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
  • B41M5/382—Contact thermal transfer or sublimation processes
  • B41M5/38235—Contact thermal transfer or sublimation processes characterised by transferable colour-forming materials
• • 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
  • B41M5/323—Organic colour formers, e.g. leuco dyes
• • 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
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/31504—Composite [nonstructural laminate]
  • Y10T428/31786—Of polyester [e.g., alkyd, etc.]
  • Y10T428/3179—Next to cellulosic

Definitions

• the transparent film may consist of a protonatable chromogenous dye-forming color progenitor in a vinyl halide resin binder coated on a thin transparent supporting film.
• An acid source sheet for example, containing salicyclic acid is placed against the coating and is heated thermographically at image areas. The acid is volatilized and reacts with the color progenitor to form a colored image.
• the present invention likewise makes use of an acid source sheet such as that described in Berg et al., to-
• the films of the present invention produce images which are initially strongly colored and-which remain strongly colored under longcontinued exposure.
• the invention makes use of a novel combination of color-formers.
• One of them represents a known -trimethyl-class, herein referred to also as Class A, of protonatable color. progenitors which on reactive contact with a weak acid are promptly converted onehalf color-bodies.
• the other represents a second class (Class B) of oxidizable amine color-forming compounds which only gradually develop a moderately strong color when first acidified with an acid such as salicylic acid.
• the two color-forming components are themselves Substantially colorless. They are conveniently applied to a suitablesubstrate from solution in a volatile liquid vehicle containing a film-forming binder.
• a transparent thin film e.g., polyethylene gycol terephthalate polyester, serves as a preferred form of permanent substrate where the product is to be used as a projection transparency, but paper or other non-transparent substrates or carriers may be used where transparency is not a requirement.
• the binder may itself serve as a carrier where exceptionally thin sheet structures are desired.
• the liquid mixture is spread uniformly over the permanent or temporary substrate surface and the volatile vehicle removed by evaporation.
• an acid source sheet and a color-forming film in face-to-face relationship are ad'- herently tabbed or fastened together along one margin and with a thin acid-impervious separator sheet or film loosely laid between.
• Glassine or non-porous paper preferably coated with a thin layer of vinyl chloride polymer or the like, makes an effective separator.
• the separator film is. first withdrawn, leaving the coated surfaces in contact.
• a graphic original is placed against the couplet and is briefly subjected to intense radiation in a thermographic copying machine.
• a colored image of the original is produced on the color-forming sheet, which is then removed from the acid source sheet, being provided with a row of perforations adjacent the margin for that purpose.
• the imaged sheet serves as a color projection transparency.
• the color density of the image is initially high and is maintained at a high level both during prolonged projection and under prolonged exposure to heat and humidity in accelerated aging tests.
• Protonatable chromogenous dye-forming color progenitors useful in the sheet materials of the present invention are represented by compounds such as the following:
• dimethylindolenine as described by Berg et al. They convert to a colored modification promptly upon treatment with salicylic acid vapor.
• Class B compounds are capable of being oxidized in an anionogenic environment to yield colored products which are styryl or cyanine dyes. Conveniently prepared by chemical reduction of such dyes, e.g., with sodium borohydride, these Class B compounds have as their basic structure the linkage wherein R is lower alkyl and R R, and R either separately or in combination represent skeletal structures including a total of at least about six carbon-to-carbon double bonds in conjugate arrangement with the N-C bond. Typical and preferred examples of these Class B compounds include the following:
• the amounts of colorforming materials will be proportioned to provide and maintain a substantially constant image density sufficient to project a colorful and easily visible image; but disproportionation of materials, to provide either increase or decrease in image density during continued projection or upon aging, is likewise contemplated.
• Polyester films as above described are heat-resistant, dimensionally stable, and transparent, and are preferred; but films of cellulose or derivatives, vinyl polymers, and other film-forming materials are also useful.
• film-forming binders may be selected from a wide variety of wellknown materials used for such purposes, including ethyl cellulose, vinylchloridevinyl acetate copolymers, cellulose acetate butyrate, polyvinylacetate, polymethylmethacrylate, polyvinylbutyral, styrene-acrylonitrile copolymer.
• EXAMPLE 1 Color projection transparency films are prepared by coating transparent polyester film with solutions in acetone of styrene-acrylonitrile resin (Tyril 880 binder and colorforming materials. The coatings are applied at a thickness of two mils (0.05 mm.) and dried in a forced air oven maintained at 180 F. Segments of the films are placed against an acid source sheet as previously described and the composites are locally heated by thermographic copying procedures. A portion of each segment is placed on an overhead projector and illuminated for fifteen minutes. The optical density of the image is measured for both segments, and is reported after correction for background density which is usually on the order of 0.01-0.15. The segments are then placed in an accelerated aging chamber and held for several days, i.e., until each reaches substantially constant color value, under conditions of 105 F. and relative humidity, whereupon the image density is again determined and recorded.
• Tyril 880 binder and colorforming materials The coatings are applied at a thickness of two mils (0.05 mm.) and dried in
• Compound A is N-(n-butyl)-N-(bis- (dimethylaminophenyl) methylene urea), a protonatable color progenitor which on protonation produces a magenta color.
• Compound B is 2-(4-dimethylaminostyryl)-l,3,3- trimethylindolene, an oxid'izable N-hydrocarbyl monosubstituted dihydroheterocyclic tertiary amine color precursor. Oxidation of this compound in an acidic medium likewise produces a magenta color.
• EXAMPLE 2 Transparencies are prepared and tested as in Example 1 except for substitution of compounds.
• Compound A is 2-(p-hydroxystyryl)-3,3-dimethylindolenine.
• Compound B is 2-( 2-pyrrole styryl)-1,3,3- trimethylindolene.
• the sheet produces a yellow image.
• the optical densities are as tabulated:
• EXAMPLE 5 The relative amounts of N-bis(p-dimethylaminophenyl)-methyl) morpholine as Compound A and of 2-(4,4-bis) -4-dimethylaminophenyl))-butadienyl- 1,3,3-trimethylindoline as Compound B are varied in a series of coatings prepared and tested otherwise as in the preceding normal" examples and at daily intervals cient density or have deteriorated to below the desirable level. Similar trends may be determined for combinations of other specific compounds in similar manner. Images with density values of as little as 0.2 to 0.3 above background produce a visible image on the projection screen; but initial densities of at least about 0.80 are desirable for most purposes.
• the salicylic or equivalent acid is transferred to the color forming sheet from a separate removable acid source sheet.
• Integral sheets wherein the volatilizable acid is contained in a separate coating, preferably with an intermediate temporary barrier layer, are also useful particularly where projection transparency is not required.
• Sheet material which rapidly develops a longlasting color when first briefly subjected to vapors of salicylic acid, having an active color-forming stratum comprising a mixture of (A) a protonatable chromogenous dye-forming color progenitor and (B) a substantially colorless oxidizable Nhydrocarbyl-substituted dihydroheterocyclic amine precursor of a styryl or cyanine dye.
• Sheet material of claim 1 wherein the 8" component is a 1,3,3-trimethyl indolene.
• Sheet material of claim 1 including a transparent carrier film and wherein said stratum includes a polymeric film-forming binder.
• Image densities of at least about 0.65-0.70 are desired for fully commercially acceptable images on color projection transparencies. It will be seen that after prolonged aging, samples 1-3, 6 and 7, as well as that of Example 3, meet this requirement, whereas the remaining samples have either failed initially to provide sufficontains thefA and B components in a ratio of from about 2:1 to about 1:2.
• a copy-sheet assembly useful in making a color projection transparency copy of a graphic original by the thermographic copying process and consisting of a color-forming film member and an acid source sheet binder of a protonatable chromogenous dye-forming color progenitor and an oxidizable N-hydrocarbyb substituted dihydroheterocyclic amine precursor of a styryl or cyanine dye.
• Col. 1 line 35, "tri-methylclass” should read first class Col. 1, line 38, "one-half” should read to Col. 1, line 60, after e.g. insert of Col. 4, line 6, "colorforming” should read color-forming Col. t, line 35, "The formulations and results are as follows: second occurrence should be omitted.

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• Physics & Mathematics (AREA)
• Optics & Photonics (AREA)
• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• General Chemical & Material Sciences (AREA)
• Heat Sensitive Colour Forming Recording (AREA)
• Non-Silver Salt Photosensitive Materials And Non-Silver Salt Photography (AREA)
• Color Printing (AREA)

Priority Applications (11)

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Cited By (4)

Citations (3)

Family Cites Families (1)

• 1973
  • 1973-04-02 US US34719473 patent/US3856552A/en not_active Expired - Lifetime
• 1974
  • 1974-02-22 CA CA193,259A patent/CA1011550A/en not_active Expired
  • 1974-03-22 SE SE7403894A patent/SE387276B/xx not_active IP Right Cessation
  • 1974-03-29 FR FR7411421A patent/FR2223196B1/fr not_active Expired
  • 1974-04-01 GB GB1443674A patent/GB1461093A/en not_active Expired
  • 1974-04-01 JP JP3688474A patent/JPS5739954B2/ja not_active Expired
  • 1974-04-01 BR BR256774A patent/BR7402567D0/pt unknown
  • 1974-04-01 DE DE2416088A patent/DE2416088C2/de not_active Expired
  • 1974-04-01 AU AU67385/74A patent/AU476305B2/en not_active Expired
  • 1974-04-01 CH CH452374A patent/CH587126A5/xx not_active IP Right Cessation
  • 1974-04-02 IT IT4995474A patent/IT1005906B/it active

Patent Citations (3)

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