Dye solution and process for the preparation of information recording medium

Claim 2

A dye solution comprising a cyanine dye and a diimmonium compound dissolved in a liquid fluorine-­containing compound, wherein: said cyanine dye has the formula (I): Φ ⁺ -(CH=CH) n CH = Ψ (X m- ) 1/m (I) in which each of Φ and Ψ is independently a residue of an indolenine ring, a thiazole ring, an oxazole ring, a selenazole ring, an imidazole ring, a pyridine ring, a thiazolopyrimidine ring, an imidzoquinoxaline ring or an amine, each of which may be condensed with an aromatic ring; n is 0 or an integer of 1 to 5; X m- is an m-valent anion; m is 0 or 1; and X m- may be substituted on Φ , -(CH=CH) n CH= or Ψ to form an inner salt; and said diimmonium compound has the formula (II): in which each of R¹, R², R³, and R⁴ is independently an alkyl group, an alkenyl group or aryl group,each of which may be a substituted group; each of R⁵, R⁶, R⁷ and R⁸ is independently hydrogen, a halogen atom, an alkyl group which may be a substituted group, an alkenyl group which may be a substituted group, a phenyl group which may be a substituted group, an alkoxy group which may be a substituted group, a phenoxy group which may be a substituted group, an acyl group which may be a substituted group, alkylsulfonyl group which may be a substituted group, a benzensulfonyl group which may be a substituted group, or a cyano group; n is 1 or 2; and each combination of R¹ and R², R³ and R⁴, R⁵ and R⁶, and R⁷ and R⁸ may be linked to each other, respectively, to form a ring.

Claim 3

The dye solution as claimed in claim 1, wherein each of Φ and Ψ in the formula (I) is a residue of an indolenine ring or an imidazoquinoxaline ring, each of which may be condensed with an aromatic ring.

Claim 4

The dye solution as claimed in claim 1, wherein the liquid fluorine-containing compound is at least one compound selected from the group consisting of a fluorinated alcohol, a fluorine-substituted ketone, a fluorine-substituted ester, a fluorine-substituted amide, a fluorine-substituted benzene, a fluorinated alkane and a fluorinated ether.

Claim 5

The dye solution as claimed in claim 1, wherein the liquid fluorine-containing compound is a fluorinated alcohol having the formula (III): A-CH₂OH      (III) in which A is F(C n F 2n ) or H(C n F 2n ) wherein n is as integer of 1 to 6.

Claim 6

The dye solution as claimed in claim 1, wherein the ration between the cyanine dye and the diimmonium compound is in the range of 99.99 : 0.01 to 50 : 50.

Claim 7

A process for the preparation of an information recording medium comprising a plastic substrate and a recording layer of dye for writing or reading information by means of a laser beam which is provided on the substrate, wherein said recording layer is formed on the substrate by coating a dye solution composition which contains a cyanine dye and a diimmonium compound dissolved in a fluorine-containing compound solvent over the substrate to form a coated layer, and drying the coated layer; said cyanine dye has the formula (I): Φ ⁺ -(CH=CH) n CH = Ψ (X m- ) 1/m (I) in which each of Φ and Ψ is independently a residue of an indolenine ring, a thiazole ring, an oxazole ring, a selenazole ring, an imidazole ring, a pyridine ring, a thiazolopyrimidine ring, an imidzoquinoxaline ring or an amine, each of which may be condensed with an aromatic ring; n is 0 or an integer of 1 to 5; X m- is an m-valent anion; m is 0 or 1; and X m- may be substituted on Φ , -(CH=CH) n CH= or Ψ to form an inner salt;and said diimmonium compound has the formula (II): in which each of R¹, R², R³, and R⁴ is independently an alkyl group, an alkenyl group or an aryl group, each of which may be a substituted group; each of R⁵, R⁶, R⁷ and R⁸ is independently hydrogen, a halogen atom, an alkyl group which may be a substituted group, an alkenyl group which may be a substituted group, a phenyl group which may be a substituted group, an alkoxy group which may be a substituted group, a phenoxy group which may be a substituted group, an acyl group which may be a substituted group, an alkylsulfonyl group which may be a substituted group, a benzensulfonyl group which may be a substituted group, or a cyano group; n is 1 or 2; and each combination of R¹ and R², R³ and R⁴, R⁵ and R⁶, and R⁷ and R⁸ may be linked to each other, respectively, to form a ring.

Claim 8

A process for the preparation of an information recording medium comprising a plastic substrate and a recording layer of dye for writing or reading information by means of a laser beam which is provided on the substrate, wherein said recording layer is formed on the substrate by coating a dye solution composition which contains a cyanine dye and a diimmonium compound dissolved in a fluorine-containing compound solvent over the substrate to form a coated layer, and drying the coated layer; said cyanine dye has the formula (I): Φ ⁺ -(CH=CH) n CH = Ψ (X m- ) 1/m (I) in which each of Φ and Ψ is independently a residue of an indolenine ring, a thiazole ring, an oxazole ring, a selenazole ring, an imidazole ring, a pyridine ring, a thiazolopyrimidine ring, an imidzoquinoxaline ring or an amine, each of which may be condensed with an aromatic ring; n is 0 or an integer of 1 to 5; X m- is an m-valent anion; m is 0 or 1; and X m- may be substituted on Φ , -(CH=CH) n CH= or Ψ to form an inner salt;and said diimmonium compound has the formula (II): in which each of R¹, R², R³, and R⁴ is independently an alkyl group, an alkenyl group or an aryl group, each of which may be a substituted group; each of R⁵, R⁶, R⁷ and R⁸ is independently hydrogen, a halogen atom, an alkyl group which may be a substituted group, an alkenyl group which may be a substituted group, a phenyl group which may be a substituted group, an alkoxy group which may be a substituted group, a phenoxy group which may be a substituted group, an acyl group which may be a substituted group, an alkylsulfonyl group which may be a substituted group, a benzensulfonyl group which may be a substituted group, or a cyano group; n is 1 or 2; and each combination of R¹ and R², R³ and R⁴, R⁵ and R⁶, and R⁷ and R⁸ may be linked to each other, respectively, to form a ring.

Claim 9

The process for the preparation of an information recording medium as claimed in claim 6, wherein each of Φ and Ψ in the formula (I) is a residue of an indolenine ring or an imidazoquinoxaline ring, each of which may be condensed with an aromatic ring.

Claim 10

The process for the preparation of an information recording medium as claimed in claim 6, wherein the liquid fluorine-containing compound is at least one compound selected from the group consisting of a fluorinated alcohol, a fluorine-substituted ketone, a fluorine-­substituted ester, a fluorine-substituted amide, a fluorine-substituted benzene, a fluorinated alkane and a fluorinated ether.

Claim 11

The process for the preparation of an information recording medium as claimed in claim 6, wherein the liquid fluorine-containing compound is a fluorinated alcohol having the formula (III): A-CH₂OH      (III) in which A is F(C n F 2n ) or H(C n F 2n ) wherein n is as integer of 1 to 6.

Claim 12

The process for the preparation of an information recording medium as claimed in claim 6, wherein the ration between the cyanine dye and the diimmonium compound is in the range of 99.99 : 0.01 to 50 : 50.

Claim 13

The process for the preparation of an information recording medium as claimed in claim 6, wherein the plastic substrate is made of polycarbonate.