US4468295A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for electrochemically roughening aluminum for printing plate supports
Assignee: Hoechst AG
•
Filing: 1983-05-02
•
Granted: 1984-08-28
•
Expires: 2003-05-02
Abstract
Abstract Disclosed is a process for electrochemically roughening aluminum or alloys thereof, in an aqueous electrolyte, under the action of an alternating current which is generated by superimposing at least two types of alternating current of different frequencies. The materials roughened in this manner are used as supports for radiation-sensitive reproduction coatings in the field of manufacturing offset-printing plates. Also disclosed are roughened aluminum supports and printing plates produced by the above process.
Inventors
- 👤 Engelbert Pliefke
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 16:38
CPC Classifications
C; C25; C25F; C25F3/00; C25F3/02; C25F3/04; B; B41; B41N; B41N3/00; B41N3/03; B41N3/034; Y; Y10; Y10S; Y10S204/00; Y10S204/09
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
101 words
A process for electrochemically roughening aluminum or alloys thereof for use as printing plate supports, comprising the step of electrochemically roughening aluminum or an aluminum alloy in an aqueous electrolyte with an alternating current generated by superimposing at least two types of alternating current having different frequencies, wherein said frequency or frequencies of said higher-frequency superimposing alternating current(s) is/are from 3 to 100 times greater than said frequency of said superimposing alternating current having the lowest frequency and the ratio of the ampli-tudes of said higher-frequency superimposing alternating current(s) to said lowest-frequency superimposing alternating current ranges between about 0.1 and 10.
Claim 2
Dependent Claim
101 words
A process for electrochemically roughening aluminum or alloys thereof for use as printing plate supports, comprising the step of electrochemically roughening aluminum or an aluminum alloy in an aqueous electrolyte with an alternating current generated by superimposing at least two types of alternating current having different frequencies, wherein said frequency or frequencies of said higher-frequency superimposing alternating current(s) is/are from 3 to 100 times greater than said frequency of said superimposing alternating current having the lowest frequency and the ratio of the ampli-tudes of said higher-frequency superimposing alternating current(s) to said lowest-frequency superimposing alternating current ranges between about 0.1 and 10.
Claim 3
Dependent Claim
16 words
A process as claimed in claim 1, wherein said ratio ranges between about 0.2 and 2.
Claim 4
Dependent Claim
34 words
A process as claimed in claim 1, wherein, when superimposing two types of alternating current, said lower-frequency superimposing alternating current comprises a rectangular shape and said higher-frequency superimposing alternating current comprises a sinusoidal shape.
Claim 5
Dependent Claim
14 words
A process as claimed in claim 1, wherein said aqueous electrolyte solution comprises HCl.
Claim 6
Dependent Claim
16 words
A process as claimed in claim 1, wherein said aqueous electrolyte solution comprises HNO 3 .
Claim 7
Dependent Claim
13 words
A process as claimed in claim 1, wherein said process is continuously performed.
Claim 8
Dependent Claim
13 words
A process as claimed in claim 1, wherein said process is discontinuously performed.
Claim 9
Dependent Claim
23 words
A process as claimed in claim 1, further comprising the step of anodically oxidizing said aluminum support to produce an aluminum oxide layer.
Claim 10
Dependent Claim
15 words
A process as claimed in claim 8, further comprising the step of post-treating said support.
Claim 11
Dependent Claim
20 words
A process as claimed in claim 9, wherein said post-treating step comprises a hydrophilizing treatment of said aluminum oxide layer.
Claim 12
Dependent Claim
15 words
A process as claimed in claim 10, wherein said hydrophilizing treatment comprises a chemical treatment.
Claim 13
Dependent Claim
15 words
A process as claimed in claim 10, wherein said hydrophilizing treatment comprises an electrochemical treatment.
Claim 14
Dependent Claim
23 words
A process as claimed in claim 8, further comprising the step of abrasively modifying said roughened surface prior to said anodically oxidizing step.
Claim 15
Dependent Claim
20 words
A process as claimed in claim 1, wherein the temperature of said electrolyte ranges from about 20° to 60° C.
Claim 16
Dependent Claim
13 words
A process as claimed in claim 1, wherein said support is uniformly roughened.
Claim 17
Dependent Claim
12 words
A roughened aluminum support produced by the process defined by claim 1.
Claim 18
Dependent Claim
60 words
A process for producing printing plates, comprising the steps of: providing an aluminum or aluminum alloy support; contacting said support with an aqueous electrolyte; applying to said support an alternating current generated by superimposing at least two types of alternating current having different frequencies to produce a roughened aluminum support; and coating said roughened support with a radiation-sensitive reproduction coating.
Claim 19
Dependent Claim
60 words
A process for producing printing plates, comprising the steps of: providing an aluminum or aluminum alloy support; contacting said support with an aqueous electrolyte; applying to said support an alternating current generated by superimposing at least two types of alternating current having different frequencies to produce a roughened aluminum support; and coating said roughened support with a radiation-sensitive reproduction coating.
Claim 20
Dependent Claim
11 words
A printing plate produced by the process defined in claim 17.
References Cited (Backward Citations)
GB879768A
Cited
US3193485A
Cited
US3330743A
Cited
GB1089657A
Cited
DE1496956A1
Cited
US3873318A
Cited
GB1400918A
Cited
US3963594A
Cited
US4140599A
Cited
US4087341A
Cited
US4072589A
Cited
US4301229A
Cited
US4229266A
Cited
GB2047274A
Cited
US4294672A
Cited
US4272342A
Cited
US4324841A
Cited
US4297184A
Cited
US4396468A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-08-28 | 1988-02-27 | 1988-08-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-08-28 | 1992-02-27 | 1992-08-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-08-28 | 1996-02-27 | 1996-08-28 | $7700.00 | Window Closed / Lapsed |