Organic compounds -- part of the class 532-570 series – Organic compounds – Carboxylic acid esters
Reexamination Certificate
2001-11-28
2004-01-13
Richter, Johann (Department: 1621)
Organic compounds -- part of the class 532-570 series
Organic compounds
Carboxylic acid esters
Reexamination Certificate
active
06677472
ABSTRACT:
BACKGROUND OF THE INVENTION
(1) Field of the Invention
The present invention relates to novel bis(arylsulfonylaminocarbonylaminobenzoate) compounds and to thermosensitive recording materials containing the same for forming colored images upon heating. More particularly, the present invention relates to novel bis(arylsulfonylaminocarbonylaminobenzoate) compounds and thermosensitive recording materials containing the same and having a high whiteness, an excellent colored image-retaining stability, due to which the color-developed images are not erased, and a high recording sensitivity.
The thermosensitive recording materials of the present invention contains the above-mentioned specific compounds as color-developing components, exhibit a high recording sensitivity and a high whiteness, can record thereon colored images having a good storage property over a long time, and have a high environmental resistance such as a high humidity resistance, a high oil resistance and a high plasticizer-resistance. Thus the thermosensitive recording materials of the present invention are usable for image-recording sheets, cash-dispenser sheets, ticket cards, commuting ticket cards, labels, for example, POS labels, cards, for example, prepaid cards, and pass cards.
(2) Description of the Related Art
Generally, a thermosensitive recording material comprises a substrate comprising a paper sheet, a synthetic paper sheet or a plastic film and a thermosensitive colored image-forming layer formed on the substrate and comprising, as principal components, a color-forming component, for example, an electron-donative leuco dye and a color-developing component comprising an organic acid substance, for example, an electron-acceptive phenol compound. The above-mentioned two components react with each other upon heating to form colored images. This type of thermosensitive recording material is disclosed in Japanese Examined Patent Publication No. 43-4,160, No. 45-14,039 and No. 48-27,736, and is employed in practice.
The thermosensitive recording material is compact, cheap and is easy to maintain, and thus is used in a broad range of practical applications, for example, outputs of computers, facsimiles, automatic ticket vending machines, printers for scientific and measurement equipments, printer for CRT medical measurements and the like. However, in the conventional thermosensitive recording materials, in which a thermosensitive colored image-forming layer contains a color-forming dye component, a color-developing component and a binder, the color-forming reaction is reversible and thus it is known that the colored images is erased with the lapse of time. The color-erasure is accelerated when the images are exposed to light, a high humidity atmosphere or a high temperature atmosphere. The color-erasure is further promoted by immersing in water for long period or by contacting with an oil, for example, salad oil, or with a plasticizer, to such an extent that the images cannot be read or noted.
Regarding the thermosensitive colored image-forming layer using a color-forming system containing a dye precursor including, as a principal component, a colorless or light colored lactone cyclic compound, many attempts to control the color-erasing phenomenon have been made. For example, in one attempt, a phenol compound-containing antioxidant is contained in the thermosensitive colored image-forming layer, as disclosed in Japanese Unexamined Patent Publication No. 60-78,782, No. 59-167,292, No. 59-114,096 and No. 59-93,387; in another attempt, a protective layer is formed from a hydrophobic polymer emulsion on the thermosensitive colored image-forming layer, as disclosed in Japanese Unexamined Patent Publication No. 56-146,796; in still another attempt, the thermosensitive colored image-forming layer is coated with an intermediate layer formed from an emulsion of a water-soluble polymeric compound or a hydrophobic polymeric compound, and the intermediate layer is coated by a surface layer formed from a oily lacquer containing, as a resin component, a hydrophobic polymeric compound, as disclosed in Japanese Unexamined Patent Publication No. 58-199,189; in still another attempt, a phenol compound-containing color developing agent is employed in combination with an epoxy compound, as disclosed in Japanese Unexamined Patent Publication No. 62-164,579; and in further another attempt, a metal salt of a specific salicylic acid derivative is employed as a color-developing agent, as disclosed in Japanese Unexamined Patent Publication No. 62-169,681.
It has been found that the anti-oxidative phenol compound contained in the thermosensitive colored image-forming layer does not contribute to improving the oil resistance of the resultant colored images (a retention of the color density of the colored images a fixed time after a salad oil is brought into contact with the colored images) and the plasticizer resistance of the resultant colored images (a retention of the color density of the colored images a fixed time after a plasticizer is brought into contact with the colored images), in comparison with those on the comparative thermosensitive colored image-forming layer containing no anti-oxidative phenol compound.
Also, in the thermosensitive recording material having the protective layer or the surface layer as mentioned above, the erasure of the colored images due to contact with the oil or plasticizer for a short time can be restricted, but the erasure of the colored images due to the contact with the oil or plasticizer over a long period cannot be prevented, and thus the protective layer and the surface layer are not recognized as essential means for solving the above-mentioned problems.
Further, when the phenol compound is employed in combination with the epoxy compound, a time necessary to stabilize the colored images formed by applying a heating procedure imagewise to the resultant thermosensitive colored image-forming layer, is relatively long. Thus when a salad oil or a plasticizer is brought into contact with the colored images immediately after the colored images are formed on the colored image-forming layer, the colored images are erased to a certain extent.
When the metal salt of the specific salicylic acid derivative is used for the thermosensitive recording material, the retention of the colored images can be improved, but a heat resistance test applied to the thermosensitive recording material causes the non-recorded white portions of the recording material to be colored. Also, the specific salicylic acid derivative is disadvantageous in that the chemical structure of the derivative is complicated and thus the derivative is too expensive.
Generally, to enhance the storage stability of the thermosensitive recording material, a specific additive or a special color-forming material must be used, and thus the resultant colored image-forming layer generally exhibits a relatively low thermosensitivity.
Japanese Unexamined Patent Publication No. 62-19,485 discloses specific color-developing compounds having a sulfonylamide group. The resultant thermosensitive recording material exhibits, however, a color-forming performance the same as or lower than that of the conventional thermosensitive recording material containing the conventional color-developing phenol compound. Namely, the specific color-developing compounds failed to provide an excellent color-forming performance.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a thermosensitive recording material having a high whiteness, a satisfactory resistance of non-recorded portions thereof to unwilling color-development in hot environment, an excellent storage stability including high resistances to oils and plasticizers over a long period, and a high thermosensitivity for color-formation, and new color-developing compounds useful for the thermosensitive recording material.
Another object of the present invention is to provide a thermosensitive recording material not only useful for thermosensitive recording traveller's tickets for ticket-vend
Shirai Ayako
Takahashi Yoshiyuki
Arent Fox Kintner Plotkin & Kahn
Oji Paper Co. Ltd.
Richter Johann
Zucker Paul A.
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