JPS63160881A - Thermai recording material - Google Patents

Abstract

PURPOSE:To obtain a thermal recording material having excellent heat response characteristics and high sensitivity, by incorporating a specified compound as a sensitizer, in a thermal recording material comprising a color developer for developing the color of a dye precursor. CONSTITUTION:A sensitizer (formula I) is ordinarily added in an amount of at least 5 wt.% based on a color developer, preferably, 10-400 wt.%, particularly, 20-300 wt.%. In the formula, R is a lower alkyl. If the amount is less than 5 wt.%, a sensitivity-enhancing effect is insufficient, whereas an addition of more than 400 wt.% of the sensitizer may be inadvantageous on an economical basis, and due to the large amount of a heat-fusible substance, produces a diluting effect, so that a sufficient developed color density can not be obtained. A dye precursor may be a triphenylmethane compound, a fluoran compound or the like. The color developer may be an acidic substance generally used for a thermal recording paper, namely, an electron-acceptive compound, particularly, a phenol derivative, an aromatic carboxylic acid derivative or the like.

Description

DETAILED DESCRIPTION OF THE INVENTION (A>Field of application of fi-f-) The present invention relates to a highly sensitive heat-sensitive recording material with excellent thermal responsiveness.

([3) Prior art heat-sensitive recording materials generally have a heat-sensitive recording layer on a support, the main components of which are an electron-donating, usually colorless or light-colored dye precursor and an electron-accepting color developer. It is equipped with a thermal head,
By heating with a thermal pen, laser light, etc., the dye precursor and developer react during rR, and a recorded image (5I) is produced.
It is disclosed in Publication No. 14039 and the like. Such heat-sensitive recording J/Ai;t records with a relatively compact device, and has the advantages of easy maintenance and no noise blindness. It is used in a wide range of fields such as , printers, combinations, terminals, labels, and automatic ticket vending machines such as train tickets. Especially hun.
In Kushimiri, the demand for heat-sensitive methods is increasing rapidly, and the speed is being increased to reduce transmission costs. In response to the increasing speed of facsimiles, there has been a demand for higher sensitivity heat-sensitive recording materials.

The F7/Kushimiri, which has been made faster than ever before, can receive and send an A4 standard document in a few seconds to 20 seconds, so the current flowing through the F7/Kushimiri head is extremely low, less than a few milliseconds.
The thermal energy generated thereby is transmitted to the heat-sensitive recording sheet to cause an image-forming reaction.

In order to perform an image forming reaction using thermal energy transferred in such a short period of time, it is necessary to use a thermal recording material with excellent thermal responsiveness. 1
It is necessary that In order to increase thermal responsiveness, it is necessary to improve the compatibility between the color developer and the dye precursor. A sensitizer is used for this purpose if necessary. When the sensitizer itself melts due to the transferred thermal energy, it dissolves or encapsulates nearby dye precursors and color developers to promote the color reaction, so the thermal responsiveness of the sensitizer increases. Improving the sensitivity of heat-sensitive recording materials is also one way to increase the sensitivity of heat-sensitive recording materials.

As such a method, waxes are described in JP-A-48-19231;
JP-A No. 53-5636 uses nitrogen-containing compounds, carboxylic acid esters, etc. for fragrance; JP-A-Sho 57-6/1593 uses naphthol-inducing ingredients; 1986-64592Q, especially n 1984-18
No. 5187, 121 Showa 5? -191089 Tan, JP-A No. 58-110289 contains 9 bodies of naf l to nano-in,
2483 bow, JP-A-58-12788, and JP-A-58-162379 include benzoic acid] nistyl derivative)
9 bodies, 11 years ago! Publication No. 22193 describes parabenzylhyphinyl as 'I)5Sho6'l-272
In the 180th publication, phenyls were mentioned, and in JP-A-60-565
8 E3 p publication discloses the addition of diphenoxyethanes, and 15-year publication No. 61-242884 discloses the addition of sulnoids.

However, heat-sensitive recording materials prepared using these methods
Sample No. 1 is still unsatisfactory in terms of color vA degree and color development.

(C) Purpose of the Invention The present inventors have investigated various sensitizers with the aim of creating a highly sensitive heat-sensitive recording material with further excellent thermal responsiveness.

(])) Structure of the Invention A heat-sensitive recording sheet containing a color developer which reacts with a normally colorless or light-colored dye precursor upon heating to cause the dye precursor to develop a color. By incorporating the compound, it was possible to obtain a highly sensitive heat-sensitive recording material with excellent heat responsiveness.

Specific examples of the compound represented by the general formula (wherein R represents a lower alkyl group) are shown below.

(Left below) Compound (1) Compound (2) The compound of the above general formula can be easily converted into 1-I by a known method.

The sensitizer according to the present invention is usually added to the color developer in an amount of 5% by weight or more. The preferred amount is 10-400% by weight;
In particular, 20 to 300% by weight is preferred. Addition amount is 5% by weight
The sensitivity improvement effect was not sufficient with -1, and 400 weight ♀%
If more is added, there will be a disadvantage in terms of Ft bay, and since the amount of thermofusible material 71 will increase, a dilution effect will appear,
Sufficient color development cannot be achieved.

The main components used in the heat-sensitive recording material of the present invention are specifically explained below, but are not limited to: (b).

Dye 1 precursors include 1 to rifhenylmethane, fluoran, diphenylmethane, thiazine, and sp[1
Examples include pyran compounds. For example, 3.3-bis(P-dimedylaminophenyl)-〇-dimedylaminophthalide, 3-(4-di1deldiamino-2-ethoxyphenyl)-3-(1-ethyl-2-methylindole- 3-yl)-4-aryphthalide, 3-diethylamino-6-methyl-7-chlorofluorane, 3-diethylamino-7-[]rofluorane, 3-(N-cyclohexylamino)-7-methylfluorane Oran, 3-diethylamino-7-methylfluorane, 3-diethylamine-
6-chloro-7-methylfluorane, 3-diethylamino-7-7nilinoflu Aran, 3-diethylamine-6
-Methyl-7-dibenzylaminofluorane, 3-(N
-ethyl-N-P-1~luidino)-7-anilinofluorane, 3-di°[thyl7minor7- (0-chloroanilino)fluoran series 3-dibdelamino-7-(0-
3-(N-
C Blue N-P-toluidino)-6-methyl-7-anilinorane, 3-(N-methyl-N-Schiff[Ihexylamino)-6-methyl-7-anilinolluorane,
3-Piperidino-6-methyl-7-anilinofluorane, 3-pyrrolidino-6-mebru 7-anilinofluorane, 3-diethylamino-7-(m-1~lifluoromethyl7-anilino)fluoran, 3- (N-ethyl-N-
Isopendelamino)-6-methyl-7-aninoliflu A run, 3-diethylamino-6-methyl-7-(1)
-phenetidine) fluoran, 3-dibutylamino-7
-(0-fluoroanilino)fluorane, and the like.

As a color developer, an acidic substance 71 commonly used in thermal paper is used.
, that is, electron-accepting compounds are used, in particular phenol derivatives, aromatic carboxylic acid derivatives, N, N''-
Examples include diarylthiourea derivatives and polyvalent metal compounds such as zinc.

Particularly preferable color developers include bisphenols, which may be substituted with one of the hydroxyl groups of the above-mentioned phenol derivatives, and are represented by the following structural formula.

Represents 4F3-inclusive type. R1 is a hydroxyl group, lower alkoxy 4; a cy group, hydrogen,
Represents a lower alkyl group or halogen.

R2 and R3 do not represent hydrogen, a lower alkyl group, a lower alkenyl group, or a halogen. R4 and R5 do not represent hydrogen, a lower alkyl group, or a lower alkoxycarbonyl group. R
4 and R5 may be combined to form a ring. ) Specific examples of compounds represented by the structural formula -1- include 2.2-bis(4-hydroxyphenyl)propane, 2.
．． 2-bis(4-hydroxyphenyl)butane, 1.1
-bis(4-human[14:diphenyl)Schiff[lhex“
Phosphorus, 2.2-bis(4-hydroxyphenyl)pentane, 2
．． 2-bis(4-hydroxyphenyl)hexadi, 2.
2-bis(4-hydroxyphenyl)methyl acetate, 2.2-bis(/1-hydroxyphenyl)ethyl acetate, 2.2-bis(4-l hydroxyphenyl)butyl acetate, bis(4-human[]xyphenyl) ) Sulfone, bis(4
-hydroxyphenyl) sulfoxide, bis(4-hydroxyphenyl) sulfide, 4-hydroxy-4'-
Isopropyloxydiphenylsulfone, 4-hydroxy-4-monomethyldiphenylsulfone, 4-hydroxy-4'-chlorodiphenylsulfone, 2.2-bis(3-1-butyl-4-hydroxyphenyl)propane, 2.2- Bis(3-chloro[1-4-hydroxyphenyl)propane, bis(3-allyl-4-hydroxyphenyl)sulfone, bis(3-1-ablu 4-hydroxy-5-methylphenyl) sulfide, 4-hydroxydiphenyl There are sulfones, etc.

Specific examples of other preferred color developers include benzyl 4-hydroxybenzoate, 1,7-bis(4-hydroxyphenylthio)-3<b>
-Diokyrihebutane, N,N-m-bis(3-chlorophenyl)thiA urea, saprocyanate, N,N--bis(3-trifluoro]comethylphenyl)butane, lauryl gallate , stearyl gallate, behenyl gallate, zinc hydroxynaphthoate, lyridyl 7nylide, dimethyl 4-human[14-cyphthalate, zinc and other metal salts of 5-1-methyllyridylic acid, 6-hydro[co4nylide] Dimethyl 2.3-prophthalene dicarboxylate, methyl 4-hydroxybenzoate, 4-hydroxybenzoic acid, benzyl 2.4-dihydroxybenzoate, benzyl 3.4-dihydroxybenzoate, 4-[-butylbenzoic acid 5-chloroD) j-lydylanilide, isopropyl 4-hydroxybenzoate, 4-hydroxybenzoic acid MM2-phenoxyethyl, benzoic acid, novolac type phenolic resin, 2.2-dihydroxyphenyl, 1-nafl-- , 2-naphl--, bis(2-hydroxy-5-chlorophenyl)methane, 1.1-his(2-hydroxy-5-methylphenyl)dodecane, 4-phenylphenol, 4,-t-butylphenol , (blank below) Phenol 1.5-bis(3-hydroxyphenylenedi)pentane, 1.2-bis(3-human[]oxyphenoxy)ethane,
1.2-bis(4-hydroxyphenoxy)ethane, 1
-('2.4-dihydo['xyphenyl)-1-phenylethane, 4-human stearyl r-1xybenzoate, 1.1-bis(4-hydroxyphenyl)-1-phenylethane, 3-( 2-phenoxyethoxy)phenol, 3.4-
Dihydroxy-4'-methyldiphenylsulfone, etc.

As a binder, tenenes, hydroxyethyllerulose, methylcellulose, carboxymebulyl[1-s], gelatin, casein, polyvinyl alcohol, modified polyvinyl alcohol, styrene-maleic anhydride copolymer, ethylene-maleic anhydride-mylene Water-soluble binders such as acid copolymers, styrene-butadiene copolymers,
Examples include latex-based water-soluble binders such as acryloni-1-lylubutadiene copolymer and methyl acrylate-butadiene copolymer.

Ui 11 includes diatom, talc, kaolin,
Examples include calcined kaolin, calcium carbonate, magnesium carbonate, titanium oxide, zinc oxide, silicon oxide, aluminum hydroxide, urea-formalin resin, and the like.

In addition, highly processed fatty acid metal salts such as zinc stearate and calcium stearate, paraffin, oxidized paraffin, polyethylene, oxidized polyethylene, stearic acid amide, castor wax, and p waxes are used to prevent head wear and stickiness. , dispersants such as sodium dioctyl sulfosuccinate, ultraviolet absorbers such as benzophenone type and benzo 1-lyazole type, surfactants, fluorescent dyes, etc.

Paper is mainly used as the support for the heat-sensitive recording material of the present invention, but non-woven fabric, plastic film, synthetic paper, metal foil, etc., or a composite sheet using a combination of these may optionally be used. Wear.

(E) Synthesis Examples and Examples The present invention will be explained in more detail with reference to Synthesis Examples and Examples. However, the present invention is not limited to the following synthesis examples and examples.

Synthesis Example Synthesis of Compound (1) 4.4'-dihydroxydiphenyl°[-thyl 10°1
U was dissolved in 50 rn1 of acetic acid, and 17.5 g of a 36.0% aqueous solution of 36.0% norium hydroxide was added. While stirring the system, 12.3 g of acetic anhydride was added dropwise over 5 minutes.

Thereafter, stirring was continued for 4114 minutes, and then toluene and water were added to separate the mixture. The six layers were washed with an aqueous sodium hydrogen carbonate solution, dried over anhydrous potassium carbonate, and the solvent was distilled off. The residue is treated with a mixed solvent of n-hexadi and benvin to obtain crystals of the target product. This was further recrystallized from a mixed solvent of n-hexilene and bempine to yield 8.8 g of the target product. Yes.

m, p, -111.5 to 113.0°C Example 3- (N-ethyl-N-isopentylamino)-6-
Melt 7-anilite fluorane 209 was dispersed with a 1% polyvinyl alcohol aqueous solution 809 in a ball mill. On the other hand, 50 g of 2,2-bis(4-human[1-1-diphenyl)propane was dispersed in a ball mill with a 1% polyvinyl alcohol aqueous solution, and 50y of compound (1) was mixed with 1% polyvinyl alcohol. It was similarly dispersed together with 200 g of an aqueous solution.

After mixing these three types of dispersions, 4
Add 125g of 0% dispersion, and add 2g of zinc stearate.
40 g of a 5% dispersion and 300 g of a 10% polyvinyl alcohol aqueous solution were added and thoroughly stirred to prepare a coating liquid. , the coating liquid is applied to a base paper with a basis weight of 49 g/rIt, with a solid content of 6 g as liω.
/Trt, dried, and treated with a supercalender to form a heat-sensitive recording material.

Comparative Example 1 A heat-sensitive recording material was prepared in the same manner as in Example except that 50 g of N-hydroxymethylsderic acid amide was used instead of 50 g of compound (1) used in Example.

The heat-sensitive recording materials obtained in Evaluation Examples and Comparative Examples 1 and 2 were subjected to one facsimile machine from Fujitsu (IIFAcOM FAX-).
The optical temperature of the image printed using 621G was measured using Macbeth RD-514.

The results were tabulated.

As shown in Table (F) Effects of the Invention, by using the sensitizer of the present invention, a highly sensitive heat-sensitive recording material with excellent heat responsiveness can be produced.

Claims (1)

[Scope of Claims] A heat-sensitive recording material containing a color developer that reacts with a normally colorless or light-colored dye precursor upon heating to cause the dye precursor to develop color, containing a compound represented by the following general formula. Features of heat-sensitive recording material. General formula▲There are mathematical formulas, chemical formulas, tables, etc.▼ (However, R represents a lower alkyl group.)