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WÄRMEEMPFINDLICHES AUFZEICHNUNGSMATERIAL - Dokument EP1092553
Dokumentenidentifikation EP1092553 02.11.2006
EP-Veröffentlichungsnummer 0001092553
SUMIKAWA, Naomi, Tokyo 161-0034, JP;
KANEKO, Toshio, Tokyo 161-0034, JP
DE-Aktenzeichen 60030818
EP-Aktenzeichen 009066903
PCT-Aktenzeichen PCT/JP00/01300
WO-Veröffentlichungsnummer 2000053426
IPC-Hauptklasse B41M 5/333(2006.01)A, F, I, 20060306, B, H, EP
IPC-Nebenklasse B41M 5/337(2006.01)A, L, I, 20060306, B, H, EP
The present invention relates to a thermal recording material that has good color developing sensitivity, strong resistance to heat and good ground color.
In general, a thermal recording material having a thermally sensitive color developing layer mainly composed of colorless or pale colored dye precursor and color developing agent that develops color by reacting with said dye precursor when heated is disdosed in Japanese patent publication 45-14039 and widely used on a commercial scale. A thermal printer in which a thermal head is installed is used for the recording with the thermal recording material. Since this kind of thermal recording method is superior to the conventional recording method from the viewpoint of noiselessness in the recording process, does not need developing and fixing processes, is maintenance free, the equipment is relatively cheap and compact and the obtained image is very dear, therefore, this method is widely applied in the field of facsimile or computer, various kinds of measuring instrument and for a labeling machine along with the growth of an information industry. The recording devices attached to these instruments are becoming more diversified and more high-performance, and the required quality to the thermal recording material is becoming more severe. Along with miniaturization of instruments and a requirement for higher recording speeds, it is becoming necessary to obtain deep and clear color developing image.
For the purpose of meeting there requirement, for example, there is disclosed in Japanese Patent Laid open Publication 56-169087, a method of improving the color developing sensitivity by adding a thermo fusion substance to a thermally sensitive layer, and in Japanese Patent Laid Open Publication 56-144193, a method of improving the color developing sensitivity by using a new color developing agent which has high color developing ability. However, these methods cannot be said to have sufficient quality, because these methods have defects such as deterioration of ground colour by heat, powder generation by aging and dropping of colour density after being preserved for long time (reprinting ability). Further, a method of using dye, colour developing agent together with adequate sensitizer can be used. For example, when the colour developing agent is a phenol type compound represented by bisphenol A, p-benzylbiphenyl (Japanese Patent Laid Open Publication 60-82382), p-benzyloxybenzoicbenzy l(Japanese Patent Laid Open Publication 57-201691) or benzylnaphthylether (Japanese Patent Laid Open Publication 58-87094) can be used as an adequate sensitizer. When a sensitizer is used, the sensitizer is fused in the first place and the fused sensitizer dissolves dye and color developing agent which are mixed at the molecular size level so as to cause the colour developing reaction. Therefore, the selection of the kind of sensitizer, dye and colour developing agent is very important.
Dihydroxydiphenylsulfone compound, which is used as an organic colour developing agent is a well-known conventional compound. However, the colour developing ability of it is too poor to meet the current requirement for high sensitivity. As a method of improving the colour developing sensitivity, there is disclosed in Japanese Patent Laid Open Publication 4-69283, a method of adding (p-methylbenzyl)oxalate and in Japanese Patent Laid Open Publication 8-67070, a method of adding solid solution composed of two types of oxalic acid ester derivatives. By these methods, the colour developing sensitivity can be improved more or less. However, from the viewpoints of heat resistance and quality of ground colour, these methods cannot be said to be sufficient. As mentioned above, by use of conventional thermal sensitive recording media, it is difficult to meet the current requirement to improve colour developing sensitivity. Further, it is also difficult to meet the other requirements for quality such as to have good heat resistance and excellent ground colour.
EP-A-0741046 provides a thermally sensitive recording sheet which comprises, on a substrate, a thermally sensitive colour developing layer comprising:
a) a colourless or pale coloured basic achromatic dye;
b) an organic colour developer of the formula (I) or (II): wherein R1 is hydroxy, n-propoxy, isopropoxy or n-butoxy; or and
c) 0.08 to 0.8 parts, per 1 part of the organic colour developer, of a stabiliser which comprises one or more compounds of the formula (III):
wherein X is C1-C4 alkyl, C1-C3 alkoxy, hydrogen, nitro, cyano, or a halogen, and m is an integer of 1 to 3.
EP-A-0778157 provides a thermally sensitive recording medium comprising on a substrate, a thermally sensitive colour developing layer comprising a colourless or pale coloured basic leuco dye and an organic colour developer, wherein the thermal colour developing layer includes from 0.01 to 0.9 parts by weight, based on 1 part by weight of colour developer of one or more compounds of formula (I): wherein X is oxygen or sulphur, R is a group selected from phenyl, naphthyl, aralkyl, C1-C6 alkyl, C3-C6 cycloalkyl and C2-C6 alkenyl, which group is unsubstituted or substituted, Z is C1-C6 alkyl or an electron attracting group, n is 0 or an integer from 1 to 4 and p is an integer from 1 to 5, provided that n+p≤5; and
R1-CONHCH2OH
wherein R1 is C11-C21 alkyl.
JP 08 156415 provides a thermal recording sheet comprising a diphenol sulfone coupler and an aminobenzenesulfonamide stabilizer.
JP 08 142523 provides a thermal recording sheet comprising a sulfone type phenol coupler and an aminobenzenesulfonamide derivative as a stabilizer.
JP 08 142524 provides a thermal recording sheet having a sulfone type phenol coupler and an aminobenzenesulfonamide stabilizer.
EP-A-999072, available for consideration under Article 54(3) EPC, provides a thermally sensitive recording medium which comprises, on a substrate, a thermally sensitive recording layer comprising:
(i) a colourless or pale coloured basic leuco dye,
(ii) an organic colour developer which is a diphenylsulfonone bridgeable type compound of formula (I): wherein X and Y, which are the same or different, are each a saturated or an unsaturated linear or grafted C1-C12 hydrocarbon group which can possess an ether bond, or is of formula (a) or (b): or wherein R is a methylene or ethylene group and T is hydrogen or C1-C4 alkyl, each of the coefficients m, which are the same or different, is 0 or an integer of 1 to 4;
R1, each of which is the same or different when m is 2 or more, is a halogen, C1-C6 alkyl or alkenyl,
R2 to R6, which are the same or different, are each as defined above for R1, and a is 0 or an integer or 1-10, and
(iii) a compound of formula (2):
wherein u is 0 or an integer of 1-2; and R7 which are the same or different when us is 2, is C1 to C6 alkyl or an electron attracting group.
The object of the present invention is to provide a thermal recording material which has good colour developing sensitivity, strong heat resistance of ground colour and excellent ground.
The inventors of this invention have conducted an intensive study and have found that in a thermal recording material which possesses a thermally sensitive colour developing layer containing colourless or pale coloured basic colourless dye and an organic colour developing agent as main components, the thermal recording material which comprises at least one kind of dihydroxydiphenylsulfone type compound of formula (1) and comprising at least one kind of sulfonamide compound represented by formula (2) can solve the above mentioned problems. Further, in this invention, more excellent colour developing sensitivity can be obtained by including 1,2-bis(phenoxymethyl)benzene. wherein R1 and R2 are each independently a C1-8 alkyl group or a C1-8 alkenyl group, or a halogen atom and a and b are each integers of from 0 to 3; wherein either R3 is C1-6 alkyl group or halogen and n is an integer of from 0 to 2, or R3 is methoxy or ethoxy and n is 1.
The sulfonamide compound (2) is present in an amount of from 0.5 to 1.4 parts by weight to 1 part by weight of the compound of formula (1).
In general, the velocity of dissolution and diffusion or solubility of the dye into the melted colour developing agent give the important effects to the colour developing sensitivity of the thermal recording material. To improve said effects, the method of adding various kinds of material as a sensitizer is carried out. It is concerned that the addition of sensitizer causes several effects such as decrease in melting point, decrease in activated energy, change of polarity, improvement of solubility of each material, and the speed of fusing, dissolving and dispersing and saturated solubility are improved. Thus the colour developing sensitivity of the thermal recording material can be improved.
In this invention, the reason why is not made clear, but the colour developing sensitivity can be improved without causing a remarkable decrease in melting point by including a dihydroxydiphenylsulfone compound and further including sulfonamide compound. Therefore, although the color developing sensitivity is improved, color developing of the ground color does not occur.
In the meanwhile, 1,2-bis(phenoxymethyl)benzene is well-known as a sensitizer, and it is confirmed that when 1,2-bis(phenoxymethyl)benzene is added besides the dihydroxydiphenylsulfone compound and the sulfonamide compound, the color developing sensitivity can be further improved.
Further, in this invention, when at least one kind of specific compound chosen from 4-benzyloxy-4'-(2,3-epoxy-2-methyl propoxy)diphenylsulfone, epoxy resin and diphenylsulfone, bridgeable type compound are included it is recognized that the image preservative property of the color developed part is improved. The reason why it not made clear, however, the specific compound is bonded with an electro charge transferring complex which is formed by the reaction between the dye and the color developing agent and becomes more stable. wherein X and Y can be the same or different and are each a saturated or an unsaturated linker or a grafted C1-12 hydrocarbon group which can possess an ether bond, or are each or wherein R is a methylene group or an ethylene group, T is a hydrogen atom or C1-4 alkyl group,
R4 to R9 are each independently a halogen atom, a C1-6 alkyl group or a C1-6 alkenyl group,
e, f, g, h, i, and j are each an integer of from 0 to 4 and when they are each greater than 2, R4 to R9 can be different,
and d is an integer of from 0 to 10.
The thermally sensitive recording medium of this invention, for example, can be produced by following method. That is, a dispersion is prepared in which a dye and compounds represented by formulae (1) and (2), 1,2-bis(phenoxymethyl)benzene and a stabilizer as required are dispersed with a binder, then a filler and other necessary additives are added. Thus the coating for a thermally sensitive color developing layer is prepared. The prepared coating is coated on a substrate and dried so as to form a thermal sensitive color developing layer. In this invention, dihydroxydiphenylsulfone compound represented by formula (1) is provided as an organic color developing agent. Specific examples of formula (1) can be mentioned below. However, it is not intend to be limited to these compounds.
4,4'- dihydroxydiphenylsulfone (1-1)
2,4'- dihydroxydiphenylsulfone (1-2)
bis-(3-allyl-4-hydroxyphenyl)sulfone (1-3)
3,3'-dimethyl-4,4'-dihydroxydiphenylsulfone (1-4)
3,3',5,5'-tetramethyl-4,4'- hydroxyphenylsulfone (1-5)
2,2'-bis(4-chlorophenol)sulfone (1-6)
4-hydroxyphenyl-3'-isopropyl-4'-dihydroxydiphenylsulfone (1-7)
bis-(3-ethyl-4-hydroxyphenyl)sulfone (1-8)
2,2'-bis(p-t-butylphenol)sulfone (1-9)
2,2'-bis(p-t-pentylphenol)sulfone (1-10)
2,2-bis(p-t-octylphenol)sulfone (1-11)
of these compounds, compounds (1-1), (1-2) and (1-3) are desirably used, because of good sensitivity, strong heat resistance, and ease of purchase on the market. These color developing agents can be used alone or in combination.
Further, in this invention, sulfonamide compound represented by formula (2) are included. When the quantity of sulfonamide compound to be contained is too small with to respect the dihydroxydiphenylsulfone compound, since mutual solubility of dye, color developing agent and sensitizer is not improved, good color developing sensitivity cannot be obtained, on the contrary, when the quantity of sulfonamide compound to be included is too much, the color density is slightly deteriorated and powder generation can be observed, further adherence of depositions to a thermal head and sticking at recording are observed. In this invention, from 0.5 to 1.4 parts of sulfonamide compound is present to 1 part of dihydroxydiphenylsulfone compound.
In the compound represented by general formula (2), R3 is a group which does not prevent the sensitizing effect, being a C1-C6 alkyl group, a methoxy, an ethoxy or a halogen atom. As specific examples of compounds represented by formula (2), compounds indicated by (2-1) to (2-28) can be mentioned. However, it is not intended to be limited to these specific compounds. Among these compounds, (2-2) and (2-4) are desirably used, because these compounds display good effect when used together with an organic color developing agent represented by formula (1). These compounds can be used alone or in combination.
Further, in this invention, 1,2-bis(phenoxymethyl)benzene can be provided in the thermally sensitive color developing layer. When the quantity of 1,2-bis(phenoxymethyl)benzene is too small, the color developing sensitivity cannot remarkably improved, and when too much, adherence of depositions to a thermal head and sticking at recording are easily caused. In this invention, it is desirable to use from 0.5-1.4 parts of 1,2-bis(phenoxymethyl)benzene to 1 part of dihydroxydiphenylsulfone compound. When the ratio of sulfonamide compound and 1,2-bis(phenoxymethyl)benzene is from 1:3 to 3:1, the color developing sensitivity and the heat resistance are well balanced.
Further, in this invention, 4-benzyloxy-4'-(2,3-epoxy-2-methylpropoxy) diphenylsulfone, epoxy resin and diphenylsulfone bridgeable type compound of formula (3) can be contained. If the amount of these compounds is too small with respect to the dihydroxydiphenylsulfone compound of formula (1), the image stabilizing effect is not sufficient, and if too much, sensitivity and heat resistance are deteriorated. In this invention, it is desirable to use from 0.01 to 0.9 parts of these compounds to 1 part of dihydroxydiphenylsulfone compound. Especially, if the amount exceed 0.17 parts, the image preservative property of a to plasticizer can be improved.
As the epoxy resin, bisphenol A type epoxy resin, phenol novolak type epoxy resin, cresol novolak type epoxy resin and copolymer of glycidylmethacrylate and vinyl monomer can be mentioned. Among these compounds, the copolymer of glycidylmethacrylate and vinyl monomer can be desirably used because of good effects as a stabilizer and excellent heat resistance. Further, the copolymer of glycidylmethacrylate and vinyl monomer whose average molecular weight is from 9000 to 11000, epoxy equivalent is from 300 to 600 and melting point is lower than 110°C is preferred.
The diphenylsulfone bridgeable type compound of formula (3) is described in Japanese Patent Laid Open Publication 10-29969.
In formula (3), specific examples of groups represented by X and Y are mentioned as follows. That is, methylene group, ethylene group, trimethylene group, tetramethylene group, pentamethylene group, hexamethylene group, heptamethylene group, octamethylene group, nonamethylene group, decamethylene group, undecamethylene group, dodecamethylene group, methylmethylene group, dimethylmethylene group, methylethylene group, methyleneethylene-group, ethylethylene group, 1,2-dimethylethylene group, 1-methyltrimethylene group, 1-methyltetramethylene group, 1,3-dimethyltrimethylene group, 1-ethyl-4-methyl-tetramethylene group, vinylene group, propenylene group, 2-butenylene group, ethynylene group, 2-butynylene group, 1-vinylethylene group, ethyleneoxyethylene group, tetramethyleneoxytetramethylene group, ethyleneoxyethyleneoxyethylene group, ethyleneoxymethyleneoxyethylene group, 1,3-dioxane-5, 5-bismethylene group, 1,2-xylyl group, 1,3-xylyl group, 1,4-xylyl group, 2-hydroxytrimethylene group, 2-hydroxy-2-methyltrimethylene group, 2-hydroxy-2-ethyltrimethylene group, 2-hydroxy-2-propyltrimethylene group, 2-hydroxy-2-isopropyltrimethylene group and 2-hydroxy-2-butyltrimethylene group can be mentioned.
The alkyl or alkenyl group of R4 to R9 is a C1-6alkyl group or a C1-6alkenyl group, and as specific examples, methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, sec-butyl group, tert-butyl group, n-pentyl group, isopentyl group, neopentyl group, tert-pentyl group, n-hexyl group, isohexyl group, 1-methylpentyl group, 2-methylpentyl group, vinyl group, allyl group, isopropenyl group, 1-propenyl group, 2-butenyl group, 3-butenyl group, 1,3-butandienyl group and 2-methyl-2-propenyl group can be mentioned.
And as a halogen atom, chloride, bromine, fluorine or iodine can be mentioned.
In this invention, referring to the diphenylsulfone bridgeable type compound of formula (3), several kinds of the compound whose substitution group and/or number of d are different can be used in combination. The mixing ratio is voluntary. As the mixing method, a mixing method of powders, a mixing method in an aqueous dispersion and a method of reacting several kinds of diphenylsulfone bridgeable type compound simultaneously by controlling the reactive condition can be mentioned. However, it is not intended to be limited to them.
When several kinds of diphenylsulfone bridgeable type compound of formula (3) are used in combination, the desirable composition contains more than 2 kinds of compound represented by formula (5) whose d values only are different. The method for preparation of these kinds of compound is not difficult, that is, by changing the reactive ratio of the starting materials, the compounds whose d values are different can be synthesized simultaneously in any desired ratio. wherein X, Y, R4, m and d are as defined above.
As specific examples of compounds represented by formula (3), the following compounds can be mentioned:
4,4'-bis[4-[4-(4-hydroxyphenylsulfonyl)phenoxy]-2-trans-butenyloxy]diphenyl sulfone
4-[4-(4-hydroxyphenylsulfonyl)phenoxy-4-butyloxy]-4'-[4-(4-hydroxyphenyl sulfonyl)phenoxy-3-propyioxy]diphenylsulfone
4-[4-(4-hydroxyphenylsulfonyl)phenoxy-4-butytoxy]-4'-[4-(4-hydroxypheny sulfonyl) phenoxy-2-ethyloxy]diphenylsulfone
4-[4-(4-hydroxypheny)sulfonyl)phenoxy-3-propyloxy]-4'-[4-(4-hydroxyphenyl sulfonyl)phenoxy-2-ethyloxy]diphenylsulfone
4-[4-[4-hydroxyphenylsulfonyl]phenoxy]-2-trans-butenyloxy]-4'-[4-(4-hydroxy phenylsulfonyl)phenoxy-4-butyloxy]diphenylsulfone
4-[4-(4-hydroxyphenylsulfonyl) phenoxy-2-trans-butenyloxy]-4'-[4-(4-hydroxy phenylsulfonyl)phenoxy-3-propyloxy]diphenylsulfone
4,4'-bis[4-(4-hydroxyphenylsulfonyl)phenoxy-2-ethylenoxyethoxy]diphenyl sulfone
4,4'-bis[4-(4-hydroxyphenylsulfonyl)phenyl-14-phenylenebismethyleneoxy] diphenylsulfone,
2,2'-bis[4-[4-[4-(4-hydroxyphenylsulfonyl)phenoxy-2-ethyleneoxyethoxy]phenyl sulfonyl] phenoxy] diethyl ether
a , a '-bis[4-[4-[4-(4-hydroxyphenylsulfonyl)phenyl-1,4-phenylenebismethylene oxy] phenylsulfonyl]phenoxy]-p-xylene
&agr;,&agr;'-bis[4-[4-[4-(4-hydroxyphenylsulfonyl)phenyl-1,3-phenylenebismethylene oxy]phenylsulfonyl]phenoxy]-m-xylene
&agr;,&agr;'-bis[4-[4-[4-(4-hydroxyphenylsulfonyl)phenyl-1,2-phenylenebismethylene oxy]phenylsulfonyl]phenoxy]-O-xylene
2,4'-bis[2-(4-hydroxyphenylsulfonyl)phenoxy-2-ethyleneoxyethoxy]diphenyl sulfone
2,4'-bis[4-(2-hydroxyphenylsulfonyl)phenoxy-2-ethyleneoxyethoxy]diphenyl sulfone
4,4'-bis[3,5-dimethyl-4-(3,5-dimethyl-4-hydroxyphenylsulfonyl)phenoxy-2-ethyleneoxyethoxy]diphenylsulfone
4,4'-bis[3-allyl-4-(3-allyl-44-hydroxyphenylsulfonyl)phenoxy-2-ethylene oxyethoxy]diphenylsulfone
4,4'-bis[3,5-dimethyl-4-(3,5-dimethyl-4-hydroxyphenylsulfonyl)phenyl-1,4-phenylenebismethyleneoxy]diphenylsulfone
4,4'-bis[3,5-dimethyl-4-(3,5-dimethyl-4-hydroxyphenylsulfonyl)phenyl-1,3-phenylenebismethyleneoxy]diphenylsulfone
4,4'-bis[3,5-dimethyl-4-(3,5-dimethyl-4-hydroxyphenylsulfonyl)phenyl-1,2, phenylenebismethyleneoxy]diphenylsulfone
4,4'-bis[3-allyl-4-(3-allyl-4-hydroxyphenylsulfonyl)1,4-phenylene bismethyleneoxy]diphenylsulfone
4,4'-bis[3-allyl-4-(3-allyl-4-hydroxyphenylsulfonyl)1,3-phenylenebismethylene oxy]diphenylsulfone
4,4'-bis[3-allyl-4-(3-allyl-4-hydroxyphenylsulfonyl) 1,2-phenylenebismethylene oxy]diphenylsulfone
4,4'-bis[4-(4-hydroxyphenylsulfonyl)phenoxy-2-hydroxypropyloxy]diphenyl sulfone
Further, among the compounds formula (4), the compounds where d=0 are the compounds disclosed in Japanese Patent Application 7-149713, PCT Laid Open Publication WO93/06074 and WO95/33714. More specifically,
1,3-bis[4-(4-hydroxyp]enylsulfonyl)phenoxy]-2-hydroxypropane,
1,1-bis[4-(4-hydroxyphenylsulfonyl)phenoxy]methane,
1,2-bis[4-(4-hydroxyphenylsulfonyl) phenoxy]ethane,
1,3-bis[4-(4-hydroxyphenylsulfonyl) phenoxy]propane,
1,4-bis[4-(4-hydroxyphenylsulfonyl)phenoxy]butane,
&agr;,&agr;'-bis[4-(4-hydroxyphenylsulfonyl)phenoxy]-p-xylene,
&agr;,&agr;'-bis[4-(4-hydroxyphenylsulfonyl)phenoxy]-m-xylene,
&agr;,&agr;'-bis[4-(4-hydroxyphenylsulfonyl)phenoxy]-o-xylene,
2,2'-bis[4-(4-hydroxyphenylsulfonyl)phenoxy]diethyl ether,
4,4'-bis[4-(4-hydroxyphenylsulfonyl)phenoxy]dibutyl ether,
1,2-bis[4-(4-hydroxyphenylsulfonyl)phenoxy]ethylene and 1,4-bis[4-(4-hydroxyphenylsulfonyl)phenoxy]-2-butene can be mentioned.
The compound of formula (3) can be obtained by the method described in International Patent Laid Open Publication WO97/16420 which reacts 4,4'-dihydroxyphenylsulfone derivatives, or 2,4'-dihydroxyphenylsulfone derivatives under the presence of basic compound. The compound used in this invention comprises one or more kinds of diphenylsulfone bridgeable type compound prepared by the above mentioned method, and the compounds obtained by following synthetic examples are desirably used.
16.0g (0.4 mole) of sodium hydroxide is added to 21.2g of water and dissolved, then 50.0g (0.2mole) of 4,4-dihydroxydiphenylsulfone (BPS) is added. Then, 14.3g (0.10mole) of bis(2-chloroethyl)ether is added at 105°C, reacted for 5 hours at 110 to 115°C. After the reaction is over, 375ml of water is added to the reacted solution, stirred for 1 hour at 90°C. Then cooled down to the room temperature, neutralized by 20% sulfuric acid. The crystallized solid is filtrated, and 39.3g of white crystalline is obtained. The yield to bis(2-chloroethyl)ether is 88%. The obtained component is analyzed by high performance liquid chromatography and identified as follows; As the column, Mightysil RP-18 (product of Kanto Chemical Co., Ltd.) is used, and the moving bed is CH3CN:H2O:1%H3PO4=700:300:5, and UV wave length is 260nm.
d=0 : retention time 1.9 minutes : area % 32.9 d=1 : retention time 2.3 minutes : area % 21.7 d=2 : retention time 2.7 minutes : area % 12.8 d=3 : retention time 3.4 minutes : area % 8.8 d=4 : retention time 4.2 minutes : area % 5.8 d=5 : retention time 5.4 minutes : area % 3.5 d=6 : retention time 7.0 minutes : area % 2.2 d=7 : retention time 9.0 minutes : area % 1.7 d=8 : retention time 11.8 minutes : area % 1.3 d=9 : retention time 15:4 minutes : area % 1.3
The molar ratio of BPS and bis(2-chloroethyl)ether of Synthetic Example 1 is changed to 1.5:1, 2.5:1, 3.0:1, and the following composition can be obtained.
At 1.5:1,
d=0 is 20.8, d=1 is 33.0, d=2 is 14.2, d=3 is 7.9, d=4 is 3.9
At 2.5:1,
d=0 is 49.6, d=1 is 25.9, d=2 is 11.4, d=3 is 5.3, d=4 is 2.4
At 3.0:1,
d=0 is 56.9, d=1 is 24.9, d=2 is 9.6, d=3 is 3.7, d=4 is 1.3
In a mixed solution of 10.0g of 48% of aqueous solution of sodium hydroxide and 155g of N,N'-dimethylacetoamide, 30.0g (0.12 mole) of BPS is added. After the temperature is rained to 80°C and BPS is dissolved, 10.5g (0.06 mole) of &agr;,&agr;'-dichloro-p-xylene dissolved in 15g of xylene is dropped slowly. Then, the mixture is ripened for 2 hours at the same temperature. After ripening, the solution is poured into 900 ml of water and the crystallized solid is filtrated. The obtained crude crystalline is rinsed with methanol, filtrated and dried, and 19.7g of white crystalline is obtained. The crystalline substance is analyzed by high performance liquid chromatography, and the main components are identified as follows.
&agr;,&agr;'-bis[4-(4-hydroxyphenylsulfonyl)phenoxy]-p-xylene 59.1% 4,4'-bis[4-(4-hydroxyphenylsulfonyl)phenyl-1,4-phenylenebismethyleneoxy] diphenylsulfone 23.1%. &agr;,&agr;'-bis[4-[4-[4-(4-hydroxyphenylsulfonyl)phenyl-1,4-phenylenebismethylene oxy]phenylsulfonyl]phenoxy]-p-xylene 11.1%
As the leuco color developing type basic colorless dye used in this invention, all well known dyes in the field of conventional pressure sensitive type or thermally sensitive type recording paper can be used, and triphenyl methane type compounds, fluoran type compounds, fluorene type compounds, or divinyl type compounds are desirably used. However, it is not intended to be limited to them. Typical examplesof colorless or pale colored leuco dye (dye precursor) are mentioned below. Further, these dye precursor can be used alone or in combination.
<Triphenylmethane type leuco dyers>
1,1-bis-[2',2',2",2"-tetrakis-(p-dimethylaminophenyl)-ethenyl]-2-&bgr;-naphthoyl ethane
1,1-bis-[2',2',2",2"-tetrakis-(p-dimethylaminophenyl)-ethenyl]-2,2-diacetylethane bis-[2,2,2',2'-tetrakis-(p-dimethylaminophenyl)-ethenyl]-methylmalonicacid dimethylester.
Among these compounds, especially, 3-di-n-pentylamino-6-methyl-7-anilinofluoran is desirably used because whiteness of ground color and heat resistance are good.
In this invention, it is concerned that the whiteness of ground color is good, because by providing a specific compound as dye, coloring of the coating can be avoided. In general, it is concerned that the coloring of the coating is caused as follows. Namely, a part of the materials contained in the coating is dissolved in water, and it reacts with dye. For example, 4-4'-dihydroxy diphenylsulfone contains two -OH groups by which a basic colorless dye is color developed, and is easily dissolved in water. The inventors of this invention have conducted intensive study, and have clarified that the coloring of the coating can be peculiarly prevented by combining 3-di-n-pentylamino-6-methyl-7-anilinofluoran as a dye. The reason why is still unclear, however, since the degree of solubility to water of 3-di-n-pentylamino-6-methyl-7-anilinofluoran is lower than 1.349 × 10-6 g/l, which is recognized as a very low level, and the coloring of the coating is very low, therefore the whiteness of the ground color is maintained to high level.
In the present invention, the well known conventional sensitzers can be used within the limitation not to prevent the desirable effect to said object. As specific examples,
fatty acid amide such as stearic add amide and palmitic acid amide, ethylenebisamide,
&bgr; -benzyloxynaphthalene,
di(p-chloro benzyl) oxalate,
di(p-methyl benzyl) oxalate,
1,4-diethoxy naphthalene,
phenyl 1-hydroxy-2-naphthoate and
can be mentioned, However, it is not intended to be restricted to them. These sensitizers can be used alone or in combination.
As the binder to be used in the present invention, fully saponified polyvinyl alcohol of from 200 to 1900 polymerization degree, partially saponified polyvinyl alcohol, denatured polyvinyl alcohol by carboxyl, denatured polyvinyl alcohol by amide denatured polyvinyl alcohol by sulfonic acid denatured polyvinyl alcohol by butylal modified polyvinyl alcohol, derivatives of cellulose such as hydroxyethyl cellulose, methyl cellulose, ethyl cellulose, carboxymethyl cellulose and acetyl cellulose, copolymer of styrene-maleic anhydride, copolymer of styrene-butadiene, polyvinyl chloride, polyvinyl acetal, polyacrylamide, polyacrylic acid ester, polyvinylbutylal, polystyrene or copolymers of them, polyamide resin, silicon resin, petroleum resin, terpene resin, ketone resin and cumarone resin can be illustrated. These macromolecular compounds can be applied by being dissolved into solvents such as water, alcohol, ketone, ester or hydrocarbon or by being dispersed in water or other medium under an emulsion state or a paste state and these forms of application can be used in combination according to the quality requirement.
In this invention, as the image stabilizer showing oil resistance effect of recorded image,
2,2'-di-t-butyl-5,5'-dimethyl-4,4'-sulphonyldiphenol,
1,1,3-tris(2-methyl-4-hydroxy-5-cyclohexylphenyl)butane and
can be added in the limit not to prevent above mentioned desired effect.
As a filler which can be used in this invention, an inorganic or an organic filler such as silica, calcium carbonate, kaoline, calcined kaoline, diatomaceous earth, talc, titanium oxide or aluminum hydroxide can be mentioned. Further, a slipping agent such as waxes, an ultra violet ray absorbing agent such as benzophenone type or triasol type compound, a water proof agent such as glioxasal, a dispersing agent, a defoamer, an anti oxidation agent and fluorescene dye can be used.
The amount of color developer and dye precursor, the kind and amount of other additives to be used in the thermal recording material of this invention are decided according to the required quality and recording features, and not restricted. However, in general, it is preferable to use from 0.1 to 2 parts of basic colorless dye, from 0.01 to 2 parts and from 0.5 to 4 parts of filler to 1 part of color developing agent indicated by formula (1). The desirable amount of binder is from 5 to 25 % to the total amount of solid.
The coating of the above mentioned components is coated over the surface of a substrate such as paper, recycled paper, synthetic paper, film, plastic film, plastic foam film, non-woven cloth or gold foil, and the desired thermal recording material can be obtained. The complex sheet composed of the above mentioned materials can also be used.
Further, to improve the preservative property, an overcoat layer can be prepared on the thermally sensitive color developing layer. Said organic color developer, basic colorless dye and other additives which are added as required are ground to fine particles smaller than several microns diameter by means of a pulverizer such as a ball mill, an attriter or a sand grinder, or by means of an adequate emulsifying apparatus, then the binder and other additives are added as required, thus the coating is prepared. The method of coating is not restricted, and can be coated by conventional well known methods, for example, an off machine coating machine with various coaters such as air knife coater, rod blade coater, bill blade coater or roll coater; or an on machine coating machine can preferably be used.
The thermal recording material of this invention will be illustrated more specifically by Examples. However, it is not intended to be limited to them. In the Examples and Comparative Examples, the term "parts" indicates weight part.
According to the following recipe, dispersions of dye, color developing agent and sensitizer are separately ground in wet conditions to an average particle diameter of 1 µm by a sand grinder.
4,4'- dihydroxydiphenylsulfone (1-1) 6.0 parts 10% aqueous solution of polyvinyl alcohol 18.8 parts water 11.2 parts
-di-n-butylamino-6-methyl-7-anilinofluoran (ODB2) 2.0 parts 10% aqueous solution of polyvinyl alcohol 4.6 parts water 2.6 parts
<dispersion of sulfonamide(SA) compound>
(2-4) compound 6.0 parts 10% aqueous solution of polyvinyl alcohol 18.8 parts water 11.2 parts
The compounds mentioned below are mixed and the coating for the thermally sensitive layer is prepared. The obtained coating is coated over the surface of 50g/m2 high grade paper and dried so to provide a coating amount of 6,0g/m2, and the obtained sheet is treated by a super calendar to provide a Beck's smoothness of from 200 to 600 s. and the thermal recording material is obtained.
dispersion of color developing agent 36.0 parts dispersion of dye 9.2 parts dispersion of sulfonamide compound 36.0 parts 50% dispersion of kaolin day 12.0 parts
By the same process as Example 1, except changing the blending ratio of ODB2 in the dispersion of dye to 3-di-n-pentylamino-6-methyl-7-anilinofluoran (commercial name: Black305, product of Yamada Chemical Industries; hereinafter shortened to B305), the thermal recording material is obtained.
By the same process as Example 1, except using (2-2) instead of (2-4) at the preparation of the dispersion of sulfonamide compound, the thermal recording material is obtained.
By the same process as Example 1, except changing the blending ratio of the dispersion of sulfonamide compound as below, the thermal recording material is obtained.
dispersion of color developing agent 36.0 parts dispersion of dye 9.2 parts dispersion of sulfonamide compound 18.0 parts 50% dispersion of kaolin clay 12.0 parts
By the same process as Example 1, except changing the blending ratio of sulfonamide dispersion as mentioned below, the thermal recording material is obtained.
dispersion of color developing agent 36.0 parts dispersion of dye 9.2 parts dispersion of sulfonamide compound 48.0 parts 50% dispersion of kaolin clay 12.0 parts
According to the following recipe, dispersions of the following materials are prepared and are ground in wet conditions to an average particle diameter of 1 µm by a sand grinder.
<dispersion of stabilizer>
4-benzyloxy-4'-(2,3-epoxy-2-methylpropoxy)diphenylsulfone (commercial name : NTZ-95, product of Nihon Soda ; hereinafter shortened to NTZ) 1.0 parts 10% aqueous solution of polyvinyl alcohol 3.1 parts water 1.9 parts
By the same process as Example 2, except adding a dispersion of stabilizer, the thermal recording material of following recipe is obtained.
dispersion of color developing agent 36.0 parts dispersion of dye 9.2 parts dispersion of sulfonamide compound 36.0 parts dispersion of stabilizer 6.0 parts 50% dispersion of kaolin clay 12.0 parts
By the same process as Example 6, except changing the blending ratio of stabilizer dispersion as mentioned below, the thermal recording material is obtained.
dispersion of color developing agent 36.0 parts dispersion of dye 9.2 parts dispersion of sulfonamide compound 36.0 parts dispersion of stabilizer 18.0 parts 50% dispersion of kaolin day 12.0 parts
dispersion of color developing agent 36.0 parts dispersion of dye 9.2 parts dispersion of sulfonamide compound 36.0 parts dispersion of stabilizer 0.6 parts 50% dispersion of kaolin clay 12.0 parts
[Example 9, 10]
By the same process as Example 6, except changing 4-benzyloxy-4'- (2,3-epoxy-2-methylpropoxy)diphenylsulfone in the stabilizer dispersion to a copolymer of glycidylmethacrylate and vinyl polymer (average molecular weight is 1100, epoxy equivalent is 312, melting point is lower than 110°C) (commercial name : NER-064, product of Nagase Kasei, hereinafter shortened to NER) (Example 9), or to the diphenylsulfone type bridgeable compound of Synthetic Example1 (Example 10), the thermally sensitive recording media are obtained.
<dispersion of 1,2-bis(phenoxymethyl)benzene (BFMB)>
1,2-bis(phenoxymethyl) benzene 6.0 parts 10% aqueous solution of polyvinyl alcohol 18.8 parts water 11.2 parts
By the same process as Example 1, except adding a dispersion of 1,2-bis(phenoxymethyl)benzene and changing the blending ratio as mentioned below, the thermal recording material of the following recipe is obtained.
dispersion of color developing agent 36.0 parts dispersion of dye 9.2 parts dispersion of sulfonamide compound 36.0 parts dispersion of 1,2-bis(phenoxymethyl)benzene 36.0 parts 50% dispersion of kaolin clay 12.0 parts
[Example 12, 13]
By the same process as Example 11, except changing ODB2 in dye dispersion to B305 (Example 12) or to 3-(N-ethyl-N-isoamylamino)-6-methyl-7-anilinofluoran (S205) (Example 13), the thermally sensitive recording media are obtained.
By the same process as Example 11, except changing the blending ratio of sulfonamide compound dispersion and 1,2-bis(phenoxymethyl)benzene dispersion as mentioned below, the thermal recording material is obtained.
dispersion of color developing agent 36.0 parts dispersion of dye 9.2 parts dispersion of sulfonamide compound 18.0 parts dispersion of 1,2-bis(phenoxymethyl)benzene 18.0 parts 50% dispersion of kaolin clay 12.0 parts
dispersion of color developing agent 36.0 parts dispersion of dye 9.2 parts dispersion of sulfonamide compound 48.0 parts dispersion of 1,2-bis(phenoxymethyl)benzene 48.0 parts 50% dispersion of kaolin day 12.0 parts
dispersion of color developing agent 36.0 parts dispersion of dye 9.2 parts dispersion of sulfonamide compound 18.0 parts dispersion of 1,2-bis(phenoxymethyl)benzene 48.0 parts 50% dispersion of kaolin day 12.0 parts
dispersion of color developing agent 36.0 parts dispersion of dye 9.2 parts dispersion of sulfonamide compound 48.0 parts dispersion of 1,2-bis(phenoxymethyl)benzene 18.0 parts 50% dispersion of kaolin day 12.0 parts
dispersion of color developing agent 36.0 parts dispersion of dye 9.2 parts dispersion of sulfonamide compound 36.0 parts dispersion of 1,2-bis(phenoxymethyl)benzene 9.0 parts 50% dispersion of kaolin clay 12.0 parts
dispersion of color developing agent 36.0 parts dispersion of dye 9.2 parts dispersion of sulfonamide compound 36.0 parts dispersion of 1,2-bis(phenoxymethyl)benzene 60.0 parts 50% dispersion of kaolin clay 12.0 parts
[Example20]
By the same process as Example 11, except using 2,4'-dihydroxydiphenyl sulfone (1-2) instead of (1-1) compound at the preparation of dispersion of the color developing agent, the thermal recording material is obtained.
By the same process as Example 12, except using the stabilizer dispersion used in Example 6 and changing the blending ratio as mentioned below, the thermal recording material is obtained.
dispersion of color developing agent 36.0 parts dispersion of dye 9.2 parts dispersion of sulfonamide compound 36.0 parts dispersion of 1,2-bis(phenoxymethyl)benzene 36.0 parts dispersion of stabilizer 6.0 parts 50% dispersion of kaolin day 12.0 parts
By the same process as Example 1, except changing (1-1) compound of the color developing agent dispersion to 4,4'-isopropyridendiphenol (BPA), the thermal recording material is obtained.
By the same process as Example 11, except changing (1-1) compound of the color developing agent dispersion to BPA, the thermal recording material is obtained.
By the same process as Comparative Example 2, except changing ODB2 of the dye dispersion to B305, the thermal recording material is obtained.
By the same process as Example 11, except not blending the sulfonamide dispersion, and using the blending ratio, as mentioned below, the thermal recording material is obtained.
dispersion of color developing agent 36.0 parts dispersion of dye 9.2 parts dispersion of 1,2-bis(phenoxymethyl)benzene 36.0 parts 50% dispersion of kaolin clay 12.0 parts
By the same process as Example 1, except blending the dispersion mentioned below instead of the sulfonamide dispersion, the thermal recording material is obtained.
<dispersion of p-benzylbiphenyl>
p-benzylbiphenyl 6.0 parts 10% aqueous solution of polyvinyl alcohol 18.8 parts water 11.2 parts
By the same process as Example 1, except not blending the sulfonamide dispersion, and using the blending ratio as mentioned below, the thermal recording material is obtained.
dispersion of color developing agent 36.0 parts dispersion of dye 9.2 parts 50% dispersion of kaolin clay 12.0 parts
By the same process as Comparative Example 1, except adding the stabilizer dispersion used in Example 6, the thermal recording material is obtained.
Thermal recording is carried out on the prepared thermally sensitive recording media using TH-PMD, which is a product of Ohkura Denki Co., by 0.25 mJ/dot and 0.34 mJ/dot impressive energy the image density of the printed part is measured by means of a Macbeth densitometer (umber filter used)
[degree of whiteness of ground color]
Degree of whiteness of the not color developed portion of the specimen is measured by a Hunter Whiteness, tester (product of Toyo Seiki Seisakusho, blue filter). A bigger value indicates a good result.
The specimen which is not color developed is left in an atmosphere of 60°C for 24 hrs and 70°C for 1 h, and the whiteness of each specimen is measured by a Hunter Whiteness tester (product of Toyo Seiki Seisakusho, blue filter).
A single sheet of polyvinylchloride wrap (HIGHWRAP KMA : Mitsui Toatsu Chemicals Co., Ltd.) was wound round with 1 ply on a paper tube, stuck on a thermal recording medium recorded by TH-PMD, which is a product of Ohkura Denki Co., by 0.34 mJ/dot impressive energy, further wound round with 3 plies of the polyvinylchloride wrap, allowed to stand at 20°C for 24 hours, and the whiteness of the specimen is measured by a Macbeth densitometer.
A specimen, color developed by 0.34 mJ/dot impressive energy using TH-PMD, which is a product of Ohkura Denki Co., is left in an atmosphere of 60°C for 24 hours, and the specimen is measured by a Macbeth densitometer. [resistance to wet heat]
A specimen, color developed by 0.34 mJ/dot impressive energy using TH-PMD, which is a product of Ohkura Denki Co., is left in an atmosphere of 60°C and 90% humidity for 24 hours, and the specimen is measured by a Macbeth densitometer.
The test results are summarized in Tables 1 to 4. In Tables 1 and 2,
SA: indicates sulfonamide,
BFMB: indicates 1,2-bis(phenoxymethyl)benzene,
SA: BFMB indicates blending ratio,
A number in parentheses indicates blending parts to 1 part of color developing agent.
Example color developing agent SA BFMB dye stabilizer SA:BFMB
1 1-1 2-4(1) ODB2 2 1-1 2-4(1) B305 3 1-1 2-2(1) ODB2 4 1-1 2-4(0.5) ODB2 5 1-1 2-4(1.33) ODB2 6 1-1 2-4(1) B305 NTZ(0.17) 7 1-2 2-4(1) B305 NTZ(0.5) 8 1-1 2-4(1) B305 NTZ(0.017) 9 1-1 2-4(1) B305 NER(0.17) 10 1-1 2-4(1) B305 Synthetic Ex.1 (0.17) 11 1-1 2-4(1) (1) ODB2 1:1 12 1-1 2-4(1) (1) B305 1:1 13 1-1 2-4(1) (1) S205 1:1 14 1-1 2-4(0.5) (0.5) ODB2 1:1 15 1-1 2-4(1.33) (1.33) ODB2 1:1 16 1-1 2-4(0.5) (1.33) ODB2 1:2.7 17 1-1 2-4(1.33) (0.5) ODB2 2.7:1 18 1-1 2-4(1) (0.25) ODB2 4:1 19 1-1 2-4(1) (1.67) 0DB2 1:1.7 20 1-2 2-4(1) (1) ODB2 1:1 21 1-1 2-4(1) (1) B305 NTZ(0.17) 1:1
Comp. Example Color developing agent SA BFMB dye Stabilizer SA:BFMB
1 BPA 2-4 (1) 0DB2 2 BPA 2-4.(1) (1) 0DB2 1:1 3 BPA 2-4 (1) (1) B305 1:1 4 1-1 (1) ODB2 5 1-1 p-benzyl biphenyl(1) ODB2 6 -1-1 ODB2 7 BPA 2-4 (1) ODB2 NTZ(0.17)
Example sensitivity degree of white -ness ground color heat resistance resistance of color developed part to 0.25 mJ/dot 0.34 mJ/dot 60°C 24h 70°C 1 h plasticizer heat wet heat
1 0.78 1.30 80% 76% 74% 0.07 0.56 0.25 2 0.78 1.30 82% 82% 78% 0.07 0.56 0.25 3 0.76 1.29 80% 76% 75% 0.07 0.56 0.25 4 0.75 1.28 80% 76% 74% 0.07 0.56 0.25 5 0.80 1.30 80% 76% 74% 0.07 0.56 0.25 6 0.73 1.27 82% 80% 77% 0.25 1.15 0.78 7 0.67 1.25 82% 79% 76% 0.66 1.25 1.15 8 0.77 1.29 82% 81% 77% 0.09 0.83 0.43 9 0.73 1.29 82% 80% 77% 0.17 1.15 0.78 10 0.73 1.28 82% 81% 78% 0.54 1.05 0.59 11 0.90 1.32 80% 76% 74% 0.07 0.56 0.25 12 0.90 1.32 82% 82% 77% 0.07 0.58 0.25 13 1.00 1.34 76% 73% 68% 0.07 0.58 0.29 14 0.85 1.25 80% 76% 74% 0.07 0.55 0.25 15 0.93 1.34 80% 76% 73% 0.07 0.58 0.25 16 0.91 1.32 80% 76% 74% 0.07 0.56 0.25 17 0.88 1.31 80% 76% 74% 0.07 0.56 0.25 18 0.80 1.30 82% 76% 74% 0.07 0.56 0.25 19 0.88 1.31 82% 76% 74% 0.07 0.56 0.25 20 0.72 1.17 80% 76% 75% 0.07 0.58 0.25 21 0.85 1.29 82% 80% 76% 0.34 1.17 0.88
Comp. Example sensitivity degree of white -ness ground color heat resistance resistance of color developed part to 0.25 mJ/dot 0.34 mJ/dot 60°C 24h 70°C 1 h plasticizer heat wet heat
1 0.75 1.28 75% 68% 67% 0.07 0.56 0.25 2 0.91 1.31 69% 60% 55% 0.07 0.56 0.25 3 0.91 1.31 71% 65% 60% 0.07 0.56 0.25 4 0.31 0.82 80% 76% 75% 0.06 0.35 0.16 5 0.92 1.30 79% 79% 70% 0.07 0.56 0.25 6 0.11 0.55 82% 82% 82% 0.06 0.23 0.11 7 0.70 1.25 73% 66% 68% 0.25 1.14 0.77
As is clearly understood from the above mentioned results in Tables 3 and 4, Examples 1 to 21 of this invention containing sulfonamide and 1,2-bis (phenoxymethyl)benzene in the thermally sensitive layer have excellent qualities such as color developing sensitivity, degree of whiteness of ground color and heat resistance; Especially, Examples 11 to 17, 20 and 21, which contain from 0.5 to 1.4 parts of sulfonamide compound and from 0.5 to 1.4 parts of 1,2-bis (phenoxymethyl)benzen to 1 part of color developing agent have excellent color developing sensitivity. Further, Examples 2, 6 to 10,12 and 21 which use B305 as a dye have an excellent degree of whiteness of ground color and heat resistance compared with the products which use other kinds of dyes. Furthermore, Examples 6 to 10 and 21 in which the stabilizer is blended have excellent image preserving ability. In contrast Comparative Examples 1 to 7 have problems in all qualities.
Possibility to be used in an industrial scale
Since the thermal recording material of this invention has excellent color density, ground color, heat resistance, it can be used as a facsimile paper, printing paper, register paper or thermally sensitive paper, and can provide a high quality and reliable thermal recording material.
Wärmeempfindliches Aufzeichnungsmaterial, das ein Substrat mit einer darauf befindlichen wärmeempfindlichen Farbentwicklungsschicht umfasst, die als Hauptkomponenten einen farblosen oder blass gefärbten basischen Farbstoff und ein organisches Farbentwicklungsmittel umfasst, wobei die wärmeempfindliche Aufzeichnungsschicht mindestens eine Verbindung vom Dihydroxydiphenylsulfon-Typ der Formel (1) als organisches Farbentwicklungsmittel und mindestens eine Sulfonamid-Verbindung der Formel (2) umfasst wobei R1 und R2 jeweils unabhängig voneinander eine C1-8-Alkylgruppe, eine C1-8-Alkenylgruppe oder ein Halogenatom bedeuten und a und b jeweils einen Wert von 0 bis 3 haben, wobei entweder R3 eine C1-6-Alkylgruppe oder ein Halogen bedeutet und n einen Wert von 0 bis 2 hat oder R3 Methoxy oder Ethoxy bedeutet und n den Wert 1 hat; wobei die Sulfonamid-Verbindung der Formel (2) in einer Menge von 0,5 bis 1,4 Gewichtsteilen pro 1 Gewichtsteil der Verbindung der Formel (1) vorliegt. Wärmeempfindliches Aufzeichnungsmaterial nach Anspruch 1, wobei die wärmeempfindliche Farbaufzeichnungsschicht ferner 2,2-Bis-(phenoxymethyl)-benzol umfasst. Wärmeempfindliches Aufzeichnungsmaterial nach Anspruch 1 oder 2, wobei es sich beim farblosen oder blass gefärbten basischen Farbstoff um 3-Di-n-pentylamino-6-methyl-7-anilinofluoran handelt. Wärmeempfindliches Aufzeichnungsmaterial nach einem der vorstehenden Ansprüche, ferner umfassend mindestens eine Verbindung, die aus 4-Benzyloxy-4'-(2,3-epoxy-2-methylpropoxy)-diphenylsulfon, einem Epoxyharz und einer verbrückbaren Verbindung vom Diphenylsulfon-Typ der Formel (3) ausgewählt ist wobei X und Y unabhängig voneinander eine gesättigte oder ungesättigte, lineare oder gepfropfte C1-12-Kohlenwasserstoffgruppe, die gegebenenfalls eine Etherbindung aufweist, oder bedeutet, wobei R eine Methylengruppe oder eine Ethylengruppe bedeutet, T ein Wasserstoffatom oder eine C1-4-Alkylgruppe bedeutet und R4 bis R9 jeweils unabhängig voneinander ein Halogenatom, eine C1-6-Alkylgruppe oder eine C1-6-Alkenylgruppe bedeuten,
e, f, g, h, i und j jeweils einen Wert von 0 bis 4 aufweisen
und d einen Wert von 0 bis 10 aufweist,
wobei die Verbindung, die aus Benzyloxy-4'-(2,3-epoxy-2-methylpropoxy)-diphenylsulfon, einem Epoxyharz und einer Verbindung der Formel (3) ausgewählt ist, in einer Menge von 0,01 bis 0,9 Gewichtsteilen pro 1 Gewichtsteil der Verbindung der Formel (1) vorliegt. Wärmeempfindliches Aufzeichnungsmaterial nach einem der vorstehenden Ansprüche, wobei die Verbindung der Formel (1) ausgewählt ist aus 4,4'-Dihydroxydiphenylsulfon,
2-4'-Dihydroxydiphenylsulfon,
3,3'-Dimethyl-4,9'-dihydroxydiphenylsulfon,
4-Hydroxyphenyl-3'-isopropyl-4,4'-dihydroxydiphenylsulfon,
2,2'-Bis-(p-tert.-octylphenol)-sulfon. Wärmeempfindliches Aufzeichnungsmaterial nach Anspruch 5, wobei es sich bei der Verbindung der Formel (1) um 4,4'-Dihydroxydiphenylsulfon handelt. Wärmeemfpindliches Aufzeichnungsmaterial nach einem der Ansprüche 2 bis 6, wobei 1,2-Bis-(phenoxymethyl)-benzol in einer Menge von 0,5 bis 1,4 Gewichtsteilen bezogen auf die Verbindung der Formel (1) vorliegt. Wärmeempfindliches Aufzeichnungsmaterial nach einem der Ansprüche 2 bis 7, wobei die Sulfonamid-Verbindung der Formel (2) und 1,2-Bis-(phenoxymethyl)-benzol in einem Gewichtsverhältnis von 1:3 bis 3:1 vorliegen.
A thermal recording material which comprises a substrate having thereon a thermally sensitive colour developing layer comprising colourless or pale coloured basic dye and an organic colour developing agent as main components wherein said thermally sensitive recording layer comprises at least one dihydroxydiphenylsulfone type compound of formula (1) as an organic colour developing agent and at least one sulfonamide compound of formula (2) wherein, R1 and R2 are each independently a C1-8 alkyl group, a C1-8 alkenyl group, or a halogen atom and a and b are each from 0 to 3, wherein either R3 is a C1-6 alkyl group or halogen and n is from 0 to 2, or wherein R3 is methoxy or ethoxy and n is 1; wherein the sulfonamide compound of formula (2) is present in an amount of from 0.5 to 1.4 parts by weight to 1 part by weight of the compound of formula (1). A thermal recording material according to claim 1, wherein the thermally sensitive colour developing layer further comprises 2,2-bis(phenoxymethyl)benzene. A thermal recording material according to claim 1 or 2, wherein the colourless or pale coloured basic dye is 3-di-n-pentylamino-6-methyl-7-anilinofluoran. A thermal recording material according to any preceding claim, further comprising at least one compound chosen from 4-benzyloxy-4'-(2,3-epoxy-2-methylpropoxy)diphenylsulfone, epoxy resin and a diphenylsulfone bridgeable type compound of formula (3) wherein X and Y are independently a saturated or unsaturated linear or grafted C1-12 hydrocarbon group optionally having an ether bond, or wherein R is a methylene group or an ethylene group, T is a hydrocarbon atom or a C1-4 alkyl group,
and R4 to R9 are each independently a halogen atom, a C1-6 alkyl group, or a C1-6 alkenyl group,
e, f, g, h, i and j are each from 0 to 4,
and d is from 0 to 10,
wherein the compound chosen from benzyloxy 4'-(2,3-epoxy-2-methylpropoxy)diphenyl sulfone, epoxy resin and a compound of formula (3) is present in an amount of from 0.01 to 0.9 parts by weight to 1 part by weight of the compound of formula (1). A thermal recording material according to any preceding claim, wherein the compound of formula (1) is chosen from 4, 4'-dihydroxydiphenylsulfone,
2-4'-dihydroxydiphenylsulfone,
3,3',5,5'-tetramethyl-4,4'-dihydroxyphenylsulfone,
2,2'-bis(4-chlorophenol)sulfone,
4-hydroxyphenyl-3'-isopropyl-4,4'-dihydroxydiphenylsulfone,
2,2'-bis(p-t-butylphenol)sulfone,
2,2'-bis(p-t-pentylphenol)sulfone, and
2,2'-bis(p-t-octylphenol)sulfone. A thermal recording material according to claim 5, wherein the compound of formula (1) is 4,4'-dihydroxydiphenylsulfone. A thermal recording material according to any of claims 2 to 6, wherein 1,2-bis(phenoxymethyl)benzene is present in an amount of from 0.5 to 1.4 parts by weight of the compound of formula (1). A thermal recording material according to any of claims 2 to 7, wherein the sulfonamide compound of formula (2) and 1,2-bis(phenoxymethyl)benzene are present in a weight ratio of from 1:3 to 3:1.
Matériau d'enregistrement thermique comprenant un substrat ayant à sa surface une couche de développement de couleur thermosensible comprenant un colorant basique incolore ou de couleur pâle et un agent organique de développement de couleur en tant que principaux composants, dans lequel ladite couche d'enregistrement thermosensible comprend au moins un composé de type dihydroxydiphénylsulfone de formule (1) en tant qu'agent organique de développement de couleur et au moins un composé sulfonamide de formule (2) dans laquelle R1 et R2 sont chacun indépendamment un groupe alkyle en C1 à C8, un groupe alcényle en C1 à C8 ou un atome d'halogène et a et b valent chacun de 0 à 3, dans laquelle R3 est un groupe alkyle en C1 à C6 ou un halogène et n vaut de 0 à 2, ou dans laquelle R3 est un groupe méthoxy ou éthoxy et n vaut 1 ; dans lequel le composé sulfonamide de formule (2) est présent en une quantité de 0,5 à 1,4 partie en poids pour 1 partie en poids du composé de formule (1). Matériau d'enregistrement thermique selon la revendication 1, dans lequel la couche de développement de couleur thermosensible comprend en outre du 2,2-bis(phénoxyméthyl)benzène. Matériau d'enregistrement thermique selon la revendication 1 ou 2, dans lequel le colorant basique incolore ou de couleur pâle est du 3-di-n-pentylamino-6-méthyl-7-anilinofluorane. Matériau d'enregistrement thermique selon l'une quelconque des revendications précédentes, comprenant en outre au moins un composé choisi parmi la 4-benzyloxy-4'-(2,3-époxy-2-méthylpropoxy)diphénylsulfone, une résine époxy et un composé de type diphénylsulfone pontable de formule (3) dans laquelle X et Y sont indépendamment un groupe hydrocarbure en C1 à C12 saturé ou insaturé, linéaire ou greffé, ayant éventuellement une liaison éther, ou où R est un groupe méthylène ou un groupe éthylène, T est un atome d'hydrocarbure ou un groupe alkyle en C1 à C4,
et R4 à R9 sont chacun indépendamment un atome d'halogène, un groupe alkyle en C1 à C6 ou un groupe alcényle en C1 à C6,
e, f, g, h, i et j valent chacun de 0 à 4,
et d vaut de 0 à 10,
dans lequel le composé choisi parmi la benzyloxy-4'-(2,3-époxy-2-méthylpropoxy)diphénylsulfone, une résine époxy et un composé de formule (3) est présent en une quantité de 0,01 à 0,9 partie en poids pour 1 partie en poids du composé de formule (1). Matériau d'enregistrement thermique selon l'une quelconque des revendications précédentes, dans lequel le composé de formule (1) est choisi parmi la 4,4'-dihydroxydiphénylsulfone,
la 2,4'-dihydroxydiphénylsulfone,
la bis-(3-allyl-4-hydroxyphényl)sulfone,
la 3,3'-diméthyl-4,4'-dihydroxydiphénylsulfone,
la 3,3',5,5'-tétraméthyl-4,4'-dihydroxyphénylsulfone,
la 2,2'-bis(4-chlorophénol)sulfone,
la 4-hydroxyphényl-3'-isopropyl-4,4'-dihydroxydiphénylsulfone,
la bis-(3-éthyl-4-hydroxyphényl)sulfone,
la 2,2'-bis(p-t-butylphénol)sulfone,
la 2,2'-bis (p-t-pentylphénol) sulfone et
la 2,2'-bis (p-t-octylphénol) sulfone. Matériau d'enregistrement thermique selon la revendication 5, dans lequel le composé de formule (1) est la 4,4'-dihydroxydiphénylsulfone. Matériau d'enregistrement thermique selon l'une quelconque des revendications 2 à 6, dans lequel du 1,2-bis(phénoxyméthyl)benzène est présent en une quantité de 0,5 à 1,4 partie en poids du composé de formule (1). Matériau d'enregistrement thermique selon l'une quelconque des revendications 2 à 7, dans lequel le composé sulfonamide de formule (2) et le 1,2-bis(phénoxyméthyl)-benzène sont présents selon un rapport en poids de 1:3 à 3:1.