Classifications

• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03C—PHOTOSENSITIVE MATERIALS FOR PHOTOGRAPHIC PURPOSES; PHOTOGRAPHIC PROCESSES, e.g. CINE, X-RAY, COLOUR, STEREO-PHOTOGRAPHIC PROCESSES; AUXILIARY PROCESSES IN PHOTOGRAPHY
  • G03C1/00—Photosensitive materials
  • G03C1/52—Compositions containing diazo compounds as photosensitive substances
  • G03C1/61—Compositions containing diazo compounds as photosensitive substances with non-macromolecular additives
• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03C—PHOTOSENSITIVE MATERIALS FOR PHOTOGRAPHIC PURPOSES; PHOTOGRAPHIC PROCESSES, e.g. CINE, X-RAY, COLOUR, STEREO-PHOTOGRAPHIC PROCESSES; AUXILIARY PROCESSES IN PHOTOGRAPHY
  • G03C1/00—Photosensitive materials
  • G03C1/52—Compositions containing diazo compounds as photosensitive substances
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10S428/00—Stock material or miscellaneous articles
  • Y10S428/913—Material designed to be responsive to temperature, light, moisture
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10S430/00—Radiation imagery chemistry: process, composition, or product thereof
  • Y10S430/132—Anti-ultraviolet fading

Definitions

• a heat-sensitive copying material comprising a support having a heat-sensitive layer thereon which comprises a primary aromatic amine, an azo coupling component and a compound which is stable at room temperature but which is capable when heated of providing nitrosonium ion in the heated areas of the copying material in an amount sufiicient to diazotize aromatic amine.
• Thermal imaging processes employing such material are also disclosed.
• the invention relates to a heat-sensitive copying material which, when differentially exposed to heat, results in an azo dye image or trace in those areas of the copying material which were so exposed.
• the invention also relates to thermal imaging processes wherein such a copying material is employed, and to the products obtained from such thermal imaging processes.
• thermographic recording is a relatively old and extensive art which comprises a large number of processes and materials designed to be employed in reproducing or recording information through the use of heat as the primary energy source to produce the record or image.
• Thermofax process which uses infra-red light to duplicate the infra-red absorbing heat of an original by way of a direct reflex copying process, as well as processes wherein there is physical contact of heat responsive materials with heated instruments, such as platens or styli to produce an original image.
• This art is to be distinguished, however, from related arts, such as photothermography, wherein the image or latent image is formed, at least in part through the use of light energy, but which may be subsequently developed through the use of heat energy.
• thermographically copying or recording of information and data there are a relatively large number of processes and materials available for use in thermographically copying or recording of information and data, a number of drawbacks have been associated with many of these processes and products.
• some of the prior art processes exhibit relatively narrow latitudes with regard to processing parameters; and many of the prior art thermographic materials require supports having particular properties within fairly narrow limits, are available in a limited number of image colors, some or all of which may not be particularly acceptable from an aesthetic point of view, or require that the heat-reactive components of the material be applied in separate layers and kept out of contact with one another United States Patent 0 ice until the material is thermally developed.
• one or more of the reactants are carried in an entirely separate sheet, which is brought into contact with the copy sheet just prior to its exposure to heat.
• the heat-sensitive copying materials of this invention comprise a support having a heat-sensitive layer thereon comprising (1) a primary aromatic amine which is capable, upon diazotization and coupling, of forming a colored azo dye, (2) an azo coupling component, and (3) a compound which is stable at room temperature, but which is capable, upon heating, of providing nitrosonium ion in an amount sufiicient to diazotize the aromatic amine in the areas of the copying material which are subjected to heat.
• the resultant image or trace which is obtained in the copying materials is an azo dye image
• a wide variety of colors are obtainable with the heat-sensitive copying materials of this invention, depending primarily on the combination of aromatic amine or amines and azo couplers or coupling components which are employed in the heat-sensitive layer.
• the heat-sensitive copying materials are stable materials which can be stored at room temperature over extended periods of time with little or no noticeable deterioration, and they are capable of being used in a number of diiferent thermographic copying processes, including those which apply heat to the copying material by means of convection, conduction, radiation, or reflected radiation.
• the imaged or developed heat-sensitive copying materials of this invention also have an add-on capability, in that they may be re-imaged or re-developed to add additional information or data in addition to that originally obtained upon initial imaging or development.
• the heat-sensitive copying materials of the present invention comprise three essential components: a primary aromatic amine which is capable of being diazotized and coupled to form a colored azo dye; an azo coupling component; and a compound which is stable at room temperature but which is capable, upon heating, of providing nitrosonium ion in an amount sufficient to diazotize the aromatic amine in those areas of the copying material which are subjected to heat.
• a primary aromatic amine which is capable of being diazotized and coupled to form a colored azo dye
• an azo coupling component a compound which is stable at room temperature but which is capable, upon heating, of providing nitrosonium ion in an amount sufficient to diazotize the aromatic amine in those areas of the copying material which are subjected to heat.
• any of the numerous azo coupling components which have been disclosed as being useful in the diazotype processes of the prior art can be employed as the azo coupling components in the copying materials of this invention, and the choice of amine and azo coupling components depends primarily on the color desired in the imaged or developed product.
• the preferred aromatic amines are those which are substantially colorless materials which are resistant to oxidation and are non-hygroscopic and which, upon diazotization, form a diazonium compound which exhibits a high rate of coupling and yields, upon coupling, an azo dye having a high extinction coeflicient and good, bright color.
• Illustrative of such preferred aromatic amines are amines such as dianisidine 0 C H; (I) C H: (Q-Q 4-benzamido-2, S-diethoxyaniline r portion, -Q-r-r l H A OCHzCH: J 4-benzamido-2,5-diethoxyaniline f 0 C H
• any of those which have been found to be useful in preparing conventional diazotype materials can be employed to prepare the heat-sensitive copying materials of this invention.
• an azo-coupling component contains acidic groups in the molecule, these groups should be neutralized before such a coupling component is employed in the heat-sensitive-copying materials of this invention, since the presence of such groups can cause premature diazotization of the aromatic amine, which, in turn, results in premature coupling and formation of the azo dye.
• Illustrative of the azo-coupling components which can be employed in the heat-sensitive copying materials of the present invention are compounds such as resorcinal; 2 methylresorcinol; 4 methylresorcinol; 5 methylresorcinol; 2 methyl 4 ethylresorcinol; 2,4- dichlororesorcinol; 4,6 dichlororesorcinol; 4 chlororesorcinol; 4 bromoresorcinol; 4 iodoresorcinol; 4-fluor0- resorcinol; N(fl hydroxyethyl)rat-resorcylamide; a-resorcylamide; a resorcylic acid; sodium salt; N(phenyl) cc resorcylamide; resorcinol 5 sulfonic acid, sodium salt; resorcinol-4-sulfonic acid, sodium salt; resorcinol-4,6- disulphonic acid, disodium salt;
• Naphthol AS-OL acetate, propionate, furoate, octoate, benzoate, and the like i.e. a compound represented by the formula (iKlHa wherein R represents an acyl radical such as and the like)
• Naphthol AS acetate, propionate, furoate, octoate, benzoate and the like i.e. a compound represented by the formula and the like
• Illustrative of the types of azo-coupling components containing. acidic groups which can be employed in the heat-sensitive copying materials of this invention if the acidic groups are neutralized prior to the use of such coupling components in said materials, are compounds such as 1 hydroxy 2 naphthoic acid; 2 hydroxy- 3-11aphthoic acid; 2 hydroxy 1 naphthoic acid; 2- hydroxy 6 naphthoic acid; 1 naphthol 4 sulfonic acid; 1,8 dihydroxynaphthalene 4 sulfonic acid; 7- resorcylic acid; a-resorcylic acid; fi-resorcylic acid; 2,4,6- trihydroxybenzoic acid; 4 bromo 3,5 dihydroxybenzoic acid; resorcinol-4-sulfonic acid; and the like.
• any compound or combination of compounds which is sufficiently stable at room temperature to avoid prediazotization of the aromatic amine component(s), and yet sufficiently heat-sensitive so that at elevated temperatures nitrosonium ion is liberated in amounts sufiicient to diazotize the aromatic amine, can be employed.
• nitrosonium ion sources for use in the present invention are substituted and unsubstituted ammonium nitrite salts having the general formula or wherein R 18 hydrogen, a substituted or unsubstituted alkyl group containing from 1 to about 6 carbon atoms, a substituted or unsubstituted aralkyl group containing from 7 to about 10 carbon atoms, or a cycloalkyl group containing from 4 to about 8 carbon atoms, and R" is as inorganic salts of nitrous acid with amine salts of organic or inorganic acids.
• alkali metal salts of nitrous acid in combination with amine salts of aromatic organic 5 acids is preferred.
• aromatic organic acid an alkylene group or heteroalkylene group (i.e. an alkylene portion of the amine salt may be an organic carboxylic, group containing a hetero atom such as oxygen, nitrogen, sulfonic, sulfinic or phosphonic acid, amine salts derived sulfur, and the like in the alkylene chain) containing from from a substituted aromatic carboxylic acid such as sali- 3 to about 7 atoms.
• Secondary ammonium nitrite salts i.e. cylic acid are particularly preferred.
• the amine portion of those wherein two of the groups represented by R are 10 the amine salt is preferably derived from an amine having hydrogen) are preferred.
• a pKa of from about 5 to about 11.5 with amines having
• the aforementioned ammonium nitrite salts may be a pKa of from about 8 to about 9 being particularly preadded as a separate and distinct component, or they may ferred.
• Illustrative of the preferred amines are amines such be formed in situ from ammonium nitrite precursors, such as those set forth in the following table:
• N(n-butyD-N-ethanolamine /OH;OHCH2OH CHQCHZOH Di-n-butyl amine CHzCHzCHzCHa 10. 25
• the nitrosonium ion source is an ammonium nitrite salt which is added as a separate and distinct comane, causing the precipitation of the ammonium nitrite salt of whichever amine is employed.
• the ammonium nitrite ponent said salt can be prepared beforehand by slowly 70 salt can be recovered by filtration; and, after being washed adding an aqueous solution of alkali metal nitrite (e.g. a 40% solution of sodium nitrite) to concentrated (96%) sulfuric acid.
• the nitrous acid which evolves from this addition of alkali metal nitrite to concentrated sulfuric with a solvent such as hexane and dried, can be employed as the nitrosonium ion source in the heat-sensitive copying materials of the present invention.
• a solvent such as hexane and dried.
• ammonium nitrite salts such as N-phenyl (a-hydroxy)ethyl-N-cyclohexylammonium nitrite i, am
• the nitrosonium ion source is formed in situ from ammonium nitrite precursors such as an alkali metal nitrite and an amine salt of an aromatic organic acid
• the amine salt of the aromatic organic acid can be prepared beforehand by slowly adding an amine to a concentrated solution of an aromatic organic acid in an appropropn'ate solvent. This reaction is usually exothermic and the amine salt of the acid will separate on cooling.
• an amine salicylate is desired as one of the ammonium nitrite precursors
• the appropriate amine is poured slowly into a concentrated solution of salicylic acid in an organic solvent such as acetone, ether, or methylene chloride; and, after cooling to room temperature and scratching the side of the beaker in which the amine salt is being prepared, the amine salt of salicylic acid precipitates out of the solution and is separated by filtration.
• the amine salt is so insoluble that it precipitates out while the reaction mixture is still hot.
• the alkali metal nitrite and the amine salt of the aromatic organic acid can then be incorporated into the heat-sensitive coating as ammonium nitrite precursors, in order to form the required nitrosonium ion source in situ.
• the nitrosonium ion source which is employed as an essential component in the compositions of this invention decomposes or dissociates under the influence of heat to provide nitrosonium ion in an amount sutficient to diazotize the aromatic amine component which is also present as an essential component in the heat-sensitive copying materials of this invention.
• nitrous acidium ion H NO or a nitrosyl compound (i.e. a compound, NOX, wherein X represents an electronegative group such as Cl-, -HSO or Using 2,5 diethoxy-aniline to represent the aromatic amine component, resorcinol to represent the azo coupling component and diethylammonium nitrite to represent the nitrosonium ion source, the following reaction sequence has been proposed to illustrate a possible mechanism involved in the development of the heat-sensitive copying materials of this invention: (1) Decomposition or dissociation of the nitrosonium ion source upon application of heat to provide nitrosonium ion in quantities sufiicient to diazotize the aromatic amine in those areas of the heat-sensitive copying material which have been subjected to heat CHaCEg/CHzCHz CHzCHz e 2 N ZHNO: :IzONO CHaC 2 If the nitrosonium ion carrier is assumed to be
• nitrosonium ion carrier is the anhydride of nitrous acid (i.e. dinitrogen trioxide) nitrosonium ion can be obtained by way of a similar equilibrium:
• the nitrosonium ion carrier is assumed to be the nitrous acidium ion (i.e. nitrous acid which has extracted a proton from either the free amine or another molecule of nitrous acid)
• the nitrosonium ion can be obtained by way of the following equilibrium:
• the nitrosonium ion carrier may in fact be a nitrosyl compound such as nitrosyl salicylate (i.e. a compound having the formula NOX wherein X represents the salicylate ion).
• nitrosyl salicylate i.e. a compound having the formula NOX wherein X represents the salicylate ion.
• the diethylammonium nitrite in the equilibrium set forth above may react, upon heating, with the sodium salicylate to form nitrosyl salicylate, which provides nitrosonium ion by Way of the following equilibrium:
• these heat-sensitive copying materials can have incorporated therein additional components such as pre-coupling inhibitors, antioxidants, UV (ultraviolet) absorbers, stabilizers, and other types of additives.
• pre-coupling inhibitors antioxidants
• UV absorbers ultraviolet absorbers
• stabilizers and other types of additives.
• nitrosonium ion source or combination of a particular aromatic amine and nitrosonium ion source tends to pre- 21 maturely release nitrosonium ion (e.g. through the premature formation of nitrous acid
• the heat-sensitive copying materials of this invention can also contain antioxidants and UV absorbers, in order to prevent oxidation and/ or discoloration of said materials due to oxygen, heat, light, heavy metal ions or any combination of such oxidation initiators.
• antioxidants and UV absorbers for example, the presence of small amounts of hydroquinone and substituted hydroquinones such as tertiary butyl hydroquinone and chlorohydroquinone have been found to be particularly useful in inhibiting the oxidation and/or discoloration of the aromatic amine component; and the use of UV absorbers which absorb strongly near the visible region of the spectrum has been found to both inhibit the oxidation of one or more of the essential components, and to reduce or eliminate any photoproduction of azo dye.
• UV absorbers are materials such as Tinuvin P (a substituted hydroxyphcnylbenzotriazole) Tinuvin 326, Tinuvin 327 and Tinuvin 328 (UV absorbers sold by Geigy Chemical Corporation of Ardsley, N.Y.), as well as other UV absorbers such as 2,2-dihydroxy 4 methoxy benzophenone.
• the UV absorber can be incorporated into the heat-sensitive layer as an additional component or added to the support which is employed, or it may be applied in a separate layer or over-coat.
• heat-sensitive copying materials of this invention can also be included in the heat-sensitive copying materials of this invention, in order to adjust or maintain the pH of the heat-sensitive layer, thereby improving the stability of the heat-sensitive copying material during storage (Le. improving its shelf-like).
• buffers or pH adjusters can also be included in the heat-sensitive copying materials of this invention, in order to adjust or maintain the pH of the heat-sensitive layer, thereby improving the stability of the heat-sensitive copying material during storage (Le. improving its shelf-like).
• buffers or pH adjusters can also be included in the heat-sensitive copying materials of this invention, in order to adjust or maintain the pH of the heat-sensitive layer, thereby improving the stability of the heat-sensitive copying material during storage (Le. improving its shelf-like).
• Non-hygroscopic, low odor, colorless aliphatic and heterocyclic amines having low vapor pressures have been found to be particularly useful in this regard, with the use of heterocyclic amines such as imidazole being preferred.
• any of the well-known, conventional substrates 0r bases which have been traditionally employed as substrates for diazo-type formulations can be employed as supports in the heat-sensitive copying materials of this invention, the only major requirement being that the support be thermally stable at the temperatures used to image the heatsensitive copying materials comprising such support. Supports which are susceptible to hydrolysis or which tend to release acid over extended periods of time should also be avoided.
• Illustrative of the types of supports which can be employed to prepare the heat-sensitive copying materials of this invention are supports such as cellulose diacetate, cellulose triacetate, ethyl cellulose, polyester, and the like.
• the bonding of the heat-sensitive layer to the support can be improved in many instances by either coating the particular support with a subbing layer of a bonding resin, or by incorporating such a resin into the heatsensitive formulation as an additional component.
• a bonding resin is resins such as polyvinyl butyral, cellulose diacetate, ethyl cellulose, polyvinyl formal, cellulose acetate butyrate, and the like.
• Polyester film having a bonding or subbing layer of cellulose acetate butyrate coated thereon has been found to be particularly useful as a support for the heat-sensitive copying materials of this invention.
• the heat-sensitive copying materials are prepared by coating a solution of the various components onto the proper support using any of the conventional coating techniques, and then drying the coated support at a temperature less than that at which imaging occurs.
• the temperature at which imaging occurs is not narrowly critical and depends to at least some degree on the particular components employed in preparing the heat-sensitive copying materials of this invention.
• the temperature range available in commercial thermocopying machines such as 3M Companys Thermofax machines (e.g. 3M Companys Sec cretary-Model 45CG) has been found to be more than adequate for development of the heat-sensitive copying materials of this invention.
• the heat-sensitive copying material may exhibit a tendency to stick to the original being copied.
• the heat-sensitive material can be top-coated with a protective layer or coating which is inert with respect to the components employed to prepare the heat-sensitive layer, thereby reducing or eliminating entirely the tendency of the heat-sensitive copying material to stick to the surface of the original.
• PPO' polyphcnylene oxide
• the sensitive copying materials of this invention can be employed to make copies such as oflice copies, copies for overhead projectuals, and copies of engineering drawings from originals containing infrared-absorbing images, such as carbon, pigmented ink, and silver images; and such materials can also be employed as chart papers, and the like, which are imaged through the use of devices such as heated styli.
• Example-A heat-sensitive coating formulation was prepared comprising the following components:
• Component Amount Acetone (solvent) ml 60 Methanol (solvent) ml 40 Sodium azide (pre-coupling inhibitor gm 0.07 2-hydroxy-3-naphthoic acid, o-anisidide 1 (azo coupling component) gm 0.71 Dianisidine 2 (aromatic amine) gm 1.32 Di-(acetoacet)-dianisidide 3 (azo coupling component) am 0.83 Sodium nitrite (precursor of the nitrosonium ion source) gm-.. 1.0 Tinuvin P (a substituted hydroxyphenyl benzotriazole UV absorber) gm..
• the formulation was head coated at a rate of approximately feet per minute onto a polyester film support which had been previously coated with a cellulose acetate butyrate bond coat, and the coated support was then dried for four minutes at 130 F.
• the resulting heat-sensitive copying material was subsequently top-coated with a 4% solution of polyphcnylene oxide in trichloroethylene and this additional coating was then dried.
• a sample of the resulting heat-sensitive copying material was imaged by placing the sensitized side of said copying material in intimate contact with a portion of a page from a newspaper and then passing the copying material and the newsprint original while in intimate contact with one another, through a Thermofax Secretary (Model 45CG) thermo- 24 copy machine at a rate of approximately 6 /2 feet per minute.
• a neutral black copy of the newsprint original which was capable of being used as an overhead projection transparency was obtained.
• Examples 2-8.A heat-sensitive coating formulation was prepared comprising the following components:
• the formulation was head coated onto a polyester film support which had been previously coated with a cellulose acetate butyrate bond coat, and the coated support was then dried for four minutes at 115 F.
• the resulting heat-sensitive copying material was then top-coated with a coating formulation comprising the following components:
• Trichloroethylene cc Tinuvin 327 (a UV Absorber sold by Geigy Chemical Corporation of Ardsley, N.Y.) gm 3 40% Solution of Acryloid B-72 (a film forming acrylic resin manufactured by the Rohm and Haas Corporation of Philadelphia, Pa.) in toluene gm Polyphenylene oxide, a film forming resin polymer consisting essentially of the repeating polymer unit 1 g 3 l l CHS In The top-coated, heat-sensitive copying material was dried for four minutes at 115 F., and a sample of the resulting material was exposed while in contact with a master containing an infrared-absorbing image and in a manner similar to that set forth in the preceding example to yield a black copy of the image on the master on a clear background.
• Acryloid B-72 a film forming acrylic resin manufactured by the Rohm and Haas Corporation of Philadelphia, Pa.
• methoxy anilide (Fast Violet B Base) 0 CH; OH i Q @C-N- NHQ OH 4 Same 2-11ydroxy-6-methoxy-3-naphthoic Same Green.
• the azo coupling component was Dibenzylamine a-hydroxy-B-naphthoate Orange.
• Example 9A coating formulation was prepared comprising the following components:
• N-phenyl (a-hydroxy)ethyl-N-cyclohexylamine salicylate P ecursor 0f the nitrosonium ion source
• CHa-CH-Q c 5 4.22 grams
• Precursor of the nitrosonium ion source k5 second butyrate (a low viscosity cellulose acetate butyrate resin used to increase the viscosity of the formulation).
• Example 13 Example 14
• Example 15 Example 16
• Example 16 Example 17 Acetone"...
• each of the above formulations were separately coated onto the same type of substrate as that employed in Examples 2 to 8 rat the rate of 15 feet per minute, and then dried for five minutes at 130 F.
• a sample of each of the heat-sensitive copying materials was then processed through a Termofax Secretary-Model 450G thermocopy machine at a rate of approximately 6 feet per minute with the sensitized side of said sample in direct contact with an infrared-absorbing graphic origi-nal.
• the copy obtained in each instance was suitable for use as an overhead projection transparency.
• the formulation which was used to prepare the heatsensitive copying materials in these examples comprised the following components:
• Component Amount Methanol ml 40 Acetone ml 60 Sodium nitrite "gm-. 1.0 Sodium azide gm 0.02
• N -isopropyl-N -benzylamlne benzene phosphinate 4. 58 2-33 0. 58 0. 04 68.
• 4. 58 -194 0. 50 0. 04 69- N -isopropy1-N -benzyiamine-o-bromobenzoate-- 5, 53 104-106 0. 57 0. 04 70.
• a heat-sensitive copying material comprising a support having a heat-sensitive layer thereon which comproses:
• (C) a nitrosonium ion source which is stable at room temperature, but which is capable upon heating of providing nitrosonium ion in an amount sufi'lcient to diazotize the aromatic amine in those areas of the copying material subjected to heat, said nitrosonium ion source being selected from the class of ammonium nitrite salts having the general formulae:
• ammonium nitrite salt is at least one salt selected from the class consisting of N-isopropyl-N- benzylammonium nitrite; N-(Z-cyanoethyl)-N-cyclohexylammonium nitrite; dibenzylammonium nitrite; N-phenyl (u-hydroxy)ethyl N cyclohexylammonium nitrite; N- (2 chlorobenzyl) N cyclohexylammonium nitrite; and N-benzyl-N-cyclohexylammonium nitrite.
• a heat-sensitive copying material is claimed in claim 6 wherein the amine salt employed to form the ammonium nitrite salt in situ is derived from salicylic acid and an amine having a pKa of from about 8 to about 9.
• ammonium nitrite salt is formed in situ from sodium nitrite and at least one amine salt of salicylic acid selected from the class consisting of N-isopropyl-N-benzylamine salicylate; N (2 cyanoethyl)-N- cyclohexylamine salicylate; dibenzylamine salicylate; N- phenyl (a hydroxy)ethyl-N-cyclohexylamine salicylate; N (2 chlorobenzyl) N cyclohexylamine salicylate and N-benzyl-N-cyclohexylamine salicylate.
• a heat-sensitive copying material as claimed in claim 1 which comprises, as an additional component, at least one pre-coupling inhibitor.
• a heat-sensitive copying material as claimed in claim which comprises as a pre-coupling inhibitor at least one compound selected from the class consisting of sodium azide, hydroquinone, a substituted hydroquinone and an arylsulfinic acid.
• a heat-sensitive copying material as claimed in claim 1 which comprises, as an additional component, an antioxidant.
• a heat-sensitive copying material as claimed in claim 12 which comprises as an antioxidant at least one compound selected from the class consisting of hydroquinone, a substituted hydroquinone, and phenothiazine.
• a heat-sensitive copying material as claimed in claim 1 which comprises, as an additional component, an ultraviolet absorbing material.
• a heat-sensitive copying material as claimed in claim 14 which comprises as an ultraviolet absorbing ma- 34 terial at least one compound selected from the class consisting of a substituted hydroxyphenylbenzotriazole and 2,2'-dihydroxy-4-methoxy benzophenone.
• a heat-sensitive copying material as claimed in claim 1 which comprises, as an additional component, a non-hygroscopic, low odor, colorless, low vapor-pressure aliphatic or heterocyclic amine as a pH adjuster.
• a heat-sensitive copying material as claimed in claim 16 which comprises imidazole as a pH adjuster.
• a heat-sensitive copying material as claimed in claim 1 having a top-coat thereon which comprises polyphenylene oxide.
• nitrosoniumion should be --ni'trosonium .ion--. 9, l0 9" should be -l0.9--.

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• Physics & Mathematics (AREA)
• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• General Physics & Mathematics (AREA)
• Spectroscopy & Molecular Physics (AREA)
• Heat Sensitive Colour Forming Recording (AREA)
• Non-Silver Salt Photosensitive Materials And Non-Silver Salt Photography (AREA)

Applications Claiming Priority (1)

Publications (1)

Family

ID=21888619

Family Applications (1)

Country Status (7)

Cited By (5)

• 1970
  • 1970-05-11 US US36440A patent/US3694247A/en not_active Expired - Lifetime
• 1971
  • 1971-05-03 CA CA112,015,A patent/CA950669A/en not_active Expired
  • 1971-05-04 GB GB1309271*[A patent/GB1354413A/en not_active Expired
  • 1971-05-11 FR FR7116988A patent/FR2091454A5/fr not_active Expired
  • 1971-05-11 DE DE19712123282 patent/DE2123282A1/de active Pending
  • 1971-05-11 BE BE766987A patent/BE766987A/xx unknown
  • 1971-05-11 NL NL7106480A patent/NL7106480A/xx unknown

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