JP3025059B2 - Formic ester compound - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a formic acid ester of bis (hydroxyethoxy) benzene which is useful as a sensitizer of a heat-sensitive recording material.

[0002]

2. Description of the Related Art A thermosensitive recording material is usually formed on a support such as paper, synthetic paper, resin film, etc. on a support such as a leuco dye or a colorless or pale-colored coloring material and a coloring material when heated. Color developing system consisting of
A thermosensitive coloring layer in which a sensitizer, a binder and other additives are dispersed.The recording device has a coloring property when a heating element such as a thermal head or a hot pen contacts the thermosensitive coloring layer of the recording material. The substance reacts with the developer to form a black color or the like and is recorded.

[0003] The heat-sensitive recording material has the advantages of being able to record in a shorter time, generating less noise, and being inexpensive than other recording materials. It is widely used as recording material for computers, facsimile machines, telex, ticket vending machines and the like.

Hitherto, as a colorless or pale-colored color-forming substance, for example, a lactone, a lactam or a leuco dye having a spiropyran ring has been used.
Various acidic substances have been proposed, particularly phenolic compounds, for example, bisphenol A, benzyl p-hydroxybenzoate and the like have been used alone or in combination of several kinds. When used, there are drawbacks in that the coloring speed is low, it is difficult to increase the recording speed and the density, and color unevenness occurs.

Attempts have been made to achieve high sensitivity by using a sensitizer, which is a third substance, as a color-forming substance and a color developing agent. For example, various waxes and higher fatty acid amide compounds have been tried. , Terphenyl etc. were used,
Unless these sensitizers are used in a large amount, not only the effect is not sufficiently exhibited, but also the demand for high sensitivity of the heat-sensitive recording material is not sufficiently satisfied, and further, fogging occurs or discoloration occurs during storage. However, it was not satisfactory for practical use.

It has also been proposed to use derivatives of bis (hydroxyethoxy) benzene as these sensitizers. For example, JP-A-63-130550 proposes to use divinyl ether derivatives. JP-A-2-220885 proposes to use a diglycidyl ether derivative, and JP-A-2-17518.
No. 7 proposes to use a diester derivative such as diacetate.

However, even when these bis (hydroxyethoxy) benzene derivatives are used, they are not only insufficient for increasing the sensitivity to cope with a higher recording speed, but also cause background fog. It has drawbacks and is insufficient in storage stability under severe use conditions, and further improvement has been strongly desired.

[0008]

In view of the above situation, the present inventors have conducted intensive studies to find a sensitizer capable of obtaining a heat-sensitive recording material having high sensitivity and good storage stability. Among the bis (hydroxyethoxy) benzene derivatives, the present inventors have found that the formic acid diester compound is significantly more effective as a sensitizer than the acetic acid diester compound, and have reached the present invention.

That is, the present invention provides a formate compound represented by the following general formula (I) which is useful as a sensitizer for a heat-sensitive recording material and is represented by the following chemical formula 2 (same as chemical formula 1). .

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The present invention also provides a sensitizer for a heat-sensitive recording material comprising the above-described formate compound of the present invention.

Hereinafter, the formate compound of the present invention will be described in detail.

The compound of the present invention represented by the above general formula (I) can be obtained, for example, by esterifying 1,4-, 1,3- or 1,2-bis (2-hydroxyethoxy) benzene with formic acid. Can be easily manufactured.

The heat-sensitive recording material to which the compound of the present invention is applied has a support on which a color-forming layer containing a colorless or pale-colored color-forming substance and a color developer which causes the substance to develop color when heated is provided. By incorporating the compound of the present invention represented by the general formula (I) into the color-forming layer, a heat-sensitive recording material having high sensitivity and good storage stability can be obtained.

Various dyes are known as colorless or light-colored coloring substances used in the above-mentioned thermosensitive recording material, and are not particularly limited as long as they are used in general thermosensitive recording papers. .

Specific examples of these dyes include (1) triarylmethane compounds; for example, 3,3-bis (p
-Dimethylaminophenyl) -6-dimethylaminophthalide (commonly known as crystal violet lactone), 3-
(P-dimethylaminophenyl) -3- (1,2-dimethyl-3-indolyl) phthalide, 3- (p-dimethylaminophenyl) -3- (2-phenyl-3-indolyl) phthalide, 3,3- Bis (9-ethyl-3-carbazolyl) -5-dimethylaminophthalide, 3,3-bis
(2) diphenylmethane compounds such as (2-phenyl-3-indolyl) -5-dimethylaminophthalide; for example, 4,4-bis (dimethylamino) benzhydrin benzyl ether, N-2,4,5- (3) Xanthene compounds such as trichlorophenylleuco auramine; for example, rhodamine-β-anilinolactam, 3-dimethylamino-7-methoxyfluoran, 3-dimethylamino-6-methoxyfluoran, 3-dimethylamino -7-
Chlorofluorane, 3-diethylamino-7-methoxyfluoran, 3-diethylamino-6-methyl-7-chlorofluorane, 3-diethylamino-6'7-dimethylfluoran, 3-diethylamino-7-methylaminofluoran 3-diethylamino-7-octylaminofluoran, 3-diethylamino-7- (2-chloroanilino) fluoran, 3-diethylamino-6-chloro-7-γ-chloropropylaminofluoran, 3-diethylamino-6-methyl -7-xylidinofluoran,
3-diethylamino-6-methyl-7-anilinofluoran, 3-diethylamino-6-chloro-7- (β-ethoxyethylamino) fluoran, 3-diethylamino-7- (2-carbomethoxyphenylamino) fluoran, 3-diethylamino-7-diethylaminofluoran, 3-diethylamino-7-dibenzylaminofluoran, 3-diethylamino-7- (N-acetyl-N-
Methylamino) fluoran, 3-diethylamino-7-
(N-methyl-N-chloroethylamino) fluoran,
3-diethylamino-7- (N-methyl-N-benzylamino) fluoran, 3-dibutylamino-6-methyl-7-anilinofluoran, 3-dibutylamino-7-
(2-chloroanilino) fluoran, 3-di-n-amylamino-6-methyl-7-anilinofluoran, 3-
(N-methyl-NN-amylamino) -6-methyl-
7-anilinofluoran, 3- (N-methyl-Nn-
Hexylamino) -6-methyl-7-anilinofluoran, 3- (N-methyl-N-cyclohexylamino)-
6-methyl-7-anilinofluoran, 3- (N-ethyl-N-isopropylamino) -6-methyl-7-anilinofluoran, 3- (N-ethyl-Nn-amylamino) -6 -Methyl-7-anilinofluoran, 3-
(N-ethyl-N-isoamylamino) -6-methyl-
7-anilinofluoran, 3- (N-ethyl-Nn-
Hexylamino) -6-methyl-7-anilinofluoran, 3- (N-ethyl-N-β-ethylhexylamino) -6-methyl-7-anilinofluoran, 3- (N
-Ethyl-p-toluidino) -7-methylfluoran,
3-piperidino-6-methyl-7-anilinofluoran, 3- (N-ethyl-p-toluidino) -6-methyl-7-anilinofluoran, 3- (N-ethyl-p-toluidino)- (4) such as 6-methyl-7- (p-toluidino) fluoran, 3-pyrrolidino-6-methyl-7-anilinofluoran, and 3-pyrrolidino-6-methyl-7-p-butylphenylaminofluoran; (5) Spiro compounds; for example, 3-methylspirodinaphthopyran; thiazine compounds; for example, benzoyl leucomethylene blue and p-nitrobenzoyl leucomethylene blue;
Examples thereof include 3-ethylspirodinaphthopyran, 3-benzylspirodinaphthopyran and 3-methylnaphtho (3-methoxybenzo) spiropyran, and these dyes can be used in combination of several kinds.

Further, as a developer used in the above-mentioned heat-sensitive recording material, a phenol compound, an organic carboxylic acid or a metal salt thereof, or an inorganic acidic substance can be used.

Examples of these developers include p-octylphenol, p-tert-butylphenol, p-phenylphenol, p-hydroxyacetophenone, α
-Naphthol, β-naphthol, p-tert-octyl catechol, 2,2′-dihydroxybiphenyl, bisphenol A, 1,1-bis (p-hydroxyphenyl)
Butane, 2,2-bis (4-hydroxyphenyl) heptane, 2,2-bis (3-methyl-4-hydroxyphenyl) propane, 2,2-bis (3,5-dimethyl-4)
-Hydroxyphenyl) propane, 2,2-bis (3,
5-dichloro-4-hydroxyphenyl) propane, bis (4-hydroxyphenyl) sulfone, bis (3,4
-Dihydroxyphenyl) sulfone, bis (3-allyl-4-hydroxyphenyl) sulfone, 4-hydroxy-4'-isopropoxydiphenyl sulfone, 1,1-
Bis (4-hydroxyphenyl) cyclohexane, bis (4-hydroxyphenyl) ether, p-hydroxybenzoic acid, ethyl p-hydroxybenzoate, butyl p-hydroxybenzoate, benzyl p-hydroxybenzoate, bis (4-hydroxy Phenyl) acetic acid butyl ester, 1,1,3-tris (2-methyl-4-hydroxy-5-tert-butylphenyl) butane, 1,1,3-tris (2-methyl-4-hydroxy-5-cyclohexyl) Phenols such as phenyl) butane, bis [2- (4-hydroxyphenylthio) ethoxy] methane and dimethyl 4-hydroxyphthalate; oxalic acid, maleic acid, tartaric acid, citric acid, succinic acid, stearic acid, and behenic acid Aliphatic carboxylic acids such as benzoic acid, tert-butylbenzoic acid, phthalic acid , Gallic acid, salicylic acid, isopropyl salicylate, phenyl salicylate, 3,5-di-tert-butyl salicylic acid, 3-methyl-5-benzyl salicylic acid, 3,5-di (alpha-methylbenzyl) salicylic acid,
Aromatic carboxylic acids such as 3-phenyl-5- (α, α-dimethylbenzyl) salicylic acid and zinc, magnesium, aluminum, calcium of these carboxylic acids;
Polyvalent metal salts such as titanium, manganese, tin and nickel;
Acid clay, activated clay, attapulgite, bentonite,
Examples thereof include inorganic color developers such as colloidal silica, aluminum silicate, magnesium silicate, zinc silicate, tin silicate, calcined kaolin, and talc.

A heat-sensitive recording material using the bis (hydroxyethoxy) benzene formate compound of the present invention as a sensitizer can be obtained, for example, as follows. The formate ester compound of the present invention is pulverized by a grinding machine such as a ball mill, an attriser, a sand grinder or an appropriate emulsifying device until the average particle size becomes preferably 10 μm or less, more preferably 3 μm or less.

Further, a color-forming substance, a color developer, and other various optional materials to be added as required are atomized by the same apparatus as described above, and these are combined with the atomized compound of the present invention. To make a coating solution.

The coating liquid usually contains polyvinyl alcohol, hydroxyethyl cellulose, methyl cellulose,
Binders such as polyacrylamide polymers, starches, styrene-maleic anhydride copolymers, vinyl acetate-maleic anhydride copolymers, styrene-butadiene copolymers and the like or modified products thereof, silane, kaolin, diatomaceous earth, Fillers such as talc, titanium dioxide, calcium carbonate, magnesium carbonate, aluminum hydroxide, and melamine are blended.

Further, in addition to the above, the coating liquid may contain a metal soap, a wax, a light stabilizer, a waterproofing agent, a dispersant, an antifoaming agent, and the like.

By coating this coating solution on a support such as paper and various films, a desired heat-sensitive recording material can be obtained.

The amount of the bis (hydroxyethoxy) benzene formate compound of the present invention to be added depends on the required performance and recording suitability, or the type and amount of other additives such as a color-forming substance and a developer used. Is also different
Although it cannot be said unconditionally, it is usually preferable to use 0.05 to 10 parts by weight with respect to 1 part by weight of the coloring substance.

[0024]

The present invention will be described in more detail with reference to the following examples. However, the present invention is not limited by the following examples.

Example 1 Synthesis of 1,4-bis (2-formyloxyethoxy) benzene (compound of the following formula 3)

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7.7 g of 99% formic acid and 16.2 g of acetic anhydride were dissolved in 50 g of toluene and stirred at 50 ° C. for 30 minutes under a nitrogen stream. 15 g of 1,4-bis (2-hydroxyethoxy) benzene was added thereto, and the mixture was stirred under reflux for 3 hours.

After cooling, the precipitated white powder was filtered off, washed with water and dried to obtain 16.5 g of a white powder having a melting point of 95 to 101 ° C.

As a result of infrared spectroscopy, the obtained white powder was found to have an absorption of 2950 cm ^-1 (absorption based on formyl group), 170
0 cm ^-1 (absorption based on carbonyl group) and 1630 cm ^-1
(Absorption based on aromatic nuclei), and it was confirmed to be the target substance.

Example 2 Effect of the compound of the present invention as a sensitizer for a heat-sensitive recording material

20 g of 3-dibutylamino-6-methyl-7-anilinofluoran and 100 g of a 10% aqueous solution of polyvinyl alcohol are sufficiently ground to obtain a dye dispersion (A
Liquid).

20 g of bisphenol A and 100 g of a 10% aqueous solution of polyvinyl alcohol were sufficiently ground to obtain a developer dispersion (solution B).

20 g of 1,4-bis (2-formyloxyethoxy) benzene and 100 g of a 10% aqueous solution of polyvinyl alcohol were sufficiently ground to give a sensitizer dispersion (C-1).
Liquid).

For comparison, 20 g of 1,4-bis (2-acetoxyethoxy) benzene and 100 g of a 10% aqueous solution of polyvinyl alcohol were sufficiently ground to obtain a comparative sensitizer dispersion liquid (C-2 liquid). Was.

Solution A, Solution B, Solution C-1 or Solution C-2, and silica in the form of fine powder were mixed in a weight ratio of 1: 2: 2:
The mixture was mixed at a ratio of 0.5 and sufficiently dispersed to obtain a coating liquid.

This coating solution was applied to a base paper of 50 g / m ² with a thickness of 3
It was applied at 2 μm and dried to prepare a heat-sensitive recording material.

Using the obtained heat-sensitive recording material, the color density of a recorded image printed by changing the pulse width using a heat-sensitive printing apparatus (TH-PMD: manufactured by Okura Electric Co., Ltd.), and the printed heat-sensitive recording material to 60 The densities of the recorded images were measured by a Macbeth densitometer (model RD-933, manufactured by Macbeth) for each of the samples stored for 3 hours under the drying conditions at 40 ° C and the atmosphere at 40 ° C and a relative humidity of 90%. The results are shown in Table 1 below.
Shown in

[0037]

[Table 1]

As shown in the above examples, when the formate ester compound of bis (2-hydroxyethoxy) benzene of the present invention was used, the color density was higher than when the acetate compound having a similar structure was used. It is clear that not only is the surface color fog large, but also there is little background fogging or coloring at low energy, and further, there is no coloration of the background portion or decoloration of the printed portion during storage. Therefore,
It is clear that the bis (2-hydroxyethoxy) benzene formate compound of the present invention is extremely useful for obtaining a thermosensitive recording material having high sensitivity and good storage stability.

[0039]

The formate compound of the present invention is a novel compound useful as a sensitizer for heat-sensitive recording materials. Further, by using the sensitizer for a thermosensitive recording material of the present invention comprising the formate ester compound of the present invention, a thermosensitive recording material having high sensitivity and good storage stability can be obtained.

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-2-175187 (JP, A) JP-A-63-130550 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C07C 69/08 B41M 5/26 CA (STN) REGISTRY (STN)

Claims (2)

(57) [Claims] A formate compound represented by the following general formula (I): Embedded image 2. A sensitizer for a heat-sensitive recording material comprising the formate compound according to claim 1.