|Publication number||US3852093 A|
|Publication date||Dec 3, 1974|
|Filing date||Dec 13, 1972|
|Priority date||Dec 13, 1972|
|Also published as||CA981453A, CA981453A1, DE2362377A1, DE2362377B2|
|Publication number||US 3852093 A, US 3852093A, US-A-3852093, US3852093 A, US3852093A|
|Inventors||Leary K O|
|Original Assignee||Minnesota Mining & Mfg|
|Export Citation||BiBTeX, EndNote, RefMan|
|Patent Citations (7), Referenced by (17), Classifications (9)|
|External Links: USPTO, USPTO Assignment, Espacenet|
United States Patent OLeary Dec. 3, 1974 [541 HEAT-SENSITIVE COPY-SHEET 3,682,684 s/1972 Newman et a1 117/369 3,684,552 8/1972 Wiese et a1. 117/368  inventor W" OLeary, Mmneapohs 3,715,213 2/1973 Nihyakumen 6131 117/369 x Minn. 3,730,677 5/1973 Kalopissis et al. 8/l0.2 3,751,249 8/1973 Hiller.....; 117/368 X  Asslgnee' Mmnesota Mmmg Manufacturmg 3,764,333 10 1973 Leclair 61231 117 369 x Company, St. Paul, Minn.  Filed: D 13, 1972 Primary ExaminerThomas .1. Herbert, Jr. 21] A L 314 7 Attorney, Agent, or Firm-Alexander, Sell, Steldt &
- DeLaHunt  US. Cl. ll7/36.8, 117/369, 260/65 T 51 Int. Cl 841m 5/00 ABSTRA T  Field of Search ..l17/36.9, 36.2, 36.8; A transparent Colored film product, which becomes 8/10-2; 250/65 T clear and colorless at image areas when heated thermographically, contains a p-quinoneimine color body  References C'ted and a mild reducing agent.
UNITED STATES PATENTS 9/1971 Wiese..... 250/65 T 7 Claims, No Drawings HEAT- SENSITIVE COPY-SHEET This invention relates to thermographic copying, wherein a copy of a differentially radiation-absorptive original is made on a heat-sensitive copy-sheet product held in'heat-conductive contact therewith by briefly exposing the original to intense infra-red radiation. In one aspect the invention relates to novel heat-sensitive copy-sheet products. In a particularly important aspect the invention relates to copy-sheet products useful in making negative color projection transparencies.
Negative-acting copy-sheets adapted for making color projection transparencies have previously been described. In US. Pat. No. 3,609,360 the decolorization involves the heat-induced decomposition of a colored reaction product of components including a volatilizable acid which is then released to the atmosphere. U.S. Pat. No. 3,684,552 somewhat analogously uses an amine-reactive color body and a heat-decomposable salt of a nitrogenous organic base.
The present invention employs a different class of color bodies and a different reaction system, and provides a heat-sensitive copy-sheet product which when locally heated, as in the thermographic copying process, is converted from a highly colored to a substantially colorless, and preferably a clear and transparent, form at the heated image areas without release of volatile decomposition products.
The heat-sensitive copy-sheet products of the present inventioncontain p-quinoneimine color bodies which undergo decolorization when heated at thermographically induced temperatures in reactive association with a mild reducing agent. The color body is supplied in a matrix of film-forming binder as a coating on a paper, transparent film or other carrier or as a self-supporting film. The reducing agent may be incorporated in the same matrix, or in an adjacent stratum supported on the carrier or on a separate carrier. A particularly useful structure comprises a transparent flexible film carrier coated with a first stratum of p-quinoneimine color body in a transparent binder and overcoated with a mild reducing agent in a separate binder. Brief heating of the film product causes migration of at least one of the reactants and results in a decolorization of the color body at the heated area.
Reducible p-quinoneimine color bodies which are useful in the preparation of heat-sensitive copy-sheets of the invention include those having thestructural formula.
wherein Ar is an aromatic radical and the R, R, R"
and R' substituent radicals may be hydrogen, halogen, alkyl, alkoxy or amido, or wherein substituent radicals on adjacent carbon atoms may complete a fused polycyclic or heterocyclic ring, all as exemplified by 2 2-chloro-2'-methyl-N,N-diethylindoaniline 2-chloro-N(p-diethylamino-2-methylphenyl)-pbenzoquinoneimine 2-acetamido-N,N,-diethylindoaniline 3-methoxy-2'-methyl-N,N-diethylindoaniline N-( l-naphthyl )-p-benzoquinoneimine N-(2-naphthyl)-p-benzoquinoneimine N-(p-acetylphenyl)-p-benzoquinoneimine 2,6-dichloroindophenol sodium salt 2,3',6-trichloroindophenol sodium salt 2,6-dibromoindophenol sodium salt 2,5-dibromo-N(2,4-dibromophenyl)-pbenzoquinoneimine N-(p-diethylamino-Z-methylphenyl )-l ,4-
naphthoquinoneimine N-(p-diethylamino-2-methylphenyl )-5 ,8-
quinolinoquinoneimine N-(2,4-diamino-5-methylphenyl)-pbenzoquinoneimine trihydrate indoferron N-(p-diethylamino-2-methylphenyl)-2-carboxylic-l 4-naphthoquinoneimine N-(p-dimethylaminophenyl l ,4-
naphthoquinoneimine The following mild reducing agents have been found a useful:
2,5-dihydroxybenzoic acid chlorohydroquinone 2,5-dichlorohydroquinone tetrachlorohydroquinone bromohydroquinone diiodohydroquinone phenylhydroquinone 2,6-di-t-butylhydroquinone 2,S-di-t-butylhydroquinone 2,5 bis( 1,1-dimethylpropyl) hydroquinone 2,5-di-pentylhydroquinone trimethylhydroquinone t-butylhydroquinone methylhydroquinone catechol 3-methylcatechol 4-methylcatechol 4-t-butylcatechol 3-isopropylcatechol v4-isopropylcatechol 4-t-octylcatechol 3,5-diisopropylcatechol 3,6-diisopropylcatechol 3,5-di-t-butylcatechol 3-t-butyl-5-methylcatechol 3-methyl-5-t-butylcatechol 3-methyl- 5-octylcatechol 3-methoxycatechol tetrabromocatechol resorcinol 4-ethylresorcinol 4-n-propylresorcinol 4'-phenylazoresorcinol 4,6-dichlororesorcinol o-hydroxyethylresorcinol 2,6-dihydroxybenzoic acid 2,4-dihydroxybenzaldehyde 2, 6'-dihydroxyacetophenone 2,4,6-trihydroxyacetophenone methyl gallate butyl gallate l ,2,3-trihydroxybenzene 2 ,3 ,4 -trihydroxydecanophenone l ,2,4-trihydroxybenzene 2,4,5-trihydroxybutyrophenone o-aminophenol m-aminophenol p-aminophenol 4-amino-2,-dibromophenol 4-amino-2,6-dichlorophenol 2-amino-4-chlorophenol 3-diethylaminophenol 2,4-diaminophenol p-benzylaminophenol 4-amino-2,S-dimethylphenol -amino-m-cresol 4-amino-m-cresol S-amino-l -naphthol m-hydroxydiphenylamine 4-aminoacetanilide 2,6-diaminotoluene 3,4-diaminotoluene 1,4-diaminobenzene 1,8-diaminonaphthalene tetramethyl-l ,4-diaminobenzene furoin 1,3-dihydroxyacetone L-ascorbic acid arabo-ascorbic acid 4-methoxyl -naphthol Z-methoxy-l-naphthol l-amino-2-methoxynaphthalene 2,3-naphthalene diol 1,4-naphthalene diol 5 ,S-dihydroxyl ,4-dihydro-2-methylnaphthalene l-naphthol Strong reducing agents may also be used in some cases, in particular with the lower molecular weight color bodies and in constructions involving separate sheets, but are presently of only minor interest.
Binder systems may include such polymeric materials as polystyrene, styrene-acrylonitrile or sytrene-acrylate copolymers, styrene-butadiene-acrylonitrile terpolymers, polyvinylchloride, vinyl chloride-vinyl acetate copolymers, vinylidene chloride-acrylonitrile or vinylidene chloride-vinyl acetate copolymers, polyacrylates, polyvinyltoluene. These polymers are moistureresistant, being incapable of absorbing more than about one percent of water, and are preferred as contributing to the stability of the sheet materials during prolonged storage both before and after imaging.
The concentration of color body in the color stratum must be sufficient to impart a distinctive color but excessive amounts require undesirably large quantities of reducing agent, or excessive heating, or may reduce the transparency of the stratum and accordingly are to be avoided. Similarly, the amount of reducing agent available per unit area should be sufficient to react with all of the color body but need not be greatly in excess of that amount and, at least for single sheet projection transparencies, should be well within the range of full compatibility with the binder so that the stratum remains clear and non-light-diffusing.
The following Examples, in which all proportions are in parts by weight unless otherwise indicated, will further illustrate the practice of the invention which however is not to be construed as limited thereto.
EXAMPLE 1 A carrier film of 2 mil (0.05 mm.) ethylene glycol terephthalate polyester film primed with a trace coating of terpolymer primer is supplied with first and second reactant strata, with intermediate and final drying, as follows:
First stratum 2-chloro-2'-methyl-N,N-diethylindoaniline polyvinyl chloride-acetate (Geon 42 l resin) methylethyl ketone toluene dry at IF. coating weight, dry, 2.5 g./sq. m.
Second stratum tertiarybutylhydroquinone polyvinyl butyral (Butvar B-76 resin) nitrocellulose (A see.) I methanol 8 dry at F. coating weight, dry, 4.0 g./sq. m.
EXAMPLE 2 A solution containing 2-chloro-2'-mcthyl-N,N-dimethylindoaniline 0.6 polyvinyl chloride-acetate (VYNS" resin) l2.() methylethyl ketone 96 toluene 12 is applied to thin polyester film and dried in an oven at F. The dried coating is a deep blue in color and weighs 4.7 g./sq. m.
A solution containing tertiary butyl hydroquinone l h sec. nitrocellulose l polyamidc (Elvamidc 8061" resin) l methanol 97 is applied over the first coating at approximately the same wet coating thickness and is promptly dried in the 150F. oven.
The resulting film is imaged in a thermographic copying machine to provide a negative color projection transparency as in Example 1.
EXAMPLE 3 First trip solution 2-chloro-2'-methyl-N,N-diethylindoaniline polystyrene (Styron 690" resin) methylethyl ketone Second trip solution tertiarybutyl hydroquinone 13.5% solution of nitrocellulose in methanol 13.5% solution of polyvinylbutyral in ethanol Coating weights and procedures are as described in previous Examples. By thermographic copying a good negative color projection transparency is obtained.
and 9 parts of polyvinyl butyral resin in 91 parts of ace- EXAMPLE 4 tone, coated on thin (21 V2 lb/ream) glassine. Substantially the same results are obtained.
First trip solution 2-chlore-2-methyl-N,N diethylindoaniline 0.50 5 EXAMPLE 8 vinyl chloride-acetate polymer (Geon 421 resin) 75 acetone 67.5 Flrst coat Second trip solution t-butyl hydroquinone 1.3 21 clellulose "o-200 resin) 5 2-chloro-2'-methyl-N,N-diethylindoaniline 0.25 at 95 polyvinyl chloride-acetate l l0 methylethyl ketone 90 Procedures and results are generally as described in preceding Examples. The solution is applied at an orifice of 3 mils (0.075 mm.) to map overlay tracing paper and is thoroughly EXAMPLE dried 15 Second coat First trip solution 2-chloro-2'-methyl-N,N-diethylindoaniline 0.25 vinyl chloride-acetate polymer 5 4-meth xy-ln ph hol l5 methylethyl ketone 36 polyvinyl butyral 30 toluene 9 titanium dioxide pigment 10 Second trip solution ethanol 222 t-butyl hydroquinone 5 methanol 35 acrylate latex (unhoplex A061"), 45% MM 36 The mlxture 1s homogemzed by prolonged m1ll1ng 1n polloidal silica o A 24 a ball mill, applied over the first coat at the same orifice, and dried. Introduction of silica improves the resistance of the 25 Th coated Sheet id a hi image against an coating to surface picking and roughening during theropaque bl b k d when used as a then-n0 mographic copying without appreciably reducing the hi h clarity. Procedures and results are substantially as described in the preceding Examples. 1 EXAMPLE 9 EXAMPLE 6 F st coat methyl gallate 3 sohmon A ethyl cellulose 5 N-(p acetylphenyl)-p-benzoqu1none1mme 0.4 ethanol 95 polyvinyl chloride-acetate (VYNS" resin) 5 methylethyl ketone 40.5 l
toluene Coated on 2-m1l (0.05 mm.) polyester film at 2 ml Solution B methyl hydroquinone m (0.05 mm.) orifice, and dried.
polyvinyl chloride-acetate (VYHH" resin) 2 Second coat polyvinyl butyral (Butvar 8-76 resin) 10 methylethyl ketone 76 40 Solution A is applied to thin 2 mil (0.05 mm.) polyese 2,6-dichloroindophenol sodium salt 0.3 ter f1lm from a coater bar at a 2 ml (0.05 mm.) orifice polystyrene acrylonimle (Tym resin) l5 and the coatmg 1s dried. S milarly, solut1on B is coated acetone 85 at the same thickness on a separate portion of 1 mil (0.025 mm.) film and the coating is dried. The two sheets are placed in face-to-face contact. The composite is placed against a printed original which is then subjected to brief exposure to intense infra-red radiation. Th p duct provides a negative color projection The second sheet is peeled from the first, leaving a pro transparency b thermographic copying jection transparency withclear image areas and yellow 1 background areas. EXAMPLE 10 EXAMPLE 7 Coated over first coat at 2 mils (0.05 mm.) and dried.
To a solution of 0.08 part 2,6-dichloro-N(pmorpholinophenyl)-p-benzoquinoneimine and 5 parts A f 1 f m 1 h 1 d r11 1 2-chloro-2'-methyl-N,Ndiethylindoaniline 0.25 0 F P ymefo me y met y ate f e y ypolyvinyl chloride-acetate 5 late 1n 20 parts of methylethyl ketone 1s added 0.45
:gfgg'j 2; part of 2,5-dihydroxybenzoic acid and the mixture is Solution B quickly coated on transparent film and dried. The sheet t-butyl hydroquinone W ethyl cellulose (mom resin) l0 .prov1des a color pro3ect1on transparency when printed ethanol I 80 thermographically but is found to have short shelf life,
the initial magenta color gradually fading during stor- The solutions are coated on separate sheets of thin age. Some improvement in performance may be polyester film, and the two sheets are combined and achieved by increasing the proportion of binder but processed, as in Example 6, with similar results. these sheets are generally less permanent and hence As an alternate structure a second sheet is prepared less desirable than those in which the 'tWO reactants are from a solution of ten parts of t-butyl hydroquinone in separate strata.
EXAMPLE 11 First solution N-(p-diethylamino-Z-methylphenyl)-5,8-
quinolino quinoneimine polyvinyl chloride-acetate 6 mcthylethyl kctonc 44 nickel resinutt: q.v Second solution tertiarybutyl hydroquinone 0.67
13.5% solution of nitrocellulose in methanol 8 l3.5% solution of polyvinylbutyral in ethanol 2 EXAMPLE [2 First coat N-( l'naphthyll-p-benzoquinoneimine 0.3 polyvinyl chloride-acetate 0.5 methylcthyl ketone 25 toluene 24.5 Coated at .05 mm. on polyester film and dried.
Second coat stannous chloride 1 vinyl acrylate latex (Ucar 360) (55% NVM) O Simple contact heating with heated type or stylus is also effective and permits more accurate determination of temperature if desired for comparison or test purposes.
What is claimed is as follows:
1. Colored sheet material capable of undergoing localized loss of color when thermographically heated in presence of a reducing agent and containing a pquinoneimine color body in a film-forming binder, wherein said color body has the structure wherein Ar is an aromatic radical and the R, R, R and R' substituent radicals may be hydrogen, halogen, alkyl, alkoxy or amido, or wherein adjacent substituent radicals may constitute a fused polycyclic or heterocyclic ring.
2. Sheet material of claim 1 disposed in face-to-face relationship with a second sheet containing said reducing agent.
3. Sheet material of claim 1 wherein is included a said reducing agent.
4. Sheet material of claim 3 wherein said reducing agent is a hydroquinone, catechol, resorcinol or trihydroxy-aromatic mild reducing agent.
5. Sheet material of claim 3 wherein said reducing agent is contained in said binder.
6. Sheet material of claim 3 wherein said reducing agent is contained in a different film-forming binder as a separate stratum adjacent the stratum containing said color body.
7. Sheet material of claim 6 wherein said strata are supported on a thin flexible transparent film carrier.
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|US3682684 *||Mar 10, 1971||Aug 8, 1972||Minnesota Mining & Mfg||Wide latitude heat-sensitive copy-sheet and method of making|
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|US9708463||Jan 14, 2015||Jul 18, 2017||International Business Machines Corporation||Recyclate verification|
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|U.S. Classification||503/202, 430/334, 430/964, 430/339|
|International Classification||B41M5/36, B41M5/28|
|Cooperative Classification||B41M5/286, Y10S430/165|