Patent US4400481A successfully refreshed from Google Patents.
US4400481A
Expired / Lapsed
US
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Finisher and preserver for lithographic plates
Assignee: Imperial Metal and Chemical Co
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Filing: 1982-08-20
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Granted: 1983-08-23
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Expires: 2002-08-20
Abstract
Abstract Finisher and preserver compositions are provided for desensitizing the non-image areas and protecting the image areas of lithographic plates of either the additive or the subtractive type that utilize substantially any type of exposure chemistry, the composition being useful for hand or machine finishing: they are also low in viscosity, are themselves unusually stable, preserve exposed plates for extended periods of storage time, and eliminate streaking on the plate to which they are applied to thereby substantially eliminate blinding problems during printing. Included in the finisher and preserver composition, which is a single phase aqueous system, are specific ratios of a blend of natural gum and synthetic hydrophilic resins, a preservative for the natural gum resin, a buffer system of phosphate and phosphoric acid, and a surfactant, with the balance being substantially entirely water.
Inventors
- 👤 Sunit S. Dixit
- 👤 William V. Stansky, Jr.
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 20:52
CPC Classifications
B; B41; B41N; B41N3/00; B41N3/08
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
270 words
A finisher and preserver for lithographic plates comprising a single-phase aqueous composition consisting essentially of: a blend of natural gum resin and synthetic hydrophilic resins in a total amount of between about 2 and 12 weight percent, based on the total weight of the aqueous composition, said resin blend including between about 1 and about 5 weight percent of the natural gum resin, between about 0.5 and about 5 weight percent of a cyclic amide synthetic hydrophilic resin, and between about 0.1 and about 2 weight percent of a polyacrylamide synthetic hydrophilic resin, all based on the total weight of the aqueous composition, wherein said resin blend includes a ratio of about 6 parts by weight of the natural gum resin, to about 3 parts by weight of the cyclic amide synthetic hydrophilic resin, to about 1 part by weight of the polyacrylamide synthetic hydrophilic resin, between about 0.05 and about 1 weight percent of a preservative for said natural resin, based on the total weight of the aqueous composition, a buffering system of phosphate and phosphoric acid, said buffering system being between about 0.5 and about 5 weight percent based on the total weight of the aqueous composition, a surfactant constituent in a total amount of between about 0.01 and about 0.2 weight percent, based on the total weight of the aqueous composition, and between about 85 and 95 weight percent water, based on the total weight of the aqueous composition, each of said blend of resins, preservatives, buffering system and surfactant constituent being in admixture with each other and being dissolved in said water in a single phase.
Claim 2
Dependent Claim
270 words
A finisher and preserver for lithographic plates comprising a single-phase aqueous composition consisting essentially of: a blend of natural gum resin and synthetic hydrophilic resins in a total amount of between about 2 and 12 weight percent, based on the total weight of the aqueous composition, said resin blend including between about 1 and about 5 weight percent of the natural gum resin, between about 0.5 and about 5 weight percent of a cyclic amide synthetic hydrophilic resin, and between about 0.1 and about 2 weight percent of a polyacrylamide synthetic hydrophilic resin, all based on the total weight of the aqueous composition, wherein said resin blend includes a ratio of about 6 parts by weight of the natural gum resin, to about 3 parts by weight of the cyclic amide synthetic hydrophilic resin, to about 1 part by weight of the polyacrylamide synthetic hydrophilic resin, between about 0.05 and about 1 weight percent of a preservative for said natural resin, based on the total weight of the aqueous composition, a buffering system of phosphate and phosphoric acid, said buffering system being between about 0.5 and about 5 weight percent based on the total weight of the aqueous composition, a surfactant constituent in a total amount of between about 0.01 and about 0.2 weight percent, based on the total weight of the aqueous composition, and between about 85 and 95 weight percent water, based on the total weight of the aqueous composition, each of said blend of resins, preservatives, buffering system and surfactant constituent being in admixture with each other and being dissolved in said water in a single phase.
Claim 3
Dependent Claim
29 words
The finisher and preserver composition of claim 1, wherein said resin blend includes gum arabic as the natural gum resin and a modified polyacrylamide as the polyacrylamide synthetic resin.
Claim 4
Dependent Claim
21 words
The finisher and preserver composition of claim 1, wherein said resin blend includes polyvinylpyrrolidone as the cyclic amide synthetic hydrophilic resin.
Claim 5
Dependent Claim
17 words
The finisher and preserver composition of claim 1, wherein said polyacrylamide synthetic hydrophilic resin is partially hydrolyzed.
Claim 6
Dependent Claim
34 words
The finisher and preserver composition of claim 1, wherein said resin blend includes polyvinylpyrrolidone as the cyclic amide synthetic hydrophilic resin and a partially hydrolyzed polyacrylamide synthetic resin as the polyacrylamide synthetic hydrophilic resin.
Claim 7
Dependent Claim
24 words
The finisher and preserver composition of claim 1, wherein said resin blend includes gum arabic, polyvinyl pyrollidone, and a partially hydrolyzed polyacrylamide synthetic resin.
Claim 8
Dependent Claim
25 words
The finisher and preserver composition of claim 1, wherein said resin blend comprises between about 3 and 8 weight percent of the total aqueous composition.
Claim 9
Dependent Claim
18 words
The finisher and preserver composition of claim 1, wherein said preservative is sodium benzoate at a growth-inhibiting concentration.
Claim 10
Dependent Claim
18 words
The finisher and preserver composition of claim 1, wherein said buffering system includes trisodium phosphate and phosphoric acid.
Claim 11
Dependent Claim
23 words
The finisher and preserver composition of claim 1, wherein said buffering system maintains the composition at a pH between about 4.1 and 4.5.
Claim 12
Dependent Claim
20 words
The finisher and preserver composition of claim 1, wherein said buffering system includes monosodium phosphate, trisodium phosphate, and phosphoric acid.
Claim 13
Dependent Claim
37 words
The finisher and preserver composition of claim 1, wherein said buffering system includes between about 0.3 and 2 weight percent, based on the total weight of the aqueous composition, of each of trisodium phosphate and phosphoric acid.
Claim 14
Dependent Claim
27 words
The finisher and preserver composition of claim 1, wherein said buffering system includes monosodium phosphate, trisodium phosphate and phosphoric acid at a weight ratio of 1:3:3, respectively.
Claim 15
Dependent Claim
41 words
The finisher and preserver composition of claim 1, wherein said surfactant constituent includes generally equal parts by weight of an ethoxylate and of a polyether, and the total concentration of the surfactant constituent is between about 0.02 and 0.1 weight percent.
Claim 16
Dependent Claim
18 words
The finisher and preserver composition of claim 1, wherein said surfactant constituent includes a modified linear alcohol ethoxylate.
Claim 17
Dependent Claim
26 words
The finisher and preserver composition of claim 1, wherein said surfactant constituent includes a blend of a modified linear alcohol ethoxylate and a modified aliphatic polyether.
Claim 18
Dependent Claim
21 words
The finisher and preserver composition of claim 1, wherein said composition has a viscosity between about 20 and about 25 centipoises.
References Cited (Backward Citations)
US4033919A
Cited
GB1495522A
Cited
US4078493A
Cited
US3988495A
Cited
GB1552833A
Cited
GB2010298A
Cited
US4253999A
Cited
US4213887A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1986-08-22 | 1987-02-21 | 1987-08-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-08-22 | 1991-02-21 | 1991-08-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-08-22 | 1995-02-21 | 1995-08-23 | $7700.00 | Window Closed / Lapsed |