Heat-sensitive imaging element
View Patent ↗A heat-sensitive imaging element includes an IR dye, and more particularly a heat-sensitive lithographic printing plate precursor includes the IR dye. A method for making the lithographic printing plate produces a print-out image of high contrast upon exposure to IR-radiation or heating.
1. A heat-sensitive imaging element comprising an IR dye wherein the IR dye has a structure according to Formula I:
wherein
+ Y 1 =is represented by one of the following structures:
Y 2 —is represented by one of the following structures:
n is 0, 1, 2, or 3;
each of p and q is 0, 1, or 2;
R 1 and R 2 are independently an optionally substituted hydrocarbon group, or wherein two of the R 1 , R 2 , R d , or R a groups together include the necessary atoms to form a cyclic structure;
at least one of the R d groups is selected from the list consisting of:
—(N═CR 17 ) a —NR 5 —CO—R 4 ,
—(N═CR 17 ) b —NR 5 —SO 2 —R 6 ,
—(N═CR 17 ) c —NR 11 —SO—R 12 ,
—SO 2 —NR 15 R 16 ; and
—S—CH 2 —CR 7 (H) 1-d (R 8 ) d —NR 9 —COOR 18 ;
wherein
a, b, c, and d independently are 0 or 1;
R 17 is a hydrogen atom, an optionally substituted aliphatic hydrocarbon group, or an optionally substituted (hetero)aryl group, or wherein R 17 and R 5 , R 17 and R 11 together include the necessary atoms to form a cyclic structure;
R 4 is —OR 10 , —NR 13 R 14 , or —CF 3 ;
R 10 is an optionally substituted (hetero)aryl group or an optionally branched aliphatic hydrocarbon group;
R 13 and R 14 independently are a hydrogen atom, an optionally substituted aliphatic hydrocarbon group, or an optionally substituted (hetero)aryl group, or wherein R 13 and R 14 together include the necessary atoms to form a cyclic structure;
R 6 is an optionally substituted aliphatic hydrocarbon group or an optionally substituted (hetero)aryl group, —OR 10 , —NR 13 R 14 , or —CF 3 ;
R 5 is a hydrogen atom, an optionally substituted aliphatic hydrocarbon group, a SO 3 − group, a —COOR 18 group, or an optionally substituted (hetero)aryl group, or wherein R 5 together with at least one of R 10 , R 13 , and R 14 include the necessary atoms to form a cyclic structure;
R 11 , R 15 , and R 16 are independently a hydrogen atom, an optionally substituted aliphatic hydrocarbon group, or an optionally substituted (hetero)aryl group; or wherein R 15 and R 16 together include the necessary atoms to form a cyclic structure;
R 12 is an optionally substituted aliphatic hydrocarbon group or an optionally substituted (hetero)aryl group;
R 7 and R 9 independently are a hydrogen atom or an optionally substituted aliphatic hydrocarbon group;
R 8 is —COO − or —COOR 8′ ; wherein R 8′ is a hydrogen atom, an alkali metal cation, an ammonium ion, or a mono-, di-, tri- or tetra-alkyl ammonium ion;
R 18 is an optionally substituted (hetero)aryl group or an alpha-branched aliphatic hydrocarbon group;
R a and other R d groups are independently represented by a group selected from the list consisting of a hydrogen atom, a halogen atom, —R e , —OR f , —SR g , and —NR u R v ; wherein R e , R f , R g , R u , and R v independently are an optionally substituted aliphatic hydrocarbon group or an optionally substituted (hetero)aryl group; and
the IR dye further comprises one or more counter ions in order to obtain an electrically neutral molecule.
2. The IR dye according to claim 1 , wherein the IR dye has the structure of Formula II, III, or IV;
wherein
Ar 1 , Ar 2 and Ar 3 are independently an optionally substituted aromatic hydrocarbon group or an aromatic hydrocarbon group with an annulated benzene ring which is optionally substituted,
W 1 and W 2 are independently a sulphur atom or a —CM 10 M 11 group wherein M 10 and M 11 are independently an optionally substituted aliphatic hydrocarbon group or an optionally substituted (hetero)aryl group, or wherein M 10 and M 11 together comprise the necessary atoms to form a cyclic structure,
M 1 and M 2 are independently a hydrogen atom, an optionally substituted aliphatic hydrocarbon group or wherein M 1 and M 2 together comprise the necessary atoms to form an optionally substituted cyclic structure,
M 3 and M 4 are independently an optionally substituted aliphatic hydrocarbon group,
M 5 , M 6 , M 7 , M 8 , M 16 and M 17 are independently a hydrogen atom, a halogen atom or an optionally substituted aliphatic hydrocarbon group,
W 3 is a sulphur atom or a —C(A 3 )=C(A 4 )- group,
M 12 and M 13 are independently an optionally substituted aliphatic hydrocarbon group or an optionally substituted (hetero)aryl group, or wherein two of the M 12 , M 13 , A 2 or A 4 together comprise the necessary atoms to form at least one cyclic structure,
W 4 is a sulphur atom or a —C(A 7 )=C(A 8 )- group,
A 1 to A 8 are independently a hydrogen atom, a halogen atom, an optionally substituted aliphatic hydrocarbon group or an optionally substituted (hetero)aryl group, or wherein each of A 1 and A 2 , A 3 and A 4 , A 5 and A 6 , or, A 7 and A 8 , together comprise the necessary atoms to form a cyclic structure,
M 14 and M 15 are independently an optionally substituted aliphatic hydrocarbon group or an optionally substituted (hetero)aryl group, or wherein two of the M 14 , M 15 , A 5 or A 7 together comprise the necessary atoms to form at least one cyclic structure,
M 9 is one of the R d groups; and
the IR dye further comprises one or more counter ions in order to obtain an electrically neutral molecule.
3. The IR dye according to claim 2 , wherein M 1 and M 2 together include the necessary atoms to form an optionally substituted 5-membered ring.
4. The IR dye according to claim 2 , wherein the IR dye of Formula II, III, or IV has at least one anionic group or an acid group selected from the list consisting of —CO 2 H, —CONHSO 2 R h , —SO 2 NHCOR i , —SO 2 NHSO 2 R j , —PO 3 H 2 , —OPO 3 H 2 , —OSO 3 H, —SO 3 H, or —S—SO 3 H groups or their corresponding salts;
and R h , R i , and R j are independently an aryl or an alkyl group.
5. The IR dye according to claim 3 , wherein the IR dye of Formula II, III, or IV has at least one anionic group or an acid group selected from the list consisting of —CO 2 H, —CONHSO 2 R h , —SO 2 NHCOR i , —SO 2 NHSO 2 R j , —PO 3 H 2 , —OPO 3 H 2 , —OSO 3 H, —SO 3 H, or —S—SO 3 H groups or their corresponding salts;
and R h , R i , and R j are independently an aryl or an alkyl group.
6. The IR dye according to claim 4 , wherein each of the aliphatic hydrocarbon groups of M 3 , M 4 , or M 12 to M 15 of the IR dye is terminally substituted with at least one of the anionic groups or acid groups.
7. The IR dye according to claim 5 , wherein each of the aliphatic hydrocarbon groups of M 3 , M 4 , or M 12 to M 15 of the IR dye is terminally substituted with at least one of the anionic groups or acid groups.
8. A heat-sensitive lithographic printing plate precursor comprising a support having a hydrophilic surface or which is provided with a hydrophilic layer, and a coating provided thereon, wherein the coating includes an IR dye according to Formula I:
wherein
+ Y 1 =is represented by one of the following structures:
Y 2 —is represented by one of the following structures:
n is 0, 1, 2, or 3;
each of p and q is 0, 1, or 2;
R 1 and R 2 are independently an optionally substituted hydrocarbon group, or wherein two of the R 1 , R 2 , R d , or R a groups together include the necessary atoms to form a cyclic structure;
at least one of the R d groups is selected from the list consisting of:
—(N═CR 17 ) a —NR 5 —CO—R 4 ;
—(N═CR 17 ) b —NR 5 —SO 2 —R 6 ;
—(N═CR 17 ) c —NR 11 —SO—R 12 ;
—SO 2 —NR 15 R 16 ; and
—S—CH 2 —CR 7 (H) 1-d (R 8 ) d —NR 9 —COOR 18 ;
wherein
a, b, c, and d independently are 0 or 1;
R 17 is a hydrogen atom, an optionally substituted aliphatic hydrocarbon group, or an optionally substituted (hetero)aryl group, or wherein R 17 and R 5 , R 17 and R 11 together include the necessary atoms to form a cyclic structure;
R 4 is —OR 10 , —NR 13 R 14 , or —CF 3 ;
R 10 is an optionally substituted (hetero)aryl group or an optionally branched aliphatic hydrocarbon group;
R 13 and R 14 independently are a hydrogen atom, an optionally substituted aliphatic hydrocarbon group, or an optionally substituted (hetero)aryl group, or wherein R 13 and R 14 together include the necessary atoms to form a cyclic structure;
R 6 is an optionally substituted aliphatic hydrocarbon group or an optionally substituted (hetero)aryl group, —OR 10 , —NR 13 R 14 , or —CF 3 ;
R 5 is a hydrogen atom, an optionally substituted aliphatic hydrocarbon group, a SO 3 − group, a —COOR 18 group, or an optionally substituted (hetero)aryl group, or wherein R 5 together with at least one of R 10 , R 13 , and R 14 include the necessary atoms to form a cyclic structure;
R 11 , R 15 , and R 16 are independently a hydrogen atom, an optionally substituted aliphatic hydrocarbon group, or an optionally substituted (hetero)aryl group; or wherein R 15 and R 16 together include the necessary atoms to form a cyclic structure;
R 12 is an optionally substituted aliphatic hydrocarbon group or an optionally substituted (hetero)aryl group;
R 7 and R 9 independently are a hydrogen atom or an optionally substituted aliphatic hydrocarbon group;
R 8 is —COO − or —COOR 8′ ; wherein R 8′ is a hydrogen atom, an alkali metal cation, an ammonium ion, or a mono-, di-, tri- or tetra-alkyl ammonium ion;
R 18 is an optionally substituted (hetero)aryl group or an alpha-branched aliphatic hydrocarbon group;
R a and other R d groups are independently represented by a group selected from the list consisting of a hydrogen atom, a halogen atom, —R e , —OR f , —SR g , and —NR u R v ; wherein
R e , R f , R g , R u , and R v independently are an optionally substituted aliphatic hydrocarbon group or an optionally substituted (hetero)aryl group; and
the IR dye further comprises one or more counter ions in order to obtain an electrically neutral molecule.
9. The heat-sensitive precursor according to claim 8 , wherein the coating includes a photo-polymerizable composition.
10. The heat-sensitive precursor according to claim 8 , wherein the coating includes thermoplastic polymer particles dispersed in a hydrophilic binder.
11. The heat-sensitive precursor according to claim 8 , wherein the coating includes a switchable polymer which is capable of changing a polarity of the surface of the coating upon IR-radiation or heating from hydrophilic to hydrophobic or from hydrophobic to hydrophilic.
12. The heat-sensitive precursor according to claim 8 , wherein the coating includes a polymer which is soluble in an alkaline solution, and a solubility inhibiting compound which reduces the solubility of the coating in the alkaline solution, and wherein, upon IR-radiation or heating, the coating has an increased solubility in the alkaline solution.
13. A method for making a lithographic printing plate comprising the steps of:
providing the heat-sensitive lithographic printing plate precursor according to claim 8 ;
image-wise exposing the precursor to IR-radiation or heat; and
optionally developing the exposed precursor.
14. A method for making a lithographic printing plate comprising the steps of:
providing the heat-sensitive lithographic printing plate precursor according to claim 9 ;
image-wise exposing the precursor to IR-radiation or heat; and
optionally developing the exposed precursor.
15. A method for making a lithographic printing plate comprising the steps of:
providing the heat-sensitive lithographic printing plate precursor according to claim 10 ;
image-wise exposing the precursor to IR-radiation or heat; and
optionally developing the exposed precursor.
16. A method for making a lithographic printing plate comprising the steps of:
providing the heat-sensitive lithographic printing plate precursor according to claim 11 ;
image-wise exposing the precursor to IR-radiation or heat; and
optionally developing the exposed precursor.
17. A method for making a lithographic printing plate comprising the steps of:
providing the heat-sensitive lithographic printing plate precursor according to claim 12 ;
image-wise exposing the precursor to IR-radiation or heat; and
optionally developing the exposed precursor.
18. A method for making a lithographic printing plate comprising the steps of:
providing the heat-sensitive lithographic printing plate precursor according to claim 9 ;
image-wise exposing the precursor to IR-radiation or heat;
mounting the exposed precursor on a printing press; and
developing the precursor by supplying ink and/or fountain solution to the precursor.
19. A method for making a lithographic printing plate comprising the steps of:
providing the heat-sensitive lithographic printing plate precursor according to claim 10 ;
image-wise exposing the precursor to IR-radiation or heat;
mounting the exposed precursor on a printing press; and
developing the precursor by supplying ink and/or fountain solution to the precursor.