Claims
- 1. A method of imaging comprising the steps of:A) providing an imaging member comprising a support having disposed thereon a hydrophilic imaging layer, and B) imagewise exposing said imaging member to provide exposed and unexposed areas in the imaging layer of said imaging member, whereby said exposed areas are rendered more hydrophobic than said unexposed areas by heat provided by said imagewise exposure, said hydrophilic imaging layer being prepared from a) a hydrophilic heat-sensitive ionomer, b) water or a water-miscible organic solvent, and c) an infrared radiation sensitive dye that is soluble in water or said water-miscible organic solvent, wherein the infrared radiation sensitive dye comprises an organic moiety comprising an infrared sensitive group and at least three sulfo groups covalently bound to the organic moiety, wherein said heat-sensitive ionomer is selected from the following two classes of polymers: I) a crosslinked or uncrosslinked vinyl polymer comprising recurring unites comprising positively-charged, pendant N-alkylated aromatic heterocyclic groups represented by the Structure I wherein R1 is an alkyl group, R2 is an alkyl group, an alkoxy group, an aryl group, an alkenyl, halo, a cycloalkyl group, or a heterocyclic group having 5 to 8 atoms in the ring, Z″ represents the carbon and nitrogen, oxygen, or sulfur atoms necessary to complete an aromatic N-heterocyclic ring having 5 to 10 atoms in the ring, n is 0 to 6, and W− is an anion, and II) a crosslinked polymer comprising recurring organoonium groups represented by the structure VI: wherein ORG represents organoonium groups, X′ represents recurring units to which the ORG groups are attached, Y′ represents recurring units derived from ethylenically unsaturated polymerizable monomers that may provide active sites for crosslinking, Z′ represents recurring units derived from any additional ethylenically unsaturated polymerizable monomers, x′ is from about 20 to about 99 mol %, y′ is from about 1 to about 20 mol % and z′ is from 0 to about 79 mol %.
- 2. The method of claim 1 wherein said imagewise exposing is carried out using an IR radiation emitting laser, and said imaging member is a lithographic printing plate having an aluminum support or an imaging cylinder.
- 3. The method of claim 1 wherein said imagewise exposing is accomplished using a thermal head.
- 4. The method of claim 1 wherein said IR dye is a cyanine dye having two nitrogen atoms conjugated with a polymethine chain that is terminated with two cyclic groups.
- 5. The method of claim 4 wherein said polymethine chain is conjugated with one or more aromatic carbocyclic or aromatic or non-aromatic heterocyclic groups.
- 6. The method of claim 1 wherein said IR dye is represented by Structure DYE-1: wherein A and B are independently cyclic groups, L is a chromophoric chain comprising at least 3 carbon atoms that is conjugated to A and B, R6, R7, R8 and R9 are independently substituents selected from the group consisting of sulfo, alkyl, alkoxy, halo, carboxy, and aryl groups, M is a cation, x− is the overall anionic charge, and w and z are integers to provide positive charge to balance x−.
- 7. The method of claim 6 wherein,A and B are independently phenyl, naphthyl, tolyl, pyridyl, pyrimidyl, quinolinyl, phenanthridyl, indolyl, benzindolyl or naphthindolyl groups.
- 8. The method of claim 7 wherein A and B are independently phenyl, naphthyl, indolyl, benzindolyl or naphthindolyl groups, L comprises at least 5 carbon atoms.
- 9. The method of claim 8 wherein A and B are independently indolyl or benzindolyl groups, and L has from 7 to 9 carbon atoms.
- 10. The method of claim 1 wherein said water or water-miscible organic solvent comprises water, methanol, ethanol, 1-methoxy-2-propanol, or a mixture of two or more of these.
- 11. The method of claim 1 wherein R1 is an alkyl group of 1 to 6 carbon atoms, R2 is a methyl, ethyl or n-propyl group, Z″ represents the carbon and nitrogen, oxygen, or sulfur atoms to complete a 5-membered ring, and n is 0 or 1.
- 12. The method of claim 1 wherein x′ is from about 30 to about 98 mol %, y′ is from about 2 to about 10 mol % and z′ is from 0 to about 68 mol %.
- 13. The method of claim 1 wherein said heat-sensitive polymer is present at from about 1 to about 10% solids, and said IR dye is present at from about 0.1 to about 1% solids.
- 14. A method of printing comprising the steps of:A) providing an imaging member comprising a support having disposed thereon a hydrophilic imaging layer, B) imagewise exposing said imaging member to provide exposed and unexposed areas in the imaging layer of said imaging member, whereby said exposed areas are rendered more hydrophobic than said unexposed areas by heat provided by said imagewise exposure, and C) contacting said imagewise exposed imaging member with a lithographic printing ink, and imagewise transferring said printing ink to a receiving material, said hydrophilic imaging layer being prepared from a) a hydrophilic heat-sensitive ionomer, b) water or a water-miscible organic solvent, and c) an infrared radiation sensitive dye that is soluble in water or said water-miscible organic solvent, wherein the infrared radiation sensitive dye comprises an organic moiety comprising an infrared sensitive group and at least three sulfo groups covalently bound to the organic moiety; wherein said heat-sensitive ionomer is selected from the following two classes of polymers: I) a crosslinked or uncrosslinked vinyl polymer comprising recurring units comprising positively-charged, pendant N-alkylated aromatic heterocyclic groups represented by the Structure I wherein R1 is an alkyl group, R2 is an alkyl group, an alkoxy group, an aryl group, an alkenyl, halo, a cycloalkyl group, or a heterocyclic group having 5 to 8 atoms in the ring, Z″ represents the carbon and nitrogen, oxygen, or sulfur atoms necessary to complete an aromatic N-heterocyclic ring having 5 to 10 atoms in the ring, n is 0 to 6, and W− is an anion, and II) a crosslinked polymer comprising recurring organoonium groups epresented by the structure VI: wherein ORG represents organoonium groups, X′ represents recurring units to which the ORG groups are attached, Y′ represents recurring units derived from ethylenically unsaturated polymerizable monomers that may provide active sites for crosslinking, Z′ represents recurring units derived from any additional ethylenically unsaturated polymerizable monomers, x′ is from about 20 to about 99 mol %, y′ is from about 1 to about 20 mol %, and z′ is from 0 to about 79 mol %.
- 15. A method of imaging comprising the steps of:A) spray coating a heat-sensitive composition onto a support to provide an imaging member, and B) imagewise exposing said imaging member to provide exposed and unexposed areas in the imaging layer of said imaging member, whereby said exposed areas are rendered more hydrophobic than said unexposed areas by heat provided by said imagewise exposure, said heat-sensitive composition comprising: a) a hydrophilic heat-sensitive ionomer, b) water or a water-miscible organic solvent, and c) an infrared radiation sensitive dye that is soluble in water or said water-miscible organic solvent, wherein the infrared radiation sensitive dye comprises an organic moiety comprising an infrared sensitive group and at least three sulfo groups covalently bound to the organic moiety, wherein said heat-sensitive ionomer is selected from the following two classes of polymers: I) a crosslinked or uncrosslinked vinyl polymer comprising recurring units comprising positively-charged, pendant N-alkylated aromatic heterocyclic groups represented by the Structure I wherein R1 is an alkyl group, R2 is an alkyl group, an alkoxy group, an aryl group, an alkenyl, halo, a cycloalkyl group, or a heterocyclic group having 5 to 8 atoms in the atoms in the ring, Z″ represents the carbon and nitrogen, oxygen, or sulfur atoms necessary to complete an aromatic N-heterocyclic ring having 5 to 10 atoms in the ring, n is 0 to 6, and W− is an anion, and II) a crosslinked polymer comprising recurring organoonium groups represented by the structure VI: wherein ORG represents organoonium groups, X′ represents recurring units to which the ORG groups are attached, Y′ represents recurring units derived from ethylenically unsaturated polymerizable monomers that may provide active sites for crosslinking, Z′ represents recurring units derived from any additional ethylenically unsaturated polymerizable monomers, x′ is from about 20 to about 99 mol %, y′ is from about 1 to about 20 mol %, and z′ is from 0 to about 79 mol %.
- 16. The method of claim 15 wherein said support is an on-press printing cylinder or sleeve.
- 17. A method of imaging comprising the steps of:A) providing an imaging member comprising a support having disposed thereon a hydrophilic imaging layer, and B) imagewise exposing said imaging member to provide exposed and unexposed areas in the imaging layer of said imaging member, whereby said exposed areas are rendered more hydrophobic than said unexposed areas by heat provided by said imagewise exposure, said hydrophilic imaging layer being prepared from a) a hydrophilic heat-sensitive ionomer, b) water or a water-miscible organic solvent, and c) an infrared radiation sensitive dye that is soluble in water or said water-miscible organic solvent and has at least three sulfo groups, wherein said heat-sensitive ionomer is selected from the following two classes of polymers: I) a crosslinked or uncrosslinked vinyl polymer comprising recurring unites comprising positively-charged, pendant N-alkylated aromatic heterocyclic groups represented by the Structure I wherein R1 is an alkyl group, R2 is an alkyl group, an alkoxy group, an aryl group, an alkenyl, halo, a cycloalkyl group, or a heterocyclic group having 5 to 8 atoms in the ring, Z″ represents the carbon and nitrogen, oxygen, or sulfur atoms necessary to complete an aromatic N-heterocyclic ring having 5 to 10 atoms in the ring, n is 0 to 6, and W− is an anion, and II) a crosslinked polymer comprising recurring organoonium groups represented by the structure VI: wherein ORG represents organoonium groups, X′ represents recurring units to which the ORG groups are attached, Y′ represents recurring units derived from ethylenically unsaturated polymerizable monomers that may provide active sites for crosslinking, Z′ represents recurring units derived from any additional ethylenically unsaturated polymerizable monomers, x′ is from about 20 to about 99 mol %, y′ is from about 1 to about 20 mol % and z′ is from 0 to about 79 mol %, wherein said infrared radiation sensitive dye is represented by Structure DYE-2 wherein R10 and R11 are independently sulfo, R12 and R14 are independently hydrogen, alkyl or aryl groups, or together represent the carbon atoms necessary to complete a 5- to 6-membered carbocyclic ring, R13 is hydrogen, or an alkyl, aryl, halo, thioalkyl, thioaryl, cyano, amino or heterocyclic group, p and q are integers of 1 to 3, Z1 and Z2 independently represent the atoms needed to complete an indolyl, benindolyl or naphthindolyl group, M is a cation, and w and z are integers to provide positive charge to balance the total charge of the dye anion.
- 18. The method of claim 17 wherein R10 and R11 are independently, sulfoalkyl having 1 to 4 carbon atoms, sulfoalkenyl, sulfoaryl, sulfoalkynyl, or oxysulfonate.
- 19. A method of imaging comprising the steps of:A) providing an imaging member comprising a support having disposed thereon a hydrophilic imaging layer, and B) imagewise exposing said imaging member to provide exposed and unexposed areas in the imaging layer of said imaging member, whereby said exposed areas are rendered more hydrophobic than said unexposed areas by heat provided by said imagewise exposure, said hydrophilic imaging layer being prepared from a) a hydrophilic heat-sensitive ionomer, b) water or a water-miscible organic solvent, and c) an infrared radiation sensitive dye that is soluble in water or said water-miscible organic solvent and has at least three sulfo groups, wherein said heat-sensitive ionomer is selected from the following two classes of polymers: I) a crosslinked or uncrosslinked vinyl polymer comprising recurring unites comprising positively-charged, pendant N-alkylated aromatic heterocyclic groups represented by the Structure I wherein R1 is an alkyl group, R2 is an alkyl group, an alkoxy group, an aryl group, an alkenyl, halo, a cycloalkyl group, or a heterocyclic group having 5 to 8 atoms in the ring, Z″ represents the carbon and nitrogen, oxygen, or sulfur atoms necessary to complete an aromatic N-heterocyclic ring having 5 to 10 atoms in the ring, n is 0 to 6, and W− is an anion, and II) a crosslinked polymer comprising recurring organoonium groups represented by the structure VI: wherein ORG represents organoonium groups, X′ represents recurring units to which the ORG groups are attached, Y′ represents recurring units derived from ethylenically unsaturated polymerizable monomers that may provide active sites for crosslinking, Z′ represents recurring units derived from any additional ethylenically unsaturated polymerizable monomers, x′ is from about 20 to about 99 mol %, y′ is from about 1 to about 20 mol % and z′ is from 0 to about 79 mol %, wherein said infrared radiation sensitive dye is selected from the group consisting of IR Dye 1, IR Dye 2, IR Dye 3, IR Dye 4, IR Dye 5, IR Dye 6, and IR Dye 7:
- 20. A method of imaging comprising the steps of:A) providing an imaging member comprising a support having disposed thereon a hydrophilic imaging layer, and B) imagewise exposing said imaging member to provide exposed and unexposed areas in the imaging layer of said imaging member, whereby said exposed areas are rendered more hydrophobic than said unexposed areas by heat provided by said imagewise exposure, said hydrophilic imaging layer being prepared from a) a hydrophilic heat-sensitive ionomer, b) water or a water-miscible organic solvent, and c) an infrared radiation sensitive dye that is soluble in water or said water-miscible organic solvent, wherein the infrared radiation sensitive dye comprises an organic moiety comprising an infrared sensitive group and at least three sulfo groups covalently bound to the organic moiety, wherein said heat-sensitive ionomer is a crosslinked polymer represented by either of Structures III or IV: wherein R is an alkylene, arylene, or cycloalkylene group or a combination of two or more such groups, R3, R4 and R5 are independently substituted or unsubstituted alkyl, aryl or cycloalkyl groups, or any two of R3, R4 and R5 can be combined to form a heterocyclic ring with the charged phosphorus or sulfur atom, and W− is an anion.
- 21. The method of claim 20 wherein R is an ethyleneoxycarbonyl or phenylenemethylene group, and R3, R4 and R5 are independently a methyl or ethyl group, and W− is a halide or carboxylate.
CROSS-REFERENCE TO RELATED APPLICATION
This is a Divisional of application Ser. No. 09/387,021 filed Aug. 31, 1999, U.S. Pat. No. 6,159,657, now allowed.
US Referenced Citations (16)
Foreign Referenced Citations (3)
Number |
Date |
Country |
0 251 282 |
Jan 1988 |
EP |
0 652 483 |
May 1995 |
EP |
9209934 |
Jun 1992 |
WO |
Non-Patent Literature Citations (1)
Entry |
Research Disclosure, Item 19201, Apr., 1980. |