EP0159874B1 - Prevention of spotting in thermal imaging compositions - Google Patents
Prevention of spotting in thermal imaging compositions Download PDFInfo
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- EP0159874B1 EP0159874B1 EP85302573A EP85302573A EP0159874B1 EP 0159874 B1 EP0159874 B1 EP 0159874B1 EP 85302573 A EP85302573 A EP 85302573A EP 85302573 A EP85302573 A EP 85302573A EP 0159874 B1 EP0159874 B1 EP 0159874B1
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- European Patent Office
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- 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
Definitions
- This invention relates to thermally imageable compositions and to stabilizers for these compositions.
- the leuco dyes may initially be relatively colorless, but can return to a colored form when oxidized, e.g., by air under acidic conditions or any other suitable oxidizing agent.
- leuco dyes used in color image forming systems include triarylmethanes, xanthenes, styryl dyes, and azine dyes, such as, for example, phenoxazines, phenothiazines, and phenazines.
- thermally sensitive materials of the type wherein at least one leuco dye is in reactive proximity with an inorganic nitrate salt, whereby imagewise application of heat causes said nitrate salt to oxidize said leuco dye to produce a change in color a problem may arise from premature spotting or backgrounding of the thermally sensitive material during the drying step of the manufacturing process.
- the term “spotting” means oxidation of the leuco dye to a colored dye form in random irregular spots;
- backgrounding means oxidation of the leuco dye to a colored dye form in uniform fashion, resulting in an evenly colored background. Either spotting or backgrounding can destroy the usefulness of a transparency film bearing a thermally imageable composition.
- One method for preventing spotting involves drying of the imageable coating at low temperatures. This method, however, requires long drying times, slow coating speeds, and high costs, and in most cases, does not offer a practical solution to the problem.
- thermally imageable transparency films based upon combinations of leuco dyes and nitrate salts it is essential that the thermally imageable compositions show considerable stability to the thermal effects of the manufacturing process in order to have a useful shelf life.
- US 4,423,139 discloses thermally imageable compositions comprising a leuco dye, an inorganic nitrate salt, a polymeric binder and a stabilising combination comprising a) one or more aromatic compounds which form quinones, diimines or quinonimines upon oxidation and b) phenidone or phenidone derivatives.
- the stabilising combination stabilises the leuco dye of the thermally developable system against oxidation and premature reaction.
- JP-A-5798392 discloses a thermosensitive recording composition
- a thermosensitive recording composition comprising a leuco dye, a nitrate, a microencapsulated base e.g. sodium carbonate, a reducing agent e.g. thiourea and a thermoplastic resin.
- EP-A-124,296 discloses a thermographic imaging system comprising a leuco dye, a nitrate salt, and optionally an acid and a stabilising compound.
- the stablising compound may be the base phenidone or catechol or hydroquinone.
- US-A-3 460 964 discloses a heat-sensitive composition which can be used to prepare heat-sensitive recording elements comprising an aqueous solvent, a metal nitrate, a leuco-dye and optionally a thickener, a stabilizer, a sensitizer or similar agents.
- Certain bases are mentioned as suitable stabilizers such as 2, 2' - (phenylimino) - diethanol (equals N, N bis - (2-hydroxyethyl) - aniline) and amino diethanol.
- the function of the stabilizer is to maintain the heat-sensitive recording elements or sheets in a uniformally active condition for several weeks or more and thereafter for some time still operable at a gradually reduced sensitivity level.
- the present invention provides a thermally imageable composition
- a thermally imageable composition comprising i) at least one leuco dye in reactive proximity to an inorganic nitrate salt, whereby imagewise application of heat causes said nitrate salt to oxidize said at least one leuco dye to produce a change in color, the cation of said nitrate salt being non-reactive with said leuco dye, and ii) at least one base whose conjugate acid has a pKa greater than or equal to zero, said at least one base being a compound in one of the categories: wherein
- R 1 , R 2 , or R 3 is a substituted alkyl or aryl group
- the substituents can be any other than hydroxy or alkylthio which do not deleteriously affect the function of the thermographic system.
- Suitable substituents include halo groups, e.g. chloro, bromo, iodo, fluoro; cyano group; nitro group; alkoxy group having, for example, 1 to 20 carbon atoms; alkyl carbonyl group having, for example, 1 to 20 carbon atoms; alkylsulfonyl group, having, for example, 1 to 20 carbon atoms.
- R 1 , R 2 , R 3 can be mono-, di-, tri-, or tetra- substituted.
- Dye classes which can be stabilized by the bases include styryl, phenoxazine, phenothiazine, and phenazine.
- styryl dyes are (a) 2,3-dihydro-1,3,3-trimethyl-2-[2-(2,4,6-trimethoxyphenyl)ethenyl]-1 H-Indole; (b) 2-bromo-4-[2-(5-chloro-2,3-dihydro-1,3,3-trimethyl-1 H-indol-2-yl)ethenyl]-N,N-dimethylbenzenamine; (c) 2,3-dihydro-1,3,3-trimethyl-2-[2-(4-dimethylamino)-phenyl-ethenyl]-1H-Indole; (d) 2,3-dihydro-1,3,3-trimethyl-2-[2-(4-N-morpholino-)phenyl-ethenyl]-I
- phenoxazine and phenothiazine dyes are: (f) 3,7-bis-(N,N-diethylamino)-10-benzoyl-phenoxazine and (g) 3,7-bis-(N,N-dimethylamino)-10-benzoyl-phenothiazine, respectively.
- phenazine dyes are: (h) 5,10-dihydro-5-phenyl-10-benzoyl-3,7-bin-(N,N-diethylamino)phenazine and (i) 5,10-dihydro-5-ethyl-10-benzoyl-3,7-bis-(N,N-dimethylamino)phenazine.
- Nitrate salts suitable for this invention are themselves well known. They may be supplied as various chemical compounds, but are desirably provided as a metal salt, and most preferably provided as a hydrated metal salt. Most means of supplying the nitrate salt into the imaging composition are satisfactory. For example, organic salts, metal salts, acid salts, mixtures of acids and salts, and other means of supplying the ion are useful. Nitrates of zinc, cadmium, potassium, calcium, zirconyl (Zr0 2 ), nickel, aluminum, chromium, iron, copper, tin, magnesium, lead, and cobalt, ammonium nitrate, and cerous ammonium nitrate can be used.
- the nitrate salt component of the present invention must be present in a form within the imaging composition so that oxidant (i.e., decomposition products of the nitrate) will be provided within the composition when it is heated to a temperature no greater than 200 F (93 C) for 60 seconds and preferably no greater than 160° F (71 ° C) for 60 or most preferably 30 seconds.
- the salt must be chosen so that the cation thereof is non-reactive with the leuco dye.
- non-reactive salts are defined as those salts the cations of which do not spontaneously oxidize the dyes that they are associated with at room temperature.
- Preferred salts are the hydrated metal salts such as nickel nitrate hexahydrate, magnesium nitrate hexahydrate, aluminum nitrate nonahydrate, ferric nitrate nonahydrate, cupric nitrate trihydrate, zinc nitrate hexahydrate, cadmium nitrate tetrahydrate, bismuth nitrate pentahydrate, thorium nitrate tetrahydrate, cobalt nitrate hexahydrate, gadolinium or lanthanum nitrate nonahydrate, and mixtures of these hydrated nitrates.
- Nonhydrated or organic nitrates may be admixed therewith.
- nitrate ion per mole of dye It is preferred to have at least 0.10 mole of nitrate ion per mole of dye. It is more preferred to have at least 0.30 or 0.50 mole of nitrate ion per mole of dye.
- the bases described in this invention can be used at as low a concentration as 0.05 equivalent of base per equivalent of nitrate ion, or as high as 1.0 equivalent of base per equivalent of nitrate ion.
- the preferred range is from about 0.3 to about 0.6 equivalent of base per equivalent of nitrate ion.
- the thermally stimulated oxidation of the leuco dye by the nitrate salt can be facilitated by the presence of an acid.
- the acids optionally useful in the thermographic system of this invention are acids as generally known to the skilled chemist.
- Organic acids, preferably those having carboxylic groups, such as phthalic acid, are preferred, but inorganic acids can also be used.
- the acid can be present in a ratio of from 0 to 10 times the amount of the nitrate ion.
- the binder be selected from polymeric materials.
- Such resins as polyvinyl acetals, e.g., polyvinyl butyral, polyvinyl resins, polyvinylpyrrolidone, polyesters, polycarbonates, polyamides, polyacrylates, cellulose esters, copolymers and blends of these classes of resins, can be used. Saran, a vinyl chloride-vinylidene chloride copolymer, is particularly preferred. Natural polymeric materials such as gelatin and gum arabic can also be used.
- the leuco dye should be present at a concentration of at least 0.3% by weight, based on the weight of the binder, preferably at a concentration of at least 1% by weight, based on the weight of the binder, and most preferably at a concentration of from 2 to 10% or more by weight, based on the weight of the binder.
- a formulation which can be applied by conventional coating techniques can be produced by dissolving the leuco dye, the metal nitrate, and the polymeric binder, together with an organic acid, and, optionally, a conventional stabilizing compound, e.g. catechol, phenidone, along with the base whose conjugate acid has the required pKa in an inert organic solvent, such as, for example, acetone, methyl ethyl ketone, or tetrahydrofuran.
- a conventional stabilizing compound e.g. catechol, phenidone
- the formulation can be coated onto a support by methods well known in the art, such as, for example, wire-wound rod, knife, or extrusion coating.
- Typical wet thickness of the layer can range from about 10 to about 100 micrometers (pm), and the layer can be dried in forced air at temperatures ranging from 20 C to 50 C. It is preferred that the coating thickness be selected to provide maximum image densities greater than 0.2, and more preferably in the range of 0.5 to 1.5, as measured on a MacBeth Color Densitometer Model TD 504 using the color filter complementary to the dye color.
- the support material can be selected from a wide range of materials, including paper, glass, polymeric film, and the like, depending upon the particular imaging requirement.
- Preferred materials include polymers having good heat stability, such as polyesters.
- a particularly preferred polyester is polyethylene terephthalate.
- percentage of spotting is defined here as the ratio of the area of coated film which is colored due to premature oxidation of the leuco dye, divided by the total area of coated film, multiplied by 100. As the pKa of the base's conjugate acid approaches zero, the additive is less effective as an antispotting agent.
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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)
Description
- This invention relates to thermally imageable compositions and to stabilizers for these compositions.
- It is well known that dyes in their reduced leuco form can provide the basis of color image forming systems. The leuco dyes may initially be relatively colorless, but can return to a colored form when oxidized, e.g., by air under acidic conditions or any other suitable oxidizing agent. Examples of leuco dyes used in color image forming systems include triarylmethanes, xanthenes, styryl dyes, and azine dyes, such as, for example, phenoxazines, phenothiazines, and phenazines.
- In thermally sensitive materials of the type wherein at least one leuco dye is in reactive proximity with an inorganic nitrate salt, whereby imagewise application of heat causes said nitrate salt to oxidize said leuco dye to produce a change in color, a problem may arise from premature spotting or backgrounding of the thermally sensitive material during the drying step of the manufacturing process.
- As used herein, the term "spotting" means oxidation of the leuco dye to a colored dye form in random irregular spots; the term "backgrounding" means oxidation of the leuco dye to a colored dye form in uniform fashion, resulting in an evenly colored background. Either spotting or backgrounding can destroy the usefulness of a transparency film bearing a thermally imageable composition. One method for preventing spotting involves drying of the imageable coating at low temperatures. This method, however, requires long drying times, slow coating speeds, and high costs, and in most cases, does not offer a practical solution to the problem.
- In thermally imageable transparency films based upon combinations of leuco dyes and nitrate salts it is essential that the thermally imageable compositions show considerable stability to the thermal effects of the manufacturing process in order to have a useful shelf life.
- US 4,423,139 discloses thermally imageable compositions comprising a leuco dye, an inorganic nitrate salt, a polymeric binder and a stabilising combination comprising a) one or more aromatic compounds which form quinones, diimines or quinonimines upon oxidation and b) phenidone or phenidone derivatives. The stabilising combination stabilises the leuco dye of the thermally developable system against oxidation and premature reaction. Certain bases are disclosed in Example 11 all of which are outside the scope of the claims as filed.
- JP-A-5798392 discloses a thermosensitive recording composition comprising a leuco dye, a nitrate, a microencapsulated base e.g. sodium carbonate, a reducing agent e.g. thiourea and a thermoplastic resin.
- EP-A-124,296 discloses a thermographic imaging system comprising a leuco dye, a nitrate salt, and optionally an acid and a stabilising compound. The stablising compound may be the base phenidone or catechol or hydroquinone.
- US-A-3 460 964 discloses a heat-sensitive composition which can be used to prepare heat-sensitive recording elements comprising an aqueous solvent, a metal nitrate, a leuco-dye and optionally a thickener, a stabilizer, a sensitizer or similar agents. Certain bases are mentioned as suitable stabilizers such as 2, 2' - (phenylimino) - diethanol (equals N, N bis - (2-hydroxyethyl) - aniline) and amino diethanol. The function of the stabilizer is to maintain the heat-sensitive recording elements or sheets in a uniformally active condition for several weeks or more and thereafter for some time still operable at a gradually reduced sensitivity level.
- The present invention provides a thermally imageable composition comprising i) at least one leuco dye in reactive proximity to an inorganic nitrate salt, whereby imagewise application of heat causes said nitrate salt to oxidize said at least one leuco dye to produce a change in color, the cation of said nitrate salt being non-reactive with said leuco dye, and ii) at least one base whose conjugate acid has a pKa greater than or equal to zero, said at least one base being a compound in one of the categories:
- R1, R2, and R3 can be the same or different and represent a member of the group selected from substituted or unsubstituted alkyl groups having 1 to 20 carbon atoms, substituted or unsubstituted alkenyl groups having from 1 to 16 carbon atoms, and substituted or unsubstituted aryl groups having up to 3 fused rings, subject to the proviso that if R1, R2 or R3 is a substituted group, its substitutent is neither hydroxy nor alkylthio;
- R1 is as defined above, and R4 represents CR5R6 where R5 and R6 represents a member of the class from which R1, R2, and R3 are selected, with the proviso that R5 and R6 need not be the same as R1, R2, or R3;
- x is 0, 1, or 2, y is an integer from 0 to 8, inclusive, and z is 0, 1, or 2, and R7 represents a member of the class from which R1, R2, and R3 are selected, with the proviso that R7 need not be the same as R1, R2, R3; or
- R20 and R21 can be the same or different and represent a member of the group selected from substituted or unsubstituted alkyl groups having 1 to 20 carbon atoms and substituted or unsubstituted alkenyl groups having 1 to 16 carbon atoms; subject to the proviso that if R20 and R21 are a substituted group at least one of the substituent is not hydroxy
- R20 represents a member of the group selected from substituted or unsubstituted alkyl groups having 1 to 20 carbon atoms and substituted or unsubstituted alkenyl groups having 1 to 16 carbon atoms.
- R1, R2, and R3 are as defined above, and R8 represents a member of the class from which R1, R2, and R3 are selected, with the proviso that R8 need not be the same as R1, R2, or R3;
- R9, R10, and R11, can be the same or different and represent a member of the group selected from H, -N02, -CN, -COR12, -COOR12, and S02R12 where R12 is selected from the group consisting of phenyl group, naphthyl group, alkyl group having 1 to 4 carbon atoms, and
- A is as defined above;
- A is as defined above, and
- R13 represents the phenyl or naphthyl group;
- Addition of one or more of the above bases results in decrease or elimination of spotting thus allowing an increase in the drying temperature during the drying step of the manufacturing process, further resulting in faster drying higher coating rates decreased moisture sensitivity and lower manufacturing costs.
- When R1, R2, or R3 is a substituted alkyl or aryl group, the substituents can be any other than hydroxy or alkylthio which do not deleteriously affect the function of the thermographic system. Suitable substituents include halo groups, e.g. chloro, bromo, iodo, fluoro; cyano group; nitro group; alkoxy group having, for example, 1 to 20 carbon atoms; alkyl carbonyl group having, for example, 1 to 20 carbon atoms; alkylsulfonyl group, having, for example, 1 to 20 carbon atoms. R1, R2, R3 can be mono-, di-, tri-, or tetra- substituted.
- Dye classes which can be stabilized by the bases include styryl, phenoxazine, phenothiazine, and phenazine. Representative examples of styryl dyes are (a) 2,3-dihydro-1,3,3-trimethyl-2-[2-(2,4,6-trimethoxyphenyl)ethenyl]-1 H-Indole; (b) 2-bromo-4-[2-(5-chloro-2,3-dihydro-1,3,3-trimethyl-1 H-indol-2-yl)ethenyl]-N,N-dimethylbenzenamine; (c) 2,3-dihydro-1,3,3-trimethyl-2-[2-(4-dimethylamino)-phenyl-ethenyl]-1H-Indole; (d) 2,3-dihydro-1,3,3-trimethyl-2-[2-(4-N-morpholino-)phenyl-ethenyl]-IH-Indole; (e) 2,3-dihyoro-1,3,3-trimethyl-2-[2-(4-N,N-bis-(2-cyanoethylamino)-phenyl-ethenyl]-1 H-Indole.
- Nitrate salts suitable for this invention are themselves well known. They may be supplied as various chemical compounds, but are desirably provided as a metal salt, and most preferably provided as a hydrated metal salt. Most means of supplying the nitrate salt into the imaging composition are satisfactory. For example, organic salts, metal salts, acid salts, mixtures of acids and salts, and other means of supplying the ion are useful. Nitrates of zinc, cadmium, potassium, calcium, zirconyl (Zr02), nickel, aluminum, chromium, iron, copper, tin, magnesium, lead, and cobalt, ammonium nitrate, and cerous ammonium nitrate can be used.
- The nitrate salt component of the present invention must be present in a form within the imaging composition so that oxidant (i.e., decomposition products of the nitrate) will be provided within the composition when it is heated to a temperature no greater than 200 F (93 C) for 60 seconds and preferably no greater than 160° F (71 ° C) for 60 or most preferably 30 seconds. The salt must be chosen so that the cation thereof is non-reactive with the leuco dye. In the practice of the present invention, non-reactive salts are defined as those salts the cations of which do not spontaneously oxidize the dyes that they are associated with at room temperature.
- Preferred salts are the hydrated metal salts such as nickel nitrate hexahydrate, magnesium nitrate hexahydrate, aluminum nitrate nonahydrate, ferric nitrate nonahydrate, cupric nitrate trihydrate, zinc nitrate hexahydrate, cadmium nitrate tetrahydrate, bismuth nitrate pentahydrate, thorium nitrate tetrahydrate, cobalt nitrate hexahydrate, gadolinium or lanthanum nitrate nonahydrate, and mixtures of these hydrated nitrates. Nonhydrated or organic nitrates may be admixed therewith.
- It is preferred to have at least 0.10 mole of nitrate ion per mole of dye. It is more preferred to have at least 0.30 or 0.50 mole of nitrate ion per mole of dye.
- The bases described in this invention can be used at as low a concentration as 0.05 equivalent of base per equivalent of nitrate ion, or as high as 1.0 equivalent of base per equivalent of nitrate ion. The preferred range is from about 0.3 to about 0.6 equivalent of base per equivalent of nitrate ion.
- The thermally stimulated oxidation of the leuco dye by the nitrate salt can be facilitated by the presence of an acid. The acids optionally useful in the thermographic system of this invention are acids as generally known to the skilled chemist. Organic acids, preferably those having carboxylic groups, such as phthalic acid, are preferred, but inorganic acids can also be used. The acid can be present in a ratio of from 0 to 10 times the amount of the nitrate ion.
- The leuco dye, nitrate salt, base having a pKa > 0, and acid, when employed, are dissolved in a binder, which binder is neither strongly basic nor strongly acidic but which is sufficiently polar to hold the constituents in solution. It is preferred that the binder be selected from polymeric materials. Such resins as polyvinyl acetals, e.g., polyvinyl butyral, polyvinyl resins, polyvinylpyrrolidone, polyesters, polycarbonates, polyamides, polyacrylates, cellulose esters, copolymers and blends of these classes of resins, can be used. Saran, a vinyl chloride-vinylidene chloride copolymer, is particularly preferred. Natural polymeric materials such as gelatin and gum arabic can also be used.
- The leuco dye should be present at a concentration of at least 0.3% by weight, based on the weight of the binder, preferably at a concentration of at least 1% by weight, based on the weight of the binder, and most preferably at a concentration of from 2 to 10% or more by weight, based on the weight of the binder.
- A formulation which can be applied by conventional coating techniques can be produced by dissolving the leuco dye, the metal nitrate, and the polymeric binder, together with an organic acid, and, optionally, a conventional stabilizing compound, e.g. catechol, phenidone, along with the base whose conjugate acid has the required pKa in an inert organic solvent, such as, for example, acetone, methyl ethyl ketone, or tetrahydrofuran.
- The formulation can be coated onto a support by methods well known in the art, such as, for example, wire-wound rod, knife, or extrusion coating. Typical wet thickness of the layer can range from about 10 to about 100 micrometers (pm), and the layer can be dried in forced air at temperatures ranging from 20 C to 50 C. It is preferred that the coating thickness be selected to provide maximum image densities greater than 0.2, and more preferably in the range of 0.5 to 1.5, as measured on a MacBeth Color Densitometer Model TD 504 using the color filter complementary to the dye color.
- The support material can be selected from a wide range of materials, including paper, glass, polymeric film, and the like, depending upon the particular imaging requirement. Preferred materials include polymers having good heat stability, such as polyesters. A particularly preferred polyester is polyethylene terephthalate.
- The following examples, which are illustrative rather than limiting or delineative of the scope of the invention, serve to describe the compositions and properties of the present invention.
- These examples demonstrate the effect of adding amines which have conjugate acids with a pKa >0 to the thermally imageable composition contemplated for this invention.
- These examples demonstrate the effect of adding amides and ureas which have conjugate acids with pKa values between about 0 and 2 to the thermally imageable composition contemplated for this invention. Samples were prepared as described in Examples 1-3. Again stock solutions of additives were made containing 0.5 millimole/g of total solution and the amounts indicated in Table II were added to the samples. All samples were coated and dried identically to those described in Examples 1-3. The percentage of spotting was determined for each sample, and is listed in Table II:
-
- These examples demonstrate the effect of adding salts of organophosphoric acids, of or- ganophosphonic acids, or of organophosphinic acids, or phosphines which have pK>O to the thermally imageable composition contemplated for this invention. A procedure identical to that described in Examples 1-3 was used and the results are shown in Table V:
- Various modifications and alterations of this invention will become apparent to those skilled in the art without departing from the scope of this invention, and it should be understood that this invention is not to be unduly limited to the illustrative embodiments set forth herein.
Claims (12)
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US60047484A | 1984-04-16 | 1984-04-16 | |
US600474 | 1984-04-16 |
Publications (3)
Publication Number | Publication Date |
---|---|
EP0159874A2 EP0159874A2 (en) | 1985-10-30 |
EP0159874A3 EP0159874A3 (en) | 1986-06-04 |
EP0159874B1 true EP0159874B1 (en) | 1991-07-24 |
Family
ID=24403749
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP85302573A Expired - Lifetime EP0159874B1 (en) | 1984-04-16 | 1985-04-12 | Prevention of spotting in thermal imaging compositions |
Country Status (6)
Country | Link |
---|---|
EP (1) | EP0159874B1 (en) |
JP (1) | JPH0671823B2 (en) |
AU (1) | AU580034B2 (en) |
BR (1) | BR8501734A (en) |
CA (1) | CA1236299A (en) |
DE (1) | DE3583524D1 (en) |
Families Citing this family (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5278031A (en) * | 1992-10-23 | 1994-01-11 | Polaroid Corporation | Process for thermochemical generation of squaric acid and for thermal imaging, and imaging medium for use therein |
ATE458621T1 (en) * | 2007-09-10 | 2010-03-15 | Mitsubishi Hitec Paper Flensbu | HEAT SENSITIVE RECORDING MATERIAL |
Family Cites Families (13)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3460964A (en) * | 1964-11-19 | 1969-08-12 | Eastman Kodak Co | Heat-sensitive recording element and composition |
GB1330984A (en) * | 1970-09-28 | 1973-09-19 | Fuji Photo Film Co Ltd | Colour-developer compositions |
US4032690A (en) * | 1975-01-24 | 1977-06-28 | Mitsubishi Paper Mills, Ltd. | Thermosensitive recording material |
DE3070044D1 (en) * | 1979-12-07 | 1985-03-07 | Minnesota Mining & Mfg | Color imaging system |
US4423137A (en) * | 1980-10-28 | 1983-12-27 | Quixote Corporation | Contact printing and etching method of making high density recording medium |
AT372910B (en) * | 1980-10-28 | 1983-11-25 | Manuel Ing Cespon | COATINGS FOR THE PRODUCTION OF A PRESSURE-SENSITIVE RECORDING MATERIAL |
JPS5790085A (en) * | 1980-11-27 | 1982-06-04 | Pilot Ink Co Ltd | Thermochromic material |
JPS5798392A (en) * | 1980-12-10 | 1982-06-18 | Toppan Printing Co Ltd | Thermosensitive recording |
US4423139A (en) * | 1980-12-22 | 1983-12-27 | Minnesota Mining And Manufacturing Company | Stabilizer combination for dye oxidation |
US4379835A (en) * | 1980-12-22 | 1983-04-12 | Minnesota Mining And Manufacturing Company | Black image from a thermographic imaging system |
JPS57167380A (en) * | 1981-04-08 | 1982-10-15 | Pilot Ink Co Ltd | Thermochromic material |
JPS59120492A (en) * | 1982-12-27 | 1984-07-12 | Pilot Ink Co Ltd | Reversible heat-sensitive recording material |
CA1243317A (en) * | 1983-04-05 | 1988-10-18 | Harvey A. Brown | Thermographic system using naphthoylated leuco phenazine dyes |
-
1985
- 1985-03-07 CA CA000475897A patent/CA1236299A/en not_active Expired
- 1985-03-13 AU AU39800/85A patent/AU580034B2/en not_active Ceased
- 1985-04-12 EP EP85302573A patent/EP0159874B1/en not_active Expired - Lifetime
- 1985-04-12 DE DE8585302573T patent/DE3583524D1/en not_active Expired - Fee Related
- 1985-04-12 BR BR8501734A patent/BR8501734A/en not_active IP Right Cessation
- 1985-04-15 JP JP60080044A patent/JPH0671823B2/en not_active Expired - Lifetime
Non-Patent Citations (1)
Title |
---|
PATENT ABSTRACTS OF JAPAN, vol. 6, no. 190 (M-159) [1068], 29th September 1982; & JP - A - 57 98 392 (TOPPAN INSATSU K.K.) 10-12-1980 * |
Also Published As
Publication number | Publication date |
---|---|
AU580034B2 (en) | 1988-12-22 |
EP0159874A3 (en) | 1986-06-04 |
BR8501734A (en) | 1985-12-10 |
CA1236299A (en) | 1988-05-10 |
DE3583524D1 (en) | 1991-08-29 |
JPS60234885A (en) | 1985-11-21 |
EP0159874A2 (en) | 1985-10-30 |
JPH0671823B2 (en) | 1994-09-14 |
AU3980085A (en) | 1985-10-24 |
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