GB1563175A - Heat-sensitive recording composition with mixed colour precursors - Google Patents

Description

(54) HEAT-SENSITIVE RECORDING COMPOSITION WITH MIXED COLOUR PRECURSORS (71) I, WILLIAM RICHARD LAWTON, a Citizen of the United States of America, of 6651 Jewett-Holmwood Road, Orchard Park, New York 14127, United States of America, do hereby declare the invention, for which I pray that a patent may be granted to me and the method by which it is to be performed, to be particularly described in and by the following statement:- This invention relates to recording members containing heat-reactive components and, more particularly to recording members capable of being used in thermographic copying, thermal printing, event recording, and as transparencies for overhead projection.

Heat sensitive sheets containing cyclic polyketo compounds useful for copying and recording and characterized by an ability to form a mark of contrasting color when heated to an activation temperature of 50"C, are known in the art. They are used in thermographic processes wherein a recording member is positioned on a graphic original and exposed to infrared radiation to cause a selective heating of the dark areas of the original sufficient to form a copy thereof on the heat sensitive member. The thermally responsive members have also been used to record the heated portions of a thermal print-head and to record a colored trace when contacted by the hot stylus of a thermal recorder.The ninhydrinamine reaction wherein ninhydrin reacts with amino acids, primary amines, and certain derivatives of morpholine, piperidine, and pyrrolidine to give the dye commonly referred to as Ruhrman's purple is well known. Isatin reacts with these same amines to give isatin blue. Alloxan reacts with the amines to give a red dye. These reactions have been used in numerous inventions for thermally responsive copy and recording papers and films. Lawton, U.S. Patent No. 3,736,166 used ninhydrin with various morpholine and piperidine derivatives to prepare transparencies for overhead projection. Lawton, U.S. Patent No. 3,293,061 combined ninhydrin or hydrindantin with isatin-amine condensates to provide thermographic copy sheets.

Bauman and Lawton reacted ninhydrin or hydrindantin with complexes of amines and flavans or phenolic compounds to make the thermographic copy sheets, see U.S. Patent No.3,149,991 and U.S. Patent No. 3,149,992. Huffman, U.S. Patent No.

3,664,858 combined ninhydrin with the adducts of morpholine or piperidine and organic acids in thermal recording members. Sus, U.S. Patent No. 3,024,362 combined hydrindantin with amino acids or salts of primary amines with organic carboxylic and sulfonic acids to make a thermocopy paper. Allen, U.S. Patent No.

2,967,785 used the adducts of morpholine or piperidine with isatin or ninhydrin as the color forming material in thermocopy papers. Small, U.S. Patent No. 3,573,958 combined an amine with a halide or organometallic halide or germanium, silicone, lead, and tin with hydrindantin to provide a heat sensitive recording sheet. In each case the normal dye formations of Ruhrman's purple with ninhydrin, red eye with alloxan, and isatin blue were obtained.

It is often desirable and an objective of this invention to obtain colored records which have colors differing from those normally obtained with the above cyclic polyketo compounds.

Undesirable odors and fumes are obtained by the heat dissociation or decomposition of the complexes, salts, or adducts during the imaging process.

There is a problem of image bleaching during excessive heating, on aging, or prolonged exposed to ultraviolet containing light.

Other types of heat sensitive recording sheets are also well known in the art.

This invention is related to the use of a leuco or colorless form of a dye material and a phenolic material which reacts with the leuco material to form a colored dye..

There are many systems of this type represented in the patent literature.

References for these systems include: (1) Phthalides, naphthalides, fluorans Typical of these are Crystal Violet Lactone or 3,3-bis-(pdimethylaminophenyl)-6-dimethylamino phthalide and malachite green lactone or 3,3-bis(p-dimethylaminophenylphthalide). The reactions of these and many related phthalides with phenolics are described in Adachi, U.S. Patent No. 3,895,173; Schwab, U.S. Patent No. 3,322,557; Kohmura et al., U.S. Patent No. 3,859,112; Hayashi et al., U.S. Patent No. 3,773,542; Futaki et al., U.S. Patent No. 3,846,153; Baum, U.S. Patent No. 3,539,375; Shimazu, U.S. Patent No. 3,864,684; Adachi et al., U.S. Patent No. 3,843,384; Futaki et al., U.S. Patent No. 3,829,401; Futaki et al., U.S. Patent No. 3,825,432; Higachi et al, U.S. Patent No. 3,816,838; Nagashima et al., U.S. Patent No. 3,792,481; Blose et al., U.S. Patent No. 3,746,675.

Typical examples of the lactones which are listed in the patents as reacting with phenolic materials to produce a color include the following: TABLE I.

3, 3-bis(p-dimethylaminophenyl)-6-dimethylaminophthalide 3,3-bis(p-dimethylaminophenylphthalide) 3 ,3-bis [p-di(n-butylaminophenyl)phthalide] Rhodamine lactone 3- [2-methyl-4-(diethylamino)phenyl] -3-( 1 ,2-dimethyl-3-indolyl)phthalide 3 - (p - dimethylaminophenyl) - 3 - (I - ethyl - 2 - methyl - 3 - indolyl) 4,5,6,7- tetrachlorophthalide 3 ,3-bis( 1 -ethyl-2-methylindol-3-yl)phthalide 3 - (4 - morpholinophenyl) - 3 - (1,2 - dimethylindol - 3 - yl) - 4,5,6,7 - tetra chlorophthalide 3 - (1 - benzyl - 2 - methylindol - 3 - yl) - 8 - (methyl - 2 - methylindol - 3 - yl) phthalide 5-nitro-3 , 3-bis(4-dimethylaminophenyl)phthalide 5-amino-3 ,3-bis(4-dimethvlaminophenyl)phthalide 3,3-bis(p-dimethylaminophenyl)-4,5,6,74etrachlorophthalide 3 ,3-bis(p--dimethylaminophenyl)-4,5,6,7-tetrachlorophthalide 3, 3-bis(p-diethylaminophenyl)-6-dimethylaminophthalide 3 ,3-bis(p-dimethylaminophenyl)-6-aminophthalide 3,3-bis(p-dimethylaminophenyl)-6-(p-toluenesulfonamide)phthalide 3,3-bis(p-dimethylaminophenyl)-6-nitrophthalide 3 ,3-bis(p-dimethylaminophenyl)-6-monoethylaminophthalide 3 ,3-bis(p-dimethylaminophenyl)-6-chlorophthalide 3,3-bis(p-dimethylaminophenyl)-6-ethoxyphthalide 3,3-bis(p-dimethylaminophenyl)-6-diethylaminophthalide 3-(4-dimethylaminophenyl)-3-(1 ,2-dimethylindol-3-yl)naphthalide 3-(4-diethylaminophenyl)-3-(1 -phenylpyrrol-3-yl)naphthalide 3-diethylamino-7-dibenzylaminofluoran 3-diethylamino-7-(N-methylanilino)fluoran 3-dimethylamino-6-meth oxyfluoran 3-diethylamino-6-methyl-7-chlorofluoran 3-morpholino-5,6-benzofluoran 7-acetamino-3-dimethylaminofluoran 3-dimethylamino-5 ,7-dimethylfluoran 3,6-bis-p-methoxyethoxyfluoran 3 ,6-bis-P- cyanoethoxyfluoran I -amino-3 ,6 ,7-trimethylfluoran 3-dibutylamino-6-methyl-7-chlorofluoran 3-diethylamino-7-dibenzylaminofluoran 3-diethylamino-7-(N-methyl-p-toluidino)fluoran 3-dimethylamino-7-chlorofluoran 3-(diethylamino)-6-methyl-7-anilinofluoran 3,7-bis(diethylamino)fluoran 3,6-dimethoxyfluoran 3-diamylamino-6-chlorofluoran 2',6'-bis(diethylamino)fluoran 2'-(benzylamino)-6'-(diethylamino)-3',4"-benzofluoran 3-(ethyl-p-tolylamino)-7-(methylphenylamino)fluoran 3-cyclohexylamino-6-chlorofluoran 3-diethylamino-5-methyl-7-bis(4-methylbenzyl)aminofluoran 3-diethylamino-6-methyl-7-(p-butylanilino)fluoran 2'-anilino-6'-diethylamino-3 '-methylfluoran 3-(diethylamino)-7-(N-methylanilino)fluoran 2'-phenylamino-3'-methyl-6'-(N-ethyl-N-p-tolylamino)fluoran 3-diethylamino-7-piperidinofluoran 3-diethylamino-7-phenylfluoran 3-diethylamino-5-chloro-7-piperidinofluoran 3-dimethylamino-5-methyl-7-piperidinofluran 3-diethylamino-5-methyl-7-piperidinofluoran 2-(2',4'6'-trimethylphenylamino)-8 -diethylamino-3,4-benzofluoran 2,8-bis(N-ethyl-N-p-tolylamino)fluoran 3-dimethylamino-5-methyl-7-piperidinofluoran 3-(diethylamino)-6,7-dimethylfluoran 3-dimethylamino-5-methyl-7-[bis-(4-methylbenzyl)aminoifluoran 4-amino-8 [bis-P-ethoxyethyl )amino]b enzofluoran N,N'-bis(3'-diethylaminofluoran-7'yl)piperazine 2-phenylamino-6-diethylaminofluoran 2-phenylamino-6-dimethylaminofluoran 3 '-diethylamino-7 '-methylthiofluoran 3,7-bis(diethylamino)-5,6-benzofluoran 3-dimethylamino-7-benzylamino-5,6-benzofluoran 3-diethylamino-7-(N-benzyl-N-phenyl)aminofluoran 3-benzylamino-7-diethylaminofluoran 2'-(p-chloroanilino)-6'-diethylaminofluoran 2'-(m-chloroanilino)-3-methyl-6'-diethylaminofluoran 2'-(p-chloro-N-methyl anilino)-6'-diethylaminofluoran 3-(diethyl amino)-5 -methyl-7 < ,B-phenylhydrazino)fluoran 3-(diethylamino)-7-bis( 1 -naphthylmethyl)aminofluoran 3-(diethylamino)-7-(2-phthalimidino)fluoran 3-(diethylamino)-6-methyl-3'-azafluoran 3-diethylamino-5-methyl-7-(diphenylamino)fluoran 3-(dimethylamino)-7-(diphenylmethylamino)fluoran 3-(diethylamino)-6-methyl-7-(p,p'-dimethyldiphenylmethyl)amino fluoran 3-(dibutyl amino)-7-(diphenylmethylamino)fluoran 3-(diethylamino)-7-(ss,ss-dibenzyihydrazino)fluoran 3-(dimethylamino)-7-(p-methoxybenzamido)fluoran 7-anilino-3-(diethylamino)fluoran 2'-(methylphenylamino)-6'-(methyl-p-tolylamino)fluoran 2'-methyl-6'-cyclohexylamin ofluoran 2'-amino-6'-diethylamino-3'-methylfluoran 2'-amino-6'-diethylaminofluoran 2 '-(2-carboxyanilino)-6'-diethylaminofluoran 3-dibenzylamino-7-diethylaminofluoran 2'-[N-(carboethoxymethyl)amino]-6 '-diethylaminofluoran 2'-[N-(carboethoxymethyl)-N-methylamino]-6'-diethylaminofluoran Rhodamine lactam N-phenyl Rhodamine lactam Rhodamine anilino lactam 9-p-nitroamino-3,6-bis(diethylamino)-9-Xanthenoyl-6-benzoic acid lactam 9-p-nitroamino-3,6-bis(dimethylamino)-9-thioxanthenoyl-6-benzoic acid lactam (2) Spiropyrans The following are some of the patents which list typical spiropyrans giving a color when reacted with phenolic materials: Talvakar, U.S. Patent No. 3,445,261; Futaki et al, U.S. Patent No. 3,829,401; Kohmura et al., U.S. Patent No. 3,859,112 Hayashi et al, U.S. Patent No. 3,773,542; Kimura et al, U.S. Patent No. 3,666,525; Yahagi et al, Japanese Pat. No. 7363,734; Futaki et al, Germany Patent No.

2,252,845; Komura et al, German Patent No. 2,327,135; Takamizawa et al, Japanese Patent No. 74--00,069; Robillard et al, French Patent No. 2,204,151; Haino et al, Japanese Patent No, 75-01,746; Samat et al, German Patent No.

2,522,877; Miyazawa et al, Japanese 75-137,146; Takimoto et al, Japanese Patent No. 75-152,742; Futaki et al, German Patent No. 2,252,845; Miyazawa et al, Japanese Patent No. 75-137,549.

Typical examples of the spiropyrans listed in the patents as reacting with phenolic materials to yield colored dyes include: TABLE II.

6'-chloro-8 '-methoxybenzoindolinospiropyran benzothiazolinospiropyran benzo-p-naphthospiropyran 3-methyl-di-ss-naphthospiropyran 1,3,3-trimethyl-6'-chloro-8'-methoxyindolinobenzospiropyran 6-chloro-8'-methoxyindolinobenzospiropyran 6-chloro-8-methoxy-1 ',3',3'-trimethylspiro( l-benzopyran-2,2'-indoline) spiro (I-benzopyran-2,2'-naphthopyran) 8 '-methoxybenzoindolinospiropyran 1,3,3-trimethyl-4,7,8'-trimethoxy [(2'H-1'-benzopyran)-2,2'-indoline] 6-chloro-8'-methyl-1,3,3-trimethylbenzoindolinospiropyran 2-ethyl-3,3'-spirobinaphthopyran 3-phenyl-di-p-naphthospiropyran di-,1-naphthospiropyran 3-ethyl-di-p-naphthospiropyran 3,3'-dichlorospirodinaphthopyran 1,3,3-trimethyl-6'-nitrospiro(2'H-1'-benzopyran-2,2'-indoline) 1,3,3-trimethyl-8'-nitrospiro(2'H-1'-benzopyran-2,2'-indoline) 1,3,3-trimethyl-6'-nitro-8'-methoxyspiro(2'H-1'-benzopyran-2,2'-indoline) 1,3,3-trimethyl-5 '-nitro-8 '-methoxyspiro(2'H- 1 '-benzopyran-2,2'indoline) 3,7-bis(3',6'-dimethoxy-9'-spiroxanthyl)pyromellitide Typical examples of phenolic materials listed in the patent literature as reacting with the leuco compounds such as the phthalides, naphthalides, fluorans, and spiropyrans to form colored dyes include: TABLE III.

4,4'-isopropylidene diphenol 4,4'-isopropylidene-bis(2-methylphenol) 4,4'-isopropylidene-bis(2-phenylphenol) 4,4'-isopropylidene-bis(2-t.butylphenol) 4,4'-sec.butylidene-diphenol 4,4'-sec.butylidene-bis(2-methylphenol) 4,4'-cyclohexylidene-diphenol 4,4'-cyclohexylidene-bis(2-isopropylphenol) 4,4'-ethylidene-diphenol 2,2'-methylidene-bis(5-methylphenol) 4,4'-ethylidene-bis(2-methylphenol) 4,4'-(1 -methylpentylidene)diphenol 4,4'-(methylisopentylidene)diphenol 4,4'-( 1 -methylhexylidene)diphenol 4,4'-(1 -ethylbutylidene)diphenol 4,4'-(ethylpropylidene)-bis(2-methylphenol) 4.4'-isopropylidenedicatechol 4,4'-benzylidene-diphenol 4,4'-isopropylidene-bis(2-chlorophenol) 2,2'-dihydroxydiphenyl 2,2'-methylene-bis(4-chlorophenol) 2,2'-methylene-bis(4-methyl-6-t.butylphenol) 4,4'-isopropylidene-bis(2,6-dimethylphenol) 2,2'-thiobis(4,6-dimethylphenol) 4,4'-ethylene diphenol 4,4'-( 1 -methylbenzylidene)diphenol 4-t.butylphenol 4-phenylphenol -naphthol TABLE III - cont.

p-naphthol hydroquinone pyrocatechol pyrogallol phloroglucine m.cresol There are a number of commercial products which use the above-described combinations of leuco dyes and phenolic derivatives. These have found applications in thermal copying paper using thermal copiers. Thermally responsive sheets using these materials have also been used with computer-driven thermal printers. Sensitized papers containing a combination of leuco dyes and phenolic materials are used in chart recording instruments wherein a colored trace record is obtained by contacting the paper with a hot pen or stylus. There are certain inherent disadvantages found with the leuco dye-phenolic combinations.

Complaints are received on background staining, fading of the record mark, flooding of the image, moisture sensitivity, odor, pressure sensitivity causing accidental marking by paper clips and the like, railroading, and burnout on chart recording papers. Many of the phenolic materials described in the patents are toxic or irritating and cannot be used. These same leuco dye-phenolic color-forming systems are used in the "carbonless" pressure marking papers and the reactants are kept separate by microencapsulation or by being contained in separate layers.

Pressure contact of these materials results in dye formation. This property is also inherent in the thermal papers and excess pressure will cause accidental marking.

Also, for this same reason, the reactants must be ground separately and a solvent or resin binder-solvent combination which will dissolve or partially dissolve one or both of the co-reactants will result in premature dye formation in the coating mix.

The object of this invention is to eliminate or minimize the problems in cured with the leuco dye-phenolic thermal color reacting systems. Another objective is to minimize the sublimation or migration of the phenolic material which has caused problems with staining and change in sensitivity. Still another objective is the manufacture of thermal record sheets with improved image sharpness and definition.

I have found that the problems and disadvantages of the above described thermal recording systems can be minimized or eliminated by using a combination of leuco dye precursors of the lactone or spiropyran types with cyclic polyketo compounds such as ninhydrin, hydrindantin, isatin, alloxan, and their homologs. I have found that the color precursors may be chemically combined as adducts or chemical complexes of one another which are light in color but can be converted by heat to a dark colored dye. The dye thus formed is not typical of either of the coreacting color precursors but rather produces a color additive effect approaching the black dyes most desired for imaging purposes. I have further found that a similar additive effect is obtained when the individual color precursors are mixed together and heated.Presumably, the precursors go through the adduct or complex forming process during fusion and are converted to the final dye by further heating.

I have further discovered that molecular complexes of phenolic compounds with amines or amides can be added to the mixtures or adducts of the combined precursors resulting in an increase in dye intensity of the image and also providing faster thermal response at lower temperatures during the imaging process. I have further discovered that certain additives may be used with the color precursor adducts or complexes, mixtures of the color precursors, or a combination of these with molecular complexes of phenolics and amines to further increase the color intensity of the image and also increase the rate of thermal response during imaging.

Materials a. Lactones Crystal Violet lactone (3 ,3-bis-(p-dimethylaminophenyl)-6-dimethylamino- phthalide, Malachite Green lactone (3,3-bis(p-dimethylaminophenyl)phthalide), and 3,3-bis(l-ethyl-2-methylindol-3-yl) phthalide were obtained from the Hilton-Davis Co., Cincinnati, Ohio. The 3,3-bis(p-aminophenyl)phthalide was obtained from the Organic Chemicals Div., Eastman Kodak Co., Rochester, NY.

b. Spiropyrans The indolinospiropyrans were prepared in the normal manner by well known methods described in the art by refluxing equimolar amounts of the desired Fischer's base, in these examples 1,3,3-trimethyl-2-methylene indoline or the 5 chloro derivative of the same with the desired aldehyde, e.g., salicylaldehyde, 5 nitrosalicylaldehyde, 5-bromo-salicylaldehyde, 3,5-dibromosalicylaldehyde, and o vanillin in absolute alcohol for three to four hours, cooling, filtering, and washing the precipitate with alcohol and drying. Similarly, 2-methylbenzothiazolium methyl tosylate was reacted with 2-hydroxy-l-naphthaldehyde and with salicylaldehyde to give the corresponding spiropyrans.The 3-methyl-di-p-naphthospiropyran was obtained in the usual manner by treating 2-hydroxy- I-naphthaldehyde and methylethyl ketone in absolute ethanol with hydrogen chloride gas and neutralizing the salt formed with sodium carbonate and recrystallizing the product from benzene.

c. Adducts or complexes of lactones or spiropyrans with cyclic ketones including ninhydrin and isatin These were prepared by boiling with stirring for thirty minutes a mixture of 15 parts of lactone or spiropyran and 15 parts of ninhydrin or isatin in 250 parts anhydrous denatured alcohol. The hot mother liquor was decanted from the residue, chilled in a cold box to crystallize and precipitate the adduct, and the precipitated adduct was washed with alcohol and air dried.

d. Complexes The phenolic material is dissolved in anhydrous methanol or ethanol to form a 25 percent solution. The hydrogen bonding co-reactant amine or amide is added to the alcoholic solution of the phenolic derivative in molecular equivalents corresponding to the number of functional hydroxyl groups in the phenolic compound. For example, two moles of cyclohexylamine are added to one mole of a bisphenol, one mole of amine is added to one mole of a mono-hydroxy compound, etc. The mixtures are stirred for a few minutes until they become homogeneous. In some cases, a solid complex will form and precipitate almost immediately, while others must be chilled in a cold box before solid products are obtained. The mixture containing the precipitated complex is then filtered and the precipitate is washed with alcohol and allowed to dry. The following table contains a number of hydrogen-bonded phenolic complexes which have been prepared in this manner.

TABLE IV - AROMATIC HYDROXY COMPLEXES Dissociation Phenol Amine/Amide Temp."C p,p' biphenol ethylene diamine 136-140 t.butyl amino ethyl methacrylate Bisphenol B ethylenediamine 85-92 formamide 64-66 t.butyl aminoethyl methacrylate 946 4,4'-isopropylidene bis (2-isopropylphenol) triethanolamine 6063 ethylene diamine 100 4 TABLE IV cont.

Dissociation Phenol Amine/Amide Temp 4,4'-isopropylidene bis (2,6-dibromophenol) diethanol amine 107-145 triethanolamine 128-157 " ethylene diamine 198-215 " diethylenetriamine 210-215 " propylene diamine 146-156 " formamide 95-102 hydrazine 135-150 t.-butyl aminoethyl methacrylate 130-5 4-hydroxy propiophenone hydrazine 8W90 2,4-dichloro-6-phenylphenol ethylenediamine 100-4 diethylenetriamine 115-20 " propylenediamine 92-4 2,2'-methylenebis (3,4,6-trichlorophenol) diethanolamine 75-8 " triethanolamine 118-23 " ethylenediamine 124-7 " diethylenetriamine 90-110 " propylene diamine 125-30 formamide 125-30 hydrazine 1804 t-butylamine ethyl methacrylate 123-6 2-bromo-4-phenyl phenol ethylenediamine 66-8 " diethylene triamine 78-82 " formamide 55-8 p-phenyl phenol ethylene diamine 137-43 " diethylene triamine 99-104 " propylene diamine 77-81 " formamide 90-5 hydrazine 145-150 TABLE IV - cont.

Dissociation Phenol Amine/Amide Temp. C 2,2'-thiobis (4,6-dichlorophenol) triethanolamine 120-5 ethylene diamine 125-130 " diethylene triamine 158-164 " propylene diamine 142-5 formamide 115-25 hydrazine 195-200 4,4'-isopropylidenebis (2,6-dichlorophenol) ethylenediamine 192-5 " diethylene triamine 210-15 " propylene diamine 170-5 " formamide 100-5 " hydrazine 142-6 4,4'-isopropylidenebis (2,6-dichlorophenol) t.butyl amine ethyl methacrylate 132-5 5-chloro-2-hydroxy benzophenone ethylene diamine 1904 o-phenylphenol ethylene diamine 55-60 " formamide 50-3 hydrazine 60--4 Dichlorophene formamide 90-3 2,2'-methylenebis (4-ethyl-6-t,butylphenol) triethanolamine 68-70 Bisphenol A ethylene diamine 1004 " propylene diamine 94-100 " t.butylamine ethyl methacrylate 4,4'-thiobis (6-t.butyl-m-cresol) triethanolamine 95-8 " ethylene diamine 106-11 propylene diamine 125-35 t.butylamine ethyl methacrylate 62-5 TABLE IV - cont.

Dissociation Phenol Amine/Amide Temp. C 4,4'-butylidenebis (6-t.butyl-m-cresol) triethanolamine 68-70 2,2'-methylenebis (4-methyl-6-t.butylphenol) diethanolamine 62-5 " ethylene diamine 54-8 p-cyclohexyl phenol triethanolamine 35-10 ethylene diamine 125-30 " diethylene triamine 70-85 " propylene diamine 88-90 o-cyclohexyl phenol ethylene diamine 88-93 " hydrazine 75-80 p-t.butyl phenol ethylene diamine 70-3 " propylene diamine 54-7 p.-sec.butyl phenol ethylene diamine 50-4 p-bromophenol formamide 35-8 2,4,6-tribromophenol ethylenediamine 135-8 " propylenediamine 85-9 " formamide 90-3 pentachlorophenol diethanolamine 145-55 " triethanolamine 133-7 ethylenediamine 115-20 diethylenetriamine 185-90 " propylene diamine 168-72 " formamide 100-5 " hydrazine 200-5 t.butyl amine ethyl methacrylate 115-20 2,6-dichlorophenol triethanolamine 83-6 " ethylene diamine 110-15 " propylenediamine 100-155 " formamide 40-5 TABLE IV - cont.

Dissociation Phenol Amine/Amide Temp. C 2,6-dichlorophenol hydrazine 115-20 " t.butyl amine ethyl methacrylate 100-5 2-chloro-4-phenyl phenol ethylene diamine 130-5 " propylene diamine 50-4 " hydrazine 108-12 tetrachlorophenol diethanolamine 110-25 " diethanolamine 98-104 " ethylene diamine 165-70 " formamide 85-90 " hydrazine 163-5 " t.butylamino ethyl methacrylate 95-100 2,4,6-trichlorophenol ethylene diamine 105-14 propylene diamine 100-5 formamide 85-90 hydrazine 150-7 " t.butyl amine ethyl methacrylate 70-5 p-p-ethylenediimino-o cresol formamide 105-10 " 5.butylamine ethyl methacrylate 118-12 Bisphenol A benzylamine 70-4 4,4'-isopropylidenebis (2,6-dibromophenol) 2-amino-1-butanol 155-62 " aminoethylenethanolamine 74-85 " 2-amino-2-ethyl-1, @ @@@@@@@@@@@ 1@@ @@ 3-propenediol 130-40 " 2-amino-2-methyl-1, 3-propenediol 154-60 " aminoethyl piperazine 140-50 2-amino-2-methyl- 1 propanol 180-90 " 2-amino-1-phenyl-1 propanol 100-30 TABLE IV - cont.

Dissociation Phenol Amine/Amide Temp. C 4,4-isopropylidenebis 3-amino propanol 190-5 (2,6-dibromophenol) " benzylamine 144-8 " chloroacetamide 114-22 " 3-chloro-N-methyl acetamide 80-5 n-decylamine 170-90 " 1,3-diamino propane 218-225 " 3-di-n-butyl amino propylamine 150-8 diethanolamine 140-3 " diethylamino ethoxy ethanol 180-5 " diethylamino propylamine 175-85 " N-diethyl amino propyl-1 methyloctadecylamine 88-100 " diethylisopropanolamine 135-42 4,4'-isopropylidenebis (2,6-dibromophenol) diispropanolamine 65-75 " diisopropylethanolamine 158-165 " dimethylacetamine 95-100 " dimethylamino propylamine 198-202 " dimethylethanolamine 135-45 " dimethylformamide 60-5 " N-(1,1-dimethyl-2-hydroxy ethyl)-2-methyl1-1,2 Propane diamine 130-40 " t.-dodecylaminopropylamine 90-105 ethanolamine 17080 " N-ethylethanolamine 90-100 " N-ethyldiethanolamine 137-42 hexamethyl phosphoramide 127-30 " n-hexylamine 200-10 " triamine hydroxyethyl diethylene 60-80 TABLE IV - cont.

Dissociation Pneno@ Am@e/Amide lemp. C 4,4-isopropylidenebis N-2-hydroxyethyl-1 (2,6-dibromophenol) methyl dodecylamine 100-110 N-hydroxyethyl piperazine hydroxy ethyl trihydroxy propyl-ethylene diamine 45-55 " iminobispropylamine 210-20 " isobutylamine 160-70 " isopropylamine 165-75 " 3-isopropoxypropanolamine 165-75 " isopropylamine 160-70 " methanediamine 140-5 " methyldiethanolamine 132-6 methyl ethanol amine 143-6 N-methyl-bis-amino propylamine 210-20 " polyglycol amine H-119 115-20 " polyglycolamine H-176 195-205 " polyglycolamine H-221 165-174 " 1,2-propanediamine 150-160 " propylenediamine 148-155 " tetramethylethylenediamine 190-200 " tetramethylguanidine 225-235 " triethanolamine 154-8 " triethylene tetramine 200-15 " triisopropanolamine 135-9 p,p'-biphenol hexamethyl phosphoramide 40-50 4-hydroxy propiophenone hydrazine 84-90 2,2'-methylene bis (2,4,6-trichlorophenol) aminoethylethanolamine 165-7 " 2-amino-2-ethyl-1,3 @@@@@@@@@@@ @@@ @@ propanediol 151-70 2-amino-2-methyl-1,3 propanediol 1824 " benzylamine 210-16 TABLE IV - cont.

Dissociation Phenol Amine/Amide Temp. C 2,2'-methylene bis t.butylaminoethyl (2,4,6-trichlorophenol) methacrylate 123-6 " diethanolamine 75-8 " diethylenetriamine 90-110 2,2'-methylene bis (2,4,6 trichlorophenol) dimethylethanolamine 183-93 " N-ethyldiethanolamine 124-7 " ethylene diamine 187-92 " formaminde 125-30 " hexamethylphosphoramide 85-90 hydrazine 180-4 " N-methylbisamino propylamine 157-65 " methyldiethanolamine 154-7 2,2'-methylene bis (2,4,6 trichlorophenol) methylethanolamine 193-200 " polyplycolamine H-176 208-24 propylenediamine 135-40 " triethanolamine 142-6 2,4-dichloro-6-phenyl phenol diethylene triamine 115-20 " ethylene diamine 100-4 propylenediamine 92-1 2-bromo-4-phenyl phenol benzylamine 85-95 " diethylenetriamine 78-82 " ethylenediamine 66-8 " formamide 55-8 " hydrazine 82-8 p-phenyl phenol benzylamine 70 " diethlenetriamine 99-104 " ethylenediamine 137-40 " formamide 113-5 TABLE IV - cont.

Dissociation @@@@@@ A@@@/A@@de @emp. C p-phenyl phenol hexamethyl phosphoramide 34-5 " hydrazine 155-8 " propylene diamine 71-81 " triethylene tetramine 63-5 2,2'-thiobis (4,6 dichlorophenol 2-amino-2-ethyl-1, 3-propanediol 125-59 " benzylamine 197-9 " diethanolamine 143-7 " diethylene triamine 158-74 " diiosopropanolamine 155-62 " dimethylacetamide 190-3 " dimethylethanol amine 120-3 " N-ethyldiethanolamine 127-30 ethylene diamine 125-30 hydrazine 195-200 " iminobispropylamine 50-74 " methyldiethanolamine 127-40 " polyglycolamine 210-14 " propylene diamine 142-5 formamide 115-25 " triethanolamine 165-8 " triisopropanolamine 151-5 2,2' methylene bis (4 chlorophenol) benzylamine 60-100 2,2' methylene bis (4 chlorophenol) formamide 90-3 4,4'-isopropylidene bis (2,6-dichlorophenol) 2-amino-1-butanol 166-70 " aminoethylethanolamine 154-8 " 2-amino-2-ethyl-1,2 propanediol 166-8 TABLE IV - cont.

Dissociation Phenol Amine/Amide Temp. C 4,45 -i opropylidene bis 2-amino-2-methyl-1,3 (2,6-dichlorophenol) propanediol 172-5 " 3-amino propanol 180-90 " amylamine 200-10 " aniline 90-6 " benzylamine 145-55 " t.butylaminoethyl methacrylate 132-5 " cyclohexylamine 190-204 " n-decylamine 193-8 " 1,3-diamino propane 230-5 " dibutylamine 124-57 " 3-di-n-butylamine propylamine 155-64 " dibutylmethylamine 120-31 " dicyclohexylamine 202-6 " diethanolamine 150-3 " diethylamine 142-7 " diethylaminoethyl methacrylate 115-7 " ss-diethylaminopropionitrile 94-6 " 3-ethylamino propionitrile 103-5 " di-2-ethylhexylamine 100-5 " diethylene triamine 210-15 " diethylisopropanolamine 125-35 " diisopropylethanolamine 162-4 " diisopropylamine 141-52 " ss-dimethylamino propionitrile 70-30 " dimethylaminopropylamine 197-203 " dimethylethanolamine 140-6 " di-n-propylamine 142-53 " 3-t.-dodecylaminopropylamine 100-5 TABLE IV - cont.

Dissociation Phenol Amine/Amide Temp. C 4,4'-isopropylidene bis (2,6-dichiorophenol) ethanolamine 96-104 " N-ethylcyclohexylamine 161-78 " N-ethyldiethanolamine 154-5 " ethylene diamine 208-10 " N-ethylethanolamine 87-110 formamide 103-8 " hexamethylphosphoramide 122-4 " n-hexylamine 168-85 " hydrazine 142-6 " hydroxyethylethylethylene diamine " iminobispropylamine 220-3 " isobutylamine 152-67 " isodecylamine 187-95 " isooctylamine 172-84 isopropanolamine 150-7 3-isoprop oxyisopropanol amine 160-7 " ss-isopropylaminopropion itrile 103-7 " 3-isopropylamine propylamine 122-7 " isoquinoline 102-4 " 2,6-lutidine 125-32 " methanediamine 186-90 " N-methyl bis amino propylamine 219-36 " methylaminopropylamine 207-13 " methylbenzylamine 145-55 " N-methyldiethanolamine 148-52 " N-methylethanolamine 85-102 " 3,3'-methyl iminobis propylamine 190-9 TABLE IV - cont.

Dissociation Phenol Amine/Amide Temp. .C 4,4,-isopropylidene bis (2,6-dichlorophenol) N-methyl morpholine 1204 N-methyl-2-pyrrolidone 70-3 morpholine 159-60 " phenyldiethanolamine 85-95 " phenylethanolamine 88-95 " 2,2'-phenyliminodiethanol amine 55-70 " &gamma;;-picoline 96-9 " polyglycolamine H-119 156-63 " polyglycolamine H-169 123-33 " polyglycolamine H-176 210-18 " polyglycolamine H-221 196-200 propylenediamine 168-75 " pyridine 117-30 " tetraethylene pentamine 92-102 " tributylamine 103-8 " triethylamine 155-64 " triethanolamine 139-45 " triethylene tetramine 215-20 " triisopropanolamine 125-30 " trimethylenediamine 230-5 " dimethylacetamide 132 5-chloro-2-hydroxy benzo phenone ethylenediamine 1904 2,2'-methylene bis (4-ethyl 6-dibutyl phenol) benzylamine 76-85 " triethanolamine 68-70 o-phenyl phenol ethylenediamine 55-60 " formamide 50-3 " hydrazine 60-4 4,4'-isopropylidene bis phenol benzylamine 80-90 TABLE IV - cont.

Dissociation Phenol Amine/Amide Temp. C 4,4'-isopropylidene bis- t.butylaminoethyl phenol methacrylate 90-2 cyclohexylamine 108-10 dibutylamine 120-52 diethylamine 117-53 dimethylamine 105-8 propylamine di-n-propylamine 90-100 ethylenediamine 1004 " formamide 66-8 " isobutylamine 88-93 " methanediamine 128-30 " N-methyliminobis propylamine 94-8 " propylenediamine 95-100 " triethylenetetramine 137-9 4,4'-thiobis (6-t.butyl m-cresol) t.butylamino ethyl methacrylate 62-5 " cyclohexylamine 78-85 ethylenediamine 112-15 " iminobispropylamine 85-95 " isopropylamine 164-6 " proylenediamine 130-6 " pyridine 160-5 " triethanolamine 95-8 4,4'-butylidene bis (m-cresol) acetamine 82-3 benzylamine 135 cyclohexylamine 214-7 " ethylenediamine 213-7 " tridethanolamine 68-70 TABLE IV - cont.

Dissociation Phenol Amine/Amide Temp. C 2,2'-methylene bis(4 methyl-6-t.butylphenol) 2-amino-1-butanol 58-64 " benzylamine 69-79 " decylamine 52-3 " 1,3-diaminopropane 50-5 " N-dibutylethylamine 60-5 " diethanolamine 62-5 " di-n-hexylamine 81-9 " ethylcyclohexylamine 92-4 " N-ethyl diethanolamine 68-71 isopropylaminoiso propylamine 128-32 " ethylene diamine 54-8 " hexamethyl phosphoramide 58-65 " isoquinoline 121-5 " N-methyldiethanolamine 127-34 " methyl ethanolamine 73-84 " triamylamine 65-75 " triethanolamine 61-5 p-cyclohexyl phenol triethanolamine 35-40 " benzylamine 50-5 " diethylenetriamine 70-85 " ethylene diamine 125-30 " hexamethyl phosphoramide 97-109 hydrazine 115-20 " propylene diamine 88-90 o-cyclohexyl phenol benzylamine 82-95 " ethylene diamine 88-93 " hydrazine 75-80 p.t-butyl phenol benzylamine 70-80 " ethylenediamine 70-3 TABLE IV - cont.

Dissociation Phenol Amine/Amide Temp. C p.t-butyl phenyl hydrazine 45-50 " proylenediamine 54-6 p-bromophenol formamide 35-8 2,4-dibromophenol benzylamine 80-5 2,4,6-tribromophenol t.butyl amino ethyl " methacrylate 68-71 " benzylamine 125-30 " ethylene diamine 135-8 " formamide 90-3 hydrazine 145-54 " propylene diamine 87-92 Pentachlorophenol benzylamine 155-60 t.-butylaminoethyl methacrylate 115-20 diethanolamine 145-55 " diethylenetriamine 185-90 ethylenediamine 115-20 formamide 100-105 " hexamethyl phosphoramide 79-83 hydrazine 200-205 propylenediamine 168-72 " triethanolamine 133-7 2,6-dichlorophenol benzylamine 100-5 t.butylaminoethyl methacrylate 100-5 diethanolamine 836 " ethylenediamine 110-15 formamide 40-6 hydrazine 115-20 propylenediamine 115-25 2-chloro-4-phenyl phenol benzylamine 95-100 " ethylenediamine 130-5 TABLE IV - cont.

Dissociation 2-chloro-4-phenyl phenol hydrazine 108-12 propylenediamine 50-4 tetrachlorophenol benzylamine 115-25 " t.butylaminoethyl methacrylate 95-100 " diethanolamine 110-25 ethylenediamine 192-5 " formamide 85-90 hydrazine 163-5 " propylenediamine 165-70 " triethanolamine 98-104 2,4,6-trichlorophenol benzylamine 120-5 " t.butylaminoethyl methacrylate 70-5 ethylenediamine 105-14 " formamide 85-90 hydrazine 150-7 " propylenediamine 100-5 2,4-dichloro-1-naphthol benzylamine 55-60 " diethanolamine 65-70 2,4-dichloro-1-naphthol diethylenetriamine 79-83 " formamide 78-82 " hydrazine 83-93 2-naphthol triethanolamine 63-5 " benzylamine 40-5 " ethylenediamine 86-9 " formamide 56-59 " hydrazine 110-12 4,4-isopropylidene bis (p-chlorophenol) benzylamine 105-10 " formamide 55-60 TABLE IV - cont.

Dissociation Phenol Amine/Amide Temp. C " hexamethyl phosphoramide 46-8 hydrazine 100-112 2,6-dibromo-t.butyl phenol benzylamine 75-80 2,6-dibromo-t.butyl phenol diethylenetriamine 85-96 " ethylenediamine 95-105 hydrazine 105-110 " propylenediamine 95-100 triethanolamine 104-6 p-phenoxy phenol ethylenediamine 5662 " hydrazine 48-56 2,4,5-trichlorophenol benezylamine 118-20 " t.butylaminoethyl methacrylate 55-60 diethanolamine 105-10 " diethylenetriamine 85-95 " ethylenediamine 55-60 " hydrazine 94-100 propylenediamine 96-104 1, 1-di (4-hydroxyphenyl) cyclohexane diethanolamine 100-112 propylenediamine 120-5 1,1-di(3,5-dibromo-4 hydroxy phenyl) cyclohexane diethanolamine 149-54 propylenediamine 175-80 3,3-bis(3,5-dibromo-4 hydroxy phenyl) pentane propylenediamine 183-92 2,2-bis(3,5-dibromo-4 hydroxy phenyl)pentane diethanolamine 110-18 propylenediamine 180-90 bis (3,5-dibromo-4 hydroxy phenyl) methane diethanolamine 115-23 2,2-bis (3,5-dibromo4- hydroxy phenyl) butane diethanolamine 142-5 " propylenediamine 174-6 TABLE IV - cont.

Dissociation Phenol Amine/Amide Temp. C 3,3'-5,5'-tetrabromo-4,4' dihydroxy biphenyl diethanolamine 173-80 1-phenyl-1, 1-di (3,5-di- bromo-4-hydroxy phenyl) ethane diethanolamine 145-50 " propylenediamine 185-200 2,2-di (3,5-dibromo-4 hydroxyphenyl)4-methyl pentane diethanolamine 115-20 propylenediamine 190-4 2,2-di (3,5 dibromo-4 hydroxy phenyl) heptane diethanolamine 145-50 propylenediamine 195-7 1,1-di(3,5-dibromo-4 hydroxy phenyl) butane diethanolamine 100-15 " propylene diamine 173-7 2,2-di (3,5-dibromo-4 hydroxy phenyl) octane diethanolamine 140-2 1,1-di(3,5-dibromo-4 hydroxy phenyl)ethane diethanolamine 105-10 " propylenediamine 175-8 2,4-dihydroxybenzophenone propylenediamine 212-18 3,5-dichlorosalicylaldehyde diethanolamine 100-5 " hexamethyl phosphoramide 70-84 " propylenediamine 135-45 bisphenol A disalicylate diethanolamine 150-5 propylenediamine 155-75 tetrachlorohydroquinone diethanolamine 146-50 " propylene diamine 175-80 2-hydroxy-5-phenyl propiophenone propylenediamine 180-5 2,4,6-tribenzoyl resorcinol diethanolamine 125-30 propylenediamine over 280 3,5-dibromosalicylaldehyde diethanolamine 90-8 " hexamethylphosphoramide 83-95 propylenediamine 150-2 TABLE IV - cont.

Dissociation Phenol Amine/Amide Temp. C 2-isopropyl-4,6-dinitro phenol diethanolamine 105-10 propylenediamine 188-90 3 ,4,6-trichloro-2-nitro phenol diethanolamine 146-50 propylenediamine 185-90 1,1-methylenebis-2-naphthol diethanolamine 135-40 " hexamethylphosphoramide 142-4 " propylenediamine 160-5 1,1-di-2-naphthol diethanolamine 158-74 " hexamethylphosphoramide 112-20 " propylenediamine 120-30 I,l-thio bis (2-naphthol) diethanolamine 135-42 " hexamethyl phosphoramide 124-8 propylenediamine 120-5 p-chlorotrisphenol diethylene triamine 132-8 " hexamethylphosphoramide 149-51 l,l-bis (3,5-dichloro-4 hydroxyphenyl)cyclohexane benzylamine 144-52 1,1-bis(3,5-dichloro-4 hydroxy phenyl)cyclohexane diethanolamine 140-3 " diisopropyl-ethanolamine 164-8 " dimethyl ethanolamine 169-85 " methyl diethanolamine 131-9 " methyl ethanolamine 165-71 " polyglycolamine H-176 192-200 pentabromophenol aminoethylethanolamine 131-3 " 2-amino-2-methyl-1,3 propanediol 170-9 " benzylamine 155-8 diethanolamine 15861 " diisopropanolamine 178-37 TABLE IV - cont.

Dissociation Phenol Amine/Amide Temp."C pentabromophenol - diisopropyfethanolamine 130-3 " N-ethyldiethanolamine 93-8 methyl diethanolamine 120-3 methyl ethanolamine 163-5 triethanolamine 129-34 hydroquinone acetamide 99105 formamide 63-5 morpholine 64-8 piperazine 187-95 resorcinol hydrazine 48-55 piperazine 147-52 pyrogallol formamide 55-8 acetamide 5865 e. Substrates The substrates used were a 25 lb/3000 sq. ft. bleached sulfite paper and 3 mil polyester film.

f. Test equipment A thermal copier was used for reproduction and also for preparation of transparencies. A thermal matrix printer was used to demonstrate printing. A recorder was used to demonstrate chart recording capabilities.

The preferred embodiment of the invention is the use of a combination of color formers with a molecular complex of an amine and a phenolic compound and optionally an accelerator. Stabilizers may also be used if so desired.

Preparation of Coatings The phenolic hydrogen bonded complexes are dispersed in a solution of a binder and ball-milled or otherwise ground until a fine particle size, preferably below 10 microns, is obtained. Any solvent-binder system may be used which does not dissolve and dissociate the phenolic complex. Some suitable systems include water solutions of polyvinyl alcohol, hydroxyethyl cellulose, and other common water-soluble polymeric resins. Methanol or ethanol solutions of nitrocellulose, eth lcellulose, and other alcohol-soluble resins can be used. Likewise, hydrocarbon solutions of styrene polymers or copolymers, acrylate or methacrylate polymers or copolymers, hydrocarbon resins, elastomeric polymers, and the like, can be used.The limits for the concentration are governed by desirable coating viscosities, dry weight of the coating, and the like. Concentrations of complexes varying between 5 and 50 percent have been found to be convenient.

Similarly, the leuco dye color-forming material is also dispersed by ball-milling or by other convenient means in a solvent-binder system which will not dissolve and dissociate the phenolic molecular complex. The reactive ingredients are ground separately in this case to permit the more convenient variation of the ratios of the co-reacting leuco dyes and phenolic complexes. However, this is not a requirement as the leuco dyes and phenolic complexes have been ground together without encountering any signs of mix instability or loss of the marking characteristics of the dried coating. This is not true when the leuco dye, for example Crystal Violet Lactone, is ground with the free phenolic material. The ground mixture becomes highly colored and is useless as a coating material.

Coating Applications The mixtures of grinds of the leuco dyes and molecular complexes of phenolic materials were applied by Meyer rod to a 25 lb/3000 sq. ft. sulfite base paper and allowed to air-dry. Dry coating weights of the thermosensitive coatings were varied from 1.5 lb/3000 sq. ft. to over 10 lb/3000 sq. ft. and useful records were made with each coating.

Specific Examples The ingredients are individually dispersed by ball-milling as a 15 percent concentration in a 5 percent solution of polyvinyl alcohol in water. These are combined in the ratios indicated in the table and coated onto the substrate with a No. 16 wire wound Meyer rod and air dried. The coated substrates were imaged in the test equipment to give the color indicated in the table.

COLOR PRECURSORS Spyropyrans Code Base Aldehyde A 2-methylbenzothiazolium methyl tosylate 2-hydroxyl- 1 -naphthaldehyde B ,, " " salicylaldehyde C 5-chloro-2-methylene-1,3,3-trimethyl indoline salicylaldehyde D " 5-nitrosalicylaldehyde E " 5-bromosalicylaldehyde F 3 ,5-dibromosalicylaldehyde G 2-methylene-1,3,3-trimethylindoline 5-nitrosalicylaldehyde H " o-vanillin I 3-methyl-di-p-naphthospiropyran Lactones J Crystal Violet lactone K 3,3-bis-p-aminophenylphthalide L 3,3-bis(1-ethyl-2-methylindol-3-yl)phthalide M Malachite Green lactone Cyclic Polyketones I Ninhydrin II Hydrindantin III Isatin IV Alloxan IMAGED SHEETS Lactone or Cyclic Other Coating Wt. Trace Spiropyran Polyketone Phenolic Complex Additives Ratios lb/3000 sq ft Color J II - 4-phenylpiperidine 2/4/2 3.3 black J II - - 1/2 2.5 bluegray J II hexachlorophene/ cyclohexylamine - 2/3/2 4.0 v. dark bluegray J II - p-toluic acid 4phenylpiperidine 2/4/1/2 3.2 greenblack J II hexachlorophene/ dimethylethanolamine - 1/2/2 3.5 black J II 2,2'-thiobis(4,6-dichlorophenol)/ cyclohexylamine - 1/2/2 3.1 black J II - piperazine/ terephthaldehyde 1/2/1 4.3 black J II 2,2'-thiobis(4,6-dichlorophenol)/ cyclohexylamine - 1/1/2 3.0 black IMAGED SHEETS - cont.

Lactone or Cyclic Other Coating Wt. Trace Spiropyran Polyketone Phenolic Complex Additives Ratios lb/3000 sq ft Color J II 2,2'-thiobis(4,6-dichlorophenol)/ diethanolamine - 1/2/2 2.0 slate blue K II 2,2'-thiobis(4,6-dichlorophenol)/ ethanolamine - 1/2/2 1.0 black K II - - 1/2 2.2 dark gray J III - - 1/2 1.8 bluegreen J IV - - 1/2 2.3 dark redbrown J II 1,1-bi-2-naphthol/ cyclohexylamine - 1/2/2 3.7 black J II " - 2/1/1 3.0 black J II " - 1/2/1 2.7 black J II " - 1/1/1 3.6 black J II " - 2/1/2 3.3 black IMAGED SHEETS -cont.

Lactone or Cyclic Other Coating Wt. Trace Spiropyran Polyketone Phenolic Complex Additives Ratios lb/3000 sq ft Color J II dichlorohydroquinone/ cyclohexylamine - 2/2/1 4.5 black J II " - 1/2/1 5.0 blueblack J II " - 1/2/2 3.6 blueblack J II 2,2'-thiobis(4,6-dichlorophenol)/ diethanolamine - 1/2/2 1.9 bluegray J II hexachlorophene/ cyclobexylamine sulfanilamide 1/3/1/2 4.3 black J II - sulfanilamide 1/3/2 3.8 black J II - 4,4'-dithiodimorpholine 1/3/2 4.0 black J II - N-cyclohexyl-2benzothiazolesulfenamide 1/2/2 4.4 black IMAGED SHEETS - cont.

Lactone or Cyclic Other Coating Wt. Trace Spiropyran Polyketone Phenolic Complex Additives Ratios lb/3000 sq ft Color J II hexachlorophene/ cyclohexylamine 4,4'-dithiodimorpholine 1/2/1/2 4.0 black B II - - 1/2 3.3 brownblack J I hexachlorophene/ cyclohexylamine 1/1/1 3.7 purple J II " 4-phenyl3-thiosemicarbazide 1/3/2/2 3.5 black J,L II " - 1/1/2/1 3.2 purpleblack L II - - 1/2 2.7 lavender J II tetrabromobis-phenol A/ cyclohexylamine - 1/4/8 5.0 black J I - - 1/2 4.0 slate blue/ black A II - - 1/2 4.1 black IMAGED SHEETS - cont.

Lactone or Cyclic Other Coating Wt. Trace Spiropyran Polyketone Phenolic Complex Additives Ratios lb/3000 sq ft Color A II hexachlorophene/ cyclohexylamine - 1/1/12 4.0 black A I - - 1/1 4.7 black A II - - 1/10 3.0 dark brown K II 2,2'-thiobis(4,6-dichlorophenol)/ ethanolamine - 1/2/1 1.9 dark brown J II hexachlorophene/ cyclohexylamine - 1/3/8 4.0 black C II - - 1/2 4.5 dark brown C II hexachlorophene/ cyclohexylamine - 1/2/2 3.5 darker brown D II - - 1/2 4.0 redbrown D II hexachlorophene/ cyclohexylamine - 1/2/2 3.5 dark brown IMAGED SHEETS - cont.

Lactone or Cyclic Other Coating Wt. Trace Spiropyran Polyketone Phenolic Complex Additives Ratios lb/3000 sq ft Color F II - - 1/2 4.2 brown F II hexachlorophene/ cycloxylamine - 1/2/2 4.0 dark brown G II - - 1/2 4.3 violetblack G II hexachlorophene/ cyclohexylamine - 1/2/2 5.0 black H II hexachlorophene/ cyclohexylamine - 1/2 4.8 dark brown I II - - 1/2 3.5 blueblack I II hexachlorophene/ cyclohexylamine - 1/2/2 3.2 black M - hexachlorophene/ cyclohexylamine - 1/8 4.0 light blue green M II hexachlorophene/ cyclohexylamine - 1/2 4.3 purplegray IMAGED SHEETS - cont: Lactone or Cyclic Other Coating Wt. Trace Spiropyran Polyketone Phenolic Complex Additives Ratios lb/3000 sq ft Color M II - hexachlorophene 1/2/2 5.0 slate bluegray M II - phenyl urea 1/2/2 4.5 dark blueblack M II - 4-phenylpiperidine 1/2/2 3.7 blueblack M II - 4-hydroxy4-phenyl piperidine 1/2/2 3.7 brown M II - piperazineterephthaldehyde condensate 1/2/2 3.8 olive greenblack Activators may be added to the heat-sensitive compositions of the invention to lower the activation temperatures of the above systems and to intensify the image mark. Some preferred activators are ureas and thioureas such as phenylurea, phenylthiourea and allylurea; carbanilide; thiocarbanilide; zinc acetoacetonate; fatty acid salts of zinc such as zinc stearate and zinc palmitate; and salicylanilide.

Claims (14)

WHAT I CLAIM IS:

1. A mixture of heat-sensitive colour precursors comprising (a) a cyclic polyketo compound reactive with amines and amides at elevated temperatures to form a colour; and (b) a chromogenic compound selected from the group consisting of lactone type leuco dyes and spiropyran type leuco dyes, said chromogenic compound being reactive with phenols at elevated temperatures to form a colour.

2. The mixture of heat-sensitive colour precursors of Claim 1, wherein said cyclic polyketo compound and said chromogenic compound are combined as an adduct.

3. A heat-sensitive recording composition comprising the mixture of heatsensitive colour precursors of Claim 1 or 2 and further comprising (c) binder means for binding the composition to a substrate.

4. The composition of Claim 3 and further comprising (d) a phenol selected from either Table III or Table IV of the specification and (e) an amine or amide.

5. The composition of Claim 4, wherein said phenol and said amine or amide are combined in a hydrogen-bonded molecular complex.

6. The composition of Claim 4 or 5, wherein said chromogenic compound is a lactone selected from Table I of the specification.

7. The composition of Claim 4 or 5, wherein said chromogenic compound is a spiropyran selected from Table II of the specification.

8. The composition of any one of Claims 4 to 7, wherein said cyclic polyketo compound is a compound selected from the group consisting of ninhydrin, hydrindantin, isatin, alloxan and their homologs.

9. The composition of any one of Claims 4 to 8, wherein said amine or amide is selected from Table IV of the specification.

10. The composition of any one of Claims 3 to 9 and further comprising an activator for lowering the temperature of colour formation, said activator comprising a compound selected from the group consisting of ureas; thioureas; carbanilide; thiocarbanilide; zinc acetoacetonate; fatty acid salts of zinc; and salicylanilide.

11. A method of producing a heat-sensitive recording composition comprising the steps of dissolving a binder in a solvent in which complexes of a phenol and a complexing agent selected from the group consisting of amines and amides is insoluble, to form a binder-solvent solution, dispersing in said solution a chromogenic compound reactive with a phenol at elevated temperatures to develop a colour contrasting visibly with the normally colourless background of said composition, said chromogenic compound being selected from the group consisting of lactone type leuco dyes and spiropyran type leuco dyes; a cyclic polyketo compound reactive with amines and amides at elevated temperatures to form a colour contrasting visibly with the normally colourless background of said composition; and a hydrogen-bonded molecular complex of a phenol selected from either Table III or Table IV of the specification and a complexing agent selected from the group consisting of amines and amides, to form a dispersion, applying said dispersion to a substrate, and evaporating solvent from said dispersion to form a thermosensitive coating developing a colour at elevated temperatures.

12. The method of Claim 11, wherein said cyclic polyketo compound is selected from the group consisting of ninhydrin, hydrindantin, isatin, alloxan, and their homologs.

13. A heat-sensitive recording composition, according to any one of Claims 3 to 10, substantially as hereinbefore described with particular reference to the Examples.

14. A method according to Claim 11 or 12, for producing a heat-sensitive recording composition, substantially as hereinbefore described with particular reference to the Examples.