a ball mill. Mix.

Next, a coating liquid was prepared by mixing 1.0 part of liquid A and 4.0 parts of B i , and this coating liquid was coated on high-quality paper using a wire bar to obtain thermal recording paper (coating amount: 6⁄2). m2
).

Example 5 A thermosensitive recording paper was obtained in the same manner as in Example 4, except that phenylmethyl para-(orthophenyl)phenoxybenzoate was used instead of phenylmethyl para-phenoxybenzoate in Solution 40B.

Example 6 A thermosensitive recording paper was obtained in the same manner as in Example 4, except that para-(para-phenyl)phenoxybenzoic acid phenylmethyl ester was used instead of para-phenoxybenzoic acid phenylmethyl ester in Example 40B solution.

Example 7 Thermosensitive recording paper was obtained in the same manner as in Example 4 except that 2-phenylmethoxy-naphthalene-6-carboxylic acid phenylmethyl ester was used instead of paraphenoxybenzoic acid phenylmethyl ester in Example 40B solution. .

Example 8 2-paramethylphenylmethoxy-naphthalene-6-carboxylic acid-halamethyl-phenylmethyl ester was used instead of paraphenoxybenzoic acid phenylmethyl ester in Example 40B solution, and the other conditions were the same as in Example 4. I got the recording paper.

Example 9 Using 4,4′-ethylenedioxy7-bis-benzoic acid diphenylmethyl ester instead of phenoxybenzoic diphenylmethyl ester in Example 40B solution,
A thermosensitive recording paper was obtained in the same manner as in Example 4 in other respects.

Comparative Example 1 A thermal recording paper was obtained in the same manner as in Example 4 except that panphenoxybenzoic acid phenylmethyl ester was not used in the Example 40B solution.

Comparative Example 2 4,4'-methylene/-bis-(2,6-tert-butylphenol), which is a type of commercially available image preservative, was used instead of paraphenoxybenzoic acid phenylmethyl ester in Example 40B solution, and other A thermosensitive recording paper was obtained in the same manner as in Example 4.

Test Example 1 The background density and the image density when colored at 120° C. were measured for 106 types of thermal recording paper in Examples 4 to 8 and Comparative Example. Further, the heat-sensitive recording paper after color development was left for 24 hours at 40° C. and 90% humidity or 60° C., and changes in background density and image density were measured. The results are shown in Table 1.

Test Example 2 Examples 4 to 8 and Comparative Examples 106 kinds of thermal recording paper were colored at 120° C., then left for 24 hours under harsh conditions of 6D'C1 humidity of 90%, and changes in image density were measured.

The results are shown in Table 2.

Table 2 *20: Almost no change x: Crystals precipitate white or are mottled Discoloration Test Example 6 Example 9 and Comparative Examples 1 to 206 types of thermal recording paper were colored at background density and 120°C. The image density at the time was measured. Further, the heat-sensitive recording paper after color development was left for 24 hours under harsh conditions of 60° C. and 90% humidity, and changes in background density and image density were measured. The results are shown in Table 6.

Table 6 *20: Almost no change ×: Crystals precipitate white or discolor in spots

Claims (1)

[Claims] 1. A lower aralkyl ester having the general formula % representing a nyl group, a 6-lower aralkyloxy-2-naphthyl group, or a group -Y-COOFL, where Y is represented. 2. A colorless to light-colored coloring agent, a coloring agent that causes this substance to develop color when heated, and a general formula (%) (in the formula, R is a lower aralkyl group, X is a phenoxyphenyl group, 6-[Jl aralkyloxy A thermosensitive recording paper having a thermosensitive layer containing a lower aralkyl ester having a -2-naphthyl group or a group -Y-COOR and represented by Kokoro.