Printing plates using binder resins having polyethylene oxide segments
View Patent ↗The present invention relates to a polymerizable coating composition suitable for the manufacture of printing plates, which may be developable on-press. The coating composition comprises (i) a polymerizable compound and (ii) a polymeric binder comprising polyethylene oxide segments, wherein the polymeric binder is selected from the group consisting of at least one graft copolymer comprising a main chain polymer and polyethylene oxide side chains, a block copolymer having at least one polyethylene oxide block and at least one non-polyethylene oxide block, and a combination thereof. The invention is also directed to an imageable element comprising a substrate and the polymerizable coating composition.
1. A method for preparing a printing plate, the method comprising
providing a substrate;
applying a negative-working layer comprising a radiation sensitive composition onto the substrate, wherein the radiation sensitive composition is ink receptive upon exposure to infrared imaging radiation and comprises an infrared-radiation absorber, a free radical initiator system comprising an electron acceptor and a coinitiator capable of donating electrons, donating hydrogen atoms, or forming a hydrocarbon radical, a polymerizable compound, and between about 10 and about 90 weight percent of a polymeric binder, wherein the polymeric binder comprises at least one graft copolymer comprising a main chain polymer and polyethylene oxide side chains, or a combination of said graft copolymer with a block copolymer having at least one polyethylene oxide block;
imagewise exposing the negative-working layer to infrared radiation; and
developing the negative-working layer on a press by contacting with ink and/or fountain solution to produce a printing plate, wherein the method does not comprise a separate development step.
2. The method of claim 1 , wherein the imagewise exposing step is carried out using an infrared laser.
3. A method for preparing a printing plate, the method comprising
providing a substrate;
applying a negative-working layer comprising a radiation sensitive composition onto the substrate, wherein the radiation sensitive composition is ink receptive upon exposure to ultraviolet imaging radiation and comprises an ultraviolet-radiation absorber, a free radical initiator system comprising an electron acceptor and a coinitiator capable of donating electrons, donating hydrogen atoms, or forming a hydrocarbon radical, a polymerizable compound, and between about 10 and about 90 weight percent of a polymeric binder, wherein the polymeric binder comprises at least one graft copolymer comprising a main chain polymer and polyethylene oxide side chains, or a combination of said graft copolymer with a block copolymer having at least one polyethylene oxide block;
imagewise exposing the negative-working layer to ultraviolet radiation; and
developing the negative-working layer on a press by contacting with ink and/or fountain solution to produce a printing plate, wherein the method does not comprise a separate development step.
4. A lithographic printing plate precursor comprising:
a substrate; and
a polymerizable composition coated onto the substrate, the polymerizable composition being ink receptive upon exposure to imaging ultraviolet or infrared radiation and comprising a polymerizable compound and between about 10 and about 90 weight percent of a polymeric binder;
wherein the polymeric binder is a graft copolymer having a hydrophobic backbone and a plurality of pendant groups comprising polyethylene oxide segments, the pendent groups being represented by
-Q-W—Y
wherein:
Q is a difunctional connecting group; and
the segment —W—Y is represented by —(O—CH 2 CH 2 ) n —OR 16 wherein R 16 is an alkyl of 1-5 carbon atoms, and n is from about 12 to about 75,
wherein the polymerizable composition also comprises a free radical initiator system comprising an electron acceptor and a coinitiator capable of donating electrons, donating hydrogen atoms, or forming a hydrocarbon radical.
5. The lithographic printing plate of claim 4 wherein R 16 is methyl.
6. A lithographic printing plate precursor comprising:
a substrate; and
a polymerizable composition coated onto the substrate, the polymerizable composition being ink receptive upon exposure to imaging ultraviolet or infrared radiation and comprising a polymerizable compound and between about 10 and about 90 weight percent of a polymeric binder;
wherein the polymeric binder is a graft copolymer comprising units represented by
wherein n is from about 12 to about 75, and
wherein the polymerizable composition also comprises a free radical initiator system comprising an electron acceptor and a coinitiator capable of donating electrons, donating hydrogen atoms, or forming a hydrocarbon radical.
7. A lithographic printing plate precursor comprising:
a substrate; and
a polymerizable composition coated onto the substrate, the polymerizable composition being ink receptive upon exposure to imaging ultraviolet or infrared radiation and comprising a polymerizable compound and between about 10 and about 90 weight percent of a polymeric binder;
wherein the polymeric binder is a graft copolymer comprising units represented by
wherein n is from about 12 to about 75,
wherein the polymerizable composition also comprises a free radical initiator system comprising an electron acceptor and a coinitiator capable of donating electrons, donating hydrogen atoms, or forming a hydrocarbon radical.