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
  • B41N3/03—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
  • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
  • C25D11/00—Electrolytic coating by surface reaction, i.e. forming conversion layers
• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
  • C25D11/00—Electrolytic coating by surface reaction, i.e. forming conversion layers
  • C25D11/02—Anodisation
  • C25D11/04—Anodisation of aluminium or alloys based thereon
  • C25D11/06—Anodisation of aluminium or alloys based thereon characterised by the electrolytes used
  • C25D11/10—Anodisation of aluminium or alloys based thereon characterised by the electrolytes used containing organic acids
• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
  • C25D9/00—Electrolytic coating other than with metals
  • C25D9/02—Electrolytic coating other than with metals with organic materials

Definitions

• the present invention relates to a process for the anodic treatment of aluminum in an electrolyte containing an organic phosphonic, sulfonic or carboxylic acid and the use of the process product as a printing plate support material.
• Surfaces created in such a method are also suitable for capacitors, dielectric purposes, and other applications where a barrier layer is useful.
• Anodized layers produced with phosphoric acid have many good properties that make them suitable for use in offset printing.
• the film produced by anodic oxidation is rather “soft" and has a relatively low abrasion resistance; this is a disadvantage when high D are required jerk pads.
• Anodized layers produced with sulfuric acid are much harder, have a relatively higher abrasion resistance and therefore result in mechanically more resistant offset printing plates with which long print runs can be achieved. Both methods have found their way into practice, each hoodri plates are commercially successful in various areas.
• the sulfuric acid process is also easier to use for the production of thicker anodized layers than the phosphoric acid process, which shows a tendency towards self-limitation due to the greater solubility of the film produced by anodic oxidation in the electrolyte.
• the sulfuric acid process also has certain disadvantages, so there are layers which are not always entirely satisfactory for offset printing substrates, since they tend to not delineate oleophilic and hydrophilic areas sharply enough, so that often with these layers, except for the thinnest, processes must be applied by the z. B. the color acceptance in the non-image areas is prevented.
• This necessary treatment of the anodically produced layer can occasionally be problematic when, for example, it is necessary to produce presensitized offset printing plates in which the adhesion of the radiation-sensitive coating to the support is of primary importance during and after the development of the exposed layer. If such treatments which modify the surface of the carrier material are carried out on the layer produced by anodic oxidation, it is important to find a compromise between achieving sufficient hydrophilicity in the non-image areas and at the same time satisfactory behavior of the image areas. These treatments can thus lead to results that are desirable for offset printing, and are anodized for both phoric acid with P HOS and for the sulfuric acid Aluminum planographic printing plates are known and common in practice.
• the older, non-prepublished EP-A 0 048 909 and 0 050 216 describe processes for the anodic oxidation of plate, sheet or strip material made of aluminum or its alloys, which are contained in an aqueous electrolyte containing at least one polybasic organic acid be performed. If necessary, mechanical, chemical and / or electrochemical roughening can take place before the oxidation.
• the polybasic organic acids include monomeric or polymeric phosphonic, sulfonic or organic carboxylic acids such as phytic acid, tridecyl-benzenesulfonic acid, nitrilotriacetic acid, polyvinylphosphonic acid, polybenzenesulfonic acid or polyacrylic acid.
• the electrolyte can also contain an inorganic acid such as phosphoric acid.
• the process products are preferably used as carrier material in the production of printing plates bearing a radiation-sensitive layer.
• Object of the present invention is to find a method which makes it possible to work in a non-aqueous electrolyte and to obtain layers which are on the one hand thin and rather little-porous, but on the other hand, show E-laminations good adhesion properties to the applied B.
• the invention is based on the process for the anodic treatment of plate, sheet or strip material made of aluminum or its alloys in an electrolyte containing at least one monomeric polybasic organic phosphonic, sulfonic or carboxylic acid, optionally after preceding mechanical, chemical and / or electrochemical roughening.
• the process according to the invention is then characterized in that the non-aqueous electrolyte contains at least one organic solvent with a dipole moment of at least 1.5 as the solvent.
• the method thus relates to the electrolytic deposition of a layer on aluminum, the aluminum to be treated being switched as the anode and any inert metal (such as lead or steel) or graphite as the cathode.
• a possibly pulsating DC voltage is then applied to the previously degreased and optionally roughened carrier through a non-aqueous electrolyte.
• the electrolyte contains at least one of the acids, which is dissolved in the organic solvent or the solvent mixture, which allows a current to flow due to its dipole moment, but which does not undergo any electrochemical reactions at the anode or at the cathode.
• non-aqueous electrolyte precludes the formation of oxides of aluminum and only allows the formation of a non-oxide layer in the manner of an "organometallic" complex.
• a layer produced in this way is highly non-porous and very thin. This results in a very good surface on the aluminum base material, through which better adhesion of coatings to the aluminum support material is achieved than with conventionally anodized surfaces.
• the plates usable in the practice of this invention can be made of aluminum or aluminum alloys such as those with more than 98.5% Al and Be Components such as Mn, Fe, Si, Cu, Zn and / or Ti exist.
• the aluminum strip or the aluminum plate or foil is first freed of its rolling fat, for which purpose it is treated with a suitable degreasing agent, e.g. B. by immersing it in a warm immersion bath with 1,1,1-trichloroethane, trichloroethene, methylene chloride or perchlorethylene or in an aqueous alkaline solution. Then, if necessary, chemical, electrochemical and / or mechanical roughening, for. B.
• the surface is then rinsed with water and rinsed with the organic solvent to be used in the electrolysis bath. This is to prevent water from entering the electrolysis bath.
• the carrier material is then treated electrolytically according to the invention.
• Monomeric polybasic acids suitable for the process according to the invention are, for example: nitrilotriacetic acid, 1,2,4,5-benzene-tetracarboxylic acid, phytic acid, phosphoric acid mono (dodecyloxy-polyoxyethylene) ester, tridecyl-benzenesulfonic acid, dinonyl-naphthalene-disulfonic acid, 2.2 'dinitro-4,4'-stilbene-disulfonic acid, 2-ethyl hexane phosphonic acid, dodecyl-naphthalene-disulfonic acid, di-n-butyl-naphthalene-disulfonic acid, diethylenetriamine pentaacetic acid, ethylenediamine-tetraacetic acid, ethylenediamine-H ydroxy- ethyl triacetic acid and mixtures of ge called acids.
• the most preferred "acids" are phytic acid and
• Such organic solvents are suitable for the invention which have a dipole moment of at least 1.5, preferably of at least 1.7, including (dipole moment in brackets): formamide (3.22), dimethyl sulfoxide (3.96), aniline (1.53) dimethylformamide (3.82), mono- (2.27), di- (2.81), triethanolamine (3.57) and tetrahydrofuran (1.70).
• formamide 3.22
• dimethyl sulfoxide 3.96
• aniline 1.53 dimethylformamide
• mono- (2.27 di- (2.81)
• triethanolamine 3.57
• tetrahydrofuran (1.70).
• the values of DMSO and DMF were from CRC Handbook of Chemistry and Physics, CRC P ress - Boca Raton (USA), 62. Edition 1981/82, p E-60 to E-62, and the other values of Physical Chemistry Paperback, Academic Publishing House Becker & Erler - Leipzig, 1945, Volume I, p. 519 ff.
• the acid can in principle be present in the non-aqueous solution in an amount of 0.01% to the saturation point, preferably in an amount of 0.8 to 5 % .
• the electrolysis temperature is generally kept at -5 to 60 ° C, in particular at 10 to 40 ° C and preferably at 20 to 30 ° C.
• the voltage is entschul- ß strength between 5 and 120 V, preferably between 10 and 60 V, and in particular between 20 and 40 V.
• the electrolysis time should be sufficient to the carrier a charge of 1 to 150 C / dm 2, preferably from 30 to 90 C / dm 2 and in particular from 40 to 70 C / dm 2 .
• the distance between the cathode and anode is usually 1 to 25 cm, preferably between 3 and 15 cm and in particular between about 4 and 10 cm.
• the aluminum surface created according to the invention When the aluminum surface created according to the invention is examined under a scanning electron microscope at a magnification of 30,000 times, an essentially non-porous surface can be seen.
• the surface is fundamentally free from oxide formation and shows excellent adhesion to later applied coatings suitable for offset printing.
• a field of application for a material anodically treated by the method according to the invention is in particular its use as a carrier material in the production of printing plates bearing a radiation-sensitive layer.
• the carrier material is coated with one of the known radiation-sensitive compositions by the consumer.
• An aluminum plate in bright rolled condition is treated for 30 seconds at room temperature in an aqueous NaOH solution.
• the plate cleaned and chemically roughened in this way, is rinsed well with water and, without drying, is then immediately rinsed with dimethyl sulfoxide (DMSO).
• DMSO dimethyl sulfoxide
• the plate is immersed in a solution containing DMSO and 20 g / 1 2-ethylhexanephosphonic acid.
• DMSO dimethyl sulfoxide
• 3,867,147 containing a polycondensation product of 1 mol of 3-methoxy-diphenylamine-4-diazonium sulfate and 1 mol of 4,4'-bis-methoxy is described methyl-diphenyl ether, phosphoric acid, an epoxy resin and a dye in a solvent mixture of ethylene glycol monomethyl ether, tetrahydrofuran and butyl acetate and spin-dried.
• the exposure is then carried out under a test negative in such a way that a fully covered step 6 results on the 21-step Stauffer step wedge.
• the exposed plate is developed and checked for functionality. After inking, the plate shows a very clean background area (non-image areas) that remains clean without any problems.
• the plate Compared to a comparison plate in which the aluminum is hydrophilized by thermal treatment, the plate likewise being roughened alkaline and then treated non-anodically with a 0.5% strength solution of a methyl vinyl ether / maleic anhydride copolymer in dimethyl sulfoxide at about 70 ° C. for 60 seconds the anodized plate achieves a 25% higher print run.
• An aluminum plate is mechanically wet-roughened using a known method using abrasives / nylon brushes and then treated in an aqueous NaOH solution for 30 seconds.
• the roughened plate is rinsed well with water and immediately rinsed thoroughly with formamide.
• the plate coated with the organic solvent is immersed in a solution containing formamide and 25 g / l 2,2'-dinitro-4,4'-stilbene - disulfonic acid.
• a lead electrode which acts as a cathode at a distance of about 5 cm from the aluminum plate.
• the aluminum serves as an anode, to which a voltage of 20 V from rectified alternating current is applied for a period of 60 seconds at room temperature.
• the anodized plate is rinsed well and patted dry.
• the anodically produced layer When the anodically produced layer is removed, its layer weight is determined to be 109 mg / m 2 .
• a plate produced in the same way shows a very hydrophilic surface both in the wet and in the dry coloring test.
• the reaction time in the SnCl- 2 test is 93 seconds
• the reaction time in the zincate test is 137 seconds.
• An aluminum plate is roughened as indicated in Example 2.
• the rinsing is done with formamide.
• the plate covered with the solvent is immersed in a solution containing formamide and 15 g / l 1,2,4,5-benzene-tetracarboxylic acid.
• a lead electrode serving as a cathode at a distance of about 5 cm from the aluminum plate.
• the aluminum acts as an anode, to which a voltage of 20 V from rectified alternating current is applied for a period of 60 seconds at room temperature.
• the treated plate is rinsed well and patted dry.
• the layer weight is 89 mg / m 2 .
• a plate produced in the same way shows a very hydrophilic surface both in the wet and in the dry coloring test.
• the reaction time in the SnCl 2 test is 81 seconds, the reaction time in the zincate test is 133 seconds.
• the light-sensitive coating with the layer specified in Example 1 compared to a thermally treated comparison plate, in which the processing parameters specified in Example 1 are carried out on a mechanically roughened plate can also be used, with the anodized plate a 32% higher print run.
• a wet and dry coloring test reveals a hydrophilic surface.
• the layer weight is measured at 87 mg / m 2 .
• the reaction time for the SnCl 2 test is 104 seconds, for the zincate test 157 seconds.
• the coated plate has good adhesion for the light-sensitive layer and provides an improvement of 20% in the print run compared to the corresponding comparison plate.

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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)
• Electrochemical Coating By Surface Reaction (AREA)

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• 1981
  • 1981-12-23 US US06/333,586 patent/US4388156A/en not_active Expired - Fee Related
• 1982
  • 1982-12-13 DE DE8282111545T patent/DE3278428D1/de not_active Expired
  • 1982-12-13 EP EP82111545A patent/EP0082454B1/fr not_active Expired
  • 1982-12-16 JP JP57219348A patent/JPS58110692A/ja active Pending

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