US3887447A - Process of electrograining aluminium - Google Patents

Process of electrograining aluminium Download PDF

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Publication number
US3887447A
US3887447A US401257A US40125773A US3887447A US 3887447 A US3887447 A US 3887447A US 401257 A US401257 A US 401257A US 40125773 A US40125773 A US 40125773A US 3887447 A US3887447 A US 3887447A
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electrolyte
gms
aluminium
electrograining
hydrochloric acid
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US401257A
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Peter Geoffrey Sheasby
Alan Martin Smith
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Alcan Research and Development Ltd
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Alcan Research and Development Ltd
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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41N—PRINTING PLATES OR FOILS; MATERIALS FOR SURFACES USED IN PRINTING MACHINES FOR PRINTING, INKING, DAMPING, OR THE LIKE; PREPARING SUCH SURFACES FOR USE AND CONSERVING THEM
    • B41N3/00—Preparing for use and conserving printing surfaces
    • B41N3/08—Damping; Neutralising or similar differentiation treatments for lithographic printing formes; Gumming or finishing solutions, fountain solutions, correction or deletion fluids, or on-press development
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41N—PRINTING PLATES OR FOILS; MATERIALS FOR SURFACES USED IN PRINTING MACHINES FOR PRINTING, INKING, DAMPING, OR THE LIKE; PREPARING SUCH SURFACES FOR USE AND CONSERVING THEM
    • B41N3/00—Preparing for use and conserving printing surfaces
    • B41N3/03—Chemical or electrical pretreatment
    • B41N3/034—Chemical or electrical pretreatment characterised by the electrochemical treatment of the aluminum support, e.g. anodisation, electro-graining; Sealing of the anodised layer; Treatment of the anodic layer with inorganic compounds; Colouring of the anodic layer
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25F—PROCESSES FOR THE ELECTROLYTIC REMOVAL OF MATERIALS FROM OBJECTS; APPARATUS THEREFOR
    • C25F3/00—Electrolytic etching or polishing
    • C25F3/02—Etching
    • C25F3/04—Etching of light metals

Definitions

  • the present invention relates to improvements in the process of electrograining (electroetching) aluminium.
  • Aluminium is commonly used for the production of lithographic printing plates. For this purpose it is desirable that it should have a roughened surface characterised by the presence of very fine pits.
  • hydrochloric acid electrolyte generally incorporates 2-20 gms hydrochloric acid per litre.
  • the preparation of aluminium for use in lithographic printing comprises a three-stage process involving degreasing and pretreatment (usually etching in sodium hydroxide-based solutions) followed by electrograining and anodising.
  • electrograining is conventionally carried out by applying alternating current to the aluminium whilst immersed in dilute aqueous hydrochloric acid. Since it is economically necessary to wash the aluminium in normal tap water (deionised water being too expensive for wash purposes) after the pretreatment stages, it is inevitable that the electrograining electrolyte will become progressively contaminated by whatever ions may be present in the wash water, carried over on the surface of the aluminium. Most natural waters contain more than parts per million sulphate ion.
  • a very suitable concentration of orthophosphoric acid is 5 l0 gms/litre.
  • EXAMPLE 1 A hydrochloric acid, containing 6 gms hydrochloric acid per litre, electrolyte was made up with deionised water 1 litre) and 5 gms orthophosphoric acid per litre was added.
  • EXAMPLE 2 A 8 gms per litre hydrochloric acid electrolyte was made up, using tap water containing about ppm. of sulphate ion, and 8 gms per litre phosphoric acid was added. When panels of 99.7 percent aluminium were processed under the same conditions as Example 1, a finely pitted surface with pits ranging from l-5 microns in diameter were produced. A similar electrolyte was then made up without the addition of phosphoric acid and this produced a relatively irregular and coarsely pitted surface with pit sizes ranging from about 10 to 30 microns.
  • EXAMPLE 3 Trials were carried out in a 50-gallon tank containing 8 gms/litre hydrochloric acid electrolyte made up with tap water containing about 100 ppm. of sulphate ion.
  • a 99.7 percent aluminium sheet 480 mm X mm (19 in. X 5 in.) electrograined at room temperature at a constant current of amps (about 200 amps/sq. ft. at the treated face of the panel) with the applied ac. voltage rising from 10 to 12 volts over the 2-minute electrograining period, produced a surface with pits up to 20 by 30 microns in size.
  • both electrodes may be formed of aluminium plates to be electrograined.
  • the process may also be carried out on a continuous scale.
  • a continuous strip of aluminium is drawn through a two-compartment cell, in each of which is a counterelectrode connected to an a.c. source, so that current flows between the counterelectrodes through the aluminium strip which is passed through an aperture in the partition between the two compartments and through the electrolyte between the electrodes and the adjacent portion of the strip.

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  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Printing Plates And Materials Therefor (AREA)

Abstract

In a process for electrograining aluminium by subjecting the aluminium to alternating current whilst immersed in an aqueous electrolyte containing 2 - 20 gms/litre hydrochloric acid the electrolyte is stabilised against the presence of sulphate ion contamination and the pit size is controlled to a value below about 10 microns by the addition to the electrolyte of defined quantities of phosphoric acid or chromic acid. Both for operational reasons and for avoidance of health hazards it is preferred to employ phosphoric acid in an amount of about 5 - 10 gms/litre.

Description

United States Patent [191 Sheasby et al.
[ June 3, 1975 PROCESS OF ELECTROGRAINING ALUMINIUM [75] Inventors: Peter Geoffrey Sheasby; Alan Martin Smith, both of Banbury, England [22] Filed: Sept. 27, 1973 [21] Appl. No.: 401,257
[52] US. Cl. 204/129.4; 204/l29.75; 204/129.95 [51] Int. Cl C23b 3/02 [58] Field of Search 204/1294, 129.9, 129.95,
[56] References Cited UNITED STATES PATENTS 2,721,835 10/1955 Axtell 204/12995 3,477,929 11/1969 Namikata et al. 204/12995 3,755,116 8/1973 Teral et al. 204/129.95
FOREIGN PATENTS OR APPLICATIONS 1,202,030 8/1970 United Kingdom 204/l29.95
831,954 4/"1960 United Kingdom 204/1294 1,441,928 5/1966 France 529,755 6/1955 Italy 204/ 129.4
Primary ExaminerT. Tung Attorney, Agent, or Firm-Cooper, Dunham, Clark, Griffin & Moran ABSTRACT In a process for electrograining aluminium by subjecting the aluminium to alternating current whilst immersed in an aqueous electrolyte containing 2 20 gms/litre hydrochloric acid the electrolyte is stabilised against the presence of sulphate ion contamination and the pit size is controlled to a value below about 10 microns by the addition to the electrolyte of defined quantities of phosphoric acid or chromic acid. Both for operational reasons and for avoidance of health hazards it is preferred to employ phosphoric acid in an amount of about 5 1O gms/litre.
2 Claims, No Drawings PROCESS OF ELECTROGRAINING ALUMINIUM The present invention relates to improvements in the process of electrograining (electroetching) aluminium.
Aluminium is commonly used for the production of lithographic printing plates. For this purpose it is desirable that it should have a roughened surface characterised by the presence of very fine pits.
One known way of producing a desirable fine, uniformly pitted surface with randomly oriented pits is by an electrograining technique, in which the aluminium is subjected to alternating current when immersed in dilute hydrochloric acid. The hydrochloric acid electrolyte generally incorporates 2-20 gms hydrochloric acid per litre.
In the alternating current electrograining of aluminium sheet in hydrochloric acid as a pretreatment for the production of lithographic plates it is conventional to employ a current density in the range of 20 to 60 amps/sq. ft. (2 to 6 amps/dm for a period of 4 to 15 minutes. The charge input involved is generally in the range of 15,000 50,000 coulombs/sq. ft.
The above conditions are typical for batch processes. Where a continuous process is employed, i.e., where moving strip material is moved past stationary electrodes, current densities of the order of 100 1,000 amps/sq. ft. (l0 100 amps/dm may be employed for treatment times of /2 3 minutes.
Whilst coarsely-pitted electrograined surfaces can readily be obtained with such electrolyte, it is found that considerable care must be exercised in order to obtain a finely pitted surface (pits below microns in diameter). In particular, it is found that the presence of sulphate ion in the electrolyte will usually lead to a coarsely pitted surface, in which the pits are larger than is desirable for optimum performance for lithographic purposes. Although it is possible to start up the process with electrolyte made up with deionised water, it is inevitable that the electrolyte will become increasingly contaminated with sulphate and other ions carried over from earlier stages of the process.
As conventionally performed the preparation of aluminium for use in lithographic printing comprises a three-stage process involving degreasing and pretreatment (usually etching in sodium hydroxide-based solutions) followed by electrograining and anodising. As explained above, electrograining is conventionally carried out by applying alternating current to the aluminium whilst immersed in dilute aqueous hydrochloric acid. Since it is economically necessary to wash the aluminium in normal tap water (deionised water being too expensive for wash purposes) after the pretreatment stages, it is inevitable that the electrograining electrolyte will become progressively contaminated by whatever ions may be present in the wash water, carried over on the surface of the aluminium. Most natural waters contain more than parts per million sulphate ion.
It has been shown by practical printing trials that very finely grained surfaces lead to extended plate life and better image definition in lithographic printing. We have however found that contamination of the hydrochloric acid electrograining electrolyte by more than about 10 15 parts per million sulphate ion leads to a much more irregular and coarsely pitted surface, with the result that lithographic printing plates of relatively poor quality result from electrolyte made up from tap present in an amount of 1.5 l5 gms/litre, whilst chromic acid (calculated as CrO may be present in an amount of L5 2.0 gms/litre.
It is greatly preferred to employ phosphoric acid to chromic acid, for reasons of economics, lesser criticality of concentration and far lower health hazards involved.
With 'both materials it is found desirable to hold down the quantity of alkali metal ion, since this is also found to lead to the formation of large, irregular pits during electrograining, although it is tolerable in much larger proportions than is sulphate ion. A very suitable concentration of orthophosphoric acid is 5 l0 gms/litre.
The invention is hereinafter further described with reference to the following examples:
EXAMPLE 1 A hydrochloric acid, containing 6 gms hydrochloric acid per litre, electrolyte was made up with deionised water 1 litre) and 5 gms orthophosphoric acid per litre was added. mm X 50 mm (3 in. X 2 in.) panels of 99.7 percent aluminium were electrograined in this solution at room temperature with a 75 mm X 75 mm (3 in. X 3 in.) graphite counterelectrode placed 50 mm (2 in.) away from it. An ac voltage of 8 volts was applied for 6 minutes and a finely pitted surface was produced with the average pit size about 3 microns. Varying the hydrochloric acid concentration between 6 gms and 9 gms per litre had no effect on the fineness of the surface produced, although the current passing varied from about 4 amps to 5 amps under these conditions (about 70 amps/sq. ft. at the treated face of the panel).
EXAMPLE 2 A 8 gms per litre hydrochloric acid electrolyte was made up, using tap water containing about ppm. of sulphate ion, and 8 gms per litre phosphoric acid was added. When panels of 99.7 percent aluminium were processed under the same conditions as Example 1, a finely pitted surface with pits ranging from l-5 microns in diameter were produced. A similar electrolyte was then made up without the addition of phosphoric acid and this produced a relatively irregular and coarsely pitted surface with pit sizes ranging from about 10 to 30 microns.
EXAMPLE 3 Trials were carried out in a 50-gallon tank containing 8 gms/litre hydrochloric acid electrolyte made up with tap water containing about 100 ppm. of sulphate ion. A 99.7 percent aluminium sheet 480 mm X mm (19 in. X 5 in.), electrograined at room temperature at a constant current of amps (about 200 amps/sq. ft. at the treated face of the panel) with the applied ac. voltage rising from 10 to 12 volts over the 2-minute electrograining period, produced a surface with pits up to 20 by 30 microns in size. After addition of 8 gms/litre orthophosphoric acid to the same electrolyte, processing a similar panel under the same con- 3 ditions gave a surface with pits ranging from 1 5 microns in size.
In these tests the aluminium plates were connected as one electrode of the system with a graphite electrode. However both electrodes may be formed of aluminium plates to be electrograined. The process may also be carried out on a continuous scale. A continuous strip of aluminium is drawn through a two-compartment cell, in each of which is a counterelectrode connected to an a.c. source, so that current flows between the counterelectrodes through the aluminium strip which is passed through an aperture in the partition between the two compartments and through the electrolyte between the electrodes and the adjacent portion of the strip. By using this method, which has long been known for continuous anodising, contact between the strip and an electrode is avoided and arcing problems are avoided.
We claim:
1. In the process of electrograining aluminum for the production of lithographic printing plates which comprises subjecting the aluminum to alternating current while immersed in an aqueous electrolyte containing 2 20 gms/liter hydrochloric acid the improvement which comprises the addition to the electrolyte of L5 l5 gms/liter phosphoric acid whereby to maintain the pit size below about l0 microns in the presence of contaminant sulphate ion in the electrolyte.
2. The process of claim 1 wherein the aqueous electrolyte contains 5 l0 gms/liter phosphoric acid.

Claims (2)

1. IN THE PROCESS OF ELECTROGRAINING ALUMINUM FOR THE PRODUCTION OF LITHOGRAPHIC PRINTING PLATES WHICH COMPRISES SUBJECTING THE ALUMINUM TO ALTERNATING CURRENT WHILE IMMERSED IN AN AQUEOUS ELECTROLYTE CONTAINING 2-20 GMS/LITER HYDROCHLORIC ACID THE IMPROVEMENT WHICH COMPRISES THE ADDITION TO THE ELECTROLYTE OF 1.5 - 15 GMS/LITER PHOSPHORIC ACID WHEREBY TO MAINTAIN THE PIT SIZE BELOW ABOUT MICRONS IN THE PRESENCE OF CONTAMINANT SULPHATE ION IN THE ELECTROLYTE.
1. In the process of electrograining aluminum for the production of lithographic printing plates which comprises subjecting the aluminum to alternating current while immersed in an aqueous electrolyte containing 2 - 20 gms/liter hydrochloric acid the improvement which comprises the addition to the electrolyte of 1.5 - 15 gms/liter phosphoric acid whereby to maintain the pit size below about 10 microns in the presence of contaminant sulphate ion in the electrolyte.
US401257A 1971-07-09 1973-09-27 Process of electrograining aluminium Expired - Lifetime US3887447A (en)

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GB3243871A GB1392191A (en) 1971-07-09 1971-07-09 Process for electrograining aluminium
CA172,192A CA1009606A (en) 1971-07-09 1973-05-24 Process of electrograining aluminium

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CH (1) CH566401A5 (en)
DE (1) DE2327764B2 (en)
FR (1) FR2237438A5 (en)
GB (1) GB1392191A (en)
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SE (1) SE381683B (en)

Cited By (32)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4072589A (en) * 1977-04-13 1978-02-07 Polychrome Corporation Process for electrolytic graining of aluminum sheet
US4087341A (en) * 1975-11-06 1978-05-02 Nippon Light Metal Research Laboratory Ltd. Process for electrograining aluminum substrates for lithographic printing
US4140599A (en) * 1975-06-04 1979-02-20 Fujitsu Limited Process for producing porous aluminum anode element
US4198278A (en) * 1977-06-10 1980-04-15 Toyo Aluminum Kabushiki Kaisha Method for producing anode aluminum foils for electrolytic condensers
US4279715A (en) * 1980-09-15 1981-07-21 Sprague Electric Company Etching of aluminum capacitor foil
US4279714A (en) * 1980-09-15 1981-07-21 Sprague Electric Company AC Etching of aluminum capacitor
US4294672A (en) * 1979-05-30 1981-10-13 Fuji Photo Film Co., Ltd. Method for preparing a support for a lithographic printing plate
US4301229A (en) * 1978-03-27 1981-11-17 Fuji Photo Film Co., Ltd. Electrolytically grained aluminum support for making a lithographic plate and presensitized lithographic printing plate
US4332651A (en) * 1981-05-20 1982-06-01 Sprague Electric Company AC Etching of aluminum capacitor foil
US4336113A (en) * 1981-06-26 1982-06-22 American Hoechst Corporation Electrolytic graining of aluminum with hydrogen peroxide and nitric or hydrochloric acid
US4427506A (en) 1982-09-24 1984-01-24 Sprague Electric Company AC Etching of aluminum capacitor foil
US4477317A (en) * 1977-05-24 1984-10-16 Polychrome Corporation Aluminum substrates useful for lithographic printing plates
USRE31743E (en) * 1980-09-15 1984-11-20 Sprague Electric Company AC Etching of aluminum capacitor foil
US4547275A (en) * 1984-02-03 1985-10-15 Showa Aluminum Kabushiki Kaisha Process for treating surface of aluminum foil for use as electrode of electrolytic capacitors
US4576686A (en) * 1983-09-27 1986-03-18 Fuji Photo Film Co., Ltd. Process for producing aluminum support for lithographic printing plates
US4581996A (en) * 1982-03-15 1986-04-15 American Hoechst Corporation Aluminum support useful for lithography
US4600482A (en) * 1984-04-25 1986-07-15 Hoechst Aktiengesellschaft Process for the electrochemical roughening of aluminum for use as printing plate supports, in an aqueous mixed electrolyte
US4618405A (en) * 1984-04-25 1986-10-21 Hoechst Aktiengesellschaft Process for the electrochemical roughening of aluminum for use as printing plate supports, in an aqueous mixed electrolyte
US4626328A (en) * 1984-04-25 1986-12-02 Hoechst Aktiengesellschaft Process for the electrochemical roughening of aluminum for use as printing plate supports, in an aqueous mixed electrolyte
US4655136A (en) * 1983-02-14 1987-04-07 Hoechst Aktiengesellschaft Sheet material of mechanically and electrochemically roughened aluminum, as a support for offset-printing plates
US4661219A (en) * 1985-02-06 1987-04-28 Hoechst Aktiengesellschaft Process for the electrochemical roughening of aluminum for use in printing plate supports
US4666576A (en) * 1985-02-06 1987-05-19 Hoechst Aktiengesellschaft Process for the electrochemical roughening of aluminum for use in printing plate supports
US4671859A (en) * 1985-09-20 1987-06-09 Hoeschst Aktiengesellschaft Process for the electrochemical graining of aluminum for use as printing plate supports
EP0268790A2 (en) 1986-10-17 1988-06-01 Hoechst Aktiengesellschaft Process for electrochemically modifying support materials of aluminum or aluminum alloys, which have been grained in a multi-stage process and use of these materials in the manufacture of offset-printing plates
US4824535A (en) * 1986-10-17 1989-04-25 Hoechst Aktiengesellschaft Process for the electrochemical graining of aluminum for use in printing plate supports
US4840713A (en) * 1987-05-26 1989-06-20 Hoechst Aktiengesellschaft Process for the electrochemical roughening of aluminum for use in printing plate supports
US4976198A (en) * 1979-08-16 1990-12-11 Fuji Photo Film Co., Ltd. Grain structure for lithographic printing plate supports
US5152877A (en) * 1989-10-13 1992-10-06 Fuji Photo Film Co., Ltd. Method for producing support for printing plate
US5156723A (en) * 1990-01-19 1992-10-20 Hoechst Aktiengesellschaft Process for electrochemical roughening of aluminum for printing plate supports
US5288372A (en) * 1992-07-07 1994-02-22 Alumax Inc. Altering a metal body surface
US5304298A (en) * 1991-09-09 1994-04-19 Hoechst Aktiengesellschaft Process for roughening aluminum or aluminum alloys
EP0689096A1 (en) 1994-06-16 1995-12-27 Eastman Kodak Company Lithographic printing plates utilizing an oleophilic imaging layer

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2009242B (en) * 1977-11-28 1982-05-06 Inoue Japax Res Electroerosion machining
AT375880B (en) * 1980-03-11 1984-09-25 Teich Ag Folienwalzwerk METHOD FOR PRODUCING BASE MATERIAL FOR OFFSET PRINTING PLATES

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2721835A (en) * 1951-07-07 1955-10-25 Shwayder Bros Inc Surface treatment of aluminum articles
US3477929A (en) * 1966-04-18 1969-11-11 Fujitsu Ltd Method of etching aluminum foil in the manufacturing of aluminum electrolytic condensers
US3755116A (en) * 1971-04-17 1973-08-28 Sumitomo Light Metal Ind Process for the production of aluminum base offset printing plates

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2721835A (en) * 1951-07-07 1955-10-25 Shwayder Bros Inc Surface treatment of aluminum articles
US3477929A (en) * 1966-04-18 1969-11-11 Fujitsu Ltd Method of etching aluminum foil in the manufacturing of aluminum electrolytic condensers
US3755116A (en) * 1971-04-17 1973-08-28 Sumitomo Light Metal Ind Process for the production of aluminum base offset printing plates

Cited By (33)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4140599A (en) * 1975-06-04 1979-02-20 Fujitsu Limited Process for producing porous aluminum anode element
US4087341A (en) * 1975-11-06 1978-05-02 Nippon Light Metal Research Laboratory Ltd. Process for electrograining aluminum substrates for lithographic printing
US4072589A (en) * 1977-04-13 1978-02-07 Polychrome Corporation Process for electrolytic graining of aluminum sheet
US4477317A (en) * 1977-05-24 1984-10-16 Polychrome Corporation Aluminum substrates useful for lithographic printing plates
US4198278A (en) * 1977-06-10 1980-04-15 Toyo Aluminum Kabushiki Kaisha Method for producing anode aluminum foils for electrolytic condensers
US4301229A (en) * 1978-03-27 1981-11-17 Fuji Photo Film Co., Ltd. Electrolytically grained aluminum support for making a lithographic plate and presensitized lithographic printing plate
US4294672A (en) * 1979-05-30 1981-10-13 Fuji Photo Film Co., Ltd. Method for preparing a support for a lithographic printing plate
US4976198A (en) * 1979-08-16 1990-12-11 Fuji Photo Film Co., Ltd. Grain structure for lithographic printing plate supports
USRE31743E (en) * 1980-09-15 1984-11-20 Sprague Electric Company AC Etching of aluminum capacitor foil
US4279714A (en) * 1980-09-15 1981-07-21 Sprague Electric Company AC Etching of aluminum capacitor
US4279715A (en) * 1980-09-15 1981-07-21 Sprague Electric Company Etching of aluminum capacitor foil
US4332651A (en) * 1981-05-20 1982-06-01 Sprague Electric Company AC Etching of aluminum capacitor foil
US4336113A (en) * 1981-06-26 1982-06-22 American Hoechst Corporation Electrolytic graining of aluminum with hydrogen peroxide and nitric or hydrochloric acid
US4581996A (en) * 1982-03-15 1986-04-15 American Hoechst Corporation Aluminum support useful for lithography
GB2127435A (en) * 1982-09-24 1984-04-11 Sprague Electric Co Etching aluminium capacitor foil
US4427506A (en) 1982-09-24 1984-01-24 Sprague Electric Company AC Etching of aluminum capacitor foil
US4655136A (en) * 1983-02-14 1987-04-07 Hoechst Aktiengesellschaft Sheet material of mechanically and electrochemically roughened aluminum, as a support for offset-printing plates
US4576686A (en) * 1983-09-27 1986-03-18 Fuji Photo Film Co., Ltd. Process for producing aluminum support for lithographic printing plates
US4547275A (en) * 1984-02-03 1985-10-15 Showa Aluminum Kabushiki Kaisha Process for treating surface of aluminum foil for use as electrode of electrolytic capacitors
US4600482A (en) * 1984-04-25 1986-07-15 Hoechst Aktiengesellschaft Process for the electrochemical roughening of aluminum for use as printing plate supports, in an aqueous mixed electrolyte
US4618405A (en) * 1984-04-25 1986-10-21 Hoechst Aktiengesellschaft Process for the electrochemical roughening of aluminum for use as printing plate supports, in an aqueous mixed electrolyte
US4626328A (en) * 1984-04-25 1986-12-02 Hoechst Aktiengesellschaft Process for the electrochemical roughening of aluminum for use as printing plate supports, in an aqueous mixed electrolyte
US4666576A (en) * 1985-02-06 1987-05-19 Hoechst Aktiengesellschaft Process for the electrochemical roughening of aluminum for use in printing plate supports
US4661219A (en) * 1985-02-06 1987-04-28 Hoechst Aktiengesellschaft Process for the electrochemical roughening of aluminum for use in printing plate supports
US4671859A (en) * 1985-09-20 1987-06-09 Hoeschst Aktiengesellschaft Process for the electrochemical graining of aluminum for use as printing plate supports
EP0268790A2 (en) 1986-10-17 1988-06-01 Hoechst Aktiengesellschaft Process for electrochemically modifying support materials of aluminum or aluminum alloys, which have been grained in a multi-stage process and use of these materials in the manufacture of offset-printing plates
US4824535A (en) * 1986-10-17 1989-04-25 Hoechst Aktiengesellschaft Process for the electrochemical graining of aluminum for use in printing plate supports
US4840713A (en) * 1987-05-26 1989-06-20 Hoechst Aktiengesellschaft Process for the electrochemical roughening of aluminum for use in printing plate supports
US5152877A (en) * 1989-10-13 1992-10-06 Fuji Photo Film Co., Ltd. Method for producing support for printing plate
US5156723A (en) * 1990-01-19 1992-10-20 Hoechst Aktiengesellschaft Process for electrochemical roughening of aluminum for printing plate supports
US5304298A (en) * 1991-09-09 1994-04-19 Hoechst Aktiengesellschaft Process for roughening aluminum or aluminum alloys
US5288372A (en) * 1992-07-07 1994-02-22 Alumax Inc. Altering a metal body surface
EP0689096A1 (en) 1994-06-16 1995-12-27 Eastman Kodak Company Lithographic printing plates utilizing an oleophilic imaging layer

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DE2327764A1 (en) 1974-12-19
DE2327764B2 (en) 1975-08-07
CH566401A5 (en) 1975-09-15
SE381683B (en) 1975-12-15
NL7307879A (en) 1974-12-10
BE801114A (en) 1973-12-19
CA1009606A (en) 1977-05-03
GB1392191A (en) 1975-04-30
FR2237438A5 (en) 1975-02-07

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