US 2003/0157433 A1Published application

On-press developable IR sensitive printing plates

AssigneeKodak Polychrome Graphics LLC

InventorsHans-Joachim Timpe, Friederike Von Gyldenfeldt

Life of this patent

Estimating the term…

Loading patent…

Abstract

The present invention relates to IR-sensitive compositions suitable for the manufacture of printing plates developable on-press. The IR-sensitive compositions comprise a first polymeric binder which does not comprise acidic groups having a pKa value≦8; a second polymeric binder comprising polyether groups; an initiator system; and a free radical polymerizable system comprising at least one member selected from unsaturated free radical polymerizable monomers, free radical polymerizable oligomers and polymers containing C═C bonds in the back bone and/or in the side chain groups. The initiator system includes (i) at least one compound capable of absorbing IR radiation; (ii) at least one compound capable of producing radicals selected from polyhaloalkyl-substituted compounds; and (iii) at least one polycarboxylic acid of formula R4—(CR5R6)r—Y—CH2COOH, wherein oxi<redii+1.6 eV, where oxi=oxidation potential of component (i) in eV, and redii=reduction potential of component (ii) in eV.

Claims36

Dependent claims

An IR-sensitive composition comprising:

(a) a first polymeric binder which does not comprise acidic groups having a pKa value less than or equal to 8;
(b) a second polymeric binder comprising polyether groups;
(c) an initiator system comprising:
(i) at least one compound capable of absorbing IR radiation selected from triarylamine dyes, thiazolium dyes, indolium dyes, oxazolium dyes, cyanine dyes, polyaniline dyes, polypyrrole dyes, polythiophene dyes and phthalocyanine pigments;
(ii) at least one compound capable of producing radicals selected from polyhaloalkyl-substituted compounds;
and
(iii) at least one polycarboxylic acid represented by the following formula I
R4—(CR5R6)r—Y—CH2COOH (I)
wherein Y is selected from the group consisting of O, S and NR7,
each of R4, R5 and R6 is independently selected from the group consisting
of hydrogen, C1-C4 alkyl, substituted or unsubstituted aryl, —COOH and NR8CH2COOH,
R7 is selected from the group consisting of hydrogen, C1-C6 alkyl,
—CH2CH2OH, and C1-C5 alkyl substituted with —COOH,
R8 is selected from the group consisting of —CH2COOH, —CH2OH and —(CH2)2N(CH2COOH)2 and r is 0, 1, 2 or 3, with the proviso that at least one of R4, R5, R6, R7 and R8 comprises a —COOH group or salts thereof;
and
(d) a free radical polymerizable system comprising at least one member selected from unsaturated free radical polymerizable monomers, oligomers which are free radical polymerizable and polymers containing C═C bonds in the back bone and/or in the side chain groups, wherein the following inequality is met:
oxi<redii+1.6 eV
with oxi=oxidation potential of component (i) in eV
redii=reduction potential of component (ii) in eV.

16 more elements

A printing plate precursor comprising:

(A) a substrate;
(B) a negative-working bottom layer applied onto the substrate and comprising an IR-sensitive composition comprising a polymeric binder comprising polyether groups, and
(C) an oxygen-impermeable top layer applied onto the bottom layer, wherein the printing plate precursor does not comprise an IR laser ablatable layer.

A method for preparing an on-press developable printing plate, the method comprising:

(A) providing a substrate;
(B) applying a negative-working bottom layer comprising an IR-sensitive composition onto the substrate to obtain a printing plate precursor, wherein the IR-sensitive composition comprises a polymeric binder comprising polyether groups;
(C) applying an oxygen-impermeable top layer onto the bottom layer;
(D) imagewise exposing the printing plate precursor obtained in step (B) to IR-radiation;
and
(E) developing on a press, wherein the method does not comprise a separate development step and does not comprise a separate heating step, and the printing plate does not comprise an IR laser ablatable layer.

3 more elements

Dependencies are inferred from the claim text.

Facts

Application: 10/066,874Filed 4 Feb 2002
Published: 21 Aug 2003
Term ends: Not estimatedThe source records don’t support an estimate.

Classification14 codes

B41C 1/1008
For lithographic printing; Master sheets for transferring a lithographic image to the forme: by removal or destruction of lithographic material on…
B41C 1/1016
By removal or destruction of lithographic material on the lithographic support, e.g. by laser or spark ablation; by the use of materials…
B41C 2201/02
Location, type or constituents of the non-imaging layers in lithographic printing formes: cover layers; Protective layers
B41C 2201/14
Location, type or constituents of the non-imaging layers in lithographic printing formes: characterised by macromolecular organic compounds, e.g.…