Leuco dye/hexaarylbiimidazole thermally activated imaging process

Claim 2

A process which comprises the process of claim 1, followed by the additional step of c. cooling said heated and radiated composition to a temperature below the temperature specified in step (a) of claim 1.

Claim 3

at least one aminotriarylmethane dye in the leuco form wherein at least two of the aryl groups are phenyl groups having (a) an R1R2N-substituted in the position para to the bond to the methane carbon atom wherein R1 and R2 are each groups selected from hydrogen, C1 to C10 alkyl, 2-hydroxyethyl, 2-cyanoethyl, benzyl or phenyl, and (b) a group ortho to the bond to the methane carbon atom which is selected from lower alkyl, lower alkoxy, fluorine, chlorine, bromine, or butadienylene which when joined to the phenyl group forms a naphthalene ring; and the third aryl group; when different from the first two, is selected from thienyl, furyl, oxazylyl, pyridyl, thiazolyl, indolyl, indolinyl, benzoxazolyl, quinolyl, benzothiazolyl, phenyl, naphthyl, or such aforelisted groups substituted with lower alkyl, lower alkoxyl, methylenedioxy, fluoro, chloro, bromo, amino, lower alkylamino, lower dialkylamino, lower alkylthio, hydroxy, carboxy, carbonamido, lower carbalkoxy, lower alkylsulfonyl, lower alkylsulfonamide, C1 and C10 arylsulfonamido, nitro or benzylthio, and

Claim 4

at least one dye in the leuco form having one or two removable hydrogens, the removal of which forms a differently colored dye with the proviso that when the leuco form has only one removable hydrogen and the resultant dye is cationic, there is also present an acid which forms a salt with the leuco form of the dye, and

Claim 5

a binder within which components (1) and (2) are dispersed, to photoradiation of wavelength and intensity effective to activate the hexaarylbiimidazole, b. followed by substantially immediately raising the temperature of the composition until the composition forms colored image.

Claim 6

an amorphous thermoplastic binder within which components (1) and (2) are dispersed, said binder having a glass transition temperature above 25* C. but below the decomposition temperature of components (1) and (2), to an activation temperature above the glass transition temperature of the binder but below the decomposition temperature of components (1) and (2), said composition being substantially free of solvent, and b. subjecting the composition, while at said activation temperature, to photoradiation of wavelength and intensity effective to induce colored image formation.

Claim 7

The process of claim 1 wherein the hexaarylbiimidazole is a hexaphenylbiimidazole in which the phenyl groups can contain noninterfering substituents which have Hammett sigma values in the -0.5 to +0.8 range; the dye in the leuco form is selected from aminotriarylmethanes, aminoxanthenes, aminothioxanthenes, amino-9,10-dihydroacridines, aminophenoxazines, aminophenothiazines, aminodihydrophenazines, aminodiphenylmethanes, leuco indamines, aminohydrocinnamic acids, hydrazines, leuco indigoid dyes, amino-2,3-dihydroanthraquinones, tetrahalo-p,p''-biphenols, 2(p-hydroxyphenyl)-4,5-diphenylimidazoles, or phenethylanilines, and the binder is an amorphous thermoplastic polymer.

Claim 8

an amorphous thermoplastic binder within which components (1) and (2) are dispersed, to an activation temperature above the glass transition temperature of the binder but below the decomposition temperatures of components (1) and (2), said composition being substantially free of solvents, and b. subjecting said composition, while at said activating temperature, to photoradiation exposure effective to induce color formation.

Claim 9

Process for imaging photosensitive color-forming compositions which comprises a. heating a composition consisting essentially of an admixture of

Claim 10

The process of claim 4 wherein the glass transition temperature of the binder is between 30* C. and 130* C., and the composition is heated in step (a) to a temperature of from about 20* to about 50* C. above the glass transition temperature of the binder.

Claim 11

The process of claim 4 wherein in the 2,2'' ,4,4'' ,5,5''-hexaphenylbiimidazole, the 2 and 2'' phenyl groups are each substituted with one ortho-chloro group and the 4,4'' ,5 and 5'' phenyl groups are each unsubstituted or are each substituted with one meta-methoxy group; the dye in the leuco form is a strong acid salt of an aminotriarylmethane of the formula

Claim 12

The process of claim 6 wherein in the aminotriarylmethane, K3 and R4 are lower alkyl, Y and Y'' are lower alkyl, and X is

Claim 13

A process which comprises the process of claim 7, followed by the additional step of c. cooling the composition to a temperature below the glass transition temperature specified in step (a) of claim 7.

Claim 14

A process for imaging photosensitive color-forming compositions which comprises a. subjecting a composition which is substantially free of solvent and consists essentially of

Claim 15

A process which comprises the process of claim 9, followed by the additional step of c. cooling the composition to a temperature below the temperature at which the composition formed color.