Method for making a negative-working lithographic printing plate precursor
View Patent ↗A method for making a heat-sensitive negative-working lithographic printing plate precursor including the steps of providing a support having a hydrophilic surface or which is provided with a hydrophilic layer, and applying onto the support a coating solution including an infrared absorbing agent, hydrophobic thermoplastic polymer particles, a hydrophilic binder, and a polymer including siloxane and/or perfluoroalkyl monomeric units.
1. A method for making a heat-sensitive negative-working lithographic printing plate precursor comprising the steps of:
providing a support having a hydrophilic surface or which is provided with a hydrophilic layer; and
applying onto the support a coating including an infrared absorbing agent, hydrophobic thermoplastic polymer particles, a hydrophilic binder, and a polymer having siloxane and/or perfluoroalkyl monomeric units; wherein
the polymer is a block-copolymer or graft-copolymer including a poly- or oligo(alkylene oxide) block and a block including siloxane and/or perfluoroalkyl monomeric units.
2. A method according to claim 1 , wherein the amount of the polymer in the coating is between 0.5 mg/m 2 and 60 mg/m 2 .
3. A method according to claim 1 , wherein the hydrophobic thermoplastic polymer particles have an average particle size in the range from 15 nm to 150 nm.
4. A method according to claim 1 , wherein the amount of the hydrophobic thermoplastic polymer particles in the coating is at least 70% by weight.
5. A method according to claim 1 , wherein the hydrophobic thermoplastic polymer particles include at least 0.1% of nitrogen.
6. A method according to claim 1 , wherein the coating further includes spacer particles having an average particle size between one to two times the thickness of the coating.
7. A method according to claim 6 , wherein the amount of spacer particles in the coating is between 8 mg/m 2 and 200 mg/m 2 .
8. A method according to claim 6 , wherein the spacer particles include organic particles selected from the group consisting of polymethylmethacrylate, polyolefins, halogenated polyolefins, cross-linked polysiloxanes, or copolymers thereof.
9. A method according to claim 6 , wherein the spacer particles include inorganic particles selected from the group consisting of metal oxides, metal hydroxides, zirconium containing particles, aluminiumsilicates, and metal salts.
10. A method for making a negative-working lithographic printing plate comprising the following steps:
providing a printing plate precursor obtained by the method according to claim 1 ;
exposing the precursor with infrared light thereby inducing coalescence of the thermoplastic polymer particles at exposed areas of the coating; and
processing the exposed precursor with an aqueous solution.
11. A method for making a negative-working lithographic printing plate comprising the following steps:
providing a printing plate precursor obtained by the method according to claim 1 ;
exposing the precursor with infrared light thereby inducing coalescence of the thermoplastic polymer particles at exposed areas of the coating; and
mounting the precursor on a printing press and developing it by supplying ink and/or fountain solution to the precursor.