Method of making a photopolymer printing plate
View Patent ↗A method of making a lithographic printing plate includes the steps of: a) providing a lithographic printing plate precursor including (i) a support having a hydrophilic surface or which is provided with a hydrophilic layer, (ii) a coating on the support including a photopolymerizable layer, and, optionally, an intermediate layer between the photopolymerizable layer and the support, wherein the photopolymerizable layer includes a polymerizable compound and a polymerization initiator, b) image-wise exposing the coating in a plate setter, c) optionally, heating the precursor in a pre-heating unit, d) developing the precursor off-press in a gumming unit by treating the coating of the precursor with a gum solution, thereby removing the non-exposed areas of the photopolymerizable layer from the support, wherein the photopolymerizable layer further includes a polymer containing an acid group and a basic nitrogen-containing compound capable of neutralizing the acid group, or wherein the photopolymerizable layer further includes a polymer containing an acid group which is neutralized by a basic nitrogen-containing compound.
1. A method of making a lithographic printing plate including the steps of:
a) providing a lithographic printing plate precursor including a support having a hydrophilic surface or which is provided with a hydrophilic layer, a coating on the support including a photopolymerizable layer, and, optionally, an intermediate layer between the photopolymerizable layer and the support, wherein the photopolymerizable layer includes a polymerizable monomer or oligomer including an ethylenically unsaturated compound having at least one terminal ethylenic group and a polymerization initiator;
b) image-wise exposing the coating by a laser in a plate setter;
c) optionally, heating the precursor in a pre-heating unit;
d) developing the precursor by treating the coating of the precursor with a gum solution, thereby removing the non-exposed areas of the photopolymerizable layer from the support; wherein
the photopolymerizable layer further includes a polymer containing an acid group and a basic nitrogen-containing compound capable of neutralizing the acid group, or the photopolymerizable layer further includes a polymer containing an acid group which is neutralized by a basic nitrogen-containing compound; and
step (d) is carried out off-press in a gumming unit which is mechanically coupled to the plate setter and/or the pre-heating unit by a conveying device and the precursor is shielded from ambient light.
2. A method according to claim 1 , wherein the gum solution includes a surface protective compound which remains on the plate after step (d) as a layer including 0.005 to 20 g/m 2 of the surface protective compound.
3. A method according to claim 2 , wherein the surface protective compound is a film-forming hydrophilic polymer or surfactant.
4. A method according to claim 1 , wherein the gumming unit is provided with at least one roller for rubbing and/or brushing the coating during development.
5. A method according to claim 1 , wherein the basic nitrogen-containing compound has an amino group, an amidine group, or a guanidine group.
6. A method according to claim 5 , wherein the amino group is a tertiary amino group.
7. A method according to claim 1 , wherein the basic nitrogen-containing compound further includes a group having an ethylenically unsaturated bond.
8. A method according to claim 7 , wherein the group having the ethylenically unsaturated bond is a vinyl group or a (meth)acrylate group.
9. A method according to claim 1 , wherein the basic nitrogen-containing compound is a compound selected from the list consisting of:
N,N-dimethyl amino ethyl (meth)acrylate,
N,N-dimethyl amino propyl (meth)acrylate,
N,N-diethyl amino propyl (meth)acrylate,
N,N-diethyl amino ethyl (meth)acrylate,
N,N-diethyl amino propyl (meth)acrylamide,
N,N-dimethyl amino ethyl-N′-(meth)acryloyl carbamate,
N,N-diethyl amino-ethoxyethyl (meth)acrylate,
t-butyl amino ethyl (meth)acrylate,
N,N-diethyl amino ethanol,
N,N-dimethyl aniline,
N,N-dimethyl amino ethoxy ethanol,
2-amino-2-ethyl-1,3-propanediol,
triethanol amine,
2-N-morphorino ethanol, and
2-piperidino ethanol.
10. A method according to claim 1 , wherein the ratio of the amount of basic nitrogen-containing compound to the amount of acid groups present in the polymer ranges between 1 mol % and 200 mol %.
11. A method according to claim 10 , wherein the ratio ranges between 1 mol % and 100 mol %.
12. A method according to claim 1 , wherein the acid group of the polymer is a carboxylic acid group, a sulphonic acid group, an imide group, or a primary or secondary sulphonamide group.
13. A method according to claim 1 , wherein the polymer containing the acid group is a polymer or copolymer of (meth)acrylic acid.
14. A method according to claim 1 , wherein the dry coating weight of the photopolymerizable layer ranges between 0.6 g/m 2 and 2.2 g/m 2 .
15. A method according to claim 1 , wherein the gum solution has a pH-value ranging between 3 and 9.
16. A method according to claim 1 , wherein the laser emits violet light.
17. A method according to claim 1 , wherein the laser emits infrared light.
18. A method of making a lithographic printing plate including the steps of:
a) providing a lithographic printing plate precursor including a support having a hydrophilic surface or which is provided with a hydrophilic layer, a coating on the support including a photopolymerizable layer, and, optionally, an intermediate layer between the photopolymerizable layer and the support, wherein the photopolymerizable layer includes a polymerizable monomer or oligomer including an ethylenically unsaturated compound having at least one terminal ethylenic group and a polymerization initiator;
b) image-wise exposing the coating by a laser in a plate setter;
c) optionally, heating the precursor in a pre-heating unit;
d) developing and gumming the precursor in a single step consisting essentially of treating the coating of the precursor with a gum solution, thereby removing non-exposed areas of the coating from the support; wherein
the photopolymerizable layer further includes a polymer containing an acid group and a basic nitrogen-containing compound capable of neutralizing the acid group, or the photopolymerizable layer further includes a polymer containing an acid group which is neutralized by a basic nitrogen-containing compound; and
step (d) is carried out off-press in a gumming unit which is mechanically coupled to the plate setter and/or the pre-heating unit by a conveying device and the precursor is shielded from ambient light.
19. A method according to claim 18 , wherein the gum solution includes a surface protective compound which remains on the plate after step (d) as a layer including 0.005 to 20 g/m 2 of the surface protective compound.
20. A method according to claim 19 , wherein the surface protective compound is a film-forming hydrophilic polymer or surfactant.
21. A method according to claim 18 , wherein the gumming unit is provided with at least one roller for rubbing and/or brushing the coating during development.
22. A method according to claim 18 , wherein the basic nitrogen-containing compound has an amino group, an amidine group, or a guanidine group.
23. A method according to claim 22 , wherein the amino group is a tertiary amino group.
24. A method according to claim 18 , wherein the basic nitrogen-containing compound further includes a group having an ethylenically unsaturated bond.
25. A method according to claim 24 , wherein the group having the ethylenically unsaturated bond is a vinyl group or a (meth)acrylate group.
26. A method according to claim 18 , wherein the basic nitrogen-containing compound is a compound selected from the list consisting of:
N,N-dimethyl amino ethyl (meth)acrylate,
N,N-dimethyl amino propyl (meth)acrylate,
N,N-diethyl amino propyl (meth)acrylate,
N,N-diethyl amino ethyl (meth)acrylate,
N,N-diethyl amino propyl (meth)acrylamide,
N,N-dimethyl amino ethyl-N′-(meth)acryloyl carbamate,
N,N-diethyl amino-ethoxyethyl (meth)acrylate,
t-butyl amino ethyl (meth)acrylate,
N,N-diethyl amino ethanol,
N,N-dimethyl aniline,
N,N-dimethyl amino ethoxy ethanol,
2-amino-2-ethyl-1,3-propanediol,
triethanol amine,
2-N-morphorino ethanol, and
2-piperidino ethanol.
27. A method according to claim 18 , wherein the ratio of the amount of basic nitrogen-containing compound to the amount of acid groups present in the polymer ranges between 1 mol % and 200 mol %.
28. A method according to claim 27 , wherein the ratio ranges between 1 mol % and 100 mol %.
29. A method according to claim 18 , wherein the acid group of the polymer is a carboxylic acid group, a sulphonic acid group, an imide group, or a primary or secondary sulphonamide group.
30. A method according to claim 18 , wherein the polymer containing the acid group is a polymer or copolymer of (meth)acrylic acid.
31. A method according to claim 18 , wherein the dry coating weight of the photopolymerizable layer ranges between 0.6 g/m 2 and 2.2 g/m 2 .
32. A method according to claim 18 , wherein the gum solution has a pH-value ranging between 3 and 9.
33. A method according to claim 18 , wherein the laser emits violet light.
34. A method according to claim 18 , wherein the laser emits infrared light.