JPH0331233A - Benzyloxymethyl biphenyl ether and coloring accelerator for heat-sensitive recording material - Google Patents

Abstract

NEW MATERIAL:Benzyloxymethyl biphenyl ether expressed by formula I. EXAMPLE:Benzyloxymethyl 4-biphenyl ether. USE:A coloring accelerator for heat-sensitive recording materials, having a lower melting point and better solubility than those of both or either of leuco dyes and organic acidic substances constituting heat-sensitive coloring layers and capable of providing heat-sensitive recording materials having excellent heat responsiveness and heat resistance. PREPARATION:Benzyl alcohol expressed by formula II is reacted with formaldehyde expressed by formula III and an anhydrous hydrogen halide gas expressed by the formula HX (X is halogen of Cl, Br or I) to provide a benzylhalogenomethyl ether expressed by formula IV, which is then reacted with hydroxybiphenyl expressed by formula V in the presence of NaOH in a solvent, such as a mixed solvent of tetrahydrofuran and water, to afford the compound expressed by formula I.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a novel compound, which is useful as a color accelerator for heat-sensitive recording materials.

[Conventional technology]

In recent years, the amount of information has increased with the diversification of information, and various recording methods and recording materials have been researched and put into practical use in the field of information recording for recording this information. Among them, the heat-sensitive recording method is: - A recorded image can be obtained by simply heating the heat-sensitive recording material, and no complicated development process is required. - The manufacturing and storage management of heat-sensitive recording materials is better than that of other recording materials. In many cases, inexpensive paper is used as a support for heat-sensitive recording materials, but in this case, it has the advantage that the resulting recording material has a feel similar to that of plain paper. Yes, computer output, printers such as calculators, recorders of various measuring instruments,
It is used in many fields such as facsimiles, automatic ticket issuing machines, and thermal copying machines.

Heat-sensitive recording materials used for these purposes have conventionally contained leuco dyes that are colorless or light-colored at room temperature and organic acidic substances such as phenolic compounds that react with the leuco dyes to develop color when heated. It is known that a heat-sensitive coloring layer is provided on a support such as paper, synthetic paper, synthetic resin film, etc.
0 and Special Publication No. 4514, No. 039).

However, these conventional heat-sensitive recording materials have a problem in that their thermal responsiveness is insufficient and sufficient color density cannot be obtained when used for high-speed recording. In the field of information recording as well, it is possible to heat the thermal head in a short time and produce sufficient density with a low voltage, thereby increasing the recording speed and making it compatible with high-speed recording. It is requested.

Therefore, in an attempt to solve these problems with conventional heat-sensitive recording materials, it has been proposed to add a thermofusible substance to the heat-sensitive coloring layer to improve the thermal responsiveness ( JP-A No. 51-27.599 and JP-A No. 4
8-49.231). However, even with such technology, since the demand for high-speed recording has become even higher in recent years, a sufficiently satisfactory result regarding the thermal responsiveness has not yet been obtained.

[Problem to be solved by the invention]

Therefore, the present inventors have discovered that the leuco dye and organic acidic substance can be added to the thermosensitive coloring layer of a thermosensitive recording material to promote color development by the leuco dye and organic acid substance in the thermosensitive coloring layer, thereby achieving excellent thermal responsiveness. As a result of extensive research on color development accelerators that can provide heat-sensitive recording materials with The present invention was achieved based on the discovery that the present invention has the following properties.

It is therefore an object of the present invention to provide new compounds benzyloxymethyl biphenyl ether.

Another object of the present invention is to provide a color development accelerator that can be added to a heat-sensitive coloring layer in order to obtain a heat-sensitive recording material having excellent thermal responsiveness.

[Means to solve the problem]

That is, the present invention relates to a benzyloxymethyl biphenyl ether represented by the following formula (1), and the present invention relates to a color development accelerator for heat-sensitive recording materials comprising the benzyloxymethyl biphenyl ether represented by the above formula (1). It is.

This benzyloxymethyl biphenyl ether is produced by reacting benzyl alcohol with formaldehyde and anhydrous hydrogen halide gas to form benzyl halogenomethyl ether, as shown in the reaction formula below, and then reacting it in the presence of sodium hydroxide in an appropriate solvent. It can be obtained almost quantitatively by reacting with hydroxybiphenyl under heating and reflux.

QcH,on + HCHO+ HX -Qcn,oc
u, xQ-CLOCH,X + <OishiOH (however,
Among the benzyloxymethyl biphenyl ethers produced in this way, particularly preferred is the reaction between benzyl chloromethyl ether and 4-hydroxybiphenyl. This product is benzyloxymethyl-4-biphenyl ether, which has a melting point (mp) of 83°C and is suitable as a coloring accelerator added to the heat-sensitive coloring layer of heat-sensitive recording materials. It is.

In addition, in the present invention, the leuco dye used as a coloring agent is colorless or light-colored at room temperature, and is a substance that develops color by reacting with an acidic substance under heating.
triallylmethane dyes such as p-dimethylaminophenyl)-6 dimethylaminophthalide, and 4.4°-bis-
Diphenylmethane dyes such as dimethylaminobenzhydridobenzyl ether, thiazine dyes such as benzoylleucomethylene blue, spiro dyes such as 3-methyl-spiro-dinaphthopyran, and other fluoran dyes.
Examples include leucoauramine dyes, indoline dyes, indigo dyes, and the like.

The organic acidic substance used together with the leuco dye is a substance that becomes a color developer when it comes into contact with the leuco dye when heated, and includes various phenolic compounds and organic acids. The organic acidic substance used for this purpose is preferably one that is solid at room temperature and liquefies or vaporizes at 50°C or higher. Specific examples of such substances include, for example, phthalic anhydride, gallic acid, salicylic acid, 4,4-isopropylidene (2-t-butylphenol), 4.4°
-5ee-butylidenephenol, 4,4°-(1-methyl-〇-hexylidene)diphenol, 4-phenylphenol, 4-hydroxydiphenoxidemethyl-4
-Hydroxybenzoate, 4-hydroxyacetophenone salicylic acid anilide, 4,4-cyclohexylidene diphenol, 4.4°-cyclohexylidene bis(2
-methylphenol), 4.4°-benzylidenephenol, 4,4°-thiobis(6-t-butyl-3-methylphenol), novolac type phenolic resin, halogenated novolac type phenolic resin, α-naphthol,
Examples include β-naphthol.

The benzyloxymethyl biphenyl ether of the present invention has a melting point lower than both the leuco dye and/or the organic acidic substance, has solubility in the leuco dye and/or the organic acidic substance, and has a solubility in the leuco dye and/or the organic acidic substance. It acts as a color development accelerator, that is, it acts as a color development accelerator. The amount of benzyloxymethyl biphenyl ether used as a color development accelerator varies depending on the leuco dye, organic acid substance, and type of benzyloxymethyl biphenyl ether used, but it is usually 0. 5
~30 parts by weight, preferably 1 to 10 parts by weight.

Furthermore, various additives can be added to the heat-sensitive recording material of the present invention depending on its use.

Examples of such additives include polyvinyl alcohol (PVA), methylcellulose, carboxymethylcellulose, polyacrylic acid, which isolates and fixes the leuco dye and organic acidic substance dispersed in fine particles from each other.
binders such as casein, gelatin, starch or their derivatives, the whiteness of the heat-sensitive coloring layer, the slipperiness of the writing instrument,
White pigments such as calcium carbonate, kaolin, clay talc, and titanium oxide, as well as aliphatic metal salts, are added for sticking purposes. These additives are mixed or applied separately to a support such as a paper film to form a thermosensitive coloring layer.

[For production]

When the benzyloxymethyl biphenyl ether of the present invention is used as a color development accelerator in a heat-sensitive coloring layer of a heat-sensitive recording material, this benzyloxymethylbiphenyl ether is a leuco dye and an organic acid substance constituting this heat-sensitive coloring layer. It has a lower melting point than either or both of these leuco dyes and exhibits excellent solubility in both these leuco dyes and/or organic acidic substances, thereby inhibiting the reaction between these leuco dyes and organic acidic substances. This is considered to be a promotion.

〔Example〕

The present invention will be specifically described below based on Examples and Comparative Examples.

Example 1 108g of benzyl alcohol and 3 parts of paraformaldehyde
3 g was added thereto, and anhydrous hydrogen chloride gas was blown into the solution over a period of about 2 hours while maintaining the temperature at 20 to 25° C. to cause a slow reaction. After the reaction was completed, the reaction mixture was allowed to stand still to separate into two layers, and the upper layer was separated.

Next, 117 g of 4-hydroxybiphenyl and 138 g of sodium hydroxide were mixed in 30 g of tetrahydrofuran (THF).
The above-mentioned upper layer was added dropwise to this solution, and after the dropwise addition was completed, the mixture was heated and reacted under reflux for about 2 to 3 hours.

After the reaction, the reaction mixture was allowed to stand, the organic layer and the aqueous layer were separated, THF in the organic layer was distilled off under reduced pressure, and the resulting residue was recrystallized from ethanol to give benzyloxymethyl-4- 167 g of biphenyl ether (melting point 83°C) was obtained.

The results of NMR analysis (400MH2) performed on the obtained benzyloxymethyl-4-biphenyl ether are shown below.

'H-NMR (CDC13): δ (ppm) near, 55
(2H, d, J=8.3Hz).

7.52 (2H, d, J=8.8H2).

7.41 (2H, dd, J=7.3 &?, 8H2
).

7.29-7.35 (6H, m).

7.16 (28, d, J=9.0H2).

5.32 (21, s), 4.74 (2H, s) Also,
The results of infrared absorption spectrum analysis (KBr) are shown in FIG.

Example 2 Using benzyloxymethyl-4-biphenyl ether synthesized in Example 1 above, a thermosensitive recording paper was prepared in the following manner, and its performance was measured.

(Preparation of 11A solution 3-(N-cyclohexyl-N-methylamino)-6-
15 parts by weight of methyl-7-ayurifluorane, 50 parts by weight of benzyloxymethyl-4-biphenyl ether,
A solution A was prepared by pulverizing and mixing 500 parts by weight of a 10wtX-PVA aqueous solution for 24 hours in a ball mill.

(2) Preparation of liquid B 75 parts by weight of bispheno-/1zA and 15wtX-PV
Solution B was prepared by pulverizing and mixing 500 parts by weight of aqueous solution A with a ball mill for 24 hours.

(3) Preparation of thermal recording paper Prepare a coating liquid by mixing 100 parts by weight of liquid A and 100 parts by weight of liquid B. This coating liquid is applied onto base paper and dried. After drying, the coating amount is 5 g/ A thermosensitive recording paper of lrr was obtained.

The heat-sensitive recording paper thus obtained was subjected to a color development test and a heat resistance test. The results are shown in Table 1.

The color test was conducted using a stamp-type color tester at 60~
The color was developed in a temperature range of 120° C., and the color density was measured using a reflection densitometer (Sakura Digital Reflection Densitometer PDA45).

Comparative Example 1 A thermosensitive recording paper was prepared in the same manner as in Example 2 above, except that the benzyloxymethyl-4-biphenyl ether was not added during the preparation of Liquid A. Similarly, a color development test and a heat resistance test were conducted. The results are shown in Table 1.

Table 1

[Brief explanation of drawings]

Figure 1 shows benzyloxymethyl-4- obtained in Example 1.
Infrared absorption spectrum analysis of biphenyl ether (KBr
) is a graph diagram showing the results.

Claims (2)

[Claims] (1) The following formula (1) ▲There are mathematical formulas, chemical formulas, tables, etc.▼(1) Benzyloxymethyl biphenyl ether represented by (2) A color accelerator for heat-sensitive recording materials consisting of benzyloxymethyl biphenyl ether represented by the following formula (1) ▲Mathematical formulas, chemical formulas, tables, etc.▼(1)