Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
261 words
An image-bearing lithographic printing plate having in the form of a thin coating deposited from solution on the non-image areas of the plate a desensitizing material comprising an active polymer component selected from the group consisting of (a) a polyacrylamide-based polymer wherein from about 5 to about 70 percent of the carbonyl sites are carboxyl groups and the balance of said sites are amide moieties; (b) a physical blend comprised of from about 95 to about 30 weight percent polyacrylamide and from about 5 to about 70 percent polyacrylic acid or an alkali metal or ammonium salt thereof; (c) a physical blend comprised of polyacrylamide, or polyacrylic acid or an alkali metal or ammonium salt thereof, and at least one polyacrylamide-based polymer as described in (a), said polymers being employed in proportions such that of the total carbonyl sites present in the blend, from about 5 to about 70 percent are carboxyl groups and the balance are amide moieties; (d) a mixture of any two or more of the foregoing (a)-(c); the weight average molecular weight of each of said polyacrylamide-based polymer, polyacrylamide, and polyacrylic acid or salt thereof being in the range of from about 10,000 to about 500,000; and (e) a co-mixture of one or more of the foregoing (a)-(d) with up to 30 weight percent hydroxypropyl methylcellulose based on the total weight of the co-mixture, said hydroxypropyl methylcellulose being of a type which produces a 2 weight percent solution having a viscosity of from about 1 to about 100 cP when measured according to ASTM Method D 2363-72.
Claim 2
Dependent Claim
261 words
An image-bearing lithographic printing plate having in the form of a thin coating deposited from solution on the non-image areas of the plate a desensitizing material comprising an active polymer component selected from the group consisting of (a) a polyacrylamide-based polymer wherein from about 5 to about 70 percent of the carbonyl sites are carboxyl groups and the balance of said sites are amide moieties; (b) a physical blend comprised of from about 95 to about 30 weight percent polyacrylamide and from about 5 to about 70 percent polyacrylic acid or an alkali metal or ammonium salt thereof; (c) a physical blend comprised of polyacrylamide, or polyacrylic acid or an alkali metal or ammonium salt thereof, and at least one polyacrylamide-based polymer as described in (a), said polymers being employed in proportions such that of the total carbonyl sites present in the blend, from about 5 to about 70 percent are carboxyl groups and the balance are amide moieties; (d) a mixture of any two or more of the foregoing (a)-(c); the weight average molecular weight of each of said polyacrylamide-based polymer, polyacrylamide, and polyacrylic acid or salt thereof being in the range of from about 10,000 to about 500,000; and (e) a co-mixture of one or more of the foregoing (a)-(d) with up to 30 weight percent hydroxypropyl methylcellulose based on the total weight of the co-mixture, said hydroxypropyl methylcellulose being of a type which produces a 2 weight percent solution having a viscosity of from about 1 to about 100 cP when measured according to ASTM Method D 2363-72.
Claim 3
Dependent Claim
41 words
The coated plate of claim 1 wherein the weight average molecular weight of each of the polyacrylamide-based polymer, the polyacrylamide, and/or the polyacrylic acid or salt thereof comprising the coating is in the range of from about 25,000 to about 300,000.
Claim 4
Dependent Claim
37 words
The coated plate of claim 2 in which the active polymer in the coating is the co-mixture of item (e) and hydroxypropyl methylcellulose comprises from about 10 to about 25 weight percent of the active polymer component.
Claim 5
Dependent Claim
26 words
The coated plate of claim 1 wherein of the carbonyl sites in the active polymer component, from about 5 to about 50 percent are carboxyl groups.
Claim 6
Dependent Claim
20 words
The coated plate of claim 4 wherein of the carbonyl sites, from about 5 to 25 percent are carboxyl groups.
Claim 7
Dependent Claim
41 words
The coated plate of claim 4 wherein the weight average molecular weight of each of the polyacrylamide-based polymer, the polyacrylamide, and/or the polyacrylic acid or salt thereof comprising the coating is in the range of from about 25,000 to about 300,000.
Claim 8
Dependent Claim
37 words
The coated plate of claim 4 wherein the active polymer component in the coating is the co-mixture of item (e), and hydroxypropyl methylcellulose comprises from about 10 to about 25 weight percent of the active polymer component.
Claim 9
Dependent Claim
77 words
The coated plate of claim 1 wherein the coating contains, in addition, one or more of: a compound selected from the group consisting of (1) phosphoric acid and (2) alkali metal phosphates and ammonium phosphates and mixtures thereof; a chromium-anion providing agent, or a metal nitrate, said metal nitrate being selected from those metal nitrates, the corresponding hydroxide compound of which has a solubility product in water of from about 10 -5 to about 10 -35 .
Claim 10
Dependent Claim
24 words
The coated plate of claim 8 wherein the metal nitrate is magnesium or zinc nitrate, and wherein the chromiun-anion providing agent is ammonium bichromate.
Claim 11
Dependent Claim
59 words
The coated plate of claim 9 wherein of the carbonyl sites in the active polymer component, from about 5 to about 50 percent are carboxyl groups, and wherein the weight average molecular weight of each of the polyacrylamide-based polymer, the polyacrylamide, and/or the polyacrylic acid or salt thereof is within the range of from about 25,000 to about 300,000.