Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05D7/00—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials
  • B05D7/14—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials to metal, e.g. car bodies
  • B05D7/16—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials to metal, e.g. car bodies using synthetic lacquers or varnishes
• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C22/00—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
  • C23C22/82—After-treatment
  • C23C22/83—Chemical after-treatment

Definitions

• the invention relates to a method for corrosion protection of metals, in particular iron and steel, by applying a phosphate layer and impregnating the phosphate layer with organic synthetic resin.
• a non-contiguous sealing layer of a hydrophobizing agent for. B. using organic materials, such as based on polyisocyanate modified resin condensation products (DE-AS 11 47820) or to seal with drying oils or low-viscosity paints (H. Fortmann «post-treatment process phosphated iron parts •, metalware industry and electroplating MSV No. 6 (1943), page 229).
• organic materials such as based on polyisocyanate modified resin condensation products (DE-AS 11 47820) or to seal with drying oils or low-viscosity paints (H. Fortmann «post-treatment process phosphated iron parts •, metalware industry and electroplating MSV No. 6 (1943), page 229).
• these agents could not prevail over the chromium-containing aftertreatment solutions for reasons of low quality.
• many of these funds did not lead to useful results.
• the pH of the solution used is usually in the alkaline range, which in the treatment of metal surfaces provided with conversion coatings can be associated with the disadvantage of partial delamination.
• the object of the invention is to provide a method which does not have the disadvantages of the known methods and which provides surfaces with excellent corrosion protection and high abrasion resistance.
• the object is achieved by designing the method of the type mentioned at the outset in accordance with the invention in such a way that a phosphate layer with a basis weight of at least 8 g / m 2 is first produced on the metal surface and at least electrolessly by means of an aqueous solution or dispersion of a cationic synthetic resin 8 g / m 2 synthetic resin applied and baked.
• An advantageous development of the method according to the invention provides for a maximum of 40 g / m 2 of synthetic resin to be applied. Higher application weights practically no longer provide additional corrosion protection.
• phosphate is the only anion in the acidic, aqueous phosphating solution.
• other anions e.g. B. nitrate, nitrite, chloride, sulfate, chlorate, fluoride, complex fluoride, citrate, present.
• the phosphating baths are particularly suitable for the process according to the invention, in which at least a considerable proportion of the iron pickled during the layer formation remains in solution as divalent iron.
• the concentration of the phosphating baths is preferably chosen between 20 and 120 points.
• the application temperature is usually in the range of 40 to 98 ° C.
• the immersion process is preferred for layer formation because it allows the layer weight limit required in the invention to be maintained in a simpler manner than the spray process.
• the phosphating times are usually 4 to 30 minutes.
• the cationic synthetic resins used in the impregnation process according to the invention can be partially or fully neutralized with organic acids or phosphoric acid in the aqueous medium as an emulsion, dispersion and / or colloidal solution.
• the solids content is preferably 5 to 25% by weight.
• the cationic resins are selected from the group of polycondensation and polymerization resins and maintain their cationic function z.
• B. by basic nitrogen-containing groups which form cations after addition of acid in an aqueous medium.
• Cationic acrylate resins can be obtained, for example, by copolymerizing N, N-dimethylaminoethyl methacrylate.
• Cationic resins can also be prepared by reacting Mannich bases of bisphenol A with epoxy resins. Modified epoxy resins which have been made acid-soluble by addition of an amine and in which crosslinking is made possible by addition of a half-capped diisocyanate during baking are particularly suitable for the process according to the invention.
• the cationic synthetic resin from an aqueous solution or dispersion which additionally contains additives and modifiers known from the paint and color formulation, such as colorants, fillers and anti-corrosion pigments, soluble corrosion inhibitors, organic solvents and / or additives for an improved Film flow and to support the networking process when burning
• paint formulations which are used for the cathodic electrocoating of metals.
• they are successfully used as an aqueous medium containing cationic synthetic resin without the use of electric current.
• the organic impregnation film is applied by wetting the phosphated surface with the aqueous solution or dispersion containing the cationic synthetic resin.
• the wetting can be carried out by spraying on, pouring over, immersing and, if appropriate, subsequently spinning off excess liquid.
• a further advantageous embodiment of the invention provides for the cationic resin to be applied by wetting it at least twice with brief drying and subsequent baking.
• the intermediate drying should be carried out until the film has achieved sufficient mechanical strength.
• the baking which concludes the application of the cationic synthetic resin, is usually carried out at object temperatures between 160 and 200 ° C. and holding times of 5 to 30 minutes.
• An advantageous development of the invention consists in post-treating the phosphate layer with known Cr (VI) -containing aqueous passivating agents before the application of the cationic synthetic resin in order to further improve the corrosion protection. They can be formulated based on chromic acid, chromium chromate, alkali dichromate and the like.
• the method according to the invention is particularly suitable for high-quality corrosion protection of Mass parts from the functional area.
• Typical workpieces are screws, nuts, washers, springs, fasteners, brake parts and the like.
• the protective value of the layers produced by the process according to the invention is usually significantly higher than that of chromated, electrolytically produced zinc and cadmium layers.
• degreasing mentioned under 1. or the rust removal and descaling according to 3. can be omitted if the parts to be treated are free of grease or rust or scale.

Landscapes

• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Metallurgy (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Materials Engineering (AREA)
• Mechanical Engineering (AREA)
• General Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Life Sciences & Earth Sciences (AREA)
• Wood Science & Technology (AREA)
• Application Of Or Painting With Fluid Materials (AREA)
• Chemical Treatment Of Metals (AREA)
• Paints Or Removers (AREA)
• Preventing Corrosion Or Incrustation Of Metals (AREA)

Applications Claiming Priority (2)

Publications (2)

Family

ID=6197351

Family Applications (1)

Country Status (9)

Families Citing this family (4)

Family Cites Families (3)

• 1983
  • 1983-04-26 DE DE19833315019 patent/DE3315019A1/de not_active Withdrawn
• 1984
  • 1984-03-20 EP EP84200397A patent/EP0126498B1/de not_active Expired
  • 1984-03-20 DE DE8484200397T patent/DE3464261D1/de not_active Expired
  • 1984-03-29 ES ES84531122A patent/ES531122A0/es active Granted
  • 1984-04-11 PT PT78408A patent/PT78408B/pt not_active IP Right Cessation
  • 1984-04-19 AU AU27137/84A patent/AU2713784A/en not_active Abandoned
  • 1984-04-23 BR BR8401870A patent/BR8401870A/pt unknown
  • 1984-04-24 ZA ZA843025A patent/ZA843025B/xx unknown
  • 1984-04-25 JP JP59083585A patent/JPS59205481A/ja active Pending
  • 1984-04-26 GB GB08410725A patent/GB2138703B/en not_active Expired

Also Published As

Similar Documents

Legal Events