Chemistry: electrical and wave energy – Apparatus – Electrolytic
Patent
1985-02-13
1986-08-12
Tufariello, T. M.
Chemistry: electrical and wave energy
Apparatus
Electrolytic
C25D 1700
Patent
active
046054804
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
The present invention is concerned with a process and a device for continuously anodically oxidizing one surface of a strip-shaped aluminum or aluminum alloy, which can particularly be used as a support material for offset-printing plates.
Strip-shaped aluminum which has been roughened and anodically oxidized is, for example, required for manufacturing electrolytic capacitors, in the building industry, for packaging materials, or in the production of support materials for offset-printing plates. For these purposes, the strip material is generally cut into smaller sizes.
Support materials for offset-printing plates are provided, on one or both sides, with a radiation-sensitive (photosensitive) coating (reproduction coating), which is applied either directly by the user or by the manufacturer of precoated printing plates and with the aid of which a printing image of an original is produced by a photomechanical route. Following the production of this printing form from the printing plate, the coating support comprises image areas which are ink-receptive in the subsequent printing process while, simultaneously with the image-production, a hydrophilic image-background for the lithographic printing operation is formed in the areas which are free from an image (non-image areas) in the subesequent printing process.
A coating support for reproduction coatings used in the manufacture of offset-printing plates must meet the following requirements:
Those portions of the radiation-sensitive coating, which are comparatively more soluble following exposure must be capable of being easily removed from the support by a developing operation, in order to produce the hydrophilic non-image areas without leaving a residue and without any stronger attack on the support material by the developer.
The support, which has been laid bare in the nonimage areas, must possess a high affinity for water, i.e., it must be strongly hydrophilic, in order to accept water, rapidly and permanently, during the lithographic printing operation, and to exert an adequate repelling effect with respect to the greasy printing ink.
The radiation-sensitive coating must exhibit an adequate degree of adhesion prior to exposure, and those portions of the coating which print must exhibit adequate adhesion following exposure.
The support material should possess good mechanical stability, for example with respect to abrasion, and good chemical resistance, especially with respect to alkaline media.
As the base material for coating supports of this kind, aluminum is particularly frequently used, the surface of this aluminum being roughened, according to known methods, by dry-brushing, slurry-brushing, sandblasting, or by chemical and/or electrochemical treatments. In order to increase the resistance to abrasion, especially electrochemically roughened substrates are additionally subjected to an anodizing step, in order to build up a thin oxide layer. These anodic oxidation processes are conventionally carried out in aqueous electrolytes which contain H.sub.2 SO.sub.4, H.sub.3 PO.sub.4, H.sub.2 C.sub.2 O.sub.4, H.sub.3 BO.sub.3, amidosulfonic acid, sulfosuccinic acid, sulfosalicylic acid or mixtures thereof. The oxide layers built up in these aqueous electrolytes or electrolyte mixtures differ from one another in structure, layer thickness and resistance to chemicals. As already mentioned above, roughened and anodically oxidized materials of this type are of some importance also in other technical fields. In the commercial production of supports for offset-printing plates, aqueous solutions of H.sub.2 SO.sub.4 and/or H.sub.3 PO.sub.4 are, in particular, used.
The prior art has disclosed the following devices and/or processes for continuously anodically oxidizing aluminum strips in a technically appropriate procedure. These devices and/or processes can fundamentally be divided into two groups:
1. The aluminum strip is made the anode by means of a contact roll (contact roller or contact bar) which is positioned outside the anodizing elec
REFERENCES:
patent: 3181461 (1965-05-01), Fromson
patent: 3296114 (1967-01-01), Lloyd
patent: 3359189 (1967-12-01), Cooke et al.
patent: 3420760 (1969-01-01), Freedman
patent: 3471375 (1969-10-01), Cooke et al.
patent: 3632486 (1972-01-01), Herrmann et al.
patent: 3692640 (1972-09-01), Hamabe et al.
patent: 3718547 (1973-02-01), Cooke et al.
patent: 3766043 (1973-10-01), Herrmann et al.
patent: 3865700 (1975-02-01), Fromson
patent: 3871982 (1975-03-01), Idstein
patent: 3902976 (1975-09-01), Walls
patent: 3959090 (1976-05-01), Hoellrigl et al.
patent: 4211619 (1980-07-01), Usbeck
patent: 4214961 (1980-07-01), Anthony
patent: 4226680 (1980-10-01), Cooke et al.
patent: 4248674 (1981-02-01), Leyh
Niederstatter Walter
Sprintschnik Gerhard
Stroszynski Joachim
Hoechst Aktiengesellschaft
Tufariello T. M.
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