Radiation-sensitive composition and elements with basic development enhancers
View Patent ↗Radiation-sensitive compositions can be used to prepare positive-working imageable elements useful for example to make lithographic printing plates. The compositions include an aqueous alkaline solvent soluble polymeric binder that includes a phenolic resin (such as a novolak) or a poly(vinyl acetal). The compositions also include a developability-enhancing composition comprising one or more basic nitrogen-containing organic compounds. The radiation-sensitive composition can be coated as an imageable layer that further includes a radiation absorbing compound that is, for example, sensitive to infrared radiation.
1. A radiation-sensitive composition comprising:
a. an aqueous alkaline developer soluble polymeric binder that comprises a poly(vinyl acetal), and
b. a developability-enhancing composition comprising a basic nitrogen-containing organic compound,
wherein said developability-enhancing composition comprises one or more basic nitrogen-containing compounds that are represented by the following Structure (II):
(R 7 ) s —N—[(CR 8 R 9 ) t —OH] v (II)
wherein s is 0, 1, or 2 and v is 1 to 3, provided that the sum of s and v is 3, and t is 1 to 6, and
when s is 1, R 7 is hydrogen or an alkyl, alkylamine, cycloalkyl, heterocycloalkyl, aryl, arylamine, or heteroaryl group, and when s is 2, the multiple R 7 groups can be the same or different alkyl, alkylamine, cycloalkyl, heterocycloalkyl, aryl, arylamine, or heteroaryl groups, or the two R 7 groups together with the nitrogen atom, can form a substituted or unsubstituted heterocyclic ring, and
R 8 and R 9 are independently hydrogen or an alkyl group,
wherein said poly(vinyl acetal) comprises recurring units represented by the following Structure (PVAc):
wherein R and R′ are independently hydrogen or an alkyl or halo group, and R 2 is a substituted or unsubstituted phenol, naphthol, or anthracenol group.
2. The radiation-sensitive composition of claim 1 further comprising a radiation absorbing compound.
3. The radiation-sensitive composition of claim 1 wherein said polymeric binder comprises a poly(vinyl acetal) that has from about 50 to about 75 mol % recurring acetal-containing units.
4. The radiation-sensitive composition of claim 3 wherein said polymeric binder comprises a poly(vinyl acetal) that is represented by the following Structure (I):
-(A) m -(B) n-(C) p -(D) q -(E) r - (I)
wherein:
A represents recurring units represented by the following Structure (Ia):
B represents recurring units represented by the following Structure (Ib):
C represents recurring units represented by the following Structure (Ic):
D represents recurring units represented by the following Structure (Id):
E represents recurring units represented by the following Structure (Ie):
m is from about 5 to about 40 mol %, n is from about 10 to about 60 mol %, p is from 0 to about 20 mol %, q is from about 1 to about 20 mol % and r is from about 5 to about 60 mol %, provided that m+n+p is at least 50 mol %,
R and R′ are independently hydrogen or an alkyl or halo group,
R 1 is an alkyl, cycloalkyl, or aryl group other than a phenol or naphthol,
R 2 is a phenol or naphthol group,
R 3 is an alkyl group,
R 4 is an —O—C(═O)—R 5 group wherein R 5 is an alkyl or aryl group, and
R 6 is a hydroxy group.
5. The radiation-sensitive composition of claim 4 wherein m is from about 15 to about 35 mol %, n is from about 20 to about 40 mol %, p is from 0 to about 10 mol %, q is from about 1 about 15 mol %, r is from about 15 to about 55 mol %, and s is from about 5 to about 15 mol %.
6. The radiation-sensitive composition of claim 1 wherein t is 2 and R 8 and R 9 are both hydrogen.
7. The radiation-sensitive composition of claim 1 wherein said developability-enhancing composition comprises one or more of N-(2-hydroxyethyl)-2-pyrrolidone, 1-(2-hydroxyethyl)piperazine, N-phenyldiethanolamine, triethanolamine, 2-[bis(2-hydroxyethyl)amino]-2-hydroxymethyl-1.3-propanediol, N,N,N′,N′-tetrakis(2-hydroxyethyl)-ethylenediamine, N,N,N′,N′-tetrakis(2-hydroxypropyl)-ethylenediamine, 3-[(2-hydroxyethyl)phenylamino]propionitrile, and hexahydro-1,3,5-tris(2-hydroxyethyl)-s-triazine.
8. The radiation-sensitive composition of claim 1 wherein said one or more basic nitrogen-containing organic compounds are present in an amount of from about 1 to about 30% of the total radiation-sensitive composition solids.
9. The radiation-sensitive composition of claim 1 comprising two or more of said basic nitrogen-containing organic compounds.
10. The radiation-sensitive composition of claim 1 comprising one or more of said basic nitrogen-containing organic compounds and one or more acidic developability-enhancing compounds.
11. The radiation-sensitive composition of claim 1 wherein said basic nitrogen-containing organic compound is a liquid at 25° C., or it has a boiling point greater than 300° C. and an evaporation rate <0.01 relative to n-butyl acetate.
12. A positive-working imageable element comprising a substrate, and having thereon:
an imageable layer comprising an aqueous alkaline developer soluble polymeric binder that comprises a poly(vinyl acetal), a developability-enhancing composition comprising a basic nitrogen-containing compound, and a radiation absorbing compound,
wherein said developability-enhancing composition comprises one or more basic nitrogen-containing compounds that are represented by the following Structure (II):
(R 7 ) s —N—[(CR 8 R 9 ) t —OH] v (II)
wherein s is 0, 1, or 2 and v is 1 to 3, provided that the sum of s and v is 3, and t is 1 to 6, and
when s is 1, R 7 is hydrogen or an alkyl, alkylamine, cycloalkyl, heterocycloalkyl, aryl, arylamine, or heteroaryl group, and when s is 2, the multiple R 7 groups can be the same or different alkyl, alkylamine, cycloalkyl, heterocycloalkyl, aryl, arylamine, or heteroaryl groups, or the two R 7 groups together with the nitrogen atom, can form a substituted or unsubstituted heterocyclic ring, and
R 8 and R 9 are independently hydrogen or an alkyl group.
13. The element of claim 12 wherein said polymeric binder is present at a coverage of from about 30 to about 95 weight %, said developability-enhancing composition is present at a coverage of from about 1 to about 30 weight %, and said radiation absorbing compound is an infrared radiation absorbing compound that is present at a coverage of from about 0.1 to about 20 weight %, all based on the total dry weight of said imageable layer.
14. The element of claim 12 wherein said polymeric binder comprises a poly(vinyl acetal) that comprises recurring units represented by the following Structure (PVAc):
wherein R and R′ are independently hydrogen or an alkyl or halo group, and R 2 is a substituted or unsubstituted phenol, naphthol, or anthracenol group.
15. The element of claim 12 wherein said polymeric binder comprises a poly(vinyl acetal) that is represented by the following Structure (I):
-(A) m -(B) n -(C) p -(D) q (E) r - (I)
wherein:
A represents recurring units represented by the following Structure (Ia):
B represents recurring units represented by the following Structure (Ib):
C represents recurring units represented by the following Structure (Ic):
D represents recurring units represented by the following Structure (Id):
E represents recurring units represented by the following Structure (Ie):
m is from about 5 to about 40 mol %, n is from about 10 to about 60 mol %, p is from 0 to about 20 mol %, q is from about 1 to about 20 mol %, and r is from about 5 to about 60 mol %, provided that m+n+p is at least 50 mol %,
R and R′ are independently hydrogen or an alkyl or halo group,
R 1 is an alkyl, cycloalkyl, or aryl group other than a phenol or naphthol,
R 2 is a phenol or naphthol group,
R 3 is an alkyl group,
R 4 is an —O—C(═O)—R 5 group wherein R 5 is an alkyl or aryl group, and
R 6 is a hydroxy group.
16. The element of claim 15 wherein t is 2 and R 8 and R 9 are both hydrogen.
17. The element of claim 12 wherein said developability-enhancing composition comprises one or more of N-(2-hydroxyethyl)-2-pyrrolidone, 1-(2-hydroxyethyl)piperazine, N-phenyldiethanolamine, triethanolamine, 2-[bis(2-hydroxyethyl)amino]-2-hydroxymethyl-1.3-propanediol, N,N,N′,N′-tetrakis(2-hydroxyethyl)-ethylenediamine, N,N,N′,N′-tetrakis(2-hydroxypropyl)-ethylenediamine, 3-[(2-hydroxyethyl)phenylamino]propionitrile, and hexahydro-1,3,5-tris(2-hydroxyethyl)-s-triazine.
18. The element of claim 12 wherein said basic nitrogen-containing organic compound is a liquid at 25° C., or it has a boiling point greater than 300° C. and an evaporation rate <0.01 relative to n-butyl acetate.
19. The element of claim 12 wherein said developability-enhancing composition comprises one or more of N-(2-hydroxyethyl)-2-pyrrolidone, triethanolamine, and N,N,N′,N′-tetrakis(2-hydroxypropyl)-ethylenediamine, in an amount of from about 3 to about 15 weight % based on the total dry weight of said imageable layer.
20. A method of making a printing plate comprising:
A) imagewise exposing the positive-working imageable element of claim 12 to provide exposed and non-exposed regions, and
B) developing said imagewise exposed element to remove only said exposed regions.
21. The method of claim 20 wherein said imageable element is imaged at a wavelength of from about 700 to about 1200 nm.
22. The method of claim 20 wherein said imageable element comprises a polymeric binder in said imageable layer that comprises a poly(vinyl acetal) that comprises recurring units represented by the following Structure (PVAc):
wherein R and R′ are independently hydrogen or an alkyl or halo group, and R 2 is a substituted or unsubstituted phenol, naphthol, or anthracenol group, and
said developability-enhancing composition comprises one or more basic nitrogen-containing organic compounds that are represented by the following Structure (II):
(R 7 ) s —N—[(CR 8 R 9 ) t —OH] v (II)
wherein s is 0, 1, or 2 and v is 1 to 3, provided that the sum of s and v is 3, and t is 1 to 6, and
when s is 1, R 7 is hydrogen or an alkyl, alkylamine, cycloalkyl, heterocycloalkyl, aryl, arylamine, or heteroaryl group, and when s is 2, the multiple R 7 groups can be the same or different alkyl, alkylamine, cycloalkyl, heterocycloalkyl, aryl, arylamine, or heteroaryl groups, or the two R 7 groups together with the nitrogen atom, can form a substituted or unsubstituted heterocyclic ring, and
R 8 and R 9 are independently hydrogen or an alkyl group.