Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41M—PRINTING, DUPLICATING, MARKING, OR COPYING PROCESSES; COLOUR PRINTING
  • B41M5/00—Duplicating or marking methods; Sheet materials for use therein
  • B41M5/26—Thermography ; Marking by high energetic means, e.g. laser otherwise than by burning, and characterised by the material used
  • B41M5/30—Thermography ; Marking by high energetic means, e.g. laser otherwise than by burning, and characterised by the material used using chemical colour formers
  • B41M5/337—Additives; Binders
  • B41M5/3375—Non-macromolecular compounds
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41M—PRINTING, DUPLICATING, MARKING, OR COPYING PROCESSES; COLOUR PRINTING
  • B41M5/00—Duplicating or marking methods; Sheet materials for use therein
  • B41M5/26—Thermography ; Marking by high energetic means, e.g. laser otherwise than by burning, and characterised by the material used
  • B41M5/30—Thermography ; Marking by high energetic means, e.g. laser otherwise than by burning, and characterised by the material used using chemical colour formers
  • B41M5/333—Colour developing components therefor, e.g. acidic compounds
  • B41M5/3333—Non-macromolecular compounds

Definitions

• This invention relates to a thermal sensitive recording sheet which has an excellent image stability.
• a thermal recording sheet can be obtained be obtained by following procedure ;
• a colourless or pale coloured basic leuco dye and a colour developer such as a phenolic compound are separately ground to fine particles, then mixed together and dispersed.
• a coating colour can be obtained.
• the obtained coating colour is coated on a substrate such as paper, synthetic paper, none-woven cloth, film or plastic, thus a thermal sensitive recording sheet is prepared, which develops colour by a momentary chemical reaction caused by heating with a thermal pen, a thermal head, a hot stamp, laser light or the like.
• thermal recording sheets can be applied in a wide variety of fields such as measuring recorders, terminal printers for computers, facsimiles, automatic ticket venders, ATM (Automatic Teller Machine of bank), HT (Handy Terminal), bar code labels or the like.
• a required quality improvement for the thermal sensitive recording sheet are becoming higher.
• thermal sensitive recording materials such as disclosed in Japanese Patent publication 4160/68 or in Japanese Patent publication 14039/70 can be mentioned.
• the responding speed of these conventional thermal sensitive recording materials is slow, a sufficient colour developing density can not be expected when the recording speed is high.
• thermal sensitive recording sheet which uses a newly developed derivative of urea (thiourea) as a colour developer.
• Said thermal sensitive recording sheet can sufficiently be used for a high energy printing, but in a case of lower energy printing or a high speed printing, an enough colour developing density can not be obtained, furthermore, a stability of recorded image against the plasticizer included in polyvinylchloride film is not sufficient. So it is thought to be impossible to put said thermal sensitive recording sheet to a practical use.
• the object of the present invention is to provide a thermal sensitive recording sheet which has an excellent image stability.
• the inventor has conducted intensive studies to develop a thermal sensitive recording sheet which has an excellent image stability, and consequently accomplished the present invention. That is, the above mentioned object can be solved by including a derivative of urea (thiourea) indicated by general formula (I) or (II) in a thermal sensitive colour developing layer as an organic colour developer, and also including 0.01-2 parts of a derivative of diphenylsulfone indicated by general formula (III) based on 1 part of colour developer indicated by general formula (I) or (II) as a stabilizer.
• a derivative of urea (thiourea) indicated by general formula (I) or (II) in a thermal sensitive colour developing layer as an organic colour developer
• 0.01-2 parts of a derivative of diphenylsulfone indicated by general formula (III) based on 1 part of colour developer indicated by general formula (I) or (II) as a stabilizer.
• Y indicates a sulfur or an oxygen atom.
• B indicates a hydrogen atom, an alkyl group of C 1 -C 4 , an alkoxy group of C 1 -C 4 , a hydroxy group or a nitro group
• R 1 " R 2 " and R 3 indicates a hydrogen atom, an alkyl group of C 1 -C 4 , an alkoxy group of C 1 -C 4 , a hydroxy group or a nitro group.
• R 1 " and “R 2 " can be mutually combined and form an aromatic ring.
• Y indicates a sulfur or an oxygen atom.
• a C 1 -C 4 alkyl group is, for example, methyl, ethyl, i-propyl, n-propyl, t-butyl, s-butyl or n-butyl.
• a C 1 -C 4 alkoxy group is, for example, methoxy, ethoxy, i-propoxy, n-propoxy, t-butoxy, s-butoxy or n-butoxy.
• a derivative of urea (thiourea) indicated by general formula (I) or (II) indicates stronger acidity than a phenolic compound which is a well-known colour developer, and performs very strong colour developing ability to a basic leuco dye.
• the ground of said fact is explained as follows. That, is in a molecule of a derivative of urea (thiourea) used in this invention, since two electron extractive groups e.g. a sulfonyl group, a carbonyl group or a thiocarbonyl group exist so as to put one benzene ring between, an electron density surrounding a nitrogen atom is remarkably fallen down and consequently results a strong colour developing ability to a basic leuco dye.
• the molecule of stabilizer indicated by general formula (III) possesses a sulfone group, when it is fused by heat together with the organic colour developer indicated by general formula (I) or (II), it makes an electron density surrounding a nitrogen atom fall down more, and consequently effects to improve the preservable stability of a recording image.
• a stabilizer a derivative of diphenylsulfone indicated by general formula (III) is used.
• the proportion of a stabilizer indicated by general formula (III) is smaller than 0.01 parts based on 1 part of an organic colour developer indicated by general formula (I) and (II)
• the stabilizing effect is not sufficient, and if it is bigger than 2 parts based on 1 part of an organic colour developer the enough stabilizing effect can not be expected. Therefore, the most desirable proportion of the stabilizer is 0.01-2 parts based on 1 part of the organic colour developer.
• triphnylmethane type As the basic leuco dye used in this invention, triphnylmethane type, fluorane type, fluorene type and divinyl type are desirably used, however, it is not intended to be limited to them. The substantial examples of them are indicated below. These dyes can be used alone or by mixing with others.
• the conventional public known sensitizer can be used as far as it does not hurt the necessary effects of this invention.
• the substantial example of the sensitizer following compounds can be mentioned :
• sensitizers can be used alone or by mixing with others.
• full saponificated polyvinylalcohol having 200-1900 polymerization degree partially saponificated polyvinylalcohol, denatured polyvinylalcohol such as carboxy denatured polyvinylalcohol, amide denatured polyvinylalcohol, sulfonic acid denatured polyvinylalcohol and buthylal denatured polyvinylalcohol, hydroxyethyl cellulose, methyl cellulose, carboxymethyl cellulose, copolymer of styrene-maleic anhydryde, copolymer of styrene-buthadien, derivatives of cellulose such as ethyl-cellulose or acetyl-cellulose, polyvinylchrolide, polyvinylacetate, polyacrylicamide, polyacrilate, polyvinylbuthylal, polystyrene and copolymer of these polymers, polyamide resin, silicon resin, petroleum resin
• macromolecule compound can be used by dissolving in water or in solvents such as alcohol, ketone, ester of hydrocarbon, and also can be used by dispersing it by emulsion or paste state in water or other solvent. These methods can be used in combination with, if necessary.
• filler to be used in this invention following inorganic or organic filler such as silica, calcium carbonate, kaoline, calcined kaoline, diatomaceous earth, talk, titanium oxide, aluminium hydroxide, urea-formalin resin or hollow plastic pigment can be mentioned.
• inorganic or organic filler such as silica, calcium carbonate, kaoline, calcined kaoline, diatomaceous earth, talk, titanium oxide, aluminium hydroxide, urea-formalin resin or hollow plastic pigment can be mentioned.
• parting agents such as metallic salt of fatty acid, lubricant such as wax, ultra violet lay absorder such as benzophenone group or triazole group, waterproof agent such as glyoxal, dispersing agents and deformer can be used in this invention.
• the thermal sensitive recording sheet of this invention can be obtained by following procedure, that is ; prepare the coating colour of thermal sensitive colour developing layer by grinding and dispersing a basic leuco dye, a derivative of urea (thiourea) indicated by aforementioned general formula (I) or (II) as an organic colour developer and a derivative of diphenylsulfone indicated by aforementioned general formula (III) as a stabilizer together with a binder, and adding a filler and other additives according to the necessity, then coating the obtained coating colour on the substrate and drying it up.
• a proportion of a derivative of diphenylsulfone indicated by aforementioned general formula (III) to be added to one part of an organic developer indicated by general formula (I) or (II) is 0.01-2 parts.
• the type and the amount of an organic developer, a basic leuco dye and other additives are decided according to the required features and to the recording property, and generally the preferable amount of these compounds are follows, however, are not intended to be limited. That is, 0.01-2 parts of stabilizer indicated by general formula (III), 0.1-2 parts of basic leuco dye and 0.5-4 parts of filler based on 1 part of organic developer indicated by general formula (I) or (II).
• the preferable amount of binder is 5-25 % to the total amount of solid.
• an objected thermal sensitive recording sheet By coating the coating colour having above mentioned composition on a voluntarily selected supporter such as a paper, a non woven cloth, a film or a plastic, an objected thermal sensitive recording sheet can be obtained. Further, for the purpose of improve the preservability, an overcoat layer of a macromolecule including a filler can be prepared on the thermal sensitive colour developing layer. And, furthermore, for the purpose to improve both preservability and sensitivity, an undercoat layer including an organic or an inorganic filler can be prepared under the thermo sensitive colour developing layer.
• organic developer, basic leuco dye, sensitizer and other additives to be added as necessary are ground to the fine particles smaller than one micron size level by means of a pulverizer such as a ball mill, an attritor or a sand grinder, or by means of an adequate emulsifying apparatus, and binder and other additives are added in accordance with the necessity, thus the coating colour is prepared.
• a pulverizer such as a ball mill, an attritor or a sand grinder, or by means of an adequate emulsifying apparatus, and binder and other additives are added in accordance with the necessity, thus the coating colour is prepared.
• Solution A (dispersion of dye) 3-N-n-dibuthylamino-6-methyl-7-anilinofluoran 2.0 parts 10% polyvinylalcohol aqueous solution 4.6 parts water 2.5 parts
• Solution B (dispersion of colour developer) colour developer (refer to table 1 and 2) 6.0 parts 10% polyvinylalcohol aqueous solution 18.8 parts water 11.2 parts
• Solution C (dispersion of stabilizer) stabilizer 4-benziloxy-4'-(2,3-epoxy-2-methylpropoxy) diphenyl sulfone 4.0 parts 10% polyvinylalcohol aqueous solution 12.5 parts water 7.5 parts
• the prepared coating colours are applied to one side of 50g/m 2 sheet paper so as obtain a coating weight of 5.0g /m 2 amount, dried up and the sheet is processed by a super calender to surface smoothness of 400-500 second.
• the thermal sensitive recording paper can be obtained.
• Solution A (dispersion of dye) 3-N-n-dibuthylamino-6-methyl-7-anilinofluoran 2.0 parts 10% polyvinylalcohol aqueous solution 4.6 parts water 2.5 parts
• Solution D (dispersion of colour developer) colour developer (refer to table 5) 6.0 parts 10% polyvinylalcohol aqueous solution 18.8 parts water 11.2 parts
• the prepared coating colours are applied to one side of 50g/m 2 sheet paper so as obtain a coating weight of 5.0g /m 2 amount, dried up and the sheet is processed by a super calender to surface smoothness of 400-500 second.
• the thermal sensitive recording paper can be obtained.
• Solution A (dispersion of dye) 3-N-n-dibuthylamino-6-methyl-7-anilinofluoran 2.0 parts 10% polyvinylalcohol aqueous solution 4.6 parts water 2.5 parts
• Solution E (dispersion of colour developer) colour developer (refer to table 5) 6.0 parts 10% polyvinylalcohol aqueous solution 18.8 parts water 11.2 parts
• Solution C (dispersion of stabilizer) stabilizer 4-benziloxy-4'-(2,3-epoxy-2-methylpropoxy) diphenyl sulfone 4.0 parts 10% polyvinylalcohol aqueous solution 12.5 parts water 7.5 parts
• the prepared coating colours are applied to one side of 50g/m 2 sheet paper so as obtain a coating weight of 5.0g /m 2 amount, dried up and the sheet is processed by a super calender to surface smoothness of 400-500 second.
• the thermal sensitive recording paper can be obtained.
• Remark (1) resistance against plasticizer are carried out using TH-PMD (thermal sensitive recording paper testing apparatus, to which thermal head [Kyosera Ltd.] is installed) made by Ohkura Denki Ltd., by 0.38mj/dot impressive energy. Image density of the recorded portion of each specimen is measured by a Macbeth densitometer (RD-914, an amber filter is used), and the obtained results are regarded as the image density of untreated specimen.
• TH-PMD thermal sensitive recording paper testing apparatus, to which thermal head [Kyosera Ltd.] is installed
• Image density of the recorded portion of each specimen is measured by a Macbeth densitometer (RD-914, an amber filter is used), and the obtained results are regarded as the image density of untreated specimen.
• N-(benzenesulfonyl)- p -(phenylthioureylene)benzamide none 34 N-(4-toluenesulfonyl)- p -phenylthioureylene)benzamide none 35 N-(benzenesulfonyl)- p -(phenylureylene)benzamide none 36 N-(4-toluenesulfonyl)- p -phenylthioureylene)benzamide none 37 N-(4-methoxyphenylsulfonyl)- p -(phenylureylene)benzamide none Com.

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• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• General Chemical & Material Sciences (AREA)
• Physics & Mathematics (AREA)
• Optics & Photonics (AREA)
• Heat Sensitive Colour Forming Recording (AREA)

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Citations (5)

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• 1996
  • 1996-02-06 JP JP02031296A patent/JP3160885B2/ja not_active Expired - Fee Related
• 1997
  • 1997-01-17 DE DE1997605973 patent/DE69705973T2/de not_active Expired - Fee Related
  • 1997-01-17 EP EP19970300278 patent/EP0788889B1/fr not_active Expired - Lifetime

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