JP2526224B2 - Thermal recording material - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a heat-sensitive recording material, and more particularly to a heat-sensitive recording material having excellent coloring properties.

[Prior art]

A general heat-sensitive recording material is a colorless or light-coloring dye such as a leuco dye as a color former on a support such as paper or film, and a phenolic compound (particularly bisphenol A) as a developer for coloring the same when heated. , A coloring system composed of an acidic substance such as an organic acid, a binder, a filler, a sensitivity enhancer,
Lubricant, provided with a thermosensitive coloring layer in which other auxiliaries are dispersed, for example, JP-B-43-4160, JP-B-45-14039,
It was introduced in Japanese Patent Laid-Open No. 48-27736 and is widely put to practical use. This type of heat-sensitive recording sheet obtains a color image by a momentary chemical reaction between a color-developing agent and a color-developing agent during heating (a thermal printer or a Facsimile having a built-in thermal head is used for heating). Therefore, compared to other recording materials, recording can be obtained in a short time with a relatively simple device without performing complicated processing such as development and fixing, there is little noise and environmental pollution, and cost is low. Due to its advantages such as low cost, it is useful for copying books, documents and the like, and is also useful as a recording material for various information and measuring instruments such as electronic calculators, facsimiles, telex and medical measuring instruments.

On the other hand, in recent years, with the development of society, demands for higher speed and higher recording density have been increasing. For this reason, it is strongly desired not only to increase the speed of the recording apparatus itself but also to develop a recording material that can cope with this. The first method is to lower the melting point of the electron-accepting compound as a color developer to a practically acceptable level such as storage stability (for example, 80 to 120 ° C.), and to set the melting onset temperature with the leuco dye. It is to lower and speed up. However, at present, it is difficult to control the melting point of a phenolic compound which is a color developing agent which is widely used in the field of thermal recording materials, and the phenolic compound itself becomes expensive and is not practical. As the second method, for example, JP-A-53-39139, JP-A-53-261
No. 39, JP-A-53-5636, JP-A-53-11036, etc., various waxes in the heat-sensitive coloring layer,
There is a method of adding a heat-melting substance having a low melting point such as a fatty acid amide, an alkylated biphenyl, a substituted biphenylalkane, coumarins, and diphenylamines as a sensitizer (or melting point depressant). However, it is hard to say that the heat-sensitive recording materials produced by these methods are still sufficient in terms of color density, color sensitivity, background whiteness and the like.

〔Purpose〕

An object of the present invention is to provide a heat-sensitive recording material which has sufficient color density and color sensitivity, is suitable for high speed recording, and has high background whiteness.

〔Constitution〕

The heat-sensitive recording material of the present invention is a heat-sensitive recording material utilizing a color-forming reaction between a leuco dye and a color developer, and is characterized in that a diphenylethylene compound represented by the following general formula (I) is used as an auxiliary component.

(In the formula, X and Y represent an alkyl group or an alkoxyl group, and X and Y may be the same or different. M and n
Each independently represents an integer of 0 to 3. The diphenylethylene compound represented by the above general formula (I) used together as an auxiliary component in the present invention can be used as a color developer (electron-accepting compound) and a leuco dye (electron-donating colorless dye) which are widely used. Sometimes it has a high ability to dissolve,
By adjusting the melting point of the diphenylethylene compound used in combination, a heat-sensitive recording material having arbitrary sensitivity can be obtained.

The diphenylethylene compound used in the present invention has a melting point of 40 to 15 from the viewpoint of storage stability and sensitivity as a thermal recording material.
Those at 0 ° C are preferable, and those at 50 to 120 ° C are particularly preferable. Specific examples of the diphenylethylene compound of the present invention are shown below, but the present invention is not limited thereto.

The leuco dye used in the present invention is applied alone or as a mixture of two or more kinds. As such a leuco dye, those applied to this kind of heat-sensitive material are arbitrarily applied, for example, triphenylmethane And leuco compounds of dyes such as fluoran compounds, phenothiazine compounds, auramine compounds, spiropyran compounds and indolinophthalide compounds are preferably used. Specific examples of such leuco dyes include, for example, those shown below.

3,3-bis (p-dimethylaminophenyl) -phthalide, 3,3-bis (p-dimethylaminophenyl) -6-dimethylaminophthalide (also known as crystal violet red lactone), 3,3-bis ( p-dimethylaminophenyl) -6-diethylaminophthalide, 3,3-bis (p-dimethylaminophenyl) -6-chlorophthalide, 3,3-bis (p-dibutylaminophenyl) phthalide, 3-cyclohexylamino- 6-chlorofluorane, 3-dimethylamino-5,7-dimethylfluorane, 3-diethylamino-7-chlorofluorane, 3-diethylamino-7-methylfluorane, 3-diethylamino-7,8-benzfluorane 3-diethylamino-6-methyl-7-chlorofluoran, 3- (Np-tolyl-N-ethylamino) -6-methyl- -Anilinofluorane, 3-pyrrolidino-6-methyl-7-anilinofluorane, 2- {N- (3'-trifluoromethylphenyl) amino} -6-diethylaminofluorane, 2- {3,6 -Bis (diethylamino) -9- (o-chloroanilino) xanthylbenzoic acid lactam}, 3-diethylamino-6-methyl-7- (m-trichloroethylanilino) fluorane, 3-diethylamino-7- (o-chloroanilino) Fluoran, 3-dibutylamino-7- (o-chloroanilino) fluorane, 3-N-methyl-N-isoamylamino-6-methyl-7-anilinofluorane, 3-N-methyl-N-cyclohexylamino-6 -Methyl-7-anilinofluorane, 3-diethylamino-6-methyl-7-anilinofluorane, 3- N, N-diethylamino) -5-methyl-7-
(N, N-dibenzylamino) fluorane, benzoyl leuco methylene blue, 6'-chloro-8'-methoxy-benzoindolino-
Pyrirospirane, 6'-bromo-3'-methoxy-benzoindolino-
Pyrirospirane, 3- (2'-hydroxy-4'-dimethylaminophenyl) -3- (2'-methoxy-5'-chlorophenyl) phthalide, 3- (2'-hydroxy-4'-dimethylaminophenyl)- 3- (2'-methoxy-5'-nitrophenyl) phthalide, 3- (2'-hydroxy-4'-diethylaminophenyl) -3- (2'-methoxy-5'-methicphenyl) phthalide, 3- (2 '-Methoxy-4'-dimethylaminophenyl) -3- (2'-hydroxy-4'-chloro-5'-
Methylphenyl) phthalide, 3-morpholino-7- (N-propyl-trifluoromethylanilino) fluorane, 3-pyrrolidino-7-trifluoromethylanilinofluorane, 3-diethylamino-5-chloro-7- (N -Benzyl-trifluoromethylanilino) fluorane, 3-pyrrolidino-7- (di-p-chlorophenyl) methylaminofluorane, 3-diethylamino-5-chloro-7- (α-phenylethylamino) fluorane, 3 -(N-ethyl-p-toluidino) -7- (α-phenylethylamino) fluorane, 3-diethylamino-7- (o-methoxycarbonylphenylamino) fluorane, 3-diethylamino-5-methyl-7- (α -Phenylethylamino) fluorane, 3-diethylamino-7-piperidi Fluoran, 2-chloro-3-(N-Mechirutoruijino) -7-
(Pn-Butylanilino) fluorane, 3-N-benzyl-N-cyclohexylamino)-
5,6-benzo-7-α-naphthylamino-4′-bromofluorane, 3-diethylamino-6-chloro-7-anilinofluorane, 3-N-ethyl-N- (2-ethoxypropyl) amino -6-Methyl-7-anilinofluorane, 3-N-ethyl-N-tetrahydrofurfurylamino-6-methyl-7-anilinofluorane, 3-diethylamino-6-methyl-7-mesitidino-
4'-5'-benzofluoran and the like.

As the developer used in the present invention, various compounds having an electron accepting property, for example, phenolic compounds, thiophenolic compounds, thiourea derivatives, organic acids and metal salts thereof are preferably applied. Here is an example.

4,4'-isopropylidene bisphenol, 4,4'-isopropylidene bis (o-methylphenol), 4,4'-secondary-butylidene bisphenol 4,4'-isopropylidene bis (2-tert-butylphenol), 4,4'-cyclohexylidene diphenol, 4,4'-isopropylidene bis (2-chlorophenol), 2,2'-methylene bis (4-methyl-6-tert-butylphenol), 2,2'-methylene bis ( 4-ethyl-6-tert-butylphenol), 4,4'-butylidenebis (6-tertbutyl-2methyl) phenol, 4,4'-thiobis (6-tertbutyl-2-methyl) phenol, 4,4 ' -Diphenol sulfone, 4,4'-diphenol fluphoxide, isopropyl P-hydroxybenzoate, benzoic acid P-hydroxybenzoate , Benzyl protocatechuate, stearyl gallate, lauryl gallate, octyl gallate, 1,7-bis (4-hydroxyphenylthio) -3,5-dioxaheptane, 1,5-bis (4-hydroxyphenylthio) ) -3-Oxapentane, 1,3-bis (4-hydroxyphenylthio) -propane, 1,3-bis (4-hydroxyphenylthio) -2-hydroxypropane, N, N'-diphenylthiourea, N , N′-di (m-chlorophenyl) thiourea, salicylanilide, 5-chloro-salicylanilide, salicyl-o-chloroanilide, 2-hydroxy-3-naphthoic acid, 2-hydroxy-1-naphthoic acid, 1- Hydroxy-2-naphthoic acid, metal salts of hydroxynaphthoic acid such as zinc, aluminum and calcium.

In the present invention, in order to bind and support the leuco dye, the developer and the auxiliary component on the support, various conventional binders can be appropriately used, and examples thereof include polyvinyl alcohol, starch and its derivatives, and methoxycellulose. , Cellulose derivatives such as hydroxyethyl cellulose, carboxymethyl cellulose, methyl cellulose, and ethyl cellulose, polyacrylic acid soda, polyvinylpyrrolidone, acrylic acid amide / acrylic acid ester copolymer, acrylic acid amide / acrylic acid ester / methacrylic acid terpolymer, Styrene / maleic anhydride copolymer alkali salt, isobutylene / maleic anhydride copolymer alkali salt, polyacrylamide, sodium alginate,
In addition to water-soluble polymers such as gelatin and casein, polyvinyl acetate, polyurethane, styrene / butadiene copolymer,
Polyacrylic acid, polyacrylate, vinyl chloride / vinyl acetate copolymer, polybutyl methacrylate, ethylene / vinyl acetate copolymer, styrene / butadiene /
Latex such as acrylic copolymer can be used.

In the present invention, the leuco dye, the color developer, and the auxiliary component may be used, if necessary, in combination with an auxiliary additive component commonly used in this type of heat-sensitive recording material, such as a filler. In this case, as the filler, for example, calcium carbonate, silica, zinc oxide, titanium oxide,
Inorganic fine powders such as aluminum hydroxide, zinc hydroxide, barium sulfate, clay, talc, surface-treated calcium and silica, as well as organic systems such as urea-formalin resin, styrene / methacrylic acid copolymer, polystyrene resin The fine powder of

The heat-sensitive recording material of the present invention is produced, for example, by applying a coating solution for forming a heat-sensitive layer containing the above-mentioned components on a suitable support such as paper, synthetic paper, plastic film and the like, followed by drying. In this case, the amounts of the leuco dye, the color developer and the color sensitivity increasing agent are 5 to 40% by weight,
60% by weight, 20 to 60% by weight is suitable.

〔effect〕

The heat-sensitive recording material of the present invention has improved sensitivity,
It is suitable for high-speed recording and has a high degree of background whiteness, which makes it extremely practical.

〔Example〕

Next, the present invention will be described in more detail with reference to examples.
The parts and% shown below are based on weight.

Example 1 [Liquid A] 3- (N-methyl-N-cyclohexylamino-6-methyl-7-anilinofluorane 20 parts 10% aqueous solution of polyvinyl alcohol 20〃water 60 ″ [liquid B] Bisphenol 20 parts 10% aqueous solution of polyvinyl alcohol 20〃 water 60〃 [C liquid] P- (1-phenylvinyl) anisole (Specific examples of compounds
No3 compound) 20 parts Polyvinyl alcohol 10% aqueous solution 20〃 Water 60〃 [liquid D] Calcium carbonate 20 parts Methylcellulose 5% aqueous solution 20〃 water 60〃 Next, liquid A 10 parts, liquid B 30 parts, liquid C 30 parts, 20 parts of D liquid and 10 parts of 20% aqueous solution of isobutylene-maleic anhydride copolymer were mixed to prepare a thermosensitive color forming layer forming liquid, which was used as basis weight.
After coating and drying on 50g / m ² of high quality paper so that the dry adhesion amount becomes 4 to 5g / m ² , a thermosensitive coloring layer is provided, and then the surface of the layer is further adjusted so that its surface smoothness becomes 500 to 600 seconds. A thermosensitive recording material (a) was prepared by calendering.

Example 2 A thermosensitive recording material (b) was prepared in the same manner as in Example 1 except that the following solution [E] was used instead of the solution [C] in Example 1.

[E] liquid (1-phenylvinyl) -2 ', 4', 6'-trimethylbenzene (compound of compound example No. 8) 20 parts 10% aqueous solution of polyvinyl alcohol 20〃water 60〃 Comparative Example 1 Example A heat-sensitive recording material (c) was prepared in the same manner as in Example 1 except that water was used instead of the liquid [C].

Comparative Example 2 A thermosensitive recording material (d) was prepared in the same manner as in Example 1 except that the following liquid [F] was used instead of the liquid [C] in Example 1.

[F] Solution 20 parts of stearic acid amide 5% aqueous solution of methylcellulose 20〃 water 60〃 Thermal recording materials (a) to (d) obtained as described above
With a thermal printing experimental device having a thin film head manufactured by Matsushita Electronic Components Co., Ltd., a head power of 0.45 W / dot, a line recording time of 20 msec /, a scanning line density of 8 × 3.85 dots / mm, a pulse width of 1.6, Printing was performed at 2.0 and 2.4 (msec), and the printing density was measured with a Macbeth densitometer RD-514 (Filter W-106). The results are shown in Table-1.

Next, the heat-sensitive recording materials (a) to (d) were subjected to a storage stability test for 24 hours under a dry condition of 60 ° C., and changes in background density were examined. The results are shown in Table-2.

From the above, the thermosensitive recording material of the present invention has high color developing sensitivity,
It can be seen that it is a heat-sensitive recording material which is suitable for high-speed recording and also has a high degree of background whiteness and is extremely highly practical.

Claims (1)

(57) [Claims] 1. A heat-sensitive recording material utilizing a color-forming reaction between a leuco dye and a color-developing agent thereof, wherein a general formula as an auxiliary component, (In the formula, X and Y represent an alkyl group or an alkoxyl group, and X and Y may be the same or different. M and n
Each independently represents an integer of 0 to 3. ) A thermosensitive recording material characterized by using a diphenylethylene compound represented by